An electric cylinder device with high dynamic characteristics and self-locking at extreme positions

Abstract

The present invention relates to the technical field of automobile autonomous braking system, and specifically to an electric cylinder device with high dynamic characteristics and self-locking at extreme positions, comprising a housing, a motor arranged on one side of the housing, a piston slidably arranged in the housing, a transmission mechanism arranged between the piston and the motor in the housing, and an elastic reset member arranged between the piston and the inner wall of the housing in the housing; the transmission mechanism comprises a lead screw pair and a screw pair arranged in the housing, wherein the lead screw pair is a lead screw driven by the motor and a nut matched with the lead screw and can only be arranged in axial translation; the screw pair comprises a screw fixed along the same central axis as the lead screw and a nut matched with the screw and can only be arranged in axial translation; the transmission mechanism has an initial position and a self-locking position, in which the nut is against the piston; in the self-locking position, the nut is separated from the piston, and the nut is against the piston. The electric cylinder device eliminates the need for a manual braking device, has a simple structure, low cost, and is easy to arrange.

Description

Technical Field

[0001] The invention relates to the technical field of automobile autonomous braking systems, in particular to an electric cylinder device with high dynamic characteristics and self-locking at an extreme position. Background Art

[0002] The automobile braking system is closely related to the driving safety of the automobile. The hydraulic braking system of traditional automobiles is achieved by the driver applying braking pressure to the wheel cylinders of each wheel brake by stepping on the brake pedal, thereby braking and slowing down the vehicle. Intelligent automobile systems such as advanced driver assistance systems (ADAS) and automated driving systems (ADS) require that the braking system can brake the vehicle autonomously, that is, brake some or all wheels without stepping on the brake pedal.

[0003] At present, most of the brake systems that can implement autonomous braking use electric power assistance and retain brake control devices such as brake pedals. However, for the development of unmanned logistics delivery vehicles, this method is not applicable because brake control devices are no longer needed. In addition to service brakes, self-driving vehicles such as unmanned logistics delivery vehicles also require parking brakes. Most of the existing motor vehicles are equipped with two systems: service brake system and parking brake system. That is, the existing electric cylinder device can only realize service brakes, but has no parking brake function. To realize the parking function, the vehicle needs to add other parking mechanisms on the basis of the existing brake electric cylinder, which makes its structure and corresponding control more complicated and costly. For service brakes and parking brakes, a certain degree of practical application reliability is also required.

[0004] Therefore, how to design a braking device that has a simple structure, reliable use, low cost and meets both driving and parking braking needs is an urgent problem to be solved in the automatic driving system of motor vehicles. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide an electric cylinder device with a self-locking function and low cost, which can realize parking brake when used in a vehicle braking system.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] An electric cylinder device with high dynamic characteristics and self-locking at an extreme position, comprising a housing, a motor arranged on one side of the housing, and a piston slidably arranged in the housing;

[0008] A transmission mechanism is provided in the housing between the piston and the motor, and an elastic reset member is provided in the housing between the piston and the inner wall of the housing;

[0009] The transmission mechanism comprises a lead screw pair and a screw pair arranged in the housing, wherein the lead screw pair is composed of a lead screw driven by the motor and a screw nut assembly that cooperates with the lead screw and can only be arranged to move in an axial direction;

[0010] The screw pair includes a screw fixed along the same central axis as the lead screw and a nut matched with the screw and capable of only axial translation.

[0011] The lead of the screw is greater than the lead of the lead screw;

[0012] The transmission mechanism has an initial position and a self-locking position. In the initial position, the nut is fitted with the piston; in the self-locking position, the nut is separated from the piston, and the nut is fitted with the piston.

[0013] Furthermore, the transmission mechanism also includes a rotation limiting element, one end of which is fixedly connected to the housing, and the other end of which moves through the nut and the nut in a direction parallel to the same central axis.

[0014] Furthermore, the rotation limiting element is a cylindrical pin, which has a simple structure and low cost.

[0015] Furthermore, the housing includes a transmission housing and a master cylinder housing that are fixedly connected, the motor is arranged on a side of the transmission housing away from the master cylinder housing, and one end of the lead screw is supported on the master cylinder housing through a bearing and connected to the output shaft of the motor.

[0016] Furthermore, the piston is arranged in the master cylinder housing, and a first cavity is formed between one of the end faces of the piston and the inner wall of the master cylinder housing. The outer peripheral surface of the middle part of the piston is recessed inward to form a second cavity between it and the inner wall of the master cylinder housing. The elastic return member is arranged in the first cavity, and the two ends of the elastic return member are respectively abutted against the piston and the inner wall of the master cylinder housing.

[0017] Furthermore, the main cylinder housing is provided with an oil pot, and the main cylinder housing is provided with a liquid supply hole, a compensation hole and a liquid discharge hole, wherein the liquid supply hole connects the second cavity and the oil pot, the compensation hole connects the first cavity and the oil pot, and the liquid discharge hole connects the first cavity, and the piston is provided with a first leather cup, and in the pre-compression state of the elastic reset member, the first leather cup is located between the liquid supply hole and the compensation hole. The movement of the piston drives the movement of the first leather cup, so that the compensation hole C can be opened and closed.

[0018] Furthermore, a second leather cup is provided on the piston, and the second cavity is located between the first leather cup and the second leather cup. The second leather cup is used to prevent the liquid in the second cavity from entering the main cylinder housing, and plays a sealing role.

[0019] Furthermore, a groove for accommodating the screw pair is formed on one side of the nut facing the piston, so that the internal structure of the entire electric cylinder is more compact.

[0020] Furthermore, an I-shaped groove is provided on the end surface of the lead screw away from the motor, and an I-shaped protrusion matching the I-shaped groove is provided on the end surface of the screw connected to the lead screw, and the I-shaped protrusion of the screw is inserted into the I-shaped groove of the lead screw.

[0021] Furthermore, the elastic return element is a return spring.

[0022] The working principle of the present invention when applied to automobile braking is:

[0023] 1. Service brake working condition: The working principle of the present invention in service brake working condition is: the controller receives the brake signal to drive the motor to rotate, which drives the lead screw to rotate, and the screw connected with the lead screw also rotates accordingly. The cylindrical pin limits the rotation of the nut and the nut, so that the nut and the nut can only move horizontally. The nut pushes the piston forward until the first leather cup seals the compensation hole. At this time, the nut continues to push the piston, squeezes the brake fluid in the first cavity to establish high pressure, and outputs the brake pressure from the drain hole to achieve vehicle service braking. Under this working condition, the nut has not yet contacted the piston and has no effect on service braking.

[0024] When the brake needs to be released, the drive motor is powered off, and the nut stops applying axial force to the piston; the piston and the nut return to their initial positions under the action of the reset spring and the hydraulic pressure of the master cylinder; the wheel cylinders of each brake are connected to the first cavity through the brake pipeline and the drain hole, and the first cavity is connected to the oil pot through the compensation hole, so that the brakes of each brake are released after the wheel cylinder pressure is reduced. Under this working condition, the nut's axial movement distance to the left has not exceeded the stroke △x, and it does not contact the right end face of the piston, so it will not apply axial force and has no effect on the brake. When the brake is released, the nut also returns to its initial position under the drive of the screw rod return rotation.

[0025] 2. Parking condition: The same as the braking condition of the vehicle in the same line, the nut converts the rotation of the motor into thrust, pushing the piston to the left. The lead screw and the screw have the same rotation speed, the lead of the screw pair mechanism is larger than that of the screw pair mechanism, and the nut moves faster than the nut. When the pressure generated by the piston reaches the specified value, the nut overcomes the stroke △x and fits the right end face of the piston. At this time, the motor is powered off, and the braking pressure acts on the nut through the piston. Since the screw pair is a single-head screw pair, and the single-head screw pair has a self-locking effect, it will maintain the piston position unchanged, maintain the output pressure of the electric cylinder, and achieve parking.

[0026] The working principle of parking brake release is the same as the working principle of driving brake release.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] The invention discloses an electric cylinder device with high dynamic characteristics and self-locking at the extreme position, which realizes the driving braking condition of the automobile through the screw pair and realizes the parking condition through the cooperation of the screw pair and the screw pair. The electric cylinder device eliminates the need for a human brake device, has a simple structure, low cost and convenient layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the present invention;

[0030] Figure 2 It is a schematic structural diagram of the cylinder body part of the double-chamber electric cylinder in the present invention.

[0031] In the attached figure: 1. motor; 2. first retaining spring; 3. bearing; 4. second retaining spring; 5. cylindrical pin; 6. lead screw; 7. nut; 8. screw; 9. nut; 10. transmission housing; 11. sealing ring; 12. second leather cup; 13. piston; 14. first leather cup; 15. return spring; 16. main cylinder housing; 17. oil pot; A. second cavity; B. liquid supply hole; C. compensation hole; D. first cavity; E. liquid discharge hole.

[0032] 212-first piston; 213-third leather cup; 214-connecting piece; 215-first liquid storage tank; 216-first elastic piece; 217-electric cylinder body; 218-fourth leather cup; 219-second piston; 220-second elastic piece; 221-limiting pin; 222-limiting hole; 214a-cross bar; 214b-partition; A1-third cavity; B1-first liquid supply hole; B2-second liquid supply hole; C1-first compensation hole; C2-second compensation hole; D1-fourth cavity; D2-fifth cavity; E1-first liquid discharge hole; E2-second liquid discharge hole. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0034] Embodiment 1

[0035] like Figure 1 As shown, an electric cylinder device with high dynamic characteristics and self-locking at an extreme position includes a housing and a motor 1 arranged on one side of the housing. In this embodiment, the motor 1 is a servo motor. The housing is composed of a transmission housing 10 and a master cylinder housing 16, and the transmission housing 10 and the master cylinder housing 16 are fastened by fasteners. A sealing ring 11 is also provided between the transmission housing 10 and the master cylinder housing 16 to seal them. In this embodiment, the fastener is a bolt. The motor 1 is arranged on a side of the transmission housing 10 away from the master cylinder housing 16. A plurality of transmission devices are arranged in the transmission housing 10.

[0036] In this embodiment, there is a spiral transmission device inside the transmission housing 10, which mainly includes a screw pair transmission mechanism and a lead screw pair transmission mechanism. The screw pair mechanism in this embodiment is a single-head screw pair mechanism (the self-locking effect of the single-head screw pair is a conventional technical means and will not be described in detail here), including a screw 8 and a nut 9; the lead screw pair transmission mechanism includes a lead screw 6 connected to the motor 1 and a nut 7 that can only move axially.

[0037] In this embodiment, there is a "I"-shaped groove on the left end of the lead screw 6, and a "I"-shaped protrusion on the right end of the screw 8. The "I"-shaped protrusion of the screw 8 is inserted into the "I"-shaped groove of the lead screw 6. The "I"-shaped protrusion and the "I"-shaped groove in this embodiment are interference connected. If other fixed connection methods such as welding, bolt connection, key connection, etc. are used, they should also be within the protection scope of the present invention. The lead screw 6 is supported by a pair of bearings 3, and the lead screw 6 is connected to the output shaft of the motor 1 in an "I" shape. The first retaining spring 2 and the second retaining spring 4 are used for axial positioning of the bearing 3 and limiting the axial movement of the lead screw 6.

[0038] In this embodiment, a rotation limiting element cylindrical pin 5 is provided on the nut 7 and the nut 9, and the axes of the cylindrical pin 5, the lead screw 6, and the screw 8 are all arranged horizontally, and one end of the cylindrical pin 5 is fixedly connected to the hole of the transmission housing 10. In this embodiment, one end of the cylindrical pin 5 is connected to the hole of the transmission housing 10 by interference fit, and other fixed connection methods such as welding, bolt connection, key pin connection, etc. should also be within the protection scope of the present invention. The cylindrical pin 5 can not only limit the rotation of the nut 7 and the nut 9 so that they can only move in translation, but also guide the axial movement of the nut 7 and the nut 9.

[0039] In this embodiment, a piston 13 is slidably arranged in the master cylinder housing 16, and a first cavity D is formed between the left end surface of the piston 13 and the inner wall of the master cylinder housing 16; the outer peripheral surface of the middle part of the piston 13 is recessed inward, and a second cavity A is formed between the recessed surface and the inner wall of the master cylinder housing 16; an elastic return member is also provided between the piston 13 and the inner wall of the master cylinder housing 16, and the elastic return member is a return spring 15.

[0040] In this embodiment, an oil pot 17 is provided on the main cylinder housing 16, and a liquid supply hole B, a compensation hole C and a liquid discharge hole E are provided on the main cylinder housing 16. Among them, the liquid supply hole B connects the second cavity A with the oil pot 17, the compensation hole connects the first cavity D with the oil pot 17, and the liquid discharge hole E connects the first cavity D with the corresponding wheel brake. A first leather cup 14 is provided on the annular step between the first cavity D and the second cavity A on the piston 13. The first leather cup 14 can open and close the compensation hole C as the piston 13 moves. In the initial state, the right end face of the piston 13 contacts the left end face of the nut 7, and the right end face of the nut 7 rests on the limiting boss of the transmission housing. The nut 7 and the return spring 15 work together to make the first leather cup 14 axially located between the compensation hole C and the liquid supply hole B.

[0041] In this embodiment, a second leather cup 12 is provided on the piston 13, and the second cavity A is located between the first leather cup 14 and the second leather cup 12. The second leather cup 12 plays a sealing role to prevent the liquid in the second cavity A from flowing into the transmission housing 10.

[0042] The high dynamic characteristics of the present invention are mainly reflected in that the whole process from the controller receiving the signal to driving the servo motor 1 to rotate (the dynamic response of the servo motor is fast) and driving the piston 13 to move through the transmission mechanism is short, so the vehicle can complete braking in the shortest time.

[0043] The working principle of the present invention in the service braking condition is: the controller receives the braking signal to drive the motor 1 to rotate, driving the screw 6 to rotate, and the screw 8 connected with the screw 6 by interference fit also rotates, and the cylindrical pin 5 limits the rotation of the nut 7 and the nut 9, so that the nut 7 and the nut 9 can only move horizontally, and the nut 7 pushes the piston 13 to move forward until the first leather cup 14 seals the compensation hole C. At this time, the nut 7 continues to push the piston 13, squeezes the brake fluid in the first cavity D to establish high pressure, and outputs the brake pressure from the drain hole E to achieve vehicle service braking. Under this condition, the nut 9 has not yet contacted the piston 13 and has no effect on service braking.

[0044] When the brake needs to be released, the drive motor 1 is powered off, and the nut 7 stops applying axial force to the piston 13; the piston 13 and the nut 7 return to the initial position under the action of the reset spring 15 and the hydraulic pressure of the master cylinder; the wheel cylinders of each brake are connected to the first cavity D through the brake pipeline and the drain hole E, and the first cavity D is connected to the oil pot 17 through the compensation hole C, so that the brakes of each brake are released after the wheel cylinder pressure is reduced. Under this working condition, the axial movement distance of the nut 9 to the left has not exceeded the stroke △x, and there is no contact with the right end face of the piston 13, so no axial force will be applied, and there is no effect on the brake. When the brake is released, the nut 9 also returns to the initial position under the return rotation drive of the screw rod 6.

[0045] The working principle of the present invention in parking condition is: when the braking condition of the vehicle is the same, the nut 7 converts the rotation of the motor 1 into thrust, pushing the piston 13 to move to the left. The lead screw 6 has the same rotation speed as the screw 8, the lead of the screw pair mechanism is larger than that of the screw pair mechanism, the speed of the nut 9 moving is faster than that of the nut 7, and when the pressure generated by the piston 13 reaches the specified value, the nut 9 overcomes the stroke △x and fits the right end face of the piston 13. At this time, the motor is powered off, and the braking pressure acts on the nut 9 through the piston 13. Since the screw pair is a single-head screw pair, and the single-head screw pair has a self-locking effect, it will maintain the position of the piston 13 unchanged, maintain the output pressure of the electric cylinder, and achieve parking.

[0046] The parking brake release works in the same way as the conventional brake release.

[0047] Embodiment 2

[0048] The electric cylinder in the first embodiment can also be configured as a double-chamber electric cylinder in this embodiment; the cylinder body 217 of the double-chamber electric cylinder is as shown in FIG. Figure 2 As shown, other parts are consistent with the first embodiment.

[0049] The piston assembly includes a first piston 212 and a second piston 219 arranged along its sliding direction and a connecting piece 214 for connecting the first piston 212 and the second piston 219. A fourth cavity D1 is formed between the first piston 212, the inner wall of the electric cylinder body 217 and the connecting piece 214, and a fifth cavity D2 is formed between the second piston 219 and the inner wall of the electric cylinder body 217.

[0050] A first elastic member 216 and a second elastic member 220 are disposed in the electric cylinder body 217. The first elastic member 216 is disposed between the connecting member 214 and the first piston 212. The second elastic member 220 is disposed between the electric cylinder body 217 and the second piston 219. The first piston 212 is slidably connected to the connecting member 214.

[0051] A third cavity A1 is formed between the connecting member 214 , the second piston 219 and the inner wall of the electric cylinder body 217 . The connecting member 214 includes a partition 214 b for isolating the fourth cavity D1 from the fifth cavity D2 and a cross bar 214 a extending outward along both sides of the partition 214 b and connected to the first piston 212 and the second piston 219 .

[0052] The specifications of the partition 214b should be compatible with the specifications of the electric cylinder body 217, that is, no oil can pass through. In this embodiment, a leather cup is also added to the partition 214b. The cross bar 214a penetrates the partition 214b and one end thereof is threadedly connected to the second piston 219, and the other end is slidably connected to the first piston 212. The first piston 212 is provided with a third leather cup 213, and the second piston 219 is provided with a fourth leather cup 218.

[0053] The electric cylinder body 217 is provided with: a first compensation hole C1 connecting the first liquid storage tank 215 and the fourth cavity D1, a first liquid supply hole B1 connecting the first liquid storage tank 215, a first liquid discharge hole E1 connecting the fourth cavity D1, a second compensation hole C2 connecting the first liquid storage tank 215 and the fifth cavity D2, a second liquid supply hole B2 connecting the liquid storage tank 215 and the third cavity A1, and a second liquid discharge hole E2 connecting the fifth cavity D2;

[0054] When the first elastic member 216 is in the pre-compression state, the third leather cup 213 is located between the first compensation hole C1 and the first liquid supply hole B1. When the second elastic member 220 is in the pre-compression state, the fourth leather cup 218 is located between the second compensation hole C2 and the second liquid supply hole B2.

[0055] The working principle of the above structure is as follows: under the action of the electric cylinder motor 1, the first piston 212 is subjected to a leftward force, and the pressure of the first elastic member 216 and the second elastic member 220 is always in a balanced state. Under the action of the force of the first elastic member 216 and the second elastic member 220, when the piston assembly moves to the left, the first elastic member 216 will be compressed again, the reaction force will also increase, and the second elastic member 220 will also be compressed.

[0056] In this embodiment, the elastic coefficient of the first elastic member 216 is greater than the elastic coefficient of the second elastic member 220. The elastic coefficient of the first elastic member 216 is greater than the elastic coefficient of the second elastic member 220. In the initial stage, the first piston 212 and the second piston 219 will move to the left together under the action of force to compress the second elastic member 220, and the first elastic member 216 will not be further compressed due to the action of force; during the compression process of the second elastic member 220, its elastic force will gradually increase until it is greater than the force required for the deformation of the first elastic member 216, and the first elastic member 216 will be compressed. The above work continues, and the first elastic member 216 and the second elastic member 220 are always in a balanced state. When the third leather cup 213 and the fourth leather cup 218 block the corresponding compensation holes, high pressure is established in the fourth cavity D1 and the fifth cavity D2, and the oil is discharged through the first drainage hole E1 and the second drainage hole E2 to brake the car.

[0057] In this embodiment, a limit pin 221 is provided on the first piston 212, and a limit hole 222 cooperating with the limit pin 221 is provided on the cross bar 214a. The limit pin 221 and the limit hole 222 are both arranged in the horizontal direction and arranged along the sliding direction of the piston assembly. The first piston 212 is slidably connected to the cross bar 214a through the limit pin 221 and the limit hole 222. When the force compressing the first elastic member 216 is less than the force compressing the second elastic member 220, the limit pin 221 will move to the left along the limit hole 222 driven by the first piston 212, and the second piston 219 will not move; when the force compressing the first elastic member 216 is less than the force compressing the second elastic member 220, the entire piston assembly moves to the left at the same time.

[0058] In this embodiment, the first piston 212 is in abutment with the nut 7 and the nut 9 in the first embodiment, that is, the first piston 212 can move axially under the push of the nut and the nut.

[0059] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An electric cylinder device with high dynamic characteristics and self-locking at an extreme position, comprising a housing, a motor (1) arranged on one side of the housing, and a piston (13) slidably arranged in the housing, characterized in that: A transmission mechanism is provided in the housing between the piston (13) and the motor (1), and an elastic reset member is provided in the housing between the piston (13) and the inner wall of the housing; The transmission mechanism comprises a lead screw pair and a screw pair arranged in a housing, wherein the lead screw pair is composed of a lead screw (6) driven by the motor (1) and a nut (7) matched with the lead screw (6) and arranged to move only in an axial direction; The screw pair comprises a screw (8) fixed along the same central axis as the lead screw (6) and a nut (9) matched with the screw (8) and arranged to move only in an axial direction. The lead of the screw (8) is greater than the lead of the lead screw (6); The transmission mechanism has an initial position and a self-locking position. In the initial position, the nut (7) and the piston (13) are in contact with each other. In the self-locking position, the nut (7) and the piston (13) are separated, and the nut (9) and the piston (13) are in contact with each other. The transmission mechanism further comprises a rotation limiting element, one end of which is fixedly connected to the housing, and the other end of which moves along a direction parallel to the same central axis and passes through the nut (7) and the nut (9); The rotation limiting element is a cylindrical pin (5); The housing comprises a transmission housing (10) and a master cylinder housing (16) which are fixedly connected, the motor (1) is arranged on a side of the transmission housing (10) away from the master cylinder housing (16), and one end of the lead screw (6) is supported on the transmission housing (10) via a bearing (3) and is connected to an output shaft of the motor (1).

2. The electric cylinder device with high dynamic characteristics and self-locking at the extreme position according to claim 1, characterized in that: The piston (13) is arranged in the master cylinder housing (16), and a first cavity (D) is formed between one end surface of the piston (13) and the inner wall of the master cylinder housing (16). The outer peripheral surface of the middle part of the piston (13) is recessed inwards, so that a second cavity (A) is formed between it and the inner wall of the master cylinder housing (16). The elastic return member is arranged in the first cavity (D), and the two ends of the elastic return member are respectively in contact with the piston (13) and the inner wall of the master cylinder housing (16).

3. The electric cylinder device with high dynamic characteristics and self-locking at the extreme position according to claim 2, characterized in that: The master cylinder housing (16) is provided with an oil pot (17), and the master cylinder housing (16) is provided with a liquid supply hole (B), a compensation hole (C) and a liquid discharge hole (E), wherein the liquid supply hole (B) connects the second cavity (A) and the oil pot (17), the compensation hole connects the first cavity (D) and the oil pot (17), and the liquid discharge hole (E) connects the first cavity (D), and the piston (13) is provided with a first leather cup (14), and when the elastic reset member is in a pre-pressed state, the first leather cup (14) is located between the liquid supply hole (B) and the compensation hole (C).

4. The electric cylinder device with high dynamic characteristics and self-locking at the extreme position according to claim 3, characterized in that: The piston (13) is provided with a second leather cup (12), and the second cavity (A) is located between the first leather cup (14) and the second leather cup (12).

5. The electric cylinder device with high dynamic characteristics and self-locking at the extreme position according to claim 1, characterized in that: A groove for accommodating the screw rod pair is formed on a side of the nut (7) facing the piston (13).

6. The electric cylinder device with high dynamic characteristics and self-locking at the extreme position according to claim 1, characterized in that: The end surface of the lead screw (6) away from the motor (1) is provided with an I-shaped groove, and the end surface of the screw rod (8) connected to the lead screw (6) is provided with an I-shaped protrusion matching the I-shaped groove, and the I-shaped protrusion of the screw rod (8) is inserted into the I-shaped groove of the lead screw (6).

7. The electric cylinder device with high dynamic characteristics and self-locking at the extreme position according to claim 1, characterized in that: The elastic return element is a return spring (15).

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