EP3820649B1 - Torque screwdriver arrangement and method for operating a torque screwdriver arrangement of this kind - Google Patents

Description

The present invention relates to a torque wrench arrangement with a screwdriver housing, a drive train arranged in the screwdriver housing, which has a drive housing, a motor arranged in the drive housing, in particular an electric motor, and an output shaft which protrudes from the drive housing on its axially front end face and its axial front end comprises a bit holder for fixing a screw bit or can be connected to one in a rotationally fixed manner, and a torque measuring device. In addition, the present invention relates to a method for operating a torque wrench assembly.

Torque wrench assemblies for tightening and loosening screws are well known. Such torque wrench arrangements are increasingly provided with a torque measuring device for detecting the screw tightening torque. For example, the reveals EP 2 127 812 A1 a torque wrench assembly with a screwdriver housing and a drive train arranged in the screwdriver housing. The drive train comprises a drive housing, an electric motor arranged in the drive housing with an output shaft, a gearbox also arranged in the drive housing and connected to the electric motor via its output shaft, and an output shaft of the gearbox, which protrudes from the drive housing on its axially front end face and its axial front end via a coupling mechanism with a bit holder for fixing a screw bit can be connected in a rotationally fixed manner. In addition, the torque wrench assembly includes the EP 2 127 812 A1 a torque measuring device which is arranged in the axial direction of the drive train between the electric motor and the transmission. Specifically, in the area of the drive housing that surrounds the output shaft of the electric motor, strain gauges are applied to the outside of the drive housing, by means of which the screw tightening torque can be detected. As soon as the detected screw tightening torque reaches a predetermined value, the electric motor can be stopped accordingly. In addition, the area of the drive housing that surrounds the electric motor is firmly connected to the screwdriver housing. In this way, the reaction torque exerted on the drive housing is supported over a large area during operation of the torque wrench arrangement. Using the torque wrench assembly EP 2 127 812 A1 This means that only a very inaccurate measurement of the output and/or reaction torque is possible.

From the GB 2 108 272 A a torque wrench assembly according to the preamble of claim 1 is disclosed.

Against this background, the present invention is based on the object of providing a torque wrench arrangement of the type mentioned at the outset, which enables the output torque of the output shaft to be recorded as precisely as possible and is also inexpensive to manufacture and operate.

This object is achieved according to the invention in a torque wrench arrangement according to claim 1.

The invention is therefore based on the idea of supporting a reaction torque exerted on the drive housing at exactly one support point between the drive housing and the screwdriver housing via a support arrangement and otherwise providing the drive housing in the screwdriver housing so that it can rotate in particular about a longitudinal axis of the drive train. During operation of the torque wrench arrangement according to the invention, the output torque occurring on the output shaft is transmitted from the output shaft via a drive mechanism and the drive housing of the drive train to the support arrangement, where it can be detected as reaction torque. For example, the output torque is converted into a measurable rotational deflection of the support arrangement. Detecting the reaction torque is convenient because it is particularly important to measure the rotating output shaft, which is often associated with problems. can be dispensed with. The torque measuring device can be connected to or attached to the support arrangement. In principle, it is also possible for the support arrangement to include at least part of the torque measuring device. By detecting the reaction torque directly at the support arrangement and thus at the only support point of the reaction torque, the output torque of the output shaft can be detected much more precisely via the reaction torque compared to the previously known torque screwdriver arrangement. In addition, the torque wrench arrangement according to the invention can be manufactured and operated cost-effectively. In addition, the torque detection according to the invention on the support arrangement offers the advantage of increased measurement accuracy and the possibility of measuring higher speeds compared to torque detection by detecting the motor current.

According to one embodiment of the invention, the support arrangement is arranged between an axial end of the drive housing, preferably an axial end face of the drive housing, and the screwdriver housing, and the drive housing is in particular at its end axially opposite the support arrangement, preferably on the front side, via a bearing, in particular a rolling bearing , preferably a deep groove ball bearing, rotatably mounted in the screwdriver housing. In particular, the entire drive train is rotatably mounted in the screwdriver housing via the rotatably mounted drive housing. This rotatable mounting of the drive housing contributes to stabilizing the drive housing within the screwdriver housing. At the same time, the reaction torque exerted on the drive housing is only supported at the axially opposite support point between the drive housing and the screwdriver housing via the support arrangement. For example, the support arrangement is between the axially front end of the drive housing, preferably the axial front face of the drive housing, and the screwdriver housing. In this case, the reaction torque is supported and recorded relatively close to the output shaft, which contributes to the output torque being recorded as precisely as possible.

The support arrangement can be connected to the screwdriver housing via an intermediate element. Preferably, the intermediate element is detachably connected to the support arrangement and/or the screwdriver housing, in particular screwed. By using a suitable intermediate element, the support arrangement can be connected to screwdriver housings of different geometries. Screw connections are known to have the advantage that they can be detached.

A further embodiment of the invention is characterized in that a coupling device is provided, via which a bit holder is connected to the output shaft, in particular the axially front end of the output shaft, in a rotationally fixed but axially displaceable manner relative to it. Here, the coupling device is connected to the output shaft, preferably releasably connected, in particular screwed, and the axially rear end of the bit holder is in rotationally fixed but axially displaceable engagement with the coupling device. The bit holder can be guided in an axially displaceable manner at the axially front end of the screwdriver housing via a bearing arrangement which includes a bearing, in particular a plain bearing. The coupling device can be surrounded by a coupling device housing which is arranged in the axially front end section of the screwdriver housing and is detachably connected to it, preferably screwed. In principle, the coupling device housing can also be designed in one piece with the screwdriver housing. Elastic restoring means, such as a helical compression spring, disc spring and/or rubber spring, are expediently provided, which are located between the coupling device and Support the bit holder and push the bit holder into an axially forward starting position. The elastic restoring means preferably encompass the bit holder in order to be supported on the inside by it. Because the bit holder is axially displaceable relative to the output shaft against the restoring force of the elastic restoring means, the contact pressure exerted on the bit holder can be detected, for example with a suitable measuring device, and as soon as the detected contact pressure reaches or exceeds the value of a desired triggering force, the motor Switch on according to the torque wrench arrangement. If an intermediate element is provided, the support arrangement can be connected to the screwdriver housing via the coupling device housing as an intermediate element.

The drive housing is connected to the screwdriver housing at the support point via the support arrangement. The support assembly may include drive housing connecting means designed and/or configured to releasably connect the support assembly to the drive housing. The support arrangement can also be firmly connected to the drive housing. For example, the support arrangement can be welded, pressed and/or glued to the drive housing. It is also possible for the support arrangement to be formed in one piece with the drive housing. The support arrangement can also include screwdriver housing connecting means which are designed and/or set up to connect the support arrangement, in particular releasably, to the screwdriver housing or to an intermediate element provided between the screwdriver housing and the support arrangement. In principle, the support arrangement can also be designed in one piece with the intermediate element. The torque measuring device is advantageously designed and/or set up to measure the reaction torque axially between the screwdriver housing connecting means and the drive housing connecting means.

The support arrangement advantageously comprises an annular, in particular annular, fastening flange, which has through holes between its two end faces, as a drive housing connecting means, via which the fastening flange is connected to an end face of the drive housing. The annular fastening flange can be provided with material reinforcements projecting radially inwards, with a through hole preferably extending through each of these material reinforcements. Alternatively, the annular fastening flange can have a uniform thickness measured in the radial direction. The through holes are preferably arranged in particular evenly spaced apart from one another in the circumferential direction of the fastening flange. In the case of a uniform spacing of the through holes, the fastening flange is attached to the drive housing with a relatively uniform thickness in its circumferential direction. This can also contribute to the most precise detection of the output torque. The through holes can each be designed as stepped bores with a drive housing-side section of smaller diameter and an adjoining section of larger diameter. This has the advantage, for example, that the head of a fastener extending through the stepped bore can be sunk into the larger diameter section of the stepped bore. Preferably, the support arrangement comprises a central through opening through which in particular a part of the output shaft extends and/or into which the output shaft in particular protrudes.

According to a further advantageous embodiment, the support arrangement is designed as a torsionally elastic support arrangement and comprises a in particular the sleeve defining the central through opening of the support arrangement, on which the screwdriver housing connecting means are formed, and an outer ring having the drive housing connecting means, which is in particular formed by the fastening flange and which radially surrounds the sleeve. Here, the sleeve and the outer ring, in particular the fastening flange, are preferably connected to one another in a torsionally elastic manner via radial connecting webs, preferably connected to one another exclusively via the radial connecting webs and are otherwise spaced apart from one another by a gap, in particular an air gap. The gap can be at least partially filled with an elastic mass, thereby preventing contamination. Preferably, at least one connecting web comprises the torque measuring device or a part thereof, or at least one connecting web consists of the torque measuring device, or at least one connecting web is connected to the torque measuring device or a part thereof. This is particularly advantageous if the sleeve and the outer ring are connected to one another exclusively via the connecting webs, because in this case the reaction torque is supported exclusively via the connecting webs, which is why the reaction torque is recorded particularly precisely by means of the torque measuring device on the connecting webs can. There is expediently at least one, preferably exactly one, connecting web between two through holes adjacent in the circumferential direction of the fastening flange. It is also possible not to provide a connecting web between at least one pair of through holes adjacent in the circumferential direction of the fastening flange. For example, there can be two pairs of through holes adjacent in the circumferential direction of the fastening flange, between which no connecting web is provided. The two areas of the support arrangement, on which no connecting web is provided, are preferably radially opposite one another.

The sleeve is connected at an axial end region, in particular its axially rear end region, via the connecting webs to the outer ring, in particular the fastening flange, and at the opposite axial end region, in particular its axially front end region, is provided with an internal or external thread section as a screwdriver housing connecting means . Via the internal or external thread section, the torsionally elastic support arrangement can be in threaded engagement with a correspondingly designed internal or external thread section of the screwdriver housing or with an intermediate element provided between the torsionally elastic support arrangement and the screwdriver housing. Here, the corresponding internal or external thread section is provided in particular at the axially rear end of the intermediate section. Preferably, the sleeve is provided with an externally threaded section and the screwdriver housing or the intermediate element is provided with a correspondingly designed internally threaded section. Such a screw connection can be made and released quickly.

The side surfaces of the connecting webs pointing in the circumferential direction of the torsionally elastic support arrangement can be designed as planar surfaces. In addition, the connecting webs can each have an at least substantially uniform thickness in the circumferential direction of the torsionally elastic support arrangement. In general, it is advantageous if the connecting webs have a uniform or at least essentially uniform dimension. This makes it easier to calibrate the torque measuring device and/or the torque wrench arrangement. Preferably, the connecting webs are arranged evenly spaced apart from one another in the circumferential direction of the torsionally elastic support arrangement. This is particularly advantageous if the torque measuring device or Parts of it are integrated into the connecting webs or attached to them, so the reaction torque is measured on the connecting webs. In this case, the output torque can be recorded particularly precisely due to the measuring points evenly distributed along the circumference of the torsionally elastic connecting element.

According to a further advantageous embodiment, the torque measuring device comprises at least one strain gauge, which is arranged and / or connected in such a way that a torque can be measured, and which is preferably based on the principle of the Wheatstone bridge to one or more quarter, half and / or Full bridges are connected. Several bridges can be connected in series, parallel and/or mixed. Stretching and compressing deformations can be measured using strain gauges. Strain gauges change their electrical resistance even with small deformations. The strain gauge(s) is or are expediently designed and/or arranged and/or connected in such a way that they each change their electrical resistance in the event of a deformation caused by a reaction torque and this change in resistance can be measured and the acting torque can in turn be derived from this. Preferably, the at least one strain gauge is applied to a side surface of a connecting web pointing in the circumferential direction of the torsionally elastic support arrangement. In particular, at least one strain gauge is applied to the side surfaces of the connecting webs pointing in the circumferential direction of the torsionally elastic support arrangement.

A further embodiment of the invention is characterized in that the support arrangement has a drive housing-side support element, on which the drive housing connecting means are provided, and a screwdriver housing-side support element, on which the screwdriver housing connecting means are provided. Here, one of the two support elements can be provided with at least one recess and the other support element can be provided with at least one correspondingly designed projection projecting into the recess, a gap being formed between two opposite side surfaces of a recess and an associated projection pointing in the circumferential direction of the support arrangement is, and the arrangement is such that the reaction torque is supported in the circumferential direction of the support arrangement between the side surfaces. Preferably, a part of the torque measuring device, in particular at least one piezo element and/or piezoelectric sensor and/or piezoresistive sensor of the torque measuring device, is arranged in at least one gap. Here, the part of the torque measuring device can be arranged in such a way, preferably attached to at least one of the two side surfaces, that when the width of the gap is reduced when the two support elements are rotated relative to one another, pressure is exerted on the part of the torque measuring device arranged in the gap can be detected as an electrical signal. The electrical signal can be detected in particular by means of control electronics.

Advantageously, the drive housing-side support element is designed as an annular fastening flange and/or the screwdriver housing-side support element is designed as an annular plate. The at least one projection or the at least one recess can be arranged on the end face of the annular plate facing the drive housing-side support element. On the opposite end face of the annular plate there can be a sleeve-like extension, which is arranged in particular coaxially with a central bore in the annular plate. The bore and the extension of the annular plate preferably form part of a central through opening of the support arrangement, through which in particular a part of the output shaft extends and/or into which the output shaft projects. The sleeve-like extension can be provided with an internal or external thread section as a screwdriver housing connecting means, via which the screwdriver housing-side support element is in threaded engagement with a correspondingly designed internal or external thread section of the screwdriver housing or an intermediate element provided between the screwdriver housing-side support element and the screwdriver housing.

Advantageously, the torque measuring device comprises at least one sensor, such as a resistance sensor and/or an electromagnetic sensor and/or a Hall sensor and/or a magnetoresistive sensor and/or a galvanomagnetic sensor and/or an optoelectronic sensor and/or a piezo element and/or a piezoelectric sensor and/or a piezoresistive sensor. The torque measuring device can also include a sensor that is designed and/or set up to measure a twist angle and/or a position and/or a deformation and/or a twist and/or a rotation and/or a torsion and/or a shear force and/or to detect shearing of the particularly torsionally elastic support arrangement, in particular a region of the support arrangement, and/or of the drive housing. When later converting the measured values obtained from a sensor to the reaction torque, the material stiffness of the torsionally elastic support arrangement can in particular be taken into account.

A further embodiment of the invention is characterized in that the torque measuring device comprises at least two measuring device elements which are designed and/or arranged in such a way that during a rotational deflection of the particularly torsionally elastic support arrangement be moved relative to each other. Preferably, at least one measuring device element is a sensor or part of a sensor. The sensor can be, for example, one of the sensors listed previously. The measuring device elements are particularly preferably a magnetic field generating element and a magnetic field measuring element. A Hall sensor and/or a magnetoresistive element, for example, can be used as a magnetic field measuring element. The use of magnetic field generating and magnetic field measuring elements enables particularly precise detection of the output torque compared to other possible measuring device elements. In addition, magnetic field generating and magnetic field measuring elements can be installed relatively easily.

If the support arrangement comprises a sleeve and an outer ring, in particular a fastening flange, which are connected to one another via connecting webs, a measuring device element of the torque measuring device is preferably arranged on a radially outer surface of the sleeve, in particular mounted on a pedestal. Preferably, the measuring device element is arranged on a radially outer surface of the axial end region of the sleeve, on which the sleeve is connected to the outer ring via the connecting webs, in particular mounted on a pedestal. A further measuring device element of the torque measuring device is preferably arranged on a radially inner surface of the outer ring, preferably of the annular fastening flange, in particular mounted on a pedestal. The arrangement of one measuring device element on the sleeve and the other measuring device element on the outer ring can of course also be reversed. Advantageously, the two measuring device elements of the torque measuring device lie opposite each other, but in particular do not touch each other. The torque measuring device can be designed and/or set up to in order to detect a displacement of its two measuring device elements in the circumferential direction of the torsionally elastic support arrangement relative to one another when the sleeve and the outer ring, in particular the fastening flange, are rotated against one another. An arrangement of two opposing measuring device elements of the torque measuring device can be provided instead of a connecting web. In addition, the arrangement can be positioned in the circumferential direction of the torsionally elastic support arrangement, in particular between two adjacent through holes in the fastening flange. Preferably, no connecting web is provided in a region of the torsionally elastic support arrangement that is directly radially opposite the arrangement.

According to a further embodiment, the drive train has a transmission which connects to the axially front end of the motor and is arranged in the drive housing. Here, the drive housing can be designed in two parts, with the motor being arranged in a first, in particular axially rear, part of the drive housing and the gearbox being arranged in a second, in particular axially front, part of the drive housing. Furthermore, the drive housing can be separated from the screwdriver housing in the radial direction by a gap, in particular an air gap. This supports the rotatable storage of the drive housing in the screwdriver housing.

A further embodiment of the invention is characterized in that control electronics are provided which are coupled to the torque measuring device and the motor in order to switch off the motor depending on output signals from the torque measuring device. The motor of the torque wrench arrangement can therefore be switched off automatically as soon as a predetermined target torque is reached is exceeded, whereby damage to a screw connection produced by means of the torque screwdriver arrangement is avoided. The control electronics can be internal control electronics arranged on the screwdriver housing, in particular at least partially, possibly completely within the screwdriver housing, external control electronics arranged remotely from the screwdriver housing and/or a higher-level controller. In addition, the control electronics can have a memory, in particular a RAM memory, for storing several predefined target torques and / or a user interface or a setting and / or input means, in particular a touch-sensitive screen, a jog wheel and / or a membrane keyboard, for setting a particular target torque stored in the memory. In addition, it can be provided that the torque of the motor can be adjusted and/or stored via a potentiometer, in particular directly on an electric screwdriver of the torque screwdriver arrangement.

Figur 1

eine schematische Teilschnittansicht einer Drehmomentschrauberanordnung gemäß einer ersten Ausführungsform der vorliegenden Erfindung;

Figur 2

eine vergrößerte Ansicht des in Figur 1 mit dem Buchstaben "A" gekennzeichneten Bereichs der Drehmomentschrauberanordnung;

Figur 3

eine vergrößerte Ansicht des in Figur 1 mit dem Buchstaben "A" gekennzeichneten Bereichs der Drehmomentschrauberanordnung mit zusätzlich eingezeichnetem Drehmomentübertragungsweg;

Figur 4

eine vergrößerte Ansicht des in Figur 1 mit dem Buchstaben "B" gekennzeichneten Bereichs der Drehmomentschrauberanordnung;

Figur 5

eine perspektivische Ansicht eines axial vorderen Bereichs der Drehmomentschrauberanordnung gemäß der ersten Ausführungsform;

Figur 6

eine perspektivische Ansicht einer drehelastischen Abstützanordnung der Drehmomentschrauberanordnung gemäß der ersten Ausführungsform;

Figur 7

eine Vorderansicht der drehelastischen Abstützanordnung aus Figur 6;

Figur 8

eine vergrößerte Ansicht des in Figur 7 mit dem Buchstaben "C" gekennzeichneten Bereichs der drehelastischen Abstützanordnung;

Figur 9

eine weitere Vorderansicht der drehelastischen Abstützanordnung aus Figur 6;

Figur 10

eine Vorderansicht einer drehelastischen Abstützanordnung einer Drehmomentschrauberanordnung gemäß einer zweiten Ausführungsform der vorliegenden Erfindung;

Figur 11

eine perspektivische Ansicht einer Abstützanordnung einer Drehmomentschrauberanordnung gemäß einer dritten Ausführungsform der vorliegenden Erfindung;

Figur 12

eine Vorderansicht eines antriebsgehäuseseitigen Abstützelements der Abstützanordnung aus Figur 11;

Figur 13

eine schematische Teilschnittansicht der Drehmomentschrauberanordnung gemäß den ersten, zweiten und dritten Ausführungsformen mit angedeuteter Position einer Abstützstelle zwischen Antriebsgehäuse und Schraubendrehergehäuse;

Figur 14

eine vergrößerte Ansicht des axial vorderen Bereichs der Drehmomentschrauberanordnung von Figur 13;

Figur 15

eine schematische Teilschnittansicht einer Drehmomentschrauberanordnung gemäß einer vierten Ausführungsform der vorliegenden Erfindung; und

Figur 16

eine Veranschaulichung des Reaktions-Drehmoments in Bezug auf das Abtriebs-Drehmoment.

Further features and advantages of the present invention will become apparent from the following description of four embodiments of a torque wrench assembly according to the present invention with reference to the accompanying drawing. In it is:

Figure 1

a schematic partial sectional view of a torque wrench assembly according to a first embodiment of the present invention;

Figure 2

an enlarged view of the in Figure 1 area of the torque wrench assembly marked with the letter “A”;

Figure 3

an enlarged view of the in Figure 1 Area of the torque wrench arrangement marked with the letter “A” with an additional torque transmission path marked;

Figure 4

an enlarged view of the in Figure 1 area of the torque wrench assembly marked with the letter “B”;

Figure 5

a perspective view of an axially front portion of the torque wrench assembly according to the first embodiment;

Figure 6

a perspective view of a torsionally elastic support arrangement of the torque wrench arrangement according to the first embodiment;

Figure 7

a front view of the torsionally elastic support arrangement Figure 6 ;

Figure 8

an enlarged view of the in Figure 7 area of the torsionally elastic support arrangement marked with the letter “C”;

Figure 9

another front view of the torsionally elastic support arrangement Figure 6 ;

Figure 10

a front view of a torsionally elastic support assembly of a torque wrench assembly according to a second embodiment of the present invention;

Figure 11

a perspective view of a support assembly of a torque wrench assembly according to a third embodiment of the present invention;

Figure 12

a front view of a drive housing-side support element of the support arrangement Figure 11 ;

Figure 13

a schematic partial sectional view of the torque wrench arrangement according to the first, second and third embodiments with an indicated position of a support point between the drive housing and the screwdriver housing;

Figure 14

an enlarged view of the axially front region of the torque wrench assembly from Figure 13 ;

Figure 15

a schematic partial sectional view of a torque wrench assembly according to a fourth embodiment of the present invention; and

Figure 16

an illustration of reaction torque in relation to output torque.

The Figures 1 to 9 show a torque wrench assembly 1 according to a first embodiment of the present invention. The torque screwdriver arrangement 1 has an electric screwdriver 2 and external control electronics 3a connected to it. The electric screwdriver 2 includes a screwdriver housing 4, which consists of an axially front housing section 4a, a middle housing section 4b and an axially rear housing section 4c.

Furthermore, the electric screwdriver 2 has a drive train 5 arranged in the middle and axially front housing sections 4a, 4b of the screwdriver housing 4. This has a two-part drive housing 7 separated in the radial direction by a gap 6, here an air gap, from the screwdriver housing 4, a motor 8 in the form of an electric motor arranged in an axially rear part 7a of the drive housing 7, a motor 8 in the form of an electric motor in an axially front part 7b of the screwdriver housing 4 Drive housing 7 arranged and connected to the motor 8 gear 9, and an output shaft 10 of the gear 9. The output shaft 10 protrudes from the drive housing 7 on its axially front end. The axially front end of the output shaft 10 is connected in a rotationally fixed manner to a bit holder 11 with a bit holder 12 for fixing a screw bit, not shown. Furthermore, the electric screwdriver 2 comprises a torsionally elastic support arrangement 13, which is provided at exactly one support point 14 and via which the reaction torque exerted on the drive housing 7 during operation of the torque screwdriver arrangement 1 is supported on the screwdriver housing 4. The drive housing 7 is connected to the screwdriver housing 4 at the support point 14 via the torsionally elastic support arrangement 13 and is otherwise rotatable in the screwdriver housing 4. More precisely, the torsionally elastic support arrangement 13 is arranged between the axially front end face of the drive housing 7 and the screwdriver housing 4 and the drive housing 7 is rotatably mounted in the screwdriver housing 4 on its axially rear end face, in this case via a roller bearing, here a deep groove ball bearing 15.

In addition, the electric screwdriver 2 is equipped with a torque measuring device 16 with eight strain gauges 16a. The torque measuring device 16 is designed and/or set up in order to detect the output torque of the output shaft 10 in the form of the supported reaction torque on the torsionally elastic support arrangement 13.

Furthermore, the electric screwdriver 2 includes a coupling device 17, via which the bit holder 11 is connected to the axially front end of the output shaft 10 in a rotationally fixed manner but is axially displaceable relative to it. For this purpose, the axially rear end of the bit holder 11 is in rotationally fixed but axially displaceable engagement with the coupling device 17. In the present case, the bit holder 11 is guided in an axially displaceable manner at the axially front end of the screwdriver housing 4 via a bearing arrangement 18 comprising a plain bearing. The coupling device 17 is detachably connected to the output shaft 10. In addition, the coupling device 17 is surrounded by a coupling device housing 19, which is arranged in the axially front housing section 4a of the screwdriver housing 4 and is releasably connected to it, more precisely screwed at a screw connection point 20. The bit holder 11 is pressed into an axially forward starting position by elastic restoring means 21 in the form of a helical compression spring. Specifically, the helical compression spring is supported axially between a front end face of the coupling device 17 and a rear end face of the bit holder 11, being placed on the axially rear end section of the bit holder 11 so that it surrounds it and is supported on the inside by it.

The torsionally elastic support arrangement 13 has an outer ring formed by an annular fastening flange 22. The fastening flange 22 is provided between its two end faces with four through holes 23 as drive housing connecting means, via which the fastening flange 22 is detachably connected to the axially front end face of the drive housing 7. The through holes 23 extend each through an area of the fastening flange 22, on which the latter is reinforced by means of material reinforcements projecting radially inwards. Specifically, the fastening flange 22 is screwed to the drive housing 7 by means of fastening screws 24, which extend through the through holes 23. The through holes 23 are arranged evenly spaced apart from one another in the circumferential direction of the fastening flange 22 and are designed as stepped holes with a drive housing-side section 23a of smaller diameter and an adjoining section 23b of larger diameter. As can be seen in particular in Figure 5, the screw heads 25 of the fastening screws 24 are each sunk in one of the larger diameter sections 23a.

Furthermore, the torsionally elastic support arrangement 13 comprises a sleeve 26, which defines a central through opening 27 of the torsionally elastic support arrangement 13, through which the output shaft 10 extends. The sleeve 26 is surrounded radially by the fastening flange 22 and is connected at its axially rear end region to the fastening flange 22 via four radial connecting webs 28. In principle, however, the sleeve 26 can be connected to the fastening flange 22 via any number of connecting webs 28. Here, the sleeve 26 and the fastening flange 22 are connected to one another exclusively via the connecting webs 28 and are otherwise spaced apart from one another by a gap 29, here an air gap. The gap 29 can be at least partially filled with an elastic mass. There is exactly one connecting web 28 in the middle between two through holes 23 adjacent in the circumferential direction of the fastening flange 22. An off-center arrangement of the connecting webs 28 is also possible. The connecting webs 28 are arranged evenly spaced apart from one another in the circumferential direction of the torsionally elastic support arrangement 13. In addition, the connecting webs 28 each have one in the circumferential direction of the torsionally elastic support arrangement 13 uniform thickness. In general, however, the thickness does not have to be uniform. The side surfaces 30 of the connecting webs 28 pointing in the circumferential direction of the torsionally elastic support arrangement 13 are designed as planar surfaces.

In addition, the sleeve 26 is provided at its axially front end region with an externally threaded section 31 as a screwdriver housing connecting means. Via the external thread section 31, the sleeve 26 is in threaded engagement with a correspondingly designed internal thread section 32 at the axially rear end of the coupling device housing 19. In this way, the torsionally elastic support arrangement 13 is connected to the screwdriver housing 4 via the coupling device housing 19 as an intermediate element.

In addition, the torque measuring device 16 is connected to the torsionally elastic support arrangement 13 and is designed and/or set up to detect the reaction torque axially between the screwdriver housing connecting means and the drive housing connecting means. For this purpose, a strain gauge 16a is applied to each side surface 30 of the connecting webs 28. The strain gauges 16a are connected in such a way that a reaction torque can be measured. In a further embodiment not shown here, a single strain gauge 16a can be provided, which is applied to a side surface 30 of one of the connecting webs 28.

Furthermore, the electric screwdriver 2 has internal control electronics 3b, which together with the external control electronics 3a are referred to as control electronics 3 of the screwdriver arrangement 1. The internal control electronics 3b is arranged within the axially rear housing section 4c of the screwdriver housing 4. The external one Control electronics 3a is located outside the electric screwdriver 2 and includes a memory 33 with predefined target torques stored therein and a user interface 34 in the form of a touch-sensitive screen. The internal control electronics 3b is connected to the external control electronics 3a at the axially rear end of the screwdriver housing 4 via a transmission line 35. The control electronics 3 is coupled to the torque measuring device 16 and the motor 8 in order to switch off the motor 8 depending on output signals from the torque measuring device 16. In a further embodiment not shown here, the torque wrench arrangement 1 only has internal control electronics 3b and no external control electronics 3a. In this case, the internal control electronics 3b can also take over the tasks of the external control electronics 3a. For this purpose, the internal control electronics 3b can include the memory 33 and/or the user interface 34.

Figure 10 shows a torsionally elastic support arrangement 13 of a torque wrench arrangement 1 according to a second embodiment of the present invention. The second embodiment is essentially identical to the first embodiment, which is why only the differences between the second embodiment and the first embodiment will be discussed below.

The second embodiment differs from the first embodiment only in a slightly modified design of the torsionally elastic support arrangement 13. This is because the sleeve 26 of the torsionally elastic support arrangement 13 is connected at its axially rear end region to the fastening flange 22 of the torsionally elastic support arrangement 13 only via two instead of four radial connecting webs 28 tied together. Here, the two connecting webs 28 lie radially opposite one another. Between two pairs of in No connecting webs 28 are therefore provided in the circumferential direction of the fastening flange 22 adjacent through holes 23. These areas without connecting webs 28 are also radially opposite one another. In addition, the torque measuring device 16 does not include any strain gauges 16a, but instead two measuring device elements, which are a magnetic field generating element, here a magnet 16b, and a magnetic field measuring element, here a Hall sensor 16c. The magnet 16b is mounted on a radially outer surface 36 of the sleeve 26 on a pedestal 37 and the Hall sensor 16c is mounted on a radially inner surface 38 of the annular fastening flange 22 on a further pedestal 39. In a further embodiment not shown here, the magnet 16b can be arranged mounted on the surface 38 and the Hall sensor 16c on the surface 36 on a respective pedestal 37, 39. The magnet 16b and the Hall sensor 16c are directly opposite each other, but do not touch each other. The arrangement of the two platforms 37, 39, the magnet 16c and the Hall sensor 16c is located at a position at which a further connecting web 28 is provided in the first embodiment.

The Figures 11 and 12 show a support arrangement 13 of a torque wrench arrangement 1 according to a third embodiment of the present invention. The third embodiment is essentially identical to the first and second embodiments, which is why only the differences between the third embodiment and the first and second embodiments will be discussed below.

The third embodiment differs from the first and second embodiments only in a modified design of the support arrangement 13. In the third embodiment, this consists of two separate elements, which is why the drive housing 7 over the support arrangement 13 is not connected to the screwdriver housing 4. More precisely, the support arrangement 13 has a drive housing-side support element 40 and a screwdriver housing-side support element 41, which rest against one another with their mutually facing end faces 43, 46. The drive housing-side support element 40 is designed as an annular fastening flange 22 with four through holes 23 as drive housing connecting means and a central hole 42. In addition, the drive housing-side support element 40 is provided with a recess 44 on its end face 43 facing the screwdriver housing-side support element 41. The screwdriver housing-side support element 41 is designed as an annular plate 45, on whose end face 46 facing the drive housing-side support element 40 there is a projection 47 which is designed to correspond to the recess 44 and projects into it. On the opposite end face 48 of the annular plate 45 there is a sleeve-like extension 49 which is arranged coaxially with a central bore 50 in the annular plate 45. Here, the central bore 50 of the annular plate 45, the extension 49 and the central bore 42 of the fastening flange 22 form the central through opening 27 of the support arrangement 13. The sleeve-like extension 49 is provided with an external thread section 51 as a screwdriver housing connecting means, via which the screwdriver housing-side support element 41 is in threaded engagement with the correspondingly designed internal thread section 32 at the axially rear end of the coupling device housing 19.

In the third embodiment, a gap 53 is formed between two opposite side surfaces 52 of the recess 44 and the projection 47, which point in the circumferential direction of the support arrangement 13. The arrangement is such that the support of the reaction torque in the circumferential direction of the support arrangement 13 between the side surfaces 52 takes place. In the present case there are a total of two columns 53, in each of which a piezo element 16d of the torque measuring device 16 is arranged. Piezo elements 16d are therefore provided on the support arrangement 13 according to the third embodiment instead of strain gauges 16a or instead of a magnet 16b and a Hall sensor 16c. More precisely, the two piezo elements 16d are each attached to a side surface 52 of a gap 53 belonging to the support element 40 on the drive housing side.

The Figures 13 and 14 show schematic partial sectional views of the torque wrench assembly 1 according to the first, second and third embodiments. These are only intended to clarify the location of the support point 14. In the case of the first, second and third embodiments, the support point 14 is located at the axially front end of the drive housing 7. Specifically, the support arrangement 13 is arranged between the axially front end face of the drive housing 7 and the screwdriver housing 4.

Figure 15 shows a schematic partial sectional view of a torque wrench assembly 1 according to a fourth embodiment of the present invention. The fourth embodiment differs from the first, second and third embodiments in that the support point 14 is located at the axially rear end of the drive housing 7. The support arrangement 13, via which the reaction torque exerted on the drive housing 7 is supported at the support point 14 on the screwdriver housing 4, is, for example, one of the support arrangements 13 described in connection with the first three embodiments According to the invention, the drive housing 7 is rotatably mounted in the screwdriver housing 4 at its axially front end.

The torque wrench arrangement 1 according to the invention according to the four embodiments described above can be operated according to the method explained below.

On the external control electronics 3a, a user can first set a desired target torque via the user interface 34 by entering the desired target torque or selecting from several predefined selection options stored in the memory 33. The screwdriver 2 is then pressed by the user against a screw to be turned using a screw bit fixed in the bit holder 12 of the bit holder 11 and the screwdriver 2 is activated either automatically when a desired contact pressure is reached or manually by the user, i.e. the motor 8 is switched on . For the sake of clarity, neither the screw bit nor the screw are shown in the figures.

When turning the screw using the screwdriver 2, the output torque of the output shaft 10 causes a reaction torque to be exerted on the drive housing 7, which is supported at the support point between the drive housing 7 and the screwdriver housing 4 via the support arrangement 13. By means of the torque measuring device 16, the output torque of the output shaft 10 is recorded in the form of the supported reaction torque on the support arrangement 13. For example, in the case of the first embodiment of the invention, i.e. in the case of using strain gauges 16a, the torque is detected by measuring a deformation of the torsionally elastic support arrangement 13, in particular the connecting webs 28 or the fastening flange 22. For example in the case of the second embodiment of the invention, i.e in the case of using a magnet 16b and one Hall sensor 16c, the torque is detected by measuring a displacement and/or rotation of the magnet 16b and the Hall sensor 16c in the circumferential direction of the torsionally elastic support arrangement 13 relative to one another during a rotational deflection of the torsionally elastic support arrangement 13, i.e. a rotation of the sleeve 26 and the fastening flange 22 against one another In the case of the third embodiment of the invention, i.e. in the case of the use of piezo elements 16d, the torque is detected by applying pressure to the support elements 40, 41 arranged in the gap 53 when the width of a gap 53 is reduced and the two support elements 40, 41 are rotated relative to one another Pizeoelement 16d is exerted, which can be detected as an electrical signal. In this way, the output torque can be recorded much more precisely via the reaction torque compared to previously known torque wrench arrangements. If necessary, the measurement can be compared with a recorded motor current of the motor 8.

The detected reaction torque is then compared with the preset desired target torque by means of the control electronics 3. As soon as the target torque is reached or exceeded, the control electronics 3 causes the motor 8 to be switched off automatically. In this way, damage to a screw connection produced by means of the torque wrench arrangement 1 can be avoided.

If necessary, the torque wrench arrangement 1 can be calibrated, in particular via the control electronics 3. A certified measuring method is used, which is compared with the measured values recorded from the screwdriver 2. Depending on the extent of the deviation in the measured values, the measured values recorded by the screwdriver 2 are then adjusted.

Figure 16 shows the relationship between the output torque M _from the output shaft 10 and the reaction torque M detected by means of the torque measuring device 16, where the following applies: M = - M _from

Reference symbol list

1

Torque wrench assembly

2

screwdriver

3

Control electronics

3a

external control electronics

3b

internal control electronics

4

Screwdriver case

4a

axial front housing section

4b

middle section of the housing

4c

axially rear housing section

5

Drivetrain

6

gap

7

Drive housing

7a

axially rear part of the drive housing

7b

axially front part of the drive housing

8th

engine

9

transmission

10

output shaft

11

Bit holder

12

Bit recording

13

Support arrangement

14

Support point

15

Roller bearing

16

Torque measuring device

16a

Strain gauges

16b

magnet

16c

Hall sensor

16d

Piezo element

17

Coupling device

18

Storage arrangement

19

Clutch device housing

20

screw connection point

21

elastic restoring means

22

mounting flange

23

Through hole

23a

Smaller diameter section

23b

Larger diameter section

24

Fastening screw

25

screw head

26

sleeve

27

central through opening of the support arrangement

28

connecting bridge

29

gap

30

side surface

31

Male thread section

32

Internal thread section

33

Storage

34

User interface

35

transmission line

36

Area

37

Pedestal

38

Area

39

Pedestal

40

Drive housing side support element

41

screwdriver housing side support element

42

central hole in the mounting flange

43

front side

44

recess

45

annular plate

46

front side

47

head Start

48

front side

49

sleeve-like extension

50

central hole in the annular plate

51

Male thread section

52

side surface

53

gap

Claims (16)

1. Torque screwdriver arrangement (1) with a screwdriver housing (4), a drive train (5) arranged in the screwdriver housing (4), which has a drive housing (7), a motor (8), in particular an electric motor, arranged in the drive housing (7), and an output shaft (10), which projects out of the drive housing (7) at its axially front end face and whose axially front end comprises a bit holder (11) for fixing a screw bit or can be connected in a rotationally fixed manner to such a bit holder, and a torque measuring device (16), wherein a support arrangement (13) is provided at precisely one support point (14), via which the reaction torque exerted on the drive housing (7) during operation of the torque screwdriver arrangement (1) is supported on the screwdriver housing (4), and the drive housing (7) is otherwise provided or mounted rotatably in the screwdriver housing (4), and wherein the torque measuring device (16), which is provided in particular on the support arrangement (13), is designed and/or set up to detect the output torque of the output shaft (10) in the form of the supported reaction torque at the support arrangement (13), characterized in that the drive housing (7) is connected to the screwdriver housing (4) at the support point (14) via the support arrangement (13),

   in that the support arrangement (13) has drive housing connecting means which are designed and/or set up to connect the support arrangement (13) releasably to the drive housing (7), and comprises screwdriver housing connecting means which are designed and/or set up to connect the support arrangement (13) to the screwdriver housing (4) or to an intermediate element provided between the screwdriver housing (4) and the support arrangement (13),

   in that the support arrangement (13) is designed as a torsionally elastic support arrangement (13) and comprises a sleeve (26) on which the screwdriver housing connecting means are formed, and an outer ring which has the drive housing connecting means and radially surrounds the sleeve (26), the sleeve (26) and the outer ring preferably being torsionally elastically connected to one another via radial connecting webs (28), and

   in that the sleeve (26) is connected to the outer ring at one axial end region, in particular its axially rear end region, via the connecting webs (28) and is provided at the opposite axial end region, in particular its axially front end region, with an internal or external threaded section (31) as screwdriver housing connecting means, via which the torsionally elastic support arrangement (13) is in threaded engagement with an inner or outer threaded portion (32), designed to correspond thereto, of the screwdriver housing (4) or of an intermediate element provided between the torsionally elastic support arrangement (13) and the screwdriver housing (4), the corresponding inner or outer threaded portion (32) being provided in particular at the axially rear end of the intermediate portion.
2. Torque screwdriver arrangement (1) according to claim 1, characterized in that the support arrangement (13) is arranged between an axial end of the drive housing (7), preferably an axial end face of the drive housing (7), and the screwdriver housing (4), and the drive housing (7) is rotatably mounted in the screwdriver housing (4), in particular at its end axially opposite the support arrangement (13), preferably at the end face, via a bearing, in particular a roller bearing (15), preferably a deep groove ball bearing.
3. Torque screwdriver arrangement (1) according to claim 1 or 2, characterized in that the support arrangement (13) is connected to the screwdriver housing (4) via an intermediate element, preferably the intermediate element being detachably connected, in particular screwed, to the support arrangement (13) and/or the screwdriver housing (4).
4. Torque screwdriver arrangement (1) according to one of the claims 1 to 3, characterized in that a coupling device (17) is provided, via which a bit holder (11) is connected to the output shaft (10), in particular the axially front end of the output shaft (10), but axially displaceable relative thereto, wherein the coupling device (17) is connected, preferably detachably connected, in particular screwed, to the output shaft (10) and the axially rear end of the bit holder (11) is in rotationally fixed but axially displaceable engagement with the coupling device (17), wherein in particular elastic restoring means (21), such as a helical compression spring, a disk spring and/or a rubber spring, are provided, which are supported between the coupling device (17) and the bit holder (11) and press the bit holder (11) into an axially forward starting position, wherein the elastic restoring means (21) preferably engage around the bit holder (11) in order to be supported by the latter on the inside.
5. Torque screwdriver arrangement (1) according to claim 4, characterized in that the coupling device (17) is surrounded by a coupling device housing (19) which is arranged in the axially front end section of the screwdriver housing (4) and is detachably connected, in particular screwed, thereto, the supporting arrangement (13) preferably being connected to the screwdriver housing (4) via the coupling device housing (19) as an intermediate element.
6. Torque screwdriver arrangement (1) according to any one of the preceding claims, characterized in that the torque measuring device (16) is designed and/or arranged to detect the reaction torque axially between the screwdriver housing connecting means and the drive housing connecting means, and/or

   in that at least one connecting web (28) comprises the torque measuring device (16) or a part thereof or consists of the torque measuring device (16) or is connected to the torque measuring device (16) or a part thereof and/or

   in that the sleeve (26) and the outer ring are connected to one another exclusively via the radial connecting webs (28) and are otherwise spaced apart from one another by a gap (29), the gap (29) being in particular at least partially filled with an elastic mass.
7. Torque screwdriver arrangement (1) according to one of the previous claims, characterized in that the support arrangement (13) comprises, as drive housing connection means, an annular, in particular circular, fastening flange (22), which in particular forms the outer ring of the drive housing connection means, which has, between its two end faces, through-holes (23), via which the fastening flange (22) is connected to an end face of the drive housing (7).
8. Torque screwdriver arrangement (1) according to one of the previous claims, characterized in that the support arrangement (13) comprises a drive housing-side support element (40), on which the drive housing connecting means are provided, and a screwdriver housing-side support element (41), on which the screwdriver housing connecting means are provided, and one of the two support elements (40, 41) is provided with at least one recess (44) and the other supporting element (40, 41) is provided with at least one projection (47) corresponding thereto and projecting into the recess (44), a gap (53) being formed in each case between two opposing side faces (52), pointing in the circumferential direction of the supporting arrangement (13), of a recess (44) and of an associated projection (47), and the arrangement is made in such a way that the reaction torque is supported in the circumferential direction of the support arrangement (13) between the side faces (52), wherein in particular in at least one gap (53) a part of the torque measuring device (16), in particular at least one piezoelectric element (16d) and/or piezoelectric sensor and/or piezoresistive sensor of the torque measuring device (16), is arranged, preferably fastened, to at least one of the two side surfaces (52) in such a way that, in the event of a reduction in the width of the gap (53), when the two supporting elements (40, 41) are rotated relative to one another, a pressure is exerted on the part of the torque measuring device (16) arranged in the gap (53), which pressure can be detected as an electrical signal.
9. Torque screwdriver arrangement (1) according to claim 8, characterized in that the drive housing-side support element (40) is designed as an annular fastening flange (22) and/or the screwdriver housing-side support element (41) is designed as an annular plate (45), on whose end face (46) facing the drive housing-side support element (40) the at least one projection (47) or the at least one depression is arranged and on whose opposite end face (48) a sleeve-like extension (49) is located, which is arranged coaxially with a central bore (50) of the annular plate (45),
   wherein in particular the sleeve-like extension (49) is provided with an internally or externally threaded portion (51) as screwdriver housing connecting means, via which the screwdriver housing-side support element (41) is in threaded engagement with a correspondingly formed internal or external threaded portion (32) of the screwdriver housing (4) or of an intermediate element provided between the screwdriver housing-side support element (41) and the screwdriver housing (4).
10. Torque screwdriver arrangement (1) according to any one of the preceding claims, characterized in that the support arrangement (13) comprises a central through opening (27) defined by the sleeve (26) through which in particular a part of the output shaft (10) extends and/or into which in particular the output shaft (10) projects, and the sleeve (26) and the outer ring are connected to one another exclusively via the radial connecting webs (28) and are otherwise spaced apart from one another by a gap (29), the gap (29) being in particular at least partially filled with an elastic mass.
11. Torque screwdriver arrangement (1) according to claims 9 and 10, characterized in that the bore (50) and the extension (49) form part of the central through-opening (27) of the support assembly (13).
12. Torque screwdriver arrangement (1) according to one of the preceding claims, characterized in that the torque measuring device (16) comprises at least one strain gauge (16a) which is arranged and/or connected in such a way that a torque can be measured with it and which is preferably connected according to the principle of the Wheatstone bridge to form one or more quarter, half and/or full bridges, where, in particular, a plurality of bridges are connected to one another in series, in parallel and/or mixed, wherein preferably the at least one strain gauge (16a) is applied to a side face (30) of a connecting web (28) facing in the circumferential direction of the torsionally elastic support arrangement (13), wherein in particular at least one strain gauge (16a) is applied in each case to the side faces (30) of the connecting webs (28) facing in the circumferential direction of the torsionally elastic support arrangement (13).
13. Torque screwdriver arrangement (1) according to one of the preceding claims, characterized in that the side surfaces (30) of the connecting webs (28) facing in the circumferential direction of the torsionally elastic support arrangement (13) are designed as planar surfaces and/or the connecting webs (28) in the circumferential direction of the torsionally elastic support arrangement (13) each have an at least substantially uniform thickness and/or the connecting webs (28) are arranged at a uniform distance from one another in the circumferential direction of the torsionally elastic support arrangement (13).
14. Torque screwdriver arrangement (1) according to one of the preceding claims, characterized in that the torque measuring device (16) comprises at least one sensor, such as a resistance sensor and/or an electromagnetic sensor and/or a Hall sensor (16c) and/or a magnetoresistive sensor and/or a galvanomagnetic sensor and/or an optoelectronic sensor and/or a sensor, which is designed and/or set up to detect a torsion angle and/or a position and/or a deformation and/or a twist and/or a torsion and/or a shear force and/or a shear of the in particular torsionally elastic support arrangement (13), in particular of a region of the support arrangement (13), and/or of the drive housing (7), and/or

    in that the torque measuring device (16) comprises at least two measuring device elements which are designed and/or arranged in such a way that they are displaced relative to one another in the event of a rotational deflection of the, in particular, rotationally elastic support arrangement (13), and at least one of which is a sensor or part of a sensor, the measuring device elements being, in particular, a magnetic-field-generating element (16b) and a magnetic-field-measuring element, such as a Hall sensor (16c) and/or a magnetoresistive element, and/or

    in that a measuring device element of the torque measuring device (16) is arranged on a radially outer surface (36) of the sleeve (26), in particular mounted on a pedestal (37), and a further measuring device element of the torque measuring device (16) is arranged on a radially inner surface (38) of the outer ring, preferably of the annular mounting flange (22), in particular mounted on a pedestal (39), or vice versa, wherein the two measuring device elements of the torque measuring device (16) are opposite each other, in particular, however, do not touch each other, and the torque measuring device (16) is designed and/or arranged to detect a displacement of its two measuring device elements in the circumferential direction of the torsionally elastic support arrangement (13) relative to each other upon a twisting of the sleeve (26) and the outer ring, in particular, of the fastening flange (22), and wherein preferably,

    the arrangement of the two opposing measuring device elements of the torque measuring device (16) is provided instead of a connecting web (28) and the arrangement is positioned in the circumferential direction of the torsionally elastic support arrangement (13), in particular between two adjacent through holes (23) of the fastening flange (22).
15. Torque screwdriver arrangement (1) according to one of the previous claims, characterized in that control electronics (3) are provided which are coupled to the torque measuring device (16) and the motor (8) in order to switch off the motor (8) as a function of output signals of the torque measuring device (16), wherein
    the control electronics (3) are in particular internal control electronics (3b) arranged on the screwdriver housing (4), in particular at least partially arranged inside the screwdriver housing (4), external control electronics (3a) arranged remotely from the screwdriver housing (4) and/or a higher-level controller.
16. Torque screwdriver arrangement (1) according to one of the preceding claims, characterized in that the drive housing (7) is separated from the screwdriver housing (4) in the radial direction by a gap (6), and/or
    in that the drive train (5) has a gear unit (9) which adjoins the axially front end of the motor (8) and is arranged in the drive housing (7).

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