Two-way extending linear actuator based on hollow and solid lead screw transmission

Abstract

The invention provides a two-way extending linear actuator based on hollow and solid lead screw transmission, and relates to the technical field of linear actuators, the two-way extending linear actuator comprises a driving supporting device, a first extending assembly and a second extending assembly, the first extending assembly and the second extending assembly are coaxial, and the first extending assembly and the second extending assembly are connected with the output end of the driving supporting device; the driving and supporting device is used for simultaneously driving the extending ends of the first extending assembly and the second extending assembly to extend and retract towards opposite directions; the first extending assembly comprises a hollow lead screw nut and a hollow lead screw, the second extending assembly comprises a solid lead screw nut and a solid lead screw, the hollow lead screw and the solid lead screw nut rotate in the same direction, and due to the fact that the rotating direction of the solid lead screw is opposite to the rotating direction of the hollow lead screw, the two ends of the linear driver can extend out at the same time. Therefore, the extending speed and the stroke of the linear driver are improved. The linear actuator is compact in structure and rapid in response, and can be suitable for working conditions with high speed requirements and large stroke requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of linear actuators, and in particular to a bidirectional extending linear actuator based on hollow-solid lead screw transmission. Background Art

[0002] The working stroke of conventional linear actuators is often limited by their dimensions. For applications requiring a larger working stroke, a larger linear actuator must be selected to ensure the desired dexterity within the mechanism's workspace. However, oversizing a linear actuator can lead to assembly difficulties and reduced component life. Therefore, in certain specific applications, the use of a multi-stage linear actuator is essential.

[0003] In order to increase the stroke of existing linear actuators, most of them use a multi-stage rod that is extended sequentially to increase the working stroke of the linear actuator. Although this method can significantly increase the stroke of the linear actuator, the speed of the linear actuator is not improved because the rods at each stage are extended sequentially. In addition, the large size of this type of linear actuator makes it difficult to install and use, and has certain limitations.

[0004] Therefore, it is very necessary to design a linear actuator that does not extend sequentially but can still improve its working stroke and working speed. It has certain practical value and research significance. Summary of the Invention

[0005] In response to the technical problems raised above, a bidirectional extending linear actuator based on a hollow-solid screw drive is provided. Without increasing the size specifications of the linear drive or slowing down the extension speed of the linear drive, the structure of the linear drive is simplified, making the bidirectional extending linear actuator better suitable for working conditions with large stroke requirements and fast speed requirements.

[0006] The technical means adopted in the present invention are as follows:

[0007] A bidirectional extending linear actuator based on a hollow-solid screw transmission includes: a driving support device, a first extending component and a second extending component, the first extending component and the second extending component are coaxially arranged, and the first extending component and the second extending component are both connected to the output end of the driving support device, and the driving support device is used to simultaneously drive the extending ends of the first extending component and the second extending component to extend and retract in opposite directions.

[0008] Furthermore, the driving support device includes a movable guide member, a screw support member, a transmission support device and a servo motor, the first extending assembly includes a hollow screw nut and a hollow screw, the second extending assembly includes a solid screw nut and a solid screw, and the movable guide member, screw support member, hollow screw nut, hollow screw, solid screw nut and solid screw are coaxial;

[0009] The transmission support device includes a transmission box and a transmission mechanism installed in the transmission box, the housing of the servo motor and the tail end of the screw support member are fixedly connected to the transmission box, the axis of the servo motor is parallel to the axis of the screw support member, the output end of the servo motor is connected to the transmission mechanism, and the transmission mechanism is fixedly connected to the hollow screw and the solid screw nut;

[0010] The movable guide member and the hollow lead screw nut are both placed in the lead screw support member, the movable guide member is slidably connected to the lead screw support member, one end of the movable guide member is fixedly connected to the hollow lead screw nut, and the other end can extend out of the lead screw support member;

[0011] The hollow screw nut and the hollow screw form a first spiral pair, one side of the hollow screw is located inside the movable guide member, and the other side is located inside the screw support member and the transmission box; and the front end of the solid screw nut is fixedly connected to the other tail end of the hollow screw, and the solid screw nut and the solid screw form a second spiral pair, one side of the solid screw is placed inside the hollow screw, and the other side can extend out of the transmission box; the first spiral pair and the second spiral pair have opposite rotation directions.

[0012] Furthermore, the transmission mechanism includes a driven wheel, a driving wheel and a screw nut support bearing, the output end of the servo motor is fixedly connected to the driving wheel, the driving wheel is arranged in the transmission box and is meshed and transmitted with the driven wheel, the interior of the driven wheel is fixedly connected to the tail end of the hollow screw and the solid screw nut, and the hollow screw and the solid screw nut are respectively rotationally connected to the transmission box through the screw nut support bearing.

[0013] Furthermore, the transmission box includes a front end cover, a transmission box body, a rear end cover and a locking nut, and the screw nut supporting bearing includes a first bearing and a second bearing;

[0014] The first bearing is rotatably connected to the hollow lead screw. The locking nut is located between the front end of the driven wheel and the first bearing. The locking nut and the hollow lead screw form a spiral pair and are used to axially fix the inner ring of the first bearing. The front end cover is fixedly connected between the lead screw support member and the transmission box body and is used to axially fix the outer ring of the first bearing.

[0015] The second bearing is rotatably connected to the tail end of the solid screw nut, and the rear end cover is located between the tail end of the driven wheel and the second bearing. The inner ring and outer ring of the second bearing are axially fixed respectively by the rear end cover and the transmission box body.

[0016] Furthermore, the transmission box includes a front end cover, a transmission box body, a rear end cover, a locking nut and an auxiliary end cover, and the screw nut support bearing includes a first bearing, a second bearing and a third bearing;

[0017] The first bearing and the third bearing are placed side by side and fit together and are both rotatably connected to the hollow screw. The locking nut is located between the front end of the driven wheel and the first bearing. The locking nut and the hollow screw form a spiral pair for axially fixing the inner ring of the first bearing; the front end cover and the auxiliary end cover are located between the screw support member and the transmission case body, one side of the front end cover is fixedly connected to the transmission case body, and the other side is fixedly connected to one side of the auxiliary end cover for axially fixing the outer ring of the first bearing; the other side of the auxiliary end cover is fixedly connected to the screw support member for axially fixing the outer ring of the third bearing;

[0018] The second bearing is rotatably connected to the tail end of the solid screw nut, and the rear end cover is located between the tail end of the driven wheel and the second bearing. The inner ring and outer ring of the second bearing are axially fixed respectively by the rear end cover and the transmission box body.

[0019] Furthermore, the end of the movable guide member away from the hollow screw nut can be connected to the connected member via a universal hinge, or can be rotatably connected to the connected member, or can be fixedly connected to the connected member;

[0020] The end of the solid lead screw away from the solid lead screw nut can be connected to the connected member via a universal hinge, or can be rotationally connected to the connected member; or can be fixedly connected to the connected member.

[0021] Furthermore, the hollow screw is circumferentially fixed to the driven wheel by a flat key, and also transmits torque between the hollow screw and the driven wheel;

[0022] The solid screw nut is circumferentially fixed to the driven wheel through a flat key, and also transmits torque to the driven wheel.

[0023] Furthermore, a guide support device is installed on one end of the solid screw inside the hollow screw to ensure the guiding and rotation accuracy of the hollow screw.

[0024] Furthermore, the guide support device includes a bearing, a copper sleeve and a hole retaining ring. The bearing and the solid screw are rotatably connected. The inner ring of the copper sleeve is in contact with the outer ring of the bearing and is rotatably connected. The outer ring of the copper sleeve is in contact with the inner ring of the hollow screw. The hole retaining ring is fixedly connected to the solid screw to achieve axial fixation of the bearing and the copper sleeve.

[0025] Furthermore, a corrugated tube is used to seal and dustproof the protruding portion of the solid lead screw, one end of the corrugated tube is fixedly connected to the transmission box, and the other end is fixedly connected to the head end of the solid lead screw.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The bidirectional extension linear actuator based on hollow and solid screw transmission provided by the present invention can further improve the extension range of the linear actuator on the basis of keeping the size specifications of the linear actuator unchanged and the installation conditions limited, due to the bidirectional extension of the hollow screw nut and the solid screw, so that it can meet more large-stroke working conditions.

[0028] 2. The bidirectional extension linear actuator based on a hollow and solid lead screw drive provided by this invention utilizes a single motor to simultaneously rotate the hollow lead screw and solid lead screw nut, thereby achieving bidirectional extension of the linear actuator. Compared to most previous multi-stage linear actuators, which extend the extension rods sequentially, this invention increases the linear actuator's travel range within the same timeframe, meeting the industry's demand for linear actuators that require rapid and continuous lifting and lowering operations.

[0029] 3. The present invention provides a bidirectional extension linear actuator based on hollow and solid screw transmission. The servo motor rotates the hollow screw and the solid screw nut through the transmission support device. Since the hollow screw and the solid screw rotate in opposite directions, the movable guide member and the solid screw will extend in opposite directions, thereby realizing the bidirectional extension of the overall linear drive.

[0030] 4. The bidirectional extension linear actuator based on hollow-solid screw transmission provided by the present invention has a compact structure and rapid response, making the linear drive suitable for working conditions requiring fast speed and large stroke. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0032] Figure 1 It is a schematic diagram of the overall structure of a bidirectional extending linear actuator based on hollow and solid lead screw transmission in a specific embodiment of the present invention.

[0033] Figure 2 It is a simplified cross-sectional structural diagram of a bidirectionally extending linear actuator in a specific embodiment of the present invention.

[0034] Figure 3 Schematic diagram of the cross-sectional structure of the bidirectionally extending linear actuator in Example 1 of the present invention.

[0035] Figure 4 Schematic diagram of the cross-sectional structure of the bidirectionally extending linear actuator in Example 2 of the present invention.

[0036] In the figure: 1. Movable guide member; 2. Screw support member; 3. Hollow screw nut; 4. Hollow screw; 5. Solid screw nut; 6. Solid screw; 7. Transmission support device; 701. Transmission box; 70101. Front cover; 70102. Transmission box body; 70103. Rear cover; 70104. Locking nut; 70105. Auxiliary end cover; 702. Driven pulley; 703. Driving pulley; 704. Screw nut support bearing; 70401. First bearing; 70402. Second bearing; 70403. Third bearing; 8. Servo motor. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] Unless otherwise specified, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0041] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0042] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0043] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] The present invention provides a bidirectional extending linear actuator based on hollow and solid screw transmission, such as Figure 1 and Figure 2 As shown, it includes a movable guide member 1, a screw support member 2, a hollow screw nut 3, a hollow screw 4, a solid screw nut 5, a solid screw 6, a transmission support device 7 and a servo motor 8;

[0046] like Figure 2 As shown, the movable guide member 1 is installed inside the screw support member 2 and is slidably connected to the screw support member 2, and the center lines of the two are collinear; the lower extending component (first extending component) is slidably connected to the screw support member 2 inside the screw support member 2, and the lower extending component includes a hollow screw nut 3 and a hollow screw 4, the tail end of the movable guide member 1 is fixedly connected to the hollow screw nut 3 (the hollow screw nut 3 is installed on the hollow screw 4 in a floating installation manner and is fixedly connected to the movable guide member 1), and the other end can be extended to the outside of the screw support member 2, and the center lines of the movable guide member 1 and the hollow screw nut 3 are collinear; the front side of the hollow screw 4 is located inside the movable guide member 1, and the axis of the hollow screw 4 is collinear with the center line of the movable guide member 1; the hollow screw nut 3 and the hollow screw 4 form a first spiral pair;

[0047] The upper extension assembly (second extension assembly) includes a solid screw nut 5 and a solid screw 6. The front end of the solid screw nut 5 is fixedly connected to the rear end of the hollow screw 4 and is fixedly installed with the hollow screw 4, and the axis of the solid screw nut 5 is collinear with the axis of the hollow screw 4. The front side of the solid screw 6 is installed inside the hollow screw 4, and its center line is collinear with the axis of the hollow screw 4. The solid screw nut 5 and the solid screw 6 form a second helical pair. The first helical pair and the second helical pair have opposite rotation directions. During the operation of the linear actuator, the hollow screw 4 and the solid screw nut 5 rotate in the same direction. Since the rotation direction of the solid screw 6 is opposite to that of the hollow screw 4, the two ends of the linear actuator will extend simultaneously, thereby increasing the extension speed and stroke of the linear actuator. The present invention has a compact structure and rapid response, making the linear actuator suitable for working conditions requiring fast speed and large stroke.

[0048] The transmission support device 7 includes a transmission box 701, a driven wheel 702, a driving wheel 703 and a screw nut support bearing 704; the tail side of the hollow screw 4 is located inside the screw support member 2 and the transmission box 701, and the tail side of the solid screw 6 can extend out of the transmission box 701; the tail end of the screw support member 2 is fixedly connected to the transmission box 701; the driven wheel 702 is fixedly connected to the tail end of the hollow screw 4 on which the solid screw nut 5 is installed, and the axes of the two are collinear; the tail end of the hollow screw 4 equipped with the solid screw nut 5 and the driven wheel 702 is arranged in the transmission box 701 and is supported by the screw nut support bearing 704. The driving wheel 703 is connected to the transmission case 701 for rotation. The solid lead screw nut 5 is also arranged in the transmission case 701 and is connected to the transmission case 701 for rotation via the lead screw nut support bearing 704. The driving wheel 703 is meshed and connected to the driven wheel 702 for transmission. The driving wheel 703 is arranged in the transmission case 701 and drives the driven wheel 702 to rotate. Its axis is parallel to the axis of the driven wheel 702. The interior of the driven wheel 702 is fixedly connected to the tail end of the hollow lead screw 4 and the solid lead screw nut 5. The driving wheel 703 is fixedly connected to the output shaft of the servo motor 8, and the axes of the two are collinear. The housing of the servo motor 8 is fixedly connected to the transmission case 701. The servo motor 8 rotates the hollow lead screw 4 and the solid lead screw nut 5 through the transmission support device 7. Since the hollow lead screw 4 and the solid lead screw 6 rotate in opposite directions, the movable guide member 1 and the solid lead screw 6 will extend in opposite directions, thereby realizing the bidirectional extension of the overall linear drive.

[0049] Preferably, if Figure 3As shown, the transmission box 701 includes a front end cover 70101, a transmission box body 70102, a rear end cover 70103 and a locking nut 70104; the screw nut supporting bearing 704 includes a first bearing 70401 and a second bearing 70402; the first bearing 70401 is rotationally connected to the hollow screw 4, and the axes of the two coincide; the locking nut 70104 is located between the front end of the driven wheel 702 and the first bearing 70401, and the locking nut 70104 and the hollow screw 4 form a spiral pair, which axially fixes the inner ring of the first bearing 70401; the front end cover 70101 is located between the screw guide member 2 and the transmission box body 70102, and is connected to the transmission box The housing 70102 is fixedly connected, with its center line being collinear with the axis of the first bearing 70401, and the outer ring of the first bearing 70401 is axially fixed; the second bearing 70402 is rotationally connected to the solid screw nut 5, with their axes coinciding; the rear end cover 70103 is located between the tail end of the driven wheel 702 and the second bearing 70402, with the axes of the second bearing 70402 and the rear end cover 70103 being collinear, and the inner ring and outer ring of the second bearing 70402 are axially fixed respectively by the rear end cover 70103 and the transmission housing 70102; the axial fixation of the driven wheel 702 is completed by the rear end cover 70103 and the transmission housing 70104.

[0050] Example 2

[0051] Different from Example 1, in this embodiment, Figure 4As shown, the transmission box 701 can be divided into a front end cover 70101, a transmission box body 70102, a rear end cover 70103, a locking nut 70104 and an auxiliary end cover 70105; the screw nut supporting bearing 704 includes a first bearing 70401, a second bearing 70402 and a third bearing 70403; the first bearing 70401 and the third bearing 70403 are placed side by side and are both rotatably connected to the hollow screw 4, and their axes coincide; the locking nut 70104 is located between the front end of the driven wheel 702 and the first bearing 70401, and the locking nut 70104 and the hollow screw 4 form a spiral pair, which engages with the first bearing 70 401 and the inner ring of the third bearing 70403 are axially fixed; the front end cover 70101 and the auxiliary end cover 70105 are located between the screw support member 2 and the transmission box body 70102, and the center line is collinear with the axis of the first bearing 70401 and the third bearing 70403. One side of the front end cover 70101 is fixedly connected to the transmission box body 70102, and the other side is fixedly connected to one side of the auxiliary end cover 70105, and at the same time, the outer ring of the first bearing 70401 is axially fixed; the other side of the auxiliary end cover 70105 is fixedly connected to the screw support member 2, and the outer ring of the third bearing 70403 is axially fixed. The second bearing 70402 is rotatably connected to the rear end of the solid lead screw nut 5. The rear end cap 70103 is located between the rear end of the driven pulley 702 and the second bearing 70402. The rear end cap 70103 and the transmission case 70102 respectively secure the inner and outer rings of the second bearing 70402 in the axial direction. Compared to the single-row bearing in Example 1, the double-row bearing in Example 2 offers greater stability and rigidity. In situations with heavy loads, the solution in Example 2 can be employed.

[0052] Preferably, the end of the movable guide member 1 away from the hollow screw nut 3 can be connected to the connected member through a universal hinge, or can be rotationally connected to the connected member, or can be fixedly connected to the connected member.

[0053] Preferably, the end of the solid screw 6 away from the solid screw nut 5 can be connected to the connected part through a universal hinge, or can be rotationally connected to the connected part; or can be fixedly connected to the connected part.

[0054] Preferably, the hollow screw 4 is circumferentially fixed to the driven wheel 702 by a flat key, and torque is also transmitted between the hollow screw 4 and the driven wheel 702 .

[0055] Preferably, the solid screw nut 5 is circumferentially fixed to the driven wheel 702 by a flat key, and torque is also transmitted between the solid screw nut 5 and the driven wheel 702 .

[0056] Preferably, a guide support device is installed on one end of the solid screw 6 inside the hollow screw 4 to ensure the guiding and rotation accuracy of the hollow screw 4.

[0057] Preferably, the guide support device includes a bearing, a copper sleeve and a hole retaining ring. The bearing and the solid screw 6 are rotationally connected, and their axes are collinear with the center line of the solid screw 6; the inner ring of the copper sleeve is in contact with the outer ring of the bearing and is rotationally connected, and their axes are collinear, and the outer ring of the copper sleeve is in contact with the inner ring of the hollow screw 4; the center line of the hole retaining ring is collinear with the center line of the solid screw 6, and it is fixedly connected to the solid screw 6 to achieve axial fixation of the bearing and the copper sleeve.

[0058] Preferably, a corrugated tube is used to seal and dustproof the protruding portion of the solid screw 6 , one end of the corrugated tube is fixedly connected to the transmission box 701 , and the other end is fixedly connected to the head end of the solid screw 6 .

[0059] The working principle of the present invention is as follows:

[0060] like Figure 2 As shown, the present invention is a bidirectional extending linear actuator based on hollow and solid lead screw transmission, wherein the movable guide member 1 is slidingly connected to the lead screw support member 2, and their center lines are collinear; the movable guide member 1 is fixedly connected to the hollow lead screw nut 3, and their center lines are collinear; the hollow lead screw 4 is located inside the movable guide member 1, and the axis of the hollow lead screw 4 is collinear with the center line of the movable guide member 1; the hollow lead screw nut 3 and the hollow lead screw 4 form a first spiral pair; the solid lead screw nut 5 is fixedly connected to the tail end of the hollow lead screw 4, and the axis of the solid lead screw nut 5 is collinear with the axis of the hollow lead screw 4; the solid lead screw 6 is installed inside the hollow lead screw 4, and its center line is collinear with the axis of the hollow lead screw 4, and a second spiral pair is formed with the solid lead screw nut 5 and the solid lead screw 6 through the solid lead screw nut 5; the first spiral pair and the second spiral pair have opposite rotation directions.

[0061] The servo motor 8 rotates the hollow screw 4 and the solid screw nut 5 through the transmission support device 7. Since the hollow screw 4 and the solid screw 6 rotate in opposite directions, the movable guide member 1 and the solid screw 6 will extend in opposite directions, thereby realizing bidirectional extension of the overall linear drive.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bidirectional extension linear actuator based on hollow and solid screw transmission, characterized in that: include: A driving support device, a first extending component and a second extending component, wherein the first extending component and the second extending component are coaxially arranged, and the first extending component and the second extending component are both connected to the output end of the driving support device, and the driving support device is used to simultaneously drive the extending ends of the first extending component and the second extending component to extend and retract in opposite directions.

2. The bidirectional extension linear actuator based on hollow-solid screw transmission according to claim 1 is characterized in that: The driving support device comprises a movable guide member (1), a screw support member (2), a transmission support device (7) and a servo motor (8); the first extending assembly comprises a hollow screw nut (3) and a hollow screw (4); the second extending assembly comprises a solid screw nut (5) and a solid screw (6); the movable guide member (1), the screw support member (2), the hollow screw nut (3), the hollow screw (4), the solid screw nut (5) and the solid screw (6) are coaxial; The transmission support device (7) includes a transmission box (701) and a transmission mechanism installed in the transmission box (701); the housing of the servo motor (8) and the tail end of the screw support member (2) are fixedly connected to the transmission box (701); the axis of the servo motor (8) is parallel to the axis of the screw support member (2); the output end of the servo motor (8) is connected to the transmission mechanism; and the transmission mechanism is fixedly connected to the hollow screw (4) and the solid screw nut (5); The movable guide member (1) and the hollow lead screw nut (3) are both placed in the lead screw support member (2), the movable guide member (1) is slidably connected to the lead screw support member (2), one end of the movable guide member (1) is fixedly connected to the hollow lead screw nut (3), and the other end can extend out of the lead screw support member (2); The hollow lead screw nut (3) and the hollow lead screw (4) form a first helical pair, one side of the hollow lead screw (4) is located inside the movable guide member (1), and the other side is located inside the lead screw support member (2) and the transmission box (701); and the front end of the solid lead screw nut (5) is fixedly connected to the other end of the hollow lead screw (4), and the solid lead screw nut (5) and the solid lead screw (6) form a second helical pair, one side of the solid lead screw (6) is placed inside the hollow lead screw (4), and the other side can extend out of the transmission box (701); the first helical pair and the second helical pair have opposite rotation directions.

3. The bidirectional extension linear actuator based on hollow-solid screw transmission according to claim 2 is characterized in that: The transmission mechanism comprises a driven wheel (702), a driving wheel (703) and a screw nut support bearing (704); the output end of the servo motor (8) is fixedly connected to the driving wheel (703); the driving wheel (703) is arranged in a transmission box (701) and is meshed and transmission-connected with the driven wheel (702); the interior of the driven wheel (702) is fixedly connected to the tail end of the hollow screw (4) and the solid screw nut (5); the hollow screw (4) and the solid screw nut (5) are rotationally connected to the transmission box (701) via the screw nut support bearing (704) respectively.

4. The bidirectional extension linear actuator based on hollow-solid screw transmission according to claim 3 is characterized in that: The transmission box (701) includes a front end cover (70101), a transmission box body (70102), a rear end cover (70103) and a locking nut (70104); the lead screw nut support bearing (704) includes a first bearing (70401) and a second bearing (70402); The first bearing (70401) is rotatably connected to the hollow lead screw (4); the locking nut (70104) is located between the front end of the driven wheel (702) and the first bearing (70401); the locking nut (70104) and the hollow lead screw (4) form a spiral pair and are used to axially fix the inner ring of the first bearing (70401); the front end cover (70101) is fixedly connected between the lead screw support member (2) and the transmission box body (70102) and is used to axially fix the outer ring of the first bearing (70401); The second bearing (70402) is rotatably connected to the tail end of the solid screw nut (5), and the rear end cover (70103) is located between the tail end of the driven wheel (702) and the second bearing (70402). The inner ring and outer ring of the second bearing (70402) are axially fixed by the rear end cover (70103) and the transmission box body (70102).

5. The bidirectional extension linear actuator based on hollow-solid screw transmission according to claim 3 is characterized in that: The transmission box (701) includes a front end cover (70101), a transmission box body (70102), a rear end cover (70103), a locking nut (70104) and an auxiliary end cover (70105); the screw nut support bearing (704) includes a first bearing (70401), a second bearing (70402) and a third bearing (70403); The first bearing (70401) and the third bearing (70403) are placed side by side and are both rotatably connected to the hollow screw (4). The locking nut (70104) is located between the front end of the driven wheel (702) and the first bearing (70401). The locking nut (70104) and the hollow screw (4) form a spiral pair for axially fixing the inner ring of the first bearing (70401). The front end cover (70101) and the auxiliary end cover (70105) are located Between the screw support member (2) and the transmission case (70102), one side of the front end cover (70101) is fixedly connected to the transmission case (70102), and the other side is fixedly connected to one side of the auxiliary end cover (70105), for axially fixing the outer ring of the first bearing (70401); the other side of the auxiliary end cover (70105) is fixedly connected to the screw support member (2), for axially fixing the outer ring of the third bearing (70403); The second bearing (70402) is rotatably connected to the tail end of the solid screw nut (5), and the rear end cover (70103) is located between the tail end of the driven wheel (702) and the second bearing (70402). The inner ring and outer ring of the second bearing (70402) are axially fixed by the rear end cover (70103) and the transmission box body (70102).

6. The bidirectional extension linear actuator based on hollow and solid screw transmission according to claim 1, characterized in that: The end of the movable guide member (1) away from the hollow screw nut (3) can be connected to the connected member via a universal hinge, or can be rotatably connected to the connected member, or can be fixedly connected to the connected member; The end of the solid lead screw (6) away from the solid lead screw nut (5) can be connected to the connected part via a universal hinge, or can be rotationally connected to the connected part; or can be fixedly connected to the connected part.

7. The bidirectional extension linear actuator based on hollow-solid screw transmission according to claim 2, characterized in that: The hollow screw (4) is circumferentially fixed to the driven wheel (702) by a flat key, and also transmits torque to the driven wheel (702). The solid screw nut (5) is circumferentially fixed to the driven wheel (702) via a flat key, and also transmits torque to the driven wheel (702).

8. The bidirectional extension linear actuator based on hollow-solid screw transmission according to claim 2, characterized in that: A guide support device is installed on one end of the solid screw (6) inside the hollow screw (4) to ensure the guidance and rotation accuracy of the hollow screw (4).

9. The bidirectional extension linear actuator based on hollow and solid screw transmission according to claim 8, characterized in that: The guide support device includes a bearing, a copper sleeve and a hole retaining ring, the bearing and the solid screw (6) are rotatably connected, the inner ring of the copper sleeve is in contact with the outer ring of the bearing and is rotatably connected, the outer ring of the copper sleeve is in contact with the inner ring of the hollow screw (4), and the hole retaining ring is fixedly connected to the solid screw (6), thereby realizing axial fixation of the bearing and the copper sleeve.

10. The bidirectional extension linear actuator based on hollow-solid screw transmission according to claim 2, characterized in that: A corrugated tube is used to seal and dustproof the extended portion of the solid lead screw (6); one end of the corrugated tube is fixedly connected to the transmission box (701), and the other end is fixedly connected to the head end of the solid lead screw (6).

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