Scanning unit of a position measuring device

Abstract

The invention relates to a scanning unit (10) of a position measuring device (100). The scanning unit (10) comprises a housing (12), a plurality of through-holes (14) arranged in the housing (12) for fixing the scanning unit (10) to the object (1), and a plurality of fixing elements (16) extending through the through-holes (14). The scanning unit (10) has a plurality of flexible elements (18). The flexible element (18) extends at least partially through the through hole (14). The flexible element (18) is designed to press the housing (12) of the scanning unit (10) against the reference element (2).

Description

Technical Field

[0001] The invention relates to a scanning unit for a position measuring device according to the preamble of claim 1 . Background Art

[0002] DE 10 2014 213 955 A1 discloses a device having a scanning unit and a mounting aid, with which the scanning unit can be rotated about a rotation axis of a reference element. The mounting aid is designed to elastically press the scanning unit onto the reference element.

[0003] WO 02 / 40947 A1, US Pat. No. 4,639,595 A, DE 4304914 A1 and EP 2905582 A1 disclose a method for connecting a scanning unit to a measuring tool. Other devices that fix the relative position between them. Summary of the invention

[0004] The object of the present invention is to provide a scanning unit for a position measuring device which is compact and cost-effective and which allows simple installation with high precision. This object is achieved according to the invention by a scanning unit having the features of claim 1 .

[0005] The scanning unit constructed according to the present invention comprises a housing, one or more through holes arranged in the housing for fixing the scanning unit on an object, and one or more fixing elements extending through the through holes. The scanning unit has one or more flexible elements. The one or more flexible elements extend at least partially through the through holes. The one or more flexible elements are configured to press the housing of the scanning unit onto the reference element.

[0006] Preferably, a prestressing device is formed by the flexible element and the fixing element. The prestressing device can also be referred to as an assembly aid.

[0007] Advantageously, the flexible element is designed to generate a predetermined contact pressure force, by which the housing of the scanning unit is pressed against the reference element.

[0008] Furthermore, it is advantageous if the flexible element is designed to prestress the fastening element in the through-opening in such a way that a predetermined contact pressure force is generated.

[0009] The flexible element is preferably designed in a tubular manner (for example in a hollow cylindrical manner).

[0010] Preferably, the flexible element is an elastically deformable element, for example, the flexible element is made of silicone or rubber.

[0011] Preferably, the fixing element is designed as a fixing screw or a fastening bolt.

[0012] Claim 11 describes a measuring tool and a position measuring device for a scanning unit according to the invention.

[0013] It is advantageous if the position-measuring device has a reference element and if the reference element is arranged between the measuring standard and the scanning unit.

[0014] Preferably, the reference element is a flexible membrane with a predetermined thickness and / or a predetermined curvature. For example, the predetermined thickness corresponds to the spacing between the gauge and the scanning unit. In addition, the predetermined curvature is matched, for example, to the radius or diameter of the gauge (in the case of a rotary position measuring device). In the case of a linear position measuring device, the flexible membrane can be matched to the plane of the measuring scale of the gauge. The flexible membrane is advantageously used as a spacing element.

[0015] By means of the present invention, a simple assembly of a position measuring device can be achieved using a scanning unit that is compactly and cost-effectively constructed. The position measuring device comprises a gauge and a scanning unit. When assembling the position measuring device, a high-precision, that is, an accurate (or substantially error-free) adjustment of the spacing between the gauge and the scanning unit (hereinafter referred to as the scanning gap) is achieved. The assembly, for example, comprises the following steps: (i) arranging a reference element between the gauge and the scanning unit; (ii) fixing the scanning unit on an object in a fixed position so that the housing of the scanning unit is pressed onto the reference element by a flexible element integrated in the scanning unit; and (iii) removing the reference element from the gauge and the scanning unit. The present invention in particular allows the scanning unit to be pressed (or flexibly spring-loaded) onto the reference element in a limited manner. Thus, errors or inaccuracies caused by manual pressing of the scanning unit, for example, not in accordance with operating procedures, can be avoided during assembly. Therefore, a high-precision assembly or an error-free adjustment of the scanning gap is achieved.

[0016] Advantageous embodiments of the invention are apparent from the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further details and advantages of the present invention are explained with the aid of the following description of embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0018] Figure 1 shows a perspective exploded view of a position measuring device according to a first exemplary embodiment, the position measuring device having a continuous flexible element;

[0019] Figure 2shows a perspective exploded view of a position measuring device according to a second exemplary embodiment, the position measuring device having a continuous flexible element;

[0020] Figure 3 Shown in accordance with Figure 2 A side view of a position measuring device having a section line AA and a section line BB;

[0021] Figure 4a Shown along Figure 3 Section view of the cutting line AA in;

[0022] Figure 4b Shown along Figure 3 A cross-sectional view of the cutting line BB in FIG.

[0023] Figure 5a Shown and according to Figure 4a a cross-sectional view similar to the cross-sectional view of , the cross-sectional view having a flexible member with a first pair of segments;

[0024] Figure 5b Shown and according to Figure 4b a cross-sectional view similar to the cross-sectional view of , having a flexible element with a second pair of segments;

[0025] Figure 6a Shown and according to Figure 4a having a flexible element with a single segment; and

[0026] Figure 6b Shown and according to Figure 4b A cross-sectional view similar to the cross-sectional view of , which has a flexible element with a single segment. DETAILED DESCRIPTION

[0027] Identical elements or elements with the same function are provided with the same reference symbols in the figures.

[0028] The following uses Figure 1 The first embodiment is explained below. The position measuring device 100 according to the first embodiment is particularly a rotary position measuring device. Figures 2 to 4b The second embodiment is explained below. The position measuring device 100 according to the second embodiment is particularly a linear position measuring device. Figure 5a and 5b 2 shows an exemplary first alternative design of the flexible element 18 of the position measuring device 100 according to the second exemplary embodiment (hereinafter referred to as the third exemplary embodiment). Figure 6a and 6b2 shows an exemplary second alternative embodiment of flexible element 18 of position measuring device 100 according to the second exemplary embodiment (hereinafter referred to as fourth exemplary embodiment).

[0029] according to Figure 1 The position measuring device 100 comprises a measuring tool with a measuring scale 4.1 and a scanning unit 10. The scanning unit 10 is used to scan the measuring scale 4.1 of the measuring tool. Figure 1 The scale carrier of the measuring tool is not shown.

[0030] In addition, according to Figure 1 The position measuring device 100 comprises a reference element 2. The reference element 2 is arranged between the measuring scale 4.1 of the measuring tool and the scanning unit 10. The reference element 2 is used as a spacing element (for example, a flexible film with a predetermined thickness). The reference element 2 can be removed from the measuring scale 4.1 of the measuring tool and the scanning unit 10 when the scanning unit 10 is installed (that is, when it is fixed to the object 1).

[0031] As in Figure 1 As shown in the figure, the scanning unit 10 includes a housing 12, a plurality of through holes 14 (first and second through holes 14.1, 14.2) arranged in the housing 12, and a plurality of fixing elements 16 (first and second fixing elements 16.1, 16.2). The through holes 14 are used to fix the scanning unit 10 on the object 1. The fixing elements 16 are configured as fixing screws or fixing bolts and extend through the through holes 14. In addition, Figure 1 , the scanning unit 10 has a plurality of flexible elements 18 (first and second flexible elements 18.1, 18.2). The flexible elements 18 extend at least partially through the through-hole 14. The flexible elements 18 are configured to press the housing 12 of the scanning unit 10 onto the reference element 2. A predetermined pressing force is Figure 1 This is indicated by arrow F in FIG.

[0032] In addition, Figure 1 , it is shown that the scanning unit 10 has a plurality of washers 20 (first and second washers 20 . 1 , 20 . 2 ), through which the fastening element 16 extends.

[0033] exist Figure 1 . The first direction P1 and the second direction P2 are shown in FIG. The first direction P1 is perpendicular to the surface 2.1 of the reference element 2. The second direction P2 is perpendicular to the surface 1.1 of the object 1. The predetermined pressing force F is parallel to the first direction P1. The first direction P1 and the second direction P2 are two mutually orthogonal directions.

[0034] In addition, Figure 1 2 shows a section 22 of the cable of the scanning unit 10 .

[0035] The position measuring device according to the second embodiment differs from the position measuring device according to the first embodiment in that the measuring tool 4 with the measuring scale 4.1 is a ruler (that is, a linear ruler). The reference element 2 is arranged between the measuring tool 4 in the form of a linear ruler and the scanning unit 10 (see Figure 2 The reference element 2 is used in turn as a distance-keeping element for adjusting the distance between the measuring standard 4 and the scanning unit 10 (that is, between the measuring standard 4 and the scanning unit 10). Figure 3 For example, the reference element 2 is a flexible membrane with a predetermined thickness. In this case, the predetermined thickness corresponds to the distance L (see Figure 3 ).

[0036] exist Figure 2 3 again shows the predetermined pressing force F as well as the first direction P1 and the second direction P2.

[0037] exist Figure 4a The first fixing element 16.1 and the first flexible element 18.1 are shown in the cross-sectional view of FIG. Figure 4a The longitudinal axis S1 of the first fixing element 16.1 is shown in FIG. The longitudinal axis S1 extends parallel to the second direction P2. Figure 4b The second fixing element 16.2 and the second flexible element 18.2 are shown in the cross-sectional view of Figure 4b 2. The longitudinal axis S2 of the second fastening element 16.2 is shown in FIG. The longitudinal axis S2 extends parallel to the second direction P2.

[0038] Reference Figure 4a , a part of the pre-tensioning device is formed by the first flexible element 18.1 and the first fixing element 16.1. Figure 4b The second flexible element 18.2 and the second fixing element 16.2 form another part of the preload device. In general, the predetermined pressing force F (see Figure 2 ). Thus, the housing 12 of the scanning unit 10 is pressed against the reference element 2 in a defined manner by the prestressing device. The predetermined pressing force F is generated essentially in the center between the section line AA and the section line BB (see Figure 2 and 3 ).

[0039] As can be seen in Figure 2As can be seen in FIG. 1 , flexible element 18 is designed to press housing 12 of scanning unit 10 against reference element 2 along a first direction P1 .

[0040] Reference Figure 2 , 4a 4b, the flexible element 18 extends along the second direction P2 inside the through hole 14. Figure 2 , 4a As can be seen in FIG. 4 b , the flexible element 18 , ie the first and second flexible elements 18 . 1 , 18 . 2 , is designed to be continuous or continuous along the second direction P2 .

[0041] exist Figure 5a The first fixing element 16.1 and the first pair of segments 18.11, 18.12 are shown in a sectional view of FIG. The first pair of segments 18.11, 18.12 form the first flexible element 18.1 (here in an exemplary first alternative design). Figure 5a The cross-section diagram basically corresponds to Figure 4a Cross-sectional view of .

[0042] exist Figure 5b The second fixing element 16.2 and the second pair of segments 18.21, 18.22 are shown in FIG. The second pair of segments 18.21, 18.22 form a second flexible element 18.2 (here in the exemplary first alternative design). Figure 5b The cross-section diagram basically corresponds to Figure 4b Cross-sectional view of .

[0043] Reference Figure 5a and 5b , the flexible element 18 thus has a first pair of segments 18.11, 18.12 and a second pair of segments 18.21, 18.22. Figure 5a and 5b As can be seen in the figure, the first pair of segments 18.11, 18.12 and the second pair of segments 18.21, 18.22 are respectively arranged at two ends of the through hole 14 that are opposite to each other along the second direction P2. The exemplary first alternative design achieves a particularly cost-effective and nevertheless stable structure.

[0044] exist Figure 6a The sectional view of shows the first fixing element 16.1 and the single section 18.11. The single section 18.11 forms the first flexible element 18.1 (here in the exemplary second alternative embodiment). Figure 6a The cross-section diagram basically corresponds to Figure 4a Cross-sectional view of .

[0045] exist Figure 6b The sectional view of shows the second fixing element 16.2 and the single section 18.22. The single section 18.22 forms the second flexible element 18.2 (here in the exemplary second alternative embodiment). Figure 6b The cross-section diagram basically corresponds to Figure 4b Cross-sectional view of .

[0046] Reference Figure 6a and 6b , the flexible element 18 thus has a single segment 18.11 or a single segment 18.22. The single segment 18.11 and the single segment 18.22 are each arranged at the end of the through hole 14 facing away from the object 1. By means of the exemplary second alternative design, a more cost-effective and nevertheless more stable structure is achieved compared to the exemplary first alternative design.

[0047] In the first and second exemplary embodiments, the flexible element 18 is designed in the form of a tube (see Figure 1 ; Figure 2 , 4a Furthermore, the flexible element 18 can also have one or more hose-like sections (see Figure 5a and 5b , the third embodiment; Figure 6a and 6b , fourth embodiment). The flexible element 18 is, in particular, an elastically deformable element, for example, made of silicone or rubber.

[0048] Alternatively, the flexible element 18 can be designed differently in the through-opening 14 (for example, continuously in the first through-opening 14 . 1 and interrupted in the second through-opening 14 . 2 , or vice versa).

[0049] As can be seen in Figure 4a , 4b , Figure 5a , 5b , Figure 6a , 6b As can be seen in FIG. 1 , the flexible element 18 has a first extension D1 parallel to the first direction P1. In addition, the through hole 14 has a second extension D2 parallel to the first direction P1. For example, the first extension D1 is less than half of the second extension D2.

[0050] In all embodiments, the flexible element 18 has a first (outer) diameter (corresponding, for example, to the first extension D1). Furthermore, the fixing element 16 has a second diameter (i.e., the diameter of the shaft). For example, the first diameter is smaller than the second diameter. As can be seen in Figure 1 and 2 As can be seen in FIG. 1 , the through hole 14 has a shape / contour that matches the first and second diameters, respectively.

[0051] In another (fifth) embodiment, a single through hole is provided instead of a plurality of through holes 14. Furthermore, a single fixing element can be provided instead of a plurality of fixing elements 16. Furthermore, a single flexible element can be provided instead of a plurality of flexible elements 18.

[0052] In the fifth embodiment, the configuration / function of the different elements (i.e., the only through hole, the only fixing element and the only flexible element) is similar to that of the first to fourth embodiments. In addition, in the fifth embodiment, the different elements are advantageously arranged in the center of the scanning unit 10 (i.e., arranged in accordance with Figure 3 As a result, a predetermined pressing force F can be generated substantially in the center of the scanning unit 10 (similar to the first to fourth embodiments).

[0053] If measuring scale 4.1 is designed to be scannable optically, the invention allows particularly high-resolution position measurement. Alternatively, measuring scale 4.1 can also be designed to be scannable magnetically, inductively or capacitively.

Claims

1. A scanning unit (10) of a position measuring device (100), comprising: a housing (12), one or more through holes (14) arranged in the housing (12), the through holes being used to fix the scanning unit (10) on the object (1), and one or more fixing elements (16) extending through the through hole (14), It is characterized in that The scanning unit (10) has one or more flexible elements (18), wherein the one or more flexible elements (18) extend at least partially through the through hole (14), The one or more flexible elements (18) are designed to press the housing (12) of the scanning unit (10) against the reference element (2).

2. The scanning unit (10) according to claim 1, wherein a prestressing device is formed by the flexible element (18) and the fixing element (16).

3. A scanning unit (10) according to claim 1 or 2, wherein the flexible element (18) is constructed to generate a predetermined pressing force (F), by which the housing (12) of the scanning unit (10) is pressed against the reference element (2).

4. A scanning unit (10) according to any one of the preceding claims, wherein the flexible element (18) is configured to: press the housing (12) of the scanning unit (10) against the reference element (2) along a first direction (P1) perpendicular to the surface (2.1) of the reference element (2).

5. A scanning unit (10) according to any one of the preceding claims, wherein the flexible element (18) extends inside the through hole (14) along a second direction (P2) perpendicular to the surface (1.1) of the object (1), wherein the flexible element (18) is formed continuously along the second direction (P2).

6. A scanning unit (10) according to any one of claims 1 to 4, wherein the flexible element (18) has a first pair of segments (18.11, 18.12) and a second pair of segments (18.21, 18.22), wherein the first pair of segments (18.11, 18.12) and the second pair of segments (18.21, 18.22) are respectively arranged at two ends of the through hole (14) that are opposite to each other along a second direction (P2) perpendicular to the surface (1.1) of the object (1).

7. The scanning unit (10) according to claim 1, wherein the flexible element (18) is designed in a hose-like manner.

8. The scanning unit (10) according to any of the preceding claims, wherein the flexible element (18) is an elastically deformable element.

9. The scanning unit (10) according to any of the preceding claims, wherein the flexible element (18) is made of silicone or rubber.

10. The scanning unit (10) according to claim 1, wherein the fixing element (16) is designed as a fixing screw or a fastening bolt.

11. Position-measuring device (100) having a measuring standard (4) and a scanning unit (10) according to one of the preceding claims.

12. The position measuring device (100) according to claim 11, wherein the position measuring device (100) comprises the reference element (2), wherein the reference element (2) is arranged between the measuring standard (4) and the scanning unit (10).

13. The position-measuring device (100) according to claim 12, wherein the reference element (2) is a spacer element for adjusting a distance (L) between the measuring standard (4) and the scanning unit (10).

14. The position measuring device (100) according to claim 12 or 13, wherein the reference element (2) is a flexible film having a predetermined thickness.

15. The position measuring device (100) according to any one of claims 12 to 14, wherein the reference element (2) is removable from the measuring standard (4) and the scanning unit (10) when the scanning unit (10) is in an installed state.

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