Ball screw with feedback on force status

Abstract

A ball screw with feedback capability is applied to a mounting platform. The ball screw includes a screw shaft, a nut seat, and at least one force sensor module. The screw shaft includes a rod extending along an axis and a guide groove formed in the rod in a helical manner around the axis. The nut seat includes a base rotatably fitted around the rod for mounting on the mounting platform. The base has a support portion for supporting the mounting platform. The at least one force sensor module is connected to the nut seat and is adapted to abut against the mounting platform to measure the force applied by the mounting platform to the nut seat. This allows the force applied by the mounting platform to the nut seat to be measured, improving the accuracy of use and enabling the determination of the screw shaft offset. Since the nut seat is a single component, its rigidity is not compromised.

Description

Technical Field

[0001] This invention relates to a ball screw, and more particularly to a ball screw capable of providing feedback on the applied force. Background Technology

[0002] An existing ball screw, as shown in Taiwan Patent Certificate No. TW I513927B, includes a screw member, a nut assembly rotatably disposed on the screw member, and two parallelism sensors disposed on the nut assembly. The nut assembly has two nut members that can be joined together along the axial direction of the screw member, and the parallelism sensors are disposed opposite to each other along the radial direction of the screw member and are clamped between the nut members.

[0003] In use, the parallelism of the assembled ball screw can be determined by simultaneously comparing the pressure measured by the parallelism sensor.

[0004] However, using two nuts to assemble and clamp the parallelism sensor results in poor rigidity of the nut assembly, which prevents the accuracy from being improved. Summary of the Invention

[0005] The purpose of this invention is to provide a ball screw with a feedback force state that overcomes the shortcomings of the prior art.

[0006] This invention relates to a ball screw capable of providing feedback on force application, applied to a mounting platform. The ball screw includes a screw shaft comprising a rod extending along an axis and a guide groove formed in the rod in a helical manner around the axis. The ball screw also includes a nut seat and at least one force sensor module. The nut seat includes a base rotatably fitted around the rod for mounting on the mounting platform. The base has a support portion for supporting the mounting platform. The at least one force sensor module is connected to the nut seat and adapted to abut against the mounting platform to measure the force applied by the mounting platform to the nut seat.

[0007] The ball screw capable of providing feedback on the force state according to the present invention further includes at least one mounting groove, which is located in the nut seat and is used to accommodate the at least one force sensor module.

[0008] The ball screw capable of feedback of force state according to the present invention has a seat body that further has a flange portion connected to the bearing portion along the extension direction of the axis. The outer contour of the flange portion in the section perpendicular to the axis is larger than the outer contour of the bearing portion in the section perpendicular to the axis. The at least one mounting groove is located on the side of the flange portion adjacent to the bearing portion along the extension direction of the axis and on the side of the flange portion away from the bearing portion in the direction perpendicular to the axis. The at least one force sensor module is housed in the at least one mounting groove and connected to the flange portion to abut against the mounting platform.

[0009] The ball screw of the present invention, which can provide feedback on the force state, wherein the at least one mounting groove is located on one side of the bearing portion along the extension direction of the axis and on the side of the bearing portion away from the axis in a direction perpendicular to the axis, and the at least one force sensor module is housed in the at least one mounting groove and connected to the bearing portion to abut against the mounting platform.

[0010] The ball screw capable of providing feedback on the applied force state according to the present invention includes multiple force sensor modules and multiple mounting slots, wherein the mounting slots are arranged at angular intervals around the axis to accommodate the force sensor modules respectively.

[0011] The ball screw with feedback capability according to the present invention includes a force sensor module. The mounting platform includes a base and a mounting hole through the base for the seat body to pass through. The mounting hole has a large-diameter section and a small-diameter section arranged opposite to each other. The force sensor module includes a collar arranged around the axis and a plurality of force sensing elements connected within the collar. The force sensing elements are arranged at angular intervals around the axis. The seat body also has a flange portion connected to the bearing portion along the extension direction of the axis. The bearing portion and the flange portion are respectively located within the small-diameter section and the large-diameter section. The outer contour of the flange portion in the cross section perpendicular to the axis is larger than the outer contour of the bearing portion in the cross section perpendicular to the axis. The collar is sleeved on the outside of the flange portion to abut against the base adjacent to the large-diameter section. The force sensing elements abut against the flange portion. The collar and the flange portion are locked together by threads.

[0012] The ball screw capable of feedback of force state of the present invention includes a mounting platform comprising a base and at least one screw fastener screwed to the base. The base also has a flange portion connected to the bearing portion along the extension direction of the axis. The outer contour of the flange portion in a section perpendicular to the axis is larger than the outer contour of the bearing portion in a section perpendicular to the axis. The at least one mounting groove is located on the side of the flange portion opposite to the bearing portion along the extension direction of the axis. The at least one force sensor module is accommodated in the at least one mounting groove and connected to the flange portion, so that the at least one screw fastener passes through the at least one mounting groove and the at least one force sensor module to be screwed to the base.

[0013] The ball screw capable of providing feedback on force status according to the present invention includes multiple force sensor modules, multiple mounting slots, and multiple through slots located on one side of the flange portion adjacent to the bearing portion along the extension direction of the axis and respectively communicating with the mounting slots. The force sensor modules are annular, and the diameters of the through slots are respectively smaller than the diameters of the mounting slots. The mounting slots are arranged at angular intervals around the axis to accommodate the force sensor modules respectively. The mounting platform also includes multiple screw fasteners, each screw fastener having a corresponding mounting slot and abutting against the head of its respective force sensor module, and a rod portion connecting the head and passing through the force sensor module and its respective through slot to be fixed to the base.

[0014] The ball screw with feedback force state of the present invention can perform a detection process to determine the offset direction of the screw shaft. In the detection process, the mounting stage is set on a slide group, the slide group has two slide rails and a slide seat movably set on the slide rails and connected to the mounting stage. The nut seat is driven by the screw shaft to move along the axis and drive the mounting stage to move along the slide rails to a first position. The force measured at the first position is recorded as a first force information by a controller electrically connected to at least one force sensor module. Then the nut seat is moved to a second position and... The controller records the force measured at the second position as a second force information. The controller determines the offset direction of the screw shaft based on the magnitude of the first force information and the second force information. When the second force information is less than the first force information, it is determined that the screw shaft extends from the first position to the second position and is offset in a direction away from the force sensor module along the axis at the second position. When the second force information is greater than the first force information, it is determined that the screw shaft extends from the first position to the second position and is offset in a direction adjacent to the force sensor module along the axis at the second position.

[0015] The beneficial effects of the present invention are as follows: by providing at least one force sensor module on the nut seat, the force applied to the nut seat by the mounting platform can be measured, thereby improving the accuracy of use and being able to determine the offset of the screw shaft. Since the nut seat is a single component, its rigidity will not be compromised. Attached Figure Description

[0016] Figure 1 This is a three-dimensional composite diagram of a first embodiment of the ball screw with feedback force state of the present invention;

[0017] Figure 2 This is an exploded perspective view of the first embodiment;

[0018] Figure 3 This is a three-dimensional combined view of the first embodiment, a mounting platform, and a slide assembly;

[0019] Figure 4 This is a schematic diagram of the first embodiment, illustrating that a nut holder moves to a first position;

[0020] Figure 5 It is similar to Figure 4 The view illustrates that the nut seat has been moved to a second position;

[0021] Figure 6 This is a three-dimensional composite diagram of a second embodiment of the ball screw with feedback force state of the present invention;

[0022] Figure 7 This is an exploded perspective view of the second embodiment;

[0023] Figure 8 This is a three-dimensional composite diagram of a third embodiment of the ball screw with feedback force state of the present invention;

[0024] Figure 9 This is an exploded perspective view of the third embodiment;

[0025] Figure 10 This is a three-dimensional composite diagram of a fourth embodiment of the ball screw with feedback force state of the present invention;

[0026] Figure 11 This is an exploded perspective view of the fourth embodiment. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] For ease of explanation, the same elements are represented by the same reference numerals in the following embodiments.

[0029] See Figure 1 , 2 3. A first embodiment of the ball screw with feedback force status of the present invention is applied to a mounting platform 91. The mounting platform 91 includes a base 911 and a mounting hole 912 through the base 911. The ball screw with feedback force status includes a screw shaft 2, a nut seat 3, six force sensor modules 4, and six mounting slots 5.

[0030] The screw shaft 2 includes a rod body 21 extending along an axis L, and a guide groove 22 formed in the rod body 21 in a spiral manner around the axis L.

[0031] The nut seat 3 includes a base 31 that is rotatably fitted around the rod 21 for mounting the mounting platform 91. The base 31 has a support portion 311 that passes through the mounting hole 912 and is used to support the mounting platform 91, and a flange portion 312 that connects to the support portion 311 and abuts against the base 911 along the extension direction of the axis L.

[0032] The outer contour of the flange portion 312 in the section perpendicular to the axis L is greater than the outer contour of the bearing portion 311 in the section perpendicular to the axis L.

[0033] The force sensor module 4 is connected to the nut seat 3 to abut against the mounting platform 91 to measure the force applied by the mounting platform 91 to the nut seat 3. The force sensor modules 4 are respectively housed in the mounting groove 5 and connected to the flange portion 312. In this embodiment, each force sensor module 4 is made of a strain gauge, but it is not limited to this; any sensing element that can be used to measure force can be used in this application.

[0034] Each mounting slot 5 is located on the side of the flange portion 312 adjacent to the support portion 311 along the extension direction of the axis L and on the side of the flange portion 312 away from the support portion 311 along the direction perpendicular to the axis L. The mounting slots 5 are arranged at angular intervals around the axis L to accommodate the force sensor module 4 respectively.

[0035] See Figure 3 , 45. In use, the ball screw that can provide feedback on the force state can perform a detection process under the control of a controller (not shown) electrically connected to the force sensor module 4, thereby determining the offset direction of the screw shaft 2. In the detection process, the mounting platform 91 is first set on a slide group 92. The slide group 92 has two slide rails 921 and a slide seat 922 that is movably set on the slide rails 921 and connected to the mounting platform 91. The screw shaft 2 can be rotated by a drive motor (not shown) electrically connected to the controller, thereby causing the nut seat 3 to move along the screw shaft 2.

[0036] Then, the nut seat 3 is driven by the screw shaft 2 to move along the axis L, which in turn moves the mounting platform 91 along the slide rail 921 to a first position (see...). Figure 4 The controller records the force measured by each force sensor module 4 at the first position as a first force information.

[0037] Next, the nut seat 3 is moved to a second position (see...). Figure 5 The controller records the force measured at the second position as a second force information.

[0038] The controller determines the offset direction of the screw shaft 2 based on the magnitudes of the first force information and the second force information. When the second force information is less than the first force information, it determines that the screw shaft 2 extends from the first position to the second position, and at the second position, it offsets in a direction away from the force sensor module 4 along the axis L. When the second force information is greater than the first force information, it determines that the screw shaft 2 extends from the first position to the second position, and at the second position, it offsets in a direction adjacent to the force sensor module 4 along the axis L. It should be noted that the controller can notify the user of the determined offset direction through screen display or indicator light display, but is not limited to these display methods.

[0039] by Figure 4 , 5To further illustrate, the screw shaft 2 is offset from the upper left to the lower right in the figure. The force applied by the mounting platform 91 to the nut seat 3 is directly applied to the force sensor module 4. When the nut seat 3 moves from the first position on the left to the second position on the right, since the slide 922 moves along the slide rail 921, the force sensor module 4 located on the upper side in the figure will be subjected to the force applied by the mounting platform 91 to the nut seat 3 during the movement. Furthermore, since the structural rigidity between the slide rail 921, the slide 922, and the mounting platform 91 is greater than that between the mounting platform 91 and the nut seat 3, the force sensor module 4 located on the upper side in the figure will be subjected to the force applied by the mounting platform 91 to the nut seat 3. Due to the structural rigidity between the nut seats 3, the mounting platform 91 will guide the movement path of the nut seats 3 back to a direction parallel to the extension direction of the slide rail 921, thereby making the corresponding first force information greater than the second force information. This means that when the corresponding force sensor module 4 moves from the first position to the second position, the force it receives gradually decreases. In other words, it means that the right side of the screw shaft 2 is offset away from the force sensor module 4 towards the axis L. Since the force sensor module 4 on the upper side of the figure is located on the upper side of the axis L, it can be determined that the right side of the screw shaft 2 is offset towards the lower side.

[0040] Additionally, when the nut seat 3 moves from the first position on the left to the second position on the right, the force sensor module 4 located on the lower side of the figure will be subjected to the force applied to the nut seat 3 by the mounting platform 91, causing the corresponding first force information to be less than the second force information. This means that when the corresponding force sensor module 4 moves from the first position to the second position, the force it receives gradually increases. In other words, it means that the right side of the screw shaft 2 is shifted towards the axis L adjacent to the force sensor module 4. Since the force sensor module 4 on the lower side of the figure is located below the axis L, it can be determined that the right side of the screw shaft 2 is shifted downwards.

[0041] The measurement results from two force sensor modules 4 in opposite positions can be used to verify each other. However, it should be noted that since only one force sensor module 4 is needed to determine the offset direction of the screw shaft 2, in other embodiments, only one force sensor module 4 can be set up to achieve the same effect.

[0042] Since the force sensor module 4 can provide feedback on the force applied, it is possible to determine whether the installation state of the screw shaft 2 is misaligned. Compared to existing ball screws, which use two nuts to form a nut assembly and thus suffer from poor rigidity, the ball screw that can provide feedback on the force applied can achieve higher rigidity by setting the mounting groove 5 in a single nut seat 3, thereby improving the accuracy of use. Furthermore, since each force sensor module 4 can provide feedback on the force applied, it is not necessary to use two parallelism sensors in conjunction with each other as is the case with existing ball screws. A single force sensor module 4 can operate independently, making it more convenient and flexible to use.

[0043] It should be noted that in this embodiment, the number of force sensor modules 4 and mounting slots 5 are six, but it is not limited to this. In addition to one, the number can also be four, or more other types of quantities.

[0044] See Figure 6 , 7 A second embodiment of the present invention is similar to the first embodiment, except that:

[0045] The seat 31 has the bearing portion 311.

[0046] The number of force sensor modules 4 is four, and the number of mounting slots 5 is four.

[0047] The mounting groove 5 is located on one side of the support portion 311 along the extension direction of the axis L and on the side of the support portion 311 away from the axis L in a direction perpendicular to the axis L. The force sensor modules 4 are respectively housed in the mounting groove 5 and connected to the support portion 311 to abut against the mounting platform 91.

[0048] The mounting slots 5 are arranged at angular intervals around the axis L to accommodate the force sensor modules 4 respectively.

[0049] When in use, the force applied by the mounting platform 91 to the nut seat 3 will be directly applied to the force sensor module 4.

[0050] Thus, the second embodiment can also achieve the same purpose and beneficial effects as the first embodiment described above. It should be noted that in other embodiments, the same effect can also be achieved by setting only one force sensor module 4.

[0051] See Figure 8 , 9 A third embodiment of the present invention is similar to the first embodiment, except that:

[0052] The mounting hole 912 of the mounting platform 91 has a large diameter section 913 and a small diameter section 914 arranged in opposite directions, and the bearing part 311 and the flange part 312 are respectively located in the small diameter section 914 and the large diameter section 913.

[0053] The ball screw capable of feedback of force status includes a force sensor module 4, which includes four force sensing elements 41 and a collar 42 arranged around the axis L. The force sensing elements 41 are disposed inside the collar 42. The collar 42 is sleeved on the outside of the flange portion 312 to abut against the base 911 adjacent to the large diameter section 913. The mounting groove 5 is located on the side of the collar 42 adjacent to the flange portion 312. The force sensing elements 41 are respectively housed in the mounting groove 5 and are connected to the collar 42 at angular intervals around the axis L and abut against the flange portion 312.

[0054] The number of mounting slots 5 is four, and the mounting slots 5 are arranged at angular intervals around the axis L to accommodate the force sensing element 41 respectively. In this embodiment, the collar 42 and the flange 312 are locked together by threads, but this is not a limitation, and any connection method that can achieve the connection between the collar 42 and the flange 312 can be applied to this case.

[0055] In use, the force applied by the mounting platform 91 to the nut seat 3 is applied to the force sensing element 41 through the collar 42.

[0056] Thus, the third embodiment can also achieve the same purpose and beneficial effects as the first embodiment described above.

[0057] See Figure 10 , 11 A fourth embodiment of the present invention is similar to the first embodiment, except that:

[0058] The mounting platform 91 also includes six screw-locking members 915 screwed onto the base 911. Each screw-locking member 915 has a head 916 and a rod 917 connected to the head 916 for screwing onto the base 911.

[0059] The mounting groove 5 is located on the side of the flange portion 312 opposite to the bearing portion 311 along the extension direction of the axis L. The force sensor module 4 is respectively housed in the mounting groove 5 and connected to the flange portion 312, so that the screw 915 passes through the mounting groove 5 and the force sensor module 4 respectively to be screwed onto the base 911.

[0060] The ball screw capable of feedback of force state also includes six through slots 6 located on one side of the flange portion 312 adjacent to the bearing portion 311 along the extension direction of the axis L and respectively connected to the mounting groove 5.

[0061] The force sensor module 4 is annular, and the diameter of the through slot 6 is smaller than the diameter of the mounting slot 5. The mounting slots 5 are arranged at angular intervals around the axis L to accommodate the force sensor module 4 respectively. The head 916 of each screw 915 corresponds to its respective mounting slot 5 and abuts against its respective force sensor module 4. The rod 917 of each screw 915 passes through the force sensor module 4 and its respective through slot 6 to be fixed to the base 911.

[0062] In use, the force applied by the mounting platform 91 to the nut seat 3 will be applied to the force sensor module 4 by the screw locking member 915.

[0063] Thus, the fourth embodiment can also achieve the same purpose and beneficial effects as the first embodiment. It should be noted that in other embodiments, the same effect can be achieved by setting only one force sensor module 4.

[0064] In summary, by providing the mounting groove 5 and the force sensor module 4 in the nut seat 3, the force applied by the mounting platform 91 to the nut seat 3 can be measured, thereby improving the accuracy of use and enabling the determination of the offset of the screw shaft 2. Furthermore, since the nut seat 3 is a single component, its rigidity is not compromised, thus achieving the objective of this invention.

Claims

1. A ball screw capable of providing feedback on its applied force, applied to a mounting platform, the mounting platform including a mounting hole, the ball screw capable of providing feedback on its applied force comprising a screw shaft, the screw shaft including a rod extending along an axis, and a guide groove formed in the rod in a helical manner around the axis, characterized in that: The ball screw capable of providing feedback on force status further includes a nut seat and at least one force sensor module. The nut seat includes a base rotatably fitted around the rod body for mounting on the mounting platform. The base has a support portion passing through the mounting hole and used to support the mounting platform. The at least one force sensor module is connected to the nut seat and adapted to abut against the mounting platform to measure the force applied by the mounting platform to the nut seat. The ball screw capable of providing feedback on force status further includes at least one mounting groove located in the nut seat and used to accommodate the at least one force sensor module. The at least one mounting groove is located on one side of the support portion along the extension direction of the axis and on the side of the support portion away from the axis in a direction perpendicular to the axis. The at least one force sensor module is accommodated in the at least one mounting groove and connected to the support portion to abut against the mounting platform. The ball screw capable of providing feedback on force status can perform a detection process to determine the offset direction of the screw shaft.

2. The ball screw capable of feedback of force state according to claim 1, characterized in that: The ball screw capable of providing feedback on the applied force includes multiple force sensor modules and multiple mounting slots, which are arranged at angular intervals around the axis to accommodate the force sensor modules respectively.

3. The ball screw capable of feedback of force state according to claim 1, characterized in that: In the aforementioned detection process, the mounting platform is mounted on a slide group, which has two slide rails and a slide base movably mounted on the slide rails and connected to the mounting platform. The nut base is driven by the screw shaft to move along the axis and move the mounting platform along the slide rails to a first position. A controller electrically connected to the at least one force sensor module records the force measured at the first position as a first force information. Then, the nut base is moved to a second position, and the controller records the force measured at the second position as a second force information. The controller determines the offset direction of the screw shaft based on the magnitudes of the first and second force information. When the second force information is less than the first force information, it is determined that the screw shaft extends from the first position to the second position and is offset in a direction away from the force sensor module along the axis at the second position. When the second force information is greater than the first force information, it is determined that the screw shaft extends from the first position to the second position and is offset in a direction adjacent to the force sensor module along the axis at the second position.

4. A ball screw capable of providing feedback on its applied force, applied to a mounting platform, the ball screw comprising a screw shaft, the screw shaft including a rod extending along an axis, and a guide groove formed in the rod in a helical manner around the axis, characterized in that: The ball screw capable of providing force feedback further includes a nut seat and a force sensor module. The nut seat includes a base rotatably fitted around the rod body for mounting on a mounting platform. The base has a support portion for supporting the mounting platform. The force sensor module is connected to the nut seat and is adapted to abut against the mounting platform to measure the force applied by the mounting platform to the nut seat. The mounting platform includes a base and a mounting hole through the base for the base body to pass through. The mounting hole has a large-diameter section and a small-diameter section arranged opposite to each other. The force sensor module includes a collar arranged around the axis and a plurality of collars connected to the collar. The ring contains force sensing elements arranged at angular intervals around the axis. The base also has a flange connecting the bearing portion along the extension direction of the axis. The bearing portion and the flange are located in the small diameter section and the large diameter section, respectively. The outer contour of the flange in a section perpendicular to the axis is larger than the outer contour of the bearing portion in a section perpendicular to the axis. A collar is fitted on the outside of the flange to abut against the base adjacent to the large diameter section. The force sensing elements abut against the flange. The collar and the flange are locked together by threads. The ball screw capable of feedback of force status can perform a detection process to determine the offset direction of the screw shaft.

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