Linear actuator with electrostatic protection

Abstract

The utility model 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 sleeved on the outer side of the screw rod and driven by the rotation of the screw rod to do linear telescopic motion, a shell sleeved on 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 provided by the utility model, electrostatic protection is carried out on the first travel switch and the second travel switch, so that the influence of static electricity on the two travel switches and the control unit can be avoided, and the normal use of the linear actuator is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to linear actuator technical field especially linear actuator with electrostatic protection. BACKGROUND

[0002] The linear actuator in prior art includes an actuating unit providing an actuating torque, a screw rod driven to rotate by the actuating torque, an inner tube sleeved on the outer side of the screw rod, and a shell sleeved on the outer side of the inner tube, wherein the outer side of the screw rod is threadedly connected with a transmission nut, the transmission nut is arranged in the inner tube and fixed relative to the inner tube, when the linear actuator works, the actuating unit applies the actuating torque to the screw rod to make the screw rod rotate, the screw rod is screwed back to drive the transmission nut to make linear motion along the screw rod in the axial direction, and then the transmission nut drives the inner tube to make linear extension and contraction motion.

[0003] In order to control the extension and contraction stroke of the inner tube, the first stroke switch and the second stroke switch electrically connected with the control unit are further installed in the shell, the first stroke switch and the second stroke switch are installed on the outer tube and distributed in the radial side of the inner tube along the extension and contraction direction of the inner tube, when the first stroke switch and the second stroke switch are triggered by the transmission nut, signals are transmitted to the control unit, the control unit controls the actuating unit to stop providing the actuating torque according to the signals, and the extension and contraction stroke of the inner tube can be limited.

[0004] The inner tube of the linear actuator in prior art may have static electricity, since the size of the outer tube of the linear actuator in prior art is small, the first stroke switch and the second stroke switch are close to the inner tube, and then the electrical gap between the inner tube and the first stroke switch and the second stroke switch is small, when static electricity is generated, since the static voltage is usually high voltage, the static voltage may break through the gap and be conducted to the stroke switch, in addition, when the transmission nut is a metal part, the static electricity on the inner tube can also be conducted to the stroke switch and the control unit through the transmission nut when the transmission nut triggers the stroke switch, so that the stroke switch is damaged, the performance is reduced, the stroke switch malfunctions, and the electronic elements of the control unit are damaged, thereby affecting the normal use of the linear actuator. UTILITY MODEL CONTENTS

[0005] The utility model wants to solve the technical problem in prior art and provide a linear actuator with electrostatic protection, the first stroke switch and the second stroke switch are protected from static electricity, the influence of static electricity on the two stroke switches and the control unit can be avoided, and the normal use of the linear actuator is ensured.

[0006] To solve the above technical problems, the utility model adopts the following technical scheme:

[0007] The linear actuator with electrostatic protection comprises:

[0008] An actuating unit for providing an actuating torque; and

[0009] A screw rod driven to rotate by the actuating torque; and

[0010] An inner tube sleeved outside the screw rod and driven to linearly extend and retract by the screw rod; and

[0011] A housing sleeved outside the inner tube; and

[0012] A stroke control unit comprising a first stroke switch and a second stroke switch, the first stroke switch and the second stroke switch being distributed along the extending and retracting direction of the inner tube and being distributed at the radial side of the inner tube, so as to limit the extending and retracting stroke of the inner tube.

[0013] The linear actuator further comprises a first insulation member and a second insulation member, the first stroke switch and the inner tube being radially electrically isolated by the first insulation member, and the second stroke switch and the inner tube being radially electrically isolated by the second insulation member.

[0014] In the utility model, the first stroke switch and the inner tube are radially electrically isolated by the first insulation member, and the second stroke switch and the inner tube are radially electrically isolated by the second insulation member, so as to increase the creepage distance between the inner tube and the stroke switch, to realize the electrostatic protection of the first stroke switch and the second stroke switch, and to reduce the influence of static electricity on the two stroke switches and the control unit; in addition, compared with increasing the size of the housing to make the two stroke switches away from the inner tube, to increase the electrical gap between the two stroke switches and the inner tube, the technical scheme of the utility model does not need to expand and reform the existing housing, but only needs to increase the first insulation member and the second insulation member, so as to ensure the compactness of the overall structure of the linear actuator, and to avoid the increase of the housing in the radial dimension, to cause the increase of the manufacturing cost.

[0015] In the linear actuator, the first insulating member is connected to the inner tube near one end of the actuating unit, the second insulating member is supported by the elastic member to be kept in the radial electric isolation position of the second stroke switch, the movement of the first insulating member towards the first stroke switch is used to trigger the first stroke switch, and the movement of the first insulating member towards the second stroke switch can push the second insulating member to trigger the second stroke switch or push the second insulating member away from the radial electric isolation position to trigger the second stroke switch. In this way, the first insulating member can also serve as a trigger for the stroke switch, and no additional trigger component for triggering the first stroke switch or the second stroke switch is needed, 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 towards the second stroke switch, and at this time the inner tube will also move away from the first stroke switch, that is, although the first insulating member moves away from the first stroke switch and loses the protection of the first stroke switch, since the inner tube also moves away from the first stroke switch, the static electricity on the inner tube can also be prevented from being conducted to the first stroke switch, thereby achieving the protection of the first stroke switch. When the first insulating member triggers the first stroke switch, the first insulating member can also serve as the static protection of the first stroke switch. In addition, when the first insulating member does not reach the second stroke switch, the second insulating member is supported by the elastic member to be kept in the radial electric isolation position of the second stroke switch, thereby serving as the static protection of the second stroke switch. When the first insulating member moves towards the second stroke switch, the first insulating member can also push the second insulating member to trigger the second stroke switch or push the second insulating member away from the radial electric isolation position to trigger the second stroke switch, that is, when the second stroke switch is triggered, the static protection of the second stroke switch can also be achieved by the second insulating member or the first insulating member.

[0016] In the linear actuator, the inner tube is connected with a transmission nut made of insulating material, the transmission nut is threadedly connected with the lead screw for transmission, and the first insulating member is connected with the transmission nut or forms a part of the transmission nut. In this way, the overall structure can be made simpler and more compact, and no additional structure is needed to fix the first insulating member.

[0017] In the linear actuator, the first insulating member and the second insulating member are both fixedly arranged relative to the housing, the inner tube is provided with a trigger component made of insulating material, and the trigger component triggers the first stroke switch or the second stroke switch with the linear extension and contraction of the inner tube. In this way, the first insulating member and the second insulating member are convenient to assemble, and the trigger component made of insulating material can also ensure the static protection of the stroke switch when the first stroke switch or the second stroke switch is triggered.

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

[0019] In the linear actuator, the first insulating member is supported by the first elastic member to be kept in a radial electric isolation position relative to the first stroke switch, the second insulating member is supported by the second elastic member to be kept in a radial electric isolation position relative to the second stroke switch, the inner tube is connected with a transmission nut matched with the screw thread of the screw rod, the first insulating member is pushed by the transmission nut to trigger the first stroke switch, and the second insulating member is pushed by the transmission nut to trigger the second stroke switch. In this way, the first stroke switch is triggered by the first insulating member, and the static electricity is prevented by the first insulating member when the first stroke switch is triggered, and the second stroke switch is triggered by the second insulating member, and the static electricity is prevented by the second insulating member when the second stroke switch is triggered, so that the material requirement of the transmission nut is reduced, and the transmission nut can be made of metal to increase the structural strength.

[0020] In the linear actuator, the radial electric isolation of the first insulating member forms a creepage distance of not less than 20 mm between the first stroke switch and the inner tube, and the radial electric isolation of the second insulating member forms a creepage distance of not less than 20 mm between the second stroke switch and the inner tube. Since a creepage distance of 1 mm can block static electricity of 1.5 KV, in order to ensure that the control unit is completely free of static electricity, a creepage distance of not less than 20 mm can block static electricity of 30 KV, so as to meet the protection requirement of static electricity.

[0021] In the 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 way, by setting the electrical gap, the first insulating member and / or the second insulating member can be prevented from being in contact with the inner tube and being damaged by friction, and the difficulty of static electricity conduction to the first insulating member and the second insulating member is blocked by setting the electrical gap, so as to improve the static electricity protection effect.

[0022] In the linear actuator, the first stroke switch is a mechanical micro switch, and a first trigger button is arranged on the side of the first stroke switch facing the inner tube, and the second stroke switch is a mechanical micro switch, and a second trigger button is arranged on the side of the second stroke switch facing the inner tube.

[0023] In the linear actuator, the housing further comprises an outer tube, and the housing further comprises a third insulating member and a fourth insulating member, the outer tube is sleeved on the inner tube, the first stroke switch and the outer tube are radially electrically isolated by the third insulating member, and the second stroke switch and the outer tube are radially electrically isolated by the fourth insulating member. In this way, since the outer tube also has static electricity, the static electricity on the outer tube can be prevented from being conducted to the first stroke switch and the second stroke switch, and the static electricity protection effect of the first stroke switch and the second stroke switch is improved.

[0024] In the linear actuator, the third insulating member and the fourth insulating member are connected into an integrated insulating cover which extends axially along the inner tube and protects the first stroke switch and the second stroke switch. In this way, the number of components of the linear actuator can be reduced.

[0025] In the linear actuator, the insulating cover has a switch strip extending axially along the inner tube, and the first stroke switch and the second stroke switch are mounted on the switch strip, and the wire connected to the first stroke switch and the wire connected to the second stroke switch are routed in the insulating cover. In this way, the wires can be protected by the insulating cover to avoid damage caused by contact and friction with the inner tube or other components.

[0026] In the linear actuator, the first insulating member and the third insulating member form a circumferential closed loop structure surrounding the first stroke switch, and the second insulating member and the fourth insulating member form a circumferential closed loop structure surrounding the second stroke switch. In this way, the first stroke switch and the second stroke switch can be circumferentially insulated to improve the electrostatic protection effect.

[0027] In the 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 packaged in the housing, one end of the inner tube away from the actuating unit is connected with a front pull, and one end of the actuating unit away from the inner tube is connected with a tail pull, and the front pull and the tail pull are both insulating members. In this way, external static electricity is prevented from entering the first stroke switch and the second stroke switch through the front pull and the tail pull through the lead screw, further improving the electrostatic protection effect of the first stroke switch, the second stroke switch and the control unit.

[0028] These features and advantages of the present application will be described in detail in the following specific embodiments, drawings.

DRAWINGS

[0029] The present application will be further described below with reference to the drawings:

[0030] Figure 1 is an exploded schematic view of the linear actuator in the embodiment one of the present application;

[0031] Figure 2 is Figure 1 a partial enlarged schematic view of A in the embodiment one of the present application;

[0032] Figure 3 is a sectional view of the linear actuator in the embodiment one of the present application Figure 1 ;

[0033] Figure 4 is a sectional view of the linear actuator in the embodiment one of the present application Figure 2;

[0034] Figure 5 The schematic view of the creepage distance in the embodiment one of the utility model;

[0035] Figure 6 The structural schematic view of removing the shell, the insulating cover and part of the casing of the linear actuator in the embodiment one of the utility model;

[0036] Figure 7 The front view of Figure 6 ;

[0037] Figure 8 The partial enlarged schematic view of B in Figure 7 ;

[0038] Figure 9 The partial enlarged schematic view of C in Figure 7 ;

[0039] Figure 10 The structural schematic view of the transmission nut in the embodiment two of the utility model.

[0040] Reference signs:

[0041] 100, actuating unit; 110, actuating motor; 120, gear transmission mechanism; 200, screw rod; 210, transmission nut; 211, trigger plate; 300, inner tube; 310, front pull; 400, shell; 410, outer tube; 420, end cover; 430, third insulating piece; 440, fourth insulating piece; 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 strip; 610, positioning groove; 700, first insulating piece; 710, first inclined surface; 800, second insulating piece; 810, protruding block; 811, trigger inclined surface; 820, insertion slot; 900, elastic component; 1000, casing; 1100, tail pull.

DETAILED DESCRIPTION

[0042] The utility model provides linear actuator with static electricity protection, include:

[0043] Provided actuating torque's actuating unit;And,

[0044] Screw rod driven by actuating torque rotation;And,

[0045] Inner tube, the outside of the screw rod is sleeved and is driven by screw rod rotation to make linear telescopic motion;And,

[0046] Shell, the outside of inner tube is sleeved;And,

[0047] The stroke control unit comprises a first stroke switch and a second stroke switch, which are distributed along the inner tube telescopic direction and are distributed on the radial side of the inner tube, thereby limiting the telescopic stroke of the inner tube.

[0048] The linear actuator further comprises a first insulating piece and a second insulating piece, the first stroke switch and the inner tube are radially electrically isolated by the first insulating piece, and the second stroke switch and the inner tube are radially electrically isolated by the second insulating piece.

[0049] In the utility model, the first stroke switch and the inner tube are radially electrically isolated by the first insulating piece, and the second stroke switch and the inner tube are radially electrically isolated by the second insulating piece, so that the creepage distance between the inner tube and the stroke switch can be increased, the electrostatic protection of the first stroke switch and the second stroke switch can be realized, and the influence of static electricity on the two stroke switches and the control unit can be reduced.

[0050] The technical scheme of the utility model does not need to expand and transform the existing shell, but only needs to increase the first insulating piece and the second insulating piece, so that the compactness of the overall structure of the linear actuator is ensured, and the increase of the radial dimension of the shell is avoided, so that the manufacturing cost is increased.

[0051] Embodiment one

[0052] As Figures 1 to 9As shown, the linear actuator with electrostatic protection in the embodiment comprises an actuating unit 100, a lead screw 200, an inner tube 300, a housing 400 and a stroke control unit 500, wherein the actuating unit 100 comprises an actuating motor 110 and a gear transmission mechanism 120, the gear transmission mechanism 120 is in transmission connection with the lead screw 200, so that the actuating torque provided by the actuating unit 100 is applied to the lead screw 200, thereby driving the lead screw 200 to rotate, the inner tube 300 is sleeved on the outer side of the lead screw 200, a transmission nut 210 is threadedly connected to the end of the lead screw 200 close to the actuating unit 100, the transmission nut 210 is fixed in the circumferential direction and the axial direction relative to the inner tube 300, so that when the actuating unit 100 drives the lead screw 200 to rotate, the transmission nut 210 can be driven to linearly displace along the axial direction of the lead screw 200 through the rotation of the lead screw 200, so as to realize the linear extension and contraction of the inner tube 300. In addition, the housing 400 is sleeved on the outer side of the inner tube 300, and the stroke control unit 500 comprises 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, the control unit is electrically connected with the first stroke switch 510 and the second stroke switch 520, and a switch strip 600 extending along the extension and contraction direction of the inner tube 300 is further arranged between the housing 400 and the inner tube 300, the first stroke switch 510 and the second stroke switch 520 are installed on the switch strip 600 and are distributed in the radial side of the inner tube 300 along the extension and contraction direction of the inner tube 300, thereby limiting the extension and contraction stroke of the inner tube 300.

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

[0054] In the embodiment, by making the first stroke switch 510 and the inner tube 300 radially electrically isolated by the first insulating member 700, and making the second stroke switch 520 and the inner tube 300 radially electrically isolated by the second insulating member 800, the creepage distance between the inner tube 300 and the two stroke switches can be increased, so as to realize the electrostatic protection of the first stroke switch 510 and the second stroke switch 520, thereby reducing the influence of static electricity on the two stroke switches and the control unit; in addition, compared with increasing the size of the housing to move the two stroke switches away from the inner tube to increase the electrical gap between the two stroke switches and the inner tube, the technical solution of the embodiment does not need to enlarge and modify the existing housing, 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 of the manufacturing cost caused by the increase of the radial size of the housing.

[0055] Specifically, the first travel switch 510 in the embodiment is a mechanical micro switch, which is provided with a first trigger button 511 on the side facing the inner tube 300 and has a first pin 512 penetrating the switch strip 600 and facing the shell 400; the second travel switch 520 is a mechanical micro switch, which is provided with a second trigger button 521 on the side facing the inner tube 300 and has a second pin 522 penetrating the switch strip 600 and facing the shell 400. Since there is a gap after the shell of the mechanical micro switch is assembled, the first insulating part 700 is arranged in the embodiment to prevent the static electricity of the inner tube 300 from being conducted to the gap between the first trigger button 511 and the first travel switch 510, and the second insulating part 800 is arranged to prevent the static electricity of the inner tube 300 from being conducted to the gap between the second trigger button 521 and the second travel switch 520.

[0056] The first insulating part 700 in the embodiment is connected to the end of the inner tube close to the actuating unit 100. The transmission nut 210 in the 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 part, and the first insulating part 700 constitutes a part of the transmission nut 210. The second insulating part 800 is made of insulating material such as plastic, rubber or wood. The second insulating part 800 is installed on the shell 400 through the elastic part 900 and is kept in the position of radial electrical isolation of the second travel switch 520 under the action of the elastic part 900. That is, the elastic part 900 in the embodiment is an elastic metal sheet. One end of the elastic part 900 is connected to the second insulating part 800, and the other end penetrates the switch strip 600 and is fixedly connected to the end cover 420 of the shell 400 or the outer tube 410 of the shell 400 through a screw. Preferably, the other end of the elastic part 900 is fixedly connected to the end cover 420 of the shell 400. Thus, the elastic part 900 can support the second insulating part 800 to keep it in the position of radial electrical isolation of the second travel switch 520. That is, the second insulating part 800 is located between the second travel switch 520 and the inner tube 300 and keeps the second insulating part 800 from contacting the second trigger button 521.

[0057] As shown in Figure 8 , the second insulating part 800 in the embodiment is provided with a protruding lug 810 facing the second travel switch 520. The projection of the lug 810 is located between the second trigger button 521 and the first travel switch 510. The lug 810 is provided with a trigger inclined surface 811 on the side facing the second trigger button 521. The trigger inclined surface 811 gradually inclines downward in the direction of the first travel switch 510. Figure 9As shown, the first insulation piece 700 is a trigger protrusion protruding on the outer circumferential surface of the transmission nut and extending axially, and the end surface of the trigger protrusion towards the first trigger button 511 is a first inclined surface 710 gradually inclined radially outward towards the other end of the trigger protrusion. In this way, when the first insulation piece 700 moves towards 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 movement of the first insulation piece 700 towards the first travel switch 510 is used to trigger the first travel switch 510. Figure 4 As shown, when the first insulation piece 700 moves towards 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 movement of the first insulation piece 700 towards the first travel switch 510 is used to trigger the first travel switch 510; when the inner tube 300 extends outwards, the first insulation piece 700 is driven by the transmission nut 210 to move towards the second travel switch 520. Since the elastic metal sheet can be deformed, the second insulation piece 800 can be pushed to move rightwards by the first insulation piece 700, so that the trigger inclined surface 811 moves rightwards and triggers the second travel switch 520, that is, the movement of the first insulation piece 700 towards the second travel switch 520 can push the second insulation piece 800 to trigger the second travel switch 520. When the first insulation piece 700 moves away from the second insulation piece 800, the elastic metal sheet drives the second insulation piece 800 to reset to electrostatically protect the second travel switch 520.

[0058] Since the first insulation piece 700 in the embodiment is a part of the transmission nut 210, and the first insulation piece 700 also serves to trigger the travel switch, it is not necessary to additionally provide other trigger components for triggering the first travel switch 510 or the second travel switch 520, that is, the first insulation piece 700 serves two purposes, simplifying the structure; in addition, it should be noted that when the inner tube 300 extends, the first insulation piece 700 moves towards the second travel switch 520, and at this time the inner tube 300 also moves away from the first travel switch 510, that is, although the first insulation piece 700 moves away from the first travel switch 510 and loses the electrostatic protection of the first travel switch 510, since the inner tube 300 also moves away from the first travel switch 510, the static electricity on the inner tube 300 can also be prevented from being conducted to the first travel switch 510, achieving the protection of the first travel switch 510; in addition, when the first insulation piece 700 does not reach the second travel switch 520, the second insulation piece 800 is supported by the elastic component to remain in the radial electrically isolated position of the second travel switch 520, to electrostatically protect the second travel switch 520; when the first insulation piece 700 moves towards the second travel switch 520, the second insulation piece 800 can also be pushed by the first insulation piece 700 to trigger the second travel switch 520, that is, when the second travel switch 520 is triggered, the electrostatic protection of the second travel switch 520 can also be achieved by the second insulation piece 800.

[0059] It is understood that in other embodiments of this utility model, when the transmission nut and the first insulating component are independently processed, the first insulating component can also be fixed to the transmission nut by snap-fit ​​or adhesive. In this case, the transmission nut can be a metal part or a plastic part.

[0060] It is understood that in other embodiments of this utility model, the second insulating member is not provided with a rib. In this case, the end face of the first insulating member facing the second limit switch is a second inclined surface that is radially outward and close to the first inclined surface. When the first insulating member moves toward the second limit switch, the second limit switch can be triggered by pushing the second insulating member away from the radially electrically isolated position and then by the second inclined surface of the first insulating member.

[0061] It is understood that in other embodiments of this utility model, the first insulating member can be set independently of the transmission nut and fixed on the inner tube, that is, the first insulating member and the transmission 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 creates a creepage distance of not less than 20 mm between the first limit switch 510 and the inner tube 300, and the radial electrical isolation of the second insulating member 800 creates a creepage distance of not less than 20 mm between the second limit switch 520 and the inner tube 300. Since a 1 mm creepage distance can block 1.5 kV of electrostatic discharge, to ensure the control unit is completely free of electrostatic discharge, a creepage distance of not less than 20 mm can block 30 kV of electrostatic discharge, thus meeting the electrostatic protection requirements. Figure 5 As shown, when the inner tube 300 is in the retracted state, the creepage distance between the second limit 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 insulator 800, i.e., the path shown by connecting the three arrow lines in the figure; similarly, when the transmission nut 210 is a metal part, and the first insulator 700 is located outside the transmission nut 210, or the first insulator 700 is independently fixed to the inner tube 300, the creepage distance between the first limit switch 510 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 first insulator 700. The shortest path between the trigger buttons 511 is not shown here; however, when the first insulating member 700 is provided on the transmission nut 210 made of insulating material, the creepage distance between the first limit 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 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 20mm is formed between the first limit switch 510 and the inner tube 300. In addition, the creepage path increased by the surface of the transmission nut 210 can also prevent 30KV of static electricity from entering.

[0063] Preferably, there is an electrical gap between the second insulating element 800 and the inner tube 300. This design, by setting an electrical gap, can prevent the second insulating element 800 from contacting the inner tube 300 and being damaged by friction, and can also make it more difficult for static electricity to be conducted to the second insulating element 800, thereby increasing the difficulty of conduction to the second limit switch 520, thus improving the electrostatic protection effect of the second limit switch 520.

[0064] like Figures 1 to 3 As shown, since the first pin 512 of the first limit switch 510 and the second pin 522 of the second limit switch 520 are both positioned facing the outer tube 410 of the housing 400, and since the outer tube 410 may also have static electricity, in order to prevent the static electricity on the outer tube 410 from being conducted to the first limit switch 510 via the first pin 512 and to the second limit switch 520 via the second pin 522, a third insulating member 430 and a fourth insulating member 440 are also provided inside the housing 400 in this embodiment. The outer tube 410 is sleeved outside the inner tube 300. The first limit switch 510 and the outer tube 410 are radially electrically isolated by the third insulating member 430, and the second limit switch 520 and the outer tube 410 are radially electrically isolated by the fourth insulating member 440. The third insulating member 430 and the fourth insulating member 440 are preferably plastic parts.

[0065] Preferably, the third insulating element 430 and the fourth insulating element 440 are connected to form an integral insulating cover, that is, the third insulating element 430 and the fourth insulating element 440 are formed at both ends of the insulating cover. The insulating cover extends axially along the inner tube 300 and houses and protects the first limit switch 510 and the second limit switch 520. This design simplifies the number of components in the linear actuator. Furthermore, the wires connected to the first limit switch 510 and the wires connected to the second limit switch 520 are both routed within the insulating cover. This design protects the wires from contact and friction with the inner tube 300 or other components, preventing damage.

[0066] In this embodiment, the third insulating member 430 has a third opening extending axially. The first insulating member 700 is inserted into the third opening and cooperates with the side walls of the third insulating member 430 located in 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 limit switch 510. The second insulating member 800 has axially extending slots 820 on both sides. The fourth insulating member 440 has a fourth opening extending axially. The side walls of the fourth insulating member 440 located in the fourth opening are inserted into the slots 820, so that the second insulating member 800 and the fourth insulating member 440 form a circumferential closed-loop structure surrounding the second limit switch 520. This design can achieve circumferential insulation isolation between the first limit switch 510 and the second limit switch 520, thereby improving the electrostatic protection effect.

[0067] In addition, the inner wall of the insulating cover is provided with positioning ribs 450, and the switch strip 600 is provided with positioning grooves 610 on both sides, the positioning ribs 450 are inserted into the positioning grooves 610, so that the insulating cover is fixed on the switch strip 600.

[0068] It can be understood that in other embodiments of the utility model, the third insulating part and the fourth insulating part can also be insulating plates.

[0069] It can be understood that in other embodiments of the utility model, the third insulating part and the fourth insulating part are independently arranged.

[0070] Finally, the linear actuator in the embodiment further comprises a shell 1000, the actuating motor 110 and the gear transmission mechanism 120 are encapsulated in the shell 1000, the gear transmission mechanism 120 comprises a worm and gear and / or a planetary gear set, etc., the front pull 310 is connected to one end of the inner tube 300 away from the actuating unit 100, the tail pull 1100 is connected to one end of the actuating unit 100 away from the inner tube 300, and the front pull 310 and the tail pull 1100 are insulating parts, for example, plastic parts. In this way, the external static electricity is prevented from entering the first stroke switch 510 and the second stroke switch 520 through the front pull 310 and the tail pull 1100 through the screw rod 200, and the electrostatic protection effect on the first stroke switch 510, the second stroke switch 520 and the control unit is further improved.

[0071] Embodiment Two

[0072] As shown in Figure 10 Compared with the first embodiment, the difference of the embodiment is that the first insulating part 700 and the second insulating part (not shown in the figure) are fixedly arranged relative to the shell, that is, the first insulating part 700 and the second insulating part are fixedly installed on the switch strip 600, and the inner tube 300 is provided with a trigger part made of insulating material, the trigger part triggers the first stroke switch 510 or the second stroke switch 520 along with the linear expansion and contraction movement of the inner tube 300. In this way, the assembly of the first insulating part 700 and the second insulating part is facilitated, and at the same time, when the first stroke switch 510 or the second stroke switch 520 is triggered, the electrostatic protection on the stroke switch is ensured through the trigger part made of insulating material.

[0073] Specifically, taking the first insulating piece 700 as an example, a first gap is provided between the first insulating piece 700 and the shell of the first travel switch 510, and the outer circumferential side of the transmission nut 210 is provided with a trigger plate 211 extending along the axial direction and beyond the two end faces of the transmission nut 210, both end faces of the trigger plate 211 are inclined, and the two end inclined faces gradually approach radially outward, and the left inclined face can press the first trigger button 511 to trigger the first travel switch 510 by moving the trigger plate 211 to the left to insert into the first gap. Similarly, the mounting mode of the second insulating piece is the same as that of the first insulating piece 700, and the right inclined face of the trigger plate 211 can press the second trigger button to trigger the second travel switch by moving the trigger plate 211 to the right to insert into the gap between the second insulating piece and the shell of the second travel switch 520.

[0074] The first insulating piece 700 and the second insulating piece are both provided with an electrical gap between the inner tube 300. By designing the electrical gap, the first insulating piece 700 and the second insulating piece can be prevented from being in contact with the inner tube 300 and being damaged by friction, and the difficulty of conducting static electricity to the first insulating piece 700 and the second insulating piece 800 can be blocked by the electrical gap, thereby improving the static protection effect.

[0075] Embodiment Three

[0076] Compared with the first embodiment, the difference of the present embodiment is that the mounting mode of the first insulating piece is different, that is, the first insulating piece and the second insulating piece are the same in structure and symmetrically arranged, the first insulating piece is supported by the first elastic component to keep in the radial electrical isolation position of the first travel switch, and the first insulating piece is pushed by the transmission nut to trigger the first travel switch. For details, refer to the structure and elastic mounting mode of the second insulating piece in the first embodiment, and the structure and mounting mode of the second insulating piece are the same as those of the second insulating piece in the first embodiment, and the second insulating piece can also be pushed by the transmission nut to trigger the second travel switch. By this design, the first travel switch can be triggered by the first insulating piece to ensure that the static protection is realized by the first insulating piece when the first travel switch is triggered, and the second travel switch can be triggered by the second insulating piece to ensure that the static protection is realized by the second insulating piece when the second travel switch is triggered, thereby reducing the material requirement of the transmission nut, that is, the transmission nut can be made of metal to increase the structural strength.

[0077] The first insulating piece and the second insulating piece are both provided with an electrical gap between the inner tube. By designing the electrical gap, the first insulating piece and the second insulating piece can be prevented from being in contact with the inner tube and being damaged by friction, and the difficulty of conducting static electricity to the first insulating piece and the second insulating piece can be blocked by the electrical gap, thereby improving the static protection effect.

[0078] The above merely describes a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that the present application includes but is not limited to the contents described in the drawings and the above specific implementation. Any modification not deviating from the function and structural principle of the present application will be included in the scope of the claims.

Claims

1. A linear actuator with electrostatic protection, comprising: an actuating unit for providing an actuating torque; a screw rod driven to rotate by the actuating torque; and an inner tube sleeved on the outer side of the screw rod and driven to linearly extend and retract by the rotation of the screw rod; a housing sleeved on the outer side of the inner tube; and a stroke control unit comprising a first stroke switch and a second stroke switch, which are spaced apart along the extending and retracting direction of the inner tube and are arranged on the radial side of the inner tube, thereby defining the extending and retracting stroke of the inner tube; characterized in that the linear actuator further comprises a first insulating member and a second insulating member, the first stroke switch and the inner tube are radially electrically isolated by the first insulating member, and the second stroke switch and the inner tube are radially electrically isolated by the second insulating member. 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 member to be kept in a position radially electrically isolated from the second stroke switch, the movement of the first insulating member towards the first stroke switch is used to trigger the first stroke switch, and the movement of the first insulating member towards the second stroke switch can push the second insulating member to trigger the second stroke switch or push the second insulating member away from the position radially electrically isolated to trigger the second stroke switch. The inner tube is connected with a transmission nut made of insulating material, the transmission nut is in threaded engagement with the screw rod for transmission, and the first insulating member is connected with the transmission nut or forms a part of the transmission nut. The first insulating member and the second insulating member are both fixedly arranged relative to the housing, and the inner tube is provided with a trigger member made of insulating material, which triggers the first stroke switch or the second stroke switch with the linear extending and retracting movement of the inner tube.

2. The linear actuator with electrostatic protection according to claim 1, wherein, The inner tube is connected with a transmission nut, the transmission nut is in threaded engagement with the screw rod for transmission, and the transmission nut serves as the trigger member.

3. The linear actuator with electrostatic protection of claim 2, wherein, The first insulating member is supported by a first elastic member to be kept in a position radially electrically isolated from the first stroke switch, the second insulating member is supported by a second elastic member to be kept in a position radially electrically isolated from the second stroke switch, the inner tube is connected with a transmission nut in threaded engagement with the screw rod, the first insulating member is pushed by the transmission nut to trigger the first stroke switch, and the second insulating member is pushed by the transmission nut to trigger the second stroke switch.

4. The linear actuator with electrostatic discharge protection of claim 1, wherein, The radial electrical isolation of the first insulating member forms a creepage distance of not less than 20 mm between the first stroke 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 stroke switch and the inner tube.

5. The linear actuator with electrostatic protection of claim 4, wherein, 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.

6. The linear actuator with electrostatic discharge protection of claim 1, wherein, The first stroke switch is a mechanical microswitch, and a first trigger button is arranged on the side of the first stroke switch facing the inner tube, and the second stroke switch is a mechanical microswitch, and a second trigger button is arranged on the side of the second stroke switch facing the inner tube.

7. The linear actuator with electrostatic discharge protection of claim 1, wherein, The housing further comprises an outer tube, the housing is further provided with a third insulating member and a fourth insulating member, the outer tube is sleeved on the outer side of the inner tube, the first stroke switch and the outer tube are radially electrically isolated by the third insulating member, and the second stroke switch and the outer tube are radially electrically isolated by the fourth insulating member.

8. The linear actuator with electrostatic discharge protection of claim 1, wherein, ​ 9. The linear actuator with electrostatic discharge protection of claim 1, wherein, ​ 10. The linear actuator with electrostatic protection according to one of claims 1 to 9, characterized in that ​ 11. The linear actuator with electrostatic protection of claim 10, wherein, The third insulating member and the fourth insulating member are connected into an integrated insulating cover which extends axially along the inner tube and protects the first stroke switch and the second stroke switch.

12. The linear actuator with electrostatic protection of claim 11, wherein, The insulating cover has a switch strip extending axially along the inner tube, and the first stroke switch and the second stroke switch are mounted on the switch strip, and the wire connected with the first stroke switch and the wire connected with the second stroke switch are routed in the insulating cover.

13. The linear actuator with electrostatic discharge protection of claim 10, wherein, The first insulating member and the third insulating member form a circumferential closed loop structure surrounding the first stroke switch, and the second insulating member and the fourth insulating member form a circumferential closed loop structure surrounding the second stroke switch.

14. The linear actuator with electrostatic discharge protection according to one of claims 1 to 9, wherein The actuating unit comprises an actuating motor and a gear transmission mechanism, the linear actuator comprises a casing, the actuating motor and the gear transmission mechanism are packaged in the casing, one end of the inner tube away from the actuating unit is connected with a front pull, and one end of the actuating unit away from the inner tube is connected with a tail pull, and the front pull and the tail pull are both insulating members.

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