The present invention relates to a concave-convex arc line gear mechanism for parallel shaft transmission, which comprises a driving line gear and a driven line gear, axes of the driving line gear and the driven line gear being parallel to each other to form a transmission pair. The driving line gear is consisted of convex teeth and a driving wheel body, a surface of the convex tooth comprising a pair of convex arc-shaped tooth flanks and a tooth top surface The driven line gear is consisted of concave teeth and a driven wheel body, a surface of the concave tooth comprising a pair of concave arc-shaped tooth flanks and a tooth bottom surface A meshing track of the transmission pair during transmission is a space curve. One arc-shaped tooth flank of the driving line gear and one arc-shaped tooth flank of the driven line gear present a point contact of convex arc and concave arc at a meshing point. Tooth shapes of the driving line gear and the driven line gear are interchangeable, i.e., the driving line gear has concave teeth, while the driven line gear has convex teeth. The line gear mechanism of the present invention has high transmission ratio, high contact strength, high load-bearing capacity, wide range of application, and is easy to be machined, which is especially suitable for space-limited microminiature mechanical, micro mechanical and conventional mechanical applications.

A gear mechanism (6) for a rolling mill drive includes at least one involute cylindrical gear tooth system between at least two intermeshing gear wheels (3) with asymmetrical gearing. The normal pressure angle of the load-bearing tooth flanks (5) of the gear wheels (3) is greater than 20 and less than or equal to 30, and the normal pressure angle of the trailing flanks (4) of the gear wheels is greater than or equal to 14 and less than 22. A rolling mill drive has a gear mechanism (6) of this type, and the gear mechanism (6) is used as a rolling mill gear mechanism.

A gear assembly that can prevent a reduction in power transmission efficiency and a manufacturing method thereof are provided. The gear assembly comprises a first gear and a second gear. The gear assembly is designed in such a manner that first gear tooth and the second gear tooth are contacted properly to each other in a plane of action when operated in a predetermined condition. A rigidity reducing portion is formed on a first base portion to avoid improper contact in the plane of action when the gear assembly is operated in a different condition.

A drive transmission mechanism includes a first gearbox including a driving source, a first gear train, a first frame configured to support one ends of a plurality of shafts of the first gear train, and a first gear cover configured to support the other ends of the shafts of the first gear train, wherein the first gear box is configured to transmit a driving force from the driving source; and a second gearbox including a second gear train, a second frame configured to support one ends of a plurality of shafts of the second gear train, and a second gear cover configured to support the other ends of the shafts of the second gear train, wherein the second gearbox is configured to receive the driving force from the driving source through the first gear train and configured to transmit the driving force. The second gearbox is fixed to the first gearbox.

Provided is a herringbone planetary gear transmission device with a constant meshing characteristics constructed tooth pair, which relates to the technical field of gear transmission. The transmission device includes a sun gear with a constructed tooth pair, a planetary gear with a constructed tooth pair and an internal gear with a constructed tooth pair based on conjugate curves. Normal tooth profiles of the gears with a constructed tooth pair in the present disclosure are all the same combined curve and can be machined by using the same cutter. A common normal at an inflection point or a tangent point of the curve passes through a pitch point of a meshing gear pair, and a sliding ratio of the meshing gear pair is adjusted according to an adjusted position of the inflection point or the tangent point. A contact ratio of the meshing gear pair is designed as an integer.

Provided is an internal meshing cylindrical gear pair with a constant meshing characteristics constructed tooth pair. The internal meshing cylindrical gear pair with a constructed tooth pair includes an external cylindrical gear with a constructed tooth pair and an internal cylindrical gear with a constructed tooth pair based on conjugate curves. In the present disclosure, normal tooth profile curves of the external cylindrical gear with a constructed tooth pair and the internal cylindrical gear with a constructed tooth pair are continuous combined curves with the same curve shape, which facilitates machining by the same cutter. A common normal at an inflection point or a tangent point of the continuous combined curve passes through a pitch point of the gear pair, and a position of the inflection point or the tangent point can be adjusted as required, so as to adjust a sliding ratio of the gear pair.

Provided is a herringbone gear pair with a constant meshing characteristics constructed tooth pair. The herringbone gear pair with a constructed tooth pair includes a herringbone gear I with a constructed tooth pair and a herringbone gear II with a constructed tooth pair based on conjugate curves. In the present disclosure, normal tooth profile curves of the herringbone gear pair with a constructed tooth pair are continuous combined curves with the same curve shape, which facilitates machining by the same cutter. A common normal at an inflection point or a tangent point of the continuous combined curve passes through a pitch point of the gear pair, and a position of the inflection point or the tangent point can be adjusted according to an actual demand. A contact ratio of the herringbone gear pair with a constructed tooth pair is designed as an integer.

Each of gear teeth of an external gear has a tooth-bottom portion, a tooth-middle portion and a tooth-front portion. The tooth-middle portion is operatively engaged with an internal gear. A cross-sectional shape of the tooth-bottom portion is formed by a hypocycloid curved line. A cross-sectional shape of the tooth-middle portion is formed by an epicycloid curved line. A cross-sectional shape of the tooth-front portion is formed by a first predetermined curved line, which is located at a position closer to a first pitch circle of the external gear in a radial-inward direction from a reference epicycloid curved line. The reference epicycloid curved line is continuously connected to each of the curved lines of the tooth-middle portion at both circumferential sides of each gear tooth. As a result, the tooth-front portion is so formed that a part of the tooth-front portion is escaped in the radial-inward direction from the reference epicycloid curved line.

A resin gear 12 includes tooth surfaces 13a and 13b formed front and rear with respect to a rotating direction and an addendum 13c formed between these tooth surfaces and also includes a plurality of helical teeth 13 provided with inclination at a predetermined twist angle with respect to an axial direction.

On a part of a contact portion on the tooth surface with a tooth surface of the other gear, a relief portion 15 so as not to touch the tooth surface of the other gear is formed.

Damage on the tooth surface caused by stress concentration can be prevented as much as possible.

Gear mechanism, in particular coaxial gear mechanism or linear gear mechanism, having a toothing system, a tooth carrier with radially oriented guides, teeth which are received in the guides for engagement with the toothing system, the teeth being mounted in the guides such that they can be displaced radially relative to the tooth carrier in the direction of their longitudinal axis, a cam disk for radially driving the teeth, the tooth carrier comprising a first tooth carrier part and a second tooth carrier part.