EP3461594B1 - Gearbox assembly for a driven machine tool - Google Patents

Description

The present invention relates to a gear arrangement of a driven machine tool with an actuator and a gear arrangement for a driven machine tool with a rotating and/or impact-driven tool. Such a driven machine tool can in particular comprise a drilling or impact drill or a hammer drill with or without a chisel function. As a starting point for the present invention, some known solutions of this type are therefore described below.

In known machine tools of this type, especially in rotary hammers, a shaft (motor shaft) driven by a drive unit of the machine tool projects with its front end into the gear arrangement and drives an intermediate shaft via a drive pinion. For example, the German laid-open specification DE 196 51 828 A1 a hammer drill of this type, the intermediate shaft of which is arranged parallel to the drilling tool axis, but at a distance from it. The hammer drill also comprises an air cushion impact mechanism and a wobble drive device that moves back and forth in the direction of the drilling tool axis, the wobble bearing or wobble plate of which is mounted on the rotating, drivable intermediate shaft.

The term wobble drive device refers to a rotation/translation converter device in which the rotational movement of a drive-side element is converted into a linear translational movement of an output-side element. In this case, a rotational element acts on a wobble element, referred to below as a wobble bearing, in such a way that it is driven to tilt back and forth and can thereby set another element into linear translational movement.

For example, as in the DE 196 51 828 A1 disclosed, a translational movement is transmitted to a striking pin of the air cushion impact mechanism, which in turn causes a striking movement of the tool. In addition, the intermediate shaft serves to transmit the drive torque from the driven shaft to the tool. For this purpose, a drive spindle of the machine tool, on which the tool to be rotated can be mounted, comprises a drill sleeve, which, with an external gear ring, engages with the external toothing of a spur gear of the intermediate shaft sitting on the intermediate shaft.

The overall length of the gear arrangement is therefore significantly influenced by the length and position of the impact mechanism. It must be ensured that the wobble bearing does not collide with the driven shaft and/or the spur gear of the intermediate shaft. The distance that must be provided for this purpose between the driven shaft, the wobble bearing and the spur gear of the intermediate shaft means that the gear arrangement as a whole takes up a relatively large amount of installation space, without this space being able to be fully utilized.

In the EN 10 2008 054 458 A1 A hammer drill is also described which has a drive motor with a motor shaft and a tool spindle operatively connected to the motor shaft. A percussion mechanism, which is also operatively connected to the motor shaft, is connected to the tool spindle via a single-stage gear. The single-stage gear comprises a percussion mechanism drive wheel which drives the tool spindle via a crown wheel. The motor shaft of the drive motor in turn comprises a motor pinion, the teeth of which are in operative engagement with a spur gear of the percussion mechanism drive wheel.

Further state of the art is disclosed by the US 4,158,313 A a machine tool comprising a drive spindle for rotating a tool, a coaxial gear ring that can be coupled to the drive spindle, and an intermediate shaft that transmits a drive torque from a driven shaft to the drive spindle. The intermediate shaft has a gear that is in engagement with the coaxial gear ring of the drive spindle. A gear arrangement is also provided that additionally includes a further countershaft with a gear.

These state-of-the-art gear arrangements also require a comparatively large installation space that cannot be fully utilized.

Furthermore, the publication EP 2 700 477 A1 a gear arrangement is known in which a particularly advantageous use of the available installation space is provided by the fact that the gear arrangement additionally comprises a countershaft with a gear which, depending on the operating mode of the machine tool, can be brought into engagement with the coaxial gear ring of the drive spindle or disengaged therefrom.

Although this solution has proven itself in practice, the solution described in it cannot be applied to machine tools that have, for example, an L-shaped housing in which the motor axis in particular is not parallel to the gearbox axis. Rotary hammers in particular have such a housing shape or such an arrangement of gearbox and motor drive unit.

Furthermore, in connection with the actuator used, it has been shown that known solutions from the state of the art require a comparatively large installation space, in particular since additional bolts or rods must be provided inside the housing of the machine tool for their rotationally fixed mounting.

The publication US 6 192 996 B1 discloses a hammer drill with a plurality of selectable operating modes, comprising: a motor, a housing, an intermediate shaft, which has a longitudinal axis and is supported in the housing such that it rotates when the motor is activated, a rotation-transmitting part which is freely rotatably arranged on the intermediate shaft and is displaceable along the longitudinal axis of the intermediate shaft, the rotation-transmitting part, when rotating, transmitting a rotation of the motor to a tool tip attached to the hammer drill; and an impact-transmitting part which is freely rotatably arranged on the intermediate shaft. When rotating, the impact-transmitting part converts the motor rotation into hammer blows and transmits the hammer blows to the tool tip. The hammer drill further has a coupling element which is integrally rotatable with the intermediate shaft and is displaceable along the longitudinal axis of the intermediate shaft to the impact-transmitting part, the coupling element being able to engage the impact-transmitting part and rotate integrally with it when sliding. The hammer drill further comprises a first switching device for external actuation in order to displace at least the coupling element or the rotation-transmitting element; and a second switching device coupled to the first switching device for displacing the clutch element or the rotation transmitting element which is not displaced by the first switching device. The clutch element is also displaceable along the longitudinal axis of the intermediate shaft toward the rotation transmitting part, the clutch element being capable of engaging and rotating integrally with at least one of the rotation transmitting part and the shock transmitting part when sliding, and the engagement state of the clutch element with the rotation transmitting part and with the shock transmitting part being changeable by operation of the first switching device.

The publication CN106041834A also shows another switching unit of an electric hand-held power tool.

The EP 2 444 205 A2 Finally, describes a drill having a housing and a motor that includes an output member. A transmission is disposed in the housing and includes a first output gear and a second output gear. The transmission can selectively couple the output member to the output spindle via the first output gear or the second output gear to rotate the output spindle at a first speed or a second speed. A gear shift assembly includes a guide plate and a user-engageable member. The guide plate can selectively influence movement of the first and second output gears. The user-engageable member can be movable between a first speed position and a second speed position. Movement between the first and second positions can cause the second output gear to at least partially engage the first output gear.

In order to provide a solution in which the available installation space within the housing of the machine tool can be optimally used, the present invention proposes a gear arrangement with the features of claim 1.

With the help of the actuating element, the user can, for example, choose between different operating modes of the machine tool. The actuating element can, for example, comprise a rotary knob, the rotary movement of which, in a known manner, causes a translational movement of the actuator connected to it, which in turn moves the at least one displaceable gear element in the axial direction. Alternative designs are also conceivable, such as an axially displaceable actuating element. According to the invention, the two receiving areas of the actuator together with the shaft sections received therein form bearing points and enable a rotationally fixed arrangement of the actuator within the gear arrangement. Due to its specific design, the actuator according to the invention uses the shaft sections of two gear shafts of the gear arrangement that are already present as bearing points, which are arranged essentially parallel to one another. The actuator can be axially displaced along the two gear shafts and is at the same time secured against twisting around one of the receiving sections. The provision of a switching rod or a guide bolt, as is known from the prior art, is therefore no longer necessary, which advantageously saves both components and installation space. The specific design with a lateral opening on at least one of the receiving sections also enables easy installation.

Thus, the second receiving section of the actuator can comprise a laterally open circular recess, the inner diameter of which corresponds essentially to the outer diameter of the end section of the intermediate shaft and the lateral opening of which encloses less than 180 angular degrees, in particular less than 160 angular degrees, for example 150 angular degrees. Through the lateral opening, ie, Because no circumferential inner peripheral surface is provided, assembly can be simplified. The end section to be accommodated can be inserted laterally through this opening. In a design in which the lateral opening encloses less than 180 degrees of angle, a flattening can also be provided on the shaft section to be accommodated. If the actuator is now rotated in the assembled state relative to the accommodated shaft section, in particular relative to the flattening, a release movement of the accommodated shaft section from the lateral opening can be prevented.

Additionally or alternatively, a preferred orientation of the lateral opening in the installed state of the actuator can ensure that rotation of the actuator about the axis of rotation of the countershaft and thus about the bearing point formed by the first receiving section of the actuator is prevented. The lateral opening is thus oriented in such a way that the received shaft section is engaged behind by the actuator in the installed state and thus counteracts such an undesirable rotational movement.

In particular, it can be provided that the lateral opening of at least one of the receiving sections defines a joining direction for receiving the associated shaft section in the receiving section, which is transverse to a tangential direction defined by the respective other receiving section.

This arrangement ensures that, when mounted, the actuator cannot be moved out of the mounted position by external loads or forces, and in particular the associated shaft section cannot be moved out of the lateral opening by a twisting movement of the actuator. The tangential direction refers to the direction of a tangent around a virtual circle, the center of which coincides with the central longitudinal axis of the shaft section that is in the respective other receiving section. The tangential direction thus defines the direction in which the actuator could rotate around the other receiving area defining a bearing point if it were not secured by the additional receiving area defining another bearing point. The opening direction transverse to this defines a direction that is not parallel to the tangential direction. In the assembled state, this ensures that the shaft section accommodated in the laterally open receiving area is engaged behind by the actuator against a rotational movement.

Furthermore or alternatively, it can be provided that the actuator is firmly connected in the axial direction to at least one displaceable gear element. In this way, an axial displacement of the actuator also directly achieves an axial displacement of the at least one gear element firmly connected to it in the axial direction.

Furthermore or alternatively, it can be provided that the actuator comprises a shift fork which is essentially U-shaped and has a bearing leg, a clamping leg which is essentially parallel thereto and an actuating leg connecting them, wherein the bearing leg has at least one of the receiving sections, wherein the clamping leg is able to clamp at least one displaceable transmission element between itself and the bearing leg and wherein the actuating leg can be connected to the actuating element of the transmission arrangement by means of a connecting structure.

In this case, several gear elements, for example several gears on a gear shaft, can be assigned to a sliding block and move together with it. The sliding block can, for example, be arranged between the bearing leg and the clamping leg, which is essentially parallel to it, so that an axial displacement of the actuator results in an axial displacement of the sliding block. This also applies in the same way to individual gears, which can be arranged between the bearing leg and the clamping leg, which is essentially parallel to it. By simply moving the actuator and the gear elements arranged between the bearing leg and the clamping leg, which is essentially parallel to it, it is possible, for example, to switch between different operating modes of the gear arrangement. This results in a comparatively simple switching mechanism, which can also save installation space and weight.

Alternatively or additionally, it can be provided that the actuator has a tooth-shaped projection which can be brought into engagement with a gear element of the gear arrangement in a switching position of the actuator.

Depending on the design of the gear arrangement, this additional function can solve another problem known from practice, namely that when pure chiseling operation is desired, for example, a drive spindle of the gear arrangement (which carries the machining tool) should not only not be driven in rotation by the drive unit, but should also be held non-rotatably in order to ensure a defined orientation of the tool, particularly when using a flat chisel. The toothed projection can have at least one or more teeth, the outer contour of which forms a counter-contour to the contour of the tooth circle of the gear element, for example the drive spindle. In this way, a reliable locking of the drive spindle is achieved by engaging the counter-contour of the toothed attachment with the outer contour of the tooth circle, for example the drive spindle. Alternative desired fixings or couplings of gear elements of the gear arrangement by means of the actuator are of course also conceivable.

According to a further development, the gear arrangement can comprise a driven shaft, a drive spindle for rotary driving of an attached tool, wherein the drive spindle has a coaxial gear ring, and an intermediate shaft which can transmit a drive torque from the driven shaft to the drive spindle. Furthermore, a countershaft with a coaxial gear and a wobble drive device connected thereto in a rotationally fixed manner is provided, wherein the wobble drive device can convert a rotational movement of the countershaft into a translational movement and transmit it to the drive spindle for the impact drive of the tool. The intermediate shaft has a first gear which can be brought into engagement with the coaxial gear ring of the drive spindle, and a second gear which can be brought into engagement with the coaxial gear of the countershaft, wherein the first and second gears are arranged so as to be displaceable in the axial direction relative to the drive spindle and the countershaft.

In this specific solution, the provision of an intermediate shaft and a countershaft means that the entire gear arrangement can be made shorter in the direction of the drilling tool axis, since the wobble drive device and the torque transmission to the drive spindle can be spatially separated from one another.

In contrast to the solution of the EP 2 700 477 A1 the torque is transmitted from the driven shaft to the drive shaft via the intermediate shaft, but not via the countershaft, as described in the prior art. This specific arrangement, in which the torque is therefore always transmitted via the intermediate shaft and the countershaft is used exclusively to drive the wobble drive device connected to it in order to enable the impact drive of the tool, can prevent undesirable asymmetry. In addition, the torque is transmitted via a non-parallel arrangement of the driven shaft and output shaft, as can be provided for example in an L-shaped hammer drill, is significantly facilitated.

Of course, it is not essential for the invention and therefore not mandatory that the tool can be detachably attached to the machine tool, i.e. the invention can also be implemented in a machine tool in which the tool is not detachably attached to the machine tool but is firmly attached.

The driven shaft is driven by a drive unit, for example an electric motor or a pneumatic drive unit, and transmits the drive torque in the usual way to the intermediate shaft of the gear arrangement. The drive spindle is used to rotate a tool that can be mounted on the machine tool, whereby the intermediate shaft can be brought into engagement with the coaxial gear ring of the drive spindle via a first gear and can thereby transmit the drive torque from the driven shaft to the drive spindle. Because this engagement can also be released, i.e. the first gear of the intermediate shaft can also be brought out of engagement with the coaxial gear ring of the drive spindle, the machine tool can also be operated in which no torque is transmitted, as is desired, for example, when chiseling with a flat chisel.

The torque can also be transmitted to the countershaft via the second gear of the intermediate shaft, which can be brought into engagement with the coaxial gear of the countershaft, thereby driving the wobble drive device that is connected to it in a rotationally fixed manner. This can convert a rotational movement of the countershaft into a translational movement and transmit this translational movement to the drive spindle for the impact drive of the tool. Both the first and the second gear of the intermediate shaft are axially (relative to the longitudinal axis of the intermediate shaft) arranged so as to be displaceable relative to the drive spindle and the countershaft.

According to a further development of the invention, it can be provided that the intermediate shaft comprises a sliding block which is arranged on the intermediate shaft so as to be displaceable in the axial direction between at least two positions and which has the first gear and the second gear. In this embodiment, the first gear and the second gear of the intermediate shaft are therefore displaced axially together relative to the intermediate shaft and, as a result of this displacement movement, are also displaced relative to the drive spindle and the countershaft. The displacement can be enabled between two maximum positions, i.e. between at least two positions. Of course, one or more intermediate positions can be selected between these maximum positions, as will be described in more detail below.

In conjunction with the actuator according to the invention, switching between different operating modes of the machine tool can be achieved by moving the first gear and/or the second gear. The two gears of the intermediate shaft therefore serve not only to transmit torque, but also to switch between different operating modes of the machine tool.

A first operating mode, in which the coaxial gear ring of the drive spindle is in engagement with the first gear of the intermediate shaft and the second gear of the intermediate shaft is out of engagement with the coaxial gear of the countershaft, describes an operating mode in which the drive spindle is only driven in rotation (pure drilling operation).

In a second operating mode of the machine tool, the first gear and the second gear of the intermediate shaft are each in engagement with the corresponding coaxial gear ring of the drive spindle or the coaxial gear of the countershaft. In this operating mode, the drive spindle is not only driven in rotation but also in impact mode. This corresponds to the impact drilling mode of the machine tool.

In a third operating mode, the first gear of the intermediate shaft can be disengaged from the coaxial gear ring of the drive spindle, while the second gear is engaged with the coaxial gear of the countershaft. In this operating mode, no more torque is transmitted to the drive spindle, but only a translational movement generated by the wobble drive device for the percussive drive of the tool (chisel operation).

With the help of the actuating element of the machine tool, the user can choose between the different operating modes of the machine tool. The actuating element can, for example, comprise a rotary knob, the rotary movement of which, in a known manner, causes a translational movement of the actuator connected to it, which in turn moves the sliding block in the axial direction. However, alternative designs are also conceivable, such as an axially displaceable actuating element.

Because the two gears of the intermediate shaft are assigned to the sliding block and move together with it, switching between the three operating modes described can be achieved by simply moving the sliding block. This results in a comparatively simple switching mechanism that can also save space and weight.

In particular, it can be provided that the actuator is firmly connected to the sliding block in the axial direction.

Furthermore, it can be provided that the actuator is arranged in a rotationally fixed manner within the gear arrangement and in particular has a toothed projection which can be brought into locking engagement with the coaxial gear ring of the drive spindle in a switching position of the actuator.

This additional function solves another problem known from practice, namely that in pure chisel operation, the drive spindle should not only not be driven in rotation by the drive unit, but should also be held non-rotatably in order to ensure a defined orientation of the tool, particularly when using a flat chisel. The toothed projection can have at least one or more teeth, the outer contour of which forms a counter-contour to the contour of the tooth circle of the drive spindle. In this way, the drive spindle is reliably locked by engaging the counter-contour of the toothed attachment with the outer contour of the tooth circle of the drive spindle.

In particular, the actuator can be arranged on the sliding block in such a way that an intermediate position is provided in which the projection of the actuator is not yet in engagement with the coaxial gear ring of the drive spindle and fixes it in a rotationally fixed manner, but in which no more torque is transmitted from the intermediate shaft to the drive spindle because the first gear is already disengaged from the coaxial gear ring of the drive spindle. This intermediate position enables, for example, a flat chisel to be set in its desired orientation. If the actuator is then moved further and the toothed projection engages with the coaxial gear ring of the drive spindle, the flat chisel remains in its desired orientation because the drive spindle is now held in a rotationally fixed manner by the actuator, which is also arranged in a rotationally fixed manner, which enables defined machining with a flat chisel.

As already explained above, the actuator has two receiving sections for the rotationally fixed arrangement within the gear arrangement. In the present further development, the first receiving area can be used to receive an end section of the countershaft and the second receiving area can be used to receive an end section of the intermediate shaft. Here too, the two receiving areas of the actuator form bearing points and enable a rotationally fixed arrangement of the actuator within the gear arrangement. Components that are required anyway are used for this rotationally fixed arrangement, which in turn saves space and weight.

In particular, it can be provided that the first receiving section of the actuator comprises a circular recess, the inner diameter of which corresponds essentially to the outer diameter of the end section of the countershaft. The recess is designed as a through hole in order to enable the actuator to be axially displaceable with respect to the intermediate shaft.

Independently of this specific design of the first receiving section, the second receiving section of the actuator can comprise a laterally open circular recess, the inner diameter of which corresponds essentially to the outer diameter of the end section of the intermediate shaft and the lateral opening of which includes less than 180 angular degrees, in particular less than 160 angular degrees, for example 150 angular degrees. This laterally open circular recess can also be designed as a through-hole in order to provide the axial displaceability of the actuator in a simple manner. The lateral opening, i.e. the fact that no circumferential inner circumferential surface is provided, makes assembly easier. The end section to be accommodated can thus be inserted laterally through this opening. In a design in which the lateral opening includes less than 180 angular degrees, a flattening can also be provided on the end section to be accommodated. If the actuator is now moved in the assembled state relative to the accommodated End section, in particular rotated relative to the flattened portion, a release movement of the received end section from the lateral opening can be prevented.

Additionally or alternatively, a preferred orientation of the lateral opening in the installed state of the actuator can ensure that rotation of the actuator about the axis of rotation of the countershaft and thus about the bearing point formed by the first receiving section of the actuator is prevented. The lateral opening is thus oriented in such a way that the end section of the intermediate shaft is engaged behind by the actuator in the installed state and thus counteracts such an undesirable rotational movement.

Furthermore, it can be provided that the gear arrangement also has an air cushion impact mechanism which is connected to the drive spindle. The air cushion impact mechanism can be partially formed integrally with the drive spindle or formed separately and firmly connected to it when assembled. Such an air cushion impact mechanism can comprise a percussion piston, a striker, an exciter sleeve and a drill sleeve in the usual way, whereby the exciter sleeve can be slidably received within the drill sleeve and can form a space with it that accommodates the air cushion. In a known manner, the percussion piston can be set in a back and forth movement within the space by means of the exciter sleeve, which is transferred via the striker to a tool received in the tool holder of the drive spindle. One or more parts of the impact mechanism can be formed integrally with the drive spindle or firmly connected to it.

As already mentioned at the beginning, the driven shaft can be arranged at an angle, in particular at a right angle, to the drive spindle. This makes it possible to provide a compact hammer drill with an L-shaped housing with optimal use of housing space.

Furthermore, it can be provided that the intermediate shaft has a ring gear connected to it in a rotationally fixed manner, which is in meshing engagement with a pinion of the driven shaft. This enables a right-angled arrangement of the intermediate shaft and the driven shaft.

Preferably, the present invention also relates to a machine tool with a housing, in particular in an L-shaped design, in which the housing can comprise at least a first housing part with a first longitudinal axis and a second housing with a second longitudinal axis, and in which the first and second longitudinal axes are not arranged parallel to one another, and with a gear arrangement with one or more of the features described above.

Further features and advantages of the invention will become apparent from the following description of an embodiment of the invention and from the subclaims.

The invention is described in more detail below with reference to the attached figures. The figures show several features of the invention in combination with one another. Of course, the person skilled in the art can also consider these separately from one another and, if necessary, combine them to form further useful sub-combinations without having to be inventive.

Figur 1

eine erfindungsgemäße Getriebeanordnung in einer Seitenansicht;

Figur 2

eine Vorderansicht auf die Getriebeanordnung gemäß Figur 1;

Figur 3

eine schematische Darstellung der erfindungsgemäßen Getriebeanordnung der Figuren 1 und 2 in einer von mehreren unterschiedlichen Betriebsstellungen;

Figur 4

einen Schaltblock der Getriebeanordnung gemäß Figur 2 mit einem erfindungsgemäßen Stellglied;

Figur 5

die erfindungsgemäße Getriebeanordnung gemäß Figur 1 in einer isometrischen Darstellung; und

Figur 6

eine Draufsicht auf einen Teil der Getriebeanordnung gemäß den Figuren 1 und 5.

They show schematically:

Figure 1

a gear arrangement according to the invention in a side view;

Figure 2

a front view of the gear arrangement according to Figure 1 ;

Figure 3

a schematic representation of the gear arrangement according to the invention of the Figures 1 and 2 in one of several different operating positions;

Figure 4

a switching block of the transmission arrangement according to Figure 2 with an actuator according to the invention;

Figure 5

the inventive gear arrangement according to Figure 1 in an isometric representation; and

Figure 6

a plan view of a part of the gear arrangement according to the Figures 1 and 5 .

The Figure 1 shows a gear arrangement according to the invention, which is generally designated by the reference number 10. The gear arrangement 10 comprises a driven shaft 12, which is driven by a drive unit designed as an electric motor M, a drive spindle 14 and an intermediate shaft 20 and a countershaft 30 designed as a wobble drive shaft. The drive spindle 14 has a tool holder (not shown) at its free end 16 facing away from the driven shaft 12 for receiving a tool, for example a drill or chisel. The drive spindle 14 also comprises a drilling sleeve 18, which surrounds it in sections. The drive spindle 14 extends in a longitudinal direction L, which coincides with a tool axis (drilling tool axis).

The intermediate shaft 20 and the wobble drive shaft 30 extend parallel to the drive spindle 14. The respective axes of rotation are arranged parallel to the longitudinal direction L and are not designated in more detail.

The intermediate shaft 20 serves in the present gear arrangement 10 to transmit a drive torque from the driven shaft 12 to the drive spindle 14. For this purpose, the intermediate shaft 20 has a ring gear 22 with a front toothing 22a, which is in engagement with an external toothing 12a of the driven shaft 12. The drive torque of the electric motor M is transmitted to the intermediate shaft 20 via the external toothing 12a and the toothing 22a of the ring gear 22 (see also Figure 3 ). The intermediate shaft 20 also has a switching block or sliding block 44, which positively engages in a spline shaft toothing 46 on the outer circumference of the intermediate shaft 20 and is thus displaceable along the intermediate shaft 20, but is mounted on it in a rotationally fixed manner. The displacement direction of the sliding block 44 is in the Figures 1 and 3 indicated by the double arrow S. In the schematic representation of the Figure 3 the spline gearing 46 is shown over the entire length of the intermediate shaft 20. In reality, however, this can be, for example, Figure 6 shown, also extend only over a limited section of the intermediate shaft 20.

The sliding block 44 has a first gear ring 24 which is in engagement with a gear ring 28 which is connected in a rotationally fixed manner to the drive spindle 14. In this way, the drive torque is transmitted from the intermediate shaft 20 via the first gear ring 24 of the sliding block 44 to the gear ring 28 of the drive spindle 14.

Because the sliding block 44 is designed to be displaceable along the longitudinal axis of the intermediate shaft 20, which coincides with its axis of rotation and is thus parallel to the longitudinal axis L of the drive spindle 14, the first gear ring 24 can be brought into or out of engagement with the gear ring 28 of the drive spindle 14.

The sliding block 44 further comprises a second gear ring 42, which can be brought into engagement with a gear ring 26 of the wobble drive shaft 30 depending on the position of the sliding block 44. Thus, in a corresponding operating position of the sliding block 44, the torque of the intermediate shaft 20 can be used not only to drive the drive spindle 14 by transmitting it via the first gear ring 24 to the gear ring 28 of the drive spindle 14, but also to drive the wobble drive shaft 30 by transmitting the torque via the second gear ring 42 to the gear ring 26 of the wobble drive shaft 30.

In addition, the sliding block 44 comprises a bearing section 74, which will be referred to in more detail in connection with a shift fork 50 surrounding these components.

On the wobble drive shaft 30, which extends parallel to the intermediate shaft 20 and is arranged at a predetermined distance from it (see also Figure 2 ), a wobble drive device 32 is arranged. This comprises a wobble bearing 34, which is connected in a rotationally fixed manner to the wobble drive shaft 30, as well as a connecting means 36, which is accommodated in the manner of a ball joint in a corresponding receptacle 38a of a reciprocating piston or an excitation sleeve 38. The wobble drive device 32 serves in a known manner to convert a rotational movement of the wobble drive shaft 30 into a translational movement T (cf. Figure 3 ) and, if necessary, transfer it to the excitation sleeve 38 via an air spring.

The gear arrangement 10 finally comprises a percussion mechanism 40, which can be designed, for example, as an air cushion percussion mechanism and can comprise a percussion piston, a striker, as well as the exciter sleeve 38 and a drill sleeve, wherein the exciter sleeve 38 can be slidably accommodated within the drill sleeve and can form a space with it that accommodates the air cushion. In a known manner, the percussion piston is set in a reciprocating movement within this space that accommodates the air cushion by means of the exciter sleeve 38, which is transmitted via the striker (not shown) to a tool accommodated in the tool holder of the drive spindle 14. Consequently, if the wobble drive shaft 30 is driven via the gear ring 28, the wobble drive device 32 converts this rotary movement into a translatory movement T, which, with the aid of the impact mechanism 40, produces a striking movement of the picked-up tool.

The following describes the different operating modes of the transmission arrangement according to the invention with reference in particular to the Figure 3 be discussed. The Figure 3 shows in particular an operating position in which the sliding block 44 is shown in an operating position in which the first gear ring 24 is in engagement with the gear ring 28 of the drive spindle 14, while the second gear ring 42 is in rotationally fixed engagement with the gear ring 26 of the wobble drive shaft 30. This operating position shows a percussive drilling operation (hammer drilling position), in which the tool on the one hand carries out a rotary movement and on the other hand also experiences a percussive movement in addition to the rotary movement (hammer drilling operation).

If the switching block 44 is now removed from the Figure 3 shown position along the longitudinal axis of the intermediate shaft 20 (indicated by the double arrow S in the Figure 3 ) is shifted to the right, the second gear ring 42 can be disengaged from the gear ring 26 of the wobble drive shaft 30. In this position, the wobble drive shaft 30 is no longer driven in rotation; the wobble drive device 32 is therefore stationary, so that no more translational movement is transmitted to the drive spindle 14. This operating position therefore describes an operating mode in which the drive spindle 14 is only driven in rotation by means of the intermediate shaft 20 and the first gear ring 24 of the sliding block 44 (drilling position), so that a tool held in the tool holder is only driven in rotation (drilling operation).

Based on the Figure 3 However, in the operating position shown, the sliding block 44 can also be moved to the left in direction S, so that the first gear ring 24 comes out of engagement with the ring gear 28 of the drive spindle 14. In this third operating position, the second ring gear 42 remains in rotating engagement 26 with the wobble drive shaft 30, whereby the wobble drive device 32 continues to be driven and transmits a translational movement T to the drive spindle 14 (chisel position). In this position, a tool held on the tool holder therefore only experiences a purely striking movement, since no more torque is transmitted to the drive spindle 14 via the ring gear 28 (hammer operation or chisel operation).

In order to enable simple switching and at the same time a particularly simple and cost-effective construction, an actuator 50 designed as a shift fork 50 is also provided, which is slidably mounted on the wobble drive shaft 30 at a first bearing point 52 (first receiving section of the actuator). Because the shift fork 50 is slidably mounted on the intermediate shaft 20 at a second bearing point 56 (second receiving section of the actuator), an undesirable pivoting movement of the shift fork 50 about the first bearing point 52 as a result of an undesirable rotational movement of the ring gear 28 is reliably prevented. As in the Figure 4 As can also be seen, the second bearing point 56 is provided with a lateral opening 58 which encloses an angle of less than 180 degrees. This ensures simple assembly and at the same time secure storage of the shift fork 50.

Like in the Figure 4 as well as in the following Figures 5 and 6 As can be clearly seen, the lateral opening 58 of the second receiving section 56 is oriented in such a way that a joining direction F does not coincide with a tangential direction T. The joining direction defines the direction in which the shaft section (bearing section 72) of the intermediate shaft to be received is inserted laterally into the second receiving area 56. The tangential direction T defines the direction of a straight line that runs through the central longitudinal axis of the intermediate shaft 20 and at the same time is tangential to a virtual circular path K whose center coincides with the central longitudinal axis of the wobble drive shaft 30.

Because the joining direction F does not coincide with the tangential direction T, the intermediate shaft 20 cannot be undesirably rotated out of the receiving section 56 when a rotary movement is introduced into the shift fork 50. Instead, the shift fork 50 engages behind the bearing section 74 of the intermediate shaft 20 and, together with the laterally closed recess section 52 (as an additional bearing point), enables the shift fork 50 to be mounted in a rotationally fixed manner relative to the two shafts 20 and 30 without the need for additional components, as is necessary in the prior art.

Like in the Figure 2 As can be clearly seen, an operating element 60 is also provided, which is designed in the form of a rotary handle. If the user now turns the rotary handle 60, which in the assembled state is attached to the outside of the machine tool housing (not shown) and protrudes through it, the rotary movement of the rotary handle 60 is converted in a known manner via an adjusting wire 62 into a translatory movement (operating movement B) of the shift fork 50 and the sliding block 44 connected thereto. For this purpose, the switching wire 62 is connected in a known manner via the holding structures 70, 72 to the shift fork 50 and guided along it.

The shift fork 50 is essentially U-shaped in a plan view (see also Figure 6 ). As shown, it can comprise a bearing leg 64, a clamping leg 66 which is essentially parallel thereto and an actuating leg 68 which connects them. On the bearing leg 64, the two are essentially designed as circular or circular segment-shaped through-openings which form the receiving sections 52, 56 for the respective shaft sections of the intermediate shaft 20 and the wobble drive shaft 30.

The components of the actuator 44 are arranged between the bearing leg 64 and the clamping leg 66 of the shift fork, namely the two gear wheels 24 and 42 as well as the bearing section 74, which are mounted axially displaceably together with the shift fork on the spline toothing 46 of the intermediate shaft 20.

In order to avoid undesired rotation of the drive spindle 14 during hammer or chisel operation, the shift fork 50 has a bearing leg 64 (see also Figure 4 ) has a toothed section 54, the toothing of which corresponds to the external toothing of the gear ring 28. If the sliding block 44 is moved to the left for hammer operation or chisel operation, the switching fork 50 can be brought into rotationally fixed engagement with the gear ring 28 of the drive spindle 14.

Claims (11)

1. A transmission arrangement (10) of a driven machine tool having an actuator (50) which can be connected to an actuating element (60) of the transmission arrangement (10) and, in the connected state, is capable of converting a shifting movement of the actuating element (60) into a displacement of one or more transmission elements (24, 42, 44) of the transmission arrangement (10),

   wherein the actuator (50) has two receiving portions (52, 56) for mounting the actuator (50) within the transmission arrangement (10),

   characterised in that the first receiving portion (52) has a substantially circular recess with a circumferential inner peripheral surface, in which a shaft portion of a first transmission shaft (30) of the transmission arrangement is received, and in that the second receiving portion (56) has a substantially circular recess with a lateral opening (58), in which a shaft portion of a second transmission shaft (20) of the transmission arrangement (10) is received, wherein the lateral opening (58) of the second receiving portion (56) enables simplified mounting of the shaft portion of the second transmission shaft (20) due to the absence of a circumferential inner circumferential surface.
2. The transmission arrangement according to claim 1,
   characterised in that the lateral opening (58) of the second receiving portion (56) defines a joining direction (F) for receiving the associated shaft portion in the receiving portion (56) which is transverse to a tangential direction (T) defined by the first receiving portion (52), the tangential direction denoting the direction of a tangent around a virtual circle whose center point coincides with the central longitudinal axis of that shaft portion which is received in the first receiving portion (52).
3. The transmission arrangement according to claim 1 or 2,
   characterised in that the actuator (50) is axially fixedly connected to at least one displaceable transmission element (24, 42, 44).
4. The transmission arrangement according to any of the preceding claims,
   characterised in that the actuator comprises a shift fork (50) which is substantially U-shaped and has a bearing limb (64), a clamping limb (66) substantially parallel thereto and an actuating limb (68) connecting these, wherein the bearing limb (64) has at least one of the receiving portions (52, 56), wherein the clamping leg (66) is capable of clamping at least one displaceable transmission element (24, 42, 44) between itself and the bearing leg (64), and wherein the actuating leg (68) can be connected to the actuating element (60) of the transmission arrangement (10) by means of a connecting structure (70, 72).
5. The transmission arrangement according to any of the preceding claims,
   characterised in that the actuator (50) has a tooth-shaped projection (54) which can be brought into engagement with a transmission element (28) of the transmission arrangement (10) in a shift position of the actuator (50).
6. The transmission arrangement (10) according to any of the preceding claims for a driven machine tool with a rotatingly and/or percussively driven tool which can be detachably attached to the machine tool, further comprising

   - a driven shaft (12);

   - a drive spindle (14) for rotationally driving a detachably mounted tool, the drive spindle (14) having a coaxial ring gear (28), and

   - an intermediate shaft (20) which is capable of transmitting a drive torque from the driven shaft (12) to the drive spindle (14); and

   - a countershaft (30) with a coaxial gearwheel (26) and a wobble drive device (32) connected thereto in a rotationally fixed manner, wherein the wobble drive device (32) is able to convert a rotational movement of the countershaft (30) into a translational movement (T) and to transmit it to the drive spindle (14) for the percussive drive of the tool,

   characterised in that the intermediate shaft (20) has a first gearwheel (24) which can be brought into engagement with the coaxial gear rim (28) of the drive spindle (14), and a second gearwheel (42) which can be brought into engagement with the coaxial gearwheel (26) of the countershaft (30),
   wherein the first and the second gearwheel (24, 42) are arranged to be displaceable in the axial direction relative to the drive spindle (14) and the countershaft (30).
7. The transmission arrangement (10) according to claim 6,
   characterised in that the intermediate shaft (20) comprises a sliding block (44) which is arranged on the intermediate shaft (20) so as to be displaceable in the axial direction between at least two positions and has the first gearwheel (24) and the second gearwheel (42).
8. The transmission arrangement (10) according to any of the preceding claims 6 to 7, characterised in that it further comprises an air cushion impact mechanism (40) which is fixedly connected to the drive spindle (14).
9. The transmission arrangement (10) according to any of the preceding claims 6 to 8, characterised in that the driven shaft (12) is arranged at an angle, in particular at a right angle, to the drive spindle (14).
10. The transmission arrangement (10) according to any of the preceding claims 6 to 9, characterised in that the intermediate shaft (20) has a ring gear which is non-rotatably connected thereto and which is in meshing engagement with a pinion of the driven shaft (12).
11. A machine tool with a housing, in particular of L-shaped construction, in which the housing comprises at least a first housing part with a first longitudinal axis and a second housing part with a second longitudinal axis and the first and second longitudinal axes are not arranged parallel to one another, and with a transmission arrangement (10) according to one of claims 1 to 10.

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