LINEAR GUIDING SYSTEM

Abstract

A linear guide system including a first rail element and a second rail element mounted so as to be linearly displaceable relative to one another in and against a pull-out direction. A spindle drive includes a threaded spindle and a spindle nut running on the threaded spindle. The threaded spindle is mounted rotatably about a spindle axis on the first rail element or on a device fixed in or against the pull-out direction relative to the first rail element. The spindle nut is fixed in and against the pull-out direction on the second rail element, so that the spindle nut moves along the threaded spindle during a rotational motion of the threaded spindle and entrains the second rail element. The second rail element carries a spindle bearing fixed in or against the pull-out direction relative to the second rail element. that is arranged and positioned such that the spindle bearing guides the threaded spindle relative to the second rail element.

Claims

1: A linear guide system comprising a first rail element and a second rail element, wherein the first rail element and the second rail element are mounted so as to be linearly displaceable relative to one another in and against a pull-out direction, a spindle drive comprising a threaded spindle and a spindle nut running on the threaded spindle, wherein the threaded spindle is mounted rotatably about a spindle axis on the first rail element or is mounted rotatably about the spindle axis on a device fixed in or against the pull-out direction relative to the first rail element, and wherein the spindle nut is fixed to the second rail element in and against the pull-out direction, so that the spindle nut moves along the threaded spindle during a rotary motion of the threaded spindle about the spindle axis and entrains the second rail element, characterised in that the second rail element carries a spindle bearing fixed in or against the pull-out direction relative to the second rail element, wherein the spindle bearing is arranged and positioned such that the spindle bearing guides the threaded spindle at least in a first pull-out position of the second rail element relative to the first rail element with respect to the second rail element.

2: The linear guide system according to claim 1, wherein the spindle bearing comprises a bearing bush receiving the threaded spindle, wherein at least in the first pull-out position the threaded spindle is in a sliding engagement with the bearing bush during a relative motion of the threaded spindle with respect to the second rail element in or against the pull-out direction, so that the spindle bearing supports the threaded spindle.

3: The linear guide system according to claim 2, wherein the bearing bush comprises an axial length parallel to the pull-out direction, wherein the axial length of the bearing bush is smaller than a travel distance of the bearing bush relative to the threaded spindle between a maximum retracted pull-out position of the second rail element relative to the first rail element and a maximum extended pull-out position of the second rail element relative to the first rail element.

4: The linear guide system according to claim 3, wherein the bearing bush is positioned on the second rail element in such a way that in the maximum extended pull-out position of the second rail element relative to the first rail element, the bearing bush is out of engagement with the threaded spindle.

5: The linear guide system according to claim 4, wherein the bearing bush comprises a distance (d) of 50 mm or less from the spindle nut in a direction parallel to the pull-out direction.

6: The linear guide system according to claim 2, wherein the spindle bearing comprises a lead-in area, wherein the lead-in area adjoins the bearing bush against the pull-out direction and widens starting from a diameter of the bearing bush against the pull-out direction, wherein, during operation of the guide system, a free end of the threaded spindle can be moved through the lead-in area into the bearing bush.

7: The linear guide system according to claim 1, wherein the second rail element comprises a rail back and two running surfaces for rolling elements carrying legs extending at an angle relative to the rail back, wherein the spindle bearing is formed by a bearing block with the bearing bush receiving the threaded spindle and a mounting section, and wherein the mounting section is clamped between the two legs at least in a force-fit manner.

8: The linear guide system according to claim 7, wherein the mounting section comprises a projection or recess, wherein the rail back of the second rail element comprises a recess complementary thereto or a projection complementary thereto, so that the bearing block is positively fixed to the second rail element in and against the pull-out direction.

9: The linear guide system according to claim 7, wherein the legs of the second rail element and the mounting section of the bearing block are arranged in such a way that the legs press the bearing block against the rail back.

10: The linear guide system according to claim 2, wherein the bearing bush is open in sections towards the first rail element.

11: The linear guide system according to claim 1, wherein the spindle nut is floatingly received on the second rail element in at least one direction perpendicular to the pull-out direction.

12: The linear guide system according to claim 1, wherein the linear guide system comprises an electric motor, and wherein the threaded spindle is operatively coupled to the electric motor such that the electric motor sets the threaded spindle into a rotational motion during operation of the linear guide system.

13: The linear guide system according to claim 12, wherein the threaded spindle is mounted on the first rail element exclusively via the electric motor.

Description

[0054] Further advantages, features and possible applications of the present invention become apparent from the following description of an embodiment and the associated figures. In the figures, identical elements are denoted by identical reference numbers.

[0055] FIG. 1 is an isometric, partially transparent view of a telescopic rail according to the invention from diagonally above in the fully retracted state.

[0056] FIG. 2 is an isometric, partially transparent view of the telescopic rail of FIG. 1 in the fully extended state.

[0057] FIG. 3 is a sectional view through the telescopic rail from FIGS. 1 and 2 along line A-A of FIG. 1.

[0058] FIG. 4 is an isometric view of an embodiment of a spindle bearing for the telescopic rail of FIGS. 1 to 3.

[0059] FIG. 5 is a top view from below of the spindle bearing of FIG. 4.

[0060] FIG. 6 is a front view of the spindle bearing of FIGS. 3 and 4.

[0061] FIG. 7 is a sectional view through the spindle bearing of FIGS. 3 to 6 along line B-B of FIG. 6.

[0062] FIGS. 1 to 7 illustrate a variant of a linear guide system according to the invention in the form of a telescopic pull-out 4. The telescopic pull-out 4 is a full extension with a first rail element 1, a second rail element 2 and a third rail element 3. FIG. 1 shows the telescopic pull-out 4 in its fully retracted state, while FIG. 2 shows a representation of the fully extended state, in which the third rail element 3 no longer overlaps with the first rail element 1 in the pull-out direction 5.

[0063] The second rail element 2 forms a centre rail, which is mounted both on the first stationary rail element 1 and movable relative to it in and against the pull-out direction and is also mounted on the third rail element 3 so as to be movable in and against the pull-out direction.

[0064] The first rail element 1 and the third rail element 3 each comprise a C-shaped profile. A rail back 11 connects two respective legs 12a, 12b. The legs 12a, 12b form running surfaces 13 that point towards each other. Rolling elements in the form of bearing balls 14 roll on the running surfaces 13. These bearing balls 14 simultaneously roll on the running surfaces 13 of the second rail element 2. The second rail element 2 consists of two C-shaped profiles that are connected to each other at their backs 15.

[0065] The telescopic pull-out 4 is motorised by means of an electric motor 6, so that the second rail element 2 moves automatically relative to the first rail element 1 and the third rail element 3 moves automatically relative to the second rail element 2. The electric motor 6 drives a rotary motion of a threaded spindle 7 coupled to the electric motor 6 or its motor shaft. The threaded spindle 7 is clearly recognisable in the cross-sectional view of FIG. 3.

[0066] A spindle nut (not shown in the figures) is fixed to the second rail element 2 so that it cannot rotate. In addition, the spindle nut is fixed to the second rail element 2 in and against the pull-out direction 5. Therefore, a rotary motion of the threaded spindle 7 leads to a linear motion of the spindle nut and thus of the second rail element 2 relative to the first rail element 1. The simultaneous, synchronous extension motion of the third rail element 3 relative to the second rail element 2 is achieved by synchronisation via a belt drive, as described in detail in European patent EP 3 919 770 B1.

[0067] The threaded spindle 7 is only mounted on the stationary first rail element 1 via the electric motor 6.

[0068] While the spindle nut 21 is fixed against rotation relative to the second rail element and in and against the pull-out direction on the second rail element 2, the spindle nut 21 is floatingly mounted on the second rail element 2 in two directions perpendicular to each other and perpendicular to the pull-out direction 5, namely in the upward direction 8 and in the direction perpendicular thereto 9.

[0069] Without the spindle bearing 10 according to the invention, this clearance of the threaded nut with respect to the second rail element 2 in the directions 8 and 9 leads to the threaded spindle 7 being able to wobble and/or vibrate almost unhindered with respect to the second rail element 2. However, such a wobbling or vibrating movement of the threaded spindle 7 may lead to noise when the threaded spindle 7 strikes against the second rail element 2 or the first rail element 1 and to vibrations, which may also be transmitted to the elements connected to the telescopic pull-out 4. Therefore, according to the invention, the spindle bearing 10 is provided on the second rail element 2.

[0070] The structure and function of the spindle bearing 10 is now described with reference to the enlarged illustrations of the spindle bearing 10 in FIGS. 4 to 7. The spindle bearing 10 is attached to the second rail element 2 at the position of the second rail element 2 labelled with line A-A in FIG. 1. In this way, when the second rail element 2 is extended relative to the first rail element 1, the spindle bearing 10 moves along the threaded spindle until the threaded spindle slips out of the spindle bearing. In this way, the threaded spindle 7 is optimally supported over a large part of its travel. Surprisingly, the fact that the threaded spindle 7 slips out of the spindle bearing shortly before reaching the maximum extended pull-out position (see FIG. 2) does not impair the running behaviour of the telescopic pull-out 4.

[0071] The spindle bearing 10 is a bearing block 17 made of POM by injection moulding, which is arranged in one piece and is mounted on the second rail element 2 during system integration. The bearing block 17 consists of a two-part mounting section 16a, 16b and a bearing bush 18. The mounting section 16a, 16b clamps the bearing block 17 between the legs 12a, 12b carrying the running surfaces 13 of the second rail element 2. Due to the C-shaped profile of the second rail element 2, the mounting section 16a, 16b of the bearing block 17 is clamped to the second rail element 2 in such a way that the bearing block 17 is pressed towards the back of the rail 15 of the second rail element 2. The two parts of the mounting section 16a, 16b lead to a form-fit connection between the bearing block 17 and the second rail element 2 in the upward direction 8. In contrast, the mounting section 16a, 16b in the pull-out direction 5 only causes a force-fit due to the static friction between the surface of the mounting section 16a, 16b and the legs 12a, 12b of the second rail element 2. In order to additionally provide a positive fit between the bearing block 17 and the second rail element 2 in and against the pull-out direction 5, the mounting section also comprises a projection 16c, which engages positively in the rail back 15 of the second rail element 2 and reliably absorbs all forces that are introduced into the bearing block 17 in and against the pull-out direction 5.

[0072] So that the bearing block 17 mounted on the second rail element 2 can fulfil its bearing function, it comprises a bearing bush 18. The bearing bush 18 is a cylindrical inner wall section 19 of the bearing block 17. The radius of the inner wall section 19 is dimensioned in such a way that the threaded spindle 7 performs a sliding movement relative to the inner wall section 19 and yet the threaded spindle 7 is supported in the radial direction. The bearing block 17 further comprises a lead-in area 20, wherein in the lead-in area 20 the inner wall section widens outwards in a frustoconical shape starting from the nominal radius of the inner wall section 19 of the bearing bush 18, i.e. against the pull-out direction 5. In this way, the front, free end of the threaded spindle 7 can run back into the bearing bush 18 after leaving it when the second rail element 2 is retracted against the pull-out direction 5.

[0073] In the embodiment shown, the bearing block 17 is symmetrical, i.e. it also widens on the side of the bearing bush 18 facing away from the lead-in area 20. The symmetry merely serves to avoid having to pay attention to the orientation of the bearing block 17 during assembly.

[0074] The cylindrical inner wall section 19 is open towards the back of the first rail element 1. In other words, the surface 19 does not form a complete cylinder. However, the inner wall section 19 surrounds the threaded spindle 7 by approximately 270. This can be clearly seen in the sectional view in FIG. 6. Opening the bearing bush 18 towards the rail back 11 of the first rail element 1 reduces the size of the bearing for the threaded spindle 7. This is necessary because the ball cage, which guides the bearing balls 14, must also run in the space between the rail back of the second rail element 2 and the rail back of the first rail element 1.

[0075] For the purposes of the original disclosure, it is pointed out that all features, as they are apparent to a person skilled in the art from the present description, the drawings and the claims, even if they have been described specifically only in connection with certain further features, can be combined both individually and in any combination with other features or groups of features disclosed herein, unless this has been expressly excluded or technical circumstances make such combinations impossible or meaningless. A comprehensive, explicit description of all conceivable combinations of features is omitted here only for the sake of brevity and readability of the description.

[0076] Whilst the invention has been illustrated and described in detail in the drawings and the preceding description, this illustration and description is given by way of example only and is not intended to limit the scope of protection as defined by the claims. The invention is not limited to the disclosed embodiments.

[0077] Variations of the disclosed embodiments will be obvious to those skilled in the art from the drawings, the description and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article one or a does not exclude a plurality. The mere fact that certain features are claimed in different claims does not exclude their combination. Reference numbers in the claims are not intended to limit the scope of protection.

LIST OF REFERENCE NUMBERS

[0078] 1 first rail element [0079] 2 second rail element [0080] 3 third rail element [0081] 4 telescopic pull-out [0082] 5 pull-out direction [0083] 6 electric motor [0084] 7 threaded spindle [0085] 8 upward direction [0086] 9 direction perpendicular to the upward direction and to the pull-out direction [0087] 10 spindle bearing [0088] 11 rail back [0089] 12a, 12b leg [0090] 13 running surfaces [0091] 14 bearing ball [0092] 15 rail back [0093] 16a, 16b mounting section [0094] 16c projection [0095] 17 bearing block [0096] 18 bearing bush [0097] 19 inner wall section [0098] 20 lead-in area [0099] 21 spindle nut