Motion system of a coordinate measuring machine
By adopting an asymmetrical slider design on the guide rail of the coordinate measuring machine, torque and force balance are achieved, solving the problem of low stability of the guide rail structure and improving the stability and accuracy of the motion system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHOTEST TECH INC
- Filing Date
- 2023-02-23
- Publication Date
- 2026-05-29
AI Technical Summary
The existing coordinate measuring machine's guide rail structure has low stability and is prone to damage. In particular, it is difficult to achieve torque balance and force balance when suspended, resulting in unstable motion.
The slider design employs an asymmetrical layout, placing sliders in different areas of the guide rail. Multiple sliders apply forces in different directions to achieve torque and force balance. Air-bearing sliders are used to reduce friction and ensure stable sliding of the sliders on the guide rail.
This improves the structural stability of the guide rail and the rigidity of the motion system, reduces friction, ensures the stability and accuracy of the probe's movement, and extends the service life of the guide rail.
Smart Images
Figure CN116412734B_ABST
Abstract
Description
Technical Field
[0001] This disclosure generally relates to the field of intelligent manufacturing equipment industry, and specifically to a motion system for a coordinate measuring machine. Background Technology
[0002] A coordinate measuring machine (CMM) is an instrument capable of measuring geometric shapes, lengths, and circumferential divisions within a six-sided spatial area. It is also known as a coordinate measuring machine or a coordinate measuring machine bed. A CMM can also be defined as "an instrument with a detector that can move in three directions on three mutually perpendicular guide rails. This detector transmits signals in a contact or non-contact manner. The displacement measurement system of the three axes (such as an optical encoder) calculates the x, y, z coordinates and various functional measurements of the workpiece using a data processor or computer."
[0003] A coordinate measuring machine (CMM) includes a probe for measurement and a motion system for controlling the probe's movement. Structural improvements to CMMs mainly involve several aspects, such as improvements to the probe structure and the motion system. For example, Chinese patent CN109211171B discloses a gantry-type moving device and a three-dimensional measuring instrument, which uses multiple air bearings to mount two legs of the gantry-type moving body to a base. However, because each leg's air bearing can only provide force in a maximum of three directions, multiple air bearings must be installed on multiple legs simultaneously. Another example is Chinese patent CN213870762U, which discloses a closed guide rail structure for a CMM, including a granite guide rail and a sliding plate. The sliding plate is located on the outer side of the granite guide rail, and air bearings are installed on the four inner walls of the sliding plate, symmetrically circling the granite guide rail. Under the influence of gravity, the air float at the top of the granite guide rail will exert a large force on the granite guide rail. Since the air float is symmetrically arranged around the granite guide rail, an air float is also set at the bottom of the granite guide rail. It is impossible to use other structures to support the bottom of the granite guide rail (that is, the granite guide rail is in a suspended state). As a result, the stability of this structure is low, and the granite guide rail is prone to damage. Summary of the Invention
[0004] This disclosure was made in view of the above-mentioned state of the prior art, and its purpose is to provide a motion system for a coordinate measuring machine that improves the structural stability of the guide rail by placing the slider in different regions of the guide rail in an asymmetrical manner.
[0005] Therefore, this disclosure provides a motion system for a coordinate measuring machine (CMM), which is a motion system disposed on the CMM and controls the movement of the CMM's probe. The motion system includes a guide rail, a base having a groove and surrounding the guide rail through the groove, and a plurality of sliders disposed in the groove surrounding the guide rail and movable relative to the guide rail. The plurality of sliders includes a first slider for applying a first force to the base in a first direction, a second slider for applying a second force to the base in a second direction, a third slider for applying a third force to the base in a third direction, and a fourth slider for applying a fourth force to the base in a fourth direction. The slider has a first direction opposite to the third direction, a second direction opposite to the fourth direction, and the first direction orthogonal to the second direction. The guide rail includes a second plane opposite to the second slider and a fourth plane opposite to the fourth slider. The second plane is parallel to the fourth plane, and the fourth direction is perpendicular to the fourth plane. When the second plane is adjusted to a horizontal plane, the fourth direction is the direction of gravity. The guide rail includes a first guide rail area and a second guide rail area arranged sequentially along the first direction. The third slider and the second slider are disposed between the base and the first guide rail area, and the first slider and the fourth slider are disposed between the base and the second guide rail area.
[0006] In this configuration, since the bottom of the first guide rail area is not equipped with a fourth slider (i.e., it is not suspended), it exhibits high structural stability. Consequently, the guide rail remains stable even under the large force applied by the second slider. Furthermore, because the second slider is positioned between the base and the first guide rail area, and the fourth slider is positioned between the base and the second guide rail area, they are not symmetrical about the guide rail in the horizontal direction (i.e., the x-axis direction). When the base (or gantry structure) is subjected to the second force applied by the second slider and the fourth force applied by the fourth slider, it is difficult to achieve torque balance. Therefore, the third slider positioned between the base and the first guide rail area, and the first slider positioned between the base and the second guide rail area, can achieve torque balance through the first and third forces, thereby ensuring the stability of the base (or gantry structure) during movement.
[0007] Additionally, in the motion system of the coordinate measuring machine disclosed herein, the slider may optionally be an air-bearing slider. This allows the air-bearing slider to eject gas onto the guide rail, creating a gap between the slider and the guide rail, thereby reducing the friction between them and enabling the slider to slide stably on the guide rail.
[0008] Furthermore, in the motion system of the coordinate measuring machine disclosed herein, optionally, the guide rail includes a first plane opposite to the first slider and a third plane opposite to the third slider. In this case, the plane can effectively reduce the friction between the guide rail and the slider, while enabling the slider to maintain linear motion during sliding, thereby improving the stability of the base motion.
[0009] Furthermore, in the motion system of the coordinate measuring machine disclosed herein, optionally, the second slider is located at one end of the second plane near the third plane. In this case, the force exerted by the second slider on the guide rail can be concentrated at the end of the second plane near the third plane, further moving the point of application of the force exerted by the second slider on the guide rail to a region with the highest possible structural stability.
[0010] Additionally, in the motion system of the coordinate measuring machine disclosed herein, optionally, the third slider is located at one end of the third plane near the second plane. In this case, the depth of the second cutting groove can be minimized. Since the smaller the depth of the second cutting groove, the less part needs to be cut during processing, and the higher the rigidity of the guide rail.
[0011] Additionally, in the motion system of the coordinate measuring machine disclosed herein, optionally, the fourth slider is located at the end of the fourth plane closest to the first plane. In this case, the depth of the first cutting groove can be minimized. Since the smaller the depth of the first cutting groove, the less part needs to be cut during processing, and the higher the rigidity of the guide rail.
[0012] Furthermore, in the motion system of the coordinate measuring machine disclosed herein, optionally, the slider includes a sliding surface facing the guide rail, and the sliding surface of the second slider is larger than that of the first slider, the third slider, and the fourth slider. In this case, since the force applied and the reaction force received by the second slider are larger, increasing the sliding surface of the second slider can optimize the stress distribution and reduce the occurrence of adverse conditions due to stress concentration.
[0013] Furthermore, in the motion system of the coordinate measuring machine disclosed herein, optionally, the thickness of the first guide rail region is greater than the thickness of the second guide rail region along the fourth direction. In this case, the portion of the guide rail with a higher thickness along the fourth direction has higher structural stability when subjected to forces along the second or fourth direction. Simultaneously, it is more susceptible to the influence of gravity (i.e., forces pointing in the fourth direction) of the motion system, thus the first guide rail region can have higher structural stability or higher stiffness. Meanwhile, since the second guide rail region has a smaller thickness, a fourth slider can be provided at the bottom of the second guide rail region, thereby providing a force towards the base in the fourth direction, and thus preventing the base or right column (described later) from tipping over due to uneven force distribution.
[0014] Additionally, in the motion system of the coordinate measuring machine disclosed herein, optionally, a worktable for carrying a workpiece is included, with the first guide rail area disposed on one side of the worktable. In this case, the workpiece can be placed on the worktable, and the probe can be controlled using the motion system to measure the workpiece located on the worktable.
[0015] In addition, in the motion system of the coordinate measuring machine disclosed herein, optionally, a support structure is provided at the bottom of the first guide rail region. In this case, the support structure can be used to apply a force pointing in the second direction to the first guide rail region, thereby reducing the internal force between the first guide rail region and the worktable, thus reducing the deformation of the guide rail and the worktable, improving the accuracy and rigidity of the guide rail, and thereby improving the structural stability of the guide rail.
[0016] According to this disclosure, a motion system for a coordinate measuring machine can be provided that improves the structural stability of the guide rail by placing the slider in different regions of the guide rail in an asymmetrical manner. Attached Figure Description
[0017] Embodiments of this disclosure will now be explained in further detail with reference to the examples in the accompanying drawings, wherein:
[0018] Figure 1 This is a schematic diagram illustrating an application scenario of the coordinate measuring machine involved in the embodiments of this disclosure.
[0019] Figure 2 This is a front view showing a portion of the structure of the motion system according to an embodiment of the present disclosure.
[0020] Figure 3 This is a schematic diagram showing the structure of the guide rail and worktable according to the embodiments of this disclosure.
[0021] Figure 4This is a schematic diagram showing the connection structure of the guide rail, slider, and base according to the embodiments of this disclosure.
[0022] Figure 5 It shows Figure 4 A planar schematic diagram of the guide rail.
[0023] Figure 6 It shows Figure 4 A three-dimensional schematic diagram of the slider and the base.
[0024] Figure 7 This is a schematic diagram showing the connection structure of the guide rail, slider, and base involved in an embodiment where the slider is arranged in a symmetrical manner.
[0025] Figure 8 This disclosure illustrates Figure 7 Implementation methods and Figure 5 A schematic diagram showing the variations in the implementation method.
[0026] Figure 9 This is a schematic diagram showing the forces acting on the base according to an embodiment of the present disclosure. Detailed Implementation
[0027] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same components, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the components or the shapes of the components may differ from actual figures.
[0028] It should be noted that the terms "comprising" and "having" and any variations thereof in this disclosure, such as a process, method, system, product, or device that includes or has a series of steps or units, are not necessarily limited to those steps or units that are explicitly listed, but may include or have other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.
[0029] Figure 1 This is a schematic diagram illustrating an application scenario of the coordinate measuring machine 1 according to the embodiments of this disclosure. Figure 2 This is a front view showing a portion of the structure of the motion system according to an embodiment of the present disclosure.
[0030] Embodiments of this disclosure relate to a motion system for a coordinate measuring machine 1, which is a motion system disposed on the coordinate measuring machine 1 and controlling the movement of the probe 20 of the coordinate measuring machine 1. In some examples, the motion system of the coordinate measuring machine 1 may also be referred to as a motion system, a sliding system, a moving device, or a guide rail 11 structure.
[0031] In some examples, a coordinate measuring machine 1 can refer to an instrument capable of measuring geometric shapes, lengths, and circumferential divisions within a six-sided spatial area; it is also called a coordinate measuring machine or a coordinate measuring machine bed. In some examples, a coordinate measuring machine can be an instrument with a detector that can move in three directions on three mutually perpendicular guide rails 11. This detector transmits signals in a contact or non-contact manner, and the displacement measurement system of the three axes (such as a linear scale) calculates the x, y, z points of the workpiece and various functional measurements using a data processor or computer. The measurement functions of a coordinate measuring machine should include dimensional accuracy, positioning accuracy, geometric accuracy, and contour accuracy.
[0032] See in some examples Figure 1 and Figure 2 The coordinate measuring machine 1 may include a motion system and a probe 20. In some examples, the motion system can control the probe 20 to move along the x-axis, y-axis, or z-axis. In some examples, the motion system may include a first motion structure, a second motion structure, and a third motion structure. The first motion structure controlling the probe 20 to move along the z-axis may be disposed within the second motion structure controlling the probe 20 to move along the x-axis, and the second motion structure controlling the probe 20 to move along the x-axis may be disposed within the third motion structure controlling the probe 20 to move along the y-axis. In other words, the third motion structure can control the second structure to move along the y-axis, thereby causing the first motion structure to move along the y-axis, and thus causing the probe 20 to move along the y-axis; the second motion structure can control the first structure to move along the x-axis, thereby causing the probe 20 to move along the x-axis. In this case, the probe 20 can be controlled to move along the x-axis, y-axis, or z-axis. In some examples, the x-axis and y-axis may be axes located in a horizontal plane, and the z-axis may be an axis located in a vertical plane.
[0033] In some examples, the slider layout disclosed herein can be applied to the first, second, or third motion structure, thereby improving the stiffness of the first, second, or third motion structure, and consequently enhancing their structural stability. Preferably, the slider layout can be applied to the third motion structure. In this case, if the first motion structure is positioned above the second motion structure and the second structure is positioned above the third motion structure, the gravity of the first and second motion structures will act on the third motion structure, resulting in a stronger force on the third motion structure. Therefore, compared to the first and second motion structures, the third motion structure is more prone to instability. Utilizing the slider layout disclosed herein in the third motion structure can effectively improve its structural stability.
[0034] Figure 3This is a schematic diagram showing the structure of the guide rail 11 and the worktable 14 according to the embodiments of this disclosure.
[0035] See in some examples Figure 1 , Figure 2 and Figure 3 The motion system may include a worktable 14 for carrying the workpiece. In this case, the workpiece can be placed on the worktable 14, and the motion system can control the probe 20 to measure the workpiece located on the worktable 14. However, this disclosure is not limited to this; the motion system may also be provided without a worktable 14, for example, the motion system can be used to control the probe 20 to measure the workpiece at any position.
[0036] In some examples, the worktable 14 and the guide rail 11 may be integrally formed. In some examples, the worktable 14 and the guide rail 11 may be made of marble.
[0037] In some examples, a first cutting groove 122a and a second cutting groove 122b (described later) can be machined into the marble to form a worktable 14 and a guide rail 11.
[0038] Figure 4 This is a schematic diagram showing the connection structure of the guide rail 11, slider and base 12 according to the embodiments of this disclosure.
[0039] See in some examples Figure 4 The motion system may include a guide rail 11, a base 12 having a groove and surrounding the guide rail 11 through the groove, and a plurality of sliders disposed in the groove and movable relative to the guide rail 11. In this case, the sliders are able to slide on the guide rail 11, and the plurality of sliders surrounding the guide rail 11 can generate forces in different directions on the base 12.
[0040] In some examples, the multiple sliders may include a first slider 13a for applying a first force to the base 12 in a first direction D1, a second slider 13b for applying a second force to the base 12 in a second direction D2, a third slider 13c for applying a third force to the base 12 in a third direction D3, and a fourth slider 13d for applying a fourth force to the base 12 in a fourth direction D4. The first direction D1 is opposite to the third direction D3, the second direction D2 is opposite to the fourth direction D4, and the first direction D1 is orthogonal to the second direction D2. The guide rail 14 includes a second plane 121b opposite to the second slider 13b and a fourth plane 121d opposite to the fourth slider 14b. The second plane 121b is parallel to the fourth plane 121d, and the fourth direction D4 is perpendicular to the fourth plane 121d (described later). When the second plane 121b is adjusted to a horizontal plane, the fourth direction D4 is the direction of gravity. In this configuration, force and torque balance of the base 12 can be easily achieved through two pairs of orthogonal forces. Simultaneously, before using the coordinate measuring machine 1, it needs to be adjusted so that the second plane 121b is level, at which point the fourth direction D4 is the direction of gravity. Since the fourth direction D4 is the direction of gravity, a second force pointing in the second direction D2 can be applied to the base 12 using the second slider 13b to balance the forces pointing in the fourth direction D4, such as gravity, thereby achieving force and torque balance and improving the stability of the base 12 when sliding on the guide rail 11.
[0041] In some examples, the slider can be an air-bearing slider. This allows gas to be ejected from the air-bearing slider towards the guide rail 11, creating a gap between the slider and the guide rail 11, thereby reducing friction and enabling the slider to slide stably on the guide rail 11. In some examples, the gap between the slider and the guide rail 11 can also be referred to as an air layer. In some examples, the air pressure of multiple air-bearing sliders can be the same; for example, the air pressure of each slider can be 0.4 MPa. In this case, the air pressure of multiple sliders can be controlled to remain stable simultaneously, and if any direction is subjected only to the force exerted by the air pressure of the air-bearing slider, the magnitude of the force exerted by the slider in that direction can be made the same.
[0042] In some examples, the slider can also be a slider that reduces the friction between the slider and the guide rail 11 using other levitation technologies, including but not limited to magnetic levitation, acoustic levitation, and electro-levitation. In this case, levitation technology can be used to create a gap between the slider and the guide rail 11, thereby reducing the friction between them.
[0043] In some examples, the guide rail 11 can be a guide rail extending in any direction. For example, the guide rail 11 can be a guide rail extending along the y-axis, thereby controlling the movement of the probe 20 along the y-axis; the guide rail 11 can be a guide rail extending along the x-axis, thereby controlling the movement of the probe 20 along the x-axis; or the guide rail 11 can be a guide rail extending along the z-axis, thereby controlling the movement of the probe 20 along the z-axis. See also Figure 1 and Figure 2 The guide rail 11 can be a guide rail 11 extending along the y-axis.
[0044] In some examples, each orientation can be defined by a first direction D1, a second direction D2, a third direction D3, and a fourth direction D4. For example, in any structure (e.g., guide rail 11, base 12, or worktable 14), the side facing the second direction D2 can be the top (or above), the side facing the fourth direction D4 can be the bottom (or below), the side facing the third direction D3 can be the left side, and the side facing the first direction D1 can be the right side.
[0045] Figure 5 It shows Figure 4 A planar schematic diagram of guide rail 11.
[0046] See in some examples Figures 1-3 When the coordinate measuring machine 1 has a worktable 14, the guide rail 11 can be disposed on one side of the worktable 14. See some examples. Figure 4 The guide rail 11 can be located in the first direction D1 of the worktable 14.
[0047] See in some examples Figure 5 The guide rail 11 includes a first guide rail region 111 and a second guide rail region 112 arranged sequentially along the first direction D1. The solid line represents the guide rail 11, and the dashed line represents the worktable 14.
[0048] See in some examples Figure 4 and Figure 5 The first guide rail area 111 can be set in the first direction D1 of the worktable 14, and the second guide rail area 112 can be set in the first direction D1 of the first guide rail area 111.
[0049] In some examples, the first guide rail region 111 in guide rail 11 may be a region with higher structural stability, and the second guide rail region 112 in guide rail 11 may be a region with lower structural stability relative to the first guide rail region 111. Specifically, see [link to documentation]. Figure 5Along the fourth direction D4, the thickness of the first guide rail region 111 can be greater than the thickness of the second guide rail region 112. In this case, the portion of the guide rail 11 with a higher thickness along the fourth direction D4 has higher structural stability when subjected to forces along the second direction D2 or the fourth direction D4. Simultaneously, due to the influence of gravity (i.e., the force pointing towards the fourth direction D4) of the motion system, the guide rail 11 is more susceptible to the effects of gravity, thus the first guide rail region 111 can have higher structural stability or higher stiffness. Meanwhile, since the second guide rail region 112 has a smaller thickness, a fourth slider 13d can be provided at the bottom of the second guide rail region 112, thereby providing a force towards the fourth direction D4 to the base 12, thus preventing the base 12 or the right column 15 (described later) from tipping over due to uneven force distribution. However, this disclosure is not limited to this; in some examples, the thickness of the first guide rail region 111 can be the same as the thickness of the second guide rail region 112, thereby further improving the stiffness of the guide rail 11. See also... Figure 4 Since the bottom of the second guide rail region 112 is already provided with the fourth slider 13d, it is difficult to support the second guide rail region 112 at the bottom (that is, the second guide rail region 112 is in a suspended state). When the second guide rail region 112 is subjected to a force pointing in the fourth direction D4, in order to maintain the force balance, it is necessary to use the internal force between the first guide rail region 111 and the second guide rail region 112 to balance the force pointing in the fourth direction D4. Therefore, compared with the first guide rail region 111 which does not have a slider at the bottom, the structural stability of the second guide rail region 112 is lower.
[0050] It should be noted that structural stability can be understood as follows: as the force increases, the guide rail 11 or the base 12 may deform, or even break (or become unstable). When two structures are subjected to the same magnitude of force from the same object (e.g., a slider) (e.g., a force pointing in the fourth direction D4), if the deformation of one structure is smaller or it is less likely to break (or become unstable), then that structure can be considered to have higher structural stability than the other structure.
[0051] See in some examples Figure 4 and Figure 5 When the thickness of the first guide rail region 111 is greater than the thickness of the second guide rail region 112, the first guide rail region 111 and the second guide rail region 112 in the guide rail 11 can cooperate to form a first cutting groove 122a. In this case, the fourth slider 13d can be disposed in the first cutting groove 122a. In some examples, the first cutting groove 122a can be obtained by cutting a portion of the structure in the guide rail 11. In some examples, when there is no first cutting groove 122a, the fourth slider 13d can also be disposed at the bottom of the second guide rail region 112.
[0052] See in some examples Figure 4 and Figure 5 A second cutting groove 122b can be provided between the worktable 14 and the first guide rail area 111. In this case, a third slider 13c can be positioned in the second cutting groove 122b. In some examples, when there is no second cutting groove 122b (or when there is no worktable 14), the third slider 13c can also be positioned on the left side of the first guide rail area 111.
[0053] See in some examples Figure 4 and Figure 5 The guide rail 11 may include a first plane 121a opposite to the first slider 13a, a second plane 121b opposite to the second slider 13b, a third plane 121c opposite to the third slider 13c, and a fourth plane 121d opposite to the fourth slider 13d. A first direction D1 is perpendicular to the first plane 121a, a second direction D2 is perpendicular to the second plane 121b, a third direction D3 is perpendicular to the third plane 121c, and a fourth direction D4 is perpendicular to the fourth plane 121d. In other words, the first plane 121a can be parallel to the third plane 121c, the second plane 121b can be parallel to the fourth plane 121d, and the first plane 121a can be perpendicular to the second plane 121b. In this case, the planes can effectively reduce the friction between the guide rail 11 and the sliders, while also allowing the sliders to maintain linear motion during sliding, thus improving the stability of the base 12's movement.
[0054] In some examples, before using the motion system, the second plane 121b can be adjusted to a horizontal plane (also known as leveling the second plane 121b). Since the second plane 121b may not be parallel to the horizontal plane during the installation of the coordinate measuring machine 1, the fourth direction D4 may not coincide with the direction of gravity. Adjusting the second plane 121b to a horizontal plane allows the fourth direction D4 to coincide with the direction of gravity, meaning the second direction D2 is opposite to gravity, facilitating the use of a second force pointing towards the second direction D2 to balance gravity.
[0055] Figure 6 It shows Figure 4 A three-dimensional schematic diagram of the slider and base 12.
[0056] In some examples, as described above, the motion system may include a base 12 having a groove and surrounding the guide rail 11 through the groove. Specifically, the base 12 may have a groove, the width of which may be greater than the thickness of the guide rail 11 along the first direction D1. Thus, the guide rail 11 can be disposed in the groove of the base 12.
[0057] See in some examples Figure 6A right column 15 may be provided at the top of the base 12.
[0058] See in some examples Figure 2 The motion system may include a crossbeam 16 extending along the X-axis. The crossbeam 16 may be column-shaped, and columns may be provided at the bottom of both ends of the crossbeam 16. Specifically, a left column 17 may be provided at the bottom of the left side of the crossbeam 16, and a right column 15 may be provided at the bottom of the right side of the crossbeam 16. In some examples, the crossbeam 16, the left column 17, and the right column 15 may be combined to form a gantry structure.
[0059] In some examples, a slider can be provided at the bottom of the left column 17. The slider provided on the left column 17 can obtain a reaction force pointing in the second direction D2 by applying force to the worktable 14. In this case, the stability of the gantry structure can be further improved by the reaction force pointing in the second direction D2, thereby improving the stability of the movement of the third motion structure.
[0060] However, this disclosure is not limited to this. In some examples, the bottom of the left column 17 may not be equipped with a slider, or in some examples, the left column 17 may not be equipped at all. In this case, since the base 12 of the right column 15 is already subjected to four opposing and orthogonal forces applied by the slider (a first force pointing in the first direction D1, a second force pointing in the second direction D2, a third force pointing in the third direction D3, and a fourth force pointing in the fourth direction D4), even if a slider is provided on the left column 17, the torque balance and force balance of the gantry can be achieved by adjusting the position of the four forces. This simplifies the gantry structure and reduces its weight while ensuring torque balance and force balance. At the same time, force balance and moment balance can be completed inside the base 12. In this case, the force will not be transmitted to the crossbeam 16 and the left column 17. Since force balance and moment balance need to be achieved through force and moment, and force and moment will cause deformation, if force balance and moment balance are completed inside the base 12 (that is, the force and moment are restricted to the base 12), the deformation will only exist in the base 12, which can reduce the influence of force and moment on the crossbeam 16 and the left column 17, thereby reducing the deformation of the crossbeam 16 and the left column 17.
[0061] See in some examples Figure 6 The slider can be set on the inner wall of the groove in the base 12.
[0062] In some examples, as described above, the slider may include at least one first slider 13a, at least one second slider 13b, at least one third slider 13c, and at least one fourth slider 13d; in other words, the number of first slider 13a, second slider 13b, third slider 13c, and fourth slider 13d may be one or more. For example, see [link to relevant documentation]. Figure 6 The inner wall of the groove in the base 12 can be provided with two first sliders 13a and two fourth sliders 13d. In this case, providing multiple sliders in the same direction can apply more force to the base 12, while increasing the force-bearing area of the fourth slider 13d, further improving the stability of the base 12 (which can also be the right column 15 or a gantry structure) during movement.
[0063] In some examples, the slider can be set in a specific layout on the base 12 or placed at a specific position on the guide rail 11 to improve the structural stability of the guide rail. For example, the layout of the slider can refer to the relative positional relationship between the slider and the guide rail 11.
[0064] In some examples, the second slider 13b can be positioned in a region of high structural stability of the guide rail 11. In this case, since gravity points in the fourth direction D4, and the second slider 13b applies a first force to the base 12 in the second direction D2, which is opposite to the fourth direction D4, at least a portion of the first force applied by the second slider 13b to the base 12 is needed to balance the gravity (e.g., the gravity of a gantry structure) while keeping the base 12 in a stable state. Thus, the force between the second slider 13b and the guide rail 11 is larger than that between other sliders. Positioning the second slider 13b in a region of high structural stability of the guide rail 11 can improve the structural stability of the guide rail 11.
[0065] See in some examples Figure 4The third slider 13c and the second slider 13b are disposed between the base 12 and the first guide rail region 111, while the first slider 13a and the fourth slider 13d are disposed between the base 12 and the second guide rail region 112. In this case, since the fourth slider 13d is not disposed at the bottom of the first guide rail region 111, i.e., it is not in a suspended state, it can have higher structural stability (i.e., the first guide rail region 111 can better withstand the force pointing in the fourth direction). Thus, the guide rail 11 can maintain a stable state even under the large force applied by the second slider 13b. At the same time, since the second slider 13b is disposed between the base 12 and the first guide rail region 111, and the fourth slider 13d is disposed between the base 12 and the second guide rail region 112, it is horizontally stable. The direction (i.e., the x-axis direction) is not symmetrical about the guide rail 11. When the base 12 (or gantry structure) is subjected to the second force applied by the second slider 13b and the fourth force applied by the fourth slider 13d, it is difficult to achieve torque balance. Therefore, the third slider 13c, which is set between the base 12 and the first guide rail region 111, and the first slider 13a, which is set between the base 12 and the second guide rail region 112, can achieve torque balance through the first force and the third force, thereby ensuring the stability of the base 12 (or gantry structure) during movement.
[0066] It should be noted that the slider being positioned between the base 12 and the first guide rail region 111 can be understood as follows: the slider includes a sliding surface facing the guide rail 11, and the force exerted by the slider on the guide rail 11 can be simplified as a force passing through the geometric center of the sliding surface and perpendicular to the sliding surface. When the point of application of this force on the guide rail 11 is located in the first guide rail region 111, it can be considered that the slider is positioned between the base 12 and the first guide rail region 111. For example, if the second slider 13b is positioned between the base 12 and the first guide rail region 111, and when the second slider 13b forms an air layer with the guide rail 11 (when the air-bearing slider is working and suspended on the guide rail 11), the point of application of the force exerted by the second slider 13b on the guide rail 11 in the fourth direction D4 can be located in the first guide rail region 111. In other words, the sliding surface of the second slider 13b can partially act on the second guide rail region 112 or it can have no force action on the second guide rail region 112 at all, but the geometric center of the sliding surface of the second slider 13b will be located at the top of the first guide rail region 111.
[0067] See in some examples Figure 4 The sliding surface of the second slider 13b is larger than that of the first slider 13a, the third slider 13c, and the fourth slider 13d. In this case, since the force applied and the reaction force received by the second slider 13b are larger, increasing the sliding surface of the second slider 13b can optimize the stress distribution and reduce the occurrence of adverse conditions caused by stress concentration.
[0068] Figure 7 This is a schematic diagram showing the connection structure of the guide rail 11, slider and base 12 in an embodiment in which the slider is arranged in a symmetrical manner. Figure 8 This disclosure illustrates Figure 7 Implementation methods and Figure 5 A schematic diagram illustrating variations in the implementation method. Wherein, Figure 8 The dashed part in the middle is Figure 7 The guide rail 11 and slider involved in the implementation method are shown in solid lines. Figure 5 The guide rail 11 and slider involved in the implementation method.
[0069] See in some examples Figure 7 The sliders are arranged symmetrically on the guide rail 11, that is, the second slider 13b and the fourth slider 13d are symmetrical about the horizontal plane on the guide rail 11, and the first slider 13a and the third slider 13c are symmetrical about the vertical plane on the guide rail 11. Since the second slider 13b will exert a large force on the guide rail 11 in the fourth direction D4, in order to maintain the force balance, it is necessary to rely on the internal force between the first guide rail area 111 and the second guide rail area 112 to balance the force. In the long-term use, the structural stability of the guide rail 11 is easily reduced.
[0070] In some examples, the second slider 13b is located at one end of the second plane 121b near the third plane 121c. Specifically, in some examples, see [link to example]. Figure 8 Instead of symmetrically arranging the sliders on the guide rail 11, the second slider 13b can be moved to the left, that is, the point of application of the force exerted by the second slider 13b on the guide rail 11 can be moved towards the third direction D3. This allows the point of application of the force to be moved to a region with higher structural stability. Simultaneously, the second slider 13b can be moved to the end of the second plane 121b. In this case, the force exerted by the second slider 13b on the guide rail 11 can be concentrated at the end of the second plane 121b near the third plane 121c, further moving the point of application of the force exerted by the second slider 13b on the guide rail 11 to a region with the highest possible structural stability.
[0071] In some examples, the third slider 13c can be located at the end of the third plane 121c close to the second plane 121b. In this case, the depth of the second cutting groove 122b can be minimized. Since the smaller the depth of the second cutting groove 122b, the less part needs to be cut during processing, and the higher the rigidity of the guide rail 11.
[0072] See in some examples Figure 8The fourth slider 13d can be located at the end of the fourth plane 121d close to the first plane 121a. In this case, the depth of the first cutting groove 122a can be reduced as much as possible. Since the smaller the depth of the first cutting groove 122a, the less part needs to be cut during processing, and the higher the rigidity of the guide rail 11.
[0073] Figure 9 This is a schematic diagram showing the forces acting on the base 12 according to an embodiment of the present disclosure.
[0074] In some instances, the specific positions of the first slider 13a, the second slider 13b, the third slider 13c, and the fourth slider 13d can be determined through torque balance and force balance.
[0075] In some instances, see Figure 9 The base 12 can be subjected to a first force, a second force, a third force, a fourth force, and gravity.
[0076] In some instances, the first, second, third, and fourth forces, along with gravity, can satisfy the following formula:
[0077] F2*L2=F4*L4+G*LG,
[0078] F1*L1=F3*L3,
[0079] G+F4=F2,
[0080] F1 = F3,
[0081] Wherein, F1 represents the first force, F2 represents the second force, F3 represents the third force, F4 represents the fourth force, G represents gravity, L1 represents the lever arm of the first force, L2 represents the lever arm of the second force, L3 represents the lever arm of the third force, L4 represents the lever arm of the fourth force, and LG represents the lever arm of gravity. It should be noted that gravity can be a force acting on the base 12 in the fourth direction D4, generated by the weight of the base 12 (including the weight of the base 12, the right column 15, or the beam 16, etc.).
[0082] In some instances, a support structure may be provided at the bottom of the first guide rail region 111. In this case, the support structure can be used to apply a force pointing in the second direction D2 to the first guide rail region 111, thereby reducing the internal force between the first guide rail region 111 and the worktable 14, which in turn reduces the deformation of the guide rail 11 and the worktable 14, improves the accuracy and rigidity of the guide rail 14, and thus improves the structural stability of the guide rail 11.
[0083] In some instances, graduations may be provided on the surface of the guide rail 11 or the inner wall of the groove, in which case the slider can be conveniently positioned to achieve torque balance.
[0084] While the present disclosure has been specifically described above in conjunction with the accompanying drawings and embodiments, it is to be understood that the above description does not limit the present disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from its essential spirit and scope, and all such modifications and variations fall within the scope of the present disclosure.
Claims
1. A motion system for a coordinate measuring machine (CMM), comprising a motion system disposed on the CMM and controlling the movement of the CMM's probe, characterized in that, The motion system includes a guide rail, a base having a groove and surrounding the base of the guide rail through the groove, and a plurality of sliders disposed in the groove and movable relative to the guide rail in a manner surrounding the guide rail. The plurality of sliders includes a first slider for applying a first force to the base in a first direction, a second slider for applying a second force to the base in a second direction, a third slider for applying a third force to the base in a third direction, and a fourth slider for applying a fourth force to the base in a fourth direction. The first direction is opposite to the third direction, the second direction is opposite to the fourth direction, and the first direction is orthogonal to the second direction. The guide rail includes a second plane opposite to the second slider and a fourth plane opposite to the fourth slider. The second plane is parallel to the fourth plane, and the fourth direction is perpendicular to the fourth plane. When the second plane is adjusted to a horizontal plane, the fourth direction is the direction of gravity. The guide rail includes a first guide rail region and a second guide rail region arranged sequentially along the first direction. The third slider and the second slider are disposed between the base and the first guide rail area, and the first slider and the fourth slider are disposed between the base and the second guide rail area. The fourth slider and the second slider are not symmetrical about the guide rail in the horizontal direction and achieve torque balance through the third force applied by the third slider and the first force applied by the first slider. Along the fourth direction, the thickness of the first guide rail region is greater than the thickness of the second guide rail region, a support structure is provided at the bottom of the first guide rail region, the slider includes a sliding surface facing the guide rail, and the sliding surface of the second slider is greater than that of the first slider, the third slider, and the fourth slider.
2. The motion system according to claim 1, characterized in that: The slider is an air-float slider.
3. The motion system according to claim 2, characterized in that: The guide rail includes a first plane opposite to the first slider and a third plane opposite to the third slider.
4. The motion system according to claim 3, characterized in that: The second slider is located at one end of the second plane near the third plane.
5. The motion system according to claim 3, characterized in that: The third slider is located at one end of the third plane near the second plane.
6. The motion system according to claim 3, characterized in that: The fourth slider is located at one end of the fourth plane that is closer to the first plane.
7. The motion system according to claim 1, characterized in that: It includes a worktable for carrying workpieces, and the first guide rail area is disposed on one side of the worktable.