Slides for fast, high-precision movements

Abstract

Carriage for fast, high-precision movements of functional units (1) on strongly curved paths, which has a carriage body (10, 21, 27, 38) which is designed as a hollow body and consists of side walls (18, 28, 40) and base wall (19, 32) as well as cover wall (20, 25, 33, 42) and end wall (11, 22, 31, 43) and which is connected to a carrier (17, 24) via a guide system consisting of rails (13) and runners (14, 16), wherein at least one rail or two runners are arranged at each of the two outer ends of the base wall in the areas of overlap of the base wall with the side walls, characterized in that in the predominant part of the carriage body in cross sections perpendicular to the rails (13), the wall thickness of the base wall (19, 32) averaged over the cross section is less than 70% of the wall thickness over the wall thickness of the side walls (18, 28, 40) averaged over the cross section.

Description

[0001] In many machines and devices, functional units are moved using slide systems. These are used, for example, for processing, handling, or measuring workpieces. To perform their function, it is often necessary to move the functional units along spatial paths as quickly and precisely as possible. Forces caused by acceleration and interactions between the functional unit and workpieces act, particularly deforming the slide to which the functional unit is directly connected. Some of these deformations, together with the weight of this slide, limit the speeds at which the functional unit can be moved along paths with large curvatures without exceeding specified deviations from an ideal curve. The extent of the relevant deformations and the weight of the slide depend significantly on the shape of the slide body.The subject of the invention are slides with which particularly high-precision, fast movements of functional units on strongly curved paths can be generated by designing the slide bodies in a special way. State of the art

[0002] If low deformations are important, those slides to which a functional unit is directly connected have slide bodies that are designed as largely closed hollow bodies.

[0003] According to the state of the art, they have an approximately cuboid shape (DE10 2011 108 982 A1, DE10 2012 212 213 A1, DE 10 2007 015 152 A1) or an approximately tubular shape (DE10 2013 112 834 A1). The latter is adapted to a shape deviating from the tubular shape in some areas for the connection of guide systems or covers. Prism-shaped structures that taper evenly from one end to the other are also described (DE 10 2007 015 152 A1).

[0004] In the case of tubular structures, a uniform wall thickness is used, which is only thickened in certain areas. For cuboid or prism-shaped structures, the base wall, to which the guide system and, if applicable, a drive are connected, is usually constructed with a wall thickness equal to or greater than the wall thickness in the side walls. The wall thickness of the top wall is kept similar to that of the side walls. According to the state of the art, there is no significant change in the wall thickness within the cross-section, apart from local deviations such as ribs for reinforcement (DE10 2011 108 982 A1, DE10 2013 112 834 A1 DE10 2012 212 213 A1), thickenings for connecting a guide system (DE10 2011 108 982 A1, DE10 2013 112 834 A1, DE10 2012 212 213 A1, DE 10 2007 015 152 A1), changes for the integration of other components or openings for assembly work.

[0005] The underlying topic is illustrated below using a simplified example: Fig. 1 of the prior art shows a bending of a carriage body 2 caused by a force F on the functional unit 1 (shown in Fig. 1 as an arrow with the designation F for force). The position of the carriage body 2 is determined by its connection to a support 9 by means of a guide system consisting, on the one hand, of rails 5 and, on the other hand, of runners 6, 8, which are movable parallel to the rails and elastically connected to them perpendicular to the rails. The support 9 is usually a second carriage, which in turn is connected to a third, so that movements in space are possible. The carriage body 2 is essentially connected via the runners 6, 8. Under the effect of force F, a buckling zone is created in the carriage body. This is particularly pronounced in an area near the end faces 7 of those runners 6 which are the closest to the functional unit 1. The height of the carriage body is constant, although the bending loads vary greatly.

[0006] Most of the slide bodies 2 are connected to a support 9 on one side in the area of ​​runners 6, 8, which are fastened near the side walls. The greatest deformations occur when the runners 6, 8 are located near the rear end 4 of the slide body 2. Forces caused by interaction with workpieces are impressed via the functional unit 1 at the front end 3 of the slide body 2, approximately centrally. The force flows run from the functional unit 1 to the runners 6, 8. This results in stresses that vary greatly across the slide body. State-of-the-art slide bodies are only imperfectly adapted to these stress distributions. Therefore, the mass of the slide body is not optimally used to reduce important deformations and is greater than necessary. Problem

[0007] When functional units are moved along paths in space using slide systems, variable forces act due to accelerations and interactions between the functional unit and workpieces. These lead to deformations, particularly of the slide body of the slide to which the functional unit is directly connected. Some of these deformations, together with the weight of the slide, limit the speeds at which the functional unit can be moved along paths with large curvatures without exceeding specified deviations from an ideal curve. The extent of the relevant deformations and the total mass of the slide must be reduced. Proposed solution

[0008] The carriage is adapted to the strong differences in the loads acting in different areas by large changes in the outer contour and wall thickness of its carriage body, as described in the claims. Detailed description of the invention

[0009] Developing good slide body shapes for an application is a very difficult process, as fields of deformation vectors must be optimized and many different influences and variables must be considered. To facilitate understanding of the claims, only a few individual aspects can be illustrated with highly simplified examples.

[0010] Embodiments of the present invention are described below with reference to the accompanying figures. Identical or similar elements in the figures may be designated by the same reference numerals. However, the present invention is not limited to the embodiments and their features described below, but encompasses all possible embodiments that correspond to the independent claims. Reference is made to the figures in the claims solely to clarify the content using an example. However, the scope of the claims arises solely from the text and is not limited to the examples referred to for clarification.

[0011] As shown above, slides to which a functional unit is directly connected exhibit the greatest deformation under certain loads in the area of ​​a buckling zone. Since the slides are essentially held by the runners that are connected near the side walls, these slide areas make the greatest contribution to stability. Fig. 2 to 6, 10, 12 and 13 show examples of carriages according to the invention with carriage bodies 10, 27, 38, in which the rails 13 are attached to the side walls 18, 28, and 39 / 40 and the runners are attached to the carrier 17. The Fig. Figures 7 to 9 and 11 show an example in which the slides 14, 16 are attached to the carriage body 21 and the rails 13 to the support 24. Milling machine carriages were chosen as examples. The functional unit 1 here is a motor spindle that drives a tool. The front area of ​​the carriage and the carriage body is the area facing the functional unit. It is shown in the Fig. 2, Fig. 7, Fig. 10 and Fig. 11 shown below. In the area of ​​the end faces of the end walls of the slide bodies 11, 22, 31 and 43, the heights, i.e. the maximum distance of the outer contour of the slide bodies from the rails, are selected to be just sufficient to connect the spindle with good rigidity. With increasing distance from the end faces, the heights are increased until they reach a maximum in an area close to the slide end faces 15 of the front slides 14. Very large bending loads occur here when forces act on the spindle perpendicular to its axis in the plane of the drawing. The height of the slide bodies is considerably greater in this area than in prior art designs in order to significantly reduce bending. In the rear area of ​​the slide bodies, the bending loads are considerably smaller and the height of the slide bodies is greatly reduced in order to save weight.Weight can always be saved cost-effectively when the mass of the sled body decreases more than the relevant deformations increase.

[0012] An advantageous design of the front carriage area for embodiments in which the rails are directly connected to the carriage body is shown in the Fig. 2 , Fig. 4 and Fig. 5. The outer surfaces of the side walls have a greater distance at the transition to the rails than the outer surfaces of the rails Fig. 4, Fig. 5. With increasing distance from the rails, the outer surfaces of the side walls are shifted inward toward the functional unit to save weight. It is advantageous to use wall curves in some areas whose centers of curvature lie outside the carriage body in a spatial area that does not contain the carriage body. Such a curvature is also advantageous for the top wall and, in the side view, Fig. 2 can be seen.

[0013] The Fig. Figures 7 to 9 and 11 show advantageous designs of the front carriage area for carriage bodies 21, to which the runners 14, 16 are directly connected. In this case, in addition to the height, the distance between the outer surfaces of the side walls in the area of ​​the front end face 22 can be significantly reduced to achieve a favorable weight saving.

[0014] In the embodiments, the lengths of the carriage bodies are selected so that the rear ends 12, 23 have just sufficient overlap with the runners Fig. 2, Fig. 4, Fig. 7, Fig. 8, Fig. 10, Fig. 11. This short design saves weight at a low cost.

[0015] Fig. 3 and Fig. 6 shows examples of advantageous wall thickness gradients. The sides 18 have the greatest wall thicknesses in the area of ​​the rails and decrease with increasing distance from the rails. Both the bottom wall 19 and the top wall 20 have significantly thinner wall thicknesses than the side walls.

[0016] Fig. 10 and Fig. 12 shows examples of cutouts 25, 36 in the floor walls 19, 32, which can be used to save weight. Examples of cutouts 26, 35 in the top walls 25, 33, which extend from the rear sides of the carriage bodies 23, 29, which can also be used to save weight, are shown. Fig. 11 and Fig. 12.

[0017] Fig. 12 shows a section through the center of an embodiment consisting of two side walls 28, between which a central part 30 is connected, to whose inner opening 34 the functional unit 1 is connected. Interfaces for the supply of electrical cables and media required for the functional unit, and for the connection of further components such as cable trays, are located on the side walls. A plate 37 with an opening arranged between the side walls is shown as a representative example. The construction from discrete individual parts results in changes in the manufacturing processes, which are advantageous in some applications. In particular, different materials can be used for different parts, and at least parts of a base wall can be formed directly by part of a drive system, such as a linear motor.

[0018] Fig.Figure 13 shows a welded embodiment in which the rails 13 are screwed to intermediate parts 39, which in turn are welded to the side walls 40. A molded part 41 containing the cover wall 42 is welded between the side walls 40. The functional unit is attached to its end wall 43. Alternatively, the interior can be designed by welding in suitable metal sheets. Advantages of the invention

[0019] For slides with a functional unit 1 directly connected to the slide body 10, 21, 27, 38, significant deformations caused by loads are reduced compared to state-of-the-art designs without increasing weight, or the weight is reduced more than the deformations increase. This leads to an improvement in the dynamic properties of the motion systems, allowing the functional units to be moved at higher speeds on paths with large curvatures without exceeding specified limits of deviation from an ideal curve. The advantages are particularly pronounced with large overhangs of slide bodies over the guide system, i.e., large distances between the functional unit 1 and the sliders 14, 16.

[0020] During accelerations transverse to the rails, the position changes of the functional unit are also smaller in the inventive designs because less mass is used in the end regions than in the central region. For example, for this reason, when the carriage is in a central position, the forces generated at its front end in the area of ​​the functional unit are lower. While the mass savings at the front end are offset by an increase in mass in the central region, this leads to significantly less significant deformations than corresponding mass contributions in the front region due to the smaller lever arm relative to the guide system.

Claims

[1] Sled for fast, high-precision movements of functional units (1) on strongly curved paths, comprising a sled body (10, 21, 27, 38) designed as a hollow body and consisting of side walls (18, 28, 40) and bottom wall (19, 32) as well as top wall (20, 25, 33, 42) and end wall (11, 22, 31, 43) and which is connected to a support (17, 24) via a guide system consisting of rails (13) and runners (14, 16), wherein at least one rail or two runners are arranged at each of the two outer ends of the bottom wall in the areas of the overlap of the bottom wall with the side walls, characterized by , that in the majority of the sled body in cross-sections perpendicular to the rails (13) the wall thickness of the bottom wall (19, 32) averaged over the cross-section is less than 70% of the wall thickness of the side walls (18, 28, 40) averaged over the cross-section. [2] A carriage for fast, high-precision movements of functional units (1) on strongly curved paths, comprising a carriage body (10, 21, 27, 38) designed as a hollow body and consisting of side walls (18, 28, 40) and bottom wall (19, 32) as well as top wall (20, 25, 33, 42) and end wall (11, 22, 31, 43) and which is connected to a support (17, 24) via a guide system consisting of rails (13) and runners (14, 16), wherein at least one rail or two runners are arranged at each of the two outer ends of the bottom wall in the areas of the overlap of the bottom wall with the side walls, characterized by, that in the central area of ​​the sled body between the end wall, in whose area the functional unit (1) is attached, and the rear end of the sled body (12, 23, 29), the outer outlines of cross-sections through the sled body perpendicular to the rails (13) are significantly larger than in the area of ​​the end wall and the heights of the side walls reach maximum values ​​of 120 to 300% of their height at the end wall and characterized by , that at the rear end of the sled body (12, 23, 29) the outer outlines of cross-sections through the sled body perpendicular to the rails (13) are significantly smaller than in the central area. [3] Sled according to at least one of claims 1 or 2, characterized by , that the bottom wall (19, 32) has one or more openings (25, 36) whose total open length is 30 to 90% of the length of the sled body and whose greatest width is 60 to 100% of that of the bottom wall. [4] Sled according to at least one of claims 1 to 3, characterized by , that at least one of the three walls, bottom wall (19, 32), top wall (20, 25, 33, 42) or end wall (11, 22, 31, 43), is attached as a separate part to the side walls (18, 28, 40). [5] Sled according to at least one of claims 1 to 4, characterized by , that at least part of the floor wall (19, 32) consists directly of at least one part of a drive system. [6] Sled according to at least one of claims 1 to 5, characterized by , that at least over part of the front half of the sled body the wall thicknesses of the side walls (18, 28, 40) decrease over part of their height with increasing distance from the bottom wall (19, 32). [7] Sled according to at least one of claims 1 to 6, characterized by , that at least over part of the front half of the sled body the wall thicknesses of the side walls (18) increase in the transition to the top wall (20). [8] Sled according to at least one of claims 1 to 7, characterized by , that the rails (13) are connected to the side walls of the sled body (18, 40) directly or via an intermediate part (39) and that the outer surfaces of the side walls (18, 40) in the front area of ​​the sled body have a decreasing distance in cross-sections perpendicular to the rails (13) with increasing distance from the rails. [9] Sled according to at least one of claims 1 to 7, characterized by , that the runners (14, 16) are connected directly or via an intermediate part to the side walls of the slide body (21) and the maxima of the heights of the side walls are located near the end faces (15) of the runners (14) that face the functional unit. [10] Slide according to at least one of claims 1 to 7 and 9, characterized by, that the runners (14, 16) are attached directly or via an intermediate part (39) to the side walls of the sled body (21) and that the distances of the side walls increase with decreasing distance from the end face of the end wall of the sled body (22) in at least a part of the length of the sled body. [11] Sled according to at least one of claims 1 to 10, characterized by , that at least over part of the front area of ​​the slide body, in which the functional unit (1) is attached to the slide body (10, 21, 27, 38), the wall thickness of the top wall (20, 25, 33, 42) at the transition to the side walls (18, 28, 40) is significantly greater than in the middle between them. [12] Slide according to at least one of claims 1 to 11, characterized by, that at least in a part of the front area of ​​the sled body at least one outer surface of the side walls (18) or the top wall (20, 25, 33, 42) has a center of curvature which is on the side of the outer surface which is away from the sled body and does not contain the sled body. [13] Sled according to at least one of claims 1 to 12, characterized by , that in cross-sections perpendicular to the rails in the middle and rear area of ​​the sled body the wall thickness of the top wall (20, 25, 33, 42) averaged over the cross-section is less than 50% of the wall thickness of the side walls (18, 28, 40) averaged over the cross-section. [14] Slide according to at least one of claims 1 to 13, characterized by, that the cover wall (20, 25, 33, 42) of the slide body (10, 21, 27, 38) has one or more openings (26, 35) whose total open length is 30 to 70% of the length of the slide body (10, 21, 27, 38) and whose maximum width is 50 to 100% of the width of the cover wall. [15] Slide according to at least one of claims 1 to 14, characterized by , that a separate part (30, 41) is attached between the side walls (28, 40), which includes the bottom wall (32) and / or the top wall (33, 42) and to which the functional unit (1) is attached.

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