PRESSING DEVICE

Description

TECHNICAL AREA

[0001] The present invention relates to a pressing device according to the preamble of claim 1, as known from WO02 / 102555A1. STATE OF THE ART

[0002] Press fittings are frequently used to connect drinking water pipes, and these are crimped using a crimping tool. Such crimping tools comprise a crimping device and a crimping tool, such as a crimping jaw or crimping loop, which is interchangeably attached to the crimping device. The crimping device applies crimping force to the crimping jaws, which then crimp the fitting. During the crimping process, a piston in the crimping device extends with high force and acts on the crimping jaws.

[0003] DE 100 510 10 discloses a pressing tool which has a force sensor in the area of ​​the levers of a pressing head. DE 10 2015 107 302 discloses a pressing tool with a sensor in the area of ​​the pressing contour. Finally, EP 3 620 264 discloses a method for determining pressing force by measuring various quantities, such as current consumption or power consumption. PRESENTATION OF THE INVENTION

[0004] Based on this prior art, the invention is based on the objective of providing a pressing device that overcomes the disadvantages of the prior art. In particular, it is an objective of the present invention to provide a pressing device that allows for a technically simple sensor arrangement for measuring a force acting during a pressing process. This is especially important with regard to the requirement of accurate measurement.

[0005] A press device according to claim 1 solves these and other problems. Accordingly, a press device comprises a drive element with an output section, a spindle drive driven by the output section, the spindle having a spindle defining a central axis, and a spindle nut, wherein either the spindle or the spindle nut has a support area by which the spindle or the spindle nut is supported at a bearing point, a press piston driven by the spindle drive, and a tool holder for receiving a press tool. The press device further comprises a sensor unit for measuring an axial force acting in the direction of the central axis. The sensor unit comprises a force sensor and a sensor holder.The sensor mount is operatively connected to the spindle and the bearing point or to the spindle nut and the bearing point in such a way that the sensor mount is subjected to the aforementioned axial force during a pressing process and that the axial force can be detected with the force sensor.

[0006] The described arrangement of the sensor mount offers the advantage that the sensor mount is subjected to the axial force via the functional connection, thus allowing the sensor to detect the effective axial force. This makes the measurement very simple.

[0007] The measured axial force can be processed in various ways. For example, the pressing process can be controlled and / or recorded.

[0008] Furthermore, the sensor detects the actual force acting upon it, which means an accurate measurement of the axial force. In particular, the axial force does not need to be derived from other quantities.

[0009] Axial force is understood as the force that acts on the spindle or spindle nut during a pressing process. That is, it is the force that is transmitted from the spindle or spindle nut to the pressing tool.

[0010] The term "wirkverbunden" refers to a direct or indirect mechanical connection or support.

[0011] The piston acts on the pressing tool located in the tool holder. For this purpose, the piston may, for example, have pressing rollers. The pressing tool can be a pressing jaw or a pressing loop.

[0012] The support area is preferably designed as a shoulder, which extends radially away from the spindle or the spindle nut.

[0013] The drive unit can include a gearbox that reduces or amplifies the motion output by the drive element. Preferably, the drive unit includes an electric motor. However, the press device can also include a hydraulic or pneumatic motor as the drive element.

[0014] The spindle and the spindle nut are connected to each other via a thread.

[0015] In the embodiment where the spindle has a support area and is supported at the bearing point, the spindle nut is fixedly mounted so as to be displaceable in the direction of the central axis with respect to rotation about the central axis. When the spindle rotates, the spindle nut performs a longitudinal movement in the direction of the central axis. The spindle nut then acts on the press piston.

[0016] In the embodiment where the spindle nut has the support area and is supported at the bearing point, the spindle is fixedly mounted so as to be displaceable in the direction of the central axis with respect to rotation about the central axis. When the spindle nut rotates, the spindle performs a longitudinal movement in the direction of the central axis. The spindle then acts on the press piston.

[0017] Preferably, the sensor mount is arranged between the bearing point and the support area.

[0018] Furthermore, an axial bearing is arranged between the bearing point and the support area, such that the spindle or spindle nut is supported at the bearing point by the axial bearing with respect to forces acting in the direction of the central axis or with respect to the axial force. The sensor mount is in contact with the axial bearing in such a way that the axial force can be introduced into the sensor mount.

[0019] In one variant, the axial bearing is in contact with the support area, and the sensor mount is in contact with both the axial bearing and the bearing point. This means that, viewed along the central axis, the axial bearing is connected to the support area, and the sensor mount, which then rests on the bearing point, is connected to the axial bearing.

[0020] In another variant, the sensor mount is in contact with the support area, and the axial bearing is in contact with both the sensor mount and the bearing point. This means that, viewed along the central axis, the sensor mount is connected to the support area, and the axial bearing, which then rests on the bearing point, is connected to the sensor mount.

[0021] The expression "to be in contact" is to be understood as meaning that the elements in question are preferably in direct contact with each other.

[0022] The axial bearing is an axial ball bearing with a first bearing ring and a second bearing ring, as well as rolling elements arranged between the bearing rings.

[0023] Furthermore, the sensor receptacle is ring-shaped with a central opening, and the sensor receptacle has a first support surface and a second support surface.

[0024] In other words, the sensor receptacle is designed as a ring. Besides the central opening, the sensor receptacle has a cylindrical outer surface extending around the central axis, from which a first annular surface and a second annular surface, axially spaced from the first annular surface, extend towards the opening. The first and second annular surfaces may have recessed areas. In particular, the aforementioned support surfaces are such areas.

[0025] In one claimed variant, the first bearing ring is in contact with the support area, the second bearing ring is in contact with the first support surface, and the second support surface is in contact with the bearing point.

[0026] In another claimed variant, the first support surface is in contact with the support area, the second support surface is in contact with the first bearing ring, and the second bearing ring is in contact with the bearing point.

[0027] Preferably, the first support surface is spaced apart from the second support surface in a direction parallel to the central axis and in a direction transverse to the central axis.

[0028] Preferably, the first support surface is located on one of the two ring surfaces of the annular sensor receptacle and the second support surface is located on the other of the two ring surfaces of the annular sensor receptacle.

[0029] Preferably, the support surfaces are designed as ring surfaces, with the ring surfaces preferably extending concentrically around the central axis.

[0030] Preferably, the first support surface has an outer diameter that is smaller than the inner diameter of the second support surface.

[0031] Preferably, the support surfaces have no interruption. That is, the support surfaces extend completely around the central axis.

[0032] Preferably, the force sensor is arranged on a sensor surface at the sensor mount, wherein the sensor surface preferably lies in a plane extending perpendicular to the central axis.

[0033] Preferably, the sensor surface is arranged and designed such that the sensor surface experiences a bending load when subjected to the said axial force.

[0034] Preferably, the said sensor surface is offset radially and axially to the central axis relative to the first support surface, and the said sensor surface is offset radially and axially to the central axis relative to the second support surface.

[0035] In one variant, the sensor surface is located on the side of the first support surface and thus opposite the second support surface. In another variant, the sensor surface is located on the side of the second support surface and thus opposite the first support surface.

[0036] Preferably, the force sensor is a strain gauge and / or an inductive force sensor and / or a piezoelectric force sensor.

[0037] Preferably, the press device further comprises a housing that provides the bearing point directly or indirectly. Providing a direct bearing point means that the housing itself provides the bearing point. Providing an indirect bearing point means that the bearing point is provided by another element, such as a rolling bearing, which is supported by the housing.

[0038] Preferably, the sensor mount is axially and radially fixed in a bearing mount in the housing.

[0039] Preferably, the bearing point forms part of the bearing receptacle, and the sensor receptacle is in contact with an outer surface, with the second support surface above the bearing point, and with another surface with the bearing receptacle.

[0040] Further embodiments are specified in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Preferred embodiments of the invention are described below with reference to the drawings, which serve only for illustration and are not to be interpreted restrictively. The drawings show: Fig. 1 a partially cutaway perspective view of a pressing device according to the invention in a preferred first embodiment; Fig. 2 a further sectional view according to Figure 1 Fig. 3 a partially cutaway detail view of the press device according to the preceding figures; Fig. 4 a perspective detail view of a sensor mount from the press device according to Figure 1 Fig. 5 shows a cutaway detail view of the sensor image after Figure 4 ; and Fig. 6 a partially cutaway detail view of the press device according to a preferred second embodiment. DESCRIPTION OF PREFERRED EXECUTION FORMS

[0042] In the Figures 1 to 5A preferred first embodiment of a pressing device 1 is shown and described in the Figure 6 A preferred second embodiment is shown. Identical parts bear the same reference numerals, and the following description refers to both embodiments.

[0043] The press device 1 comprises a drive element 2, a spindle drive with a spindle 4 and a spindle nut 24, a press piston 7, and a tool holder 8 for receiving a press tool (not shown in the figures). The press device 1 further comprises a sensor unit 9, which is designed to measure an axial force, as explained below. In the embodiment shown, the press device also comprises a housing 20 on which the aforementioned elements are arranged.

[0044] The drive element 2 has an output section 3. In the first embodiment, the drive element is driven onto the spindle 4. In the second embodiment, the output section 3 acts on the spindle nut 24. The output section 3 and the spindle 4, or the output section 3 and the spindle nut 24, are connected to each other via a rotationally fixed connection. A rotary motion can be transmitted from the drive element 2 to the spindle 4 via the connection between the output section 3 and the spindle 4. A rotary motion can also be transmitted from the drive element 2 to the spindle nut 24 via the connection between the output section 3 and the spindle nut 24. Preferably, the drive element 2 is an electric motor. Other types of motors are also conceivable.

[0045] The spindle 4 defines a central axis M. Furthermore, in the first embodiment, the spindle 4 has a support area 5, via which the spindle 4 is supported at a bearing point 6. In the second embodiment, the spindle nut 24 has the support area 5. In the embodiments shown, the support area 5 is a flange that extends completely around the central axis M and radially away from the spindle 4 or the spindle nut 24.

[0046] In the first embodiment, the press piston 7 is connected to the spindle 4 via the spindle nut 24. When the spindle 4 is rotated, the spindle nut 24 and the press piston 7 are displaced in the direction of the central axis M. In the second embodiment, the press piston 7 is connected to the spindle nut 24 via the spindle 4. When the spindle nut 24 is rotated, the spindle 4 and the press piston 7 are displaced in the direction of the central axis M.

[0047] The press piston 7 is moved into the tool holder 8 by the movement of the spindle or spindle nut during a pressing operation and acts on the pressing tool through this movement. In the illustrated embodiment, press rollers 25 are arranged for this purpose.

[0048] The sensor unit 9 is arranged such that an axial force F acting in the direction of the central axis M, which acts on the spindle 4 or the spindle nut 24 during a pressing operation, can be measured. The sensor unit 9 has a force sensor 10 and a sensor mount 11. The sensor mount 11 is operatively connected to the spindle 4 and the bearing point 6 or to the spindle nut 24 and the bearing point 6 such that the sensor mount 11 is subjected to the aforementioned axial force F during a pressing operation and that the axial force F can be detected by the force sensor 10.

[0049] The sensor receptacle 11 is arranged between the bearing point 6 and the support area 5, whereby the axial force can be introduced from the support area 5 via the sensor receptacle 11 into the bearing point 6.

[0050] With reference to the Figures 2 and 3 for the first embodiment and on the Figure 6 For the second embodiment, the arrangement of the sensor mount 11 is now described.

[0051] In the illustrated embodiments, an axial bearing 12 is further arranged between the bearing point 6 and the support area 5. The spindle 4 or the spindle nut is supported at the bearing point 6 by the axial bearing 12 with respect to the acting axial force. The sensor receptacle 11 is in contact with the axial bearing 12 such that the axial force F can be introduced into the sensor receptacle 11. In the illustrated embodiment, the support area 5 rests directly on the axial bearing 12, and the axial bearing 12 rests directly on the sensor receptacle 11.

[0052] The axial bearing 12 is here an axial ball bearing with a first bearing ring 13 and a second bearing ring 14 as well as rolling elements 15 arranged between the bearing rings 13, 14.

[0053] In the illustrated embodiment, the sensor receptacle 11 is annular and has a central opening 16. The spindle 4 or the spindle nut 24 preferably extends through the central opening 16. The sensor receptacle further comprises a first support surface 17 and a second support surface 18. The support surfaces 17 and 18 are designed as annular surfaces, each extending in a plane transverse to the central axis M in a ring-shaped manner around the central axis M. The support surfaces 17 and 18 are offset from each other radially, i.e., transversely to the central axis M, as well as axially, i.e., in the direction of the central axis M. In the illustrated embodiment, the first support surface 17 has an outer diameter that is smaller than the inner diameter of the second support surface 18. In other words, the second support surface 18 is arranged radially outside the first support surface 17.

[0054] As mentioned, the first bearing ring 13 is in contact with the support area 5 of the spindle 4 or the spindle nut 24, and the second bearing ring 14 is in contact with the first support surface 17. The second support surface 18 is in contact with the bearing point 6.

[0055] The force sensor 10 is arranged on a sensor surface 19 on the sensor receptacle 11. The sensor surface 19 preferably lies in a plane extending perpendicular to the central axis M. In the illustrated embodiment, the sensor surface 19 is located on the side of the first support surface 17. The sensor surface 19 is axially and radially offset from the first support surface 17. The axial offset is such that a kind of cavity can be created in which the pressure sensor 10 can be arranged.

[0056] In the sectional views of the Figures 2 and 6The operating principle can be clearly seen. When an axial force F is applied from the support area 5 via the axial bearing 12, the axial force acts on the first support surface 17 of the sensor mount 11. Since the second support surface 18 is radially offset, a bending occurs on the sensor mount 11, which can then be measured by the pressure sensor 10. In other words, the sensor mount 11 is supported via the second support surface 18 in such a way that a force acting on the first support surface 17 results in a kind of deflection of the sensor mount 11.

[0057] In the illustrated embodiment, the sensor receptacle 11 further comprises an outer surface 22 and a second surface 23. The second surface 23 is annular with a larger diameter than the first annular surface 17 and essentially serves as a bearing surface. The housing 20 and the bearing point 6 form a bearing receptacle 21 for the sensor receptacle 11. The outer surface 22 is cylindrical and fits into the bearing receptacle 21 of the housing 20. The second surface 23 is also supported on the housing 20, and the second annular surface 18 is supported at the bearing point 6, as mentioned above.

[0058] In the illustrated embodiment, the bearing point 6 is indirectly provided by the housing 20. The second support surface 18 rests on a shoulder 27 on the housing via the outer rings of further ball bearings 26. In other embodiments, it would also be conceivable for the bearing point 6 to be provided directly by the housing 20, so that the second support surface 18 is directly supported on the housing 20.

[0059] The housing 20, as shown, is formed in multiple parts, comprising a front part 28 and a rear part 29. The front part 28 and the rear part 29 are connected to each other via a threaded connection 30. The aforementioned shoulder 27 is provided by the rear part 29, and the remainder of the bearing receptacle 21 is provided by the front part 28.

[0060] Of the Figures 3 and 4It is also evident that the force sensor 10 has a sensor cable 31 which is routed away through an interruption 32 in the further area 23 perpendicular to the sensor receptacle 11.

[0061] Based on the Figures 4 and 5 The shape of the sensor mount 11 according to the two embodiments shown will be further explained.

[0062] On the side of the sensor receptacle 11 facing the axial bearing 12 or the support area 5, the preferred configuration is as follows: The first support surface 17, which extends concentrically around the central opening 16, adjoins the central opening 16. The sensor surface 19 adjoins the first support surface 17. The sensor surface 19 is also annular and is offset from the first support surface 17 in the direction of the central axis M. In the installed state, the sensor surface 19 is spaced apart from the axial bearing 12, while the first support surface is in contact with the axial bearing 12. Furthermore, the sensor surface 19 extends concentrically to the central opening 16 and concentrically to the first support surface 17 completely around the central axis M. The force sensor 10 is positioned on the sensor surface 19.Concentric to sensor surface 19 is the further surface 23, which lies in the same plane as the first support surface 17. Viewed in cross-section through the central axis M, the plane transition between the first support surface 17 and the sensor surface 19 is essentially perpendicular to the support surface 17 and the sensor surface 19, respectively. The same applies to the plane transition between the sensor surface 19 and the further surface 23.

[0063] On the side of the sensor receptacle 11 facing the bearing point 6, the preferred configuration is as follows: A surface 33 adjoins the central opening 16, extending in a ring-like and concentric manner around the central opening 16. The second support surface 18 then adjoins the surface 33. Viewed along the central axis M, the surface 33 is located at a smaller distance from the first support surface 17 than the second support surface 18. The transition from the surface 33 to the second support surface 18 is arranged perpendicular to the central axis in cross-section. The transition thus has a conical shape, which can reduce stress concentrations.

[0064] The sensor mount is preferably made of steel, such as 100Cr6 or 42CrMo4. REFERENCE MARK LIST

[0065] 1 Pressing device 27 Paragraph 2 drive element 28 Front part 3 Drive section 29 Rear 4 spindle 30 threaded connection 5 support area 31 Sensor cable 6 Storage site 32 Interruption 7 Press piston 33 Area 8 Tool holder M central axis 9 Sensor unit F Axial force 10 Force sensor 11 Sensor recording 12 Axial bearing 13 first bearing ring 14 second bearing ring 15 rolling elements 16 opening 17 first support surface 18 second support surface 19 Sensor area 20 Housing 21 Storage 22 outdoor area 23 additional area 24 Spindle nut 25 Press rollers 26 ball bearings

Claims

1. Pressing device (1) comprising a drive element (2) with an output section (3), a spindle gear driven by the output section (3) with a spindle (4) defining a central axis (M) and a spindle nut, wherein either the spindle (4) or the spindle nut (24) has a support area (5) via which the spindle (4) or the spindle nut (24) is supported at a bearing point (6), a press piston (7) driven by the spindle gear, and a tool holder (8) for holding a pressing tool, wherein the pressing device (1) further comprises a sensor unit (9) for measuring an axial force (F) acting in the direction of the central axis (M), wherein the sensor unit (9) comprises a force sensor (10) and a sensor mount (11), wherein the sensor mount (11) is connected to the spindle (4) and the bearing point (6) or with the spindle nut (24) and the bearing point (6) in such a way that the sensor mount (11) is loaded with the said axial force during a pressing operation and that the axial force can be detected with the force sensor (10), wherein an axial bearing (12) is further arranged between the bearing point (6) and the support area (5) in such a way that the spindle (4) or the spindle nut (24) is supported via the axial bearing (5) with respect to forces acting in the direction of the central axis at the bearing point (6), wherein the sensor mount (11) is in contact with the axial bearing (12) in such a way that the axial force can be introduced into the sensor mount (11), wherein the axial bearing (12) is an axial ball bearing with a first bearing ring (13) and a second bearing ring (14) as well as rolling elements (15) arranged between the bearing rings (13, 14), characterised in that the sensor mount (11) is ring-shaped with a central opening (16), wherein the sensor mount (11) has a first support surface (17) and a second support surface (18), wherein the first bearing ring (13) is in contact with the support area (5), wherein the second bearing ring (14) is in contact with the first support surface (17) and wherein the second support surface (18) is in contact with the bearing point (6); or wherein the first support surface (17) is in contact with the support area (5), wherein the second support surface (18) is in contact with the first bearing ring (13) and wherein the second bearing ring (14) is in contact with the bearing location (6).

2. Pressing device (1) according to claim 1, characterised in that the sensor mount (11) is arranged between the bearing point (6) and the support area (5).

3. Pressing device (1) according to claim 1 or 2, characterised in that the axial bearing (12) is in contact with the support area (5) and that the sensor mount (11) is in contact with the axial bearing (12) and with the bearing point (6); or that the sensor mount (11) is in contact with the support area (5) and the axial bearing (12) is in contact with the sensor mount (11) and the bearing location (6).

4. Pressing device (1) according to one of the preceding claims, characterised in that the first support surface (17) is spaced apart from the second support surface (18) in a direction parallel to the central axis (M) and in a direction transverse to the central axis (M).

5. Pressing device (1) according to one of the preceding claims, characterised in that the support surfaces (17, 18) are designed as ring surfaces, wherein the ring surfaces preferably run concentrically around the central axis (M), and / or the first support surface (17) has an outer diameter which is smaller than an inner diameter of the second support surface (18).

6. Pressing device (1) according to one of the preceding claims, characterised in that the force sensor (10) is arranged on a sensor surface (19) on the sensor mount (11), the sensor surface (19) preferably lying in a plane extending at right angles to the central axis (M).

7. Pressing device (1) according to claim 6, characterised in that the sensor surface (19) is arranged and designed in such a way that the sensor surface (19) is subjected to a bending load when the said axial force is applied.

8. Pressing device according to one of the preceding claims, characterised in that said sensor surface (19) is offset radially and axially to the central axis (M) relative to the first support surface (17) and said sensor surface (19) is offset radially and axially to the central axis relative to the second support surface (18) and / or in that the sensor surface (19) is located on the side of the first support surface (17) and thus opposite the second support surface (18), or that the sensor surface (19) is located on the side of the second support surface (18) and thus opposite the first support surface (17).

9. Pressing device (1) according to one of the preceding claims, characterised in that the force sensor (10) is a strain gauge and / or an inductive force transducer and / or a piezoelectric force transducer.

10. Pressing device (1) according to one of the preceding claims, characterised in that the pressing device (1) further comprises a housing (20) which directly or indirectly provides the said bearing point (6).

11. Pressing device (1) according to claim 10, characterised in that the sensor mount (11) is mounted axially and radially in a bearing mount (21) in the housing (20).

12. Pressing device (1) according to claim 10, characterised in that the bearing point (6) forms part of the bearing mount and that the sensor mount (11) is in contact with an outer surface (22), with the second support surface (18) via the bearing point (6) and with a further surface (23) with the bearing mount (21).