System composed of a machine tool and an external module

Abstract

The present invention relates to a system (50) comprising a machine tool (100) and an external module (10) for providing a micro-hammering or striking function for the machine tool. In micro-hammering, striking movements are generated which are superimposed on a purely rotational movement of the tool (102) of the machine tool and can thus increase the drilling force of the machine tool. The external module (10) has cams (12, 14), one of which is fixed to a shaft and the other of which is fixed to a housing. The cams can be designed or interact such that a striking movement is generated which can be superimposed on the rotational movement of the tool (102) of the machine tool (100).

Description

[0001] SYSTEM CONSISTING OF MACHINE TOOL AND EXTERNAL MODULE

[0002] The present invention relates to a system comprising a machine tool and an external module for providing a microhammering or impact function for a machine tool. During microhammering, impact movements are generated that superimpose a pure rotary movement of the machine tool's tool and can thus, for example, increase a drilling force of the machine tool. The external module has cam disks, one of which is fixed to the shaft and the other to the housing. The cam disks can be designed or interact in such a way that an impact movement is generated that can be superimposed on the rotary movement of the machine tool's tool. The external module can be attached like an adapter between the machine tool and its tool.

[0003] Background of the invention:

[0004] In the field of machine tools, drilling rigs, especially core drilling rigs, are known for cutting essentially cylindrical cores from the subsurface to be processed. Such drilling rigs often have a so-called core bit as their tool, which is driven by a motor in the drilling rig to rotate. Such a drilling rig may have a mechanical transmission unit to operate the drilling rig in various gears and power ranges.

[0005] To increase the working power of such drilling rigs, drilling rigs have been proposed in the prior art that feature an additional percussion mechanism designed to generate percussive movements and impart them to the pure rotary motion of the drilling rig. The result is usually a superimposed movement of rotary and percussive motion, which can be used to work the subsoil.

[0006] The disadvantage of these well-known drilling rigs with integrated impact mechanisms, however, is that they often have to be purchased in addition to conventional drilling rigs, and that the user often has to carry both a conventional drilling rig and a drilling rig with an impact mechanism in order to always carry out the drilling work with the optimally suited device. A further disadvantage is that different requirements apply to the lubricants used for impact and rotary movements. In a drilling rig with an integrated impact mechanism, the areas of the drilling rig in which the rotary and impact movements are generated merge seamlessly into one another, making it impossible to use different lubricants that are optimally adapted to the different challenges.Even if different lubricants are used initially, they will mix over time, so that the advantages of the different lubricants disappear over time. Furthermore, over time, individual components of the machine tool can wear away, with the abraded particles being able to migrate freely within the machine tool. These wear particles can contaminate the lubricants, and these contaminants can reduce their lubrication properties.

[0007] A further disadvantage of drills with an integrated impact mechanism is that the impact movements, particularly those occurring during operation of the impact mechanism, can be transmitted to the user or the drill stand. This can cause pain and wrist strain for the user. Regarding the drill stand, the stability of the connection between the drill and the drill stand can be lost, causing the drill to accidentally detach from the stand and, for example, fall and hit the ground. This is particularly disadvantageous when a battery-operated drill is involved, as batteries or accumulators are very sensitive components of a machine tool.

[0008] For example, US 3 268 014 A discloses a rotary impact hammer having a spindle mounted in a housing for rotating and limited axial movement relative to the housing.

[0009] US 4,489,792 A describes an adapter device for attachment to an output rotary drive of a drill, the drill comprising a drive for transmitting rotary drive and / or impact forces. FR 1 431 911 A discloses an accessory for portable electric drills.

[0010] US 4,450,919 A ​​describes a device that can be attached to a drill, wherein the device can have both a hammering and a drilling function for penetrating hard materials or a drilling function. The object underlying the present invention is to overcome the above-described deficiencies and disadvantages of the prior art and to provide a technical solution for generating percussive movements that can be superimposed on a rotary movement of a tool of a machine tool. The solution should be simple and comfortable to use and handle for the user. Furthermore, an optimal supply of lubricant to the various components of the technical solution should be ensured and mechanical impairments and the transmission of vibrations to the user or any drill stand used should be reduced.

[0011] The problem is solved by the subject matter of the independent claim. Advantageous embodiments of the subject matter of the independent claim can be found in the dependent claims.

[0012] Description of the invention:

[0013] According to the invention, a system is provided, the system comprising a machine tool and an external module for generating an impact movement. The external module can be attached to a machine tool, wherein a tool of the machine tool is designed to execute a rotary movement. In the system, the machine tool and the external module are connected to one another via a first interface and a second interface, wherein the first interface is configured to connect the shaft device of the external module to a shaft device of the machine tool and the second interface is configured to connect the housing of the external module to a housing of the machine tool.

[0014] Preferably, the first interface can be present in a contact area of ​​the shaft devices of the external module and the machine tool, while the second interface is arranged in a contact area of ​​the housing of the machine tool and the external module. It is particularly preferred within the meaning of the invention that the first interface is designed to connect the second partial shaft or the module input shaft of the shaft device of the external module to the shaft device of the machine tool, while the second interface is designed to connect the housings of the external module and the machine tool to one another. By providing the two interfaces between the machine tool and the external module, a flow of force via sensitive components of the machine tool, such as its bearings, is advantageously prevented.In addition, better support is achieved between the external module and the machine tool.

[0015] Advantageously, by providing two interfaces, the power flow can be directed from the gearbox of the external module to the housing, in particular a gearbox housing, of the machine tool, thus providing particularly good protection for the sensitive components of the machine tool. Furthermore, by providing two interfaces, an additional option for supporting the external module on the machine tool can be provided.

[0016] According to the invention, it is preferred that the second interface is configured to transmit a compressive force acting in the axial direction between the housing of the external module and the housing of the machine tool when the micro-hammering function is activated. This is its main function. This axial force transmission advantageously protects the system's bearings, in particular the rolling bearings, since the axial compressive forces are no longer transmitted via the rolling bearings, meaning they are no longer in the force flow. This is particularly useful because the static axial feed forces are often greatly increased dynamically by the micro-hammering function, which could damage rolling bearings. The first interface—between the shaft device of the machine tool and the shaft device of the external module—preferably has the task of transmitting a (drilling) torque, which is its main function.The torque is preferably transmitted from the gearbox of the machine tool to the input shaft of the external module; the transmitted torque can therefore preferably be referred to as “drilling torque” within the meaning of the invention. A secondary function of the second interface is to position the external module relative to the machine tool. Further secondary functions of the second interface are to transmit transverse forces, bending moments and axial tensile forces between the external module and the drilling rig. If, for example, a user of the machine tool generates a feed force in the direction of the substrate to be machined while working with the machine tool, this force can be transmitted via the interface from the gearbox housing of the machine tool to the module housing. The feed force can then be transmitted further to the drill bit via the cam disks and the module output shaft.

[0017] It is preferred in the sense of the invention that the impact movement, with which the rotary movement of the tool of the machine tool can be superimposed, can be switched on and off by moving the cam discs apart in the axial direction so that there is no longer any contact between the cam discs.

[0018] The cam discs can preferably be moved apart by the first cam disc being moved away from the second cam disc. In the sense of the invention, this preferably means that the second cam disc, which is fixed to the housing, remains stationary and is not moved, while the first cam disc, which is fixed to the shaft, is moved away from the second cam disc in the axial direction. The first cam disc can preferably be moved together with the shaft device of the machine tool. However, in the sense of the invention it can also be preferred for the first cam disc to be moved without the shaft device of the machine tool. The shaft device preferably represents the transmission output shaft of the machine tool. In the sense of the invention it is preferred that the first cam disc is in a first position before being moved away from the second cam disc, in which position the microhammering function is provided.In this first position of the first cam, the first cam and the second cam are preferably in contact with each other, and the contact between the cams or their interaction generates the impact movements that can be superimposed on the pure rotary movement of the machine tool or its tool. This state of the system, in which the first cam is in the first position, is preferably referred to as "microhammering mode" within the meaning of the invention.

[0019] According to the invention, it is preferred that the first cam disk, after moving away from the second cam disk, is in a second position in which the system executes an essentially pure rotary movement of the tool of the machine tool. In this second position of the first cam disk, the first cam disk and the second cam disk are preferably not in contact with one another, but rather separate from one another. Due to the lack of contact between the cam disks, no more impacts are generated to superimpose the pure rotary movement, so that the machine tool can be operated, for example, like a conventional core drilling machine without the microhammering function. This state of the system, in which the first cam disk is in the second position, is preferably referred to as "rotary movement mode" according to the invention.

[0020] It is preferred within the meaning of the invention that the first cam disc is moved away from the machine tool in this embodiment of the invention, i.e. that a distance between the machine tool and the first cam disc is increased. It is preferred within the meaning of the invention that the first cam disc can be fixed in a second position with a fastening element. Preferably, the cam disc can be axially fixed in the second position with the fastening element. The fastening element can preferably be designed to set or maintain a distance between the first cam disc and other components of the system comprising the external module and the machine tool. For example, a distance between the first cam disc and a bearing on the main shaft can be set with the fastening element.

[0021] It is preferred according to the invention that the cam disks are moved apart by moving the second cam disk away from the first cam disk. This preferably means that the first, shaft-fixed cam disk remains stationary and is not moved, while the second, housing-fixed cam disk is moved away from the first cam disk in the axial direction. This solution is particularly advantageous when using an external module. In addition to the interface to the cam disk, the housing of the external module only has the interface to the machine tool, which is provided for the transmission of axial force. Therefore, the housing-fixed cam disk can be moved by axially shortening or lengthening the housing in the area of ​​the interface to the machine tool. This is particularly easy to do because the housing is easily accessible and does not move during drilling.According to the invention, it is preferred that the second cam, before moving away from the first cam, be in a first position in which the microhammering function is provided. In this first position of the first cam, the first cam and the second cam are preferably in contact with each other, so that the impact movements can be generated to superimpose the rotary movement of the tool of the machine tool ("microhammering mode").

[0022] According to the invention, it is preferred that the second cam, after moving away from the first cam, be in a second position in which the system executes a substantially pure rotary movement of the tool of the machine tool. In this second position of the first cam, the first cam and the second cam are preferably not in contact with each other, but rather separated from each other ("rotary movement mode").

[0023] It is preferred within the meaning of the invention that the second cam disk is or can be displaced relative to the housing of the external module by an actuating element. Preferably, the second cam disk can be displaced together with the housing of the external module relative to the machine tool. This preferably means within the meaning of the invention that the second cam disk in this embodiment of the invention can be displaced with respect to the shaft device. It is preferred within the meaning of the invention that when using an external module, i.e. an external impact mechanism, it is possible to displace the second cam disk which is fixed to the housing by displacing the housing of the external module axially and relative to the housing of the machine tool. This displacement of the second cam disks can take place in particular relative to the gear housing of the machine tool.This advantageously also makes it possible to achieve a displacement of the second cam disc with respect to the transmission output shaft and / or with respect to the shaft-fixed, first cam disc.

[0024] The external module preferably comprises a first cam disk and a second cam disk, wherein the first cam disk can be connected to a shaft device of the external module and the second cam disk can be fixedly connected to a housing of the external module. It is preferred within the meaning of the invention that the first cam disk and the second cam disk interact to generate the impact movement, wherein the external module is designed to superimpose the impact movement on the rotary movement of the tool of the machine tool. It is preferred within the meaning of the invention that the first cam disk of the external module is designed as a shaft-fixed cam disk, i.e. is connected to a shaft device of the external module, while the second cam disk of the external module is designed as a housing-fixed cam disk, in that the second cam disk is fixedly connected to the housing of the external module.According to the invention, it is preferred that the first cam disc is fixedly connected to the shaft device in the rotational or tangential direction, while the second cam disc is fixedly connected to the housing of the external module in the rotational or tangential direction. The shaft device and the first cam disc are preferably designed to be movable in the axial direction, wherein the shaft device and the first cam disc can preferably move back and forth together, i.e. together, between stops or within a certain area provided for this purpose. The movable design of the shaft device and the first cam disc preferably enables the axial stroke movements of the first cam disc and the shaft device, which generate the impact movements.

[0025] The invention makes it possible to provide a machine tool that can be equipped with an external module to provide a microhammering function. This method of providing a microhammering function is preferably referred to as a "modular solution" within the meaning of the invention, while alternative approaches in which the impact motion is generated within the machine tool itself are referred to as "integrated" solutions.

[0026] One advantage of the invention is that the proposed system or the external module can convert a purely rotary movement of the machine tool into a superimposed rotary and impact movement. Depending on the application to be performed, the machine tool user can decide whether or not to use the external module to generate an impact movement. In other words, the user can use the external module to enable a conventional machine tool, which is designed to generate only a rotary movement, to generate a superimposed rotary and impact movement. The external module can thus be used as a retrofit option for conventional machine tools without an impact function, whereby this retrofitting can advantageously upgrade the machine tool to generate a combined rotary and impact movement.By not generating the impact motion integrated by fixed components within the machine tool, but instead allowing the user to add the impact motion to the tool's rotary motion using the external module, a particularly flexible work and tool system can be created. In particular, the user can use the external module for different machine tools, so that, for example, an entire fleet of machine tools can be equipped to perform a superimposed rotary and impact motion. Furthermore, the user no longer needs to bring two different drilling rigs (with and without impact function) to a construction site when drilling; it is sufficient to carry one drilling rig and the external module.

[0027] The superimposition of the rotary motion of the machine tool's tool with the impact motion generated by the external module is preferably also referred to in the context of the invention as "imposing or impressing an impact motion onto an existing rotary motion of a machine tool or its tool." The impact motions or impacts are preferably referred to as "microhammering." Thus, the invention can, in particular, provide a microhammering function, whereby the generation of the required impact motions is not carried out by way of an integrated solution within the machine tool—as in the prior art—but rather by the external module. As a result, the user of the machine tool is exposed to less stress from the impacts, since the load path is extended by using the external module, and vibrations and impacts can be absorbed by components of the external module and thus significantly reduced.For example, parts of the external module's housing can be made of plastic or be made of plastic, making these plastic components more elastic than steel components and able to absorb shocks and vibrations. In addition, additional damping elements can be provided between the external module and the machine tool to further reduce shocks and vibrations for the user or the drill stand.

[0028] Furthermore, different lubricants can be used in the machine tool and the external module. In particular, within the context of the invention, it is preferred that lubricants optimized for rotary motions be used within the machine tool, while lubricants optimized for impact motions can be used in the external module. This ensures particularly good lubrication of the system and effective protection of the system components against wear.

[0029] The ability to provide a microhammering function makes it possible, in particular, to dispense with the use of rinsing or cooling water when operating the machine tool. This can significantly reduce the level of contamination on a construction site. It can also be used, for example, to carry out core drilling in locations or areas of the construction site where there is no water supply or in areas where the use of rinsing or cooling water is not permitted. This can be the case, for example, near absorbent building materials such as plaster or cardboard, or in sensitive building types such as hospitals or the like, or near electrical installations such as server rooms or control cabinets. Furthermore, working with the machine tool can be made safer, as the combination of electricity and water on a construction site can pose a safety risk.The invention can enable “dry drilling” on a construction site by eliminating the use of flushing or cooling water, which is a significant advantage of the invention.

[0030] The impact movements, which in the context of the present invention are preferably also referred to as “impacts,” make working with the machine tool significantly more efficient. The machine tool can be designed, for example, as a drilling device or as a core drilling device. The tool of the machine tool can then be, for example, a core bit, with which cylindrical drill cores can be cut out of a substrate to be machined. Such drilling devices can, for example, operate with an essentially static, i.e. constant, drilling force. Such a drilling force can, for example, be in the range of 1,000 Newtons (N). The drilling devices and their components are also designed for these drilling forces, i.e. a user can work with this essentially static drilling force without having to fear that damage or mechanical impairments will occur to the machine tool or its components.

[0031] With the proposed external module, impacts with force peaks of up to 10,000 Newtons can advantageously be generated. If the impact mechanism is integrated into the machine tool, as is the case with virtually all devices known from the prior art, such conventional machine tools and their components are exposed to considerable mechanical stresses that can lead to damage to the machine tools and their components. In contrast to this, in the context of the present invention, the generation of the impact movement takes place in or by an external module that can be arranged between the tool and the machine tool. The specific design of the external module described below can significantly reduce these mechanical stresses and risks for the machine tools and their components.

[0032] Advantageously, the drilling force can be significantly increased using micro-impacts, allowing work to be completed more quickly and efficiently with a machine tool equipped with an external impact generation module. This increase in the preferably substantially axially acting drilling force is also referred to in the context of the invention as "increasing the axial drilling force."

[0033] The proposed external module can generate an impact motion that can be superimposed on a rotary motion of a tool of a machine tool. The impact motion preferably represents a substantially axial impact motion, preferably oriented along a shaft running centrally within the system or along a central device axis. The impact motion is preferably generated by an alternating axial stroke between the two cam disks of the external module, wherein the alternating axial stroke is advantageously capable of transmitting a substantially axial drilling force to the tool of the machine tool.

[0034] In accordance with the invention, it is preferred that an input variable for the external module is essentially a pure rotary movement of the machine tool or its tool. This pure rotary movement can be superimposed by the micro-impacts generated by the external module, so that a mixed rotary and impact movement is generated with which a substrate can be machined. The rotary movement of the machine tool can be transmitted from the shaft device of the machine tool, which preferably functions as a transmission output shaft, to the shaft device of the external module and from there further to the tool holder and / or the tool of the machine tool, wherein preferably a torque is also transmitted from the machine tool to its tool at the same time.The external module for generating impact movements can be placed between the machine tool and its tool, which can be used to superimpose the pure rotary movement of the machine tool.

[0035] A further advantage of the invention is that, by providing an external module, the location where the impact movement is generated is separated from the other components of the machine tool, in particular the sensitive gear components. This spatial separation of impact generation and the machine tool allows the components of the machine tool to be particularly well protected from mechanical stress. Furthermore, the spatial separation makes it possible to use different lubricants in the external module and in the machine tool. If, for example, a gearbox, in particular a manual gearbox, is used in the machine tool, the requirements for the lubricant to be used can differ significantly from the lubricant requirements required by the impact mechanism of the external module.Due to the spatial separation, lubricants that are optimally tailored to the respective application can be used in the machine tool and the external module, without the risk of these lubricants mixing undesirably. This can significantly increase or extend the performance and service life of the machine tool, the external module, and their respective components. This is particularly advantageous because it eliminates the need for complex seals, which are common in integrated solutions for impact mechanisms in machine tools. Furthermore, it has been shown that stress on the other gear components of the machine tool caused by abrasion or abrasion particles can be significantly reduced.

[0036] A further advantage of the invention is that, due to the spatial separation and the provision of the external module, vibrations and impacts from the machine tool are transmitted to the user to a lesser extent. The user frequently holds the machine tool in their hands, whereby the machine tool can have one or two handles for this purpose in a known manner. By being able to "interpose" the external module between the tool and the machine tool, the transmission of vibrations that occur during operation of the machine tool is made significantly more difficult. This significantly relieves the strain on the user's joints, particularly the wrists, or alternatively, the user can work with the machine tool for longer periods without reaching vibration or stress limit values. The invention thus also contributes to the health protection of the user of the machine tool to which an external module for generating impact is attached.

[0037] According to the invention, it is preferred that the cam discs each have at least one structural element, wherein the structural elements generate an alternating axial stroke during a rotational relative movement of the first cam disc and the second cam disc. The structural elements can be designed, for example, as protruding ramps or as inwardly projecting ramps. The cam discs preferably each have a surface on which the structural elements can be arranged. According to the invention, it is particularly preferred that the cam discs are designed to be substantially the same or identical with regard to their surfaces.In the sense of the invention, this preferably means that the surfaces of the cam disks that face each other during operation of the machine tool have the same number of structural elements, wherein the structural elements are designed essentially the same or similarly and are arranged at essentially corresponding locations and positions. The cam disks preferably have essentially the same or identical profiles. For example, 5 to 50 structural elements can be provided on one cam disk. In preferred embodiments of the invention, the cam disks can each have 10 to 30 and particularly preferably 15 to 20 structural elements. For example, 17 structural elements can be arranged on the cam disks, wherein tests have shown that particularly uniform and effective impacts can be generated when using cam disks with 17 structural elements.The structural elements can preferably be arranged uniformly on a circumference of the cam discs.

[0038] If the structural elements are ramp-shaped, the structural elements can comprise an inclined plane which extends, including an angle of inclination, between a lowest point and a highest point of the structural element. A height difference between the lowest point and the highest point of the structural elements can, for example, be in a range of 0.1 to 3 mm. Preferably, the height difference can be in a range of 0.3 to 1 mm or, more preferably, approximately 0.5 mm. Height differences of 0.35 or 0.65 mm have also proven particularly suitable for generating an axial stroke with which an effective impact movement can be generated. The cam disks are mounted in the external module such that they have mutually facing surfaces, with the structural elements arranged on the surfaces of the cam disks.The surfaces of the cam discs are pressed against each other during a rotary relative movement of the first and second cam discs, so that a “rattling” movement with recurring axial stroke is generated.

[0039] The structural elements can preferably be designed as inwardly directed recesses or depressions, for example, in the shape of an inwardly directed ramp. However, within the meaning of the invention, it may also be preferred for the structural elements to be designed as projecting elements that protrude from the base surfaces of the cam discs.

[0040] It is within the meaning of the invention that the structural elements of one cam disc are traversed by the structural elements of the other cam disc during a rotary relative movement of the cam discs. The rotary movement preferably comes about because the first cam disc can rotate together with the shaft device of the external module, while the second cam disc remains stationary. This results in a rotary relative movement of the cam discs to one another. The axial stroke preferably comes about because the first cam disc, which is preferably designed to be movable in the axial direction, follows the course of the structural elements of the second cam disc in the axial direction. As a result, the first cam disc can be moved or raised in the axial direction. In particular, the first cam disc orthe shaft to which it is attached is displaced in the direction of the machine tool by this axial stroke, so that the tool of the machine tool is raised by a short distance. If the structural elements are ramp-shaped and comprise an inclined plane, the first cam disk follows the course of these inclined planes. Preferably, the cam disk can jump from the highest point back to the lowest point of the preferably ramp-shaped structural element, resulting in a small jump of the first cam disk in the axial direction. Preferably, this small jump of the first cam disk is preferably referred to as an “axial stroke” in the sense of the invention. The jump of the first cam disk can be transmitted to the tool of the machine tool via the shaft device.

[0041] The preferably sudden fall of the first cam from the highest to the lowest point of the structural elements generates the impact motion, which can then be transmitted as the impact motion of the machine tool to the surface being machined. The impact motion represents, in particular, an impact pulse that can be superimposed on the rotary motion of the machine tool. The impact pulse is generated, in particular, by the first cam coming into contact with or landing on the surface of the second cam after its jump.

[0042] It is preferred within the meaning of the invention that the above-described axial lifting movement of the first cam disc also causes the shaft within the external module to undergo such an axial movement. This is advantageously achieved in that the shaft, which within the meaning of the invention is preferably also referred to as the “module shaft”, is rigidly connected to the first cam disc. The first cam disc can therefore also be referred to as a “shaft-fixed cam disc”, while the second cam disc is stationary and connected to the housing of the external module, i.e. is particularly “housing-fixed”. It is particularly preferred within the meaning of the invention that the cam discs are pressed against or onto one another by the drilling force and slide rotationally onto one another due to the rotary movement of the module shaft.Preferably, the preferably movable first cam disc moves on the preferably stationary second cam disc, so that a relative movement between the cam discs comprises in particular a movement of the first cam disc on the second cam disc.

[0043] According to the invention, it is preferred that the impact movement that can be generated by the external module has a higher frequency than the rotational movement of the machine tool and / or its tool. The axial stroke preferably has a higher frequency than the rotational movement of the machine tool or its tool. According to the invention, this means that the impact movement generated by the external module has a higher frequency than the existing rotational movement of the machine tool. In other words, the external module is designed to generate a number of impacts per unit of time, wherein this number of impacts is greater than a number of revolutions of the tool of the machine tool per the same unit of time. According to the invention, this preferably means that more impact movements are generated per unit of time than rotational movements of the tool of the machine tool take place.The impact movements can therefore be generated preferentially by a higher frequency axial stroke.

[0044] It is preferred within the meaning of the invention that the external module has an extension of the shaft device. The shaft device of the external module, which is connected to the first, "shaft-fixed" cam disk of the external module, can preferably also be referred to as a "module shaft", "gearbox output shaft" or "shaft" within the meaning of the invention, whereby the aforementioned terms are used synonymously in the context of the present invention. It is preferred within the meaning of the invention that the shaft device of the external module comprises a first partial shaft and a second partial shaft, whereby the first partial shaft and the second partial shaft can be connected to one another via an interface. Preferably, the first partial shaft or the second partial shaft can be designed to be stationary in the axial direction, while the other partial shaft is designed to be movable in the axial direction.In this case, the first cam disc can be arranged, in particular, on the partial shaft designed to be movable in the axial direction, so that the first cam disc is also designed to be movable in the axial direction. In a particularly preferred embodiment of the invention, the first cam disc is connected, in particular, to the first partial shaft of the shaft device, so that the first cam disc can preferably rotate together with the first partial shaft of the shaft device.

[0045] The second partial shaft can preferably represent an extension of the shaft device of the external module in the direction of the machine tool. In an alternative formulation, the second partial shaft of the shaft device can also represent an extension of the shaft device of the machine tool into the external module. It is preferred within the meaning of the invention that the second partial shaft can also be referred to as a “module input shaft”, wherein the second partial shaft can be screwed onto a shaft device or gearbox output shaft of the machine tool. The second partial shaft therefore preferably represents an extension of the shaft device or the gearbox output shaft of the machine tool. The second partial shaft of the shaft device of the external module can thus preferably also be referred to as a gearbox output shaft extension.Its task is, in particular, to establish a connection between the external module and the machine tool, wherein the connection between the external module and the machine tool is mediated in particular by a connection between the second partial shaft of the shaft device of the external module and the shaft device of the machine tool (“gearbox output shaft”).

[0046] According to the invention, it is preferred that the first partial shaft can be inserted into a cavity in the second partial shaft. The first partial shaft can have an insertion end in a rear region, with which it can be inserted into the cavity of the second partial shaft. In other words, the module output shaft can be inserted into a cavity in the module input shaft, wherein the module output shaft and the module input shaft together preferably form the shaft device of the external module. In the connected state, the first and second partial shafts or the module output shaft and the module input shaft can rotate with one another, i.e. they are connected to one another in such a way that a rotational movement of one of the two shaft parts ensures that the other shaft part also rotates. According to the invention, it is preferred that both partial shafts of the shaft device orThe module output shaft and the module input shaft execute a common rotary motion. This common rotary motion and the associated torque transmission are preferably enabled by correspondingly designed contours and counter-contours on the two partial shafts, or on the module output shaft and the module input shaft of the shaft device of the external module.

[0047] Of course, the partial shafts can also be designed such that the second partial shaft has a cavity for receiving a shank end of the first partial shaft. The first partial shaft can then be inserted into the cavity of the second partial shaft to connect the partial shafts to each other so that they can perform a common rotary movement.

[0048] The mounting of the first partial shaft in the second partial shaft advantageously also enables axial mobility of the first partial shaft. According to the invention, it is preferred that the first partial shaft can move axially, for example, within a range of approximately 2 mm. In other words, the axial range of movement of the first shaft or the module output shaft is in a range of approximately 2 mm, whereby the movement of the first partial shaft or the module output shaft can be limited by stops within the external module. The axial range of movement of the first partial shaft of the shaft device of the external module is preferably somewhat greater than the axial stroke generated by the design and relative movement of the cam disks.

[0049] It is preferred according to the invention that the shaft device of the external module, in particular a second partial shaft, is connectable to a shaft device of the machine tool. The second partial shaft of the shaft device of the external module can preferably also be referred to as the module input shaft. The shaft device of the machine tool can in particular be a gearbox output shaft of the machine tool or the drilling rig. By connecting the module input shaft of the shaft device of the external module to the shaft device of the machine tool, a connection between the external module and the machine tool can advantageously be established. The connection between the shaft device of the machine tool and the shaft device of the external module is preferably made via a first interface.The first interface is particularly designed to connect the second partial shaft of the shaft device of the external module to the shaft device of the machine tool.

[0050] According to the invention, it is preferred that the housing of the external module be connectable to a housing of the machine tool. The external module has a housing, with one of the cam discs of the external module being firmly connected to the housing. This cam disc is preferably referred to as a housing-fixed or second cam disc. In the context of the present invention, the housing of the external module can preferably be referred to as an "external housing." The external housing can be axially connected to a housing of the machine tool. The machine tool can, for example, have a gear or motor housing, which is preferably a component of the housing of the machine tool.The connection between the external housing and the housing of the machine tool can, for example, be achieved via a housing interface, which advantageously provides an additional support function for the housing and can contribute to reducing the transmission of vibrations and impacts to the machine tool and thus to the user.

[0051] Within the meaning of the invention, it is particularly preferred that the housing of the external module is axially connected to the gear housing of the machine tool or can be connected to the gear housing of the machine tool. For example, the external module or its housing can be connected to the housing of the machine tool via a bearing, wherein this bearing is preferably designed to interact with the extension of the shaft device of the external module. In the context of the present invention, it is preferred that the axial or drilling forces that occur are generated by the operation of the machine tool and are increased by the additional impact movement that can be generated with the aid of the external module. Such an external module can be of particularly simple construction.

[0052] It is particularly preferred within the meaning of the invention that, when using the external module, both the module input shaft, i.e. the second partial shaft, of the shaft device is connected to the gearbox output shaft of the machine tool, and the external housing is axially connected to the gearbox housing of the machine tool. Both the connection of the shaft devices and the connection of the housings of the external module and the machine tool can each be effected via an interface, which within the meaning of the invention are preferably referred to as the first and second interfaces. The second interface can preferably also be referred to as the “housing interface”. Advantageously, this configuration of the connection between the external module and the machine tool can reduce the transmission of drilling forces to the handles of the machine tool. This protects the user and / orhis wrists are considerably protected and longer work with the proposed system consisting of an external module and a machine tool is possible. If the machine tool is a column-guided machine tool which is attached to a drill stand during operation, the invention can reduce the transmission of drilling forces to the drill stand. By reducing the transmission of drilling forces to the drill stand, the mechanical stability of the machine tool attachment can advantageously be prevented from being reduced, for example due to vibrations or the like. Furthermore, the proposed connection between the external module and the machine tool provides particularly effective protection for particularly sensitive components of the machine tool, such as bearings or roller bearings. This can advantageously extend the service life of the machine tool or its maintenance intervals.

[0053] It is preferred within the meaning of the invention that a bearing of the housing of the external module on the shaft device is designed as a floating bearing. Preferably, the external housing can be mounted on the second partial shaft of the shaft device via a floating bearing. It is preferred within the meaning of the invention that axial over-determination can be prevented by a floating bearing of the housing of the external module on the shaft device of the external module. In other words, a floating bearing of the external housing on the module input shaft of the external module can be provided in order to particularly effectively prevent axial over-determination and the transmission of excessive axial drilling forces to sensitive components of the machine tool. The machine tool can thus be protected from mechanical loads due to excessive stress.

[0054] It is preferred within the meaning of the invention that the shaft device of the external module comprises a first partial shaft and a second partial shaft, wherein the first partial shaft and the second partial shaft can be connected to one another via an interface. Preferably, the first partial shaft or the second partial shaft can be stationary in the axial direction, while the other partial shaft is movable in the axial direction. The other, non-stationary partial shaft of the external module, on the other hand, can move, in particular in the axial direction, i.e. away from the other partial shaft or towards the other partial shaft. However, it can be preferred within the meaning of the invention to provide stops which limit the mobility of the non-stationary partial shaft in order to prevent the unit from falling apart.

[0055] According to the invention, it is particularly preferred that the first cam disk is firmly connected to the first partial shaft of the external module. The first partial shaft is preferably arranged in a front region of the external module and can preferably also be referred to as the “module output shaft”. The first partial shaft can preferably be connected to a tool holder or a tool of the machine tool, so that the first partial shaft transmits the rotary movement of the machine tool or a torque to its tool. By interposing the external module, the rotary movement of the tool can be superimposed on the impact movement generated by the cam disks, so that a superimposed impact and rotary movement for the tool of the machine tool is advantageously obtained.In this exemplary embodiment of the invention, the first partial shaft preferably represents the non-stationary partial shaft of the external module, which can move in particular in the axial direction, i.e., away from or toward the other partial shaft. In this exemplary embodiment of the invention, the stationary partial shaft is the second partial shaft.

[0056] The second partial shaft can preferably also be referred to as a "module input shaft" within the meaning of the invention. The second partial shaft is preferably arranged in a rear region of the external module and can be connected to a shaft device of the machine tool. The shaft device of the machine tool preferably functions as a transmission output shaft and transmits the rotary motion of the machine tool motor to the shaft device of the external module or the second partial shaft of the shaft device of the external module. The shaft devices of the external module and the shaft device of the machine tool can be connected to one another, i.e., in particular, screwed, by means of a thread.For this purpose, for example, the second partial shaft of the shaft devices of the external module can have an internal thread which interacts with a correspondingly designed external thread of the shaft device of the machine tool in order to effect a screw connection between the shaft devices.

[0057] According to the invention, it is preferred that the interfaces are designed to transmit various torques that occur during operation of the machine tool. For example, a shaft interface can be provided, which is preferably arranged between the first shaft device and the second shaft device. This shaft interface can be designed to permit a preferably axial relative movement of the partial shafts of the module. This relative movement to be permitted between the partial shafts is preferably at least of the order of magnitude of the axial stroke, i.e. an amplitude of the impact movement. In other words, the partial shafts of the external module can move relative to one another at least to the extent that the cam disks of the module do in order to generate the impact movement. According to the invention, it is particularly preferred that the first cam disk («shaft-fixed») is arranged on the movable partial shaft.A key advantage of the interface or the design of the shaft device consisting of two partial shafts is that those components of the machine tool that are arranged on the stationary partial shaft cannot move relative to other gear components in the axial direction. This can significantly reduce wear on components that are subject to particular stress. Furthermore, the provision of the interface or the two-part design of the shaft device means that the gear teeth of the gears used no longer need to be straight-toothed. Instead, helical-toothed gears can now be used, which advantageously increases flexibility in selecting the gears. Furthermore, the helical gearing can achieve improved smoothness and increased strength.

[0058] The functioning of the microhammering function is preferably determined primarily by the two cam discs. The microhammering function is based in particular on the fact that the cam discs can be in engagement with one another with their axial end faces, whereby the cam discs preferably rotate simultaneously relative to one another about a common central axis. Within the meaning of the invention, it is preferred that curved contours that can engage with one another are located on the axial end faces of the cam discs. These curved contours can, for example, comprise ramp-shaped structural elements in which an inclined plane connects a lowest and a highest point. Within the meaning of the invention, the structural elements can preferably also be referred to as "curves."The kinematics of the cam disks are preferably composed of at least a first and a second part, wherein the first part can be assigned to a first state and the second part to a second state of the cam disk system. In the first state, the two cam disks are in contact with one another, while in a second state the cam disks are spaced from one another. Depending on the operating point of the cam disk system, one or the other state predominates. The operating point of the cam disk system preferably depends on the rotational speed and / or the feed force. In the first state of the cam disk system, an axial compressive force can advantageously be transmitted between the cam disks, so that the axial movement of the cam disks relative to one another follows or mirrors the contours or structural elements on the axial end faces of the cam disks.This leads, for example, to the cam discs rubbing against each other. In the second state of the cam disc system, the cam discs can at least temporarily or partially lift off from each other, i.e. they are spaced apart from each other ("spaced apart"). In this second state, advantageously no axial force is transmitted. The first state of the cam disc system preferably occurs when the contact surfaces of the cam discs are located on a part of the cam disc with a positive gradient. Such a part of the cam disc with a positive gradient can preferably also be referred to as a "rising region of the cam disc" or as an "inclined plane of a structural element" within the meaning of the invention.

[0059] As soon as the contact surfaces of the cam discs have passed an apex or highest point of the curves and the curve gradient changes from the positive to a negative range, the cam discs can lift off from one another so that a distance exists between the cam discs. This happens especially when the relative rotational speed of the cam discs is high and the feed force is low. In the context of the present invention, states of the cam disc system are therefore also conceivable in which the first part of the kinematics takes up 100% or essentially 100% of the overall kinematics, i.e. the cam discs are completely or essentially completely in the first state. In this first state, the cam discs are preferably at least partially in contact with one another and in particular do not lift off from one another.

[0060] A further aim of the invention is to ensure long-term functionality of the cam disk system. In particular, in the context of the present invention, wear on the cam disks is to be reduced. This can preferably be achieved by applying a load-bearing film comprising a lubricant ("lubricating film") to the cam disks, preferably permanently. The lubricant can preferably be applied to the axial end faces and / or to the cam contours or the structural elements. The lubricant can preferably be special lubricating greases or the like. Within the meaning of the invention, it is preferred that the lubricating film is located between the cam surfaces of the cam disks. The lubricating film is preferably designed to enable the cam disks to slide against one another when the cam disks are in contact with one another (first state).In this way, undesired wear on the cam discs can advantageously be considerably reduced. Tests have shown that the lubricating film between the cam discs also helps to prevent wear during the transition from the second state to the first state. The transition from the second state to the first state is characterized in particular by the cam discs meeting one another again with the creation of a ("hammer") blow, i.e. after a phase of lifting off (second state), they come into contact with one another again (first state). This hammer blow preferably occurs when a region of the first cam discs has moved along an inclined plane of a structural element of the second cam disc and the region of the first cam discs reaches the end or a highest point of the structural element of the second cam disc and then falls back to the lowest level of the second cam disc.This lowest level preferably comprises the lowest points of the cam disc, which in the sense of the invention are preferably also referred to as “curve valleys”.

[0061] In order to maintain the lubricating film during operation of the machine tool or the cam disk system and to avoid "dry running", it is preferred according to the invention to provide at least one lubricant reservoir in the cam disk system. As a result, lubricant that is displaced from the intermediate or contact area of ​​the cam disks by the relative movement of the cam disks can be replaced, preferably continuously or essentially continuously, so that the lubricating film can be maintained during operation of the machine tool or the cam disk system. It is preferred according to the invention that lubricant can flow from the lubricant reservoir into the intermediate or contact area of ​​the cam disks.Since the lubricant forming the lubricating film is transported predominantly in the area of ​​the outer diameter of the cam discs due to centrifugal forces, the inventors have recognized that it is advantageous to provide the at least one lubricant reservoir in spatial proximity to the inner diameter of the cam discs, so that the lubricant wets essentially the entire area in the intermediate region between the cam discs on its way toward the outer diameter. It is preferred within the meaning of the invention to provide a series of lubricant reservoirs, whereby the lubricant reservoirs can also preferably be referred to as "grease pockets" within the meaning of the invention.

[0062] To achieve an even better and more even distribution of the lubricating film, it has proven advantageous to provide grease pockets in the contact area between the cam discs. This creates an even more homogeneous and therefore more load-bearing lubricating film. To achieve a long service life for the cam disc system and the individual cam discs, arranging the grease pockets in the area of ​​the curve valleys on the cam discs has proven to be effective. This is particularly true because these valley areas are exposed to relatively low mechanical loads, such as pressure. This can be explained in particular by the fact that the cam discs often skip over these valley areas during the transition from the second to the first state and thus hardly touch them.In a further advantageous embodiment of the invention, a larger lubricant reservoir can be provided in the region of the inner diameter of the contact area of ​​the cam disks of the cam disk system, from which the individual grease pockets are fed. This can be achieved, for example, by fluidly connecting the larger lubricant reservoir to the individual grease pockets. Through this connection, the lubricant from the larger lubricant reservoir in the region of the inner diameter of the cam disk system can flow into the individual grease pockets, thus contributing to the formation of the lubricating film between the cam disks.

[0063] According to the invention, it is preferred that an angular width A2° of the grease pockets be smaller than an angular width A1° of a curve or a structural element of a cam disk. From this, the relationship A2° < A1° can be derived. In particular, the at least one grease pocket can be located in a curve valley of the cam disk, wherein the angular width A2° of the grease pocket can be of the order of magnitude of the range that is skipped by the opposing cam disk in the second movement state of the cam disks and is therefore subjected to only a small amount of mechanical stress.

[0064] In a further advantageous embodiment of the invention, the at least one grease pocket can be located in a curve valley and its angular width A2° can be less than half the angular width A1° of a curve of the cam disk, so that A2° < 0.5 • A1° applies.

[0065] The grease pockets can also have a depth T, with the depth T of at least one grease pocket being in the range of millimeters. For example, a depth T can be in the range of 2 mm. One possible shape of a grease pocket is shown in Figure 6. Of course, many other suitable shapes and configurations of the grease pockets are also conceivable.

[0066] In the context of the present invention, a machine tool with a tool is disclosed, wherein the tool of the machine tool is designed to execute a rotary movement. The terms, definitions, and technical advantages introduced for the external module and the system preferably apply analogously to the machine tool. The machine tool is configured to generate an impact movement, wherein the machine tool comprises a first cam disk and a second cam disk, wherein the first cam disk is connected to a shaft device of the machine tool ("shaft-fixed") and the second cam disk is fixedly connected to a housing of the machine tool ("housing-fixed"), wherein the first cam disk and the second cam disk interact to generate the impact movement, wherein the machine tool is designed to superimpose the impact movement on the rotary movement of the tool of the machine tool.The shaft device of the machine tool to which the first cam disk can be connected can preferably also be referred to as the transmission output shaft of the machine tool within the meaning of the invention. In other words, the first cam disk can be mounted on the shaft device or on the transmission output shaft of the machine tool. It is preferred within the meaning of the invention that in this case, the entire shaft device can preferably move within the scope of the microhammering movement.

[0067] According to the invention, it is preferred that the shaft device of the machine tool comprises a first partial shaft and a second partial shaft, wherein the first partial shaft and the second partial shaft can be connected to one another via an interface. The interface is preferably designed to connect the first and the second partial shaft of the shaft device of the machine tool to one another. The interface is therefore preferably also referred to as a “shaft interface”. Preferably, the first partial shaft or the second partial shaft can be designed to be stationary in the axial direction, while the other partial shaft is designed to be movable in the axial direction. According to the invention, this preferably means that a bearing arrangement is provided within the machine tool for the radial and / or axial positioning or fixing of the shaft device or the output shaft.This bearing arrangement can preferably be designed as a fixed-Z-loose bearing arrangement or as a bearing arrangement in an X- or O-arrangement. Due to the shaft interface, the output-side partial shaft, in particular, is preferably axially movable. In this embodiment, the output-side partial shaft is, in particular, the second partial shaft of the machine tool.

[0068] The other, non-stationary partial shaft of the machine tool can, however, move, in particular in the axial direction, i.e. away from or towards the other partial shaft. However, it may be preferable within the meaning of the invention to provide stops which restrict the mobility of the non-stationary partial shaft in order to prevent the shaft from falling apart. In addition, the machine tool has one or more gears which are preferably also arranged on the stationary partial shaft of the machine tool. Within the meaning of the invention, it is preferable that the partial shafts of the shaft device are always designed to execute a rotary movement, while the axial mobility of the partial shafts of the shaft device can be partially restricted.According to the invention, it is preferred that the interface is configured to transmit various torques occurring during operation of the machine tool to the tool of the machine tool. Furthermore, the interface is designed to permit a preferably axial relative movement of the sub-shafts of the machine tool. This permissible relative movement between the sub-shafts of the machine tool is preferably at least of the order of magnitude of the axial stroke, i.e., an amplitude of the impact movement. In other words, the sub-shafts of the machine tool can move relative to one another at least to the extent that the cam disks of the machine tool do in order to generate the impact movement.

[0069] According to the invention, it is preferred that the first cam (“shaft-fixed”) be arranged on the movable part of the shaft. During operation of the machine tool, only the movable part of the machine tool's transmission output shaft moves, preferably within the scope of the axial stroke of the impact movements, which can be superimposed on the pure rotary movement of the machine tool.

[0070] A key advantage of the interface, or preferably the two-part design of the shaft device of the machine tool, is that those components of the machine tool arranged on the axially stationary partial shaft do not exhibit any relative speed with respect to other transmission components of the machine tool. This can significantly reduce wear on components subject to particularly high loads. Furthermore, the proposed design of the machine tool with an interface, or with a division of the shaft device of the machine tool or the transmission output shaft of the machine tool into two partial shafts, eliminates the need for the toothing of the gears used to be straight-toothed.Rather, helical gears can now also be used, which advantageously increases flexibility in gear selection. This can, in particular, improve smooth running and strength. Further advantages emerge from the following description of the figures. The figures, the description, and the claims contain numerous features in combination. Those skilled in the art will expediently consider the features individually and combine them into further meaningful combinations.

[0071] In the figures, identical and similar components are numbered with the same reference numerals. They show:

[0072] Fig. 1 schematic view of a preferred embodiment of the system comprising an external module and a machine tool

[0073] Fig. 2 schematic view of a preferred embodiment of the contact area between external module and machine tool

[0074] Fig. 3 Side view (top) and top view (bottom) of a preferred embodiment of a cam disc and its surface

[0075] Fig. 4 Graphic explanations of the possible design of a surface of a cam disc and the structural elements

[0076] Fig. 5 schematic side view of a machine tool with an integrated solution for generating an impact movement, wherein the machine tool has a shaft interface

[0077] Fig. 6 Top view of a preferred embodiment of a cam disc (left) and sectional view of a grease pocket and representation of its depth T (right)

[0078] Implementation examples and figure descriptions:

[0079] Figure 1 shows a schematic view of a preferred embodiment of the system 50 comprising the external module 10 and the machine tool 100. The central region of Figure 1 shows the external module 10, which can be arranged between the machine tool 100 and the tool 102 of the machine tool 100. The tool 102 of the machine tool 100 can be connected to the machine tool 100 via a tool holder 118. In the exemplary embodiment shown in Figure 1, the external module 10 is arranged in particular between the tool holder 118 and the machine tool 100. The machine tool 100 can preferably be a drilling device or a core drilling device; the tool 102 of the machine tool 100 can, for example, be designed as a drill bit. The machine tool 100 has a motor (122, see Fig.5), wherein the tool 102 of the machine tool 100 can be driven via a shaft device 104 of the machine tool 100. In particular, the motor 122 of the machine tool 100 generates a rotary motion D that can be transmitted to the tool 102 of the machine tool 100. The shaft device 104 of the machine tool 100 can preferably also be referred to as a transmission output shaft 104.

[0080] The present invention relates to an external module 10 with which the rotary movement D of the tool 102 of the machine tool 100 can be superimposed with an impact movement S. The impact movement S can advantageously be generated with the external module 10. The impact movements S, with which the pure rotary movement D of the machine tool 100 can be superimposed, are preferably also referred to as "microhammering." In other words, a microhammering function for a machine tool 100 can be provided with the external module 10. The technical solution presented here relates to the generation of the impact movements S by an external module 10, whereas in conventional machine tools 100, as known from the prior art, integrated solutions are often used in which the impact movements S are generated within the machine tool 100 itself.

[0081] The external module 10 can be "interposed" like an adapter between the tool 102 and the machine tool 100. The external module 10 has a first cam disk 12 and a second cam disk 14, wherein the first cam disk 12 is designed to be shaft-fixed, i.e. connected to a shaft device 16 of the external module 10. The second cam disk 14 is preferably designed to be housing-fixed. In the sense of the invention, this preferably means that the second cam disk 14 is connected to a housing 18 of the external module 10. Thus, the first cam disk 12 is able to rotate, specifically together with the shaft device 16 of the external module 10, while the second cam disk 14 is not designed to rotate. The first cam disk 12 is designed to be axially movable during operation of the machine tool 100 in order to generate the axial stroke or the impact movement S.The second cam 14 is not movable in the axial direction during operation of the machine tool 100. Preferably, the first cam 12 is capable of being pushed off the second cam 14 to generate the axial stroke or impact movement S. In the context of the invention, this preferably means that the first cam 12 of the external module 10 can move in the spatial directions "forward" and "backward."

[0082] The spatial directions are illustrated in Figure 1 with a directional cross. The spatial direction "forward" is designated by the letter "V," while the spatial direction "backward" is designated by the letter "H," the spatial direction "upward" by the letter "O," and the spatial directions "downward" by the letter "U." The tool 102 of the machine tool 100 is therefore arranged in a front region of the machine tool 10, while the machine tool 100 is depicted behind the external module 10 in Figure 1. When the first cam disk 12 of the external module 10 moves, the shaft device 16 of the external module 10 preferably also moves with it, since the first cam disk 12 is firmly connected to the shaft device 16 of the external module 10. According to the invention, it is preferred that the second cam disk 14 and the housing 18 of the external module 10 cannot move relative to the machine tool 100 during operation.

[0083] The two cam disks 12, 14 each have at least one structural element 20 (see Figures 3 and 4), wherein the structural elements 20 are configured to generate the impact movements S when the cam disks 12, 14 move relative to one another during operation of the machine tool 100. By providing the structural elements 20 on both cam disks 12, 14, high surface pressures are advantageously avoided. The structural elements 20 can, for example, be designed in a ramp-like manner, wherein a movement of one cam disk, for example the first cam disk 12, follows the height profile of the structural elements 20 of the other cam disks - for example the second cam disk 14 - when the cam disks 12, 14 execute a rotational relative movement. It is preferred within the meaning of the invention that, in particular, the first cam disk 12 rotates while the second cam disk 14 remains stationary.The standstill of the second cam disc 14 and the movement of the first cam disc 12 at a first rotational speed advantageously results in a relative movement of the cam discs 12, 14. Due to the drilling pressure with which the machine tool 100 is pressed onto the surface to be machined, the cam discs 12, 14 are axially pressed together or onto one another during their relative movement. In this way, the cam discs 12, 14 are predominantly in close contact with one another and slide up or down from one another depending on the geometry or nature of the surfaces 36 of the cam discs 12, 14, thus generating the impact pulse or impact movement.

[0084] At the end of the ramp or of the structural element 20, the first cam disk 12 falls back onto the subsequent ramp of the cam disk 14, thereby generating an impact movement S. In particular, an axial stroke is generated by the falling of the first cam disk 12. The axial stroke can preferably correspond to a distance, wherein the distance can, for example, correspond to the height of a ramp, i.e., of a structural element 20. If several structural elements 20 are provided on the cam disks 12, 14, an alternating axial stroke can occur. In the sense of the invention, this preferably means that impact movements S are generated in rapid succession, which then form the micro-hammering function for the machine tool 100.

[0085] The external module 10 can comprise an interface 30, wherein the interface 30 is configured to connect a first partial shaft 32 and a second partial shaft 34 of the shaft device 16 of the external module 10 to one another. In the exemplary embodiment of the invention illustrated in Figure 1, the first, shaft-fixed cam disk 12 is connected in particular to the first partial shaft 32 of the shaft device 16 of the external module 10. The interface 30 can preferably also be referred to as a “shaft interface.” One of the two partial shafts 32, 34, i.e. the first partial shaft 32 or the second partial shaft 34, can be stationary in the axial direction, while the respective other partial shaft (34 or 32) is movable in the axial direction. In other words, one of the partial shafts 32, 34 can be displaced in a forward-backward direction, while the other partial shaft 34, 32 is stationary.

[0086] In integrated solutions (see Figure 5), the machine tool 100 can also have an interface 108 for connecting the partial shafts 110, 116, wherein the interface 108 is configured to connect a first partial shaft 110 and a second partial shaft 116 of the shaft device 124 of the machine tool 100 to one another. In such an integrated solution, the first partial shaft 110 or the second partial shaft 116 can be stationary in the axial direction, while the other partial shaft 116, 110 is movable in the axial direction. In an integrated solution, the machine tool 100 can comprise two cam disks 112, 114, wherein the first cam disk 112 is connected to the shaft device 124 of the machine tool 100 and the second cam disk 114 is connected to the housing 106 of the machine tool 100.Preferably, the first cam disc 112 can be connected to the first partial shaft 110 of the shaft device 104 of the machine tool 100. It is preferred within the meaning of the invention that the first cam disc 112 is arranged on the axially movable partial shaft (110 or 116), wherein the first partial shaft 110 of the shaft device 124 of the machine tool 100 is preferably movable.

[0087] As can be seen from Figure 1, the second partial shaft 34 of the shaft device 16 of the external module 10 can represent an extension of the shaft device 16. The housing 18 of the external module 10 can be mounted on this second partial shaft 34 of the shaft device 16, wherein the bearing 24 is designed in particular as a floating bearing. The second partial shaft 34 of the shaft device 16 of the external module 10 is preferably also referred to as a "gearbox output extension" within the meaning of the invention, since from another perspective it also represents an extension of the shaft device 104 of the machine tool 100 into the external module 10. The second partial shaft 34 can be connected to the shaft device 104 of the machine tool 100 so that the rotary movement D of the machine tool 100 can be transmitted to the tool 102 of the machine tool 100 via the shaft devices 16, 104.

[0088] The impact movement S, which can be superimposed on the rotational movement D of the tool 102 of the machine tool 100, can advantageously be switched on and off by moving the cam disks 12, 14 apart in the axial direction such that there is no longer any contact between the cam disks 12, 14. This pulling apart of the cam disks 12, 14 can be achieved, for example, by moving the first cam disk 12 away from the second cam disk 14. The first cam disk 12 can be in a first position before being moved away and in a second position after being moved away, wherein the first cam disk 12 can be fixed in a second position with a fastening element 26. According to the invention, it is preferred that the cam disks 12, 14 be moved apart by actuating a movement thread. A fastening element 26 can then be provided to fix the thread in the desired position.

[0089] The cam disks 12, 14 can also be moved apart by moving the second cam disk 14 away from the first cam disk 12. The second cam disk 14 can be displaced relative to the housing 18 of the external module 10 by an actuating element 28. Due to the connection between the second cam disk 14 and the housing 18 of the external module 10, the second cam disk 14 can be displaced relative to the machine tool 100, in particular together with the housing 18 of the external module 10.

[0090] Figure 2 shows a schematic view of a preferred embodiment of the contact area between external module 10 and machine tool 100. The external module 10 can be connected to the machine tool 100 on its rear side, while the external module 10 can be connected to the tool holder 118 or the tool 102 of the machine tool on its front side. To connect the external module 10 to the machine tool 100, at least two interfaces 52, 54 can be provided, wherein the first interface 52 is configured to connect the shaft device 16 of the external module 10 to a shaft device 104 of the machine tool 100, while the second interface 54 is configured to connect the housing 18 of the external module 10 to a housing 106 of the machine tool 100.It is preferred in the sense of the invention that, with the first interface 52, in particular the second partial shaft 34 of the shaft device 16 of the external module 10 (“module input shaft”) can be connected to the shaft device 104 of the machine tool 100.

[0091] In particular, the housing 18 of the external module 10 can be connected to the housing 106 of the machine tool 100. Furthermore, the second partial shaft 34 of the shaft device 16 of the external module 10 can be connected to the shaft device 104 of the machine tool 100. Contact points or contact areas between the external module 10 and the machine tool 100 thus exist in particular in the area of ​​the housings 18, 106 of the external module 10 ("second interface 54") and the machine tool 100 and in the area of ​​the shaft devices 16, 104 ("first interface 52"). The first interface 52 and the second interface 54 between the machine tool 100 and the external module 10 are illustrated in particular in Figure 2.

[0092] Figure 2 shows different load paths LP1, LP2, which show possible courses of the force flow within the external module 10. The upper, first load path LP1 is a possible load path that the force flow can take within the external module 10. The lower, second load path LP2 is the preferred load path, in which the force flow is introduced into the housing 106 of the machine tool 100. This allows sensitive components within the machine tool 100 to be better protected than with load path LP1, in which the force can be introduced into the shaft devices 16, 104 of the external module 10 or the machine tool 100. This can, for example, damage bearings or rolling bearings.

[0093] Figure 3 shows a side view and a top view of a preferred embodiment of a cam disk 12, 14 and its surface 36. Structural elements 20 can be provided on the surface 36 of the cam disks 12, 14, wherein a number of the structural elements 20 is designated by the reference symbol "N". For example, in the side view of a cam disk 12, 14 shown in the upper region of Figure 3, six complete structural elements 20 are shown. The structural elements 20 in the embodiment of the invention shown in Figure 3 are designed as ramps that comprise an inclined plane 38 (see Figure 4) and are characterized by a height difference Ah between the lowest point 40 and the highest point 42 of the ramp 20 (see Figure 4). For example, the cam disk 12, 14 shown in Figure 3 has seventeen structural elements 20, so that N = 17.In the lower part of Figure 3, a plan view of a surface 36 of the cam disc 12, 14 is shown.

[0094] Figure 4 shows graphic explanations of the possible design of a surface 36 of a cam disk 12, 14 and of the structural elements 20. According to the invention, it is preferred that the structural elements 20 are arranged uniformly on the circumference of the cam disk 12, 14. The length of the inclined plane 38 is preferably the same or similar for such uniformly arranged structural elements 20. However, according to the invention, it can also be preferred that the structural elements 20 are not arranged uniformly on the circumference of the cam disk 12, 14. The inclined planes 38 of the structural elements 20 can then have different lengths. According to the invention, it is preferred that the heights Ah of the structural elements 20 are each the same or similar. The height difference Ah can, for example, be in a range of 0.5 mm.

[0095] The upper section of Figure 4 shows, by way of example, a developed view of the profile of a cam disk 12, 14 with seventeen structural elements 20, wherein the structural elements 20 are distributed over the full circle (360°) of the cam disk 12, 14. The lower section of Figure 4 shows, by way of example, a side view of a possible embodiment of a structural element 20. The structural element 20 has an inclined plane 38 which extends between a lowest point 40 and a highest point 42 of the structural element 20. The structural element 20 shown at the bottom in Figure 4 is, for example, ramp-shaped, wherein a height difference Ah between the lowest point 40 and the highest point 42 of the structural element 20 can be, for example, in a range of 0.5 mm.Figure 5 shows a side view of a possible embodiment of a machine tool 100 with an integrated solution for generating an impact movement S, wherein the machine tool 100 has a shaft interface 108. Figure 5 shows, in particular, a machine tool 100 in which the microhammering function is generated or provided within the machine tool 100 itself. For this purpose, the machine tool 100 comprises a first cam disk 112 and a second cam disk 114, which are designed and constructed in accordance with the embodiments for the cam disks 12, 14 of the external module 10. The cam disks 112, 114 of the machine tool 100 are also configured to interact in the same way to generate impact movements S and / or impact pulses, so that the machine tool 100 shown in Figure 5 as such is capable of providing a microhammering function.The machine tool 100 depicted in Figure 5 comprises a housing 106 and two shaft devices 104, 124. The shaft device 104 preferably corresponds to a rotor shaft of the motor 122 of the machine tool 100. The further shaft device 124 corresponds functionally to the shaft device 16 of the external module 10, whereby the further shaft device 124 can also comprise two partial shafts 110, 116. Furthermore, the machine tool 100 can comprise a handle 120 with which a user can hold and guide the machine tool 100. The machine tool 100 can comprise a gear mechanism, so that a further shaft device 124 of the machine tool 100 does not necessarily have to be directly connected to the motor 122 of the machine tool 100.For example, gears or other shaft devices (not shown) may be provided between the shaft devices 104, 124 and the motor 122 of the machine tool 100, for example, to adjust a rotational speed of the motor 122. Preferably, the transmission of the machine tool 100 may be configured to reduce a high rotational speed of the motor 122 so as to obtain a rotational speed suitable for drilling for the tool 102 of the machine tool 100. The shaft devices 104, 124 of the machine tool 100 may be arranged offset from one another in an upward-downward direction, wherein the shaft devices 104, 124 of the machine tool 100 are preferably oriented substantially parallel to one another.

[0096] In the machine tool 100 shown in Figure 5, the shaft device 104 is configured to interact with the further shaft device 124, which, if the microhammering function is provided by an external module 10, corresponds to the shaft device 16 of the external module 10. This further shaft device 124 can preferably comprise a first partial shaft 110 and a second partial shaft 116, wherein the first partial shaft 110 corresponds functionally to the first partial shaft 32 of the external module 10 and the second partial shaft 116 corresponds functionally to the second partial shaft 34 of the external module 10. Even in the integrated solution, in which the microhammering function is provided by the machine tool 100 itself and which is depicted in Figure 5, an interface 108 is provided for connecting the two partial shafts 110 and 116.The objects marked with a cross in Figure 5 can preferably be bearings or rolling bearings that enable an axial movement of the first partial shaft 110 and the first cam disk 112 attached thereto, so that the machine tool 100 can generate an impact movement S or provide a microhammering function.

[0097] Figure 6 shows on the left side a preferred embodiment of a cam disk 12, 14, and on the right side a sectional view of a grease pocket 130 and its depth T. The left part of Figure 6 shows structural elements 20 and grease pockets 130 on an upper side of a cam disk 12, 14. The structural elements 20 can also be referred to as "curves" within the meaning of the invention. The curves 20 or structural elements 20 have an angular width A1°, while the grease pockets 130 have an angular width A2°. On the right side of Figure 6, a sectional view through a grease pocket 130 is shown, wherein the grease pocket 130 has the depth T.As can be seen from Figure 6, the grease pockets 130 can be arranged in particular in the region of a "valley" of the cam disk 12, 14, whereby these valley regions, which are subject to low mechanical loads, can preferably coincide with the lowest points 40 of the cam disks 12, 14 and are preferably located directly next to the highest points 42 of the cam disks 12, 14. As a result, the cam disks 12, 14 usually do not touch each other in these valley regions 40, as the cam disks 12, 14 jump over this valley region 40, so that this is a good location for the grease pockets 130. Figure 6 shows one possible shape and configuration of two grease pockets 130. Of course, the grease pockets 130 can also have any other suitable shape and configuration. In the interior region of the cam disk 12, 14, a larger lubricant reservoir 132 can be present, which is in fluid communication with the individual grease pockets 130.Advantageously, the individual grease pockets 130 can be fed from the larger lubricant reservoir 132 and draw lubricant from this larger lubricant reservoir 132. In the exemplary embodiment of the cam disks 12, 14 shown in Figure 6, the grease pockets 130 are arranged near the inner region of the cam disks 12, 14, so that the grease pockets 130 are also located in spatial proximity to the larger lubricant reservoir 132 and the lubricant from the larger lubricant reservoir 132 can flow particularly easily into the individual grease pockets 130 in the region of the cam valleys 40 of the cam disks 12, 14. Because the lubricant is distributed from the inside to the outside due to the centrifugal forces acting upon rotation of the cam discs 12, 14, the arrangement of the grease pockets 130 in the interior of the cam discs 12, 14 and particularly good wetting of the surfaces 36 and 37 can ensure that the lubricant is distributed from the inside to the outside.The end faces of the cam discs 12, 14 can be coated with lubricant. This allows a particularly homogeneous lubricant film to be provided, which advantageously counteracts the occurrence of wear particularly effectively.

[0098] List of reference symbols

[0099] 10 external module

[0100] 12 first cam disc

[0101] 14 second cam disc

[0102] 16 Shaft device of the external module

[0103] 18 External module housing

[0104] 20 structural elements

[0105] 24 Storage of the external module housing

[0106] 26 Fastening element

[0107] 28 Actuating element

[0108] 30 Interface

[0109] 32 first partial shaft, module output shaft

[0110] 34 second partial shaft, module input shaft

[0111] 36 Surface of a cam disc

[0112] 38 inclined plane of a structural element

[0113] 40 lowest point of a structural element

[0114] 42 highest point of a structural element

[0115] 50 System comprising a machine tool and an external module

[0116] 52 first interface

[0117] 54 second interface

[0118] 100 machine tools

[0119] 102 Machine tool tool

[0120] 104 Shaft device of the machine tool

[0121] 106 Machine tool housing 108 Interface for connecting the partial shafts

[0122] 110 first partial wave

[0123] 112 first cam of the machine tool

[0124] 114 second cam of the machine tool

[0125] 116 second partial wave

[0126] 118 Tool holder of the machine tool

[0127] 120 Machine tool handle

[0128] 122 Machine tool motor

[0129] 124 additional shaft devices

[0130] 130 fat pocket

[0131] 132 larger lubricant reservoir

[0132] S striking movement

[0133] D rotational movement

[0134] Ah height difference of the structural elements

[0135] N Number of structural elements

[0136] V front, front, spatial view “forward”

[0137] H rear, back or rear, room viewing “to the rear”

[0138] U bottom, bottom, room view “downwards”

[0139] O top, top side, room view “upwards”

[0140] LP1 Load path 1

[0141] LP2 Load path 2

[0142] A1 ° Angular width of a curve of a cam disk

[0143] A2° Angular width of a fat pocket

[0144] T Depth of a fat pocket

Claims

Patent claims 1. System (50) comprising a machine tool (100) and an external module (10) for generating a percussive movement S, wherein a tool (102) of the machine tool (100) is configured to perform a rotary movement D, characterized in that the machine tool (100) and the external module (10) are connected to each other via a first interface (52) and a second interface (54), wherein the first interface (52) is configured to connect the shaft device (16) of the external module (10) to a shaft device (104) of the machine tool (100) and the second interface (54) is configured to connect the housing (18) of the external module (10) to a housing (106) of the machine tool (100).

2. System (50) according to claim 1 characterized in that the external module (10) comprises a first cam disk (12) and a second cam disk (14), wherein the first cam disk (12) is connected to a shaft device (16) of the external module (10) and the second cam disk (14) is fixedly connected to a housing (18) of the external module (10), wherein the first cam disk (12) and the second cam disk (14) cooperate to generate the impact movement S, wherein the external module (10) is configured to superimpose the rotary movement D of the tool (102) of the machine tool (100) with the impact movement S.

3. System (50) according to claim 2 characterized in that the first cam disk (12) and the second cam disk (14) each have at least one structural element (20) such that an alternating axial stroke is generated during a relative movement of the first cam disk (12) and the second cam disk (14).

4. System (50) according to one of the preceding claims characterized in that the shaft device (16) of the external module (10) comprises a first partial shaft (32) and a second partial shaft (34) comprises the first partial shaft (32) and the second partial shaft (34) being connectable to each other via an interface (30).

5. System (50) according to claim 4 characterized in that the first partial shaft (32) or the second partial shaft (34) is designed to be fixed in the axial direction, while the other partial shaft (34, 32) is designed to be movable in the axial direction.

6. System (50) according to claim 4 or 5 characterized in that the first cam disk (12) is arranged on the movable partial shaft (32 or 34).

7. System (50) according to one of claims 4 to 6 characterized in that the external module (10) can be connected to the machine tool (100) via the first partial shaft (32) or the second partial shaft (34).

8. System (50) according to one of the preceding claims characterized in that the impact movement S has a higher frequency than the rotary movement D of the machine tool (100) and / or its tool (102).

9. System (50) according to one of the preceding claims characterized in that the first cam disk (12) and / or the second cam disk (14) has / have at least one lubricant reservoir (130), wherein the at least one lubricant reservoir (130) has an angular width A2° which is smaller than an angular width A1° of a structural element (20) of the cam disks (12, 14).

10. System (50) according to one of the preceding claims characterized in that the first interface (52) is configured to transmit a torque, and The second interface (54) is configured to transmit a force acting in the axial direction. System (50) according to one of the preceding claims, characterized in that the impact movement S, with which the rotary movement D of the tool (102) of the machine tool (100) can be superimposed, can be switched on and off by moving the cam disks (12, 14) apart in the axial direction so that there is no longer any contact between the cam disks (12, 14). System (50) according to claim 11, characterized in that the cam disks (12, 14) are moved apart by displacing the first cam disk (12) from the second cam disk (14). System (50) according to claim 12, characterized in that the first cam disk (12) can be fixed in a second position with a fastening element (26).System (50) according to claim 11, characterized in that the cam disks (12, 14) are moved apart by displacing the second cam disk (14) from the first cam disk (12). System (50) according to claim 14, characterized in that the second cam disk (14) together with the housing (18) of the external module (10) is displaceable relative to the machine tool (100).

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