Linear actuator with electrostatic protection

Abstract

The invention discloses a linear actuator with electrostatic protection, which comprises an actuating unit for providing an actuating torque, a screw rod driven by the actuating torque to rotate, an inner pipe which sleeves the outer side of the screw rod and is driven by the rotation of the screw rod to do linear telescopic motion, a shell which sleeves the outer side of the inner pipe, and a stroke control unit, the travel control unit comprises a first travel switch and a second travel switch, and the first travel switch and the second travel switch are distributed on the radial side of the inner pipe at intervals in the telescopic direction of the inner pipe, so that the telescopic travel of the inner pipe is limited; the linear actuator further includes a first insulator and a second insulator, the first travel switch being radially electrically isolated from the inner tube by the first insulator, and the second travel switch being radially electrically isolated from the inner tube by the second insulator. According to the linear actuator, electrostatic protection is carried out on the first travel switch and the second travel switch, the influence of static electricity on the two travel switches and the control unit can be avoided, and normal use of the linear actuator is guaranteed.

Description

[Technical field]

[0001] The invention relates to the technical field of linear actuators, and in particular to a linear actuator with electrostatic protection. [Background technology]

[0002] The linear actuator in the prior art includes an actuating unit that provides an actuating torque, a screw driven to rotate by the actuating torque, an inner tube sleeved on the outside of the screw, and a shell sleeved on the outside of the inner tube, wherein the outer side of the screw is threadedly connected to a transmission nut, the transmission nut is arranged in the inner tube and fixed relative to the inner tube. When the linear actuator is working, the actuating unit applies an actuating torque to the screw to rotate the screw, and the screw is screwed back to drive the transmission nut to perform linear motion along the axial direction of the screw, thereby realizing that the transmission nut drives the inner tube to perform linear telescopic motion.

[0003] In order to control the telescopic stroke of the inner tube, a first stroke switch and a second stroke switch electrically connected to the control unit are also installed in the existing shell. The first stroke switch and the second stroke switch are installed on the outer tube and are distributed at intervals on the radial side of the inner tube along the telescopic direction of the inner tube. When the first stroke switch and the second stroke switch are triggered by the transmission nut, a signal is transmitted to the control unit. The control unit controls the actuating unit to stop providing the actuating torque according to the signal, thereby limiting the telescopic stroke of the inner tube.

[0004] Static electricity may exist in the inner tube of the existing linear actuator. Since the outer tube of the existing linear actuator is small in size, the first travel switch and the second travel switch are close to the inner tube, which leads to a smaller electrical gap between the inner tube and the first travel switch and the second travel switch. When static electricity is generated, since the static electricity voltage is usually high voltage, the static electricity voltage will break through the gap and be transmitted to the travel switch. In addition, when the transmission nut is a metal part, the static electricity on the inner tube can be transmitted to the travel switch and the control unit through the transmission nut when the transmission nut triggers the travel switch, thereby causing damage to the travel switch, performance degradation, malfunction and other problems, as well as damage to the electronic components of the control unit, thereby affecting the normal use of the linear actuator. [Summary of the invention]

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a linear actuator with electrostatic protection. By providing electrostatic protection for the first travel switch and the second travel switch, the influence of static electricity on the two travel switches and the control unit can be avoided, thereby ensuring the normal use of the linear actuator.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] ESD-protected linear actuators, including:

[0008] an actuation unit providing an actuation torque; and,

[0009] a lead screw driven to rotate by an actuating torque; and,

[0010] an inner tube, which is sleeved on the outer side of the screw rod and is driven by the screw rod to perform linear telescopic motion; and,

[0011] a shell, which is sleeved on the outer side of the inner tube; and

[0012] A travel control unit, comprising a first travel switch and a second travel switch, wherein the first travel switch and the second travel switch are spaced apart and distributed on the radial side of the inner tube along the extension direction of the inner tube, thereby limiting the extension travel of the inner tube;

[0013] The linear actuator further comprises a first insulating member and a second insulating member, wherein the first travel switch is radially electrically isolated from the inner tube by the first insulating member, and the second travel switch is radially electrically isolated from the inner tube by the second insulating member.

[0014] In the present invention, the first travel switch and the inner tube are radially electrically isolated by the first insulating member, and the second travel switch and the inner tube are radially electrically isolated by the second insulating member, so that the creepage distance between the inner tube and the travel switch can be increased to achieve electrostatic protection for the first travel switch and the second travel switch, thereby reducing the influence of static electricity on the two travel switches and the control unit; in addition, compared with increasing the size of the shell to keep the two travel switches away from the inner tube to increase the electrical gap between the two travel switches and the inner tube, the technical solution of the present invention does not require the expansion and modification of the existing shell, and only the first insulating member and the second insulating member need to be added, thereby ensuring the compactness of the overall structure of the linear actuator and avoiding the increase in manufacturing costs due to the increase in the radial size of the shell.

[0015] In the above linear actuator, the first insulating member is connected to one end of the inner tube close to the actuating unit, the second insulating member is supported by the elastic member to be maintained in the radial electrical isolation position of the second travel switch, the movement of the first insulating member in the direction of the first travel switch is used to trigger the first travel switch, and the movement in the direction of the second travel switch can push the second insulating member to trigger the second travel switch or push the second insulating member away from the radial electrical isolation position to trigger the second travel switch. With such a design, the first insulating member can also be used to trigger the travel switch, and there is no need to set up other triggering components for triggering the first travel switch or the second travel switch, that is, the first insulating member serves two purposes, simplifying the structure; in addition, when the inner tube is extended, the first insulating member will move in the direction of the second travel switch, and the inner tube will also be away from the first travel switch, that is, although the first insulating member is away from the first travel switch and thus loses the protection of the first travel switch, since the inner tube is also away from the first travel switch, it can also prevent the static electricity on the inner tube from being transmitted to the first travel switch, thereby realizing the protection of the first travel switch, and when the first insulating member is touched When the first travel switch is triggered, the first insulating member can be used to protect the first travel switch from electrostatics; in addition, when the first insulating member has not reached the second travel switch, the second insulating member is supported by the elastic member and maintained in a radial electrical isolation position for the second travel switch to protect the second travel switch from electrostatics; and when the first insulating member moves toward the second travel switch, the second insulating member can be pushed by the first insulating member to trigger the second travel switch, or the second insulating member can be pushed away from the radial electrical isolation position to trigger the second travel switch, that is, when the second travel switch is triggered, the second insulating member or the first insulating member can also be used to protect the second travel switch from electrostatics.

[0016] In the above linear actuator, the inner tube is connected to a transmission nut made of insulating material, the transmission nut and the lead screw thread cooperate for transmission, and the first insulating member is connected to the transmission nut or constitutes a part of the transmission nut. Such a design can make the overall structure simpler and more compact, without the need to set up an additional structure to fix the first insulating member.

[0017] In the above linear actuator, the first insulating member and the second insulating member are both fixedly arranged relative to the housing, and a trigger component made of insulating material is provided on the inner tube, and the trigger component triggers the first travel switch or the second travel switch along with the linear telescopic movement of the inner tube. Such a design facilitates the assembly of the first insulating member and the second insulating member, and also ensures that the travel switch is electrostatically protected by the trigger component made of insulating material when the first travel switch or the second travel switch is triggered.

[0018] In the above linear actuator, the inner tube is connected with a transmission nut, the transmission nut cooperates with the thread of the lead screw for transmission, and the transmission nut serves as the trigger component.

[0019] In the above linear actuator, the first insulating member is supported by the first elastic member to be maintained in a radial electrical isolation position for the first travel switch, the second insulating member is supported by the second elastic member to be maintained in a radial electrical isolation position for the second travel switch, the inner tube is connected to a transmission nut that cooperates with the screw thread, the first insulating member is pushed by the transmission nut to trigger the first travel switch, and the second insulating member is pushed by the transmission nut to trigger the second travel switch. With such a design, the first travel switch is triggered by the first insulating member, which can ensure that electrostatic protection is achieved through the first insulating member when the first travel switch is triggered, and the second travel switch is triggered by the second insulating member, which can ensure that electrostatic protection is achieved through the second insulating member when the second travel switch is triggered, thereby reducing the material requirements for the transmission nut, that is, the transmission nut can be made of metal to increase its structural strength.

[0020] In the above linear actuator, the radial electrical isolation of the first insulating member forms a creepage distance of not less than 20 mm between the first travel switch and the inner tube, and the radial electrical isolation of the second insulating member forms a creepage distance of not less than 20 mm between the second travel switch and the inner tube. Since a creepage distance of 1 mm can block the entry of 1.5 KV static electricity, in order to ensure that the control unit is completely free of static electricity, the creepage distance is not less than 20 mm to block the entry of 30 KV static electricity, thereby meeting the protection requirements for static electricity.

[0021] In the above linear actuator, there is an electrical gap between the first insulating member and the inner tube, and / or there is an electrical gap between the second insulating member and the inner tube. In this design, by setting the electrical gap, it is possible to prevent the first insulating member and / or the second insulating member from contacting the inner tube and being damaged by friction, and by setting the electrical gap, it is possible to block the difficulty of static electricity being transmitted to the first insulating member and the second insulating member, thereby improving the electrostatic protection effect.

[0022] In the above linear actuator, the first travel switch is a mechanical micro switch, and a first trigger button is provided on the side facing the inner tube; the second travel switch is a mechanical micro switch, and a second trigger button is provided on the side facing the inner tube.

[0023] In the above linear actuator, the housing further includes an outer tube, a third insulating member and a fourth insulating member are further provided in the housing, the outer tube is sleeved outside the inner tube, the first travel switch and the outer tube are radially electrically isolated by the third insulating member, and the second travel switch and the outer tube are radially electrically isolated by the fourth insulating member. With such a design, since the outer tube also has static electricity, the static electricity on the outer tube can be prevented from being transmitted to the first travel switch and the second travel switch, thereby improving the static electricity protection effect on the first travel switch and the second travel switch.

[0024] In the above linear actuator, the third insulating member and the fourth insulating member are connected to form an insulating cover of an integral structure, and the insulating cover extends axially along the inner tube and internally houses the first travel switch and the second travel switch for protection. Such a design can simplify the number of parts of the linear actuator.

[0025] In the above linear actuator, the insulating cover has a switch bar extending along the axial direction of the inner tube, the first travel switch and the second travel switch are mounted on the switch bar, and the wires connected to the first travel switch and the wires connected to the second travel switch are both routed in the insulating cover. With such a design, the insulating cover can protect the wires to prevent the wires from contacting or rubbing with the inner tube or other components and being damaged.

[0026] In the above linear actuator, the first insulating member and the third insulating member form a circumferential closed loop structure surrounding the first travel switch, and the second insulating member and the fourth insulating member form a circumferential closed loop structure surrounding the second travel switch. With such a design, circumferential insulation isolation of the first travel switch and the second travel switch can be achieved to improve the electrostatic protection effect.

[0027] In the above linear actuator, the actuating unit includes an actuating motor and a gear transmission mechanism, the linear actuator includes a housing, the actuating motor and the gear transmission mechanism are encapsulated in the housing, the end of the inner tube away from the actuating unit is connected to a front pull, the end of the actuating unit away from the inner tube is connected to a tail pull, and the front pull and the tail pull are both insulating parts. Such a design prevents external static electricity from entering the first travel switch and the second travel switch through the front pull and the tail pull through the lead screw, further improving the electrostatic protection effect of the first travel switch, the second travel switch and the control unit.

[0028] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings.

Brief Description of the Drawings

[0029] The present invention will be further described below in conjunction with the accompanying drawings:

[0030] Figure 1 is an exploded schematic diagram of a linear actuator in Embodiment 1 of the present invention;

[0031] Figure 2 for Figure 1 A is a partial enlarged schematic diagram;

[0032] Figure 3 A cross-sectional view of a linear actuator in Embodiment 1 of the present invention Figure 1 ;

[0033] Figure 4 A cross-sectional view of a linear actuator in Embodiment 1 of the present invention Figure 2 ;

[0034] Figure 5 Schematic diagram of creepage distance in Embodiment 1 of the present invention;

[0035] Figure 6 It is a structural schematic diagram of the linear actuator in Embodiment 1 of the present invention without the shell, the insulating cover and part of the housing;

[0036] Figure 7 for Figure 6 The main view;

[0037] Figure 8 for Figure 7 A partial enlarged schematic diagram of B in the middle;

[0038] Fig. 9 for Figure 7 A partial enlarged schematic diagram of C in the middle;

[0039] Fig.10 It is a schematic diagram of the structure of the transmission nut in the second embodiment of the present invention.

[0040] Reference numerals:

[0041] 100, actuating unit; 110, actuating motor; 120, gear transmission mechanism; 200, lead screw; 210, transmission nut; 211, trigger plate; 300, inner tube; 310, front pull; 400, housing; 410, outer tube; 420, end cover; 430, third insulating member; 440, fourth insulating member; 450, positioning rib; 500, stroke control unit; 510, first stroke switch; 511, first trigger button; 512, first pin; 520, second stroke switch; 521, second trigger button; 522, second pin; 600, switch bar; 610, positioning groove; 700, first insulating member; 710, first inclined plane; 800, second insulating member; 810, bump; 811, trigger inclined plane; 820, slot; 900, elastic member; 1000, housing; 1100, tail pull. [Specific implementation method]

[0042] The present invention provides a linear actuator with electrostatic protection, comprising:

[0043] an actuation unit providing an actuation torque; and,

[0044] a lead screw driven to rotate by an actuating torque; and,

[0045] an inner tube, which is sleeved on the outer side of the screw rod and is driven by the screw rod to perform linear telescopic motion; and,

[0046] a shell, which is sleeved on the outer side of the inner tube; and

[0047] A travel control unit, comprising a first travel switch and a second travel switch, wherein the first travel switch and the second travel switch are spaced apart and distributed on the radial side of the inner tube along the extension direction of the inner tube, thereby limiting the extension travel of the inner tube;

[0048] The linear actuator further comprises a first insulating member and a second insulating member, wherein the first travel switch is radially electrically isolated from the inner tube by the first insulating member, and the second travel switch is radially electrically isolated from the inner tube by the second insulating member.

[0049] In the present invention, the first travel switch and the inner tube are radially electrically isolated by the first insulating member, and the second travel switch and the inner tube are radially electrically isolated by the second insulating member, so that the creepage distance between the inner tube and the travel switch can be increased to achieve electrostatic protection for the first travel switch and the second travel switch, thereby reducing the influence of static electricity on the two travel switches and the control unit; in addition, compared with increasing the size of the shell to keep the two travel switches away from the inner tube to increase the electrical gap between the two travel switches and the inner tube, the technical solution of the present invention does not require the expansion and modification of the existing shell, and only the first insulating member and the second insulating member need to be added, thereby ensuring the compactness of the overall structure of the linear actuator and avoiding the increase in manufacturing costs due to the increase in the radial size of the shell.

[0050] The technical solutions of the embodiments of the present invention are explained and illustrated below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work all belong to the protection scope of the present invention. In addition, it should be understood that the following words indicating orientation or position relationship such as "up", "down", "left", "right", "longitudinal", "lateral", "inside", "outside", "vertical", "horizontal", "top", "bottom", etc. are only based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0051] Embodiment 1

[0052] like Figures 1 to 9As shown, the linear actuator with electrostatic protection in this embodiment includes an actuating unit 100, a screw 200, an inner tube 300, a shell 400 and a stroke control unit 500, wherein the actuating unit 100 includes an actuating motor 110 and a gear transmission mechanism 120, the gear transmission mechanism 120 is transmission-connected to the screw 200 so that the actuating torque provided by the actuating unit 100 is applied to the screw 200, thereby driving the screw 200 to rotate, the inner tube 300 is sleeved on the outside of the screw 200, and a transmission nut 210 is threadedly connected to one end of the outer side of the screw 200 close to the actuating unit 100, and the transmission nut 210 is fixed circumferentially and axially relative to the inner tube 300, so that when the actuating unit 100 drives the screw 200 to rotate, the transmission nut 210 can be driven by the rotation of the screw 200 to perform linear displacement along the axial direction of the screw 200, thereby driving the inner tube 300 to perform linear telescopic movement. In addition, the shell 400 is sleeved on the outside of the inner tube 300, and the stroke control unit 500 includes a first stroke switch 510, a second stroke switch 520 and a control unit (not shown in the figure). The control unit is a control circuit board, and the control unit is electrically connected to the first stroke switch 510 and the second stroke switch 520. A switch bar 600 extending along the telescopic direction of the inner tube 300 is also provided between the shell 400 and the inner tube 300. The first stroke switch 510 and the second stroke switch 520 are installed on the switch bar 600 and are spaced apart on the radial side of the inner tube 300 along the telescopic direction of the inner tube 300, thereby limiting the telescopic stroke of the inner tube 300.

[0053] The linear actuator in this embodiment further includes a first insulating member 700 and a second insulating member 800 . The first travel switch 510 and the inner tube 300 are radially electrically isolated by the first insulating member 700 , and the second travel switch 520 and the inner tube 300 are radially electrically isolated by the second insulating member 800 .

[0054] In this embodiment, the first travel switch 510 is radially electrically isolated from the inner tube 300 by the first insulating member 700, and the second travel switch 520 is radially electrically isolated from the inner tube 300 by the second insulating member 800. This increases the creepage distance between the inner tube 300 and the two travel switches, thereby realizing electrostatic protection for the first travel switch 510 and the second travel switch 520, thereby reducing the influence of static electricity on the two travel switches and the control unit. In addition, compared with increasing the size of the shell to move the two travel switches away from the inner tube to increase the electrical gap between the two travel switches and the inner tube, the technical solution of this embodiment does not require the expansion and modification of the existing shell, and only the first insulating member 700 and the second insulating member 800 need to be added, thereby ensuring the compactness of the overall structure of the linear actuator and avoiding the increase in the radial size of the shell and resulting in an increase in manufacturing costs.

[0055] Specifically, the first travel switch 510 in the present embodiment is a mechanical micro switch, and a first trigger button 511 is provided on the side facing the inner tube 300, and a first pin 512 is provided that penetrates the switch bar 600 and faces the shell 400; the second travel switch 520 is a mechanical micro switch, and a second trigger button 521 is provided on the side facing the inner tube 300, and a second pin 522 is provided that penetrates the switch bar 600 and faces the shell 400. In addition, there is a gap in the shell of the mechanical micro switch after assembly. Therefore, in the present embodiment, the first insulating member 700 is provided to prevent the static electricity of the inner tube 300 from being transmitted to the gap between the first trigger button 511 and the first travel switch 510, and the second insulating member 800 is provided to prevent the static electricity of the inner tube 300 from being transmitted to the gap between the second trigger button 521 and the second travel switch 520.

[0056] The first insulating member 700 in this embodiment is connected to one end of the inner tube close to the actuating unit 100. The transmission nut 210 in this embodiment is made of insulating material. In order to ensure the structural strength of the transmission nut 210, the transmission nut 210 is preferably a plastic member, and the first insulating member 700 constitutes a part of the transmission nut 210; the second insulating member 800 is made of insulating materials such as plastic, rubber or wood. The second insulating member 800 is installed on the shell 400 through an elastic member 900, and the second insulating member 800 is maintained in a radial electrical isolation position for the second travel switch 520 under the action of the elastic member 900, that is, the elastic member 900 in this embodiment is an elastic metal sheet, one end of the elastic member 900 is connected to the second insulating member 800, and the other end passes through the switch bar 600 and is fixedly connected to the end cover 420 of the shell 400 or the outer tube 410 of the shell 400 by screws. Preferably, the other end of the elastic member 900 is fixedly connected to the end cover 420 of the shell 400. In this way, the elastic component 900 can support the second insulating member 800 so that it remains in a radially electrically isolated position with respect to the second travel switch 520, even if the second insulating member 800 is located between the second travel switch 520 and the inner tube 300, and the second insulating member 800 remains in a non-contact state with the second trigger button 521.

[0057] like Figure 8 As shown, in this embodiment, the second insulating member 800 is provided with a protrusion 810 protruding toward the second travel switch 520, and the projection of the protrusion 810 on the second travel switch 520 is located between the second trigger button 521 and the first travel switch 510. The protrusion 810 is provided with a trigger slope 811 on the side facing the second trigger button 521, and the trigger slope 811 gradually slopes downward toward the direction of the first travel switch 510; Fig. 9As shown, the first insulating member 700 is a trigger rib convexly disposed on the outer peripheral surface of the transmission nut and extending along the axial direction thereof, and one end surface of the trigger rib facing the first trigger button 511 is a first inclined surface 710 which is gradually inclined radially outward toward the other end of the trigger rib. Figure 4 As shown, when the first insulating member 700 moves toward the first travel switch 510, the first trigger button 511 can be pressed by the first inclined surface 710 to trigger the first travel switch 510, that is, the first insulating member 700 moves toward the first travel switch 510 to trigger the first travel switch 510; when the inner tube 300 extends outward, the first insulating member 700 moves toward the second travel switch 520 driven by the transmission nut 210. Since the elastic metal sheet can be deformed, the first insulating member 700 can push the second insulating member 800 to move rightward, so that the trigger inclined surface 811 moves rightward and triggers the second travel switch 520, that is, the first insulating member 700 moves toward the second travel switch 520 and can push the second insulating member 800 to trigger the second travel switch 520. When the first insulating member 700 moves away from the second insulating member 800, the elastic metal sheet drives the second insulating member 800 to reset to provide electrostatic protection for the second travel switch 520.

[0058] Since the first insulating member 700 in the present embodiment is a part of the transmission nut 210, and the first insulating member 700 can also serve to trigger the travel switch, there is no need to additionally set up other triggering components for triggering the first travel switch 510 or the second travel switch 520, that is, the first insulating member 700 serves two purposes, thereby simplifying the structure; in addition, it should be noted that when the inner tube 300 is extended, the first insulating member 700 will move toward the second travel switch 520, and at this time the inner tube 300 will also move away from the first travel switch 510, that is, although the first insulating member 700 is away from the first travel switch 510 and thus loses the electrostatic protection for the first travel switch 510, since the inner tube 300 is also away from the first travel switch 510, it can also prevent the static electricity on the inner tube 300 from being transmitted to the second travel switch 520. On a travel switch 510, protection of the first travel switch 510 is realized, and when the first insulating member 700 triggers the first travel switch 510, the first insulating member 700 can be used to protect the first travel switch 510 from electrostatics; in addition, when the first insulating member 700 does not reach the second travel switch 520, the second insulating member 800 is supported by the elastic component and maintained in a radial electrical isolation position for the second travel switch 520 to protect the second travel switch 520 from electrostatics; and when the first insulating member 700 moves toward the second travel switch 520, the second insulating member 800 can also be pushed by the first insulating member 700 to trigger the second travel switch 520, that is, when the second travel switch 520 is triggered, the second insulating member 800 can also be used to achieve electrostatic protection for the second travel switch 520.

[0059] It is understandable that in other embodiments of the present invention, when the drive nut and the first insulating member are independently processed and formed, the first insulating member can also be fixed to the drive nut by snapping or bonding, and the drive nut can be a metal part or a plastic part.

[0060] It can be understood that in other embodiments of the present invention, the second insulating member is not provided with a rib. In this case, the end face of the first insulating member facing the second travel switch is a second inclined surface radially outward and close to the first inclined surface. In this case, when the first insulating member moves toward the second travel switch, the second travel switch can be triggered by pushing the second insulating member away from the radial electrical isolation position and through the second inclined surface of the first insulating member.

[0061] It can be understood that, in other embodiments of the present invention, the first insulating member can be arranged independently of the driving nut and fixed on the inner tube, that is, the first insulating member and the driving nut are distributed along the axial direction of the inner tube.

[0062] In this embodiment, the radial electrical isolation of the first insulating member 700 forms a creepage distance of not less than 20 mm between the first travel switch 510 and the inner tube 300, and the radial electrical isolation of the second insulating member 800 forms a creepage distance of not less than 20 mm between the second travel switch 520 and the inner tube 300. Since a creepage distance of 1 mm can block the entry of 1.5 KV static electricity, in order to ensure that the control unit is completely free of static electricity, the creepage distance is not less than 20 mm to block the entry of 30 KV static electricity, thereby meeting the protection requirements for static electricity. Figure 5 As shown in the figure, when the inner tube 300 is in the retracted state, the creepage distance between the second travel switch 520 and the inner tube 300 refers to the shortest path between the outer side of the inner tube 300 and the second trigger button 521 measured along the surface of the second insulating member 800, that is, the path shown by the three arrow lines connected in the figure; similarly, when the transmission nut 210 is a metal part, the first insulating member 700 is arranged on the outside of the transmission nut 210, or the first insulating member 700 is independently fixed on the inner tube 300, at this time, the creepage distance between the first travel switch 510 and the inner tube 300 refers to the shortest path between the outer side of the inner tube 300 and the first trigger button 521 measured along the surface of the first insulating member 700. The shortest path between the trigger buttons 511 is no longer shown here; and when the first insulating member 700 is arranged on the transmission nut 210 of insulating material, the creepage distance between the first travel switch 510 and the inner tube 300 refers to the shortest path between the outer side surface of the inner tube 300 and the first trigger button 511 measured along the surface of the transmission nut 210 and the first insulating member 700. Due to the radial electrical isolation of the first insulating member 700, a creepage distance of not less than 20 mm is formed between the first travel switch 510 and the inner tube 300. In addition, due to the increased creepage path on the surface of the transmission nut 210, 30KV static electricity can also be blocked from entering.

[0063] Preferably, there is an electrical gap between the second insulating member 800 and the inner tube 300. With such a design, by setting the electrical gap, it is possible to prevent the second insulating member 800 from being damaged by friction due to contact with the inner tube 300, and by setting the electrical gap, it is possible to block the difficulty of static electricity being transmitted to the second insulating member 800, thereby increasing the difficulty of transmitting to the second travel switch 520, thereby improving the static electricity protection effect on the second travel switch 520.

[0064] like Figures 1 to 3 As shown, since the first pin 512 of the first travel switch 510 and the second pin 522 of the second travel switch 520 are both arranged toward the outer tube 410 of the shell 400, and since the outer tube 410 also has static electricity, in order to prevent the static electricity on the outer tube 410 from being transmitted to the first travel switch 510 through the first pin 512, and from being transmitted to the second travel switch 520 through the first pin through the second pin 522, a third insulating member 430 and a fourth insulating member 440 are further provided in the shell 400 in this embodiment, and the outer tube 410 is sleeved outside the inner tube 300, the first travel switch 510 and the outer tube 410 are radially electrically isolated by the third insulating member 430, and the second travel switch 520 and the outer tube 410 are radially electrically isolated by the fourth insulating member 440, and the third insulating member 430 and the fourth insulating member 440 are preferably plastic members.

[0065] Preferably, the third insulating member 430 and the fourth insulating member 440 are connected to form an insulating cover of an integral structure, that is, the third insulating member 430 and the fourth insulating member 440 are formed at both ends of the insulating cover, and the insulating cover extends axially along the inner tube 300 and internally protects the first travel switch 510 and the second travel switch 520. Such a design can simplify the number of parts of the linear actuator. In addition, the wire connected to the first travel switch 510 and the wire connected to the second travel switch 520 are both routed in the insulating cover. With such a design, the wire can be protected by the insulating cover to prevent the wire from contacting and rubbing with the inner tube 300 or other parts and being damaged.

[0066] The third insulating member 430 in this embodiment is provided with a third opening extending in the axial direction, the first insulating member 700 is inserted into the third opening and cooperates with the two side walls of the third insulating member 430 located at the third opening so that the first insulating member 700 and the third insulating member 430 form a circumferential closed loop structure surrounding the first travel switch 510, the two sides of the second insulating member 800 are provided with an axially extending slot 820, the fourth insulating member 440 is provided with a fourth opening extending in the axial direction, and the walls of the fourth insulating member 440 located at both sides of the fourth opening are inserted into the slot 820 so that the second insulating member 800 and the fourth insulating member 440 form a circumferential closed loop structure surrounding the second travel switch 520. With such a design, the circumferential insulation isolation of the first travel switch 510 and the second travel switch 520 can be achieved to improve the electrostatic protection effect.

[0067] In addition, a positioning rib 450 is protruding from the inner wall of the insulating cover, and positioning grooves 610 are provided on both sides of the switch bar 600. The positioning rib 450 is inserted into the positioning groove 610 to fix the insulating cover on the switch bar 600.

[0068] It can be understood that, in other embodiments of the present invention, the third insulating member and the fourth insulating member may also be insulating plates.

[0069] It can be understood that, in other embodiments of the present invention, the third insulating member and the fourth insulating member are independently provided.

[0070] Finally, the linear actuator in this embodiment also includes a housing 1000, an actuating motor 110 and a gear transmission mechanism 120 are encapsulated in the housing 1000, the gear transmission mechanism 120 includes a worm gear and / or a planetary gear set, etc., the end of the inner tube 300 away from the actuating unit 100 is connected to a front pull 310, and the end of the actuating unit 100 away from the inner tube 300 is connected to a tail pull 1100, and the front pull 310 and the tail pull 1100 are both insulating parts, such as plastic parts. Such a design prevents external static electricity from entering the first travel switch 510 and the second travel switch 520 through the front pull 310 and the tail pull 1100 through the lead screw 200, further improving the electrostatic protection effect of the first travel switch 510, the second travel switch 520 and the control unit.

[0071] Embodiment 2

[0072] like Fig.10 As shown, compared with the first embodiment, the difference of this embodiment is that the first insulating member 700 and the second insulating member (not shown in the figure) are both fixedly arranged relative to the housing, that is, the first insulating member 700 and the second insulating member are both fixedly installed on the switch bar 600, and a trigger component made of insulating material is provided on the inner tube 300, and the trigger component triggers the first travel switch 510 or the second travel switch 520 with the linear telescopic movement of the inner tube 300. Such a design facilitates the assembly of the first insulating member 700 and the second insulating member, and also ensures that the travel switch is electrostatically protected by the trigger component made of insulating material when the first travel switch 510 or the second travel switch 520 is triggered.

[0073] Specifically, taking the first insulating member 700 as an example, a first gap is provided between the first insulating member 700 and the housing of the first travel switch 510, and a trigger plate 211 extending along its axial direction and exceeding the two end surfaces of the driving nut 210 is convexly provided on the outer peripheral side of the driving nut 210, and both end surfaces of the trigger plate 211 are inclined surfaces, and the two end inclined surfaces gradually approach radially outward, and the trigger plate 211 is moved to the left and inserted into the first gap, so that the inclined surface on the left side can press the first trigger button 511 to trigger the first travel switch 510. Similarly, the installation method of the second insulating member is the same as that of the first insulating member 700, and the transmission nut 210 drives the trigger plate 211 to move to the right and insert it into the gap between the second insulating member and the housing of the second travel switch 520, so that the inclined surface on the right side of the trigger plate 211 can also press the second trigger button to trigger the second travel switch.

[0074] There is an electrical gap between the first insulating member 700 and the second insulating member and the inner tube 300. In this design, by setting the electrical gap, it is possible to prevent the first insulating member 700 and the second insulating member from being damaged by friction due to contact with the inner tube 300, and the difficulty of static electricity being transmitted to the first insulating member 700 and the second insulating member 800 can be blocked by setting the electrical gap, thereby improving the static electricity protection effect.

[0075] Embodiment 3

[0076] Compared with the first embodiment, the difference of this embodiment is that the installation method of the first insulating member is different, that is, the first insulating member and the second insulating member have the same structure and are symmetrically arranged, the first insulating member is supported by the first elastic member to maintain the radial electrical isolation position of the first travel switch, and the first insulating member is pushed by the transmission nut to trigger the first travel switch. For details, please refer to the structure and elastic installation method of the second insulating member in the first embodiment. The structure and installation method of the second insulating member are the same as the structure and installation method of the second insulating member in the first embodiment. The second insulating member can also be pushed by the transmission nut to trigger the second travel switch. With such a design, the first travel switch is triggered by the first insulating member, which can ensure that the first travel switch is triggered. The electrostatic protection is achieved through the first insulating member, and the second travel switch is triggered by the second insulating member. It can ensure that the electrostatic protection is achieved through the second insulating member when the second travel switch is triggered, thereby reducing the material requirements for the transmission nut, that is, the transmission nut can be made of metal to increase its structural strength.

[0077] There is an electrical gap between the first insulating member and the second insulating member and the inner tube. In this design, by setting the electrical gap, it is possible to prevent the first insulating member and the second insulating member from being damaged by friction due to contact with the inner tube, and by setting the electrical gap, it is possible to block the difficulty of static electricity being transmitted to the first insulating member and the second insulating member, thereby improving the static electricity protection effect.

[0078] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A linear actuator with electrostatic protection, comprising: an actuating unit providing an actuating torque; as well as, A lead screw driven to rotate by an actuating torque; as well as, The inner tube is sleeved on the outer side of the screw rod and is driven by the screw rod to perform linear telescopic motion; as well as, A shell is sleeved on the outer side of the inner tube; and A travel control unit, comprising a first travel switch and a second travel switch, wherein the first travel switch and the second travel switch are spaced apart and distributed on the radial side of the inner tube along the extension direction of the inner tube, thereby limiting the extension travel of the inner tube; It is characterized in that the linear actuator further comprises a first insulating member and a second insulating member, the first travel switch and the inner tube are radially electrically isolated by the first insulating member, and the second travel switch and the inner tube are radially electrically isolated by the second insulating member.

2. The linear actuator with electrostatic protection as claimed in claim 1, characterized in that: The first insulating member is connected to one end of the inner tube close to the actuating unit, and the second insulating member is supported by an elastic component and maintained in a radial electrical isolation position relative to the second travel switch. The movement of the first insulating member in the direction of the first travel switch is used to trigger the first travel switch, and the movement in the direction of the second travel switch can push the second insulating member to trigger the second travel switch or push the second insulating member away from the radial electrical isolation position to trigger the second travel switch.

3. The linear actuator with electrostatic protection as claimed in claim 2, characterized in that: The inner tube is connected to a transmission nut made of insulating material, the transmission nut cooperates with the screw thread for transmission, and the first insulating member is connected to the transmission nut or constitutes a part of the transmission nut.

4. The linear actuator with electrostatic protection as claimed in claim 1, characterized in that: The first insulating member and the second insulating member are both fixedly arranged relative to the shell, and a trigger component made of insulating material is provided on the inner tube. The trigger component triggers the first travel switch or the second travel switch along with the linear telescopic movement of the inner tube.

5. The linear actuator with electrostatic protection as claimed in claim 4, characterized in that: The inner tube is connected with a transmission nut, the transmission nut cooperates with the screw thread for transmission, and the transmission nut serves as the trigger component.

6. The linear actuator with electrostatic protection as claimed in claim 1, characterized in that: The first insulating member is supported by the first elastic member and maintained in a radial electrical isolation position relative to the first travel switch, and the second insulating member is supported by the second elastic member and maintained in a radial electrical isolation position relative to the second travel switch. The inner tube is connected to a transmission nut that cooperates with the screw thread, and the first insulating member is pushed by the transmission nut to trigger the first travel switch, and the second insulating member is pushed by the transmission nut to trigger the second travel switch.

7. The linear actuator with electrostatic protection as claimed in claim 1, characterized in that: The radial electrical isolation of the first insulating member forms a creepage distance of not less than 20 mm between the first travel switch and the inner tube, and the radial electrical isolation of the second insulating member forms a creepage distance of not less than 20 mm between the second travel switch and the inner tube.

8. The linear actuator with electrostatic protection as claimed in claim 1, characterized in that: There is an electrical gap between the first insulating member and the inner tube, and / or there is an electrical gap between the second insulating member and the inner tube.

9. The linear actuator with electrostatic protection as claimed in claim 1, characterized in that: The first travel switch is a mechanical micro switch, and a first trigger button is provided on the side of the first travel switch facing the inner tube. The second travel switch is a mechanical micro switch, and a second trigger button is provided on the side of the second travel switch facing the inner tube.

10. The linear actuator with electrostatic protection according to any one of claims 1 to 9, characterized in that: The shell also includes an outer tube, and a third insulating member and a fourth insulating member are also provided in the shell. The outer tube is sleeved outside the inner tube, and the first travel switch and the outer tube are radially electrically isolated by the third insulating member, and the second travel switch and the outer tube are radially electrically isolated by the fourth insulating member.

11. The linear actuator with electrostatic protection as claimed in claim 10, characterized in that: The third insulating member and the fourth insulating member are connected to form an insulating cover with an integral structure. The insulating cover extends axially along the inner tube and houses the first travel switch and the second travel switch for protection.

12. The linear actuator with electrostatic protection as claimed in claim 11, characterized in that: The insulating cover has a switch bar extending axially along the inner tube, the first travel switch and the second travel switch are mounted on the switch bar, and the wire connected to the first travel switch and the wire connected to the second travel switch are both routed in the insulating cover.

13. The linear actuator with electrostatic protection as claimed in claim 10, characterized in that: The first insulating member and the third insulating member form a circumferential closed loop structure surrounding the first travel switch, and the second insulating member and the fourth insulating member form a circumferential closed loop structure surrounding the second travel switch.

14. The linear actuator with electrostatic protection according to any one of claims 1 to 9, characterized in that: The actuating unit includes an actuating motor and a gear transmission mechanism, the linear actuator includes a housing, the actuating motor and the gear transmission mechanism are encapsulated in the housing, the end of the inner tube away from the actuating unit is connected to a front pull, the end of the actuating unit away from the inner tube is connected to a tail pull, and the front pull and the tail pull are both insulating parts.

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