Transmission assembly of linear lifting device and linear lifting device

Abstract

The transmission assembly of the linear lifting device comprises a lead screw, a spline sleeve and a hollow hollow shaft arranged on the outer side of the lead screw in a sleeved mode, the spline sleeve is arranged on the outer side of the lead screw in a sleeved mode and rotates synchronously with the lead screw, the spline sleeve is connected with the inner wall of the hollow hollow shaft in a circumferential relative fixing and axial relative moving mode, and the spline sleeve is composed of two half sleeve bodies. The two half sleeve bodies are folded in the radial direction of the lead screw to form a spline sleeve, one of the inner wall of each half sleeve body and the peripheral side of the lead screw is provided with a positioning protrusion, the other one is provided with a positioning groove, and the positioning protrusions and the positioning grooves are matched in a radial inserting mode so that the half sleeve bodies can be axially fixed relative to the lead screw. The hollow shaft sleeves the spline housing and is used for limiting the positioning protrusions from being separated from the positioning grooves. According to the transmission assembly, the assembly process is simplified, and the integrity and the structural strength of the lead screw are guaranteed; the two half sleeve bodies can be directly folded or separated in the radial direction, and disassembly and assembly are convenient. In addition, the utility model further discloses a linear lifting device provided with the transmission assembly.

Description

[Technical Field]

[0001] This utility model relates to the field of linear lifting device technology, and in particular to the transmission assembly of linear lifting device and linear lifting device. [Background Technology]

[0002] The existing linear lifting device includes a transmission assembly and a sleeve assembly sleeved on the outside of the transmission assembly. The transmission assembly drives the sleeve assembly to extend and retract. The transmission assembly includes a lead screw, a spline sleeve, and a hollow shaft sleeved on the outside of the lead screw. The bottom end of the lead screw has a threaded hole extending along its axial direction. The spline sleeve is sleeved on the bottom end of the lead screw and rotates synchronously with the lead screw. The spline sleeve has a limiting step that abuts against the bottom end face of the lead screw. The limiting step forms a through hole. A screw passes through the through hole and is screwed into the threaded hole, thereby fixing the spline sleeve axially to the bottom end of the lead screw. This achieves axial relative fixation between the spline sleeve and the lead screw, while the spline sleeve and the inner wall of the hollow shaft maintain a circumferentially relatively fixed and axially relatively movable connection, so that the lead screw and the hollow shaft can extend and retract relative to each other along the axial direction. In existing technologies, the spline sleeve and lead screw are connected by screws to achieve axial relative fixation between the spline sleeve and the lead screw. However, under long-term vibration or alternating loads, the screws may loosen due to fretting wear of the threaded pair or attenuation of preload, leading to the risk of connection failure between the spline sleeve and the lead screw. In addition, a threaded hole needs to be made at the bottom end of the lead screw. The design of the threaded hole not only increases the machining difficulty of the lead screw, but also weakens the structural strength of the bottom end of the lead screw. Especially when subjected to large axial forces, stress concentration is prone to occur at the root of the thread, which may lead to breakage of the bottom end of the lead screw (especially for small-diameter lead screws). [Utility Model Content]

[0003] To address the shortcomings and deficiencies of the existing technology, this utility model provides a transmission assembly and linear lifting device for a linear lifting device. This eliminates the need for screws to connect the spline sleeve and the lead screw, thus simplifying the assembly process. Furthermore, the lead screw does not require machining of threaded holes, ensuring its integrity and structural strength. The two half-sleeves can be directly joined or separated radially, facilitating disassembly and assembly, and thus simplifying the maintenance or replacement of the spline sleeve.

[0004] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0005] The transmission assembly of the linear lifting device includes a lead screw, a spline sleeve, and a hollow shaft sleeved on the outside of the lead screw. The spline sleeve is sleeved on the outside of the lead screw and rotates synchronously with the lead screw. The spline sleeve and the inner wall of the hollow shaft are connected in a circumferentially fixed and axially movable manner, so that the lead screw and the hollow shaft can extend and retract relative to each other in the axial direction. The spline sleeve is composed of two half-sleeves, which are joined together radially along the lead screw to form the spline sleeve. One of the inner walls of the half-sleeves and the outer periphery of the lead screw is provided with a positioning protrusion, and the other is provided with a positioning groove. The positioning protrusion and the positioning groove are radially inserted to fix the half-sleeves axially relative to the lead screw. The hollow shaft is sleeved on the outside of the spline sleeve and is used to prevent the positioning protrusion from dislodging from the positioning groove.

[0006] In the transmission assembly of the above-mentioned linear lifting device, the lead screw includes a threaded section and a smooth shaft section connected along its axial direction, and the outer peripheral side of the smooth shaft section is provided with the positioning protrusion or positioning groove.

[0007] In the transmission assembly of the above-mentioned linear lifting device, the optical shaft section is provided with an annular positioning protrusion or an annular positioning groove, the outer periphery of the optical shaft section is provided with a non-cylindrical surface, and the inner wall of the spline sleeve has a non-circular inner wall adapted to the non-cylindrical surface.

[0008] In the transmission assembly of the aforementioned linear lifting device, the outer peripheral surface of the positioning protrusion forms the non-cylindrical surface, or the bottom surface of the positioning groove forms the non-cylindrical surface.

[0009] In the transmission assembly of the aforementioned linear lifting device, the optical axis section is provided with a plurality of circumferentially spaced positioning protrusions or positioning grooves.

[0010] In the transmission assembly of the above-mentioned linear lifting device, the optical shaft section is provided with a positioning protrusion. The positioning protrusion extends from the end face of the optical shaft section toward the threaded section. A slot is provided between the positioning protrusion and the threaded section. The inner wall of the half-body is provided with two inner shoulders that are axially spaced apart. The positioning groove is formed between the two inner shoulders. One inner shoulder abuts against the end face of the optical shaft section, and the other inner shoulder is inserted into the slot.

[0011] In the transmission assembly of the aforementioned linear lifting device, the optical shaft section is a solid rod-shaped structure.

[0012] In the transmission assembly of the above-mentioned linear lifting device, the outer peripheral surface of the spline sleeve is provided with a plurality of circumferentially spaced key teeth, and the outer peripheral surface of each half-sleeve is provided with at least one key tooth. The inner peripheral surface of the hollow shaft is provided with a keyway, and the key teeth are inserted into the keyway and can slide relative to the keyway along the axial direction of the lead screw.

[0013] In the transmission assembly of the above-mentioned linear lifting device, the insertion depth of the positioning protrusion and the positioning groove is H, the gap between the key teeth and the bottom wall of the keyway is H1, satisfying H1 < H; and / or, the gap between the inner circumferential surface of the hollow shaft and the outer circumferential surface of the spline sleeve is H2, satisfying H2 < H.

[0014] In addition, this utility model also discloses a linear lifting device, including a sleeve assembly, a transmission assembly, and a drive device. The drive device drives the sleeve assembly to extend and retract through the transmission assembly. The transmission assembly adopts the transmission assembly described in any of the above technical solutions. The drive device includes a motor, and the motor is coupled with the lead screw.

[0015] By adopting the above technical solution, this utility model has the following advantages:

[0016] 1. The spline sleeve in this utility model consists of two half-sleeves. During assembly, one half-sleeve is first fitted radially onto the outside of the lead screw, and the positioning protrusion is radially inserted into the positioning groove. The radial insertion of the positioning protrusion into the positioning groove fixes the half-sleeve axially relative to the lead screw. Then, the other half-sleeve is assembled in the same way. Thus, the two half-sleeves are joined radially along the lead screw to form the spline sleeve. The radial insertion of the positioning protrusion into the positioning groove achieves axial fixation of the spline sleeve on the lead screw. Then, while holding the spline sleeve to keep the two half-sleeves joined, the middle... A hollow shaft is sleeved on the outside of the spline sleeve. The hollow shaft covers the spline sleeve and restricts the positioning protrusion from disengaging from the positioning groove. This ensures the insertion and fit between the positioning protrusion and the positioning groove, thereby improving the reliability of the axial fixation of the spline sleeve relative to the lead screw. Therefore, this invention eliminates the need for screws to connect the spline sleeve and the lead screw, simplifying the assembly process. Furthermore, the lead screw does not require threaded holes, ensuring its integrity and structural strength. When the hollow shaft covering the spline sleeve is removed, the two half-sleeves can be directly radially joined or separated, making disassembly and assembly convenient and facilitating the maintenance or replacement of the spline sleeve.

[0017] 2. The lead screw includes a threaded section and a smooth shaft section connected along its axial direction. The outer periphery of the smooth shaft section is provided with a positioning protrusion or a positioning groove. Since the threaded section is used to drive the load lifting and lowering, while the surface of the smooth shaft section is flat, placing the positioning protrusion or positioning groove on the smooth shaft section can ensure the machining accuracy of the positioning protrusion or positioning groove, reduce assembly errors, and thus reduce the machining difficulty of the lead screw, while also avoiding occupying the threaded section and affecting the lifting stroke.

[0018] 3. The optical axis section is provided with an annular positioning protrusion or an annular positioning groove, and the outer circumference of the optical axis section is provided with a non-cylindrical surface. The inner wall of the spline sleeve has a non-circular inner wall that matches the non-cylindrical surface. The design of the annular positioning protrusion or annular positioning groove facilitates the half-sleeve fitting onto the outside of the lead screw, so that the positioning groove can quickly position and achieve a plug-in fit with the positioning protrusion. At the same time, the annular structure can also increase the mating area between the positioning groove and the positioning protrusion to improve the axial positioning effect of the spline sleeve. The fit between the non-cylindrical surface and the non-circular inner wall can achieve circumferential relative fixation between the spline sleeve and the optical axis section, so that the spline sleeve and the lead screw rotate synchronously. The structure is simple and eliminates the need for other connecting parts.

[0019] 4. The outer circumferential surface of the positioning protrusion is formed as a non-cylindrical surface, or the bottom surface of the positioning groove is formed as a non-cylindrical surface. Compared with setting a non-cylindrical surface on the outer circumference of the optical axis section outside the positioning protrusion or positioning groove, this technical solution can effectively shorten the axial length of the optical axis section, thereby further reducing the machining difficulty of the lead screw. In addition, the axial and circumferential relative fixation of the spline sleeve and the lead screw can be achieved simultaneously through the cooperation of the positioning protrusion and the positioning groove, achieving a dual-purpose effect.

[0020] 5. The optical axis section is provided with multiple circumferentially spaced positioning protrusions or positioning grooves. This design allows for simultaneous axial and circumferential relative fixation of the spline sleeve and the lead screw through the cooperation of the positioning protrusions and positioning grooves, achieving a dual-purpose effect.

[0021] 6. The optical axis section is provided with a positioning protrusion extending from the end face of the optical axis section towards the threaded section. A slot is provided between the positioning protrusion and the threaded section. The inner wall of the half-sleeve is provided with two axially spaced inner shoulders, forming a positioning groove between the two inner shoulders. One inner shoulder abuts against the end face of the optical axis section, and the other inner shoulder is inserted into the slot. Since the optical axis section of the existing screw-fixed spline sleeve usually has the above-mentioned positioning protrusion and slot, and the existing spline sleeve also has an inner shoulder abutting against the end face of the optical axis section, this technical solution only requires adding an inner shoulder to the slot inside the existing half-sleeve. The modification to the screw and spline sleeve is small, thereby reducing the modification cost.

[0022] 7. The optical axis section is a solid rod-shaped structure. This design ensures the integrity of the lead screw, thereby guaranteeing its structural strength and effectively preventing breakage of the optical axis section.

[0023] 8. The outer circumferential surface of the spline sleeve is provided with multiple circumferentially spaced key teeth, and the outer circumferential surface of each half-sleeve is provided with at least one of the key teeth. The inner circumferential surface of the hollow shaft is provided with a keyway, and the key teeth are inserted into the keyway and can slide relative to the keyway along the axial direction of the lead screw. This design ensures that both half-sleeves are circumferentially fixed to the hollow shaft through the insertion and engagement of the key teeth and the keyway, while the ability of the key teeth to slide relative to the keyway along the axial direction of the lead screw allows for axial relative movement between each half-sleeve and the hollow shaft, resulting in a relatively simple structure.

[0024] 9. The insertion depth of the positioning protrusion and the positioning groove is H, and the gap between the key teeth and the bottom wall of the keyway is H1, satisfying H1 < H; and / or, the gap between the inner circumferential surface of the hollow shaft and the outer circumferential surface of the spline sleeve is H2, satisfying H2 < H. This design can limit the radial outward movement range of the half-sleeve, thereby preventing the positioning protrusion from falling out of the positioning groove, thus ensuring the reliability of the insertion fit between the positioning protrusion and the positioning groove, so that the spline sleeve can always be fitted on the outside of the lead screw and fixed axially relative to the lead screw. [Attached Image Description]

[0025] Figure 1 This is an exploded view of the transmission assembly in Embodiment 1 of this utility model;

[0026] Figure 2 This is a schematic diagram of the structure of a portion of the lead screw in Embodiment 1 of this utility model;

[0027] Figure 3 This is a radial cross-sectional view of the hollow shaft in Embodiment 1 of this utility model;

[0028] Figure 4 This is a radial cross-sectional view of the hollow shaft, spline sleeve, and lead screw assembled in Embodiment 1 of this utility model;

[0029] Figure 5 This is a schematic diagram of the spline sleeve in Embodiment 1 of this utility model;

[0030] Figure 6 This is an exploded view of the spline sleeve in Embodiment 1 of this utility model;

[0031] Figure 7 This is a cross-sectional view of the transmission assembly in Embodiment 1 of this utility model, cut along the dividing plane of the two halves;

[0032] Figure 8 for Figure 7 A magnified view of part A in the diagram;

[0033] Figure 9 This is a cross-sectional view of the linear lifting device in Embodiment 3 of this utility model.

[0034] Icon labels:

[0035] 100. Transmission assembly; 110. Lead screw; 1101. Positioning protrusion; 1102. Slot; 111. Optical shaft section; 112. Threaded section; 120. Spline sleeve; 121. Half sleeve; 1210. Positioning groove; 1211. Inner shoulder; 122. Key tooth; 130. Hollow shaft; 131. Keyway; 1310. Keyway bottom wall; 140. First sleeve; 150. Second sleeve; 160. First transmission nut; 170. Second transmission nut; 200. Sleeve assembly; 210. Inner tube; 220. Middle tube; 230. Outer tube; 300. Bottom shell; 400. Fixing seat; 500. Base plate.

Detailed Implementation Methods

[0036] This utility model provides a transmission assembly for a linear lifting device, including a lead screw, a spline sleeve, and a hollow shaft sleeved on the outside of the lead screw. The spline sleeve is sleeved on the outside of the lead screw and rotates synchronously with the lead screw. The spline sleeve and the inner wall of the hollow shaft are connected in a circumferentially fixed and axially movable manner, so that the lead screw and the hollow shaft can extend and retract relative to each other in the axial direction. The spline sleeve is composed of two half-sleeves, which are joined together radially along the lead screw to form the spline sleeve. One of the inner walls of the half-sleeves and the outer periphery of the lead screw is provided with a positioning protrusion, and the other is provided with a positioning groove. The positioning protrusion and the positioning groove are radially inserted to fix the half-sleeves axially relative to the lead screw. The hollow shaft is sleeved on the outside of the spline sleeve and is used to prevent the positioning protrusion from dislodging from the positioning groove.

[0037] The spline sleeve of this invention consists of two half-sleeves. During assembly, one half-sleeve is first fitted radially onto the outside of the lead screw, with the positioning protrusion and positioning groove radially engaged. This radial engagement fixes the half-sleeve axially relative to the lead screw. The other half-sleeve is then assembled in the same manner. When the two half-sleeves are joined radially along the lead screw, a spline sleeve is formed. The axial fixation of the spline sleeve on the lead screw is achieved through the radial engagement of the positioning protrusion and positioning groove. Then, while holding the spline sleeve to maintain the joined state of the two half-sleeves, the hollow... The mandrel is sleeved on the outside of the spline sleeve. The hollow mandrel covers the spline sleeve and restricts the positioning protrusion from disengaging from the positioning groove. This ensures the insertion and fit between the positioning protrusion and the positioning groove, thereby improving the reliability of the axial fixation of the spline sleeve relative to the lead screw. Therefore, this invention eliminates the need for screws to connect the spline sleeve and the lead screw, simplifying the assembly process. Furthermore, the lead screw does not require threaded holes, ensuring its integrity and structural strength. When the hollow mandrel covering the spline sleeve is removed, the two half-sleeves can be directly radially joined or separated, making disassembly and assembly convenient and facilitating the maintenance or replacement of the spline sleeve.

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the terms "upper," "lower," "left," "right," "longitudinal," "lateral," "inner," "outer," "vertical," "horizontal," "top," and "bottom," etc., which indicate orientation or positional relationship, are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device / component referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0039] Example 1

[0040] Combination Figures 1 to 8 As shown, the transmission assembly 100 of the linear lifting device in this embodiment includes a lead screw 110, a spline sleeve 120, and a hollow shaft 130 sleeved on the outside of the lead screw 110. The spline sleeve 120 is sleeved on the outside of the lead screw 110 and rotates synchronously with the lead screw 110. The spline sleeve 120 and the inner wall of the hollow shaft 130 maintain a circumferentially fixed and axially movable connection, so that the lead screw 110 and the hollow shaft 130 can extend and retract relative to each other axially. The spline sleeve 120 is composed of two half-sleeves 121. The cutting surface of 1 extends along the axial direction of the lead screw 110. The two half-sleeves 121 are joined together radially along the lead screw 110 to form a spline sleeve 120. The inner walls of the two half-sleeves 121 are provided with positioning grooves 1210. The outer periphery of the lead screw 110 is provided with positioning protrusions 1101. The positioning protrusions 1101 and the positioning grooves 1210 are radially inserted to fix the half-sleeves 121 axially relative to the lead screw 110. The hollow shaft 130 is sleeved on the outside of the spline sleeve 120 and is used to restrict the positioning protrusions 1101 from falling out of the positioning grooves 1210.

[0041] In this embodiment, when assembling the spline sleeve 120, one half-sleeve 121 is first radially fitted onto the outside of the lead screw 110, and the positioning protrusion 1101 is radially inserted into the positioning groove 1210. This radial insertion of the positioning protrusion 1101 into the positioning groove 1210 fixes the half-sleeve 121 axially relative to the lead screw 110. Then, the other half-sleeve 121 is assembled in the same manner. Thus, the two half-sleeves 121 are radially joined together along the lead screw 110 to form the spline sleeve 120. The radial insertion of the positioning protrusion 1101 into the positioning groove 1210 achieves axial fixation of the spline sleeve 120 on the lead screw 110. Then, while holding the spline sleeve 120 to maintain the joined state of the two half-sleeves 121, the hollow... The mandrel 130 is sleeved on the outside of the spline sleeve 120. The hollow mandrel 130 covers the spline sleeve 120, which prevents the positioning protrusion 1101 from disengaging from the positioning groove 1210. This ensures the insertion and engagement of the positioning protrusion 1101 and the positioning groove 1210, thereby improving the reliability of the axial fixation of the spline sleeve 120 relative to the lead screw 110. Thus, in this embodiment, there is no need to connect the spline sleeve 120 and the lead screw 110 with screws, which simplifies the assembly process. Furthermore, the lead screw 110 does not need to be machined with threaded holes, thus ensuring the integrity and structural strength of the lead screw 110. When the hollow mandrel 130 is removed from covering the spline sleeve 120, the two half-sleeves 121 can be directly radially closed or separated, which is convenient for disassembly and assembly, and thus facilitates the maintenance or replacement of the spline sleeve 120.

[0042] Specifically, in this embodiment, the lead screw 110 includes an optical shaft section 111 and a threaded section 112 connected along the axial direction of the lead screw 110. One axial end of the optical shaft section 111 is connected to one axial end of the threaded section 112. Preferably, the optical shaft section 111 and the threaded section 112 are integrally machined, and the optical shaft section 111 is a solid rod-shaped structure. This design ensures the integrity of the lead screw 110, thereby guaranteeing the structural strength of the lead screw 110 and effectively preventing the optical shaft section 111 from breaking. In this embodiment, the positioning protrusion 1101 is located on the outer periphery of the optical shaft section 111. This design is because the threaded section 112 is used to drive the load lifting and lowering, while the surface of the optical shaft section 111 is flat. Therefore, placing the positioning protrusion 1101 on the outer periphery of the optical shaft section 111 can ensure the machining accuracy of the positioning protrusion 1101, reduce assembly errors, and thus reduce the machining difficulty of the lead screw 110, while also avoiding occupying the threaded section 112 and affecting the lifting stroke.

[0043] In this embodiment, the positioning protrusion 1101 is an annular positioning protrusion 1101. It should be noted that in this embodiment, the annular positioning protrusion 1101 means that the positioning protrusion 1101 is arranged around the outer periphery of the lead screw 110. The outer periphery of the positioning protrusion 1101 can be a cylindrical surface, a polygonal prism surface, a waist-shaped surface, or other non-cylindrical surfaces. At this time, the positioning grooves 1210 of the corresponding two half-sleeves 121 cooperate to form an annular positioning groove that matches the positioning protrusion 1101 after the two half-sleeves 121 are closed. The design of the annular positioning protrusion and the annular positioning groove can facilitate the half-sleeves 121 to be fitted onto the outside of the lead screw 110, so that the positioning groove 1210 can be quickly positioned and plugged into the positioning protrusion 1101. At the same time, the annular structure can also increase the mating area between the positioning groove 1210 and the positioning protrusion 1101, thereby improving the axial positioning effect of the spline sleeve 120.

[0044] To achieve synchronous rotation between the spline sleeve 120 and the lead screw 110, in this embodiment, the outer periphery of the optical shaft section 111 is provided with a non-cylindrical surface, and the inner wall of the spline sleeve 120 has a non-circular inner wall adapted to the non-cylindrical surface. Preferably, in this embodiment, the outer periphery of the positioning protrusion 1101 forms the aforementioned non-cylindrical surface. For example, the outer periphery of the positioning protrusion 1101 can be a prism surface, an elliptical cylinder surface, a D-shaped surface, etc. The bottom wall of the annular positioning groove formed by the two half-sleeves 121 after closing forms the aforementioned non-circular inner wall. Thus, the spline sleeve 120 and the optical shaft section can be synchronized through the cooperation of the non-cylindrical surface and the non-circular inner wall. The circumferential relative fixation of 111 allows the spline sleeve 120 and the lead screw 110 to rotate synchronously, resulting in a simple structure that eliminates the need for other connecting parts. Furthermore, compared to setting a non-cylindrical surface on the outer periphery of the optical axis section 111 outside the positioning protrusion 1101, this technical solution can effectively shorten the axial length of the optical axis section 111, thereby further reducing the machining difficulty of the lead screw 110. In addition, the axial and circumferential relative fixation of the spline sleeve 120 and the lead screw 110 can be achieved simultaneously through the cooperation of the positioning protrusion 1101 and the two positioning grooves 1210, achieving a dual-purpose effect.

[0045] To facilitate the machining and forming of the lead screw 110 and spline sleeve 120, in this embodiment, the outer peripheral surface of the positioning protrusion 1101 is a quadrangular prism surface, and the corresponding positioning groove 1210 is a V-shaped groove. The two groove walls of the V-shaped groove match the two adjacent surfaces of the quadrangular prism surface. In this case, the positioning grooves 1210 of the two half-sleeves 121 are completely identical.

[0046] Better, such as Figures 2 to 8As shown, the positioning protrusion 1101 extends from the end face of the optical axis section 111 toward the threaded section 112. A slot 1102 is provided between the positioning protrusion 1101 and the threaded section 112. The inner wall of the half-body 121 is provided with two inner shoulders 1211 that are axially spaced and surround the optical axis section 111. A positioning groove 1210 is formed between the two inner shoulders 1211. One inner shoulder 1211 abuts against the end face of the optical axis section 111, and the other inner shoulder 1211 is inserted into the slot 1102. Since the optical axis section of the lead screw that uses screws to fix the spline sleeve usually has the above-mentioned positioning protrusion 1101 and slot 1102, and the existing spline sleeve also has an inner shoulder 1211 that abuts against the end face of the optical axis section, this technical solution only needs to add an inner shoulder 1211 to the inside of the existing half-body 121 and insert it into the slot 1102. The modification of the lead screw 110 and spline sleeve 120 is small, thereby reducing the modification cost.

[0047] To achieve a connection where the spline sleeve 120 and the inner wall of the hollow shaft 130 are circumferentially fixed and axially movable, in this embodiment, the outer circumferential surface of the spline sleeve 120 is provided with a plurality of circumferentially spaced key teeth 122. The key teeth 122 extend along the axial direction of the lead screw 110. Each half-sleeve 121 has at least one key tooth 122 protruding from its outer circumferential side. The key teeth 122 on the two half-sleeves 121 are distributed in the same way, so that the two half-sleeves 121 are symmetrically arranged, thus eliminating the need to distinguish between the half-sleeves 121 during assembly. The inner circumferential surface of the hollow shaft 130 is provided with an axially penetrating keyway 131. The key teeth 122 are inserted into the keyway 131 and can slide relative to the keyway 131 along the axial direction of the lead screw 110. With this design, the key teeth 122 and keyway 131 can be inserted and fixed circumferentially relative to the hollow shaft 130, so that the hollow shaft 130 is subjected to balanced force. The key teeth 122 can slide relative to the keyway 131 along the axial direction of the lead screw 110, so that each half-body 121 can be connected to the hollow shaft 130 in an axial direction. The structure is relatively simple.

[0048] To prevent the positioning protrusion 1101 from dislodging from the positioning groove 1210 after the hollow shaft 130 is sleeved on the outside of the spline sleeve 120, the insertion depth of the positioning protrusion 1101 and the positioning groove 1210 in this embodiment is defined as H. When the heights of the two inner shoulders 1211 protruding from the inner wall of the half-sleeve 121 are the same, the radial dimension of the mating part of any one inner shoulder 1211 and the positioning protrusion 1101 is taken as H; when the heights of the two inner shoulders 1211 protruding from the inner wall of the half-sleeve 121 are different, the radial dimension of the mating part of the positioning protrusion 1101 and the inner shoulder 1211 with the smallest protrusion height is taken as H. Figure 8As shown, in this embodiment, the protrusion height of the inner shoulder 1211 that abuts against the end face of the optical axis segment 111 is greater than the protrusion height of the other inner shoulder 1211. Therefore, in this embodiment, the radial depth of the other inner shoulder 1211 inserted into the slot 1102 is taken as H. Figure 4 As shown, the gap between the outer periphery of the key tooth 122 and the bottom wall 1310 of the keyway is H1, satisfying H1 < H; and / or, the gap between the inner periphery of the hollow shaft 130 and the outer periphery of the spline sleeve 120 is H2, satisfying H2 < H. It should be noted that, in order to allow the hollow shaft 130 to slide smoothly relative to the spline sleeve 120, both H2 and H1 are greater than 0. This design can limit the radial outward movement range of the half-sleeve 121, thereby preventing the positioning protrusion 1101 from falling out of the positioning groove 1210, thus ensuring the reliability of the insertion and engagement between the positioning protrusion 1101 and the positioning groove 1210, so that the spline sleeve 120 can always be sleeved on the outside of the lead screw 110 and axially fixed relative to the lead screw 110.

[0049] Finally, as Figure 1 and Figure 7 As shown, the transmission assembly 100 in this embodiment also includes a first sleeve 140 fitted on the outside of the hollow shaft 130 and a second sleeve 150 fitted on the outside of the first sleeve 140. The hollow shaft 130 is provided with external threads. The top end of the first sleeve 140 is provided with a first transmission nut 160, which engages with the external threads of the hollow shaft 130. The top end of the second sleeve 150 is connected to a second transmission nut 170, which is threaded with the lead screw 110. The hollow shaft 130 and the second transmission nut 170 are rotated and fixed relative to each other in the axial direction through bearings. For a specific implementation method, please refer to CN 207016433U, which will not be described in detail here.

[0050] It is understood that in other embodiments of this utility model, if the outer peripheral surface of the positioning protrusion is a cylindrical surface, the bottom wall of the annular positioning groove formed by the two half-sleeves after being joined together is also a cylindrical surface. In this case, it is impossible to achieve circumferential fixation of the half-sleeves relative to the lead screw by the positioning protrusion and the annular positioning groove. Therefore, a non-cylindrical surface can be provided on the outer peripheral side of the optical axis section outside the positioning protrusion, and a non-circular inner wall adapted to the non-cylindrical surface can be formed on the inner wall of the spline sleeve. In this way, the spline sleeve can be circumferentially fixed relative to the lead screw.

[0051] It is understood that in other embodiments of this utility model, the outer periphery of the optical axis segment is provided with an annular positioning groove, and the inner wall of the half-sleeve is provided with a positioning protrusion extending radially inward. After the two half-sleeves are closed, the positioning protrusions on the two half-sleeves cooperate to form an annular positioning protrusion, and the annular positioning protrusion is inserted into the annular positioning groove. In order to achieve circumferential fixation of the spline sleeve relative to the lead screw, the bottom surface of the positioning groove can be formed as a non-cylindrical surface, and the inner surface of the annular positioning protrusion can be a non-cylindrical surface adapted to the bottom surface of the positioning groove; or, the portion of the outer periphery of the optical axis segment outside the positioning groove is provided with a non-cylindrical surface, and the inner wall of the spline sleeve has a non-circular inner wall adapted to the non-cylindrical surface.

[0052] Example 2

[0053] Compared to Embodiment 1, this embodiment differs in that the optical axis section in this embodiment is provided with multiple circumferentially spaced positioning protrusions. These positioning protrusions extend along the axial direction of the lead screw, and each of the corresponding two half-sleeves is provided with a positioning groove that radially engages with the positioning protrusion. This design allows for simultaneous axial and circumferential relative fixation of the spline sleeve and the lead screw through the engagement of the positioning protrusions and positioning grooves, achieving a dual-purpose effect.

[0054] It is understood that in other embodiments of this utility model, the optical axis section is provided with a plurality of circumferentially spaced positioning grooves, the positioning grooves extend along the axial direction of the lead screw, and the corresponding two half-sleeves are provided with positioning protrusions that radially engage with the positioning grooves.

[0055] Example 3

[0056] Combination Figure 9 As shown, this embodiment also discloses a linear lifting device, including a sleeve assembly 200, a transmission assembly 100, a bottom shell 300, and a drive device (not shown in the figure) placed inside the bottom shell 300. The transmission assembly adopts the transmission assembly described in Embodiment 1 or 2. The sleeve assembly 200 includes an inner tube 210, a middle tube 220, and an outer tube 230. The second sleeve 150 is connected to the middle tube 220 through a fixing seat 400. The top of the inner tube 210 is fixedly connected to the bottom shell 300, and the bottom of the outer tube 230 is fixedly connected to the bottom of the first sleeve 140 through a base plate 500. The drive device includes a motor and a reduction gearbox. The reduction gearbox includes a reduction gearbox housing and a worm gear disposed in the reduction gearbox housing. The lead screw 110 extends into the reduction gearbox housing and engages with the worm gear for transmission. The motor drives the worm gear to drive the lead screw 110 to rotate synchronously to realize the extension and retraction of the sleeve assembly 200.

[0057] In addition to the preferred embodiments described above, there are other embodiments of this utility model. Those skilled in the art can make various changes and modifications based on this utility model. As long as they do not depart from the spirit of this utility model, they should all fall within the scope defined in the claims of this utility model.

Claims

1. A transmission assembly for a linear lifting device, comprising a lead screw, a splined sleeve, and a hollow shaft sleeved on the outside of the lead screw, wherein the splined sleeve is sleeved on the outside of the lead screw and rotates synchronously with the lead screw, and the splined sleeve and the inner wall of the hollow shaft maintain a circumferentially fixed and axially movable connection, so that the lead screw and the hollow shaft can extend and retract relative to each other axially, characterized in that, The spline sleeve is composed of two half-sleeves. The two half-sleeves are joined together radially along the lead screw to form a spline sleeve. One of the inner walls of the half-sleeves and the outer periphery of the lead screw is provided with a positioning protrusion, and the other is provided with a positioning groove. The positioning protrusion and the positioning groove are radially inserted to fix the half-sleeves axially relative to the lead screw. The hollow shaft is sleeved on the outside of the spline sleeve and is used to prevent the positioning protrusion from falling out of the positioning groove.

2. The drive assembly of the linear lift device of claim 1, wherein, The lead screw includes a threaded section and a smooth shaft section connected along its axial direction, and the outer peripheral side of the smooth shaft section is provided with the positioning protrusion or positioning groove.

3. The drive assembly of the linear lift device of claim 2, wherein, The optical axis segment is provided with an annular positioning protrusion or an annular positioning groove, and the outer periphery of the optical axis segment is provided with a non-cylindrical surface. The inner wall of the spline sleeve has a non-circular inner wall that is adapted to the non-cylindrical surface.

4. The drive assembly of the linear lift device of claim 3, wherein, The outer peripheral surface of the positioning protrusion forms the non-cylindrical surface, or the bottom surface of the positioning groove forms the non-cylindrical surface.

5. The drive assembly of the linear lift of claim 2, wherein, The optical axis segment is provided with multiple circumferentially spaced positioning protrusions or positioning grooves.

6. The drive assembly of the linear lift of claim 2, wherein, The optical axis segment is provided with a positioning protrusion, which extends from the end face of the optical axis segment toward the threaded segment. A slot is provided between the positioning protrusion and the threaded segment. The inner wall of the half-body is provided with two inner shoulders that are axially spaced apart, and the positioning groove is formed between the two inner shoulders. One inner shoulder abuts against the end face of the optical axis segment, and the other inner shoulder is inserted into the slot.

7. The drive assembly of the linear lift of claim 2, wherein, The optical axis segment is a solid rod-shaped structure.

8. The drive assembly of the linear lift of claim 1, wherein, The outer circumferential surface of the spline sleeve is provided with a plurality of circumferentially spaced key teeth, and the outer circumferential surface of each half-sleeve is provided with at least one of the key teeth. The inner circumferential surface of the hollow shaft is provided with a keyway, and the key teeth are inserted into the keyway and can slide relative to the keyway along the axial direction of the lead screw.

9. The drive assembly of the linear lift device of claim 8, wherein, The insertion depth of the positioning protrusion and the positioning groove is H, the gap between the key teeth and the bottom wall of the keyway is H1, satisfying H1 < H; and / or, the gap between the inner circumferential surface of the hollow shaft and the outer circumferential surface of the spline sleeve is H2, satisfying H2 < H.

10. Linear lifting device comprising a sleeve assembly, a transmission assembly and a drive device, said drive device driving the sleeve assembly to extend and retract through said transmission assembly, characterized in that, The transmission assembly adopts the transmission assembly according to any one of claims 1 to 9, and the driving device includes a motor, which is coupled with the lead screw.

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