Curve conjugation based symmetrical cambered surface conjugate curve gears and engagement pair thereof

The invention discloses a point contact gear and a meshing pair based on conjugate curves and a machining tool of the point contact gear and the meshing pair. The point contact gear comprises a convex gear and a concave gear which are in one-point or multi-point contact meshing, and a contact curve composed of meshing points on a tooth profile curved surface of the convex gear and a contact curve composed of meshing points on the concave gear are the conjugate curves. According to the point contact gear meshing pair based on the conjugate curves, a convex gear tooth surface and a concave gear tooth surface are in one-point or multi-point contact at the same time according to the meshing mode of the meshing pair, and the contact tracks of the contact points on the tooth surfaces are smooth space curves. The meshing characters of the conjugate curves are inherited by the transmission, point contact tooth profiles are high in contact strength, high in bearing capacity, high in transmission efficiency and low in lubricating oil temperature rise, the sliding ratio is greatly lowered, and abrasion is low. Meanwhile, gear meshing achieves one-point contact or double-point contact or multi-point contact at the same time through different contact curves according to different use needs, and the problem that an existing point contact gear with a ball race pipe type envelope surface with a sphere center moving along a circle center curve as a tooth profile curved surface only achieves one-point contact in the meshing process is solved.

Point contact gear and meshing pair based on conjugate curves and machining tool thereof

The invention relates to a spiral-arc gear mechanism for parallel-shaft external-engaged transmission. The spiral-arc gear mechanism comprises a transmission pair consisting of a bull wheel and a pinion wheel, wherein the pinion wheel is connected with an input shaft, the bull wheel is connected with an output shaft, the axis of the pinion wheel and the axis of the bull wheel are parallel to each other, spiral arc grooves are uniformly distributed in the external surface of a cylindrical body of the pinion wheel, spiral arc teeth are uniformly distributed in the external surface of a cylindrical body of the bull wheel, both center lines of the spiral arc grooves and center lines of the spiral arc teeth are cylindrical helices, and the spiral arc grooves of the pinion wheel are matched with the spiral arc teeth of the bull wheel. When the pinion wheel and the bull wheel are mounted, one pair of spiral arc groove and spiral arc tooth is firstly enabled to be engaged with each other, a driver drives the input shaft and the pinion wheel to rotate, and thus, the external-engaged transmission between the two parallel shafts is realized; the shapes of the spiral arc grooves and the shapes of the spiral arc teeth can be determined by parameters, such as a transmission ratio, and a central line equation. The spiral-arc gear mechanism is simple and compact in structure, small in size, light in weight, high in strength and rigidity, high in contact ratio and high in single-stage transmission ratio and is suitable for being applied to the fields of small, micro and conventional machinery.

Spiral-arc gear mechanism for parallel-shaft external-engaged transmission

The invention discloses a Tu's involute arc gear tooth, which comprises tooth top arcs, tooth flute bottoms, and involutes, wherein each tooth is provided with two involutes for transitional correction and arranged on two sides, and the tooth width is equal to the tooth height. The arc tooth belongs to a new design concept, the tooth width is equal to the tooth height, the two arcs of each tooth have same diameter, the two involutes on two sides of each tooth are used for transitional correction, a running path of tooth forms is reasonable without root rubbing, approximate rolling friction between circles is generated during transmission operation and different from sliding friction generated in contact of micro-arc profiles of common involute gears, friction coefficient is extremely small so that transmission loss is reduced, and energy conservation and transmission efficiency improvement are achieved. No stress point is arranged on each arc, so that the Tu's involute arc gear tooth is higher in strength and capable of transmitting higher torque. The friction coefficient can be reduced by more than 50% according to different structures and loads, the energy saving effect is evident, and especially the effect of the Tu's involute arc gear tooth is better in use of an arc bevel gear with spiral friction angle necessarily reduced for achieving the effect of the approximate rolling friction during axial intersecting transmission.

Tu's involute arc gear tooth

The invention discloses a harmonic reducer of an improved structure. The harmonic reducer comprises a flexible gear, a rigid gear, a cross cylindrical roller bearing, a cam and a flexible bearing. The flexible gear is provided with an external gear part and a transmission part, flexible gear teeth are arranged on the outer circumferential surface of the external gear part, a flexible gear arc tooth root is arranged at the position, between the roots of every two adjacent flexible gear teeth, of the external gear part, the tooth surface of each flexible gear tooth is an involute tooth surface, and a flexible gear transition arc surface is arranged between the tooth top and the involute tooth surface of each flexible gear tooth. Rigid gear teeth are arranged on the circumferential surface of a rigid gear center hole in the core of the rigid gear, a rigid gear arc tooth root is arranged at the position, between the roots of every two adjacent rigid gear teeth, of the rigid gear, the tooth surface of each rigid gear tooth is an involute tooth surface, and a rigid gear transition arc surface is arranged between the tooth top and the involute tooth surface of each flexible gear tooth. Through the structural design, the harmonic reducer has the advantage of being reasonable in design; the efficiency of meshing between the rigid gear and the flexible gear can be effectively improved, friction generated in meshing between the rigid gear and the flexible gear can be reduced, and the service life can be effectively prolonged.

Harmonic reducer of improved structure

The invention discloses an involute arc tooth profile bevel gear and a meshing pair thereof. The tooth profile curve of bevel gear is formed by the way that an arc does helical motion along the tooth surface contact line on involute helicoids, thus having the advantages that involute gear center distance has separability and is convenient to measure, involute gear is convenient to manufacture andan arc gear has high contact strength and good running-in property, tooth surface contact stress is reduced, tooth surface carrying capacity is greatly improved, and processing is convenient; and thetooth curve of the arc and the radial length of involute participating in meshing are short, thus avoiding undercutting phenomenon of standard gear, so that minimum tooth number of the gear can reach1. Compared with the gear in the prior art, weight and size are greatly reduced; and the meshing pair adopts the way that a convex gear is meshed with a concave gear, and carrying capacity is high.

Involute arc tooth profile bevel gear and meshing pair thereof

The invention discloses a bevel gear with combined arc tooth profile curves and involute tooth profile curves, wherein the tooth profile curves of the bevel gear comprise a top convex-arc segment, an involute segment and a root concave-arc segment, wherein the top convex-arc segment, the involute segment and the root concave-arc segment are sequentially connected from the top to the root; the top convex-arc segment and the root concave-arc segment are both tangential to the involute segment; and the radius of the root concave-arc segment is larger than that of the top convex-arc segment. The bevel gear of the invention has the advantages of separability of center distance of the involute gear; the bevel gear is simple in manufacturing, convenient in measuring, large in contact strength of the arc gear, excellent in running-in performance and the like; the contact stress of the gear surface can be largely reduced and the loading ability of the gear surface can be largely improved. In addition, the bevel gear does not have undercutting phenomenon, and the minimum number of teeth can be one, so that the bevel gear has remarkable meaning for realizing light weight of the gear and the transmission device thereof.

Bevel gear with combined arc tooth profile curves and involute tooth profile curves

Disclosed is a bevel gear with an involute cambered surface tooth profile. A tooth profile curved surface of the bevel gear is formed through spiral movement of an arc line along a tooth surface contact line on an involute spiral surface, thereby achieving advantages of being flexible in center distance and convenient for manufacturing and measuring as an involute gear and having strong contact strength and excellent running performance as a circular arc gear, reducing tooth surface contact stress, dramatically increasing bearing capacity of the gear, and making manufacturing convenient. An arc-shaped tooth curve and the involute participating in the meshing are very short in the radial direction, so as to avoid undercutting of a standard gear, and enable the smallest number of the teeth of gear to reach 1, significantly reducing the weight and size. Also disclosed is a meshing pair formed by the bevel gears. The meshing pair adopts a meshing manner of a convex gear and a concave gear, achieving excellent bearing performance.

Bevel gear with involute cambered surface tooth profile and meshing pair thereof

Disclosed are a point contact gear based on conjugate curves, a meshing pair and a machining tool therefor. The point contact gear comprises a convex gear and a concave gear which mesh with each other in one-point or multi-point contact, and a contact curve composed of meshing points on a tooth profile curved surface of the convex gear and a contact curve composed of the meshing points on the concave gear are the conjugate curves. Further disclosed is a point contact gear meshing pair based on conjugate curves, a meshing method of the meshing pair is making both a convex gear tooth surface and a concave gear tooth surface in one-point or multi-point contact, and a contact track of the contact points on each of the tooth surfaces is a smooth space curve. The meshing characters of the conjugate curves are inherited; in addition, point contact tooth profiles are high in contact strength, high in bearing capacity, high in transmission efficiency and low in lubricating oil temperature rise, the sliding ratio is greatly lowered, and abrasion is low.

Chaoyang Li

Papers

Point contact gear and meshing pair based on conjugate curves and machining tool thereof

Involute arc tooth profile bevel gear and meshing pair thereof

Bevel gear with combined arc tooth profile curves and involute tooth profile curves

Bevel gear with involute cambered surface tooth profile and meshing pair thereof

Point contact gear based on conjugate curves, meshing pair and machining tool therefor