Worm gear linear drive structure and worm gear linear drive module

Abstract

A worm gear linear drive structure includes an internal helical gear member, a rod, a plurality of worm gear sets, and a preload assembly. The internal helical gear member has an axially extending inner hole, and its inner circumferential surface is provided with a helical tooth structure. The rod passes through the inner hole and extends axially. The plurality of worm gear sets are disposed within the inner hole and positioned between the internal helical gear member and the rod. Each worm gear set includes at least one worm wheel, which has a tooth structure on its outer circumferential surface. The tooth lines of the worm wheel structure interlock with the tooth lines of the helical gear structure, and the worm wheel forms frictional contact with the outer circumferential surface of the rod. The preload assembly is disposed radially outside the worm gear sets to apply preload to the worm gear sets, thereby creating static friction between the worm wheels and the rod. Thus, when the internal helical gear member is driven to rotate, it can drive the worm wheels to rotate, and further push the rod to move axially through the worm wheels. On the other hand, when the rod is subjected to an external force that exceeds the static friction, the rod will slip relative to the worm gear assembly to block the transmission of excessive reaction force and prevent structural damage.

Claims

1. A worm gear linear drive structure, comprising: an internal helical gear member having an inner hole extending axially therein, the inner circumferential surface of the inner hole being provided with a helical tooth structure; a rod passing through the inner hole and extending axially therein; a plurality of worm gear sets disposed within the inner hole and disposed between the internal helical gear member and the rod, each worm gear set comprising at least one worm wheel, the worm wheel being provided with a tooth structure on its outer circumferential surface, the tooth line of the tooth structure intersecting and meshing with the tooth line of the helical tooth structure, and the outer circumferential surface of each worm wheel in frictional contact with the outer circumferential surface of the rod; and a preload assembly disposed radially outside the plurality of worm gear sets for applying preload to each worm gear set.

2. The worm gear linear drive structure as described in claim 1 further comprises: a main bearing disposed on the inner circumferential surface of at least one end of the internal helical gear member; a fixing frame disposed on an axially outer side of the main bearing, the fixing frame having a through inner hole; and a sliding bushing assembled in the inner hole of the fixing frame, the sliding bushing having a through hole; wherein, The rod also passes through the inner hole of the main bearing, the fixed bracket, and the through hole of the sliding bushing.

3. The worm gear linear drive structure as described in claim 1, wherein, At least a portion of the outer peripheral surface of the rod has a smooth surface for frictional contact with each of the worm gears.

4. The worm gear linear drive structure as described in claim 1, wherein, The member has a circular, elliptical, or polygonal geometric cross-section.

5. The worm gear linear drive structure as described in claim 1, wherein, Each worm gear assembly further includes: a retainer having a body and two pairs of ends extending from both sides of the body, each end having a through hole, and a space between the pairs of ends, with each worm gear disposed in the space; at least one worm gear shaft passing through the through holes of the retainer and penetrating the corresponding worm gear; and at least two worm gear bearings respectively disposed in the inner holes of the worm gears and sleeved on the worm gear shafts.

6. The worm gear linear drive structure as described in claim 1, wherein, Each worm gear has a concave profile on its outer peripheral surface, the shape of which corresponds to the outer peripheral profile of the rod.

7. The worm gear linear drive structure as described in claim 1, wherein, The preload assembly includes a plurality of torque plates, each of which has a hook.

8. The worm gear linear drive structure as described in claim 7, wherein, The plurality of torsion plates are stacked to form a torsion plate group, and each torsion plate group is disposed on two adjacent retainers and is engaged with the radial outer side of the two retainers through the hooks to apply preload to the two retainers.

9. A worm gear linear drive module, comprising: a worm gear linear drive structure as described in claim 2; a housing defining an accommodating space, wherein the worm gear linear drive structure is disposed in the accommodating space; a stator fixedly disposed within the housing and surrounding the outer side of the inner helical gear member for driving the inner helical gear member to rotate; and a flange cover fixedly disposed at one end of the housing.

10. A worm gear linear drive module, comprising: a worm gear linear drive structure as described in claim 2; a housing defining an accommodating space, wherein the worm gear linear drive structure is disposed in the accommodating space; a stator fixedly disposed within the housing; a rotor disposed in the space surrounded by the stator and rotatable relative to the stator; a rotor structure having one end connected to the rotor and the other end connected to the internal helical gear member; and an end cap fixedly disposed at one end of the housing.

Images