Sensor for a ball screw drive and spindle nut having such a sensor

Abstract

A retrofit sensor for a spindle nut of a ball screw drive is disclosed. A plurality of bolts penetrate the flange of the spindle nut, which connect the flange to a table part or another component. The sensor can be easily clamped to the flange and fixed to the flange later, by loosening only a few of the bolts, preferably two, in the flange and clamping the sensor into these bolts.

Description

Technical Field

[0001] The invention relates to a sensor for a ball screw drive and a spindle nut for a ball screw drive having such a sensor. Background Art

[0002] Ball screw drives are known which convert the rotary drive motion of a spindle into a linear output motion of a spindle nut. The spindle nut is also called a ball screw drive nut (KGT nut). Between the two main components, balls are arranged rotating in a row, which (according to the principle of rolling bearings) reduce the friction between the two components to a minimum. The spindle nut often has a flange, to which the component to be moved linearly is fastened.

[0003] In order to detect wear and the resulting loss of precision or other damage on such ball screw drives and to be able to initiate remedial measures at an early stage so that (prolonged) functional interruptions do not occur, it is known from the prior art to provide sensors on the spindle nuts of such ball screw drives.

[0004] Document DE 10 2017 205 005 B3 discloses a strain gauge which is installed in a spindle nut and directly detects elastic deformations there.

[0005] Furthermore, it is known to place a sensor on the flange of the spindle nut.

[0006] According to the document "Sensorik an Kugelgewindetrieben, Losungen zurÜberwachung von Funktion und Betriebsverhalten" by A. Mannesmann, the sensor is placed radially on the flange of the spindle nut. The disadvantage of this is the radial free space that must be reserved over the entire stroke of the spindle nut for the sensor that is linearly displaced with the spindle nut.

[0007] In the document "Guard-Plus-Zustandsüberwachung von Kugelgewindetrieben" by Steinmeyer, the sensor is mounted on the end side of the flange. As a result, the sensor extends in the axial direction away from the end side of the flange. The wires of the sensor also extend in this direction. As a result, the sensor with the wires extends the axial length of the spindle nut. The disadvantage of the last-mentioned sensor for ball screw drives is the shortening of the stroke for the spindle nut, which results from the extension of the axial length.

[0008] Another major disadvantage of all sensors of the prior art is that they cannot be retrofitted in a modular manner. Specifically, sensors of the prior art can only be retrofitted to already manufactured ball screw drives with a huge additional manufacturing outlay and can only be retrofitted to already operating ball screw drives when the ball screw drive is shut down and disassembled. Summary of the invention

[0009] In contrast, the object of the present invention is to provide a sensor for a ball screw drive and a spindle nut having such a sensor, wherein the sensor can be retrofitted in a modular manner and with minimal effort as a retrofit kit.

[0010] This object is achieved with respect to the sensor by the combination of features of claim 1 and with respect to the spindle nut by the combination of features of claim 8 .

[0011] Further advantageous embodiments of the invention are described in the dependent claims.

[0012] The sensor according to the present invention can also be referred to as a sensor device and has at least one, for example two, through-spaces, which are designed to be fixed on the end side of the spindle nut (ball screw transmission nut-KGT nut) of the ball screw transmission by means of at least one, for example two bolts. The design of the through-space can involve its size and / or its spacing relative to each other and / or the strength of the surrounding material. The design of the surrounding material can be achieved by two metal reinforcement sleeves. According to the present invention, the at least one bolt is also designed or can be used to fix a component to be driven or moved by the spindle nut, especially a workbench component. The component to be driven or moved can also be clamped together with the flange by other bolts of the same structure.

[0013] Similarly, the spindle nut (ball screw transmission nut - KGT nut) according to the invention is designed and suitable for use in a ball screw transmission. The spindle nut has a flange, and the sensor or sensor device is fixed to the end side of the flange by means of at least one bolt. For this purpose, the sensor and the flange each have at least one through-gap. The bolt is also designed and / or can be used to fix the component (especially the workbench part) to be driven or moved by the spindle nut. The flange can also be clamped together with the component to be driven or moved by other bolts of the same structure.

[0014] With these two inventive themes, the sensor or sensor device can be retrofitted as a retrofit assembly in a modular manner and with minimal effort. To this end, only the at least one screw mentioned must be loosened, by which the component to be moved is fixed to the flange. In this case, the component to be moved is fixedly connected to the flange by so-called additional screws. The removed screws can be reused and passed through the two through-holes of the sensor and tightened again. More precisely, the sensor is clamped together with the flange and the component to be moved by means of the screws.

[0015] In a preferred development of the spindle nut according to the invention, the at least one screw used according to the invention and the further screws have a regular arrangement on the pitch circle of the flange.

[0016] A preferred development of the sensor according to the invention or the spindle nut according to the invention has a housing which has a receptacle on the inside, into which the actual sensor unit is inserted. The receptacle can be an adhesive bag into which the sensor unit is glued.

[0017] The two through-openings can be formed in the two aforementioned metallic reinforcing sleeves in order not to adversely affect the two mechanical clamping chains which are preferably connected to the housing in a form-fitting manner.

[0018] The sensor unit is preferably a micro-electromechanical system (MEMS).

[0019] The sensor unit is preferably an acceleration sensor.

[0020] A plurality of sensor units may also be arranged in the housing.

[0021] In order to keep the stroke restriction of the spindle nut by the housing to a minimum, the housing has at least one, preferably two, recesses or openings, into which a screw head is respectively inserted.

[0022] An exemplary embodiment of the sensor according to the invention or of the spindle nut according to the invention has an adapter plate which is arranged between the end face and the housing and to which the housing is fastened.

[0023] In a first embodiment with an adapter plate, the housing is fastened to the adapter plate by means of two axial screws. These axial screws are preferably smaller than the screws used according to the invention and the (other) axial screws of the same structure. "Axial" means that the relevant screws are oriented parallel to the main axis when the sensor is fastened to the flange.

[0024] In a second embodiment with an adapter plate, the housing is fixed to the adapter plate by means of a form fit. Preferably, the adapter plate has a plurality of through-cuts through which the plastic of the wall of the housing extends.

[0025] In a development of the aforementioned exemplary embodiment with an adapter plate, the at least one screw head received in the at least one recess or depression is formed on the screw used according to the invention, by which the adapter plate is also fixed.

[0026] In a development of the aforementioned exemplary embodiment with an adapter plate, the housing has, on the side facing the adapter plate, a contact surface relative to the receptacle for the sensor, which contact surface is braced against the flange.

[0027] In a first embodiment with an adapter plate, the adapter plate has a recess for the contact surface, through which the plastic forming the contact surface extends—preferably with a gap—to the flange.

[0028] In a second embodiment with an adapter plate, the adapter plate has a plurality of through-cuts, which are preferably formed by holes with corresponding angles. The plastic forming the contact surface extends through the through-cuts to the flange and is connected there to the adapter plate in a form-fitting manner.

[0029] The housing has two projections on the side facing the adapter plate, which are supported on the adapter plate in order to generate a tilting moment of the housing when the housing is clamped. As a result, the contact surface is clamped against the flange as long as the contact surface is arranged on the side of the screw used according to the invention that is different from the two projections. In other words, the contact surface must then be arranged relative to the two projections with reference to the screw used according to the invention.

[0030] In another embodiment of the sensor according to the invention or the spindle nut according to the invention, the at least one screw head inserted into the at least one recess or depression is formed on one of the further screws which is not used for fixing the adapter plate according to the invention.

[0031] An energy store can be arranged in the housing. The energy store is preferably a cylindrical storage cell or a battery.

[0032] In order not to be subject to further travel restrictions, the connection for the electrical line is particularly preferably connected to the housing perpendicularly to the spindle and perpendicularly to the two screws used according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Various exemplary embodiments of the sensor according to the invention or the spindle nut according to the invention are shown in the drawings. In particular:

[0034] Figure 1 A perspective view shows a ball screw drive having a spindle nut according to the invention or a first exemplary embodiment of a sensor according to the invention;

[0035] Figure 2 A perspective view of a ball screw drive with a spindle nut according to the invention or a second exemplary embodiment of a sensor according to the invention;

[0036] Figure 3 Shown in perspective Figure 2 A housing of a second embodiment;

[0037] Figure 4 A third embodiment of the sensor according to the invention is shown in a perspective view;

[0038] Figure 5 Shown in perspective Figure 4 A housing according to a third embodiment of the present invention;

[0039] Figure 6 The exploded view shows Figure 4 A third embodiment of the sensor according to the present invention;

[0040] Figure 7 and 8 A housing and an adapter plate of a fourth exemplary embodiment of a sensor according to the present invention are shown in cross-sectional views, respectively; and

[0041] Fig. 9 A fourth exemplary embodiment of a sensor according to the invention is shown in an exploded view. DETAILED DESCRIPTION

[0042] Figure 1 and Figure 2 An embodiment of a sensor 3 or sensor arrangement according to the invention is shown in each case, which is fastened to a spindle nut 1 for detecting vibrations or uneven movements. This allows early detection of defects in a ball screw drive formed by the spindle nut 1 and the rotationally driven spindle 2. The spindle nut 1 is supported on the spindle 2 via balls (not shown) in such a way that friction is reduced to a minimum.

[0043] The spindle nut 1 has a flange 4, which is arranged in accordance with Figure 1 In a first embodiment, there are six through-slots and in accordance with Figure 2In the second embodiment of the present invention, eight through-holes are provided, into each of which a preferably identically constructed screw 6a, 6b is inserted. The components (not shown) or table parts that are to be linearly moved by the ball screw drive shown are fastened to the corresponding end sections of the screws 6a, 6b that are opposite the screw heads.

[0044] The housing 8 of the sensor 3 designed as a retrofit assembly is fastened in the manner according to the invention to the end face of the flange 4 which is opposite the component. For this purpose, two so-called screws 6a used in the invention, which are arranged mirror-symmetrically to each other, are loosened, wherein the component (not shown) is secured by the remaining (at Figure 1 In the middle four and Figure 2 The other six bolts 6b are kept in a clamped state with the flange 4. The two bolts 6a used according to the invention are pulled out of the flange, and then the housing 6 is placed on the end side of the flange 4, and the two bolts 6a used according to the invention are screwed back into their previous positions.

[0045] In accordance with Figure 1 In a first embodiment of the present invention, cylindrical batteries (not shown) are also introduced into the housing 8 .

[0046] Figure 3 Shows Figure 2 The second embodiment of the sensor 3 is the main part of the housing 8. The housing 8 has two through-holes 10, in which the Figure 3 Only one through-gap 10 can be seen in the figure. These through-gap 10 are respectively Figure 2 The screws 6 a used according to the invention are passed through, whereby the housing 8 is clamped against the end face of the flange 4 .

[0047] In order to keep the shortening of the path of the spindle nut 1 along the spindle 2 small, the housing 8 is designed such that it has a greater extension transversely to the lifting direction of the spindle nut 1 than in the lifting direction. For the same reason, two recesses 12 or cutouts are provided in the wall 16 facing the flange 4. Figure 2 and 3 In the second embodiment of each bolt head 14 is installed in the recess or the notch. In other words, the housing 8 also extends between these bolt heads 14 with its wall 16 facing the flange 4.

[0048] exist Figure 34 shows that a receiving portion 18 for the sensor unit is molded into the interior of the housing 8, immediately adjacent to the wall 16 facing the flange 4. The receiving portion 18 is preferably an adhesive pocket into which the sensor unit is poured by means of adhesive bonding in order to couple it to the housing 8 in a close fit. Figure 3 The main section shown in FIG. 1 , which has the wall 16 , the two through-openings 10 , the two recesses 12 and the receptacle 18 , is produced in one piece by injection molding. The two through-openings 10 can be reinforced by respective (not shown) metallic reinforcement sleeves.

[0049] Figure 4 A third embodiment of the sensor 3 according to the invention or the sensor device according to the invention is shown in a perspective view. A significant difference from the first two embodiments is that the screws 6a used according to the invention do not clamp the entire housing 8 but the adapter plate 20 against the end face of the flange 4. The housing 8 is in turn clamped against the adapter plate 20 by means of two screws 22.

[0050] Figure 5 The exploded view shows Figure 4 A third exemplary embodiment of the sensor 3 according to the invention or of the sensor device according to the invention is shown. It can be seen that the two screws 22 for clamping the housing 8 against the adapter plate 20 are smaller than the two screws 6a used according to the invention and thus also smaller than the further screws 6b. The two screws 22 are screwed only with their respective end sections into threaded sleeves 24 which are formed on the adapter plate 20 or are fastened thereto.

[0051] according to Figure 4 and 6 Another difference of the third embodiment with respect to the first two embodiments is that the two recesses 12 of the housing 8 are used to receive the screw heads 14 of the two screws 6a used according to the invention for fixing the sensor.

[0052] In order that the wall 16 of the housing 8 can come into contact with the end face of the flange 4 despite the wall of the adapter plate 20 and in order to transmit vibrations and shocks of the flange 4 as directly as possible to the sensor unit 25 , the adapter plate 20 has a recess 26 .

[0053] Figure 5 The perspective view shows in particular the wall 16 of the housing 8 that faces the adapter plate 20 or the flange 4. It can be seen that on the wall 16, the contact surface 28 protrudes in the direction of the flange 4, and the contact surface passes through the adapter plate 20 (at Figure 6 The recess 26 (shown in FIG. 1 ) extends therefrom.

[0054] In order to improve the clamping of the contact surface 28 toward the end face of the flange 4, two projections 30 are provided on the housing 8, wherein two screws 22 for fixing the housing 8 to the adapter plate 20 are arranged between the two projections 30 on the one hand and the contact surface 28 on the other hand. As a result, a tilting moment is applied to the housing 8 via the screws 22, so that the coupling of the sensor unit 25 to the flange 4 via the contact surface 28 is optimized.

[0055] Figure 7 and 8 The housing 8 and the metal adapter plate 20 of the fourth embodiment of the sensor according to the present invention are shown in cross-section. Figure 8 The housing 8 is shown as a semi-finished product or in the form of the housing 8 before it is fixed to the adapter plate 20 by a form fit. Figure 7 The housing 8 and the adapter plate 20 are shown as components of a positively connected connection.

[0056] The adapter plate 20 is fixed by injection molding or screwing directly to the housing 8. The adapter plate 20 is provided with correspondingly angled bores 36 for a stable connection to the housing 8. The adapter plate 20 is inserted into the injection mold before it is closed.

[0057] The adapter plate 20 can be designed as a sheet-metal part and / or as a bent part.

[0058] In accordance with Figure 8 In the fixed state, the section of the wall 16 of the housing 8 which extends through the bore 36 can be seen and which forms the contact surface 28 which is then clamped against the flange.

[0059] Fig. 9 A fourth exemplary embodiment of the sensor according to the invention is shown in an exploded view. A battery 34 is shown here, which in principle supplies power to all of the exemplary embodiments shown.

[0060] according to Figures 1 to 9 All the illustrated embodiments have a connection 32 for electric wires, which extends radially, that is, perpendicularly to the spindle longitudinal axis. Thus, the lifting stroke of the spindle nut 1 along the threaded spindle 2 is also maximized.

[0061] A retrofit sensor for a spindle nut of a ball screw drive is disclosed. A flange of the spindle nut is penetrated by a plurality of bolts, which connect the flange to a table part or another component. The sensor can be easily clamped to the flange and fixed to the flange later, in which only a few, preferably two, of the bolts are loosened and the sensor is clamped into these bolts.

[0062] List of reference numerals:

[0063] 1 Spindle nut

[0064] 2 Spindle

[0065] 3 Sensors

[0066] 4 Flange

[0067] 6a Bolt used according to the invention

[0068] 6b Additional bolts

[0069] 8 Housing

[0070] 10 Straight-through gap

[0071] 12 Recess

[0072] 14 Bolt head

[0073] 16 Wall

[0074] 18 Reception Department

[0075] 20 Adapter Plate

[0076] 22 Bolts

[0077] 24 Threaded sleeve

[0078] 25 sensor units

[0079] 26 Blank space

[0080] 28 Contact surface

[0081] 30 Bump

[0082] 32 Connectors

[0083] 34 Batteries

[0084] 36 Drilling

Claims

1. A sensor having at least one through-gap (10), the through-gap being designed to be fixed on the end side of a flange (4) of a spindle nut (1) of a ball screw transmission by means of at least one first bolt (6a), wherein the first bolt (6a) is also designed to fix a component to be driven by the spindle nut (1), and wherein the flange (4) can also be clamped to the component to be driven by another second bolt (6b) of the same structure, the sensor having a housing (8) and an adapter plate (20), the housing (8) being fixed on the adapter plate, wherein the housing (8) is disposed toward the adapter plate (20). The adapter plate (20) has a contact surface (28) on one side, which can be clamped toward the flange (4), wherein the adapter plate (20) has a recess (26) for the contact surface (28), and the housing has two projections on the side facing the adapter plate, which are supported on the adapter plate, wherein two third bolts (22) for fixing the housing (8) to the adapter plate (20) are arranged between the two projections (30) and the contact surface (28), and the two third bolts (22) are screwed into threaded sleeves (24) only with their respective end sections, and the threaded sleeves are formed on the adapter plate (20) or fixed thereto. 2 . The sensor according to claim 1 , wherein the housing has on its inner side a receptacle ( 18 ) for the sensor unit which is formed in one piece. 3 . The sensor according to claim 2 , wherein the housing ( 8 ) has at least one recess ( 12 ) into which a respective screw head ( 14 ) can be inserted.

4. The sensor according to claim 3, wherein the bolt head (14) is formed on the first bolt (6a), and the first bolt is also used to fix the adapter plate (20) on the flange (4).

5. The sensor according to claim 2, wherein the housing (8) has a contact surface (28) on the side facing the adapter plate (20) relative to the receptacle (18) for the sensor unit (25).

6. The sensor according to claim 3, wherein the bolt head (14) is formed on one of the further second bolts (6b).

7. A spindle nut (1) of a ball screw transmission, the spindle nut having a flange (4) and a sensor, wherein the sensor is fixed to the end side of the flange (4) by means of at least one through-gap (10) of the sensor and at least one first bolt (6a), wherein the first bolt (6a) is also designed to fix a component to be driven by the spindle nut (1), and wherein the flange (4) can also be clamped to the component to be driven by another second bolt (6b) of the same structure, the sensor having a housing (8) and an adapter plate (20), wherein the housing (8) is fixed to the adapter plate, wherein the housing (8) is disposed toward the The adapter plate (20) has a contact surface (28) on one side, which can be clamped toward the flange (4), wherein the adapter plate (20) has a recess (26) for the contact surface (28), and the housing has two projections on the side facing the adapter plate, which are supported on the adapter plate, wherein two third screws (22) for fixing the housing (8) to the adapter plate (20) are arranged between the two projections (30) and the contact surface (28), and the two third screws (22) are screwed into threaded sleeves (24) only with their respective end sections, and the threaded sleeves are formed on the adapter plate (20) or fixed thereto.

8. The spindle nut according to claim 7, wherein the first bolts (6a) and the further second bolts (6b) have a regular arrangement on a pitch circle of the flange (4).

9. The spindle nut according to claim 7 or 8, wherein the housing has a receptacle (18) formed in one piece on the inner side, into which the sensor unit is inserted.

10. The spindle nut according to claim 9, wherein the housing (8) has at least one recess (12) into which a respective screw head (14) is inserted.

11. The spindle nut according to claim 10, wherein the bolt head (14) is formed on the first bolt (6a), and the adapter plate (20) is also fixed by the first bolt.

12. The spindle nut according to claim 9, the housing (8) having a contact surface (28) on a side facing the adapter plate (20) relative to a receptacle (18) for the sensor unit (25).

13. The spindle nut according to claim 10, wherein the bolt head (14) is formed on one of the further second bolts (6b).

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