An electric push rod that only pushes but does not pull

Abstract

The present invention discloses an electric push rod that can only push but not pull, and belongs to the technical field of mechanical device transmission. The electric push rod in the present invention comprises a driving motor, an outer tube fixedly connected to the driving motor, and an inner tube sleeved in the outer tube. The outer tube is also provided with a screw that rotates under the drive of the driving motor and a nut sleeved on the screw and moving along the axial direction of the screw. A connecting sleeve is provided on the inner tube, and the connecting sleeve comprises a first connecting part fixedly connected to the inner tube, a second connecting part used for slidingly sleeved on the nut, and a step part connecting the first connecting part and the second connecting part. The connecting sleeve bears the axial force on the nut through the step part. The electric push rod has strong controllability, high safety, energy saving and environmental protection, and high stability.

Description

[Technical field]

[0001] The invention relates to the technical field of mechanical device transmission, and in particular to an electric push rod that can only push but not pull. [Background technology]

[0002] Electric linear actuator, also known as linear drive, is a linear actuator mainly composed of motor push rod and control device. It can be used as an actuator in various simple or complex process flows to achieve remote control, centralized control or automatic control. It is mainly used as a motion drive unit in industries such as household appliances, kitchen utensils, medical equipment and automobiles. The electric linear actuator has exquisite design, small size, high precision, good self-locking and sanitation. The structure of the current electric linear actuator specifically includes a drive motor, a sleeved outer tube and an inner tube, a threaded screw and a nut. Its working principle is that the motor is driven by a gear or a turbine. After the worm gear is decelerated, it drives the lead screw to rotate, causing the nut to move on the lead screw along the axial direction of the lead screw, driving the inner tube connected to the nut to expand and contract, and converting the rotational motion of the motor into linear motion. The forward and reverse rotation of the motor is used to complete the push rod action, thereby driving the push and pull of the external movable platform connected to it. Therefore, the inner tube expands and contracts closely following the movement of the nut. When the driving motor reverses to drive the inner tube to retract, it will not stop when it encounters foreign objects, which can easily cause damage to objects or human body injuries. Especially for young children who are more curious and like to touch and explore with their hands, they can easily be pinched, which is very dangerous and has low safety performance. [Summary of the invention]

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and to design an energy-saving, environmentally friendly, and highly stable electric push rod that only pushes but does not pull.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A push rod that only pushes but does not pull, the electric push rod comprising a driving motor, an outer tube fixedly connected to the driving motor and an inner tube sleeved in the outer tube, the outer tube also comprising a screw that rotates under the drive of the driving motor and a nut sleeved on the screw and moving along the axial direction of the screw, the inner tube being provided with a connecting sleeve, the connecting sleeve comprising a first connecting portion fixedly connected to the inner tube, a second connecting portion for slidingly sleeved on the nut and a step portion connecting the first connecting portion and the second connecting portion, the connecting sleeve bearing the axial force on the nut through the step portion.

[0006] Beneficial effects of the invention:

[0007] 1. When the driving motor rotates forward, the driving screw rotates, thereby driving the nut to move forward and upward. Since the inner tube is fixedly connected to the connecting sleeve, and the connecting sleeve is supported by the nut, the connecting sleeve is lifted by the nut, driving the inner tube to extend forward, lifting the external movable platform to move forward and upward. When the driving motor is reversed, the driving screw rotates in the opposite direction. Since the nut is slidably connected to the second connecting part of the connecting sleeve, the nut moves backward and downward alone without driving the connecting sleeve and the inner tube to move. If the external movable platform needs to retreat or descend, the inner tube is manually retracted by using its own gravity and external force. If foreign objects are encountered during the descent, it can stop at any time. The controllability is strong, which greatly reduces the possibility of damage to objects or human body, and improves the safety performance of the entire movable device.

[0008] 2. Since the nut and the second connecting part of the connecting sleeve do not adopt the traditional threaded fixed connection, but adopt a sliding connection that is easy to move relative to each other, when the electric push rod is assembled on the external movable platform on the ground, if the distance between the external fasteners connected to the two ends of the screw rod and the length of the screw rod itself are not suitable, the inner tube can be manually pulled, and the length of the electric push rod can be adjusted by sliding the second connecting part of the connecting sleeve, so that the installation is easier to achieve, and the required distance can be adjusted at any time according to the needs. The operation is convenient and the adjustment accuracy is high. At the same time, there is no need to start the motor to adjust the length of the electric push rod, which is energy-saving and environmentally friendly.

[0009] 3. The inner tube in this solution is connected to the nut through a connecting sleeve. Compared with the inner tube end being directly connected to the nut, the connecting sleeve has the function of guiding and positioning the inner tube when it moves on the nut, thereby improving the stability of the inner tube during movement and preventing swinging and shaking.

[0010] Preferably, a transition thread sleeve is provided between the second connecting portion and the nut, the inner wall of the transition thread sleeve is threadedly connected to the outer wall of the nut, the outer wall of the transition thread sleeve is slidingly connected to the inner wall of the second connecting portion, and the connecting sleeve is at least partially supported on the transition thread sleeve through the step portion.

[0011] Preferably, the connecting sleeve is entirely supported on the transition threaded sleeve via the step portion.

[0012] In the prior art, the axial load force is mainly concentrated on the threads at the front end of the nut. The front end threads and the screw rod are too tightly engaged, and the friction force is too large, causing the nut and the screw rod to get stuck and moving with difficulty. When the axial load-bearing force is too large, the front end threads will also be broken, increasing the replacement frequency and cost. The rear end threads and the screw rod threads are separated and not fitted, causing the nut to shake, thereby affecting the stability of the entire transmission mechanism. With the transition thread sleeve structure in this scheme, when the electric push rod pushes or supports the external movable platform, the axial load force borne on the inner tube is partially or completely transmitted to the transition thread sleeve through the step portion. Since the inner wall of the transition thread sleeve is connected to the outer wall of the nut by threads, the teeth on the transition thread sleeve are tightly matched, and the axial load-bearing force is transmitted and evenly distributed on the nut, so that the various threads on the inner side of the nut that cooperate with the screw rod are evenly stressed, each circle of threads on the nut can be tightly engaged with the screw rod, and the movement is also more stable and smooth.

[0013] Preferably, the nut includes a shoulder surface, and the transition thread sleeve includes a transition thread sleeve body and a circular ring connected to the end of the transition thread sleeve body and arranged along the circumference of the transition thread sleeve body, and the circular ring is axially abutted against the shoulder surface of the nut.

[0014] Preferably, a guide surface is provided on the inner side of an end surface of the second connecting portion away from the step portion.

[0015] Preferably, the connecting sleeve is axially spaced apart with a plurality of guide slider groups, each guide slider group comprises a plurality of guide sliders spaced apart along the circumferential direction, each guide slider group is axially aligned front to back, and the inner wall of the outer tube is provided with a slide groove for the guide slider to slide axially.

[0016] In the single-circle slider in the prior art, if the slider is too short, the stability of the inner tube will be affected; if the slider is too long, the production is difficult, the manufacturing is easy to deform, and the cost is high. In the present scheme, the multi-circle guide slider cooperates in the slide groove to limit the sliding of the inner tube in the outer tube, so that it can only move axially relative to each other and will not rotate circumferentially. Since the multi-circle guide slider group is arranged at intervals, the axial matching size of the inner tube and the outer tube is longer, and the relative movement is more stable. The installation position of each circle of sliders is the same, that is, the sliders are also aligned front and back in the axial direction, and an axial row of sliders is arranged in the same slide groove, which has a better guiding effect, and the thickness of each circle of sliders is moderate, which is easy to process. At the same time, the connecting sleeve is arranged in the outer tube through the multi-circle guide slider group and fixedly positioned circumferentially. Therefore, the transition thread sleeve is also axially positioned on the screw rod. If the sliding distance of the connecting sleeve is too large and it disengages from the transition thread sleeve, it can still slide back to the outer wall of the transition thread sleeve after being pushed back, and there will be no jamming phenomenon.

[0017] Preferably, the connecting sleeve is provided with a plurality of annular grooves at intervals in the axial direction, a clamping ring is provided in each annular groove, and a plurality of guide sliding blocks spaced apart in the circumferential direction are provided on the clamping ring.

[0018] Preferably, the first connecting portion is threadedly connected to the inner tube, and the axial inner tube is supported on the step portion.

[0019] These features and advantages of the invention will be disclosed in detail in the following specific embodiments and drawings.

Brief Description of the Drawings

[0020] The invention will be further described below with reference to the accompanying drawings:

[0021] Figure 1 It is a front view of the electric push rod of the present invention which only pushes but does not pull.

[0022] Figure 2 This is a schematic diagram of the exploded view of the electric push rod of the present invention which only pushes but does not pull.

[0023] Figure 3 This is a schematic diagram of the three-dimensional structure of the electric push rod of the present invention without the mounting shell and the outer tube.

[0024] Figure 4 This is a cross-sectional view of the electric push rod of the present invention that only pushes but does not pull.

[0025] Figure 5 for Figure 4 Enlarged view of point A in the middle.

[0026] Figure 6 It is a schematic diagram of the three-dimensional structure of the connecting sleeve of the present invention.

[0027] Figure 7 It is a schematic diagram of the three-dimensional structure of the guide slider assembly of the present invention.

[0028] Figure 8 It is a schematic diagram of the three-dimensional structure of the sealing ring of the present invention.

[0029] Fig. 9 for Figure 8 Enlarged view of point B in the middle.

[0030] Fig.10 It is a schematic diagram of the three-dimensional structure of the outer tube of the present invention.

[0031] Fig.11 It is a schematic diagram of the three-dimensional structure of the inner side of the upper shell of the present invention.

[0032] Fig.12 It is a schematic diagram of the three-dimensional structure of the inner side of the lower shell of the present invention. [Specific implementation method]

[0033] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise clearly specified.

[0036] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above", "above" or "above" a second feature may include the first feature being directly above and obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may include the first feature being directly below and obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0038] Example:

[0039] like Figures 1 to 12 As shown, an electric push rod that only pushes but does not pull, the electric push rod comprises a driving motor 1, an outer tube 2 fixedly connected to the driving motor 1 and an inner tube 3 sleeved in the outer tube 2, the outer tube 2 is also provided with a screw rod 4 that rotates under the drive of the driving motor 1 and a nut 5 sleeved on the screw rod 4 and moves along the axial direction of the screw rod 4, the driving motor 1 is connected to the screw rod 4 in a transmission manner, and a connecting sleeve 6 is provided on the inner tube 3, as shown in FIG. Figure 6 As shown, the connecting sleeve 6 includes a first connecting portion 601 fixedly connected to the inner tube 3, a second connecting portion 602 for slidingly sleeved on the nut 5, and a step portion 603 connecting the first connecting portion 601 and the second connecting portion 602. The connecting sleeve 6 bears the axial force on the nut 5 through the step portion 603.

[0040] When the driving motor 1 rotates forward, the driving screw 4 rotates, thereby driving the nut 5 to move forward and upward. Since the inner tube 3 is fixedly connected to the connecting sleeve 6, and the connecting sleeve 6 is supported on the nut 5, the connecting sleeve 6 is lifted by the nut 5, driving the inner tube 3 to extend forward, lifting the external movable platform to move forward and upward. When the driving motor 1 is reversed, the driving screw 4 rotates in the opposite direction. Since the nut 5 is slidingly connected to the second connecting part 602 of the connecting sleeve 6, the nut 5 moves backward and downward alone, and does not drive the connecting sleeve 6 and the inner tube 3 to move. If the external movable platform needs to retreat or descend, the inner tube 3 is manually retracted by using its own gravity and external force. If foreign objects are encountered during the descent, it can stop at any time. The controllability is strong, which greatly reduces the possibility of damage to objects or human body injury, and improves the safety performance of the entire movable device. Since the nut 5 and the second connection part 602 of the connection sleeve 6 do not adopt the traditional threaded fixed connection, but adopt the sliding connection that is easy to move relative to each other, when the electric push rod is assembled on the external movable platform on the ground, if the distance between the external hardware connected to the two ends of the screw rod 4 and the length of the screw rod 4 itself are not suitable, the inner tube 3 can be manually pulled, and the length of the electric push rod can be adjusted by sliding the second connection part 602 of the connection sleeve 6, so that it is easier to achieve installation, and the required distance can be adjusted at any time according to needs, which is convenient to operate and has high adjustment accuracy. At the same time, there is no need to turn on the motor to adjust the length of the electric push rod, which is energy-saving and environmentally friendly. The inner tube 3 in this embodiment is supported on the nut 5 through the connection sleeve 6. Compared with the end of the inner tube 3 directly supported on the nut 5, the connection sleeve 6 has the function of guiding and positioning the inner tube 3 when it moves on the nut 5, improving the stability of the inner tube 3 during the movement process and preventing swinging and shaking.

[0041] In order to facilitate assembly and processing, such as Figure 4 and Figure 5 As shown, in this embodiment, the preferred specific connection mode of the connecting sleeve 6 is that the first connecting portion 601 is threadedly connected to the inner tube 3 , and the axial inner tube 3 is supported on the step portion 603 .

[0042] It can be understood that the connecting sleeve 6 can be formed integrally with the inner tube 3 .

[0043] It is understandable that a hole enlarging process may also be used on the end of the inner tube 3 to enlarge the end so as to be slidably mounted on the nut 5 .

[0044] The inner tube 3 of the currently used electric push rod is fixedly connected to the nut 5 by the connecting sleeve 6. The axial load force is mainly concentrated on the front end of the internal thread 501 of the nut 5. The front end of the internal thread 501 of the nut 5 is too tightly held with the screw rod 4, and the friction force is too large, so that the nut 5 and the screw rod 4 are stuck, and it is difficult to move. When the axial load-bearing force is too large, it will also cause the front end of the internal thread 501 of the nut 5 to break, increasing the replacement frequency and cost. The rear end of the internal thread 501 of the nut 5 is separated and not fitted with the screw rod 4 thread, causing the nut 5 to shake, thereby affecting the stability of the entire transmission mechanism. In order to overcome the deficiencies in the prior art, Figure 2 , Figure 4 and Figure 5 As shown, a transition thread sleeve 7 is sleeved between the second connecting portion 602 and the nut 5, and the inner wall of the transition thread sleeve 7 is threadedly connected to the outer wall of the nut 5, and the outer wall of the transition thread sleeve 7 is slidably connected to the inner wall of the second connecting portion 602. The connecting sleeve 6 is at least partially borne on the transition thread sleeve 7 through the step portion 603. When the electric push rod pushes or supports the external movable platform, the axial load force borne on the inner tube 3 is partially or completely transmitted to the transition thread sleeve 7 through the step portion 603. Since the inner wall of the transition thread sleeve 7 is threadedly connected to the outer wall of the nut 5, the teeth on the transition thread sleeve 7 are tightly matched, and the axial bearing force is transmitted and evenly distributed on the nut 5, so that the various threads on the inner side of the nut 5 that cooperate with the screw rod 4 are evenly stressed, and each circle of thread on the nut 5 can be tightly engaged with the screw rod 4, and the movement is also more stable and smooth. In order to make the axial bearing force evenly dispersed on the nut 5, the step portion 603 can be designed to be narrower, so that the connecting sleeve 6 is completely borne on the transition thread sleeve 7 through the step portion 603.

[0045] In order to better support the lifting connection sleeve 6 and the inner tube 3 during the forward or upward movement, as shown in FIG. Figure 2 and Figure 5 As shown, the nut 5 includes a shoulder surface, the transition thread sleeve 7 includes a transition thread sleeve body and a circular ring connected to the end of the transition thread sleeve body and arranged along the circumference of the transition thread sleeve body, the circular ring axially abuts against the shoulder surface of the nut 5, and the aforementioned structure is adopted. When in use, the front end of the transition thread sleeve body 7 axially abuts against the step portion 603, and the circular ring of the transition thread sleeve 7 axially abuts against the shoulder surface of the nut 5. The contact area between the circular ring and the shoulder surface is large, so that the axial bearing force on the inner tube 3 is more effectively transmitted and then evenly distributed on the nut 5. In order to reduce the noise during the use of the electric push rod and try to achieve the standard of silence, the material of the nut is generally plastic.

[0046] The inner tube 3 is pulled out for a long distance, and the second connecting portion 602 needs to be slid back onto the transition thread sleeve 7, or when the second connecting portion 602 is assembled with the nut 5, the second connecting portion 602 needs to be slid onto the transition thread sleeve 7. In order to facilitate assembly, Figure 2 As shown, a guide surface 602a is provided on the inner side of the end surface of the second connecting portion 602 away from the step portion 603, and a matching guide surface for matching sliding can also be provided at the front end of the transition threaded sleeve 7 accordingly. The guide surface 602a plays a role of sliding guide, which is more conducive to the assembly and sliding of the second connecting portion 602, avoids direct collision, and makes the assembly and sliding smoother.

[0047] In the prior art, if the single-circle slider is too short, the stability of the inner tube 3 is affected. If the slider is too long, the production is difficult, the manufacturing is easy to deform, and the cost is high. In this embodiment, the connecting sleeve 6 is axially spaced with two or more circles of guide slider assemblies 8, each circle of guide slider assemblies 8 includes two or more guide sliders 8a distributed at intervals along the circumferential direction, and each circle of guide sliders 8a is axially aligned front and back. A slide groove 201 for the axial sliding of the guide slider 8a is provided on the inner wall of the outer tube 2. The guide slider 8a cooperates in the slide groove 201 to limit the sliding of the inner tube 3 in the outer tube 2, so that it can only move axially relative to each other and will not rotate circumferentially. The components 8 are arranged at intervals, so the axial matching dimensions of the inner tube 3 and the outer tube 2 are longer, and the relative movement is more stable. The installation positions of the guide sliders 8a of each circle are the same, that is, the guide sliders 8a are also aligned front and back in the axial direction. An axial row of sliders is arranged in the same slide groove 201, and the guiding effect is better. The thickness of each circle of the guide slider 8a is moderate, which is convenient for processing. At the same time, the connecting sleeve 6 is sleeved in the outer tube 2 through the multi-circle guide slider assembly 8 and fixed in position circumferentially. Therefore, the transition thread sleeve 7 is also positioned circumferentially by the nut 5. Therefore, if the sliding distance of the connecting sleeve 6 is too large and it is separated from the transition thread sleeve 7, it can still slide back to the outer wall of the transition thread sleeve 7 after being pushed back, and there will be no jamming phenomenon.

[0048] In order to facilitate the processing and assembly of the components, the guide slider 8a is more firmly connected to the connecting sleeve 6. Figure 6 As shown, the connecting sleeve 6 is provided with two or more annular grooves 604 in the axial direction, and each annular groove 604 is provided with a snap ring 8b. Figure 7 As shown, the retaining ring 8b is provided with two or more guide sliders 8a spaced apart along the circumferential direction. The sliders and the retaining ring 8b are integrally formed and are easy to assemble after injection molding. Of course, the guide sliders 8a can also be directly installed on the outer wall of the second connecting part 602.

[0049] In order to better protect the components in the electric push rod, such as Figure 1 , Figure 2 , Figure 4 , Fig.11 and Fig.12As shown, the electric push rod is also provided with a mounting shell 9 for receiving and connecting the drive motor 1, the transmission mechanism and other auxiliary devices to form a complete electric tool entity. The mounting shell 9 includes an upper shell 901 and a lower shell 902 that are detachably fixedly connected. Fig.11 and Fig.12 As shown, a sealing ring 10 is disposed between the upper shell 901 and the lower shell 902, and sealing ring mounting grooves 901a and 902a are disposed on the upper shell 901 and the lower shell 902. Figure 8 and Fig. 9 As shown, the sealing ring 10 is provided with two or more positioning structures 1001 for facilitating the assembly of the sealing ring 10. The positioning structures 1001 are spaced apart along the sealing ring 10, and positioning grooves cooperating with the positioning structures 1001 are provided at positions corresponding to the positioning structures 1001 on the sealing ring mounting grooves 901a and 902a.

[0050] When installing the sealing ring 10, first install the positioning device on the sealing ring 10 into the matching positioning groove to achieve installation positioning, and then install the other parts of the sealing ring 10 into the sealing ring installation grooves 901a and 902a. Since the positioning structures 1001 are distributed at intervals along the sealing ring 10, the sealing ring 10 between two adjacent positioning structures 1001 is a segmented sealing strip with a shorter distance. After the two ends are fixed, the segmented sealing strip has a small deformation amount and a low probability of being elongated or twisted. It is easier to cooperate with the sealing ring installation grooves 901a and 902a to achieve quick installation. After the corners and turning points are positioned and fixed, and the sealing ring 10 is of appropriate length, it will also become fitted and will not warp. By arranging the positioning structure 1001 on the sealing ring 10, quick installation of the sealing ring 10 is achieved, which is convenient to operate and has high assembly efficiency. The presence of the positioning structure 1001 makes the assembled sealing ring 10 more fit and firm, not easy to fall off, and has a good sealing effect.

[0051] The cross-section of the sealing ring 10 is a square structure. In order to reduce the difficulty of processing, facilitate production and installation, and save costs, the positioning structure 1001 is designed to be a protrusion protruding from the surface of the sealing ring 10. For example, the positioning structure 1001 is a protrusion protruding from at least one side of the sealing ring 10, or the positioning structure 1001 is an annular protrusion or a square protrusion protruding from the circumference of the sealing ring 10. The corresponding positioning groove can be directly widened or deepened on the basis of the sealing ring mounting grooves 901a and 902a themselves.

[0052] It can be understood that the positioning structure 1001 can also be a groove structure or a necked step structure recessed into the surface of the sealing ring.

[0053] It should be noted that the positioning structure can have multiple implementations, and this embodiment only preferentially lists several protrusion and groove structures therein. In other implementations of the invention, the positioning structure is not limited to these structures in this embodiment, and can also be other positioning structures with cross-sections different from the cross-section of the sealing surface itself. As long as the positioning function can be achieved, it falls within the protection scope of the present invention.

[0054] In order to fix the outer tube 2, one end of the outer tube 2 is fixed in the mounting shell 9. Fig.10 As shown, a positioning blind hole 202 is provided on the outer wall of the outer tube 2. Fig.11 and Fig.12 As shown, the inner wall of the upper shell 901 and the inner wall of the lower shell 902 are both provided with positioning ribs 901b, 902b that cooperate with the positioning blind hole 202. Figure 5 As shown, the positioning hole of the outer tube 2 is a blind hole provided on the outer wall of the outer tube 2, and the inner wall of the outer tube 2 is not processed, so the inner wall will not be damaged, so that there is no burr, flanging and other unevenness during through-hole processing, so the inner tube 3 can slide smoothly on the inner wall of the outer tube 2. At the same time, since the positioning hole is an ordinary round hole, it is easy to process and has a lower cost than the milled flat position or other special-shaped holes.

[0055] The above is only a specific embodiment of the invention, but the protection scope of the invention is not limited thereto. Those skilled in the art should understand that the invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the invention will be included in the scope of the claims.

Claims

1. An electric push rod that only pushes but does not pull, the electric push rod comprises a driving motor, an outer tube fixedly connected to the driving motor and an inner tube sleeved in the outer tube, the outer tube is also provided with a screw rod that rotates under the drive of the driving motor and a nut sleeved on the screw rod and moves along the axial direction of the screw rod, characterized in that: The inner tube is provided with a coupling sleeve, the coupling sleeve comprising a first coupling portion fixedly connected to the inner tube, a second coupling portion for slidingly sleeved on the nut, and a step portion connecting the first coupling portion and the second coupling portion, the coupling sleeve bearing the axial force on the nut through the step portion; the first coupling portion is threadedly connected to the inner tube, the coupling sleeve is provided with a plurality of guide slider groups at intervals in the axial direction, each guide slider group comprises a plurality of guide sliders spaced apart in the circumferential direction, each guide slider group is aligned front and back in the axial direction, and a slide groove for the guide slider to slide axially is provided on the inner wall of the outer tube; The coupling sleeve is provided with a plurality of annular grooves at intervals in the axial direction, each annular groove is provided with a clamping ring, and the clamping ring is provided with a plurality of guide sliding blocks distributed at intervals in the circumferential direction.

2. The push-only electric linear actuator according to claim 1, characterized in that: A transition thread sleeve is sleeved between the second connecting portion and the nut, the inner wall of the transition thread sleeve is threadedly connected to the outer wall of the nut, the outer wall of the transition thread sleeve is slidingly connected to the inner wall of the second connecting portion, and the connecting sleeve is at least partially supported on the transition thread sleeve through the step portion.

3. The push-only electric linear actuator according to claim 2, characterized in that: The connecting sleeve is completely supported on the transition thread sleeve through the step portion.

4. The push-only electric linear actuator according to any one of claims 2 or 3, characterized in that: The nut comprises a shoulder surface, and the transition thread sleeve comprises a transition thread sleeve body and a circular ring connected to the end of the transition thread sleeve body and arranged along the circumference of the transition thread sleeve body, wherein the circular ring is axially in contact with the shoulder surface of the nut.

5. The push-only electric linear actuator according to claim 1, characterized in that: A guide surface is provided on the inner side of an end surface of the second connecting portion away from the step portion.

6. The push-only electric linear actuator according to claim 1, characterized in that: The axial inner tube is supported on the step portion.

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