An electric push rod

Abstract

The present invention discloses an electric push rod, comprising a motor, a transmission gear, a screw and a nut, wherein the transmission gear is fixedly sleeved on the screw, the nut is arranged on the screw, and further comprising a brake assembly and a switch assembly, wherein the self-locking function of the screw is realized by the brake assembly, and the switch assembly comprises a mounting seat, a slider, a rod, a limit block, an elastic member and a travel switch, wherein the slider is mounted on the mounting seat and moves along the length direction of the screw on the mounting seat, the rod and the slider are fixedly connected, and the limit block is movably connected to the rod. The present invention only needs to adjust the position of the limit block on the rod, and does not need to adjust the position of the travel switch, so as to adjust the limit position of the movement of the nut, and there is a sufficient distance between the rod and the screw, and at the same time, the limit block is small in size, and the limit position of the movement of the nut is convenient to adjust, and the self-locking of the screw is realized by the brake assembly, so that the electric push rod will not automatically drop due to the bearing force of the load, thereby improving the operational safety of the electric push rod.

Description

Technical Field

[0001] The invention belongs to the technical field of electric push rods, and in particular relates to an electric push rod. Background Art

[0002] Electric linear actuators, also known as linear actuators, electric cylinders or linear actuators, are electric drive devices that convert the rotational motion of a motor into the reciprocating motion of a push rod. They include linear linear linear actuators, vertical linear actuators and parallel linear actuators. They can be used as actuators in a variety of simple or complex process flows to achieve remote control, centralized control or automatic control.

[0003] The prior art discloses a utility model patent named as an electric push rod (application number: 201620691532.9), which describes the following technical contents in the specific implementation of the specification: a travel bar is provided on the inner wall of the outer tube, the length direction of the travel bar is consistent with the length direction of the outer tube, and the travel bar is evenly provided with jacks. The travel bar is provided with two travel switches for controlling the telescopic travel of the inner tube, and the travel switch is provided with a plug that matches the jack. The motor drives the lead screw to rotate through the worm and the worm gear, and when the lead screw rotates, the transmission nut drives the inner tube to move along the axial direction of the lead screw to realize the telescopic movement of the inner tube relative to the outer tube. The positions of the two travel switches are adjusted according to the travel of the inner tube. When the transmission nut drives the inner tube to move forward until the trigger protrusion on the transmission nut contacts the trigger button on the front travel switch, the motor stops running, and the inner tube moves forward to the limit position. After the motor is started again, the motor reverses and drives the inner tube to move backward. When the trigger protrusion on the transmission nut contacts the trigger button on the rear travel switch, the motor stops running, and the inner tube moves backward to the limit position.

[0004] It can be seen that when the limit position of the inner tube movement needs to be adjusted, the plug of the travel switch needs to be inserted into the jack at different positions of the travel bar. However, the operating space for adjusting the travel switch is limited, and the travel switch has a certain volume, which makes it inconvenient to adjust the limit position of the nut movement. Summary of the invention

[0005] The purpose of the present invention is to provide an electric push rod to address the deficiencies in the prior art. The limit position of the movement of the nut can be adjusted by adjusting the position of the limit block on the rod without adjusting the position of the travel switch. There is a sufficient distance between the rod and the lead screw. At the same time, the limit block is small in size, and the limit position of the movement of the nut is convenient to adjust. The lead screw is self-locking through the brake assembly, so that the electric push rod will not automatically drop due to the bearing force of the load, thereby improving the operational safety of the electric push rod.

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

[0007] An electric push rod comprises a motor, a transmission gear, a lead screw and a nut. The transmission gear is arranged in a gear box, the lead screw is arranged in the gear box through a bearing support, the transmission gear is fixedly sleeved on the lead screw, and the nut is arranged on the lead screw. It is characterized in that it also comprises a brake assembly and a switch assembly. The self-locking function of the lead screw is realized by the brake assembly. The switch assembly comprises a mounting seat, a slider, a rod, a limit block, an elastic member and a travel switch. The mounting seat is limitedly installed in the gear box, the slider is installed on the mounting seat and moves on the mounting seat along the length direction of the lead screw. The rod and the slider are fixedly connected and pass through the nut. The limit block is movably connected to the rod, the elastic member resets the slider, and the travel switch controls the connection motor.

[0008] According to the limit position of the nut on the screw, adjust the position of the limit block on the rod. When the motor drives the screw to rotate, the nut moves along the length of the screw. When the nut touches the limit block and continues to move, the nut moves with the rod, and the rod moves with the slider. The slider touches the contact of the travel switch, so that the circuit connecting the travel switch and the motor is disconnected and the motor stops working. In this way, you only need to adjust the position of the limit block on the rod, without adjusting the position of the travel switch, to adjust the limit position of the nut. There is enough distance between the rod and the screw. At the same time, the limit block is small in size, which is convenient for adjusting the limit position of the nut. By controlling the limit position of the nut, the telescopic distance of the electric push rod is controlled to improve safety.

[0009] Furthermore, the brake assembly includes a brake cup and a brake spring. A positioning sleeve is provided at the end of the transmission gear, and the brake cup is sleeved on the positioning sleeve. The design of the positioning sleeve can enhance the structural strength of the transmission gear itself, while facilitating the sleeve connection between the brake cup and the transmission gear. The positioning sleeve and the transmission gear are an integrally formed structure, which is not only convenient for actual processing and forming, but also can ensure the structural strength and structural firmness of the transmission gear itself. The brake spring sleeve is provided on the outside of the brake cup, and the brake spring and the brake cup are interference fit. One end of the brake spring extends outward to form a positioning part. A positioning groove is provided in the gear box, and the positioning part is limitedly inserted in the positioning groove. The gear box is divided into a two-part shell, and a positioning groove is provided on one side of the shell. The positioning part at the end of the brake spring is located in the positioning groove. After the two shells are installed and closed, the positioning part is limited in the positioning groove. The design is ingenious, and the installation and disassembly are convenient and simple.

[0010] The limit transmission gear is locked together by the brake spring and the brake cup, and the transmission gear is fixedly mounted on the lead screw as a whole, thereby realizing the locking and limiting of the lead screw, so that the electric push rod will not automatically drop due to the bearing force of the load, realizing the self-locking function of the electric push rod, thereby improving the operational safety of the electric push rod, and the design of the brake cup can avoid direct contact between the brake spring and the transmission gear, reduce the wear on the surface of the transmission gear, thereby extending the service life of the transmission gear and saving costs.

[0011] The use of interference-fit brake springs and brake cups can ensure the tightness of the connection between the brake spring and the brake cup, so that the brake spring can achieve different effects according to the rotation direction of the brake cup. When the motor on the electric push rod drives the transmission gear to rotate in the opposite direction of the brake spring, the brake cup and the transmission gear rotate synchronously, that is, the brake cup rotates in the opposite direction of the brake spring. In this state, the brake spring releases the brake cup; when the motor drives the transmission gear to rotate in the same direction of the brake spring, the brake cup and the transmission gear rotate synchronously, that is, the brake cup rotates in the same direction of the brake spring, and the brake spring holds the brake cup to achieve self-locking of the lead screw. By utilizing the reverse force principle of the brake spring, when the lead screw loses its driving force, the bearing capacity of the push rod can be prevented from suddenly dropping due to the load, thereby improving the overall operating safety performance.

[0012] Furthermore, an embedding groove is provided on the outer wall of the positioning sleeve, and an embedding protrusion is provided on the inner wall of the brake cup. The embedding protrusion corresponds to the embedding groove one by one, and the embedding protrusion is embedded and connected in the corresponding embedding groove. The structural design is ingenious and reasonable. Through the snap-fit ​​cooperation between the embedding groove and the embedding protrusion, the precise snap-fitting arrangement between the brake cup and the positioning sleeve is achieved, which is convenient for actual disassembly and assembly, and the embedding protrusion is always embedded in the embedding groove, so that the brake cup and the transmission gear are mutually restrained, so that the brake cup can rotate synchronously with the transmission gear, and a plurality of embedding grooves and embedding protrusions can be provided, thereby forming multiple groups of embedding grooves and embedding protrusions, ensuring the stability and reliability of the snap-fit ​​between the brake cup and the positioning sleeve, improving the stability of the entire braking system, and ensuring the braking effect.

[0013] Furthermore, the transmission gear is a plastic gear, and the brake cup is made of POK, PEEK or POM. The plastic gear is cheap, which reduces costs, and the transmission gear made of plastic is light in weight and can also reduce noise during transmission, thereby improving the user experience of the entire product. The brake cup is made of the above materials, but is not limited to these three materials. Other wear-resistant materials can also be used to ensure the brake cup's own wear resistance and high temperature resistance, making the brake cup not easy to wear and deform, effectively extending the service life of the brake cup and improving the overall braking effect.

[0014] Furthermore, two travel switches are provided, namely, travel switch 1 and travel switch 2, which are distributed along the length direction of the screw rod. At the same time, the rod is provided with two limit blocks, namely, limit block 1 and limit block 2, which are distributed along the length direction of the screw rod, and the nut is provided between limit block 1 and limit block 2.

[0015] When the motor drives the screw to rotate forward, the nut moves toward the direction of limit block 2. When the nut touches limit block 2 and continues to move, the slider touches the contact of travel switch 2, so that the circuit 1 connecting travel switch 2 and the motor is disconnected, and the motor stops driving the screw to rotate forward. At this time, the limit position of the nut's forward movement can be controlled.

[0016] When the motor drives the lead screw to reverse, the elastic member controls the slider to reset, and the nut moves toward the limit block 1. When the nut touches the limit block 1 and continues to move, the slider touches the contact of the travel switch 1, so that the circuit 2 connecting the travel switch 1 and the motor is disconnected, and the motor stops driving the lead screw to reverse. At this time, the nut can be controlled to the limit position of backward movement. In this way, the telescopic distance of the electric push rod can be controlled to improve safety.

[0017] Furthermore, the elastic member adopts a torsion spring, the mounting seat is provided with a connecting column, the torsion spring is inserted into and fixed on the connecting column, the slider is provided with a through hole 1, the torsion spring is provided with a foot, the foot extends into the through hole 1, the slider is provided with a notch, so that the slider forms a convex block, the convex block contacts the contact of the travel switch, the design of the notch can reduce the area of ​​the bottom of the slider, so that the slider is easier to contact the contact of the travel switch, when the convex block contacts the contact of the travel switch, the inner wall of the through hole 1 squeezes the foot to produce deformation, when the slider does not contact the contact of the travel switch, the foot of the torsion spring resets the slider. The design of the connecting column can realize the installation of the torsion spring on the mounting seat, the torsion spring has a simple structure, is easy to install, has sufficient elastic force, and can reset the slider to the initial position.

[0018] Furthermore, the mounting seat is provided with a second through hole, and the slider is provided with a T-shaped positioning block, which passes through the second through hole. The T-shaped positioning block moves in the second through hole along the length direction of the screw rod. The design of the T-shaped positioning block can ensure the stability of the sliding connection between the slider and the mounting seat, and prevent the T-shaped positioning block from falling off the mounting seat. The sliding of the T-shaped block along the second through hole can increase the stability of the movement of the slider.

[0019] Furthermore, the rod is made of stainless steel, the limit block is threadedly connected to the rod, the nut is provided with a connecting portion, the rod passes through the connecting portion, so that the rod and the screw rod maintain a set distance, and the position of the limit block on the rod can be adjusted by twisting the limit block. The connecting portion can realize the installation between the nut and the rod, thereby ensuring the normal movement of the nut and the slider.

[0020] Furthermore, a sleeve is provided on the screw rod, and the sleeve includes an inner tube and an outer tube. The inner tube is sleeved on the outside of the screw rod, and one end of the inner tube is connected to the nut. The outer tube is sleeved on the outside of the inner tube, and one end of the outer tube is connected to the mounting seat. A guide sleeve is provided at the end of the outer tube away from the nut. The inner hole diameter of the guide sleeve matches the outer diameter of the inner tube. The telescopic movement of the inner tube is guided by the guide sleeve, and the rotation of the screw rod is controlled by the motor, so that the nut drives the inner tube to telescope in the outer tube. The guide sleeve plays a guiding role in the telescopic movement of the inner tube, thereby improving the movement accuracy of the push rod.

[0021] Furthermore, a flared opening is provided at the end where the inner tube is connected to the nut, and the flared opening is used to limit the inner tube from falling off. The flared opening design can play a limiting role, limiting the complete separation of the inner tube from the outer tube, thereby improving the overall operational safety.

[0022] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0023] The present invention adjusts the position of the limit block on the rod according to the limit position of the nut on the screw. When the motor drives the screw to rotate, the nut moves on the screw along the length direction of the screw. When the nut touches the limit block and continues to move, the nut moves with the rod, and the rod moves with the slider. The slider touches the contact of the travel switch, so that the circuit connecting the travel switch and the motor is disconnected, and the motor stops working. In this way, only the position of the limit block on the rod needs to be adjusted, and the position of the travel switch does not need to be adjusted, so that the limit position of the nut can be adjusted. There is a sufficient distance between the rod and the screw. At the same time, the size of the limit block is small, and the limit position of the nut is easy to adjust. By controlling the limit position of the nut, the telescopic distance of the electric push rod is controlled to improve safety.

[0024] The structural design of the present invention is ingenious and reasonable, and it is highly practical. The brake spring and the brake cup are used to jointly lock the limit transmission gear, and the transmission gear is fixedly mounted on the lead screw as a whole, thereby realizing the locking and limiting of the lead screw, so that the electric push rod will not automatically drop due to the bearing force of the load, thereby realizing the self-locking function of the electric push rod, thereby improving the operational safety of the electric push rod, and making the operation of the electric push rod more stable and reliable. The design of the brake cup can avoid direct contact between the brake spring and the transmission gear, reduce the wear on the surface of the transmission gear, thereby extending the service life of the transmission gear and saving costs. At the same time, the brake spring and the brake cup can also play a certain buffering role in the telescopic movement of the electric push rod, preventing the electric push rod from suddenly dropping and causing damage or causing danger. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the structure of a switch assembly in Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure in which the rod and the slider are fixedly connected in the first embodiment of the present invention;

[0028] Figure 3 for Figure 2 Right view of;

[0029] Figure 4 Schematic diagram of the structure of the torsion spring in the first embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the mounting base in the first embodiment of the present invention;

[0031] Figure 6 for Figure 1 A schematic diagram of the local enlarged structure at position I in the middle;

[0032] Figure 7 This is a schematic diagram of the structure of the brake assembly in Embodiment 1 of the present invention;

[0033] Figure 8 An exploded view of a brake assembly in Embodiment 1 of the present invention;

[0034] Fig. 9 This is a schematic diagram of the installation structure of the brake assembly in the electric push rod in the first embodiment of the present invention;

[0035] Fig.10 for Fig. 9 A schematic diagram of the local enlarged structure at II in the middle;

[0036] Fig.11 This is a schematic diagram of the structure of the transmission gear in the first embodiment of the present invention;

[0037] Fig.12 This is a schematic diagram of the structure of a brake cup in Embodiment 1 of the present invention;

[0038] Fig.13 This is a schematic diagram of the structure of the brake spring in the first embodiment of the present invention;

[0039] Fig.14 This is a schematic structural diagram of an electric push rod according to an embodiment of the present invention;

[0040] Fig.15 for Fig.14 Schematic diagram of the structure when the middle and outer tubes are removed;

[0041] Fig.16 This is a schematic diagram of the position distribution structure of the expansion opening on the inner tube in the first embodiment of the present invention;

[0042] Fig.17 This is a schematic diagram of the structure of the electric push rod when a low-power motor is used in the first embodiment of the present invention;

[0043] Fig.18 This is a schematic diagram of the structure of an electric push rod according to a second embodiment of the present invention;

[0044] Fig.19 This is a schematic diagram of the installation distribution structure of the switch assembly and the brake assembly in the electric push rod in the second embodiment of the present invention;

[0045] Fig. 20 It is a schematic diagram of the structure of the nut in the second embodiment of the present invention.

[0046] In the figure: 1-motor; 2-screw rod; 3-nut; 4-mounting seat; 5-slider; 6-rod; 7a-limit block one; 7b-limit block two; 8-torsion spring; 9a-travel switch one; 9b-travel switch two; 10-through hole one; 11-slot; 12-bump; 13-positioning block; 14-foot; 15-contact; 16-connecting column; 17-through hole two; 18-connecting part; 19-gear box; 20-bearing; 21-brake cup; 22-brake spring; 23-transmission gear; 24-positioning sleeve; 25-embedded slot; 26-embedded bump; 27-positioning part; 28-positioning slot; 29-sleeve; 30-inner tube; 31-outer tube; 32-guide sleeve; 33-expansion; 34-switch assembly; 35-brake assembly. DETAILED DESCRIPTION

[0047] like Figures 1 to 17 As shown, it is the first embodiment of the present invention, including a motor 1, a transmission gear 23, a screw rod 2 and a nut 3. The transmission gear 23 is arranged in the gear box 19, and the screw rod 2 is supported and arranged in the gear box 19 by a bearing 20. The transmission gear 23 is fixedly sleeved on the screw rod 2, and the nut 3 is arranged on the screw rod 2. It is characterized in that it also includes a brake assembly 35 and a switch assembly 34. The self-locking function of the screw rod 2 is realized by the brake assembly 35. The switch assembly 34 includes a mounting seat 4, a slider 5, a rod 6, a limit block, an elastic member and a travel switch. The mounting seat 4 is limitedly installed in the gear box 19, and the slider 5 is installed on the mounting seat 4 and moves on the mounting seat 4 along the length direction of the screw rod 2. The rod 6 and the slider 5 are fixedly connected and pass through the nut 3. The limit block is movably connected to the rod 6, and the elastic member resets the slider 5. The travel switch controls the connection motor 1.

[0048] According to the limit position of the nut 3 on the screw 2, adjust the position of the limit block on the rod 6. When the motor 1 drives the screw 2 to rotate, the nut 3 moves on the screw 2 along the length direction of the screw 2. When the nut 3 touches the limit block and continues to move, the nut 3 moves with the rod 6, and the rod 6 moves with the slider 5. The slider 5 touches the contact 15 of the travel switch, so that the circuit connecting the travel switch and the motor 1 is disconnected, and the motor 1 stops working. In this way, only the position of the limit block on the rod 6 is adjusted, and there is no need to adjust the position of the travel switch to adjust the limit position of the nut 3. There is a sufficient distance between the rod 6 and the screw 2. At the same time, the size of the limit block is small, and the limit position of the nut 3 is easy to adjust. By controlling the limit position of the nut 3, the telescopic distance of the electric push rod is controlled to improve safety.

[0049] The brake assembly 35 includes a brake cup 21 and a brake spring 22. A positioning sleeve 24 is provided at the end of the transmission gear 23. The brake cup is sleeved on the positioning sleeve 24. The design of the positioning sleeve 24 can enhance the structural strength of the transmission gear 23, and at the same time facilitate the sleeve connection between the brake cup 21 and the transmission gear 23. The positioning sleeve 24 and the transmission gear 23 are an integrally formed structure, which is not only convenient for actual processing and molding, but also can ensure the structural strength and structural firmness of the transmission gear 23. The brake spring 22 is sleeved On the outside of the brake cup 21, the brake spring 22 and the brake cup 21 are interference fit, one end of the brake spring 22 extends outward to form a positioning portion 27, a positioning groove 28 is provided in the gear box 19, and the positioning portion 27 is limitedly inserted in the positioning groove 28. The gear box 19 is divided into two shells, and a positioning groove 28 is provided on one side of the shell. The positioning portion 27 at the end of the brake spring 22 is located in the positioning groove 28. After the two shells are installed and closed, the positioning portion 27 is limited in the positioning groove 28. The design is ingenious, and the installation and disassembly are convenient and simple.

[0050] The brake spring 22 and the brake cup 21 are used to jointly lock the limit transmission gear 23, and the transmission gear 23 is fixedly mounted on the screw rod 2 as a whole, thereby realizing the locking and limiting of the screw rod 2, so that the electric push rod will not automatically drop due to the bearing force of the load, realizing the self-locking function of the electric push rod, thereby improving the operational safety of the electric push rod, and the design of the brake cup 21 can avoid direct contact between the brake spring 22 and the transmission gear 23, reduce the wear on the surface of the transmission gear 23, thereby extending the service life of the transmission gear 23 and saving costs.

[0051] The use of interference fit brake spring 22 and brake cup 21 can ensure the tightness of the socket between the brake spring 22 and the brake cup 21, so that the brake spring 22 can achieve different functions according to the rotation direction of the brake cup 21. When the motor 1 on the electric push rod drives the transmission gear 23 to rotate in the opposite direction of the brake spring 22, the brake cup 21 and the transmission gear 23 rotate synchronously, that is, the brake cup 21 rotates in the opposite direction of the brake spring 22. In this state, the brake spring 22 releases the brake cup 21; when the motor 1 drives the transmission gear 23 to rotate along the rotation direction of the brake spring 22, the brake cup 21 and the transmission gear 23 rotate synchronously, that is, the brake cup 21 rotates along the rotation direction of the brake spring 22, and the brake spring 22 holds the brake cup 21 tightly, thereby realizing the self-locking of the screw rod 2. By utilizing the reverse force principle of the brake spring 22, when the screw rod 2 loses the driving force, the push rod can be prevented from suddenly dropping due to the bearing force of the load, thereby improving the overall operating safety performance.

[0052] An embedding groove 25 is provided on the outer wall of the positioning sleeve 24, and an embedding protrusion 26 is provided on the inner wall of the brake cup 21. The embedding protrusion 26 corresponds to the embedding groove 25 one by one, and the embedding protrusion 26 is embedded and connected in the corresponding embedding groove 25. The structural design is ingenious and reasonable. Through the snap-fit ​​cooperation between the embedding groove 25 and the embedding protrusion 26, the brake cup 21 and the positioning sleeve 24 are accurately snap-fitted, which is convenient for actual disassembly and assembly. The embedding protrusion 26 is always embedded in the embedding groove 25, so that the brake cup 21 and the transmission gear 23 are mutually restrained, so that the brake cup 21 can rotate synchronously with the transmission gear 23. A plurality of embedding grooves 25 and embedding protrusions 26 can be provided, thereby forming multiple groups of embedding grooves 25 and embedding protrusions 26, ensuring the stability and reliability of the snap-fit ​​between the brake cup 21 and the positioning sleeve 24, improving the stability of the entire braking system, and ensuring the braking effect.

[0053] The transmission gear 23 is a plastic gear, and the brake cup 21 is made of POK, PEEK or POM. The plastic gear is cheap, which reduces the cost. The transmission gear 23 made of plastic material is light in weight and can also reduce the noise during the transmission process, thereby improving the user experience of the entire product. The brake cup 21 is made of the above materials, but is not limited to these three materials. Other wear-resistant materials can also be used to ensure the wear resistance and high temperature resistance of the brake cup 21 itself, so that the brake cup 21 is not easy to wear and deform, effectively extending the service life of the brake cup 21 and improving the overall braking effect.

[0054] The present invention sets limit positions for the forward and backward movement of the nut 3: two travel switches are set, namely, travel switch 1 9a and travel switch 2 9b, which are distributed along the length direction of the screw rod 2, and at the same time, the rod 6 is provided with two limit blocks, namely, limit block 1 7a and limit block 2 7b, which are distributed along the length direction of the screw rod 2, and the nut 3 is set between limit block 1 7a and limit block 2 7b. When the motor 1 drives the screw rod 2 to rotate forward, the nut 3 moves in the direction of limit block 2 7b. When the nut 3 touches limit block 2 7b and continues to move, the slider 5 touches the contact 15 of the travel switch 2 9b, so that the circuit connecting the travel switch 2 9b and the motor 1 is disconnected, and the motor 1 stops driving the screw rod 2 to rotate forward. At this time, the limit position of the forward movement of the nut 3 can be controlled. When the motor 1 drives the screw rod 2 to reverse, the elastic member controls the slider 5 to reset, and the nut 3 moves toward the limit block 7a. When the nut 3 touches the limit block 7a and continues to move, the slider 5 presses the contact 15 of the travel switch 9a, so that the circuit 2 connecting the travel switch 9a and the motor 1 is disconnected, and the motor 1 stops driving the screw rod 2 to reverse. At this time, the limit position of the backward movement of the nut 3 can be controlled. In this way, the telescopic distance of the electric push rod can be controlled to improve safety.

[0055] The elastic member is a torsion spring 8, the mounting seat 4 is provided with a connecting column 16, the torsion spring 8 is inserted into and fixed on the connecting column 16, the slider 5 is provided with a through hole 10, the torsion spring 8 is provided with a foot 14, the foot 14 extends into the through hole 10, the slider 5 is provided with a notch 11, so that the slider 5 forms a convex block 12, the convex block 12 contacts the contact 15 of the travel switch, the design of the notch 11 can reduce the area of ​​the bottom of the slider 5, so that the slider 5 is easier to contact the contact 15 of the travel switch, when the convex block 12 contacts the contact 15 of the travel switch, the inner wall of the through hole 10 squeezes the foot 14 to produce deformation, when the slider 5 does not contact the contact 15 of the travel switch, the foot 14 of the torsion spring 8 resets the slider 5. The design of the connecting column 16 can realize the installation of the torsion spring 8 on the mounting seat 4, the torsion spring 8 has a simple structure, is easy to install, has sufficient elastic force, and can reset the slider 5 to the initial position.

[0056] The mounting seat 4 is provided with a second through hole 17, and the slider 5 is provided with a T-shaped positioning block 13. The T-shaped positioning block 13 passes through the second through hole 17. The T-shaped positioning block 13 moves in the second through hole 17 along the length direction of the screw rod 2. The design of the T-shaped positioning block 13 can ensure the stability of the sliding connection between the slider 5 and the mounting seat 4, and prevent the T-shaped positioning block 13 from falling off the mounting seat 4. The T-shaped block slides along the second through hole 17, which can increase the stability of the movement of the slider 5.

[0057] The rod 6 is made of stainless steel, the limit block is threadedly connected to the rod 6, the nut 3 is provided with a connecting portion 18, the rod 6 passes through the connecting portion 18, so that the rod 6 and the screw rod 2 maintain a set distance, and the position of the limit block on the rod 6 can be adjusted by twisting the limit block. The connecting portion 18 can realize the installation between the nut 3 and the rod 6, thereby ensuring the normal movement of the nut 3 and the slider 5.

[0058] The screw rod 2 is provided with a sleeve 29, which includes an inner tube 30 and an outer tube 31. The inner tube 30 is sleeved on the outer side of the screw rod 2, one end of the inner tube 30 is connected to the nut 3, and the outer tube 31 is sleeved on the outer side of the inner tube 30. One end of the outer tube 31 is connected to the mounting seat 4. A guide sleeve 32 is provided at the end of the outer tube 31 away from the nut 3. The inner diameter of the guide sleeve 32 matches the outer diameter of the inner tube 30. The inner tube 30 is guided to move telescopically by the guide sleeve 32. The screw rod 2 is controlled to rotate by the motor 1, so that the nut 3 drives the inner tube 30 to move telescopically in the outer tube 31. The guide sleeve 32 plays a guiding role in the telescopic movement of the inner tube 30, thereby improving the moving accuracy of the push rod. A flare 33 is provided at the end where the inner tube 30 is connected to the nut 3. The flare 33 is used to limit the falling off of the inner tube 30. The design of the flare 33 can play a limiting role, limiting the complete separation of the inner tube 30 from the outer tube 31, thereby improving the overall operation safety.

[0059] like Figure 18-20 As shown, it is a second embodiment of the present invention, including a motor 1, a transmission gear 23, a screw rod 2 and a nut 3. The transmission gear 23 is arranged in a gear box 19, and the screw rod 2 is supported and arranged in the gear box 19 by a bearing 20. The transmission gear 23 is fixedly sleeved on the screw rod 2, and the nut 3 is arranged on the screw rod 2. It is characterized in that it also includes a brake assembly 35 and a switch assembly 34. The self-locking function of the screw rod 2 is realized by the brake assembly 35. The switch assembly 34 includes a mounting seat 4, a slider 5, a rod 6, a limit block, an elastic member and a travel switch. The mounting seat 4 is limitedly installed in the gear box 19, and the slider 5 is installed on the mounting seat 4 and moves on the mounting seat 4 along the length direction of the screw rod 2. The rod 6 and the slider 5 are fixedly connected and pass through the nut 3. The limit block is movably connected to the rod 6, and the elastic member resets the slider 5. The travel switch controls the connection motor 1.

[0060] According to the limit position of the nut 3 on the screw 2, adjust the position of the limit block on the rod 6. When the motor 1 drives the screw 2 to rotate, the nut 3 moves on the screw 2 along the length direction of the screw 2. When the nut 3 touches the limit block and continues to move, the nut 3 moves with the rod 6, and the rod 6 moves with the slider 5. The slider 5 touches the contact 15 of the travel switch, so that the circuit connecting the travel switch and the motor 1 is disconnected, and the motor 1 stops working. In this way, only the position of the limit block on the rod 6 is adjusted, and there is no need to adjust the position of the travel switch to adjust the limit position of the nut 3. There is a sufficient distance between the rod 6 and the screw 2. At the same time, the size of the limit block is small, and the limit position of the nut 3 is easy to adjust. By controlling the limit position of the nut 3, the telescopic distance of the electric push rod is controlled to improve safety.

[0061] The brake assembly 35 includes a brake cup 21 and a brake spring 22. A positioning sleeve 24 is provided at the end of the transmission gear 23. The brake cup is sleeved on the positioning sleeve 24. The design of the positioning sleeve 24 can enhance the structural strength of the transmission gear 23, and at the same time facilitate the sleeve connection between the brake cup 21 and the transmission gear 23. The positioning sleeve 24 and the transmission gear 23 are an integrally formed structure, which is not only convenient for actual processing and molding, but also can ensure the structural strength and structural firmness of the transmission gear 23. The brake spring 22 is sleeved On the outside of the brake cup 21, the brake spring 22 and the brake cup 21 are interference fit, one end of the brake spring 22 extends outward to form a positioning portion 27, a positioning groove 28 is provided in the gear box 19, and the positioning portion 27 is limitedly inserted in the positioning groove 28. The gear box 19 is divided into two shells, and a positioning groove 28 is provided on one side of the shell. The positioning portion 27 at the end of the brake spring 22 is located in the positioning groove 28. After the two shells are installed and closed, the positioning portion 27 is limited in the positioning groove 28. The design is ingenious, and the installation and disassembly are convenient and simple.

[0062] The brake spring 22 and the brake cup 21 are used to jointly lock the limit transmission gear 23, and the transmission gear 23 is fixedly mounted on the screw rod 2 as a whole, thereby realizing the locking and limiting of the screw rod 2, so that the electric push rod will not automatically drop due to the bearing force of the load, realizing the self-locking function of the electric push rod, thereby improving the operational safety of the electric push rod, and the design of the brake cup 21 can avoid direct contact between the brake spring 22 and the transmission gear 23, reduce the wear on the surface of the transmission gear 23, thereby extending the service life of the transmission gear 23 and saving costs.

[0063] The use of interference fit brake spring 22 and brake cup 21 can ensure the tightness of the socket between the brake spring 22 and the brake cup 21, so that the brake spring 22 can achieve different functions according to the rotation direction of the brake cup 21. When the motor 1 on the electric push rod drives the transmission gear 23 to rotate in the opposite direction of the brake spring 22, the brake cup 21 and the transmission gear 23 rotate synchronously, that is, the brake cup 21 rotates in the opposite direction of the brake spring 22. In this state, the brake spring 22 releases the brake cup 21; when the motor 1 drives the transmission gear 23 to rotate along the rotation direction of the brake spring 22, the brake cup 21 and the transmission gear 23 rotate synchronously, that is, the brake cup 21 rotates along the rotation direction of the brake spring 22, and the brake spring 22 holds the brake cup 21 tightly, thereby realizing the self-locking of the screw rod 2. By utilizing the reverse force principle of the brake spring 22, when the screw rod 2 loses the driving force, the push rod can be prevented from suddenly dropping due to the bearing force of the load, thereby improving the overall operating safety performance.

[0064] An embedding groove 25 is provided on the outer wall of the positioning sleeve 24, and an embedding protrusion 26 is provided on the inner wall of the brake cup 21. The embedding protrusion 26 corresponds to the embedding groove 25 one by one, and the embedding protrusion 26 is embedded and connected in the corresponding embedding groove 25. The structural design is ingenious and reasonable. Through the snap-fit ​​cooperation between the embedding groove 25 and the embedding protrusion 26, the brake cup 21 and the positioning sleeve 24 are accurately snap-fitted, which is convenient for actual disassembly and assembly. The embedding protrusion 26 is always embedded in the embedding groove 25, so that the brake cup 21 and the transmission gear 23 are mutually restrained, so that the brake cup 21 can rotate synchronously with the transmission gear 23. A plurality of embedding grooves 25 and embedding protrusions 26 can be provided, thereby forming multiple groups of embedding grooves 25 and embedding protrusions 26, ensuring the stability and reliability of the snap-fit ​​between the brake cup 21 and the positioning sleeve 24, improving the stability of the entire braking system, and ensuring the braking effect.

[0065] The transmission gear 23 is a plastic gear, and the brake cup 21 is made of POK, PEEK or POM. The plastic gear is cheap, which reduces the cost. The transmission gear 23 made of plastic material is light in weight and can also reduce the noise during the transmission process, thereby improving the user experience of the entire product. The brake cup 21 is made of the above materials, but is not limited to these three materials. Other wear-resistant materials can also be used to ensure the wear resistance and high temperature resistance of the brake cup 21 itself, so that the brake cup 21 is not easy to wear and deform, effectively extending the service life of the brake cup 21 and improving the overall braking effect.

[0066] The present invention sets limit positions for the forward and backward movement of the nut 3: two travel switches are set, namely, travel switch 1 9a and travel switch 2 9b, which are distributed along the length direction of the screw rod 2, and at the same time, the rod 6 is provided with two limit blocks, namely, limit block 1 7a and limit block 2 7b, which are distributed along the length direction of the screw rod 2, and the nut 3 is set between limit block 1 7a and limit block 2 7b. When the motor 1 drives the screw rod 2 to rotate forward, the nut 3 moves in the direction of limit block 2 7b. When the nut 3 touches limit block 2 7b and continues to move, the slider 5 touches the contact 15 of the travel switch 2 9b, so that the circuit connecting the travel switch 2 9b and the motor 1 is disconnected, and the motor 1 stops driving the screw rod 2 to rotate forward. At this time, the limit position of the forward movement of the nut 3 can be controlled. When the motor 1 drives the screw rod 2 to reverse, the elastic member controls the slider 5 to reset, and the nut 3 moves toward the limit block 7a. When the nut 3 touches the limit block 7a and continues to move, the slider 5 presses the contact 15 of the travel switch 9a, so that the circuit 2 connecting the travel switch 9a and the motor 1 is disconnected, and the motor 1 stops driving the screw rod 2 to reverse. At this time, the limit position of the backward movement of the nut 3 can be controlled. In this way, the telescopic distance of the electric push rod can be controlled to improve safety.

[0067] The elastic member is a torsion spring 8, the mounting seat 4 is provided with a connecting column 16, the torsion spring 8 is inserted into and fixed on the connecting column 16, the slider 5 is provided with a through hole 10, the torsion spring 8 is provided with a foot 14, the foot 14 extends into the through hole 10, the slider 5 is provided with a notch 11, so that the slider 5 forms a convex block 12, the convex block 12 contacts the contact 15 of the travel switch, the design of the notch 11 can reduce the area of ​​the bottom of the slider 5, so that the slider 5 is easier to contact the contact 15 of the travel switch, when the convex block 12 contacts the contact 15 of the travel switch, the inner wall of the through hole 10 squeezes the foot 14 to produce deformation, when the slider 5 does not contact the contact 15 of the travel switch, the foot 14 of the torsion spring 8 resets the slider 5. The design of the connecting column 16 can realize the installation of the torsion spring 8 on the mounting seat 4, the torsion spring 8 has a simple structure, is easy to install, has sufficient elastic force, and can reset the slider 5 to the initial position.

[0068] The mounting seat 4 is provided with a second through hole 17, and the slider 5 is provided with a T-shaped positioning block 13. The T-shaped positioning block 13 passes through the second through hole 17. The T-shaped positioning block 13 moves in the second through hole 17 along the length direction of the screw rod 2. The design of the T-shaped positioning block 13 can ensure the stability of the sliding connection between the slider 5 and the mounting seat 4, and prevent the T-shaped positioning block 13 from falling off the mounting seat 4. The T-shaped block slides along the second through hole 17, which can increase the stability of the movement of the slider 5.

[0069] The rod 6 is made of stainless steel, the limit block is threadedly connected to the rod 6, the nut 3 is provided with a connecting portion 18, the rod 6 passes through the connecting portion 18, so that the rod 6 and the screw rod 2 maintain a set distance, and the position of the limit block on the rod 6 can be adjusted by twisting the limit block. The connecting portion 18 can realize the installation between the nut 3 and the rod 6, thereby ensuring the normal movement of the nut 3 and the slider 5.

[0070] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. An electric linear actuator, comprising: Motor; A transmission gear, wherein the transmission gear is arranged in a gear box; A screw rod, the screw rod is arranged in the gear box through a bearing support, and the transmission gear is fixedly sleeved on the screw rod; A nut, the nut being arranged on the screw rod; It is characterized by further comprising: A brake assembly, through which the self-locking function of the screw rod is realized; A switch assembly, the switch assembly comprising a mounting seat, a slider, a rod, a limit block, an elastic member and a travel switch, the mounting seat is limitedly mounted in the gear box, the slider is mounted on the mounting seat and moves along the length direction of the lead screw on the mounting seat, the rod and the slider are fixedly connected and pass through the nut, the limit block is movably connected to the rod, the elastic member resets the slider, and the travel switch controls the connection with the motor; When the motor drives the screw rod to rotate, the nut moves on the screw rod along the length direction of the screw rod. When the nut touches the limit block and continues to move, the nut moves with the rod, and the rod moves with the slider. The slider presses the contact of the travel switch, so that the circuit connecting the travel switch and the motor is disconnected, and the motor stops working. The elastic member is a torsion spring, the mounting seat is provided with a connecting column, the torsion spring is inserted into and fixed on the connecting column, the slider is provided with a through hole 1, the torsion spring is provided with a foot, the foot extends into the through hole 1, the slider is provided with a notch, so that the slider forms a convex block, the convex block contacts the contact of the travel switch, and when the convex block contacts the contact of the travel switch, the inner wall of the through hole 1 squeezes the foot to cause deformation; The mounting seat is provided with a second through hole, the slider is provided with a T-shaped positioning block, the T-shaped positioning block passes through the second through hole, and the T-shaped positioning block moves in the second through hole along the length direction of the screw rod; The rod is made of a stainless steel rod, the limit block is threadedly connected to the rod, the nut is provided with a connecting portion, and the rod passes through the connecting portion, so that the rod and the screw rod maintain a set distance.

2. The electric push rod according to claim 1, characterized in that: The brake assembly includes a brake cup and a brake spring. A positioning sleeve is provided at the end of the transmission gear. The brake cup is sleeved on the positioning sleeve. The brake spring is sleeved on the outside of the brake cup, and the brake spring and the brake cup are interference fit. One end of the brake spring extends outward to form a positioning portion. A positioning groove is provided in the gear box, and the positioning portion is limitedly inserted in the positioning groove.

3. The electric push rod according to claim 2, characterized in that: An embedding groove is arranged on the outer side wall of the positioning sleeve, and an embedding protrusion is arranged on the inner side wall of the brake cup. The embedding protrusion corresponds to the embedding groove one by one, and the embedding protrusion is embedded and connected in the corresponding embedding groove.

4. The electric push rod according to claim 2, characterized in that: The transmission gear is a plastic gear, and the brake cup is made of POK, PEEK or POM.

5. The electric push rod according to claim 1, characterized in that: Two travel switches are provided, namely, travel switch 1 and travel switch 2, and the travel switch 1 and the travel switch 2 are distributed along the length direction of the screw rod. At the same time, the rod member is provided with two limit blocks, namely, limit block 1 and limit block 2, and the limit block 1 and the limit block 2 are distributed along the length direction of the screw rod. The nut is provided between the limit block 1 and the limit block 2; when the motor drives the screw rod to rotate forward, the nut moves in the direction of the limit block 2, when the nut touches the limit block 2 and continues to move, the slider touches the contact of the travel switch 2, so that the circuit 1 connecting the travel switch 2 and the motor is disconnected, and the motor stops driving the screw rod to rotate forward; when the motor drives the screw rod to reverse, the elastic member controls the slider to reset, and the nut moves in the direction of the limit block 1, when the nut touches the limit block 1 and continues to move, the slider touches the contact of the travel switch 1, so that the circuit 2 connecting the travel switch 1 and the motor is disconnected, and the motor stops driving the screw rod to reverse.

6. The electric linear actuator according to claim 1, characterized in that: The screw rod is provided with a sleeve, and the sleeve includes an inner tube and an outer tube. The inner tube is sleeved on the outer side of the screw rod, and one end of the inner tube is connected to the nut. The outer tube is sleeved on the outer side of the inner tube, and one end of the outer tube is connected to the mounting seat. A guide sleeve is provided at the end of the outer tube away from the nut, and the inner hole diameter of the guide sleeve matches the outer diameter of the inner tube. The telescopic movement of the inner tube is guided by the guide sleeve.

7. The electric push rod according to claim 6, characterized in that: A flared opening is provided at the end of the inner tube connected to the nut, and the flared opening is used to limit the inner tube from falling off.

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