A linear motion device integrated with a force sensor

Abstract

The present invention relates to the technical field of motors, and specifically provides a linear motion device integrated with a force sensor, including: a housing, on which a connector connected to an external controller is provided; a sliding mechanism, a motion mechanism, a linear motor, an output shaft, a force sensor, and a position encoder disposed in the housing. Among them, a power circuit board is provided on the motion mechanism. The force sensor is connected to the power circuit board through a first cable, the power circuit board is connected to the connector through a second cable, and the position encoder is connected to the connector through a third cable; a hollow cavity for installing the first cable is provided inside the output shaft. The output shaft includes a first end fixed to the motion mechanism and a second end connected to the force sensor. The first cable enters the hollow cavity from the second end and exits from the first end to connect to the power circuit board. By the above method, the present invention can improve the force control accuracy of the motor and eliminate the problem of output force value drift during the use of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and more particularly to a linear motion device integrated with a force sensor. Background Art

[0002] At present, the force control of linear motors is generally achieved through current closed-loop control based on the detection of current changes in the motor. After long-term use, the force control accuracy of the motor decreases, and the problem of output force value drift is likely to occur during use. Therefore, recalibration and calibration are required. In addition, the force control accuracy range is limited by the current sampling accuracy and the design and technology of the motor. Summary of the Invention

[0003] The present invention provides a linear motion device integrated with a force sensor, which can improve the force control accuracy of the motor and eliminate the problem of output force value drift during the use of the motor.

[0004] To solve the above technical problems, one technical solution adopted by the present invention is: to provide a linear motion device integrated with a force sensor, including:

[0005] A housing, on which a connector connected to an external controller is provided;

[0006] A sliding mechanism fixed in the housing, a motion mechanism connected to the sliding mechanism, a linear motor connected to the motion mechanism, an output shaft provided on the motion mechanism, a force sensor provided on the output shaft, and a position encoder fixed on the housing. A power circuit board is provided on the motion mechanism. The force sensor is connected to the power circuit board through a first cable, the power circuit board is connected to the connector through a second cable, and the position encoder is connected to the connector through a third cable;

[0007] A hollow cavity for installing the first cable is provided inside the output shaft. The output shaft includes a first end fixed to the motion mechanism and a second end connected to the force sensor. The first cable enters the hollow cavity from the second end and exits from the first end to connect to the power circuit board;

[0008] The external controller collects the input current and input voltage of the position encoder to measure the displacement of the output shaft during linear motion, and at the same time collects the measured value of the force sensor to adjust the output force value of the output shaft in real time.

[0009] According to an embodiment of the present invention, an internal thread is provided at the end of the second end. The force sensor includes a body portion and a connecting portion connecting the body portion and the first cable. The connecting portion is provided with an external thread that mates with the internal thread.

[0010] According to an embodiment of the present invention, the first end is provided with a wire outlet hole communicating with the hollow cavity. The first cable includes a horizontal portion received in the hollow cavity and connected to the connecting portion, a vertical portion exposed from the output shaft and connected to the power circuit board, and a bending portion connecting the horizontal portion and the vertical portion and fixed to the wire outlet hole.

[0011] According to an embodiment of the present invention, the sliding mechanism includes a guide rail fixed on the housing and a slider slidably connected to the guide rail, and the moving mechanism is fixedly connected to the slider.

[0012] According to an embodiment of the present invention, the linear motor includes a mover skeleton fixedly connected to the moving mechanism and a stator fixedly connected to the housing. The mover skeleton is provided with a coil winding fixedly connected to the power circuit board. The stator includes a stator core and a magnet. The external controller controls the input current and input voltage of the coil winding through the power circuit board, so that the coil winding generates an Ampere force tangent to the magnet, pushing the moving mechanism to drive the slider to move linearly on the guide rail, thereby driving the output shaft to move linearly.

[0013] According to an embodiment of the present invention, the moving mechanism includes a first main body portion, a second main body portion, and a protruding portion located between the first main body portion and the second main body portion. The protruding portion is provided with a first through hole for fixing the output shaft and a second through hole for passing through the first cable.

[0014] According to an embodiment of the present invention, a plurality of first mounting holes for connecting the slider are provided through the first main body portion and the second main body portion. The first main body portion is further provided with a second mounting hole for connecting the power circuit board. Both ends of the first main body portion extend away from the first main body portion to form fixing portions, and the fixing portions are connected to the mover skeleton.

[0015] According to an embodiment of the present invention, the mover skeleton includes a winding portion for winding the coil winding and limiting portions located at both ends of the winding portion. The limiting portions are provided with first screw holes and positioning columns. The fixing portions are provided with second screw holes corresponding to the first screw holes and positioning grooves for installing the positioning columns.

[0016] According to an embodiment of the present invention, the housing includes a bottom wall and side walls surrounding the bottom wall. The bottom wall is provided with a receiving portion, a first mounting portion on one side of the receiving portion, a second mounting portion on the other side of the receiving portion, and a third mounting portion at an end near the second mounting portion. The side wall is provided with a fourth mounting portion. The receiving portion is used to receive the second cable. The first mounting portion is used to mount the stator. The second mounting portion is used to mount the guide rail. A limiting block for restricting the movement stroke of the slider is mounted on the third mounting portion. The position encoder is fixed to the fourth mounting portion.

[0017] According to an embodiment of the present invention, first grooves and second grooves are respectively formed on two opposite side walls of the housing. The first groove is used to mount the connector. An axle support frame is provided on the second groove. The output shaft passes through the housing through the axle support frame.

[0018] The beneficial effect of the present invention is that the real force value at the shaft end of the output shaft is measured in real time by the force sensor to adjust the output force value of the output shaft. Compared with the traditional motor based on current closed-loop control, the force control accuracy of the linear motion device of the present invention is not limited by the current sampling accuracy. The real force value is used as the force control reference object in real time, thereby improving the force control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 is an exploded structural schematic diagram of the linear motion device with an integrated force sensor according to an embodiment of the present invention;

[0021] Figure 2 is a front view of the linear motion device with an integrated force sensor according to an embodiment of the present invention;

[0022] Figure 3 is Figure 2 a sectional view along line A-A;

[0023] Figure 4 is a partial exploded structural schematic diagram of the linear motion device with an integrated force sensor according to an embodiment of the present invention;

[0024] Figure 5 is a structural schematic diagram of the housing according to an embodiment of the present invention;

[0025] Figure 6It is a schematic structural diagram of the motion mechanism according to an embodiment of the present invention;

[0026] Figure 7 It is a top view of the motion mechanism according to an embodiment of the present invention;

[0027] Figure 8 It is a schematic structural diagram of the mover skeleton according to an embodiment of the present invention. Detailed implementation manners

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0029] The terms "first", "second", and "third" in the present invention are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", and "third" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined. All directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0030] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0031] Figure 1 It is an exploded structural diagram of the linear motion device of the integrated force sensor according to an embodiment of the present invention, Figure 2 It is a front view of the linear motion device of the integrated force sensor according to an embodiment of the present invention. Please refer to Figure 1 and Figure 2, the linear motion device 100 includes a housing 10, a sliding mechanism 20 fixed in the housing 10, a motion mechanism 30 connected to the sliding mechanism 20, a linear motor 40 connected to the motion mechanism 30, an output shaft 50 provided on the motion mechanism 30, a force sensor 60 provided on the output shaft 50, and a position encoder 70 fixed on the housing 10.

[0032] Among them, please refer to Figure 1 and Figure 2 , a connector 80 connected to an external controller is provided on the housing 10, please refer to Figure 2 and Figure 3 , a power circuit board 90 is provided on the motion mechanism 30. The force sensor 60 is connected to the power circuit board 90 through a first cable 1, the power circuit board 90 is connected to the connector 80 through a second cable 2, and the position encoder 70 is connected to the connector 80 through a third cable 3. In this embodiment, the external controller collects the input current and input voltage of the position encoder 70 to measure the displacement of the output shaft 50 moving linearly, and at the same time collects the measured value of the force sensor 60 to adjust the output force value of the output shaft 50 in real time.

[0033] Furthermore, please refer to Figures 1 to 4 , a hollow cavity 51 for installing the first cable 1 is provided inside the output shaft 50. The output shaft 50 includes a first end 52 fixed on the motion mechanism 30 and a second end 53 connected to the force sensor 60. The first end 52 is provided with an outlet hole 521 communicating with the hollow cavity 51. The first cable 1 enters the hollow cavity 51 from the second end 53 and passes out through the outlet hole 521 to connect to the power circuit board 90.

[0034] Furthermore, please refer to Figure 3 and Figure 4 , the end of the second end 53 is provided with an internal thread. The force sensor 60 includes a body portion 61 and a connecting portion 62 connecting the body portion 61 and the first cable 1. The connecting portion 62 is provided with an external thread matching the internal thread. The second end 53 of the output shaft 50 is threadedly connected to the force sensor 60 through the connecting portion 62, which is convenient for installation, disassembly and operation and maintenance.

[0035] Furthermore, please refer to Figure 3 and Figure 4 , the first cable 1 includes a horizontal portion 101 housed in the hollow cavity 51 and connected to the connecting portion 62, a vertical portion 102 exposed outside the output shaft 50 and connected to the power circuit board 90, and a bending portion 103 connecting the horizontal portion 101 and the vertical portion 102 and fixed to the outlet hole 521.

[0036] Please refer to Figure 1 , the sliding mechanism 20 includes a guide rail 21 fixed on the housing 10 and a slider 22 slidably connected to the guide rail 21. The motion mechanism 30 is fixedly connected to the slider 22.

[0037] Please refer to Figure 1 , the linear motor 40 includes a mover skeleton 41 fixedly connected to the moving mechanism 30 and a stator 42 fixedly connected to the housing 10. A coil winding 43 fixedly connected to the power circuit board 90 is provided on the mover skeleton 41. The stator 42 includes a stator core 421 and a magnet 422. The mover skeleton 41 is located between the magnets 422 and the stator core 421 passes through the center of the mover skeleton 41.

[0038] The external controller controls the input current and input voltage of the coil winding 43 through the power circuit board 90, so that the coil winding 43 generates an Ampere force tangent to the magnet 422, pushing the moving mechanism 30 to drive the slider 22 to move linearly on the guide rail 21, thereby driving the output shaft 50 to move linearly.

[0039] Please refer to Figure 1 and Figure 5 , the housing 10 includes a bottom wall 11 and side walls 12 surrounding the bottom wall 11. First grooves 13 and second grooves 14 are respectively formed on two opposite side walls 12 of the housing 10. The first groove 13 is used to install the connector 80, and a shaft support frame 15 is provided on the second groove 14. The output shaft 50 passes through the housing 10 through the shaft support frame 15.

[0040] Please refer to Figure 5 , a receiving portion 111, a first mounting portion 112 on one side of the receiving portion 111, a second mounting portion 113 on the other side of the receiving portion 111, and a third mounting portion 114 provided at an end close to the second mounting portion 113 are provided on the bottom wall 11 of the housing 10. The receiving portion 111 is used to accommodate the second cable 2. During the process of the moving mechanism 30 driving the power circuit board 90 to move linearly, the second cable 2 folds and extends in the receiving portion 111, preventing the second cable 2 from being exposed outside and interfering with the movement process of the linear motion device 100. The first mounting portion 112 is used to mount the stator 42, the second mounting portion 113 is used to mount the guide rail 21, and a limit block 16 is mounted on the third mounting portion 114. The limit block 16 is used to limit the movement stroke of the slider 22, thereby limiting the movable stroke of the entire linear motion device 100, so as to prevent the mover skeleton 41 from colliding with the stator 42 and causing fracture when the position encoder 70 fails during the operation of the linear motion device 100.

[0041] Please refer to Figure 5 , a fourth mounting portion 121 is further provided on the inner side of the upper side wall 12 of the housing 10, and the position encoder 70 is fixed on the fourth mounting portion 121.

[0042] The internal arrangement of the housing 10 in this embodiment can make the structure of the entire linear motion device 100 more compact, reduce the volume of the entire linear motion device 100, and is conducive to the miniaturization and simplified control of the linear motion device 100.

[0043] Please refer to Figure 1 、 Figure 3 、 Figure 6 and Figure 7 ., the motion mechanism 30 includes a first main body portion 31, a second main body portion 32, and a convex portion 33 located between the first main body portion 31 and the second main body portion 32. The convex portion 33 is provided with a first through hole 331 for fixing the output shaft 50 and a second through hole 332 for passing through the first cable 1. A plurality of first mounting holes 311 for connecting the slider 22 are provided through the first main body portion 31 and the second main body portion 32. Preferably, four first mounting holes 311 are provided, with two provided on each of the first main body portion 31 and the second main body portion 32. The slider 22 is screwed to the motion mechanism 30 through the first mounting holes 311 to ensure that the output shaft 50 fixed to the motion mechanism 30 can move stably in a horizontal straight line. The first main body portion 31 is further provided with a second mounting hole 312 for connecting the power circuit board 90. Both ends of the first main body portion 31 extend away from the first main body portion 31 to form fixing portions 34, and the fixing portions 34 are connected to the mover skeleton 41.

[0044] Further, please refer to Figure 8 ., the mover skeleton 41 includes a winding portion 411 for winding the coil winding 43 and limiting portions 412 located at both ends of the winding portion 411. The limiting portions 412 are provided with first screw holes 4121 and positioning posts 4122. Please refer to Figure 6 ., the fixing portion 34 is provided with a second screw hole 341 corresponding to the first screw hole 4121 and a positioning groove 342 for installing the positioning post 4122. During installation, the positioning post 4122 is abutted against the positioning groove 342 and the screw sequentially passes through the first screw hole 4121 and the second screw hole 341 to fix the mover skeleton 41 and the motion mechanism 30.

[0045] The linear motion device 100 in this embodiment adjusts the output force value of the output shaft 50 by using the force sensor 60 to measure the real force value at the shaft end of the output shaft 50 in real time. Compared with the traditional motor based on current closed-loop control, the motor force control accuracy of the linear motion device 100 of the present invention is not limited by the current sampling accuracy, and the real force value is used as the force control reference object in real time, thereby improving the force control accuracy.

[0046] The above are only some embodiments of the present invention, and thus do not limit the protection scope of the present invention. Any equivalent device or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall similarly be included in the patent protection scope of the present invention.

Claims

1. A linear motion device integrated with a force sensor, characterized in that, Comprising: A housing, on which a connector for connecting to an external controller is provided; A sliding mechanism fixed in the housing, a motion mechanism connected to the sliding mechanism, a linear motor connected to the motion mechanism, an output shaft provided on the motion mechanism, a force sensor provided on the output shaft, and a position encoder fixed on the housing. A power circuit board is provided on the motion mechanism. The force sensor is connected to the power circuit board through a first cable, the power circuit board is connected to the connector through a second cable, and the position encoder is connected to the connector through a third cable; A hollow cavity for installing the first cable is provided inside the output shaft. The output shaft includes a first end fixed on the motion mechanism and a second end connected to the force sensor. The first cable enters the hollow cavity from the second end and exits from the first end to connect to the power circuit board; The external controller collects the input current and input voltage of the position encoder to measure the displacement of the output shaft during linear motion, and at the same time collects the measured value of the force sensor to adjust the output force value of the output shaft in real time.

2. The linear motion device according to claim 1, characterized in that, The end of the second end is provided with an internal thread. The force sensor includes a body part and a connecting part connecting the body part and the first cable. The connecting part is provided with an external thread matching the internal thread.

3. The linear motion device according to claim 2, wherein The first end is provided with an outlet hole communicating with the hollow cavity. The first cable includes a horizontal part received in the hollow cavity and connected to the connecting part, a vertical part exposed outside the output shaft and connected to the power circuit board, and a bending part connecting the horizontal part and the vertical part and fixed in the outlet hole.

4. The linear motion device according to claim 1, wherein, The sliding mechanism includes a guide rail fixed on the housing and a slider slidably connected to the guide rail. The motion mechanism is fixedly connected to the slider.

5. The linear motion device according to claim 4, characterized in that, The linear motor includes a mover skeleton fixedly connected to the motion mechanism and a stator fixedly connected to the housing. A coil winding fixedly connected to the power circuit board is provided on the mover skeleton. The stator includes a stator core and a magnet. The external controller controls the input current and input voltage of the coil winding through the power circuit board, so that the coil winding generates an Ampere force tangent to the magnet, pushing the motion mechanism to drive the slider to perform linear motion on the guide rail, thereby driving the output shaft to perform linear motion.

6. The linear motion device according to claim 5, wherein, The motion mechanism includes a first main body part, a second main body part, and a convex part located between the first main body part and the second main body part. A first through hole for fixing the output shaft and a second through hole for passing the first cable are provided on the convex part.

7. The linear motion device according to claim 6, characterized in that, A plurality of first mounting holes for connecting the slider are provided through the first main body part and the second main body part. A second mounting hole for connecting the power circuit board is further provided on the first main body part. Fixing parts are respectively formed at both ends of the first main body part extending away from the first main body part, and the fixing parts are connected to the mover skeleton.

8. The linear motion device according to claim 7, characterized in that, The mover skeleton includes a winding portion for winding the coil winding and limiting portions located at both ends of the winding portion. The limiting portions are provided with first screw holes and positioning posts, and the fixing portion is provided with second screw holes corresponding to the first screw holes and positioning grooves for installing the positioning posts.

9. The linear motion device according to claim 5, wherein, The housing includes a bottom wall and side walls surrounding the bottom wall. The bottom wall is provided with a receiving portion, a first mounting portion on one side of the receiving portion, a second mounting portion on the other side of the receiving portion, and a third mounting portion at an end near the second mounting portion. The side walls are provided with a fourth mounting portion. The receiving portion is used for receiving the second cable. The first mounting portion is used for mounting the stator. The second mounting portion is used for mounting the guide rail. The third mounting portion is provided with a limiting block for limiting the movement stroke of the slider. The position encoder is fixed to the fourth mounting portion.

10. The linear motion device according to claim 9, characterized in that, First grooves and second grooves are respectively formed in two opposite side walls of the housing. The first groove is used for mounting the connector, and the second groove is provided with a shaft support frame. The output shaft passes through the housing through the shaft support frame.

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