An electric strut for a car tailgate

Abstract

The invention relates to an electric support rod for a car tailgate, wherein a screw is arranged in a guide tube, a telescopic tube is slidably fitted in the guide tube, one end of the telescopic tube is threadably fitted with the screw through a nut, the other end of the telescopic tube is connected to a second hinge seat, the screw is supported in a motor protection sleeve through a bearing, one end of the bearing is axially positioned by a limiting boss arranged on the screw, and the other end is axially limited by a friction ring fixedly connected to the screw, a clamping mechanism for preventing the telescopic tube from retracting is arranged in the motor protection sleeve, the clamping mechanism comprises two bearings arranged opposite to each other and a force storage spring applying pressure to the bearings, inferior arc grooves are arranged at the opposite ends of the two bearings, the inferior arc grooves of the two bearings correspond to the outer circle of the friction ring, the radius of the inferior arc grooves is the same as the radius of the friction ring, spring mounting holes are arranged at opposite ends of the two bearings, one end of the force storage spring is located in the spring mounting hole, and the other end abuts against the motor protection sleeve, and the inferior arc grooves of the two bearings form a friction fit with the boss on the screw under the action of the force storage spring.

Description

Technical Field

[0001] The present invention relates to the field of automotive tailgate struts, and particularly to an electric strut for an automotive tailgate. Background Art

[0002] With the development of automotive electronics and intelligence, it greatly facilitates people's usage requirements, and the automotive electric tailgate system emerges as the times require. When the user electrically opens the tailgate through switches such as the car key button, the driver's seat switch, and the tailgate external switch, the user can set the opening angle of the tailgate according to their own usage habits to meet the needs of loading goods. In this way, it is necessary to set a hovering angle within the designed angle range according to the user's habits to control the opening state of the tailgate.

[0003] The automotive electric tailgate system mainly consists of an ECU, an electric strut, and an electric suction lock. When the user hopes to open the tailgate, press the switch button, the ECU will collect relevant signals, then issue instructions to unlock, and then control the electric strut to extend to open the tailgate. When the user hopes to close the tailgate, press the switch button, the ECU will also collect relevant signals, then issue instructions to control the electric strut to shorten. After the closing action is completed, it will be locked. It can be seen that the mechanism that provides the opening and closing actions for the tailgate and enables the tailgate to hover at any angle is the electric strut. Whether the tailgate can hover at any angle depends on the magnitude of the damping force of the electric strut. However, for the existing structure of the electric strut, after the tailgate is opened to the preset angle, the ECU controls the motor to cut off power and stop outputting power, and the electric strut relies on the spring force to maintain the supporting force. Since after the tailgate is opened to the preset angle, once the gravity of the tailgate exceeds the spring force, the tailgate will compress the electric strut and cause it to retract. When the electric strut retracts, the screw of the electric strut will rotate together, making it difficult for the tailgate to accurately position at the opened angle, causing inconvenience to the user, and even causing the situation that the tailgate falls and injures the user.

[0004] The patent "An Electric Tailgate Support Rod" with the authorized publication number CN211500267U discloses an electric tailgate support rod, which solves the problem that the screw rotates due to the gravity of the tailgate when the motor stops by setting a set of inner ring and outer ring that form a friction fit as a friction resistance device to increase the resistance to prevent the screw from rotating when the motor stops, so that the electric strut will no longer be affected by the weight of the tailgate. However, the diameters of the inner ring and the outer ring are fixed, and after a period of mutual friction of the materials of the inner ring and the outer ring, the contact surface will gradually become smooth, and the friction resistance formed by the inner ring and the outer ring will decrease until it cannot provide sufficient friction resistance, resulting in the failure of the friction resistance device. The electric strut will still be affected by the weight of the tailgate and retract when the motor stops, causing inconvenience to the user and unable to effectively solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to address the corresponding deficiencies in the prior art and to provide an electric support rod for a car tailgate. By providing a clamping mechanism to increase the friction force, not only can the retraction of the telescopic tube be prevented and the rotation of the screw be avoided, but also the failure of the clamping mechanism due to friction loss after long-term use will not be caused. This effectively solves the problem that the electric support rod will retract due to the weight of the tailgate when the motor stops.

[0006] The objective of the present invention is achieved by adopting the following scheme: an electric support rod for a car tailgate comprises an outer tube, one end of the outer tube is fixedly connected to a first hinge seat, an inner cavity of the end of the outer tube is provided with an electric motor through a motor protection sleeve, a guide tube is provided in the inner hole of the other end of the outer tube, a screw is provided in the guide tube, the screw is connected to the motor through a reduction device, a telescopic tube is slidably fitted in the guide tube, one end of the telescopic tube is threadedly fitted with the screw through a nut, the other end of the telescopic tube is connected to a second hinge seat, the second hinge seat is fixedly connected to a sliding sleeve, the sliding sleeve is slidably fitted in the inner hole of the outer tube, a compression spring is sleeved between the guide tube and the outer tube, the extended end of the compression spring is located between the telescopic tube and the sliding sleeve, the screw is passed through The bearing is supported in the motor protection sleeve, one end of the bearing is axially positioned by a limiting boss arranged on the screw, and the other end is axially limited by a friction ring fixedly connected to the screw. A clamping mechanism for preventing the telescopic tube from retracting is arranged in the motor protection sleeve, and the clamping mechanism includes two bearings arranged opposite to each other and a force storage spring for applying pressure to the bearings. The two facing ends of the two bearings are provided with inferior arc grooves, and the inferior arc grooves of the two bearings correspond to the outer circle of the friction ring. The radius of the inferior arc groove is the same as the radius of the friction ring. Spring mounting holes are provided at opposite ends of the two bearings, one end of the force storage spring is located in the spring mounting hole, and the other end is against the motor protection sleeve. The inferior arc grooves of the two bearings form a friction fit with the boss on the screw under the action of the force storage spring.

[0007] The elastic force of the force storage spring is 30N to 80N, so that the screw rod is subjected to a rotation damping torque of 0.1N·m to 0.3N·m, that is, the electric strut is subjected to a damping force of 80N to 240N.

[0008] The bearing bush is made of wear-resistant resin material.

[0009] A smooth section is arranged between the limiting boss and the threaded section on the screw rod, a sealing ring is arranged between the smooth section and the guide tube, and the inner hole of the sealing ring forms a sealing fit with the outer circle of the smooth section.

[0010] The present invention includes the following beneficial effects: the screw is supported in the motor protection sleeve by a bearing, one end of the bearing is axially positioned by a limiting boss arranged on the screw, and the other end is axially limited by a friction ring fixedly connected to the screw, a clamping mechanism for preventing the telescopic tube from retracting is arranged in the motor protection sleeve, the clamping mechanism includes two bearings arranged opposite to each other and a force storage spring for applying pressure to the bearings, the two bearings are provided with inferior arc grooves at the opposite ends, the two bearings have inferior arc grooves corresponding to the outer circle of the friction ring, the radius of the inferior arc groove is the same as the radius of the friction ring, the opposite ends of the two bearings are provided with spring mounting holes, one end of the force storage spring is located in the spring mounting hole, and the other end is against the motor protection sleeve, and the inferior arc grooves of the two bearings form a friction fit with the boss on the screw under the action of the force storage spring.

[0011] Once the contact surface between the bearing and the friction ring on the screw is worn during long-term use, the elastic force of the force storage spring will push the bearing toward the screw to clamp the screw, and continue to maintain resistance, so that the function of the clamping mechanism will not fail.

[0012] The elastic force of the force storage spring is 30N to 80N, so that the screw rod is subjected to a rotational damping torque of 0.1N·m to 0.3N·m, that is, the electric strut is subjected to a damping force of 80N to 240N.

[0013] The bearing bush is made of wear-resistant resin material to provide sufficient friction.

[0014] A smooth section is provided between the limiting boss and the threaded section on the screw rod, and a sealing ring is provided between the smooth section and the guide tube, and the inner hole of the sealing ring forms a sealing fit with the outer circle of the smooth section. The sealing ring mainly plays a waterproof role, improves the waterproof performance of the electric strut, and ensures the normal operation of the motor in the outer tube.

[0015] The present invention is safe and reliable to use. The friction force is increased by the arranged clamping mechanism, which not only prevents the telescopic tube from retracting and avoids the screw rod from rotating, but also prevents the clamping mechanism from failing due to friction loss caused by long-term use. The present invention effectively solves the problem that the electric support rod will retract due to the influence of the weight of the tailgate when the motor stops. The present invention is suitable for opening and closing tailgates of different models and has a wide range of uses. The design of the car tailgate is no longer restricted by the electric support rod, which brings convenience to the tailgate design. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0018] Figure 3 It is a structural schematic diagram of the screw rod and the clamping mechanism in the present invention;

[0019] Figure 4 It is a schematic diagram of the structure of a bearing shell equipped with a force storage spring in the present invention. DETAILED DESCRIPTION

[0020] like Figures 1 to 4 As shown, an electric support rod for a car tailgate comprises an outer tube 1, one end of the outer tube 1 is fixedly connected to a first hinge seat 2, a motor 4 is arranged in the inner cavity of the end of the outer tube 1 through a motor protection sleeve 3, a guide tube 5 is arranged in the inner hole of the other end of the outer tube 1, a screw 6 is arranged in the guide tube 5, the screw 6 is connected to the motor 4 through a reduction device 7, a telescopic tube 8 is slidably fitted in the guide tube 5, one end of the telescopic tube 8 is threadedly fitted with the screw 6 through a nut 9, the other end of the telescopic tube 8 is connected to a second hinge seat 10, the second hinge seat 10 is fixedly connected to a sliding sleeve 11, the sliding sleeve 11 is slidably fitted In the inner hole of the outer tube 1, a compression spring 12 is sleeved between the guide tube 5 and the outer tube 1, and the extended end of the compression spring 12 is located between the telescopic tube 8 and the sliding sleeve 11. The screw 6 is supported in the motor protection sleeve 3 through a bearing 13, one end of the bearing 13 is axially positioned by a limiting boss 17 provided on the screw 6, and the other end is axially limited by a friction ring 14 fixedly connected to the screw 6. A smooth section 19 is provided between the limiting boss 17 on the screw 6 and the threaded section, and a sealing ring 18 is provided between the smooth section 19 and the guide tube 5, and the inner hole of the sealing ring 18 forms a sealing fit with the outer circle of the smooth section 19. The sealing ring 18 mainly plays a waterproof role, improves the waterproof performance of the electric strut, and ensures the normal operation of the motor 4 in the outer tube 1. A clamping mechanism for preventing the telescopic tube 8 from retracting is arranged in the motor protection cover 3, and the clamping mechanism includes two bearings 15 arranged opposite to each other and a force storage spring 16 for applying pressure to the bearings 15. In this embodiment, the material of the force storage spring 16 is spring steel, and the elastic force of the force storage spring 16 is 30N to 80N, so that the screw rod 6 is subjected to a rotation damping torque of 0.1N·m to 0.3N·m, that is, the electric strut is subjected to a damping force of 80N to 240N. The bearing 15 is made of wear-resistant resin material to provide sufficient friction. The two bearing shells 15 are provided with inferior arc grooves 20 at the facing ends, and the inferior arc grooves 20 of the two bearing shells 15 correspond to the outer circle of the friction ring 14. The radius of the inferior arc groove 20 is the same as the radius of the friction ring 14. The two bearing shells 15 are provided with spring mounting holes at the opposite ends, and one end of the force storage spring 16 is located in the spring mounting hole, and the other end is against the motor protection cover 3. Under the action of the force storage spring 16, the inferior arc grooves 20 of the two bearing shells 15 form a friction fit with the boss 14 on the screw 6.

[0021] During use, the second hinge seat 10 of the electric strut is fixedly connected to the tailgate, and the first hinge seat 2 is fixedly connected to the vehicle body. When opening the tailgate, the driving force of the motor 4 is much greater than the resistance of the clamping mechanism. The motor 4 operates to drive the screw rod 6 to rotate normally. Since the nut 9 is circumferentially fixed and cannot rotate circumferentially, under the drive of the screw rod 6, the nut 9 that is in threaded engagement with the screw rod 6 will axially extend. The telescopic tube 8 fixedly connected to the nut 9 causes the second hinge seat 10 to push the tailgate to open the vehicle tailgate. After the vehicle tailgate is opened, the motor 4 stops working. The gravity of the tailgate will cause the screw rod 6 to have a tendency to rotate. At this time, the stopped motor 4 will generate a torque that hinders the rotation of the screw rod 6, and the bearing bush 15 of the clamping mechanism will also generate a frictional resistance that hinders the rotation of the screw rod 6. Under the combined action of the resistance of the motor 4 and the resistance of the clamping mechanism, the possibility of the screw rod 6 rotating due to the gravity of the tailgate when stopped is eliminated, so that the electric strut will no longer be affected by the weight of the tailgate, improving the working stability of the electric strut and ensuring the effective support of the electric strut for the tailgate. When closing the tailgate, the motor 4 operates, and the motor shaft rotates in the reverse direction to make the nut 6 drive the telescopic tube 8 to retract, realizing the closing of the tailgate.

[0022] In summary, the clamping mechanism inside the electric strut not only needs to ensure that when opening the tailgate, the driving force of the motor 4 is much greater than the damping force received by the electric strut, but also must ensure that when the motor 4 stops working after the vehicle tailgate is opened, the torque generated by the stopped motor 4 that hinders the rotation of the screw rod 6 and the frictional resistance generated by the bearing bush 15 of the clamping mechanism that hinders the rotation of the screw rod 6 enable the damping force received by the electric strut to eliminate / balance the rotation of the screw rod 6 due to the gravity of the tailgate when the motor 4 stops.

[0023] Once the contact surface between the bearing bush 15 and the friction ring 14 on the screw rod 6 wears during long-term use of the present invention, the elastic force of the energy storage spring 16 will push the bearing bush 15 towards the screw rod 6 to clamp the screw rod 6 and continue to maintain the resistance, so that the function of the clamping mechanism will not fail.

[0024] The present invention is safe and reliable in use. By setting the clamping mechanism, sufficient frictional resistance is increased. It can not only prevent the telescopic tube from retracting when the electric strut stops extending, avoiding the rotation of the screw rod 6, but also ensure that the function of the clamping mechanism will not fail due to the loss caused by friction during long-term use of the electric strut, improving the user's satisfaction. Moreover, it can also be applied to the opening and closing of the tailgates of different vehicle models, with a wide range of applications. The design of the vehicle tailgate is no longer restricted by the electric strut, bringing convenience to the tailgate design.

[0025] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications made by those skilled in the art without departing from the spirit of the present invention fall within the protection scope of the present invention.

Claims

1. An electric strut for a vehicle tailgate, comprising an outer tube (1), one end of the outer tube (1) is fixedly connected to a first hinge seat (2), a motor (4) is arranged in the inner cavity of this end of the outer tube (1) through a motor protection sleeve (3), a guide tube (5) is arranged in the inner hole of the other end of the outer tube (1), a screw rod (6) is arranged in the guide tube (5), the screw rod (6) is connected to the motor (4) through a reduction device (7), a telescopic tube (8) is slidably fitted in the guide tube (5), one end of the telescopic tube (8) is threadedly fitted with the screw rod (6) through a nut (9), the other end of the telescopic tube (8) is connected to a second hinge seat (10), the second hinge seat (10) is fixedly connected to a sliding sleeve (11), the sliding sleeve (11) is slidably fitted in the inner hole of the outer tube (1), a compression spring (12) is sleeved between the guide tube (5) and the outer tube (1), and the extending end of the compression spring (12) is located between the telescopic tube (8) and the sliding sleeve (11), characterized in that: The screw rod (6) is supported in the motor protection sleeve (3) via a bearing (13); one end of the bearing (13) is axially positioned by a limiting boss (17) provided on the screw rod (6); the other end is axially limited by a friction ring (14) fixedly connected to the screw rod (6); a clamping mechanism for preventing the telescopic tube (8) from retracting is provided in the motor protection sleeve (3); the clamping mechanism comprises two bearing bushes (15) arranged opposite to each other and a force storage spring (16) for applying pressure to the bearing bushes (15); the two bearing bushes (15) are arranged opposite to each other. The ends of the two bearings (15) are provided with inferior arc grooves (20), the inferior arc grooves (20) of the two bearing shells (15) correspond to the outer circle of the friction ring (14), the radius of the inferior arc groove (20) is the same as the radius of the friction ring (14), the opposite ends of the two bearing shells (15) are provided with spring mounting holes, one end of the force storage spring (16) is located in the spring mounting hole, and the other end abuts against the motor protection sleeve (3), and the inferior arc grooves (20) of the two bearing shells (15) form a friction fit with the boss (14) on the screw rod (6) under the action of the force storage spring (16); The elastic force of the force storage spring (16) is 30N to 80N; The bearing bush (15) is made of wear-resistant resin material; A smooth section (19) is provided between the limiting boss (17) and the threaded section on the screw rod (6), a sealing ring (18) is provided between the smooth section (19) and the guide tube (5), and an inner hole of the sealing ring (18) and an outer circle of the smooth section (19) form a sealing fit.

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