EP1272737A1

EP1272737A1 - Air motor

Info

Publication number: EP1272737A1
Application number: EP01931593A
Authority: EP
Inventors: Konrad Karl Kettner
Original assignee: Cooper Power Tools GmbH and Co OHG
Current assignee: Apex Tool Group GmbH and Co OHG
Priority date: 2000-04-11
Filing date: 2001-04-11
Publication date: 2003-01-08
Anticipated expiration: 2021-04-11
Also published as: DE50101404D1; ATE258646T1; JP2003530509A; WO2001077497B1; JP3730571B2; US20040071579A1; US6857864B2; DE20006683U1; WO2001077497A1; EP1272737B1

Abstract

An air motor, especially for a screwer, comprises an air rotor which is rotatably supported in a motor cylinder and comprises a plurality of longitudinal slits extending in the longitudinal direction of the rotor for radially guiding lamellae, the air rotor and motor cylinder having formed thereinbetween chambers which can be brought into communication with an air inlet and/or an air outlet. To achieve a high efficiency of the motor together with a more uniform accelerating power, a reduced sound level and less wear while the exhaust air throttling measures are reduced at the same time, the motor cylinder comprises an inner chamber of an essentially triangular cross-section, one chamber each being formed between air rotor and a triangle tip.

Description

DESCRIPTION

AIR MOTOR

The invention relates to an air motor, in particular for a screwdriver, with an air rotor rotatably mounted in a motor cylinder, which has a number of longitudinal slots running in its longitudinal direction for the radial guidance of lamellae, chambers being formed between the air rotor and the motor cylinder, which have an air inlet and / or can be connected to an air outlet.

Such an air motor is known from practice and is installed in a screwdriver. The screwdriver has a compressed air connection in order to be able to supply compressed air to the air inlet of the air motor. The compressed air passes through the air inlet into one of the chambers between the engine cylinder and air rotor and acts on one of the fins. This turns the air rotor. Another chamber then comes into contact with the air inlet, while the chamber which has already been pressurized with compressed air releases the compressed air to the environment again via a corresponding air outlet. As a result of the alternating filling and emptying of the chambers with compressed air and the pressurization of the fins projecting radially outward from the air rotor, the air rotor and the output shaft connected to it rotate in total. A corresponding screwing tool for screwing in or loosening a screw or the like is thereby rotated.

The known air motor has two chambers opposite one another relative to the air rotor. Such an air motor has a relatively high idling speed and overall power. In some cases, the power or the speed of such an air motor must be reduced by exhaust throttle measures.

The invention is therefore based on the object of improving an air motor of the type mentioned in such a way that with a simultaneous good efficiency of the motor, a more uniform acceleration capability, a reduced sound level and less wear and tear while reducing the exhaust air throttling measures are possible.

This object is achieved in connection with the features of the preamble of claim 1 in that the engine cylinder has an interior with an essentially triangular shape. cross section, wherein a chamber is formed between the air rotor and a triangular tip. In this way, the air motor according to the invention has three chambers. Such a three-chamber engine results in a lower engine speed and, at the same time, a more uniform acceleration due to the three chambers. With the same size as a two-chamber engine, there is an increase in torque and also due to reduced speed, a reduced noise level. Due to the lower engine speed when screwing in, complex supply air and exhaust air throttling measures are no longer necessary, especially for screwdrivers that do not switch off. At the same time, due to the lower speed, oil-free running of the engine is more possible than with the known single-chamber and two-chamber engines.

In order to enable self-centering of the air rotor in a simple manner, the interior of the motor cylinder advantageously has a cross section of an isosceles triangle, the axis of rotation of the air rotor being arranged in particular at the intersection of the three center perpendiculars of the corresponding triangle sides.

In order to support the air rotor even better centered in this connection, the triangular sides of the motor cylinder can be convexly curved at least in the area of the respective central perpendicular. The curvature essentially coincides with the curvature of the air rotor.

In order to be able to easily guide the fins along an inner surface of the motor cylinder with their free ends when the air rotor rotates, such an inner surface of the motor cylinder can preferably be convexly curved at least in the region of the triangle tips. In this way, the free ends of the lamellae slide without difficulty along the inner surface, in particular also in the area of the triangle tips.

To simplify the manufacture of the motor cylinder and to enable the air rotor to move as uniformly as possible, the inner surface of the motor cylinder can have the same radii of curvature in the region of the triangular tips.

In order to be able to supply and remove compressed air in a simple manner to the three chambers of the air motor according to the invention, at least one air inlet and one air outlet duct can run adjacent to one another in the longitudinal direction of the air rotor on the outside of each triangular side. A simple manufacture for the air inlet and air outlet duct results if, for example, both ducts are formed in a duct body of the engine cylinder.

In order to be able to easily accommodate the air motor according to the invention in a corresponding screwdriver without overdimensioning, the outer diameter of the motor cylinder should lie on such a circular line that the entire motor cylinder can be used in a screwdriver with a receptacle with a correspondingly larger diameter.

In this context, it is also to be regarded as advantageous if the diameter of the circular line is also substantially smaller than a diameter of a front and / or rear rotor cover. These rotor lids close the chambers at the front and rear ends lying in the longitudinal direction of the air rotor and at the same time serve to support a shaft, which is usually formed in one piece with the air rotor.

An advantageous production of the air motor can result from the fact that the channel bodies extend between the front and rear rotor covers over the entire length of the motor cylinder.

Air can be supplied to the air inlets, for example, from the radial direction relative to the engine cylinder. The air supply can take place between, for example, a rotor cover and the engine cylinder. In a simple embodiment, the rear rotor lid can have at least air inlets for air supply to the air inlet channels.

In order to supply the air in the longitudinal direction of the engine cylinder or air rotor, such an air inlet can be designed as a bore penetrating the rotor lid.

The cross section of the bore and / or air inlet duct can have different shapes. In the simplest case, such a cross section can be circular.

A favorable way of selecting the direction of rotation of the air rotor can be seen when the front rotor cover can be rotated relative to the engine cylinder for the alternative supply of air inlet and outlet channels with air. Thus, on the one hand, the corresponding bores in the tube cover can be connected to the air inlet ducts, for example for clockwise rotation, or to the air outlet ducts in order, for example, to connect them Rotate the air rotor counterclockwise. The corresponding assignment of the bores in the rotor lid determines which of these channels are used for the air inlet or air outlet.

In order to be able to remove the air from the chambers again via the rotor lid, corresponding air outlets can be formed in the front and / or rear rotor lid, which can be connected to the air inlet or air outlet channel, depending on the assignment of the corresponding air inlets in the rotor lid.

Similar to the corresponding air inlets in the rotor lid, the air outlets can be designed as bores running in the longitudinal direction of the motor cylinder. In a further exemplary embodiment of the invention, the air outlet can be designed as an annular recess-shaped outlet recess which is formed in the rotor lid and is at least open to the engine cylinder. This is at least connected to the corresponding air outlet duct for the rapid delivery of air.

To discharge the air from the corresponding chambers, in particular in the radial direction, the outlet recess can be opened radially outwards via an outlet gap.

In order to be able to discharge air to the outside not only via the outlet channel but also at least partially directly from the corresponding chamber, the outlet recess can, when connected to an outlet channel, extend at one of its ends with its other end to a region between the triangular tip and the channel body.

In this way, the outlet recess in connection with a chamber arranged downstream of the correspondingly assigned outlet channel in the direction of rotation of the air rotor can also be connected to discharge air into the environment.

In this context, the outlet recess is sufficiently large if an inner radius of the outlet recess is substantially equal to an outer radius of the air rotor.

In order to be able to supply or remove a sufficient amount of air in the area of the air inlet and air outlet duct accordingly quickly, the air inlet and air outlet duct on the inside of the engine cylinder can have slots which extend over part of their respective length and are open towards the air rotor are separated by a sealing web with which the air rotor is in a sealing system. The air rotor can have, for example, four corresponding longitudinal slots and fins arranged therein. For more uniform acceleration of the air rotor, however, more fins and corresponding longitudinal slots are desirable, such as five, six, seven, eight or more longitudinal slots with corresponding fins. For a smooth running of the air rotor without corresponding imbalance, it is also advantageous if the longitudinal slots with the corresponding fins are equally spaced in the circumferential direction.

In order to be able to safely subdivide the chambers into a partial chamber to be filled with air and to be evacuated by air, a center point angle assigned to the length of the outlet recess in the circumferential direction can be greater than an angle between two adjacent plates.

In order to apply force to the lamellae in the radial direction in a simple manner, even numbers of longitudinal slots and lamellae are preferably used, it being possible for a compression spring to be arranged in each case between two diametrically opposite lamellae.

In order to apply compressed air to the fins at their radially inner ends in addition to or as an alternative to the compression springs, the rear rotor cover can have compressed air recesses arranged around a central bore and extending concentrically to the central bore. Depending on the positioning of the rear rotor cover to the motor cylinder, compressed air is fed to the longitudinal slots in the air rotor, particularly in the areas through the compressed air recesses, in which the corresponding fins in the area of the chambers are pushed out of the air rotor.

In order to supply the lamellae with compressed air uniformly and in the area of the chambers, the compressed air recesses can be arranged at equal distances from one another in the circumferential direction of the central bore and / or be opened laterally to the central bore. Compressed air can be supplied via the central bore to the compressed air recesses in a simple manner via the lateral opening to the central bore.

In order to be able to supply compressed air to the right or left rotation of the air rotor depending on the orientation of the air inlets in the rear rotor lid, an air distributor device for supplying compressed air to the air inlets of the rear rotor lid on the side opposite the air rotor to be arranged.

In a simple exemplary embodiment, the air distributor device can be disc-shaped and have three air distribution grooves running radially outwards from a central air supply bore on the side facing the rear rotor cover.

Corresponding to the shape of the air rotor, the air distribution grooves can be equally spaced from one another in the circumferential direction and, depending on the relative position to the rear rotor cover, can be assigned to a group of air inlets for pressurizing air.

Instead of venting the chambers radially outward relative to the rear rotor lid via the air outlets, in particular when using the air motor according to the invention in essentially straight tools, with angled screwdrivers or the like, the air outlets pass through the rear rotor lid in order to vent the chambers in the axial direction.

In order to be able to switch easily between left and right rotation of the air motor, the rear rotor cover can be latched in two positions relative to the motor cylinder for left and right rotation of the air rotor. At this point it should be noted that, of course, instead of rotating the rear rotor lid relative to the motor cylinder, it is also possible to rotate the front rotor lid and motor cylinder relative to a non-rotatably arranged rear rotor lid and thus to switch between left and right rotation of the air rotor.

In both of the above-mentioned cases, the adjustment can be made in that a changeover button protrudes radially outward from the rear rotor cover or from the front rotor cover or from the engine cylinder. It is also possible that the detent for fixing the two positions for the left and right rotation of the air rotor takes place by means of the switch button.

In order to accommodate rear and front rotor covers and motor cylinders with an air rotor in a simple manner, the air motor can have a motor housing, the motor housing having an air supply channel connected to the air supply bore and a rotor bore supporting the output shaft of the air rotor. In order to be able to absorb the reaction force of the motor cylinder, a pin can be arranged between the front rotor cover and the motor cylinder. The reaction torque of the front rotor cover can be transmitted to the motor housing, for example, by a shear pin or the like.

In connection with the air rotor, it should also be pointed out that its axial position is determined by the two rotor lids, while the radial position is determined solely by the air rotor, with sufficient space remaining between the motor cylinder and motor housing by the corresponding diameter of the motor cylinder being less than that the rotor lid is.

An advantageous embodiment of the invention is explained in more detail below with reference to the figures attached to the drawing.

Show it:

1 shows a longitudinal section through an air motor according to the invention.

2 shows a plan view of a rear rotor cover from the direction of an engine cylinder;

3 shows a view of an air distributor device from the direction of the rear rotor lid;

Fig. 4 is a view from the inside of a partially shown triangular side

Air rotors in the area of the air inlet and outlet duct;

5 shows a section through FIG. 1 along the line V-V for left rotation;

6 shows a section corresponding to FIG. 5 through an engine cylinder, and

Fig. 7 shows a section through Figure 1 corresponding to Figure 5 for clockwise rotation.

1 shows a longitudinal section through an air motor 1 according to the invention. This has an output shaft 51 which extends concentrically to an axis of rotation 16 and which is formed in one piece with an air rotor 3, see FIG. 5. The air motor 1 has in Area of the output shaft 51 a rear rotor cover 31 and spaced from this in the direction of the axis of rotation 16 a front rotor cover 32. A motor cylinder 2 is arranged between the two rotor lids. A disc-shaped air distribution device 61 is arranged next to the rear rotor cover 31. At one end 9, opposite the air distribution device 61, the rear rotor cover 31 has outlet gaps 37 which are open to the outside in the radial direction. These are arranged between the rear rotor cover 31 and the engine cylinder 2.

Rotor cylinder 2, rear and front rotor covers 31, 32 have an essentially circular cross section.

The motor cylinder 2 has in its longitudinal direction 4 or in the longitudinal direction of the air motor 1 side flanks 52, 53, see also FIG. 5, which extend obliquely radially inwards. The side flanks 52, 53 separate the channel body 26 and triangular tips 13, 14, 15, see also FIG. 6. The triangular tips 13, 14, 15 form the corresponding tips of an interior of the motor cylinder 2 that is essentially triangular in cross section.

The substantially circular cross section of the motor cylinder 2 results from the corresponding triangular sides 19, 20, 21, see FIGS. 5 and 6, on the outer sides 23 of which projecting channel bodies 26, both the triangular tips 13, 14, 15 and the channel bodies 26 on their Outer surfaces are rounded and run along a circular line 28, see Figure 6. This circular line 28 has a diameter slightly smaller than the diameter 29 according to FIG. 1.

In FIG. 1, the front rotor cover 32 is in sealing contact with the front end of the motor cylinder 2.

Opposite the engine cylinder 2, an air distribution device 61 is arranged on the side next to the rear rotor cover 31. This has an air supply bore 65 approximately in the center. A stub shaft protruding from the air rotor 3 partially projects into this. The air supply bore 65 is connected to an air supply duct 66 in the motor housing 64. Radially outward, three air distribution grooves 62 protrude from the air supply bore 65 on the side of the air distribution device 61 facing the rear rotor cover 31, see also FIG. 3, which are connected to corresponding air inlets 10, 11 depending on the relative rotational position of the rear rotor cover 31 and the air distribution device 61 . The rear rotor cover 31 has, on its side facing the air distributor device 61, a recess which is arranged concentrically to the axis of rotation 16 and in which a ball bearing 56 is arranged for rotatably mounting the stub shaft of the air rotor 3. Openings of compressed air recesses 59, which are formed in the side of the rear rotor lid 31 facing away from the air distributor device 61, open into the recess. Another exemplary embodiment for such compressed air recesses 59 is shown in FIG. 2.

Analogous to the rear rotor cover 31, the front rotor cover 32 has, in its side facing away from the air rotor 3, a recess which is arranged concentrically to the axis of rotation 16 and in which a ball bearing 55 is likewise arranged. The output shaft 51 of the air rotor 3 extends through this.

The rear and front rotor covers, motor cylinders with an air rotor and air distributor device 61 are arranged in the motor housing 64, which is formed in two parts in the exemplary embodiment shown. A cup-shaped part 68 has the air supply channel 66 in its base and a cover-like part 69 of the motor housing 64 can be screwed onto its free ends.

The rear rotor cover 31 is connected to a changeover button 63 which is guided radially outwards from the rear rotor cover through the motor housing 64 and can be actuated from the outside thereof. The changeover button 63 can be locked in two positions, one position of the rear rotor cover 31 corresponding to a left turn, see FIG. 5, and the other position corresponding to a right turn, see FIG. 7, of the air rotor 3.

A pin 67 is arranged between them to transmit a reaction torque from the engine cylinder 2 to the front rotor cover 32. A corresponding means for transmitting the reaction torque from the front rotor cover 32 to the motor housing 64 is not shown for the sake of simplicity.

FIG. 2 shows a view of an inside of the rear rotor cover 31 from the direction of the motor cylinder 2 according to FIG. 1.

Various bores 34 are arranged in the rotor lid as air inlets 33. A total of six holes 34 are provided, three of which are each provided that Rotation of the front rotor cover 31 relative to the motor cylinder 2, an air rotor 3, see Figure 5, drive clockwise or counterclockwise by supplying compressed air. Outlet recesses 36 are arranged as air outlets 35 between the bores 34. The outlet recesses 36 are designed in the form of part circles and extend over a length 47 in the circumferential direction 48 which corresponds to a center angle 49. Outlet recesses 36 are connected to the surroundings of the air motor 1 radially outward via outlet gap 37, see also FIG. 1.

An inner radius 41 of the outlet recess 36 essentially corresponds to an outer radius 42, see FIG. 5, of the air rotor 3. The diameter 30 of both the rear and front rotor covers 31, 32 is essentially equal to the diameter 29 of the motor cylinder 2.

FIG. 3 shows a front view of the air distribution device 61 from the direction of the rear rotor cover 31 according to FIG. 1. The air supply bore 65 is arranged concentrically to the axis of rotation 16 or in the disk-shaped air distribution device 61. From this extend in the circumferential direction 60 equally spaced three air distribution grooves 62, which are recessed in the visible surface of the air distribution device 61 according to FIG. 3 and are opened laterally in the direction of the air supply bore 65, see also FIG. 1.

FIG. 4 partially shows a view from the inside of the engine cylinder 2 in the area of a channel body 26. In the channel body, an air inlet channel 24 and an air outlet channel 25 extend over its entire length. These are arranged parallel and spaced apart from one another in the channel body, see also FIGS. 5 and 6. On an inner side 43 of the motor cylinder 2, the two channels 24, 25 are opened in the direction of the air rotor 3 via slots 54, 55, see also FIGS. 5 and 6. The slots 44, 45 extend approximately in the center of the channels 24, 25 via one Part of their length.

FIG. 5 shows a section along the line V-V from FIG. 1. The same parts are provided with the same reference numerals and are only mentioned in part.

5 shows in particular the essentially triangular cross section of the motor cylinder 2, which is an isosceles triangle with triangular sides 19, 20, 21 and corresponding triangular tips 13, 14 and 15, see also FIG. 6. The axis of rotation 16 runs through a Intersection 17 of the perpendicular 18 of the triangular Pages 19, 20, 21. In the area of the perpendicular, see FIG. 6, the channel bodies 26, each with an air inlet channel 24 and an air outlet channel 25, are arranged on outer sides 23 of the triangular sides 19, 20, 21. These are opened in the direction of the air rotor 3 via their slots 44, 45. Between the channels 24, 25 a sealing web 46 is arranged, with which the air rotor 3 is in sealing contact.

A chamber 7, 8, 9 is formed between the air rotor 3 and the corresponding triangular tips 13, 14, 15. In the area of the triangle tips, an inner surface 22 of the motor cylinder 2 is convexly curved and the corresponding curvatures have the same radius of curvature in the area of all triangle tips. In the area of the triangle sides 19, 20, 21, the inner surface 22 is slightly convexly curved, in particular the curvature in the area of the sealing web 46 corresponding essentially to the corresponding curvature of the air rotor 3 on its outer circumference.

In the illustrated relative position of the rear rotor cover 31 to the motor cylinder 2, an air inlet 10, see FIG. 2, is connected to a corresponding air inlet duct 24, while the other air inlets 11, see again FIG. 2, open into the chambers 7, 8, 9. The air outlet channels 25 are in connection with the outlet recesses 36 as a corresponding air outlet 12, see FIG. 2. The outlet recesses 36 are arranged with one end 38 in the area of the mouth of the air outlet channel 25 and extend to their other end 39 in the area of the corresponding chambers 7, 8, 9.

In the illustrated position of air inlets 10 relative to air inlet duct 24, the air rotor 3 is rotated clockwise 40 (left rotation). If the rear rotor cover 31 is rotated by approximately 90 ° relative to the engine cylinder 2 until the air inlets 11 are connected to the air outlet ducts 25, these serve as air inlet ducts, while the previous air inlet ducts 24 are connected to the outlet recesses 36 and serve as air outlet ducts. In such a position of the rear rotor cover 31, the air rotor 3 rotates in the counterclockwise direction (clockwise rotation), that is to say opposite to the direction of rotation 40 shown in FIG. 5, see FIG. 7.

After the foregoing, the chambers 7, 8, 9 are connected via the outlet recesses 36 to the outlet gaps 37 and thus to the surroundings of the air motor 1 for the delivery of compressed air contained in the chambers and supplied via the air inlet channels 24. In FIG. 5 it can be seen in particular that the outer radius 42 of the air rotor 3 is essentially equal to the inner radius 41, see FIG. 2, of the outlet recesses 36. Furthermore, the air rotor 3 has eight longitudinal slots 5, in which a corresponding number of fins 6 are guided in the radial direction. Two adjacent slats 6 are each arranged at an angle 50 to one another that is smaller than the central angle 49 that is assigned to the length 47 of the outlet recess 36, see FIG. 2.

A compression spring is arranged between each two diametrically opposed lamellae, which acts on the lamellae radially outwards, see FIG. 7. The distance between two diametrically opposed lamellae remains relatively constant because of the inner contour of the motor cylinder 2, so that the spring stroke is very small and the fatigue strength of the spring is given.

In FIG. 5, as an alternative to the compression springs 57 according to FIG. 7, the rear rotor cover 31 is formed with the compressed air recesses 59, which are partially visible in the longitudinal slots 5, offset radially inward from the extended slats 6. These are used to supply compressed air to the slots and thus to extend the slats.

The three sealing lines between air rotor 3 and motor cylinder 2, see the corresponding sealing webs 46, separate supply air from exhaust air accordingly. A radial clearance between the air rotor and the engine cylinder is as small as possible. The position of the engine cylinder is taken over by the air rotor itself and an external centering, e.g. in a housing, leads to overdetermination of the engine cylinder installation position due to dimensional tolerances.

6 shows a section analogous to FIG. 5 only through the engine cylinder 2. Reference is made to the description in connection with the preceding figures.

FIG. 6 shows in particular how perpendicular bisectors 18 of the triangular sides 19, 20, 21 intersect at a point 17 which corresponds to the axis of rotation 16. In particular in the area of the corresponding base points of the perpendicular 18, the triangular sides on the inside 22 of the engine cylinder 2 are convexly curved, this curvature corresponding in particular in the area of the corresponding sealing webs 46 to the outside curvature of the air rotor 3. The outer contour or outer surface 27 of the motor cylinder 2 runs in the region of the triangular tips 13, 14, 15 and the corresponding channel body 26 curved along a circular line 28 with a diameter 29, see FIG. 1.

FIG. 7 shows a section analogous to FIG. 5 for a clockwise rotation of the air rotor 3. The same parts are provided with the same reference numerals and reference is made to the description of FIG. 5.

FIG. 7 differs from FIG. 5 essentially only in that springs 57 for pressurizing the lamellae are arranged radially outwards in the longitudinal slots 5 and that the rear rotor cover 31 is rotated in the counterclockwise direction by approximately 90 ° with respect to the position according to FIG.

The mode of operation of the three-chamber air motor 1 according to the invention is briefly explained below with reference to the figures.

In the position according to FIG. 5, compressed air is supplied to the chambers 7, 8, 9 via air inlets 10, see FIG. 2, and correspondingly air inlet channels 24 with slots 44. The air rotor 3 rotates in the direction of rotation 40 as a result of the pressurized air acting on the fins 6 which are adjacent to the air inlet ducts 24, see FIG. 5.

When the air rotor 3 rotates, a lamella following in the direction of rotation finally comes into contact with the slot 44 and, in the event of further rotation, the compressed air supplied via the slot acts on it in the direction of rotation 40. The lamella arranged upstream in the direction of rotation 40 reaches outlet recess 36, so that behind this lamella 6 compressed air contained in the corresponding chamber can escape radially outward from the air motor 1, see FIG. 1, via the outlet recess and the corresponding outlet gap 37.

The compressed air supply or compressed air discharge takes place analogously for the remaining channel bodies 26.

If the air inlets 11, see FIG. 7, are connected to the air outlet ducts 25 by rotating the rear rotor cover 31 by approximately 90 ° relative to the engine cylinder 2, the air outlet duct becomes the air inlet duct and the previous air inlet duct becomes a connection with a corresponding outlet recess standing air outlet duct, the action of the corresponding slats by compressed air in the opposite direction to the previous direction of rotation 40 according to Figure 5. The three-chamber air motor results in a lower engine speed than in the two-chamber air motor, so that corresponding exhaust air throttling measures are no longer necessary, especially for screwdrivers that do not switch off. At the same time, the acceleration capacity is very even due to the three chambers and the corresponding number of lamellae, and there is an increase in torque compared to the two-chamber air motor. Due to the fact that the three-chamber air motor continues to run evenly, oil-free running is more possible and the air rotor is advantageously self-centered with a reduced noise level.

Claims

EXPECTATIONS

1. Air motor (1), in particular for a screwdriver, with an air rotor (3) rotatably mounted in a motor cylinder (2), which has a number of longitudinal slots (5) running in its longitudinal direction (4) for the radial guidance of lamellae (6) Has chambers (7, 8, 9) are formed between the air rotor (3) and motor cylinder (2), which can be connected to an air inlet (10, 11) and / or an air outlet (12), characterized in that the motor cylinder (2) has an interior with a substantially triangular cross section, a chamber (7, 8, 9) being formed between the air rotor (3) and a triangular tip (13, 14, 15).

2. Air motor according to claim 1, characterized in that the interior of the motor cylinder (2) has a cross section of an isosceles triangle, an axis of rotation (16) of the air rotor (3) in particular at the intersection of the three perpendicular bisectors (18) of the triangular sides (19, 20, 21) is arranged.

3. Air motor according to claim 1 or 2, characterized in that the triangular sides (19, 20, 21) of the motor cylinder (2) are convexly curved at least in the region of the respective perpendicular perpendicular (18).

4. Air motor according to at least one of the preceding claims, characterized in that the inner surfaces (22) of the motor cylinder (2) is convexly curved at least in the region of the triangular tips (13, 14, 15).

5. Air motor according to at least one of the preceding claims, characterized in that inner surfaces (22) of the motor cylinder (2) in the region of the triangular tips (13, 14, 15) have the same radii of curvature.

6. Air motor according to at least one of the preceding claims, characterized in that on an outer side (23) of each triangular side (19, 20, 21) at least one air inlet and air outlet duct (24, 25) adjacent to each other in the longitudinal direction (4) of the motor cylinder ( 2) run.

7. Air motor according to at least one of the preceding claims, characterized in that the air inlet and air outlet duct (24, 25) are formed in a duct body (26) of the motor cylinder (2).

8. Air motor according to at least one of the preceding claims, characterized in that the outer surface (27) of the motor cylinder (2) in the region of triangular tips (13, 14, 15) and channel body (26) lie on a circular line (28).

9. Air motor according to at least one of the preceding claims, characterized in that the diameter (29) of the circular line (28) is smaller than a diameter (30) of a front and / or rear rotor lid (31, 32).

10. Air motor according to at least one of the preceding claims, characterized in that the channel body (26) extends between the front and rear rotor covers (31, 32).

11. Air motor according to at least one of the preceding claims, characterized in that that at least air inlets (10, 11; 33) for supplying air to the air inlet ducts (24) are formed in the rear rotor cover (31).

12. Air motor according to at least one of the preceding claims, characterized in that the air inlet (33) as the rear rotor cover (31) penetrating bore (34) is formed.

13. Air motor according to at least one of the preceding claims, characterized in that a cross section of the bore (34) has a smaller size than a cross section of the air inlet channel (24).

14. Air motor according to at least one of the preceding claims, characterized in that the bore (34) and / or air inlet channel (24) have a circular cross section.

15. Air motor according to at least one of the preceding claims, characterized in that the rear rotor cover (31) for alternative supply of air from the air inlet and air outlet channel (24, 25) is rotatable relative to the engine cylinder (2).

16. Air motor according to at least one of the preceding claims, characterized in that in the front and / or rear rotor lid (31, 32) air outlets (35) are formed which can be connected to the air inlet or air outlet duct (24, 25).

17. Air motor according to at least one of the preceding claims, characterized in that the air outlet (35) is designed as an annular recess in the rotor lid (31, 32) which is at least open to the motor cylinder (2) and is formed in the outlet recess (12, 36).

18. Air motor according to at least one of the preceding claims, characterized in that the outlet recess (36) is open radially outwards via an outlet gap (37).

19. Air motor according to at least one of the preceding claims, characterized in that the outlet recess (36) when connected to an air outlet duct (25) at one of its ends (38) with its other end (39) into a region between a triangular tip ( 13, 14, 15) and a channel body (26) extends.

20. Air motor according to at least one of the preceding claims, characterized in that the outlet recess (36) in connection with an associated air outlet duct (25) in the direction of rotation (40) of the air rotor (3) downstream chamber (7, 8, 9).

21. Air motor according to at least one of the preceding claims, characterized in that an inner radius (41) of the outlet recess (36) is substantially equal to an outer radius (42) of the air rotor (3).

22. Air motor according to at least one of the preceding claims, characterized in that the air inlet and air outlet channel (24, 25) on the inside (43) of the motor cylinder (2) extending over part of their respective length, in the direction of the air rotor (3) open Have slots (44, 45) which are separated by a sealing web (46) with which the air rotor (3) is in sealing contact.

23. Air motor according to at least one of the preceding claims, characterized in that the air rotor (3) has at least seven longitudinal slots (5) with a correspondingly equal number of fins (6).

24. Air motor according to at least one of the preceding claims, characterized in that a center angle (49) assigned to the length (47) of the outlet recess (36) in the circumferential direction (48) is greater than the angle (50) between two adjacent fins (6) .

25. Air motor according to at least one of the preceding claims, characterized in that a compression spring (57) is arranged between two diametrically opposite slats (6).

26. Air motor according to at least one of the preceding claims, characterized in that the rear rotor cover (31) around a central bore (58) arranged compressed air recesses (59) which extend concentrically to the central bore.

27. Air motor according to at least one of the preceding claims, characterized in that the compressed air recesses (59) are equally spaced from one another in the circumferential direction (60) of the central bore (58) and / or are opened laterally to the central bore.

28. Air motor according to at least one of the preceding claims, characterized in that an air distributor device (61) for supplying compressed air to the air inlets (10, 11) of the rear rotor lid (31) is arranged on its side opposite the air rotor (3).

29. Air motor according to at least one of the preceding claims, characterized in that the air distribution device (61) is disc-shaped and has three air distribution grooves (62) running radially outwards from a central air supply bore on the side facing the rear rotor cover.

30. Air motor according to at least one of the preceding claims, characterized in that the air distribution grooves (62) are equally spaced from one another in the circumferential direction and, depending on the relative position to the rear rotor cover (31), are assigned to a group of air inlets (10, 11) for pressurized air.

31. Air motor according to at least one of the preceding claims, characterized in that the air outlets (12) penetrate the rear rotor cover (31).

32. Air motor according to at least one of the preceding claims, characterized in that the rear rotor cover (31) is latched in two positions relative to the motor cylinder (2) for left and right rotation of the air rotor (3).

33. Air motor according to at least one of the preceding claims, characterized in that a changeover button (63) projects radially outward from the rear rotor cover (31).

34. Air motor according to at least one of the preceding claims, characterized in that the air motor has a motor housing (64) in which the rotor cover (31, 32) and motor cylinder (2) with an air rotor (3) are arranged, the motor housing having a the air supply bore (65) is connected to the air supply duct (66) and has a rotor bore (67) supporting the output shaft of the air rotor.

35. Air motor according to at least one of the preceding claims, characterized in that a pin (67) is arranged between the front rotor cover (32) and motor cylinder (2) for the transmission of a reaction element.