Stroke limiting device of tubular motor

Abstract

The utility model discloses a stroke limiting device of a tubular motor, which comprises a lead screw assembly and a worm used for adjusting the stroke, the lead screw assembly comprises a lead screw and a nut, the lead screw comprises a threaded part, and the nut is sleeved on the periphery of the threaded part and is in threaded connection with the threaded part; the lead screw further comprises a straight tooth part coaxial with the threaded part, and the worm is meshed with the straight tooth part. Compared with the prior art, the self-locking device has the advantages that the straight teeth of the worm and the straight teeth of the lead screw are meshed, the worm is provided with the helical teeth, and the straight teeth are matched with the helical teeth, so that the self-locking function (reverse locking) can be realized, the deviation of a stroke limiting point caused by the rotation of the lead screw due to the vibration of the motor is prevented, and the reliability of the device is improved.

Description

Technical Field

[0001] This utility model relates to power devices, and more particularly to a travel limit device for a tubular motor. Background Technology

[0002] Existing projection screens, motorized curtains, and roller shutters typically use motors for raising and lowering. To limit the travel of these devices, a travel limit structure is usually included. This travel limit structure contains an adjustment mechanism; by operating this mechanism, the travel of the projection screen or curtain can be independently adjusted according to the actual required height, without interference, greatly facilitating the user.

[0003] Existing stroke limiting structures, such as the stroke mechanism of a tubular motor disclosed in Chinese Patent Application No. 201520522731.2, include a base plate, an inner end cover, and an outer end cover fixed together by screws. A sprocket is provided in the cavity formed between the inner end cover and the outer end cover. A worm gear cover plate is provided between the sprocket and the inner end cover. Two symmetrically arranged axial worm gears are provided between the worm gear cover plate and the inner end cover. The worm gears mesh with the worm through gears. Side screws are provided on both sides of the transmission screw and connected to it. The bottom end of the side screws is fixedly connected to the worm gears.

[0004] This type of stroke limiting structure, where the lead screw is composed of a threaded part and a helical gear assembled into a complete lead screw, meshes with an adjusting worm gear for stroke adjustment and setting. The following problems exist: 1) The threaded part and the helical gear part are two separate components, which may lead to assembly and adjustment errors; 2) The helical gear makes the injection molding process more complex and difficult than that of a spur gear.

[0005] Therefore, improvements are still needed. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a travel limiting device for a tubular motor that addresses the shortcomings of the existing technology and improves reliability.

[0007] The technical solution adopted by this utility model to solve the above-mentioned technical problem is as follows: a travel limiting device for a tubular motor, comprising a lead screw assembly and a worm gear for adjusting the travel, wherein the lead screw assembly comprises a lead screw and a nut, the lead screw includes a threaded portion, and the nut is sleeved on the outer circumference of the threaded portion and threadedly connected to the threaded portion; characterized in that:

[0008] The lead screw also includes a straight tooth portion coaxially arranged with the threaded portion, and the worm gear meshes with the straight tooth portion.

[0009] By engaging the spur teeth of the worm and the lead screw, and since the worm is helical, the combination of spur teeth and helical teeth can achieve a self-locking function (reverse jamming), preventing the lead screw from rotating due to motor vibration and causing the stroke limit point to shift, thereby improving the reliability of the device.

[0010] Preferably, the threaded portion and the spur gear portion are integrally injection molded structures. Moreover, the injection molding process for spur gears is simple, and the traditional copper screw is replaced by injection molding, making the screw and spur gear into a single part. This reduces the number of parts, standardizes the materials, and effectively lowers costs.

[0011] To facilitate the rotation of the lead screw, the stroke limiting device also includes an intermediate transmission gear for inputting power. The lead screw assembly has two arranged in parallel, and the intermediate transmission gear is located between the two lead screw assemblies and meshes with each nut.

[0012] To facilitate power on / off control of the motor when the travel limit position is reached, the travel limit device also includes a stop block and a limit switch. The stop block is located at the end of the lead screw away from the straight tooth section and can cooperate with the nut. The limit switch is located adjacent to the stop block and can be triggered by the stop block.

[0013] Preferably, the lead screw assembly, intermediate transmission gear, stop block, and limit switch are mounted on the bracket.

[0014] Preferably, to facilitate operation of the worm, the end of the worm is formed with an inner hole for inserting an adjustment tool.

[0015] Compared with the prior art, the advantages of this utility model are as follows: by making the spur teeth of the worm and the lead screw mesh, since the worm is helical, the spur teeth and helical teeth can achieve a self-locking function (reverse jamming), preventing the lead screw from rotating due to motor vibration and causing the stroke limit point to shift, thereby improving the reliability of the device; by making the threaded part and the spur teeth part into an integral injection molding structure, the injection molding process is simple, and the traditional copper screw is changed to injection molding, making the screw and spur teeth into a single part, reducing the number of parts, unifying the materials, and effectively reducing costs. Attached Figure Description

[0016] Figure 1 A schematic diagram of the tubular motor used in the stroke limiting device of this utility model embodiment;

[0017] Figure 2 for Figure 1 A schematic diagram of a tubular motor with its outer tube concealed.

[0018] Figure 3 This is a schematic diagram of the travel limiting device according to an embodiment of the present utility model;

[0019] Figure 4 This is a schematic diagram of the hidden part of the travel limit device in an embodiment of the present utility model. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions.

[0021] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Since the embodiments disclosed in this utility model can be arranged in different directions, these terms indicating direction are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0022] See Figures 1-4 A travel limiting device for a tubular motor, wherein the tubular motor used includes an outer tube 200, a travel head 300 disposed at the end of the outer tube 200, and a travel limiting device 100 disposed inside the outer tube 200 and connected to the travel head 300.

[0023] The travel limit device 100 includes a lead screw assembly 1, an intermediate transmission gear 2, a stop block 3, and a travel switch 4. The lead screw assembly 1 includes a lead screw and a nut 13. The lead screw includes a threaded portion 11 and a spur gear portion 12, which are coaxially arranged and preferably have an integral injection-molded structure. The nut 13 is sleeved on the outer circumference of the threaded portion 11 and the two are threadedly connected, so that when the lead screw rotates about its own axis, the nut 13 can move linearly along the axial direction of the lead screw.

[0024] The travel limit device 100 also includes a worm gear 5 and a bracket 6. The aforementioned lead screw assembly 1, intermediate transmission gear 2, stop block 3, and limit switch 4 are mounted on the bracket 6. The stop block 3 is positioned adjacent to the end of the threaded portion 11 of the lead screw, which is the end away from the straight tooth portion 12. When the nut 13 moves to this position, it can push the stop block 3. The limit switch 4 is positioned adjacent to the stop block 3, on the side of the stop block 3 away from the nut 13. When the stop block 3 is pushed towards the limit switch 4 by the nut 13, it can activate the contacts of the limit switch 4, thereby triggering the limit switch 4.

[0025] The lead screw assembly 1 has two arranged in parallel, with the intermediate transmission gear 2 located between the two lead screw assemblies 1 and meshing with the nut 13.

[0026] In operation, the transmission tube of the tubular motor drives the internal gear sleeve to rotate, thereby transmitting power to the intermediate transmission gear 2 that meshes with the internal gear sleeve. This causes the intermediate transmission gear 2 to rotate, which in turn drives the nut 13, which meshes with it, to move linearly left and right along the threaded portion 11 of their respective lead screws. When the nut 13 hits the stop block 3, the handle on the stop block 3 presses against the contact on the limit switch 4, thus cutting off the power to the tubular motor and stopping its rotation. The above working principle is the same as in existing technology.

[0027] The worm 5 meshes with the spur gear 12 for adjusting the stroke limit. It can extend into the stroke head 300. Each end of the worm 5 extending into the stroke head 300 has an inner hole 51. The inner hole 51 communicates with the outside of the stroke head 300 from the axial outside or radial outside, so that the adjusting tool can be inserted into the inner hole 51, rotate the worm 5 to rotate the lead screw, change the initial position of the nut 13, and thus adjust the stroke. This setting allows for convenient operation even in special installation environments.

[0028] Since the worm 5 is helical, while the lead screw that it works with is spur, the combination of spur and helical teeth can achieve a self-locking function (reverse locking), preventing the lead screw from rotating due to motor vibration and causing the travel limit point to shift.

Claims

1. A travel limiting device for a tubular motor, comprising a lead screw assembly (1) and a worm gear (5) for adjusting the travel, wherein the lead screw assembly (1) comprises a lead screw and a nut (13), the lead screw comprising a threaded portion (11), and the nut (13) being sleeved on the outer periphery of the threaded portion (11) and threadedly connected to the threaded portion (11); characterized in that: The lead screw also includes a straight tooth portion (12) coaxially arranged with the threaded portion (11), and the worm (5) meshes with the straight tooth portion (12).

2. The travel limiting device for a tubular motor according to claim 1, characterized in that: The threaded portion (11) and the straight tooth portion (12) are integral injection molded structures.

3. The travel limiting device for a tubular motor according to claim 1 or 2, characterized in that: The travel limiting device also includes an intermediate transmission gear (2) for inputting power. The lead screw assembly (1) has two arranged side by side. The intermediate transmission gear (2) is located between the two lead screw assemblies (1) and meshes with each nut (13).

4. The travel limiting device for a tubular motor according to claim 3, characterized in that: The travel limit device also includes a stop block (3) and a travel switch (4). The stop block (3) is located at the end of the lead screw away from the straight tooth portion (12) and can cooperate with the nut (13). The travel switch (4) is located adjacent to the stop block (3) and can be triggered by the stop block (3).

5. The travel limiting device for a tubular motor according to claim 4, characterized in that: The lead screw assembly (1), intermediate transmission gear (2), impact block (3) and limit switch (4) are mounted on the bracket (6).

6. The travel limiting device for a tubular motor according to claim 1 or 2, characterized in that: The end of the worm (5) has an inner hole (51) for inserting an adjustment tool.

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