JPH11236820A - Manually operated working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a duct constitution by sucking a combustion air through a combustion air duct by the rotation of a fan impeller fixed on the end of a crank shaft and partitioning this combustion air duct by a duct wall partially covering as the double bottom of a case bottom SOLUTION: A power chain saw 1 has a drive unit 50 provided with an internal combustion engine 2 arranged 10 a casing 17 and a saw chain 41 circulating on a guide rail. A fan impeller 5 is fixed on the end of the crank shaft 4 of this internal combustion engine 2 and the internal combustion engine 2 is cooled by sucking an air in the casing 17 by its rotation. A combustion air is sucked through a flow out port 11 formed on the case bottom 7 formed partially as a double bottom. This flow out port 11 is communicated to the air entrance of an air filter box 19 through a combustion air duct 9 formed on the corresponding part of the end side of a fan case 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine disposed inside a casing, a crankshaft of the internal combustion engine driving a tool and a fan impeller, the fan impeller being disposed in a fan case, and an air inlet. Cooling air is sucked and conveyed to the internal combustion engine, and at that time, combustion air passes through an outlet provided so as to be covered by a fan impeller in a case bottom formed in a radial direction with respect to a crankshaft. The present invention relates to a hand-operated work machine such as a power chain saw that can be discharged axially from a space defined by an end face of a fan impeller and can be supplied to an air filter through a combustion air duct.

[0002]

2. Description of the Related Art In a power chainsaw disclosed in U.S. Pat. No. 3,994,067, an air-cooled internal combustion engine is arranged in a casing of the power chainsaw. The crankshaft of the internal combustion engine carries a driven member for a tool at one end, that is, a driven member for a saw chain orbiting on a guide rail. The other end of the crankshaft drives a fan impeller. The fan impeller is disposed in the fan case, sucks cooling air through an air inlet, and conveys the cooling air to the internal combustion engine. The partial flow, which is a part of the intake air of the fan impeller, is discharged as combustion air to the air filter of the internal combustion engine. The combustion air is axially discharged through an outlet provided at a case bottom formed in a radial direction with respect to the crankshaft so as to be covered by a fan impeller, and supplied to an air filter through a combustion air duct. In the case of this known device, the configuration is such that the air is discharged in the axial direction from the space in which the suction air to be centrifugally separated is defined by the case bottom and the end face of the fan impeller. A relatively clean combustion air is already supplied.

In the case of the above-mentioned known device, an outlet is formed at the center of the bottom of the case, that is, provided near a crankshaft bearing provided in a crankcase of an internal combustion engine.
The combustion air duct connected to the outlet cannot carry the required amount of combustion air unless it has a sufficiently large cross-sectional cross section over its entire length, but in the case of the above-mentioned known device, it is provided at the bottom of the case. The communication of the combustion air duct with the outlet and the air filter and the communication with the carburetor of the internal combustion engine downstream in the direction of flow are achieved with a complex arrangement. Due to the complicated duct guide of the combustion air duct, the structural volume of the working machine is large, which limits the operability and operating comfort of the working machine.

[0004]

SUMMARY OF THE INVENTION The object of the invention is to provide a working machine of the kind mentioned at the outset in which the construction of the hand-operated working machine is made as simple as possible, so that clean combustion air can be easily guided. It is to be.

[0005]

The above object is attained by claim 1.
According to the above, the problem is solved by that the combustion air duct is defined by the case bottom and the duct wall of the fan case partially covering the case bottom as a double bottom.

According to another aspect of the present invention, the combustion air duct extends into a hollow support beam of a work implement for a drive unit having an internal combustion engine. Is solved by

In a combustion air duct defined by a case bottom and a fan case duct wall partially covering the case bottom as a double bottom, air is directed at a shortest distance, ie, the crankshaft extends. It is guided in a direction perpendicular to the existing direction and supplied to the air filter. The combustion air duct can extend over a large radial portion of the case bottom, so that a shallow depth of the double bottom case bottom provides a sufficiently large flow-through cross section, thus saving space and providing large flow through A cross section is obtained. The combustion air duct is completely provided at the end face of the blower case at the height of the outlet provided at the bottom of the case, and the combustion air duct is at least formed by projecting the duct wall tangentially from the circumferential direction of the case bottom in the flow direction. If it is formed partially in the circumferential direction of the fan case, the combustion air duct can be extended to the shortest length and a particularly compact configuration can be obtained. In this case, the duct wall is connected to the peripheral wall of the fan case, which covers the fan impeller in the axial direction, with a distance from the surface of the case bottom, and defines a peripheral duct portion on the outer surface of the peripheral wall. I have. The flow-through cross section provided in the end duct covered by the case bottom is continuously reduced in the flow direction of the combustion air duct, in which case the required flow-through cross section is provided by expanding the peripheral duct section Is done.

Advantageously, the combustion air duct is completely behind the plane of the case bottom at the end portion in front of the inlet to the air filter or the air filter space, so that the axial extension distance is reduced. Therefore, the fan case can be arranged near the crankcase of the internal combustion engine, which is preferable in terms of making the working machine compact.

In order to reduce the structural volume of the drive unit of the hand-operated working machine, the combustion air is supplied to a hollow carrying beam of the working machine. A combustion air duct extends into the carrier beam to which the drive unit and the guide or carrier element, and possibly other components of the implement, are fixed. In this case, the inlet provided on the wall of the carrier beam is covered by the outlet provided on the bottom of the case of the fan case. The air-guiding connection for guiding the combustion air removed from the fan case in the axial direction into the carrier beam is made of a resilient material, is form-fittable to the opening used, and has an additional It is advantageous to couple with a connecting duct member, which can also act as a vibration damping element.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings. The hand-operated working machine shown in FIG. 1 is a power chain saw 1. The power chain saw 1 includes a drive unit 50 and a tool that circulates on a guide rail, that is, a driven saw chain 41. The drive unit 50 has the internal combustion engine 2 arranged in the casing 17 of the power chain saw 1. The internal combustion engine 2 is an air-cooled two-stroke engine in the illustrated embodiment, and is supplied with combustion air and cooling air via a fan described in detail below. The drive unit 50 further has a fuel tank 23 and an air filter 18. The combustion air flows through the air filter 18 in front of the inlet of the internal combustion engine 2 to the cylinder 3. The drive unit 50 is fixed to the carrying beam 13 of the power chainsaw 1. The carrying beam 13 further has a holding element and a grip element of the power chain saw (both not shown).

The drive pinion of the saw chain 41 is driven by a crankshaft 4 of the internal combustion engine on a side (not shown) of the internal combustion engine 2. In this case, the driven shaft of the chain pinion can be connected to the drive end of the crankshaft 4 via a not-shown centrifugal clutch. On the opposite side of the internal combustion engine 2, ie on the side shown, the end of the crankshaft 4 drives the fan impeller 5. The fan impeller 5 is arranged in the fan case 6 and sucks in cooling air by air entering into the casing 17 of the power chain saw. The fan case 6 has a case bottom 7 extending in the radial direction with respect to the axis of the crankshaft 4 between the fan impeller 5 and the internal combustion engine 2, and a peripheral wall 12 that covers the fan impeller 5 in the axial direction. I have. The peripheral wall 12 guides the air conveyed by the fan impeller 5 and is formed from a part of the bottom on the internal combustion engine 2 side. This forms a cooling air outlet. By appropriately extending the peripheral wall 12, the fan case 6 is formed as an induction spiral which opens towards the internal combustion engine 2, in which case the cooling air passes through the cooling air outlet and into the cooling ribs formed in the cylinder 3. Sprayed.

The case bottom 7 has an outlet 11 covered by the fan impeller 5, and combustion air can be sucked through the outlet 11 from a rear chamber defined by the case bottom 7 and the fan impeller 5. The inlet 11 may be divided into windows by 11 ′ by one or more reinforcing strips formed as part of the case bottom 7. Such a strip is advantageously formed so as to extend radially with respect to the crankshaft 4, as indicated by the dashed lines in the figure. In the rear room covered by the fan impeller 5, there is suction air which is filtered in advance by the cyclone action. This suction air is released axially through the outlet 11,
It can be supplied to the air filter 18. Air filter 18
Is a filter cover 2 for closing the contaminated space 21.
It is located in the air filter box 19 which is covered by zero. The clean air side of the air filter 18 communicates with the fuel metering device of the internal combustion engine 2. The fuel metering device is a carburetor in this embodiment.

The combustion air duct 9 connects an outlet 11 provided in the case bottom 7 of the fan case 6 to an air inlet of an air filter box 19 communicating with the contaminated space 21. The air filter box 19 is almost at the height of the cylinder 3 of the internal combustion engine 2 and shortens the flow path to the carburetor. The carburetor is normally arranged adjacent to the fresh air inlet of the cylinder 3. The outlet 11 provided in the case bottom 7 is located on the opposite side of the cylinder 3 of the crankshaft 4,
As a result, disadvantageous heating of the combustion air due to being disposed near the internal combustion engine 2 is prevented. The flow path in the combustion air duct is made as short as possible and the drive unit 5
The case bottom 7 is partially formed as a double bottom in order to guarantee a compact configuration of the power chain saw 1 and improve the operability of the power chain saw 1. As described above, the combustion air duct 9 is formed in a corresponding portion on the end face side of the fan case 6. In this end face duct portion, the case bottom 7 itself and the duct wall 8 of the fan case 6 covering the case bottom are covered.
Is defined by The duct wall 8 is provided to protrude in a tangential direction from the outer periphery of the case bottom 7, and is spaced from one surface of the case bottom 7 by a peripheral wall 12 of the fan case 6.
Is bonded to the outer surface. The duct wall 8 is also shaped as follows: the combustion air duct 9 has, in the flow-through direction, firstly, in addition to the duct wall 8, said end face duct portion defined by the case bottom 7, Peripheral wall 12
At a peripheral duct portion defined by a duct wall. In this case, the cross-section of the end duct in the direction of flow of the combustion air duct 9 is continuously reduced, and the cross-section of the peripheral duct is correspondingly enlarged.

Thus, the axial depth of the fan case 6 having the compactly formed combustion air duct 9 is as small as possible, and the case bottom 7 of the fan case 6 is directly connected to the internal combustion engine 2 and its crankcase. Since the contact can be made, the structural volume of the drive unit 50 can be reduced. The outlet 11 is located at a radial position with respect to the axis 29 of the crankshaft as follows: the end duct portion projecting from the surface of the case bottom 7 in the sector having the outlet is located below the crankcase. At a radial position such that The optimum separation result of the particle load of the suction air is obtained when the position radius of the outer ridge of the suction port 11 is approximately 0.5 to 1.4 times the radius of the fan impeller 5. In this case, it is advantageous that the position radius of the suction port 11 is 0.84 times. A particularly good separating action is when the suction opening 11 extends beyond the fan impeller 5 in the radial direction. Advantageously, the radius of the outer ridge in this case is approximately 5% above the fan impeller. In order to make the cross section of the flow-through as large as possible, it is expedient if the radius of the inner ridge of the inlet 11 is as small as possible.

The combustion air duct extends in the direction of rotation of the fan impeller 5 in the fan case 6. At its end, the combustion air duct is formed completely as a peripheral duct and has an end connection member with a peripheral edge. An elastic bellows 16 which forms a connection to the inlet connection member of the air filter box 19 is attached to the end connection member. The bellows 16 bridges a vibration gap adjacent to the internal combustion engine 2 and buffers the vibration of the drive unit 50 by its elastic material characteristics. Advantageously, the bellows 16 is implemented as a damping element for an internal combustion engine. The fan case 6 having the combustion duct 9 will be described later with reference to FIGS.

In another embodiment of the fan case, the outlet is formed at the bottom of the case on the side of the air filter in order to shorten the combustion air duct, so that a good separation quality of the contaminant particles without losing the power of the engine. Has been achieved. Advantageously, the ratio of the length to the diameter of the duct is 2 or less. This is possible, for example, by providing the outlet at the bottom of the case so as to be located above the flange surface of the cylinder flange. The combustion air duct is formed in the tank case in a compact configuration.

The fan impeller 5 carries blade rings 30, 31 on both end surfaces in the axial direction. The blade rings 30 and 31 are separated by a radial wall 36 formed from the base body of the fan impeller 5. On the side of the fan impeller 5 opposite to the internal combustion engine 2,
A blower ring 31 for sucking cooling air is provided. The blade portion 30 on the suction side on the side of the rear chamber or the case bottom 7 does not serve as a blower, but is contained in the combustion air sucked from the internal combustion engine 2 through the rear chamber and the combustion air duct 9. Used to centrifuge contaminant particles. The structure and operation of the fan impeller 5 are shown in FIG.
This will be described in more detail with reference to FIG.

FIG. 2 shows another configuration of the power chain saw, which shows a configuration in which the configuration of the power chain saw is simplified and clean combustion air is sucked from the fan case 6 in the axial direction. As already mentioned, the power chainsaw, as usual, has a carrier beam 13 for fixing the components of the drive unit (internal combustion engine, tank, air filter, etc.) and the casing of the power chainsaw. The carrier beam 13 has a front portion extending to engage the underside of the internal combustion engine and an upward rear portion. At the end of the rear part, a carburetor 25 is arranged at the height of the cylinder of the internal combustion engine. Further, a hand grip 24 having an operation lever for a chainsaw is fixed to the carrying beam 13. The handgrip 24 is behind a substantially flat wall 42 formed in the upwardly directed portion of the carrying beam 13. The vaporizer 25 is fixed to the wall 42. According to the invention, the carrier beam 13 is designed to be hollow, in which case the combustion air duct 9 ′
Extends inside this hollow carrier beam 13, so that no separate components need to be arranged for the combustion air duct, so that construction space can be saved. Carrying beam 13
Has an opening 43. The opening 43 is covered with the opening 11 provided on the case bottom 7 of the fan case 6. An elastic bellows 16 ′ is provided to hermetically couple the outlet 11 of the fan case 6 and the opening 43 of the carrier beam 13. The bellows 16 'can be connected by its compressible end portions to the openings 11, 43 respectively assigned to these end portions. By elastically coupling the fan case 6 and the carrier beam 13, the disadvantageous transmission of vibrations that occur during operation of the power chainsaw is avoided.

FIG. 3 is a perspective view of the fan case of the power chain saw shown in FIG. 1 as viewed from the end face side of the casing where no cooling air inlet is provided. When the power chainsaw is completely assembled, the end face not provided with the cooling air inlet is covered with a fan grid of the power chainsaw having an opening as an air inlet. The fan case 6 includes the crankshaft axis 2
It has a case bottom 7 formed perpendicular to the case 9 and a peripheral wall 12 oriented in a direction perpendicular to the case bottom 7. The peripheral wall 12 covers the fan impeller rotating in the fan case 6 in the axial direction. The case bottom 7 has an opening 45 at the center, through which the crankshaft of the internal combustion engine projects into the fan case 6 to drive the fan impeller. The radius of the peripheral wall 12 with respect to the crankshaft axis 29 increases in the direction of rotation of the fan impeller, so that an air guiding spiral is formed between the fan impeller and the peripheral wall 12. The peripheral wall 12 is open at the bottom part facing the internal combustion engine in the assembled state, so that a directional cooling air outlet 22 is formed at the end of the air guiding spiral. As already explained with reference to FIG. 1, the case bottom 7 is provided with an outlet 11. Outlet 11 is cooling air outlet 2
2 are substantially diagonally opposed to the outlet 11
Thereby, the combustion air can be discharged in the axial direction from the rear chamber formed between the case bottom 7 and the fan impeller. The size of the cross-section of the outlet 11 must be selected according to the mass flow of the combustion air to be conveyed,
In this embodiment, it extends at an arc angle of 70 °.

The combustion air duct 9 connected to the outlet 11 has an end face duct portion 9s covered by the case bottom 7 and forming a double bottom case bottom, and a peripheral duct portion 9u continuing in the flow direction. Have. In the area of the inflow duct of the combustion air duct, the duct wall 8s of the peripheral duct portion 9u protrudes from the surface of the case bottom 7, and at the end face duct portion 9s the axial protuberance and the radial extension of the combustion air duct And a flow-through cross-section comprising Thus, in the region of the end face duct portion 9s, a combustion air duct is formed between the double bottom case bottom and is defined by the duct wall 8s and the case bottom 7. The duct wall 8 s protrudes tangentially from the outer periphery of the case bottom 7 in the direction of flow of the combustion air, and is connected to the peripheral wall 12 so as to increase the interval with respect to the surface of the case bottom 7. . The duct wall 8u defines a combustion air duct on the outer surface of the peripheral wall 12 in the region of the peripheral duct portion 9u.

In the case of the illustrated embodiment, the fan case 6 is implemented in two parts, the base having the case bottom 7 and the peripheral wall 12 and forming the wall area of the duct wall 8u belonging to the peripheral duct portion 9u. Case and end face duct component 4
6. The end face duct component 46 is connected to the case bottom 7 of the base body at the end face of the fan case 6 on the internal combustion engine side. The end duct component 46 has a wall area 8s of the duct wall of the combustion air duct, which defines an end duct section 9s. The wall region 8s protrudes from the surface of the case bottom 7. The wall region 8s extends in an arc shape, and surrounds the crankcase of the internal combustion engine when the fan case 6 is mounted, so that the fan case 6 can be arranged close to the internal combustion engine.

As can be seen from FIG. 4, a projecting mounting edge 48 is formed on the back surface of the case bottom 7. The mounting rim 48 facilitates securing the end duct component 46 to the base case. Duct wall 8s of end duct component 46 and duct wall 8u forming peripheral duct 9u
Has the following shape, that is, the cross section of the combustion air duct crosses through despite the fact that the cross section at the end face side is reduced and the cross section formed in the circumferential direction is enlarged. The surface has a generally uniform overall cross section and is thus shaped so that the required amount of combustion air can be sucked in without flow losses. The duct wall 8 u forms an end connection member 15 in the end region of the combustion air duct, and the end connection member 15 protrudes radially from the peripheral wall 12 of the fan case 6. The duct wall portions 8u, 8s of the fan case 6 or the end face duct component 46 which can be assembled therewith form a circling edge 15, whereby an elastic bellows 16 is applied to the end connecting member 14. Can be. The combustion air duct is integrally formed in the fan case and is therefore completely gas tight, preventing contaminant particles from being drawn in from the leak location of the duct.

A cut-out portion 27 is provided in the case bottom 7 below the opened circular arc portion of the peripheral wall 12 to make the supply of cooling air to the cooling ribs of the cylinder more convenient. Further, by such a cut-out portion 27, the warm air enters into the rear chamber of the case bottom, and passes through the outlet formed in the case bottom 7 so as to face the diagonal direction, and the combustion air already heated in advance is formed. Is transported. This is particularly advantageous during winter operation of the power chainsaw. If the temperature change is expected to be severe when the power chainsaw is operated for a relatively long time, the mixing of already pre-heated air is advantageous, but in summer operation, the internal combustion temperature rises due to the rising temperature of the combustion air. In the case where the engine may be overheated, it is easily possible to provide a second outlet 11 for discharging the combustion air in the axial direction at the bottom of the case instead of the cutout portion 27. A second combustion air duct is connected to the second outlet 11. The second combustion air duct is releasable to the first combustion air duct during winter operation of the power chainsaw using a suitable air guiding device.

FIG. 5 is a perspective view showing an advantageous embodiment of the fan impeller. The fan impeller 5 carries blade rings 30, 31 on both end surfaces. The blade rings 30 and 31 are provided so as to be partitioned by a radial wall 36 formed by a base body of the fan impeller 5. The fan impeller 5 is fitted by its boss 28 to the crankshaft of the internal combustion engine as follows and non-rotatably connected, i.e. the end face of the fan impeller, which is also provided as the discharge side 33 (this end face has a blade cross section). The blade portion 30 is provided so as to be directed in the radial direction) and is fitted so as to be close to the bottom of the case of the fan case and is connected so as not to rotate relatively.
Thus, the radial wall 36 defines a rear chamber for carrying out the combustion air in the axial direction as described above. A blade ring 31 is formed on the suction side 32 on the opposite side of the fan impeller 5, and its rotating blades suck cooling air and accelerate it by a cyclone action in the fan case.

By directing the blade cross section 34 of the blade portion 30 in the radial direction, the blower action of the blade portion 30 during rotation is reduced, that is, the blade portion 30 is directed in the centrifugal direction, and is therefore opposite to the flow direction of the suction air. Directionally oriented, reducing blower action that reduces power by affecting the gas exchange process of the internal combustion engine. Blade part 30
Has a low negative pressure in the rear chamber due to its weak blower action, and as a result, has little effect on the power of the internal combustion engine sucked from the rear chamber through the combustion air duct. The blade cross section 34 of the blade section 30 is enlarged in the circumferential direction of the fan impeller as the radius increases. By implementing the blade in such a tapered manner, a radial velocity gradient of the suction airflow below the fan impeller 5 is advantageous. The blade cross-section 34 of the fan-spread blade is the radial axis 35 of the fan impeller 5.
Are asymmetrically formed.

The blade ring 30 is formed narrower in the axial direction than the blade ring 31 provided on the suction side 32 of the fan impeller, so that a large cooling air mass flow is conveyed to the cooling ribs of the internal combustion engine. Be guided. The axial width of the blade section 30 substantially determines the through-flow cross section of the rear chamber for passing through the cooling air partial flow which is drawn in as combustion air. The blade section 30 has as high a blade height as possible in order to obtain a large cross-section in the rear chamber. In order to advantageously select the size of the fan-shaped spreading blade portion, it is preferable to increase the axial distance between the radial wall 36 and the bottom of the fan impeller case, and to increase the width of the rear chamber as much as possible.

The blade height of the blade section 30 is advantageously 5 mm. To achieve optimal separation,
The distance between the blade and the case bottom 7 in the axial direction should be as small as possible. This axial spacing compensates for component tolerances and is, for example, 1-2 mm.

The radial wall 36 is curved toward the inside of the impeller and toward the suction side 32. Correspondingly, the axial extension of the rear chamber increases towards the boss 28 of the fan impeller 5. Due to the volume increase of the rear chamber in its inner region, the pressure pulsation caused by the alternating suction during the working cycle of the internal combustion engine is suppressed. The blade section 30 exerts the desired centrifugal force on the particles contained in the flow-through air by means of the smallest possible blower action on the air flow, so that the particles are separated and therefore before the combustion air enters the air filter. Is subjected to pre-filtering.

The fan impeller 5 forms a magnet wheel of a magnetic ignition device, and carries an ignition magnet 49 on its outer periphery. The ignition magnet 49 is arranged on the discharge side 33 of the blade part 30 and extends in the circumferential direction of the radial wall 36 of the blower ring 31 and in the axial direction. The ignition magnet 49 is inserted on the peripheral surface of the flywheel member 47 of the fan impeller 5. The fan impeller 5 has two flywheel members 47 facing each other diagonally. Both of these two flywheel members 47 may include an ignition magnet.

By arranging the ignition magnet 49 and the flywheel member 47 in the blade portion 30, pulsation is generated to prevent backflow in the direction opposite to the suction direction to the rear chamber. Does not affect action.

As indicated by the broken line, it is advantageous that the blade portion 30 protrudes from the end face of the flywheel member 47 of the fan impeller 5. With this configuration, a centrifugally acting blade is disposed over the entire circumference of the blade ring on the discharge side 33 of the fan impeller 5. The end surface of the flywheel member 47 is separated from the surface of the free end of the blade portion 30 inside the impeller, so that when the fan impeller 5 is mounted,
An orbiting annular gap forms in the rear chamber. In this way,
The generation of noise when air flows through the discharge side 33 of the fan impeller 5 can be suppressed.

In order to suppress the flow resistance at the time of air guiding in the rear chamber and the combustion air duct (this flow resistance must be eliminated by the suction force of the internal combustion engine), a blower is provided on the discharge side 33 of the fan impeller 5. The thrust blower ring may be formed at the same radial position as the outlet provided at the bottom of the fan case in addition to the blade portion which is as ineffective as possible. This thrust blower ring
When the fan impeller rotates, it passes through the outlet and pushes the combustion air from the outlet into the combustion air duct, thus assisting the suction force of the internal combustion engine.

FIG. 6 is a sectional view in a closed embodiment of the fan impeller, that is, an embodiment in which the discharge side of the fan impeller 5 is radially covered by a cover disk 40 that rotates together.
The cover disc 40, together with the radial wall 36 of the fan impeller 5, defines a duct-like rear chamber part 10 'which allows centripetal flow. A partial flow of the cooling air sucked by the blower ring 31 of the fan impeller and centrifuged in the fan case as described above is used as the combustion air 44,
Through 0, it is sucked into the closed rear chamber part 10 '.
From the rear chamber 10 formed between the case bottom 7 of the fan case and the cover disk 40, the internal combustion engine sucks combustion air in the axial direction through the outlet 9 of the case bottom 7 as described above. Notches 38 are formed in the cover disk 40 in the circumferential direction. These notches 38
Allows the combustion air 44 to enter the rear chamber 10 which is separated from the rear chamber portion 10 'by the cover disk 40. Thrust blower blades are arranged between the individual notches 38 of the cover disk 40. The thrust blower blade is used for recovering a pressure loss generated when the thrust flows radially through the rear chamber duct 10 ', particularly the blade portion 30. The space formed between the cover disk 40 of the fan impeller and the case bottom 7 is closed by a non-slidable packing outside the outlet 11 in the radial direction, so that the rear chamber on this path is provided. Air flow into 10 is avoided, and combustion air 44 is forced to pass through closed rear chamber duct 10 '. In this embodiment, the rear room 1
Numeral 0 is sealed by a labyrinth-type thrust packing 39.

In the illustrated embodiment, the cover disk 40
Is formed in a double wall, whereby the closed rear chamber duct is first guided centrifugally from the entrance of the blade part 30 towards the inner notch 38 into the first part 10 ′, Behind the notch is oriented towards the second part 10 ''. Since the outlet 11 of the case bottom 7 is located as far as possible in the radial direction, the combustion air 4
4 is accelerated in a second rear chamber duct section 10 ″ before entering the rear chamber 10 and flowing into the combustion air duct 9.

[Brief description of the drawings]

FIG. 1 is a perspective view of a power chain saw.

FIG. 2 is a perspective view of a combustion air duct formed in a carrier beam of the power chain saw.

FIG. 3 is a perspective view of a fan case.

FIG. 4 is a perspective view of the fan case of FIG. 3 as viewed from the opposite side.

FIG. 5 is a perspective view of a fan impeller.

FIG. 6 is a perspective view of an embodiment in which a fan impeller is closed.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Power chain saw 2 Internal combustion engine 4 Crankshaft 5 Fan impeller 6 Fan case 7 Case bottom 8, 8u, 8s Duct wall 9, 9u, 9s Combustion air duct 10 Back room 11 Outlet 18 Air filter 41 Saw chain

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 35/10 F02M 35/10 301K (72) Inventor Jörg Schlossalzig Germany 71364 Vinenden Posttor 23 (72 Inventor Hans Nickel Federal Republic of Germany Day 71554 Kottenweiler Lerchenstrasse 6 (72) Inventor Harald Schliemann Federal Republic of Germany Day 71334 Wei Bringen Gargenbergstrasse 31 (72) Inventor Gunther Stein Federal Republic of Germany Day 71364 Vinenden Wiesenthalstrasse 27/4 (72) Inventor Peter Stucke United States 23462 Virginia Virginia Beach Weller Boulevard 234

Claims (20)

[Claims] An internal combustion engine (2) is disposed inside a casing (17), and a crankshaft (4) of the internal combustion engine (2) is connected to a tool (4).
1) and the fan impeller (5) are driven, the fan impeller (5) is arranged in the fan case (6), and the cooling air is sucked in from the air inlet and transferred to the internal combustion engine (2).
At this time, the combustion air passes through an outlet (11) provided so as to be covered by a fan impeller (5) in a case bottom (7) formed in the radial direction with respect to the crankshaft (4), and then the case bottom It can be discharged in the axial direction from the space (10) defined by the end face (33) of the fan impeller (5) and the air filter (18) through the combustion air duct (9, 9u, 9s). In the hand-operated work equipment that can be supplied, the combustion air duct (9, 9u, 9s) is connected to the case bottom (7).
And a duct wall (8, 8u, 8s) of a fan case (6) partially covering a case bottom (7) as a double bottom. 2. A fan impeller (8, 8u, 8s) projecting tangentially from the outer periphery of the case bottom (7) and spaced from the surface of the case bottom (7). 5) is connected to the peripheral wall (12) of the fan case (6) covering the axial direction, and the peripheral duct portion (9, 9u, 9s) of the combustion air duct (9, 9u, 9s) defined by the peripheral wall (12). 9 u) is formed. 3. The cross section of the end duct (9s) covered by the case bottom (7) is continuously reduced in the direction of flow of the combustion air duct (9, 9u, 9s). 3. The working machine according to claim 2, wherein the flow-through cross section of the peripheral duct portion (9 u) is correspondingly enlarged. 4. The work implement according to claim 1, wherein the air duct (9, 9u, 9s) is formed entirely at its end as a peripheral duct (9u). 5. An air filter (1) is provided in a fan case (6).
8) for connecting the air filter box (19) for connecting the air filter or inside the air filter box (19).
1) Combustion air duct (9, 9u, 9) for connecting
s) the end connection member (14) is formed, the end connection member (14) has a circling edge, and bridges the vibration gap to the air filter (18) or the air filter box (19). Elastic bellows for coupling with (16)
The working machine according to any one of claims 1 to 4, wherein the working machine is attached to the peripheral edge so as to be adjacent to the internal combustion engine. 6. A cooling air outlet (22) formed from a bottom portion of the peripheral wall (12) on the side of the internal combustion engine (2), and an end connection of a combustion air duct (9, 9u, 9s). The work implement according to claim 1, characterized in that the member (14) is adjacent to the cooling air outlet (22). 7. Working machine according to claim 1, wherein the fan case is formed as an induction spiral which opens into the internal combustion engine. . 8. A discharge port (1) provided in a case bottom (7).
Work implement according to one of the preceding claims, characterized in that 1) is on the opposite side of the crankshaft (4) to the internal combustion engine (2). 9. The method according to claim 1, wherein the support radius of the outer ridge of the discharge port is 0.5 to 1.4 times the radius of the fan impeller. The work machine according to any one of the above. 10. The work according to claim 1, wherein a cross section of the discharge port (11) extends in a circumferential direction of the case bottom (7). Machine. 11. A base body having a fan case (6) divided into multiple parts and having a case bottom (7) and a peripheral wall (12), and combustion air protruding from a surface of the case bottom (7). An end wall component (4) having a wall portion of the duct (9)
6. The method according to claim 1, wherein
The work machine according to any one of 0 to 0. 12. An internal combustion engine (2) is disposed inside a casing (17), and a crankshaft (4) of the internal combustion engine (2) drives a tool (41) and a fan impeller (5), and a fan impeller (5) is provided. 5) is disposed in the fan case (6), and sucks cooling air from the air inlet and transfers it to the internal combustion engine (2), where combustion air is formed in a radial direction with respect to the crankshaft (4) Outlet (11) provided in the case bottom (7) to be covered by the fan impeller (5)
Through the space (10) defined by the case bottom (7) and the end face (33) of the fan impeller (5), and can be discharged axially through the combustion air duct (9, 9u, 9s). In a hand-operated work implement, which can be supplied to an air filter (18), a combustion air duct (9) is provided with a work implement carrier beam (13) for a drive unit (50) having an internal combustion engine (2). )
A working machine, characterized in that it extends into a hollow carrying beam (13). 13. The fan impeller (5) carries blade rings (30, 31) on both axial end surfaces thereof, and the blade rings (30, 31) are radially formed by a base body of the fan impeller (5). It is separated by a wall (36), and is located on the suction side (3) of the fan impeller (5).
2) a cooling air suction blower ring (31) is formed, the discharge side (33) is provided with a substantially radially directed blade cross section (34) and the radial wall (3).
13. The work machine according to claim 1, wherein a blade part (30) is formed which projects into the rear chamber (10) defined by (6). 14. A blade cross section (34) of the blade portion (30) expands in the circumferential direction of the fan impeller (5) with an increase in radius, and a radial axis (35).
The working machine according to claim 13, wherein the working machine is formed asymmetrically with respect to the working machine. 15. The working machine according to claim 13, wherein the blade portion (30) is narrower in the axial direction than the blower ring (31). 16. The blade height of the blade section (30) is as large as possible and is at least a quarter of the axial distance between the radial wall (36) and the case bottom (7). The working machine according to any one of claims 13 to 15. 17. The device according to claim 13, wherein the radial wall is curved inwardly of the impeller toward the suction side of the fan impeller.
6. The working machine as described in any one of 6 above. 18. A blade ring (37) passing through a discharge port (11) provided in a case bottom (7) in addition to a blade part (30) on a discharge side (33) on a discharge side (33). 2. The method according to claim 1, wherein
The working machine according to any one of 3 to 17. 19. The discharge side (3) of the fan impeller (5).
3) are radially covered by a co-rotating cover disc (40) and cover discs (4).
No. 0) has a notch (38) at the radial position of the discharge port (11) in the case bottom (7), and discharges in the radial direction between the cover disk (40) and the case bottom (7). A rear room (10) outside the position of the mouth (11)
The working machine according to any one of claims 13 to 18, wherein a non-sliding packing (39) is arranged. 20. A fan impeller (5) carrying an ignition magnet (49) on a peripheral surface thereof, and an ignition magnet (4).
Work implement according to one of the claims 13 to 19, characterized in that 9) is arranged on the discharge side (33) and extends in the axial direction at least up to the radial wall (36).