Linear actuator and linear driving method thereof

Abstract

The invention discloses a linear driver which comprises a semi-circular-arc-shaped rack and a driving sliding base limited on the semi-circular-arc-shaped rack in a sliding mode, and a plurality of layers of driving swing plates meshed with the semi-circular-arc-shaped rack are arranged on the driving sliding base. A plurality of layers of second arc teeth are arranged on the side face of the semi-arc-shaped rack, and first arc teeth meshed with the corresponding second arc teeth are arranged on the side face of the driving swing plate. A crankshaft is rotationally connected to the driving sliding seat, and an eccentric disc is eccentrically arranged on the crankshaft; the driving swing plate is in transmission connection with the eccentric disc through the needle bearing, and the crankshaft is in transmission connection with the transmission mechanism. The eccentric disc is driven by the transmission mechanism to rotate, so that the first arc teeth of the driving swing plate are driven to be engaged with the tooth surfaces of the second arc teeth on the semi-circular-arc-shaped rack for displacement. According to the linear driver and the linear driving method thereof, driving is achieved on the basis of circumferential swing of an eccentric structure, and the linear driver is matched with a robot joint in the start-stop stage or during load sudden change.

Description

Technical Field

[0001] This invention relates to the field of robot joint technology, and more specifically to a linear actuator and its linear driving method. Background Technology

[0002] In robot joint mechanisms, a linear actuator is an execution device that converts input energy into linear motion output. Its core function is to drive robot joints directly or indirectly to achieve linear displacement, force, or torque output, thereby controlling the flexion, extension, and retraction of the joints. It is a key component for power transmission and motion control of robot joints.

[0003] In robot control, the most common source of power for movement is the motor. For high-precision control, servo motors are currently the primary power source for joint movement. However, the power output of a motor is rotational force. How to efficiently convert this force into linear driving force has corresponding structural requirements in different robot design scenarios. Traditional technology directly uses gears to drive racks to achieve linear drive. During start-up and shutdown or sudden load changes, the motion is not smooth and is prone to instantaneous impact. Furthermore, existing actuators that convert rotational drive to linear drive lack linear and curvilinear motion feedback, making it difficult to achieve closed-loop control and resulting in low accuracy. Summary of the Invention

[0004] This invention overcomes the shortcomings of the prior art and provides a linear actuator and its linear driving method, which realizes driving based on the eccentric structure circular oscillation, and is adapted to robot joints during start-stop phases or sudden load changes.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a linear actuator, comprising: a semi-circular arc-shaped rack, and a drive slide slidably defined on the semi-circular arc-shaped rack, wherein the drive slide is provided with a plurality of drive swing plates meshing with the semi-circular arc-shaped rack; the side of the semi-circular arc-shaped rack is provided with a plurality of second arc teeth, and the side of the drive swing plates is provided with first arc teeth meshing with the corresponding second arc teeth; a crankshaft is rotatably connected to the drive slide, and an eccentric disk is eccentrically disposed on the crankshaft; the drive swing plates are driven to be connected to the eccentric disk via needle roller bearings, and the crankshaft is driven to be connected to a transmission mechanism; the transmission mechanism drives the eccentric disk to rotate, thereby causing the first arc teeth of the drive swing plates to engage with the second arc teeth on the semi-circular arc-shaped rack.

[0006] In a preferred embodiment of the present invention, the transmission mechanism includes an input motor mounted on a drive slide, an input gear connected to the input motor, and a driven gear connected to the crankshaft that is connected to the input gear. The rotation of the input gear drives the meshing driven gear to rotate, thereby driving the crankshaft to rotate the eccentric disk.

[0007] In a preferred embodiment of the present invention, the drive slide includes a housing base plate and a drive housing that are mated together. A groove is provided on the upper side and / or lower side of the semi-circular arc-shaped rack. The housing base plate and / or the upper drive housing are provided with rack limiting clamps that are slidably limited in the groove.

[0008] In a preferred embodiment of the present invention, an eccentric disc is eccentrically sleeved on the crankshaft. The crankshaft is also provided with a gear keyway that meshes with the driven gear; Furthermore, the crankshaft is rotatably connected to the upper drive housing and the housing base plate respectively via tapered roller bearings, and the crankshaft rotates to be confined within the drive slide via tapered roller bearings.

[0009] In a preferred embodiment of the present invention, a triboelectric patch is provided on the side of the semi-circular rack along the driving displacement trajectory, and an annular friction patch is provided on the annular side of the driven gear to contact the triboelectric patch. A friction mover is also provided on the bottom plate of the housing. By the contact between the triboelectric patch and the friction mover, the linear displacement of the semi-circular rack can be monitored to capture the linear position change of the joint and convert the mechanical displacement into an electrical signal.

[0010] In a preferred embodiment of the present invention, a friction washer ring is further included, wherein the friction washer ring is disposed between the tapered roller bearing and the needle roller bearing; And / or, the triboelectric actuator comprises several layers of polyimide film, copper electrode, sponge rubber and aluminum alloy substrate stacked on each other, with the sponge rubber used to ensure full contact between the triboelectric actuator and the triboelectric patch; And / or, the sides of the second arc teeth of adjacent layers are symmetrically spliced; And / or, the sides of the first arc teeth of adjacent drive plates are symmetrically spliced.

[0011] In a preferred embodiment of the present invention, an annular mating mover is fixedly installed on the inner surface of the base plate of the housing; an annular friction patch contacts the annular mating mover to monitor the curved displacement of the crankshaft. When the driven gear rotates, the annular friction patch can rotate relative to the annular mating mover to achieve detection.

[0012] In a preferred embodiment of the present invention, the model equation of the first arc tooth is as follows: The equation of the baseline cycloid: ; Equation of the equidistant curve: ; Three-dimensional draft tension equation: ; Scaling factor: ; 3D coordinates: ; Where t is a parameter variable, representing an independent parameter in the equation, and its range is... , where n is a positive integer, and t is used to describe the periodic change of the cycloid in the circumferential direction; L is the total length parameter of the cycloid, used for calculating the linear part in the x-direction of the reference cycloid equation; n is a parameter representing the number of periods, which determines the total number of periods of the cycloid and is related to the range of values ​​for t. R is the base circle radius parameter, which is the core geometric parameter of the cycloid and rack tooth profile, affecting the curvature and tooth size of the cycloid; Let be the coordinate function of the reference cycloid of the first arc tooth in the x-direction. Let be the coordinate function of the reference cycloid of the first arc tooth in the y-direction; Let be the coordinate function of the equidistant curve in the x-direction. y is the coordinate function of the equidistant curve in the y-direction; In the equation This is the modulus calculation term in the cycloidal normal direction, used to standardize the offset and ensure the uniformity of the equidistant curves.

[0013] In a preferred embodiment of the present invention, the model equation for the second arc tooth is as follows: The equation of the baseline cycloid: ; Add a circle at the periodic point t=2kπ: ; , ; The tooth profile equation after draft, with a scaling factor of: ; Three-dimensional equations: ; , , .

[0014] in, Let x be the coordinate function of the reference cycloid of the second arc tooth in the x-direction. Let be the coordinate function of the reference cycloid of the second arc tooth in the y-direction; t is a parameter variable, representing an independent parameter in the equation, and its range of values ​​is... , where n is a positive integer, and t is used to describe the periodic change of the cycloid in the circumferential direction; L is the total length parameter of the cycloid, used for calculating the linear part in the x-direction of the reference cycloid equation; n is a parameter representing the number of periods, which determines the total number of periods of the cycloid and is related to the range of values ​​for t. R is the base circle radius parameter, which is the core geometric parameter of the cycloid and rack tooth profile, affecting the curvature and tooth size of the cycloid; The coordinate function of the three-dimensional draft stretch in the z-direction, relative to the x-coordinate of the reference cycloid. The linear correlation is determined by the total height H and the total length L of the cycloid, i.e., its slope. ; H is the total height parameter of the three-dimensional structure, used to control the height range of draft stretching; α is the draft angle parameter, which affects the rate of change of the scaling factor and determines the degree of tilt of the three-dimensional structure in the height direction; For scaling factor function, as It changes with the form, and is used to achieve the draft and scaling effect of three-dimensional structures; , , Let be the final three-dimensional coordinate function, representing the coordinates in the x, y, and z directions in three-dimensional space, respectively. and It is obtained by multiplying the coordinates of the equidistant curve by the scaling factor. Directly equal to draft stretch ; k is the periodic point index parameter, used to identify the position where circles are added to the rack tooth profile; This is the angle parameter of the circle, used to describe the circumferential coordinates of the added circle; Add a coordinate function of the circle in the x-direction at the periodic point, consisting of the periodic position 6kπ and the horizontal component of the circle. composition; Add a coordinate function of the circle in the y-direction at the periodic point, consisting of a constant term 1 and the perpendicular component of the circle. composition; The scaling factor function for the tooth draft varies with z. , used to adjust the dimensions of the tooth profile in the height direction; , , Let X and Y be the final three-dimensional coordinate functions of the tooth profile, corresponding to the coordinates in the x, y, and z directions, respectively, where X and Y are determined by the tooth profile's basic coordinates and a scaling factor. Multiplying them together, we get Z, which is directly equal to the height parameter z.

[0015] In a preferred embodiment of the present invention, a linear driving method for a linear actuator is provided, which is implemented using a linear actuator and includes the following steps: The crankshaft is driven to rotate by the transmission mechanism, which in turn drives the eccentric rotation of the eccentric disk to the drive swing plate through the rolling friction of the needle roller bearing. Two sets of crankshafts and two sets of drive swing plates are symmetrically arranged on the second arc tooth of the semi-circular rack to form a symmetrical driving force, which is used to counteract the eccentric load caused by unilateral force and avoid the swaying of the rack during linear motion. The circumferential oscillation of the drive swing plate is converted into the linear motion of the rack through arc tooth meshing. The arc tooth meshing process is a progressive contact, realizing the linear drive of the linear actuator.

[0016] This invention addresses the deficiencies in the technical background, and the beneficial technical effects of this invention are: This invention discloses a linear actuator and its linear driving method, which achieves driving based on the eccentric structure's circumferential oscillation, and is adapted to robot joints during start-stop phases or sudden load changes.

[0017] 1. Compared with the method of directly driving the rack by gears, the present invention has higher motion stability and less impact vibration. The eccentric rotation of the eccentric disk is transmitted to the drive swing plate through the rolling friction of the needle roller bearing. The rolling friction coefficient is much smaller than the sliding friction of gear meshing, which reduces friction fluctuations during the motion. The two sets of crankshafts and the two sets of drive swing plates are symmetrically arranged to form a symmetrical driving force, which can offset the eccentric load caused by unilateral force and avoid the swaying of the rack during linear motion.

[0018] 2. In this invention, the circumferential oscillation of the swing plate is converted into the linear motion of the rack through the meshing of the arc teeth. The meshing process of the arc teeth is a progressive contact, which results in less impact and smoother movement compared to the instantaneous rigid contact of the straight teeth.

[0019] 3. This invention, in conjunction with a triboelectric sensor and a triboelectric patch mounted on the crankshaft, can achieve linear and curvilinear motion feedback respectively, enabling closed-loop control of robot joints and improving the accuracy of robot movements. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a schematic diagram of the overall structure assembly of a preferred embodiment of the present invention; Figure 2 This is a bottom view of the overall structural assembly of a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of the structure after the drive housing is removed in a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the internal structure of the linear actuator according to a preferred embodiment of the present invention; Figure 5 This is an exploded view of the internal structure of the linear actuator according to a preferred embodiment of the present invention; Figure 6This is an exploded structural diagram of the crankshaft according to a preferred embodiment of the present invention; Figure 7 This is a schematic diagram of the crankshaft structure according to a preferred embodiment of the present invention; Figure 8 This is a schematic diagram of the driven gear structure of a preferred embodiment of the present invention; Figure 9 This is a schematic diagram of the position of the annular mating mover in a preferred embodiment of the present invention; Figure 10 This is a schematic diagram showing the position of the triboelectric patch in a preferred embodiment of the present invention; Figure 11 This is a schematic diagram of the friction actuator principle of a preferred embodiment of the present invention.

[0022] In the diagram, 1. Crankshaft; 2. Eccentric disk; 3. Needle roller bearing; 4. Drive plate; 5. Swinging mating hole; 6. Semi-circular rack; 7. Driven gear; 8. Input gear; 9. Input motor; 401. First arc tooth; 601. Second arc tooth; 101. Gear keyway; 102. Tapered roller bearing; 402. Through enlarged hole; 10. Drive housing; 11. Housing base plate; 12. Rack limiting clamp; 13. Triboelectric patch; 1301. Friction mover; 14. Drive plate; 15. Friction washer ring; 901. Motor terminal; 16. Annular friction patch; 1601. Annular mating mover. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention and therefore only show the components relevant to the present invention.

[0024] It should be noted that if directional indicators (such as up, down, bottom, top, etc.) are involved in the embodiments of the present invention, these directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature. Unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0025] Example 1, as Figures 1-6 As shown, a linear actuator includes: a semi-circular rack 6, and a drive slide that is slidably defined on the semi-circular rack 6.

[0026] Specifically, the drive slide includes a base plate 11 and a drive housing 10 that are mated together. The side of the semi-circular arc-shaped rack 6 is provided with a sliding groove. The base plate 11 and the upper drive housing 10 are provided with rack limiting clamps 12 that are slidably limited in the sliding groove. The drive slide is provided with several layers of drive swing plates 4 that mesh with the semi-circular arc-shaped rack 6. The side of the semi-circular arc-shaped rack 6 is provided with several layers of second arc teeth 601. The side of the drive swing plate 4 is provided with first arc teeth 401 that mesh with the corresponding second arc teeth 601.

[0027] Furthermore, a crankshaft 1 is rotatably connected to the drive slide, and an eccentric disk 2 is eccentrically mounted on the crankshaft 1. The drive swing plate 4 is driven to the eccentric disk 2 via a needle roller bearing 3, and the crankshaft 1 is driven to the transmission mechanism. The transmission mechanism drives the eccentric disk 2 to rotate, thereby causing the first arc tooth 401 of the drive swing plate 4 to mesh with the second arc tooth 601 on the semi-circular arc rack 6. More specifically, the transmission mechanism includes an input motor 9 mounted on the drive slide, which is driven to the input gear 8. A driven gear 7 connected to the crankshaft 1 is driven to the input gear 8. The rotation of the input gear 8 drives the meshing driven gear 7 to rotate, thereby driving the crankshaft 1 to rotate the eccentric disk 2. An eccentric disc 2 is eccentrically fitted on the crankshaft 1, and a gear keyway 101 that meshes with the driven gear 7 is also provided on the crankshaft 1; and the crankshaft 1 is rotatably connected to the upper drive housing 10 and the housing base plate 11 respectively through tapered roller bearings 102, and a friction washer ring 15 is provided between the tapered roller bearings 102 and the needle roller bearings 3; the crankshaft 1 rotates through the tapered roller bearings 102 to be confined within the drive slide.

[0028] In Example 2, based on Example 1, a triboelectric pad 13 is provided on the side of the semi-circular rack 6 along the driving displacement trajectory. An annular friction pad 16 is provided on the annular side of the driven gear 7, which contacts the triboelectric pad 13. An annular mating mover 1601 is fixedly installed on the inner surface of the housing base plate 11. The contact between the annular friction pad 16 and the annular mating mover 1601 is used to monitor the curved displacement of the crankshaft 1. When the driven gear 7 rotates, the annular friction pad 16 can rotate relative to the annular mating mover 1601 to achieve detection.

[0029] In Example 3, based on Example 1 or Example 2, a friction actuator 1301 is further provided on the base plate 11 of the outer casing. The friction actuator 1301 contacts the triboelectric patch 13, enabling linear displacement monitoring of the semi-circular arc-shaped rack 6. This captures changes in the linear position of the joint and converts the mechanical displacement into an electrical signal. Furthermore, the friction actuator 1301 comprises several layers of polyimide film, copper electrodes, sponge rubber, and an aluminum alloy substrate stacked together. The sponge rubber ensures sufficient contact between the friction actuator 1301 and the triboelectric patch 13.

[0030] Example 4, based on Example 3, such as Figures 1-11 As shown, a linear actuator includes a crankshaft 1 and a pair of eccentric disks 2 respectively fixed on the crankshaft 1. The crankshaft 1 and the eccentric disks 2 are integrally machined using a CNC machine tool in the prior art. The eccentric disks 2 have a disc-shaped structure and are eccentrically positioned with respect to the crankshaft 1.

[0031] A needle roller bearing 3 is installed on the outside of the eccentric disk 2. The needle roller bearing 3 specifically includes a retaining ring and needle rollers. The number of needle rollers is set in several groups and is evenly distributed in a circumferential array. The retaining ring supports the needle rollers, maintains the circumferential distribution of the needle rollers, and enables the needle rollers to roll.

[0032] The linear actuator in this embodiment also includes a pair of drive swing plates 4, and a swing engagement hole 5 is formed through the drive swing plates 4. The eccentric disk 2 contacts the inner wall surface of the swing engagement hole 5 through a needle roller bearing 3. Figure 5 and Figure 6 As shown in the diagram, in this embodiment, there are two crankshafts 1, each with two sets of eccentric disks 2. Two sets of drive plates 4 are arranged vertically, corresponding to the eccentric disks 2 on the crankshafts 1. Furthermore, in this embodiment, the number of semi-circular racks 6 corresponds to the number of drive plates 4; two semi-circular racks 6 and two drive plates 4 are used. The large end of the second arc tooth 601 in the two semi-circular racks 6 faces outwards, and the small end is spliced ​​with the small end of the second arc tooth 601 of the adjacent semi-circular rack 6. The sides of the second arc teeth 601 in adjacent layers face each other, and the connection of the second arc teeth 601 in adjacent layers forms a tooth surface shape; the sides of the first arc teeth 401 in adjacent drive plates 4 face each other; that is, the second arc teeth 601 in adjacent layers are spliced ​​together in a supporting manner. However, this is not the only option. In other embodiments, the semi-circular rack 6 can be integrally formed, that is, the number of second arc teeth 601 on the semi-circular rack 6 matches the number of drive swing plates 4.

[0033] When crankshaft 1 rotates, it drives eccentric disk 2 to rotate eccentrically. Eccentric disk 2 engages with oscillating hole 5 via needle roller bearing 3, driving drive plate 4 to oscillate circumferentially. Figure 5 As shown, the linear actuator of the present invention also includes a semi-circular arc-shaped rack 6. A first arc tooth 401 is formed on the drive swing plate 4, and a second arc tooth 601 is formed on the semi-circular arc-shaped rack 6. When the drive swing plate 4 oscillates in a circular motion, the first arc tooth 401 and the second arc tooth 601 engage to drive the semi-circular arc-shaped rack 6 to move linearly. The width of the drive swing plate 4 is minimized to reduce the distance between the swing engagement hole 5 and the first arc tooth 401, thereby ensuring the stability of the drive.

[0034] In Example 5, based on Example 4, the linear actuator further includes a driven gear 7, an input gear 8, and an input motor 9, as shown below. Figure 6 As shown, a gear keyway 101 is provided on the outer surface of the crankshaft 1. The gear keyway 101 engages with the driven gear 7, allowing the driven gear 7 to be fixed to the end of the crankshaft 1 and drive the crankshaft 1 to rotate. The driven gear 7 meshes with the input gear 8, as shown... Figure 3 and Figure 4 As shown in the figure, the input gear 8 is driven to rotate by the input motor 9, which causes the input gear 8 to drive the driven gear 7 to rotate, thereby driving the crankshaft 1 to rotate.

[0035] At least two sets of tapered roller bearings 102 are fitted and installed on the outside of the crankshaft 1. The tapered roller bearings 102 can radially limit the crankshaft 1 during rotation. The tapered roller bearings 102 are positioned between the crankshaft 1 and the drive housing 10, preventing frictional contact between the crankshaft 1 and the drive housing 10. Specifically, as shown... Figure 7 As shown, the tapered roller bearing 102 includes an outer ring, an inner ring, and bearing rollers. The inner ring is located inside the outer ring and the two are coaxially aligned. Bearing rollers are arranged between the outer ring and the inner ring, and there are several groups of bearing rollers evenly distributed in a circumferential array.

[0036] like Figure 4 and Figure 5 As shown, a through-hole 402 is provided through the drive swing plate 4. The input motor 9 of the present invention passes through the through-hole 402. The diameter of the through-hole 402 is larger than the diameter of the input motor 9, so that there is a sufficient gap between the through-hole 402 and the input motor 9, thereby avoiding contact interference between the inner wall surface of the through-hole 402 and the outer surface of the input motor 9 when the drive swing plate 4 performs circumferential swinging activity.

[0037] like Figure 1As shown, the present invention also includes a drive housing 10 and a housing base plate 11, which together form a closed housing, thereby enclosing and protecting the crankshaft 1, drive swing plate 4, driven gear 7, and input gear 8 within. The drive housing 10 and housing base plate 11 are fixed together by screws, and the actuator of the present invention can be opened by disassembling the drive housing 10 and housing base plate 11.

[0038] A rack-and-tooth limiting clamping rib 12 is integrally machined and formed on both the drive housing 10 and the housing base plate 11, such as... Figure 1 and Figure 3 As shown, grooves are provided on the upper and lower surfaces of the semi-circular arc-shaped rack 6. The rack limiting clamp 12 cooperates with the grooves on the surface of the semi-circular arc-shaped rack 6 to limit the semi-circular arc-shaped rack 6, so that the semi-circular arc-shaped rack 6 can only move along its length direction.

[0039] The linear actuator of the present invention also includes a drive board 14. The input motor 9 is provided with a motor terminal 901. The drive board 14 is connected to the input motor 9 through the motor terminal 901, thereby enabling the drive board 14 to control the input motor 9. The drive board 14 converts the weak current control signal into strong current power output to achieve precise control of the input motor 9. A rotational angular displacement sensor is provided between the rotational shaft of the input motor 9 and the motor housing. The rotational angular displacement sensor includes a detection shaft and a potentiometer. The potentiometer is fixed to the motor housing, and the detection shaft is drivenly connected to the rotational shaft of the input motor 9. The potentiometer is a ring-shaped resistor. The brush contacts are fixed on the rotating shaft and come into contact with the resistor as the shaft rotates, converting the angle into an electrical signal. A fixed DC voltage is connected to both ends of the resistor. The position of the brush determines the ratio of the resistance value from the two ends of the resistor to the brush. For example, when rotating 0°, the brush is at one end of the resistor, and the output voltage is approximately 0V; when rotating 180°, the brush is in the middle, and the output voltage is approximately 2.5V; when rotating 360°, the output voltage is approximately 5V. The external controller calculates the corresponding rotation angle by measuring the voltage value output by the brush. The control accuracy of the input motor 9 is improved by using a rotational angular displacement sensor, so that the actual rotation angle of the input motor 9 can achieve a closed-loop feedback effect.

[0040] The drive housing 10 is provided with a slot, through which the input motor 9 can be locked and thus fixedly installed.

[0041] For monitoring the curved displacement of crankshaft 1: like Figure 3 and Figure 8As shown, an annular friction patch 16 is attached to the surface of the driven gear 7; an annular mating mover 1601 is fixedly installed on the lower surface of the housing base plate 11; the annular friction patch 16 contacts the annular mating mover 1601 to achieve curved displacement monitoring of the crankshaft 1. The annular mating mover 1601 is fixedly installed on the housing base plate 11. When the driven gear 7 rotates, the annular friction patch 16 can rotate relative to the annular mating mover 1601 to achieve detection. This position sensor is based on a grating structure with an independent layer triboelectric nanogenerator, utilizing the triboelectric effect. In this sensor, components such as the stator and rotor are made of different materials. When they come into contact with each other and move relative to each other, due to the different binding abilities of different materials for electrons, electrons will transfer from the surface of the material with weaker binding ability to the surface of the material with stronger binding ability, thereby causing the two material surfaces to carry equal amounts of opposite charges.

[0042] For example, during relative motion between stator electrodes and other components, triboelectric charging occurs on the electrode surface due to this effect. In a layered TENG structure, the relative motion between electrodes allows charge transfer. As the electrodes move, the charge distribution accumulated on their surfaces changes, altering the distribution of positive and negative charges and resulting in charge transfer. This charge transfer creates a potential difference between the electrodes, thereby generating an electrical signal.

[0043] The output voltage signal consists of three sets of voltage signals with a fixed phase difference. This multi-signal output method can provide richer position information. The principle is that in the sensor's structural design, by rationally arranging the electrodes and moving parts, the charge transfer between the electrodes differs under different positions or motion states, thus generating voltage signals with different characteristics. Different motion states cause changes in the amplitude and frequency of the output signal. For example, different rotor rotation speeds result in different relative speeds of the electrodes, affecting the rate and extent of charge transfer, ultimately reflected in the frequency change of the output signal. By detecting these changes in signal characteristics, information such as the rotation angle and angular velocity of crankshaft 1 can be sensed, achieving curved displacement monitoring.

[0044] like Figure 3 and Figure 4 As shown, a triboelectric patch 13 is attached to the surface of the semi-circular arc-shaped rack 6, and a friction mover 1301 is fixedly installed on the bottom plate 11 of the outer shell. Through the contact between the triboelectric patch 13 and the friction mover 1301, the linear displacement of the semi-circular arc-shaped rack 6 can be monitored. The linear position change of the joint can be captured in real time, and the mechanical displacement can be converted into an electrical signal for feedback to ensure that the joint moves accurately according to the preset trajectory.

[0045] The triboelectric actuator 1301 is composed of a polyimide film, a copper electrode, a sponge rubber, and an aluminum alloy substrate stacked on top of each other. The role of the sponge is to ensure that the triboelectric actuator 1301 is in full contact with the triboelectric patch 13.

[0046] The triboelectric patch 13 is a flexible circuit board with three-phase differential electrodes (A-Phase, B-Phase, C-Phase), which is printed on a substrate and finally attached to the surface of the semi-circular toothed rack 6.

[0047] When the triboelectric actuator 1301 moves linearly along the triboelectric patch 13, the polyimide film contacts and separates from the copper electrode of the triboelectric patch 13; in this embodiment, the polyimide film used is a Kapton film. Due to the difference in electronegativity between polyimide and copper, charge transfer occurs upon contact; upon separation, a variable capacitance is formed between the two, and the change in capacitance corresponds to the displacement.

[0048] The three-phase electrodes on the triboelectric patch 13 are offset from each other by 1 / 6 cycle. When the triboelectric mover 1301 slides, it will generate a three-phase electrical signal with a phase difference of π / 3. By analyzing the phase relationship and pulse number of these three sets of signals, the displacement magnitude and motion direction can be determined simultaneously.

[0049] like Figure 5 As shown, the linear actuator of the present invention also includes a friction washer ring 15. The friction washer ring 15 is provided between the tapered roller bearing 102 and the needle roller bearing 3, which makes the internal structure of the actuator of the present invention more compact and stable and reduces axial displacement.

[0050] Example 6, based on any one of Examples 1 to 5, such as Figures 1-4 As shown, in this embodiment, both the first arc tooth 401 and the second arc tooth 601 are conical arc teeth with an angle. The conical arc teeth have a backlash-eliminating effect, which can ensure that the positioning error is minimized. After backlash elimination, the meshing relationship of the bevel gear is more stable, and the trajectory deviation of each movement is smaller. Specifically: The model equation for the first arc tooth 401 is as follows: The equation of the baseline cycloid: ; Equation of the equidistant curve: ; Three-dimensional draft tension equation: ; Scaling factor: ; Final 3D coordinates: , .

[0051] The model equations for the second arc tooth 601 are as follows: The equation of the baseline cycloid: ; Add a circle at the periodic point t=2kπ: ; , ; The tooth profile equation after draft, with a scaling factor of: ; Three-dimensional equations: ; , , .

[0052] Above: t is a parameter variable, representing an independent parameter in the equation, with a range of values ​​of... , where n is a positive integer, and t is used to describe the periodic change of the cycloid in the circumferential direction; L is the total length parameter of the cycloid, used for calculating the linear part in the x-direction of the reference cycloid equation; n is a parameter representing the number of periods, which determines the total number of periods of the cycloid and is related to the range of values ​​for t. R is the base circle radius parameter, which is the core geometric parameter of the cycloid and rack tooth profile, affecting the curvature and tooth size of the cycloid; Let x be the coordinate function of the reference cycloid of the first arc tooth 401 in the x-direction. Let y be the coordinate function of the reference cycloid of the first arc tooth 401 in the y direction; Let x be the coordinate function of the reference cycloid of the second arc tooth 601 in the x-direction. Let y be the coordinate function of the reference cycloid of the second arc tooth 601 in the y direction; Let be the coordinate function of the equidistant curve in the x-direction. y is the coordinate function of the equidistant curve in the y-direction; In the equation This is the modulus calculation term in the cycloidal normal direction, used to standardize the offset and ensure the uniformity of the equidistant curves.

[0053] The coordinate function of the three-dimensional draft stretch in the z-direction, relative to the x-coordinate of the reference cycloid. The linear correlation is determined by the total height H and the total length L of the cycloid, i.e., its slope. ; H is the total height parameter of the three-dimensional structure, used to control the height range of draft stretching; α is the draft angle parameter, which affects the rate of change of the scaling factor and determines the degree of tilt of the three-dimensional structure in the height direction; For scaling factor function, as It changes with the form, and is used to achieve the draft and scaling effect of three-dimensional structures; , , Let be the final three-dimensional coordinate function, representing the coordinates in the x, y, and z directions in three-dimensional space, respectively. and It is obtained by multiplying the coordinates of the equidistant curve by the scaling factor. Directly equal to draft stretch ; k is the periodic point index parameter, used to identify the position where circles are added to the rack tooth profile; This is the angle parameter of the circle, used to describe the circumferential coordinates of the added circle; Add a coordinate function of the circle in the x-direction at the periodic point, consisting of the periodic position 6kπ and the horizontal component of the circle. composition; Add a coordinate function of the circle in the y-direction at the periodic point, consisting of a constant term 1 and the perpendicular component of the circle. composition; The scaling factor function for the tooth draft varies with z. , used to adjust the dimensions of the tooth profile in the height direction; , , Let X and Y be the final three-dimensional coordinate functions of the tooth profile, corresponding to the coordinates in the x, y, and z directions, respectively, where X and Y are determined by the tooth profile's basic coordinates and a scaling factor. Multiplying them together, we get Z, which is directly equal to the height parameter z.

[0054] Example 7: A linear driving method for a linear driver, implemented using a linear driver from any of Examples 1 to 6, the linear driving method comprising the following steps: The crankshaft 1 is driven to rotate by the transmission mechanism, which drives the eccentric rotation of the eccentric disk 2 to be transmitted to the drive swing plate 4 through the rolling friction of the needle roller bearing 3. The two sets of crankshafts 1 set on the bottom plate 11 of the outer casing and the two sets of drive swing plates 4 are symmetrically arranged on the second arc tooth 601 of the semi-circular arc rack 6 to form a symmetrical driving force, which is used to counteract the eccentric load caused by unilateral force and avoid the swaying of the rack during linear motion. The circumferential oscillation of the drive swing plate 4 is converted into the linear motion of the rack through arc tooth meshing. The arc tooth meshing process is a progressive contact, realizing the linear drive of the linear actuator.

[0055] Working principle: This invention provides a linear actuator and its linear driving method. The invention uses an input motor to drive an input gear, which meshes with a driven gear, causing the driven gear to rotate. The driven gear is fixed and limited by a gear keyway on a crankshaft, thus driving the crankshaft to rotate synchronously. When the crankshaft rotates, an integrally formed eccentric disk on it rotates eccentrically. A needle roller bearing sleeved on the outside of the eccentric disk contacts the inner wall of the swing engagement hole of the drive swing plate. Through the rolling action of the needle roller bearing, the eccentric rotational motion of the eccentric disk is converted into the circumferential oscillation of the drive swing plate. When the drive swing plate oscillates, its first arc tooth meshes with the second arc tooth of a semi-circular arc-shaped rack. Utilizing the arc tooth engagement relationship, the circumferential oscillation of the drive swing plate is converted into the linear movement of the semi-circular arc-shaped rack. The crankshaft is radially limited by an externally sleeved tapered roller bearing, reducing friction during rotation and ensuring the stability of the overall transmission. Simultaneously, a pre-drilled hole on the drive swing plate provides a clearance with the input motor to avoid contact interference during oscillation.

[0056] The needle roller bearing is sleeved on the outside of the eccentric disk. The needle roller bearing supports a number of circumferentially arrayed needle roller columns through a retaining ring frame, and the needle roller columns can roll. The needle roller bearing converts the sliding friction between the outer surface of the eccentric disk and the inner wall of the swinging hole of the drive swing plate into rolling friction, which significantly reduces the friction coefficient, reduces energy loss and component wear. The retaining ring frame ensures that the needle roller columns are evenly distributed around the circumference, so that the radial force of the eccentric disk is evenly transmitted to the swing plate, avoiding local overload and improving transmission smoothness.

[0057] The eccentric disk contacts the inner wall of the swing fitting hole through a needle roller bearing. When rotating eccentrically, the bearing drives the swing plate to swing. The contact area is evenly distributed, which stably converts the circumferential force of the eccentric rotation into the swing torque of the swing plate, ensuring the accuracy and continuity of the swing angle of the swing plate.

[0058] The first arc tooth of the driving swing plate meshes with the second arc tooth of the semi-circular arc rack. When the swing plate swings, it drives the rack to move linearly. Compared with the traditional straight tooth meshing, the arc tooth meshing has a larger contact area and more uniform force distribution, reducing local stress concentration on the tooth surface, reducing tooth surface wear and fracture risk, and improving heavy load bearing capacity. By utilizing the curvature matching relationship of the arc teeth, the circular swing of the swing plate is accurately converted into the linear movement of the rack, realizing efficient conversion of motion mode. Moreover, the meshing process is a progressive contact, reducing impact vibration.

[0059] The input gear meshes with the driven gear. The driven gear is fixed to the end of the crankshaft by the gear keyway. The gear keyway ensures that there is no relative sliding between the driven gear and the crankshaft, realizing rigid power transmission and avoiding power loss or transmission lag. The meshing transmission of the input gear and the driven gear transmits the rotational power of the input motor to the crankshaft according to a fixed transmission ratio, ensuring the stability and controllability of the power input and facilitating the control of the output speed by adjusting the gear parameters.

[0060] At least two sets of tapered roller bearings are fitted around the outside of the crankshaft, and the bearings are supported by the outer ring, inner ring and circumferential array of bearing rollers.

[0061] The above specific embodiments are specific support for the concept proposed in this invention, and should not be used to limit the scope of protection of this invention. Any equivalent changes or modifications made on the basis of this technical solution in accordance with the technical concept proposed in this invention shall still fall within the scope of protection of this invention.

Claims

1. A linear drive, characterized by The utility model relates to a kind of linear driver, including: Half-circular arc rack (6), and slidingly defined on half-circular arc rack (6) drive slide, the drive slide is provided with several layers of drive swing plate (4) engaged with half-circular arc rack (6); The side of the half-circular arc rack (6) is provided with several layers of second arc tooth (601), The side of the drive swing plate (4) is provided with first arc tooth (401) engaged with corresponding second arc tooth (601); The drive slide is rotatably connected with crankshaft (1), and eccentric disc (2) is arranged eccentrically on the crankshaft (1); Drive swing plate (4) is drivingly connected with eccentric disc (2) through needle roller bearing (3), and the crankshaft (1) is drivingly connected with transmission mechanism; The eccentric disc (2) is rotated by transmission mechanism, so as to drive the first arc tooth (401) of the drive swing plate (4) to displace on the tooth surface meshing position of the second arc tooth (601) of half-circular arc rack (6).

2. A linear drive according to claim 1, characterized in that: The transmission mechanism includes input motor (9) arranged on the drive slide, the input motor (9) is drivingly connected with input gear (8), the driven gear (7) connected on the crankshaft (1) is drivingly connected with the input gear (8), the driven gear (7) engaged is rotated by the rotation of the input gear (8), so as to drive the crankshaft (1) to rotate the eccentric disc (2).

3. The linear driver according to claim 2, characterized in that: The drive slide comprises a housing bottom plate (11) and a drive housing (10) arranged oppositely, The upper side or / and the lower side of the half-circular arc rack (6) is provided with a sliding groove, and the housing bottom plate (11) or / and the upper drive housing (10) is provided with a rack limiting clamping edge (12) slidingly defined in the sliding groove.

4. The linear driver according to claim 3, characterized in that: The eccentric disc (2) is eccentrically sleeved on the crankshaft (1), The crankshaft (1) is further provided with a gear key groove (101) engaged with the driven gear (7), And the crankshaft (1) is rotatably connected to the upper drive housing (10) and the housing bottom plate (11) by a tapered roller bearing (102), and the crankshaft (1) is rotated to be limited in the drive slide by the tapered roller bearing (102).

5. A linear drive according to claim 4, characterized in that: The side of the half-circular arc rack (6) is provided with a friction electric patch (13) along the driving displacement track, the annular side of the driven gear (7) is provided with an annular friction patch (16) in contact with the friction electric patch (13), and the housing bottom plate (11) is further provided with a friction mover (1301), the linear displacement of the half-circular arc rack (6) is monitored by the contact between the friction electric patch (13) and the friction mover (1301), for capturing the linear position change of the joint, converting mechanical displacement into electrical signal.

6. A linear drive according to claim 5, characterized in that: Further comprising a friction pad ring (15), the friction pad ring (15) is arranged between the tapered roller bearing (102) and the needle roller bearing (3). And / or, the friction element (1301) comprises several layers of polyimide film, copper electrode, sponge rubber and aluminum alloy substrate stacked together, and the sponge rubber is used to ensure the friction element (1301) and the friction patch (13) to be in full contact. And / or, the side surfaces of the second arc teeth (601) of adjacent layers are symmetrically spliced. And / or, the side surfaces of the first arc teeth (401) of adjacent driving swing plates (4) are symmetrically spliced.

7. A linear drive according to claim 6, characterized in that: An inner surface of the shell bottom plate (11) is fixedly installed with a ring-shaped matching element (1601); the ring-shaped friction patch (16) is used to contact the ring-shaped matching element (1601) to monitor the curve displacement of the crank shaft (1), and when the driven gear (7) rotates, the ring-shaped friction patch (16) can rotate relative to the ring-shaped matching element (1601) to realize detection.

8. A linear drive according to claim 7, characterized in that: The model equation of the first arc tooth (401) is as follows: Reference trochoidal equation: ; Equation of isometric curve: ; Three-dimensional die drawing equation: ; Scaling factor: ; Three-dimensional coordinates: ; wherein t is a parameter variable representing an independent parameter in the equation, and the value range is , wherein n is a positive integer, and t is used to describe the periodic change of the cycloid in the circumferential direction. L is a total length parameter of the cycloid, used for calculating the linear part in the x direction of the reference cycloid equation; n is a period quantity parameter, which determines the total number of periods of the cycloid and is related to the value range of t; R is a base circle radius parameter, which is a core geometric parameter of the cycloid and the rack tooth profile, and affects the curvature of the cycloid and the size of the tooth profile; a coordinate function of the reference cycloid in the x direction for the first arc tooth (401), a coordinate function of the reference cycloid in the y direction for the first arc tooth (401). is the coordinate function of the equidistant curve in the x-direction, is the coordinate function of the equidistant curve in the y-direction; The equation in is the modulus calculation term for the cycloid normal direction, used to normalize the offset and ensure uniformity of the equidistant curve.

9. A linear drive according to claim 8, characterized in that: The model equation of the second arc tooth (601) is as follows: Reference trochoidal equation: ​ A circle is added at the period point t=2kπ: ； ， ； The tooth profile equation after the die is pulled, and the scaling factor is: ; Three-dimensional equation: ； ， ， ； wherein, is a coordinate function of the reference cycloid in the x direction for the second arc tooth (601), is a coordinate function of the reference cycloid in the y direction for the second arc tooth (601). t is a parameter variable representing an independent parameter in the equation, and the value range is where n is a positive integer, and t is used to describe the periodic change of the cycloid in the circumferential direction. L is a total length parameter of the cycloid, used for calculating the linear part in the x direction of the reference cycloid equation; n is a period quantity parameter, which determines the total number of periods of the cycloid and is related to the value range of t; R is a base circle radius parameter, which is a core geometric parameter of the cycloid and the rack tooth profile, and affects the curvature of the cycloid and the size of the tooth profile; is a coordinate function in z-direction for three-dimensional draft, and x-coordinate of the reference trochoid is linearly dependent, with a slope determined by the total height H and the total length L of the trochoid, i.e. ; H is a total height parameter of the three-dimensional structure, used for controlling the height range of the draft stretch; α is a draft angle parameter, which affects the change rate of the scaling factor and determines the inclination degree of the three-dimensional structure in the height direction; is a scaling factor function, which varies with to achieve the draft scaling effect of the three-dimensional structure; , , are the final three-dimensional coordinate functions, representing the coordinates in the x, y, z directions in three-dimensional space, respectively, where and are obtained by multiplying the equidistant curve coordinates by scaling factors, are directly equal to the draw reduction ; k is a period point index parameter, used to identify the position of the added circle in the rack tooth profile; An angle parameter for describing the circumference coordinate of the added circle, which is a circle. Add the function of the x coordinate of the circle at the periodic point by the periodic position 6kπ and the horizontal component of the circle composition; Add the function of the y coordinate of the circle at the periodic point by the constant term 1 and the vertical component of the circle composition; is a scaling factor function for the tooth profile, varying with z, for adjusting the size of the tooth profile in the height direction; , , is the tooth profile final three-dimensional coordinate function, corresponding to the coordinates in x, y, z directions respectively, wherein X and Y are obtained by multiplying the tooth profile base coordinates by the scaling factors , and Z is directly equal to the height parameter z.

10. A linear drive method of a linear drive device, characterized by comprising: The linear driving method comprises the following steps: The transmission mechanism drives the rotation of the crank shaft (1), which drives the eccentric rotation of the eccentric disc (2) to pass through the rolling friction of the needle bearing (3) to the driving swing plate (4), and the two groups of crank shafts (1) and the two groups of driving swing plates (4) arranged on the shell bottom plate (11) are symmetrically arranged on the second arc teeth (601) of the semicircular rack (6) to form a symmetric driving force, which is used to offset the eccentric load generated by single-side stress and avoid the eccentric swing of the rack during linear motion, and the circumferential swing of the driving swing plate (4) is converted into linear motion of the rack through arc tooth engagement, and the arc tooth engagement process is progressive contact, thereby realizing linear driving of the linear driver.

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