Guidance system
The guiding system achieves precision positioning with reduced gaps and forces, enhanced rigidity, and lower manufacturing costs by using magnetic forces to minimize gaps and restrict degrees of freedom.
Patent Information
- Application Number
- JP2024208268
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-12-19
- Filing Date
- 2024-11-29
- Publication Date
- 2025-07-01
AI Technical Summary
Existing guiding systems are not suitable for precision positioning applications, lack rigidity, require high displacement forces, are affected by operating temperature, and have high manufacturing costs.
A guiding system with a main and auxiliary guiding axis, using rolling element guiding devices to restrict four degrees of freedom and magnetic forces to minimize gaps, ensuring high precision and rigidity while reducing displacement forces and temperature dependence.
Enables precision positioning with minimal gaps, lower displacement forces, and reduced manufacturing costs, independent of temperature fluctuations.
Smart Images
Figure 2025097925000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a guiding system for guiding the displacement of a movable element relative to a fixed element, for example, a system for guiding the displacement of a carriage (or trolley) relative to a frame. In particular, the present invention relates to a guiding system for high-precision positioning applications, that is, applications where the positioning accuracy is 50 μm or less, particularly 10 μm or less, for example 1 μm or less. More specifically, the present invention relates to a guiding system that uses magnetic force to enable guidance with little or no clearance (or play).
Background Art
[0002] Guiding systems for guiding the displacement of a movable element relative to a fixed element, for example, and in a non-limiting manner, the displacement of a trolley relative to a frame, are known.
[0003] A plurality of known guiding systems - a linear actuator, and - a fixed element having one single guiding axis, and - a movable element (for example, along the z-axis line) arranged to be displaced (translated) by the linear actuator relative to the fixed element, which cooperates with the main guiding axis and is arranged to prevent five degrees of freedom of the movable element are provided.
[0004] The five degrees of freedom are - translation along a second axis of the movable element, for example translation along the x-axis line, - translation along a third axis of the movable element, for example translation along the y-axis line, - rotation about the second axis (x) of the movable element, - rotation about the third axis (y) of the movable element, - rotation about the first axis (z) of the movable element, respectively.
[0005] These known systems are not suitable for precision positioning applications. Furthermore, they lack rigidity. Finally, a large displacement force is required to move the movable element, and its accuracy often depends on the operating temperature due to the possibility of thermal expansion. Known guiding systems can also be costly to manufacture. Summary of the Invention Problems to be Solved by the Invention
[0006] An object of the present invention is to provide a guiding system that overcomes the drawbacks and limitations of the prior art.
[0007] Another object of the present invention is to provide a guiding system that is suitable for precision positioning applications.
[0008] Another object of the present invention is to provide a guiding system that is more rigid than known guiding systems.
[0009] Another object of the present invention is to provide a guiding system that requires a lower displacement force than that required by known guiding systems.
[0010] Another object of the present invention is to provide a guiding system that is less dependent on the operating temperature than known guiding systems.
[0011] Another object of the present invention is to provide a guiding system that has a lower manufacturing cost than known guiding systems.
[0012] Another object of the present invention is to provide a guiding system that can be used as an alternative to known guiding systems. Means for Solving the Problems
[0013] According to the present invention, these objects are achieved by the subject matter of the appended claims, in particular by the guiding system according to claim 1. On the other hand, the dependent claims alternatively or preferably relate to multiple embodiments of the present invention.
[0014] The guiding system for guiding the displacement of a movable element relative to a fixed element according to the present invention is - a linear actuator and includes - the fixed element has - a main guiding axis and - an auxiliary guiding axis, - the movable element is arranged to be displaced along a first axis by a linear actuator relative to the fixed element, and the movable element is - a first rolling element guiding device that cooperates with the main guiding axis and is arranged to prevent four degrees of freedom of the movable element, the four degrees of freedom including translation along a second axis (x), translation along a third axis (y), rotation about the second axis (x), and rotation about the third axis (y), the first rolling element guiding device - a second rolling element guiding device that cooperates with the auxiliary guiding axis and is arranged to prevent rotation of the movable element about a third axis (z). and includes
[0015] In a preferred embodiment, the first axis, the second axis, and the third axis are axes of a three-dimensional Cartesian coordinate system.
[0016] In this context, the expression "guiding axis" means a physical axis or rail.
[0017] In this context, the expression "rolling element guiding device" means a device including rolling elements to facilitate relative movement.
[0018] The rolling element guiding device may include (at least) a first element and (at least) a second element. In this case, the rolling elements are held between the first element and the second element to facilitate relative movement of the first element relative to the second element or vice versa.
[0019] In this context, the expression "rolling object" refers to any object that rolls, for example, but not limited to, balls, rollers (e.g., cylindrical rollers, conical rollers, etc.), needles, etc.
[0020] A rolling bearing or ball bearing is an example of a rolling element guiding device. Generally, it includes (at least) one outer ring (the first element), (at least) one inner ring (the second element, which is generally composed of two fixed parts), and rolling elements held between the outer ring and the inner ring. In some cases, a cage may be used to ensure the space for the rolling elements between the rings. In addition to ensuring the space for the rolling elements, the cage can also provide a function as a fastener, for example, in a non-limiting way.
[0021] The number of contact points between the rolling element and the ring (when the rolling element is a ball, for example), or the number of contact lines between the rolling element and the ring (when the rolling element is a roller, for example) may vary depending on the type of bearing.
[0022] The surface on which the rolling element rolls is generally referred to as the "raceway". This supports the load (axial and / or radial) applied to the bearing.
[0023] An example of a rolling element guiding device is a linear bearing. Generally, it includes a sleeve (the first element), a shaft (the second element), and rolling elements held between the sleeve and the shaft. The linear bearing may include a cage for holding and circulating the rolling elements. In this case, the cage does not act as a separator for the rolling elements. There is also a structure in which the rolling elements are inserted into the cage and the cage functions as a separator for the rolling elements. In this case, there is no circulation of the rolling elements.
[0024] Generally, linear bearings with rolling elements have two main types: recirculating track bearings (which do not limit the stroke length) and ball bushings (comprising inner and outer bushings and a ball cage). This type is easy to manufacture, and since the balls do not recirculate, smoother movement is achieved. In fact, the balls are always under load, but in the recirculating type, the balls change between a loaded state and an unloaded state. This can cause errors that can be measured on the micrometer scale. The drawback of this type is that the stroke is limited.
[0025] In this context, the expression "a guiding device that cooperates with a guiding shaft" means that the guiding device (at least partially) is located (at least partially) on or around the guiding shaft.
[0026] In the present invention, there is a gap between one or both of the main guiding shaft and the first rolling element guiding device and between the secondary guiding shaft and the second rolling element guiding device.
[0027] In the present invention, the fixed element or the movable element comprises a first magnet, and the movable element or the fixed element respectively comprises one or both of a ferromagnetic support and a second magnet. The first magnet and one or both of the ferromagnetic support and the second magnet are arranged to generate a magnetic force so as to reduce or avoid this gap, thereby enabling a guide with little or no gap.
[0028] The first magnet and the ferromagnetic support, The first magnet and the second magnet One or both of them are separated by a void. In one embodiment, the length of the void (i.e., the dimension along the y-axis line) depends on the application of the guiding system described in the claims.
[0029] The first magnet and one or both of the ferromagnetic support and the second magnet are on one or both of the main guiding shaft and the secondary guiding shaft.
[0030] In one embodiment, one or both of the first magnet and the second magnet are permanent magnets.
[0031] In one embodiment, the gap between the main guide shaft and the first rolling element guide device is minimized on the main guide shaft (where the rolling elements are preferably arranged at ±45° with respect to the axis perpendicular to the main base of the guide system), and the gap between the sub-guide shaft and the second rolling element guide device is minimized on the sub-guide shaft (where the rolling elements are preferably arranged at 0° with respect to the axis perpendicular to the main base of the guide system). Thereby, it is ensured that only one row of effective rolling elements is present on the sub-guide shaft.
[0032] In a preferred embodiment, if there are gaps between the main guide shaft and the first rolling element guide device and between the sub-guide shaft and the second rolling element guide device, a first magnet and a corresponding ferromagnetic support, or a second magnet are provided for each guide shaft. Therefore, the main guide shaft is provided with a first magnet and one or both of the corresponding ferromagnetic support and the second magnet, and the sub-guide shaft is provided with a first magnet and one or both of the corresponding ferromagnetic support and the second magnet. In embodiments where there are gaps in both shafts, two gap adjustment devices are required, but there is an advantage that the allowable error of the shaft diameter can be increased.
[0033] The guide system described in the claims is suitable for precision positioning applications because it enables a guide with little or no gap, and in this regard, the present invention is superior to known state-of-the-art technologies.
[0034] Since the guide system described in the claims has two axes, it has higher rigidity than known guide systems.
[0035] The guide system described in the claims is based on the fact that there is a gap in one or both of the spaces between the main guide shaft and the first rolling element guide device and between the sub-guide shaft and the second rolling element guide device, and the use of magnetic forces arranged to reduce or avoid this gap. Thereby, a guide with little or no gap becomes possible. As a result, the displacement force required to move the movable elements of the guide system described in the claims is smaller than the displacement force required for known guide systems.
[0036] Furthermore, the guidance provided by the guidance system according to the present invention is independent of the operating temperature and is thus not subject to the adverse effects of thermal expansion.
[0037] Furthermore, the guidance system according to the present invention allows for a wide tolerance in the dimensions of the guide shafts, enabling either or both of their ease of selection and reduction of manufacturing costs.
[0038] In one embodiment, the gap is located either or both between the distal portion of the main guide shaft and the distal portion of the first rolling element guide device, and between the distal portion of the secondary guide shaft and the distal portion of the second rolling element guide device. This gap is hereinafter referred to as the "first gap".
[0039] In this context, the expression "distal portion" refers to the portion that is furthest from any of the first magnet, the ferromagnetic support, and the second magnet.
[0040] In this embodiment, the first magnet and either or both of the ferromagnetic support and the second magnet are arranged to generate a magnetic force so as to reduce or avoid this first gap. By this reduction or invalidation (of the first gap), a second gap is formed either or both between the proximal portion of the main guide shaft and the proximal portion of the first rolling element guide device and between the proximal portion of the secondary guide shaft and the proximal portion of the second rolling element guide device. Thereby, contact either or both between the proximal portion of the main guide shaft and the proximal portion of the first rolling element guide device and between the proximal portion of the second guide shaft and the proximal portion of the second rolling element guide device is eliminated. However, this second gap has little effect on the accuracy of the guidance system according to the present invention.
[0041] In this context, the expression "proximal portion" refers to the portion that is closest to any of the first magnet, the ferromagnetic support, and the second magnet. In a preferred embodiment, the proximal portion faces the distal portion.
[0042] In one embodiment, the main guide shaft is parallel to the secondary guide shaft.
[0043] In one embodiment, the main guide shaft is longer than the secondary guide shaft.
[0044] In one embodiment, the fixed element is a frame (or chassis), and the movable element is a trolley.
[0045] In one embodiment, the movable element is arranged to hold a device, such as an optical objective lens.
[0046] In one embodiment, the guiding system comprises two spaced-apart first rolling-element guiding devices that cooperate with a main guiding axis.
[0047] In one embodiment, one or both of the first rolling-element guiding device and the second rolling-element guiding device are (rolling or linear) bearings, such as an N-point contact bearing, where N is a positive integer. In one embodiment, N = 4.
[0048] In one embodiment, the first rolling-element guiding device is offset from the second rolling-element guiding device by, for example, 45° (with a tolerance of, for example, ±10°).
[0049] In one embodiment, the second rolling-element guiding device is a track of rolling elements along a secondary guiding axis.
[0050] In one embodiment, the linear actuator comprises at least one of a lead screw nut system, a ball screw, a cam, a connecting rod, a belt, a rack, and the like.
[0051] In one embodiment, the guiding system comprises means for determining a position along a first axis (z-axis), and the means is arranged for one or both of applying a preload on the first axis and reducing or eliminating a gap along the first axis.
[0052] In one embodiment, the means for determining a position along the first axis (z-axis) comprises one or more springs, for example one spring per guiding axis.
[0053] In one embodiment, the means for determining a position along the first axis (z-axis) comprises a third magnet and a third ferromagnetic support.
[0054] Representative embodiments of the present invention are disclosed in the description thereof and are shown in the following drawings.
Brief Description of the Drawings
[0055]
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DETAILED DESCRIPTION OF THE INVENTION
[0056] In the following description, for the sake of simplicity, reference is made to the magnetic force between the (first) magnet and the ferromagnetic support. However, it should be understood that the present invention is not limited to such a magnetic force and includes (complementarily or alternatively) the magnetic force between the first magnet and the second magnet.
[0057] FIG. 1 shows a schematic cross-sectional view of an embodiment of a guiding system 100 according to the present invention.
[0058] The guiding system 100 is arranged to guide the displacement of the movable element 13 relative to the fixed element 14, and the guiding system 100 - a linear actuator (for example, may include a cam 6 as visible in FIG. 3), and - a fixed element 14 and is provided with. The fixed element 14 - a main guiding shaft 5, and - a sub-guiding shaft 4 and is provided with. The guiding system 100 - The movable element 13 includes a movable element 13 arranged to be displaced along a first axis, for example, the z-axis line (see FIG. 3), by a linear actuator relative to the fixed element 14. The movable element 13 - A first rolling element guiding device 50 arranged to cooperate with the main guiding shaft 5 to block four degrees of freedom of the movable element, and - Having a secondary guide shaft 4 and being arranged to prevent rotation of a movable element centered on the third axis line (z), a second rolling element guide device 40 is provided.
[0059] The four degrees of freedom include translation along the second axis line (x), translation along the third axis line (y), rotation centered on the second axis line (x), and rotation centered on the third axis line (y).
[0060] In this embodiment, the fixed element 14 is a frame (or chassis), and the movable element 13 is a trolley arranged to hold a device, such as an optical objective lens. In the illustrated embodiment, it includes a portion having a receptacle 130 arranged to hold a device as an optical objective lens.
[0061] In this context, the expression "guide shaft" refers to a physical shaft or rail. Those guide shafts can be particularly seen in FIG. 3.
[0062] In one embodiment, the main guide shaft 5 is parallel to the secondary guide shaft 4, as shown, for example, in FIG. 3.
[0063] In one embodiment, the main guide shaft 5 is longer than the secondary guide shaft, as can be seen, for example, in FIG. 3.
[0064] In this context, the expression "rolling element guide device" refers to a device provided with rolling elements to facilitate relative movement.
[0065] In this context, the expression "rolling element" indicates any object that rolls, for example, by way of non-limiting examples, balls, rollers (such as cylindrical rollers, tapered rollers, etc.), needles, etc.
[0066] As an example of a rolling element guiding device, a linear bearing (linear motion bearing) can be cited (non-limiting example). This generally includes a sleeve (first element), a shaft (second element), and rolling elements held between the sleeve and the shaft. The linear bearing may include a cage that holds and recirculates the rolling elements. In this case, the cage does not function as a separating device for the rolling elements.
[0067] In one embodiment of FIG. 1, there is a first linear bearing 50 including a sleeve 51, a shaft (which is a part of the main shaft 5), and rolling elements 500 held between the sleeve and this part of the main shaft 5.
[0068] In the embodiment of FIG. 2, there is a second linear bearing 40 including a sleeve 41, a shaft (a part of the auxiliary shaft 4), and rolling elements 400 held between the sleeve and this part of the auxiliary shaft 4.
[0069] In one embodiment, one or both of the first rolling element guiding device 50 and the second rolling element guiding device 40 is an N-point contact bearing, where N is a positive integer. In one embodiment, N = 4. However, this number is not limiting, and rolling element guiding devices with different numbers of contact points may be used as well, such as N = 3, N = 7, etc. Further, the number of contact points of the first rolling element guiding device 50 may be different from the number of contact points of the second rolling element guiding device 40.
[0070] In an embodiment not described in the claims, the fixed element includes two rolling element guiding devices, and the movable element includes two guiding shafts. However, this embodiment has the disadvantage that the guiding shafts protrude from the fixed element and occupy more space than the claimed guiding system.
[0071] Referring to FIG. 1, according to the present invention, there are gaps (not shown) between the main guiding shaft 5 and the first rolling element guiding device 50, and between the auxiliary guiding shaft 4 and the second rolling element guiding device 400.
[0072] According to the present invention, the fixed element or the movable element includes at least magnets 20 (two in one embodiment of FIG. 1), and the movable element and the fixed element each include at least ferromagnetic supports 15, 16 (two in one embodiment of FIG. 1). In particular, for each guide shaft 4, 5, there is one magnet 20 and one ferromagnetic support 15, 16 respectively.
[0073] In one embodiment of FIG. 1, each magnet is cylindrical and is a magnetic disk.
[0074] In the present invention, the magnet(s) 20 and the ferromagnetic support(s) 15, 20 are arranged to generate magnetic force so as to reduce or avoid this gap, thereby enabling a guide with almost no or no gap.
[0075] Regarding matters well-known in the art, the present invention provides the advantage that the guide system 100 described in the claims is suitable for precision positioning applications in order to enable a guide with almost no or no gap.
[0076] Since the guide system described in the claims includes two shafts 4, 5, it has higher rigidity than known guide systems.
[0077] The guide system described in the claims is based on the fact that there is a gap in one or both of the main guide shaft 5 and the first rolling element guide device 50, and between the auxiliary guide shaft 4 and the second rolling element guide device 40, and using magnetic force arranged to reduce or avoid this gap, thereby enabling a guide with almost no or no gap. Thereby, the displacement force required for the guide system 100 described in the claims is lower than the displacement force required for known guide systems. In particular, the displacement force required for the guide system 100 described in the claims is about one-tenth (1 / 10) lower than the displacement force required for known guide systems.
[0078] Furthermore, the guide provided by the guide system 100 described in the claims is not affected by the influence of thermal expansion and thus does not depend on the operating temperature.
[0079] In one embodiment, the gap is in one or both of the space between the distal portion of the main guide shaft 5 and the distal portion of the first rolling element guide device 50, and the space between the distal portion of the sub-guide shaft 4 and the distal portion of the second rolling element guide device 40. This gap is hereinafter referred to as the "first gap".
[0080] In this context, the expression "distal portion" means the portion that is furthest from the magnets 20 and the ferromagnetic supports 15, 16.
[0081] FIG. 2 shows details of the sub-guide shaft (left side) and the main guide shaft (right side) of the guide system of FIG. 1.
[0082] In one embodiment of FIG. 2, the distal portion of the main guide shaft 5 is the upper part of the main guide shaft 5, and the distal portion of the first rolling element guide device 50 is the upper part of the first rolling element guide device 50. Similar considerations apply to the sub-guide shaft 4 and the second rolling element guide device 40.
[0083] The magnets 20 and the ferromagnetic supports 15, 16 are separated by an air gap d', and are arranged to generate a magnetic force so as to reduce or avoid this first gap. This magnetic force is the adhesive force F shown in FIG. 2 A as shown.
[0084] The movable element 13 then receives two forces, the weight acting at the center of gravity (CG, illustrated in FIG. 4 for example) and the adhesive force F A The reaction force on the support acts on the bearing raceway at an angle according to the arrangement of the raceways. The movable element 13, and then the sleeves 41, 51 of the guide devices 40, 50, are pulled downward (i.e., towards the magnet or the ferromagnetic support) by the adhesive force F A As a result of this displacement, the first gap is reduced or avoided. Due to this displacement, a second gap (not shown) is generated in one or both of the space between the proximal portion of the main guide shaft 5 and the proximal portion of the first rolling element guide device 50, and the space between the proximal portion of the sub-guide shaft 4 and the proximal portion of the second rolling element guide device 40. However, this second gap has little effect on the accuracy of the guide system 100 according to the present invention.
[0085] In this context, the expression "proximal portion" refers to the portion closest to the magnet and the ferromagnetic support. In a preferred embodiment, the proximal portion faces the distal portion.
[0086] In the embodiment of FIG. 2, the proximal portion of the main guide shaft 5 is the lower part of the main guide shaft 5, and the proximal portion of the first rolling element guide device 50 is the lower part of the first rolling element guide device 50. The same consideration applies to the sub-guide shaft 4 and the second rolling element guide device 40.
[0087] In other words, the guide system according to the present invention intentionally introduces a first gap and uses magnetic force to reduce or eliminate it.
[0088] In one embodiment of FIG. 2, each rolling ball guide device 40 includes at least one loaded ball 400, 500 (black), at least two unloaded balls 400', 500' (gray), and some of which are circulating balls 400'', 500'' (white).
[0089] In the embodiment of FIG. 2, the rolling element guide devices 40, 50 are offset so as to efficiently disperse the support portions of the movable element 13 on the shafts 4, 5. In a preferred embodiment, as shown in FIG. 14, the rolling element guide devices 40, 50 are offset by 45°. This is because there are four contact points. The angle of offset depends on the number of contact points. For example, when there are three contact points, it is 60°, and when there are five contact points, it is 36°.
[0090] In one embodiment, the number of contact points is three or four. This is because the smaller this number, the larger the horizontal component of the downward force and the more stable the guidance. In one embodiment, there are three rows of contacting rolling elements, in particular, two rows arranged at ±45° with respect to the vertical axis of the main base of the guide system on the main guide shaft and one row arranged at 0° with respect to the vertical axis of the main base of the guide system on the sub-guide shaft.
[0091] In one embodiment, the first rolling element guiding device 50 is arranged to guide at a distance of 1.5 times or more the diameter of the main shaft 5. In the case of a configuration where the center of gravity CG of the movable element 13 is displaced by a distance d from the guide plane GP, as shown in FIG. 4, for high-speed positioning with a high acceleration a, for example, an acceleration of 2G, it is necessary that the positioning be accurate, for example, within a time interval of less than 10 milliseconds, and preferably, as shown in FIG. 4, the main guide shaft 5 preferably has two (or more) first rolling element guiding devices 50, 50' spaced apart by a distance b.
[0092] In this context, the auxiliary guide shaft 5 may also be referred to as an anti-rotation shaft in order to fix the degree of freedom of θz. The remaining degree of freedom is translation along the z-axis line, which can be controlled by transmission elements such as a screw nut system, a ball screw, a cam, a connecting rod, a belt, and a rack. This transmission element is generally connected to an actuator (as a motor) to form a linear actuator.
[0093] As the distance (distance c in FIG. 3) between the two shafts 4, 5 increases, the angular variation dθx caused by one or both of the alignment error (parallelism, conicity of the shaft, etc.) and the surface error (roughness) decreases.
[0094] As a non-limiting example of the calculation of the required adhesive force FA, having a cylindrical magnet 20 made of neodymium N45 with a diameter of 6 mm and a height of 2 mm, a holding force of 7.4 N, and a pure iron plate and an air gap d' of 0.2 mm, the adhesive force F A is 4.8 N.
[0095] When there are two linear bearings 50, 50' on the main shaft 5, as shown in FIG. 4, one magnet 20 may be used for each bearing. In this dimensional example, the value obtained by multiplying the distance b between the two linear bearings 50, 50' on the main shaft by the adhesive force F A should preferably be 1.5 times or more the force moment equal to the product of the mass of the movable element 13, the maximum acceleration, and the distance d between the guide plane GP and the center of gravity CG of the movable element 13 (see FIG. 4).
[0096] When the distance d is 4.5 mm, the distance b is 23 mm, and the mass m is 50 g, the maximum allowable acceleration is equal to 327 mm / s2, which is derived from Equations (1) to (6) as shown in Equation (7) below.
Number
[0097] As another example, when the acceleration is 1 m / s 2 , the mass is 30 g, the distance d is 10 mm, and the distance b is 30 mm, the adhesive force F A is given by the following Equations (8) to (10). Equation (8) is derived from Equation (4).
Number
[0098] Figures 5 to 14 show different views of an embodiment of the guiding system 100 according to the present invention. The arrangement and / or presence of some of the illustrated components, such as screws 21 to 26, 30, 32, nuts 31, 33, pins 27, 28, and gauge 19, are not necessarily essential, respectively.
[0099] In one embodiment, the guiding system 100 comprises means for determining a position along a first axis (z-axis). In one embodiment, the means for determining a position along the first axis (z-axis) comprises one or more springs, for example one spring for each guiding axis. Examples of these springs 18 are shown, for example, in Figure 6.
[0100] In one embodiment, the tension of each spring 18 can be adjusted, for example, by using a movable spring clip 12 at one end thereof.
[0101] These springs 18 allow the fixed linear actuator 6 (the cam in FIG. 3) to contact the spindle 2. However, there is a possibility that the contact force may not be constant along the axes 4 and 5. In addition, the cam 6 may wear, and there is a possibility that an excessive load may be applied to the motor. In a preferred embodiment, the preload is obtained by the magnetic force (adhesive force) between one or more magnets (not shown) and a ferromagnetic support (not shown). In particular, one magnet is within or on the linear actuator 6 or the spindle 2, and the ferromagnetic supports are within the spindle 2 or on the linear actuator 6, respectively. This embodiment has the advantage that a constant force can be applied along the axes 4 and 5. In addition, the cam 6 is less likely to wear, and the motor is less likely to be overloaded.
[0102] In one embodiment from FIGS. 5 to 14, there are a total of two ferromagnetic supports 15, 16, one for each of the axes 4, 5. In this embodiment, the dimensions and shapes of the ferromagnetic supports 15, 16 are different from each other.
[0103] The guiding system 100 may also include measuring means for measuring the displacement of the movable element 13, such as measuring means such as a PCB linear sensor 3 (supported by a PCB support 8 via a PCB board spacer 7 and a PCB spacer 9 shown in FIG. 6).
[0104] FIG. 15A shows a perspective view of a part of the guiding system 100 according to the present invention, which includes an embodiment of a secondary guiding axis. FIG. 15B shows a perspective view of some components of the guiding system of FIG. 15A. FIG. 16 shows a sectional view of a part of the guiding system of FIGS. 15A and 15B. In this embodiment, the second rolling element guiding device is a rolling element track 44 along the secondary guiding axis.
[0105] When the rolling element guiding device includes a plurality of contact points, that is, a plurality of tracks, only one track is used in the present invention. Therefore, in one embodiment, the second rolling element guiding device is replaced by a simple rolling element track 44.
[0106] The number of rolling elements 400 in the rolling element track 44 of FIG. 15B is not limited and varies depending on the application.
[0107] In this embodiment, a cage 44 may be used to separate the rolling elements 400. The guiding system 100 of this embodiment includes two substantially parallel ferromagnetic supports 16, 16', one of which is a fixed part (reference numeral 16 in FIG. 16) and the other is a movable part (reference numeral 16' in FIG. 16). The inner surfaces of each ferromagnetic support 16, 16', i.e., the surfaces facing the other ferromagnetic support 16, 16', are formed with a rolling element 400, for example, an adjusting surface 161, so as to have at least a point contact with the rolling element 400. Magnets 20, for example, magnets 20 polarized in the thickness direction of the system 100, are arranged with a gap d' therebetween by the respective ferromagnetic supports 16, 16' in the same manner as in the previous embodiment. In this embodiment, the guiding system 100 also includes fixing means 160.
[0108] FIG. 18 shows a sectional view of a partial embodiment of the guiding system 100 according to the present invention. FIG. 19 shows a perspective view of a part of the guiding system of FIG. 18.
[0109] In this embodiment, a cross roller or a ball rail is used as the guiding shafts 4, 5. In this embodiment, a preload can be applied via a radial screw (not shown) tightened with a torque determined in relation to a desired preload. However, these screws require high torque and generate non-uniform forces along the length of the shaft. In a preferred embodiment, the preload is obtained by the magnetic force (adhesive force) between one or more magnets 20 and the ferromagnetic supports 15, 16. This embodiment has the advantage that a constant force can be applied along the length of the shafts 4, 5.
[0110] In one embodiment of FIGS. 17 and 18, the system includes side ferromagnetic supports 15, 16 having an L-shaped section spaced from the track of each magnet 20 in the fixed element 13 by a gap d'.
Description of Reference Numerals
[0111] 1 Linear bearing 2 Main shaft 3 PCB linear sensor 4 Auxiliary guide shaft 5 Main guide shaft 6 Cam 7 PCB board spacer 8 PCB support 9 PCB spacer 10 Bearing fixing screw 11 Fixing screw clip 12 Movable screw clip 13 Movable element 14 Fixed element 15 Ferromagnetic support part 16 (Fixed) ferromagnetic support part 16’ (Movable part) ferromagnetic support part 17 Bearing 18 (Tensile) spring 19 Linear scale 20 Magnet (magnetic disc) 21 to 26 Screws 27 Pin 28 Pin 29 Insulating spacer 30 Screw 31 Nut 32 Screw 33 Nut 40 Second rolling element guiding device 41 Sleeve of the second rolling element guiding device 42 Cage 43 Cage stopper 44 Rolling element track 50, 50’ First rolling element guiding device 51 Sleeve of the first rolling element guiding device 100 Guiding system 130 Container 160 Fixing means 161 Adjusting surface 400, 500 Rolling elements 400’, 500’ Rolling elements 400’’, 500’’ Rolling elements b Distance between the first rolling element guiding devices c Distance between the two shafts 4 and 5 CG Center of gravity Distance from CG to GP d’ Gap GP Guide plane F A Adhesive force
Claims
1. A guide system (100) for guiding the displacement of a movable element (13) relative to a fixed element (14), said guide system (100) comprising: - Linear Actuators (6) Equipped with said fixing element (14) - the main guide shaft (5), a secondary guide shaft (4), said movable element (13) is arranged to be displaced along a first axis (z) by said linear actuator (6) relative to said fixed element (14), said movable element (13) being a first rolling element guiding device (50) arranged to cooperate with said main guiding shaft (5) and to block four degrees of freedom of said mobile element, said four degrees of freedom comprising a translation along a second axis (x), a translation along a third axis (y), a rotation about the second axis (x) and a rotation about the third axis (y); a second rolling element guide (40) arranged to cooperate with said secondary guide shaft (4) and to prevent rotation of the mobile element about the third axis (z); Equipped with In the guidance system (100), Between the main guide shaft (5) and the first rolling body guide device (50), and between the sub guide shaft (4) and the second rolling body guide device (40). There is a gap in one or both of The fixed element (14) or the movable element (13) comprises a first magnet (20), The movable element (13) or the fixed element (14) each comprises a ferromagnetic support (15, 16) and / or a second magnet, The first magnet (20) and the ferromagnetic support (15, 16) or the second magnet, respectively, are arranged to generate a magnetic force (FA) arranged to reduce or eliminate the gap, thereby enabling guiding with little or no gap at all, the guiding system (100).
2. The gap is between a distal portion of the main guide shaft (5) and a distal portion of the first rolling body guide device (50), and Between the distal portion of the secondary guide shaft (4) and the distal portion of the second rolling element guide device (40). The guidance system (100) of claim 1,
3. The gap exists between the main guide shaft (5) and the first rolling body guide device (50), and between the sub guide shaft (4) and the second rolling body guide device (40), The guidance system comprises: a first magnet and one or both of a corresponding ferromagnetic support and a corresponding second magnet in said main guide shaft; a first magnet, and at least one of a corresponding ferromagnetic support and a corresponding second magnet in the secondary guide shaft; The guidance system (100) of claim 1, comprising:
4. The guidance system (100) according to claim 1, wherein the main guidance axis (5) is parallel to the secondary guidance axis (4).
5. The guidance system (100) according to claim 1, wherein the main guide shaft (5) is longer than the secondary guide shaft (4).
6. The guiding system (100) of claim 1, wherein said guiding system comprises two spaced apart first rolling element guiding devices (50, 50') cooperating with said main guiding shaft.
7. The guiding system (100) of claim 1, wherein one or both of the first rolling element guiding device (50) and the second rolling element guiding device (40) are rolling or linear bearings, e.g., N-point contact bearings, where N is a positive integer.
8. The guidance system (100) of claim 1, wherein the first rolling element guiding device (50) is offset with respect to the second rolling element guiding device (40).
9. The guiding system (100) of claim 1, wherein the second rolling element guiding device (40) is a track (44) of rolling elements along the secondary guiding axis.
10. The guidance system (100) of claim 1, wherein said guidance system comprises a determining means for determining a position along said first axis (z).