阅读说明：本技术 一种多级同轴面接触活齿精密减速器 (Multistage coaxial surface contact oscillating tooth precision speed reducer ) 是由 杨玉虎 胡自昂 张帆 周国成 于 2019-09-23 设计创作，主要内容包括：本发明公开了一种多级同轴面接触活齿精密减速器,主要包括中心齿轮,三个周向均布的行星齿轮,曲柄轴,偏心盘,激波器,壳体,活齿,面齿圈,输出盘。壳体固定,高速转动由与壳体同轴的中心齿轮输入,中心齿轮与三个行星齿轮啮合,每个行星齿轮和一个曲柄轴固联,三个同向偏置的曲柄轴与偏心盘组成转动副,偏心盘放置在激波器上,推动激波器自转,驱动活齿做轴向移动,活齿与面齿圈啮合,使面齿圈产生低速转动,面齿圈和输出盘固联,输出盘输出低速转动。本发明减速器具有大速比、匀速输出等优点,并且与一般减速器相比,承载能力大,结构紧凑,能够满足大速比高承载低回差场合下减速器的需求。(The invention discloses a multistage coaxial surface contact oscillating tooth precision reducer which mainly comprises a central gear, three planetary gears which are uniformly distributed in the circumferential direction, a crank shaft, an eccentric disc, a shock absorber, a shell, an oscillating tooth, a surface gear ring and an output disc. The shell is fixed, the high-speed rotation is input by a central gear which is coaxial with the shell, the central gear is meshed with three planetary gears, each planetary gear is fixedly connected with a crank shaft, three crank shafts which are offset in the same direction and an eccentric disc form a revolute pair, the eccentric disc is placed on a shock wave device to push the shock wave device to rotate, the movable teeth are driven to move axially and meshed with the face gear ring, the face gear ring rotates at a low speed, the face gear ring is fixedly connected with the output disc, and the output disc outputs the low-speed rotation. The speed reducer has the advantages of large speed ratio, uniform output and the like, and compared with the common speed reducer, the speed reducer has large bearing capacity and compact structure, and can meet the requirements of the speed reducer on occasions with large speed ratio, high bearing capacity and low return difference.)

1. A multistage coaxial surface contact oscillating tooth precision speed reducer comprises a high-speed input component, a low-speed output component and a shell (1), wherein the high-speed input component comprises an input shaft (8), a central gear (9) fixedly connected with the input shaft (8), three planetary gears (7) uniformly distributed in the circumferential direction and crank shafts (5) fixedly connected with the three planetary gears (7) respectively, and an eccentric disc (12) and an exciter (3) are sleeved on the three crank shafts (5); the low-speed output component consists of a movable tooth (17), a face gear ring (20) and an output disc (14); the input shaft (8), the central gear (9), the shock wave device (3), the shell (1), the face gear ring (20) and the output disc (14) are coaxially arranged;

the method is characterized in that:

the high-speed input component is a planetary gear train, and the low-speed output component is a movable tooth speed reducer; the high-speed input component and the low-speed output component form a K-H-V type epicyclic gear train together;

the input shaft (8) bears high-speed input motion, three planetary gears (7) which are uniformly distributed in the circumferential direction are meshed with a central gear (9) at the same time, the crank directions of three crankshafts (5) are consistent and are positioned in three stepped holes which are uniformly distributed in the circumferential direction on an eccentric disc (12), and the eccentric disc (12) is placed on the shock wave device (3);

be equipped with N guide way (21) on casing (1), the lower extreme of shock wave ware (3) has the face cam that circumference was arranged, has N oscillating tooth (17) equipartition on the face cam, and every oscillating tooth (17) is installed respectively in a guide way (21) of casing (1), and every oscillating tooth (17) all can follow guide way (21) at place and reciprocate, the lower extreme of oscillating tooth (17) with face ring gear (20) meshing, including 2N +2 same tooth (201) on the fluted disc of face ring gear (20), face ring gear (20) with output disc (14) are connected firmly.

2. The multi-stage coaxial surface contact oscillating tooth precision reducer according to claim 1, characterized in that: the teeth (201) on the fluted disc of the face gear ring (20) are circumferentially and uniformly distributed on the end face of the face gear ring (20), the working curve shape of the teeth (201) comprises symmetrical cylindrical spiral lines (204) with opposite rotation directions, and in order to avoid top cutting, two sections of the cylindrical spiral lines (204) are in transition curve connection;

the tooth form of the movable teeth (17) is the same as that of the teeth (201) on the fluted disc of the face gear ring (20); the theoretical profile of the surface cam of the shock wave device (3) is formed by sequentially connecting two sections of ascending working curves, two sections of descending working curves and four sections of transition curves, wherein the ascending working curves and the descending working curves are cylindrical spiral lines with the same tooth profile lift range as that of the surface gear ring (20) and smaller lead, each section of transition curve is tangent to the front section of working curve and the rear section of working curve, any point of the transition curve has a derivative, and the function of the transition curve is to enable the up-and-down movement of the movable teeth (17) to be in smooth transition so as to prevent impact.

3. The multi-stage coaxial movable tooth surface contact precision reducer of claim 1, wherein: the movable teeth (17) are in contact with the surface cam, the phases are different, the height position of each movable tooth (17) is different at the same time, the movable teeth (17) are in clearance fit with the guide grooves (21), and the movable teeth (17) can move up and down along the guide grooves (21) and are used for achieving axial guide.

4. The multi-stage coaxial movable tooth surface contact precision reducer of claim 1, wherein: one or two contact planes are arranged on the side surface contact surface of the movable tooth (17) and the guide groove (21) and are used for realizing circumferential positioning.

5. The multi-stage coaxial surface contact oscillating tooth precision reducer according to claim 1, characterized in that: and oil seals (15) are arranged between the face gear ring (20) and the shell (1) and between the output disc (14) and the shell (1).

6. The multi-stage coaxial surface contact oscillating tooth precision reducer according to claim 1, characterized in that: and a shaft sleeve (19) is arranged on the crank shaft (5) and positioned between the eccentric disc bearing (6) and the crank shaft bearing (4).

7. The multi-stage coaxial surface contact oscillating tooth precision reducer according to claim 1, characterized in that: the rotation of the shock wave device (3) is driven by the revolution of the eccentric disc (12), the revolution of the eccentric disc (12) is driven by the crank shaft (5), and the eccentric disc (12) is used for connecting a planetary gear train of a high-speed stage and a movable tooth speed reducer of a low-speed stage.

8. The multi-stage coaxial movable tooth surface contact precision reducer according to claim 1, characterized in that the profiles of the teeth (201) on the fluted disc of the face gear ring (20), the movable teeth (17) and the face cam of the shock wave generator (3) adopt the following cylindrical helical lines,

the parametric equation for the cylindrical helix is as follows:

in the formula, r is the distance between a certain point on the movable tooth (17) or the face gear ring (20) and the central axis of the face gear ring (20), h is the height of a circle of cylindrical spiral line which rises, called the pitch, theta is the angle rotated by the point relative to the initial point, and x, y and z are the coordinate position of the point.

Technical Field

The invention relates to the field of transmission mechanisms, in particular to the field of movable tooth transmission and the field of precision transmission, and particularly relates to a multistage coaxial surface contact movable tooth precision speed reducer.

Background

With the continuous advance of science and technology to the extreme working condition field, especially fields such as robot, aviation have proposed the requirement of zero clearance precision, big velocity ratio, high bearing, long-life to accurate reduction gear. The precision speed reducer in the existing market takes an RV speed reducer and a harmonic speed reducer as main parts.

The RV reducer is a two-stage reducer developed by the company of the Kidi Japan in the last 80 th century based on the principle of small tooth difference, and has the advantages of large speed ratio, high precision, stable transmission and the like, but the low-speed reducer is sensitive to machining errors and high in machining difficulty, and most importantly, the improved scheme based on the RV reducer cannot meet the expected requirement before the requirement of improving the bearing capacity.

The harmonic reducer is also a precision reducer based on the principle of small tooth difference, and can realize larger transmission ratio output, however, the harmonic reducer realizes the mode of small tooth difference by periodically extruding the flexible gear through the shock wave device, so that the efficiency, the precision and the service life of the harmonic reducer are influenced in the operation process, and the harmonic reducer is easy to fail under the working condition of complex dynamics.

Disclosure of Invention

The object of the present invention is to achieve a precision reducer that meets the requirements mentioned in the background section. The speed reducer eliminates the defects of the existing precision speed reducer, wherein the speed reducer has higher torque transmission capacity than the existing precision speed reducer under the same size in a surface contact meshing mode in the link with larger torque in the force transmission process. In addition, under the condition of high torque transmission capacity, the gear ratio range which can be selected by the accelerator is large, and the gear ratio range can be arbitrarily selected from i-10 to i-150. At higher torque transmission capacity and higher gear ratios, the inventive gear unit can carry an input speed of at least 10000 rpm.

In order to realize the speed reducer meeting the requirements, the invention provides a multistage coaxial surface contact oscillating tooth precision speed reducer which consists of a high-speed input component, a low-speed output component and a shell, wherein the high-speed input component comprises an input shaft, a central gear fixedly connected with the input shaft, three planetary gears uniformly distributed in the circumferential direction and crank shafts respectively fixedly connected with the three planetary gears, and an eccentric disc and a shock wave device are sleeved on the three crank shafts; the low-speed output component consists of movable teeth, a face gear ring and an output disc; the input shaft, the central gear, the shock wave device, the shell, the face gear ring and the output disc are coaxially arranged; the high-speed input component is a planetary gear train, and the low-speed output component is a movable tooth speed reducer; the high-speed input component and the low-speed output component form a K-H-V type epicyclic gear train together; the input shaft is used for bearing high-speed input motion, three planetary gears which are uniformly distributed in the circumferential direction are meshed with the central gear at the same time, the crank directions of three crankshafts are consistent and are positioned in three stepped holes which are uniformly distributed in the circumferential direction on the eccentric disc, and the eccentric disc is placed on the shock wave device; the utility model discloses a face gear, including the input dish, be equipped with N guide way on the casing, the lower extreme of shock wave ware has the face cam that circumference was arranged, has N oscillating tooth equipartition on the face cam, and every oscillating tooth is installed respectively in a guide way of casing, and every oscillating tooth all can follow the guide way at place and reciprocate, the lower extreme of oscillating tooth with the meshing of face ring gear, including 2N +2 the same teeth on the fluted disc of face ring gear, face ring gear with the output dish links firmly.

Further, the multistage coaxial surface contact oscillating tooth precision speed reducer of the invention is characterized in that teeth on the tooth disc of the face tooth ring are uniformly distributed on the end face of the face tooth ring in the circumferential direction, the working curve shape of the teeth comprises symmetrical cylindrical spiral lines with opposite rotation directions, and in order to avoid top cutting, two sections of the cylindrical spiral lines are connected by a section of transition curve, namely, a part is cut off at the tooth top; the tooth form of the movable teeth is the same as that of the teeth on the face ring gear plate; the theoretical profile of the face cam of the shock wave device is formed by sequentially connecting two sections of ascending working curves, two sections of descending working curves and four sections of transition curves, wherein the ascending working curves and the descending working curves are cylindrical spiral lines with smaller lead equal to the tooth profile lift of the face gear ring, each section of transition curve is tangent to the front section of working curve and the rear section of working curve and is smooth, the curve function of the transition curve is arbitrarily taken, but any point of the transition curve has a derivative, the curves are distributed in the circumferential direction to be sequentially circulated from the ascending curve to the transition curve to the descending curve to the transition curve, and the transition curve has the function of enabling the movable teeth to move up and down in a smooth transition mode to prevent impact.

The movable teeth are in contact with the face cam, the phases are different, the height position of each movable tooth is different at the same time, the movable teeth are in clearance fit with the guide grooves, and the movable teeth can move up and down along the guide grooves and are used for achieving axial guiding.

One or two contact planes are arranged on the contact surface of the side surface of the movable tooth and the guide groove and are used for realizing circumferential positioning.

And oil seals are arranged between the face gear ring and the shell, and between the output disc and the shell.

And a shaft sleeve is arranged on the crank shaft between the eccentric disc bearing and the crank shaft bearing.

The rotation of the shock wave device is driven by the revolution of the eccentric disc, the revolution of the eccentric disc is driven by the crank shaft, and the eccentric disc is used for connecting the high-speed planetary gear train and the low-speed oscillating tooth speed reducer.

The profiles of the teeth on the face gear ring fluted disc, the movable teeth and the face cam of the shock wave device adopt the following cylindrical spiral lines,

the parametric equation for the cylindrical helix is as follows:

in the formula, r is the distance between a certain point on the movable tooth or the face gear ring and the central axis of the face gear ring, h is the height of a circle of cylindrical spiral line which rises, called the thread pitch, theta is the angle of the point which rotates relative to the initial point, and x, y and z are the coordinate position of the point.

Compared with the prior art, the invention has the beneficial effects that:

in the speed reducer, a shell is fixed, high-speed rotation is input by a central gear which is coaxial with the shell, the central gear is meshed with three planetary gears, each planetary gear is fixedly connected with a crank shaft, three crank shafts which are offset in the same direction and an eccentric disc form a rotating pair, the eccentric disc is placed on a shock wave device to push the shock wave device to rotate automatically, movable teeth are driven to move axially and meshed with a face gear ring, so that the face gear ring rotates at low speed, the face gear ring is fixedly connected with an output disc, and the output disc outputs low-speed rotation. The speed reducer adopts an axial shock wave and multi-tooth meshing mode, and compared with a common speed reducer, the speed reducer has the advantages of large speed ratio, compact structure and convenience in manufacture. The speed reducer has the advantages of high bearing capacity, uniform output, high rigidity, stable transmission, high reliability and the like, and can meet the requirements of the speed reducer on occasions with high speed ratio, high bearing capacity and low return difference.

Drawings

FIG. 1 is a schematic cross-sectional view of a multi-stage coaxial surface contact oscillating tooth precision reducer of the present invention;

FIG. 2 is an isometric view containing only the oscillating tooth 17 and the face ring gear 20;

FIG. 3 is a schematic perspective view of the tooth flank formation of the face ring gear 20 shown in FIG. 1;

FIG. 4 is a schematic side view of the oscillating tooth 17 shown in FIG. 1;

FIG. 5 is a top view containing only the oscillating tooth 17 and the face ring gear 20;

FIG. 6 is an isometric view of a multi-stage coaxial face contact oscillating tooth precision reducer of the present invention;

in the figure: 1-shell, 2-main bearing, 3-shock absorber, 4-crank shaft bearing, 5-crank shaft, 6-eccentric disc bearing, 7-planetary gear, 8-input shaft, 9-central gear, 10-input shaft small bearing, 11-fixing bolt, 12-eccentric disc, 13-eccentric disc roller, 14-output disc, 15-oil seal, 16-shock absorber roller, 17-oscillating tooth, 18-input shaft large bearing, 19-crank shaft sleeve, 20-face gear ring and 21-oscillating tooth guide groove.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

As shown in fig. 1 and fig. 6, the multi-stage coaxial surface contact oscillating tooth precision speed reducer provided by the present invention is composed of a high speed input member, a low speed output member and a housing 1, wherein the high speed input member comprises an input shaft 8, a central gear 9 fixedly connected with the input shaft 8, three planetary gears 7 uniformly distributed in the circumferential direction and crank shafts 5 respectively fixedly connected with the three planetary gears 7, that is, each planetary gear 7 is fixedly connected with one crank shaft 5, and the three crank shafts 5 are sleeved with an eccentric disc 12 and a shock wave device 3 driven by the eccentric disc 12; the low-speed output component consists of a movable tooth 17, a face ring gear 20 and an output disc 14; the input shaft 8, the central gear 9, the shock wave device 3, the shell 1, the face gear ring 20 and the output disc 14 are coaxially arranged.

The high-speed input component is a planetary gear train, and the low-speed output component is a movable tooth speed reducer; the high-speed input member and the low-speed output member jointly form a K-H-V type epicyclic gear train. The input shaft 8 is used for bearing high-speed input motion, the central gear 9 is fixedly connected with the input shaft 8 through a spline, as shown in fig. 6, three planetary gears 7 which are uniformly distributed in the circumferential direction are simultaneously meshed with the central gear 9, the crank directions of three crankshafts 5 are consistent and are positioned in three stepped holes which are uniformly distributed in the circumferential direction on the eccentric disc 12, the eccentric disc 12 is placed on the shock absorber 3 through an eccentric disc roller 13, the shock absorber 3 is placed on the shell 1 through a shock absorber roller 16, and the positions of the eccentric disc 12 and the shock absorber 3 where the eccentric disc roller 13 is placed are inclined planes. The shock 3 and the housing 1 are also beveled at the location where the shock roller 16 is placed.

The utility model discloses a face gear ring 20, including casing 1, be equipped with N guide way 21 that is used for oscillating tooth axial direction on the casing 1, the lower extreme of shock wave ware 3 has the face cam that circumference was arranged, has N oscillating tooth 17 equipartition on the face cam, and every oscillating tooth 17 is installed respectively in one guide way 21 of casing 1, and every oscillating tooth 17 all can follow the guide way 21 at place and reciprocate, the lower extreme of oscillating tooth 17 with face ring gear 20 meshes, including 2N +2 the same tooth 201 on the fluted disc of face ring gear 20, face ring gear 20 with output disc 14 passes through bolt 11 and links firmly. The inner gear ring 20 and the output disc 14 are respectively placed on the shell 1 through a main bearing 2 and are fixed and pre-tightened through three circumferentially uniformly distributed bolts, and the main bearings 2 are in face-to-face contact.

In the invention, the input shaft 8 is designed into a step-shaped hollow shaft, and is placed on the output disc 14 and the face gear ring 20 through the input shaft small bearing 10 and the input shaft large bearing 18, and the input shaft small bearing 10 and the input shaft large bearing 18 are tapered roller bearings with opposite directions and are installed face to face. Each crank shaft 5 is placed on the output disc 14 and the face ring gear 20 by two crank shaft bearings 4 and on the eccentric disc 12 by one eccentric disc bearing 6, wherein the two crank shaft bearings 4 are tapered roller bearings with opposite directions, and are installed face to face, and the eccentric disc bearing 6 is an angular contact ball bearing with an upward direction. The crankshaft 5 is provided with a shaft sleeve 19 between the eccentric disc bearing 6 and the crankshaft bearing 4, and the shaft sleeve 19 is used for providing axial positioning of the crankshaft bearing 4 at the lower end, thereby axially fixing the crankshaft 5. And oil seals 15 are arranged between the face gear ring 20 and the shell 1 and between the output disc 14 and the shell 1, and the oil seals 15 play a role in sealing.

As shown in fig. 3, the teeth 201 on the toothed disc of the face gear ring 20 are uniformly distributed on the end face of the face gear ring 20 in the circumferential direction, the working curve shape of the teeth 201 includes symmetrical cylindrical spiral lines 204 with opposite rotation directions, in order to avoid top cutting, two sections of cylindrical spiral lines 204 are connected by a section of transition curve, an adjacent section of ascending cylindrical spiral line and an adjacent section of descending cylindrical spiral line are connected by a section of transition curve, that is, a part 206 is cut off at the top of the teeth 201, and the bottom end of the joint of the two teeth 201 is filled with a filler 205; the tooth form of the movable teeth 17 is the same as that of the teeth 201 on the fluted disc of the face gear ring 20. The theoretical profile of the face cam of the shock wave device 3 is formed by sequentially connecting two sections of ascending working curves, two sections of descending working curves and four sections of transition curves, wherein the ascending working curves and the descending working curves are cylindrical spiral lines which are equal to the tooth profile lift of the face gear ring 20 and are more gentle, namely, the lead is smaller, each section of transition curve is tangent to the front section of working curve and the rear section of working curve and is smooth, the curve function of the transition curve is arbitrarily taken, but any point is required to have a derivative, the curves are arranged in the circumferential direction to be sequentially circulated from the ascending curve to the transition curve to the descending curve, and the face contact between the movable teeth 2 and the face gear ring 4 can be realized through the mode. The function of the transition curve is to make the up-and-down movement of the movable teeth smoothly transited to prevent the occurrence of impact.

As shown in fig. 4, the main body of the movable tooth 17 is a cylindrical body, the upper end of the main body is provided with a spherical surface 171, the lower end of the main body is provided with teeth 172 having the same tooth form as that of the teeth 201 on the toothed disc of the face gear ring 20, and in order to prevent top cutting, a section of ascending working curve and a section of descending working curve of the movable tooth are connected by a transition curve, namely, a part 173 is cut off at the lower end part of the movable tooth 17. The movable teeth 17 are in contact with the surface cam, the phases are different, the height position of each movable tooth 17 is different at the same time, the movable teeth 17 are in clearance fit with the guide grooves 21, and the movable teeth 17 can move up and down along the guide grooves 21 and are used for achieving axial guide. One or two contact planes are arranged on the side contact surface of the movable tooth 17 and the guide groove 21 and are used for realizing circumferential positioning.

In the invention, the corresponding end surface of the oscillating tooth 17 is contacted with the surface cam on the shock wave device 3, the surface cam is a circumferential curved surface guided by a closed annular curve, and the oscillating tooth 17 can be pushed to move up and down when the shock wave device 3 rotates.

In the present invention, the rotation of the shock device 3 is driven by the revolution of the eccentric disc 12, the revolution of the eccentric disc 12 is driven by the crank shaft 5, and the eccentric disc 12 is used for connecting the planetary gear train of the high speed stage and the oscillating tooth reducer of the low speed stage.

The speed reducer of the invention realizes the speed reduction function in the following way: the high-speed input motion is input to a sun gear 9 of the planetary gear train, and the sun gear 9 transmits the motion to the planetary gear 7 and the crankshaft 5 to realize first speed reduction; the crank shaft 5 drives the eccentric disc 12 to revolve around the central axis of the shock wave device 3 to drive the shock wave device 3 to rotate, the shock wave device 3 drives the movable teeth 17 to move up and down through the surface cam on the end surface, and the movable teeth 17 push the surface gear ring 20 to rotate through the complex curved surface of the lower end surface to realize secondary speed reduction.

The purpose of improving weak links in the existing speed reducer force transmission process is achieved through the following mode, the movable teeth 17 and the face gear ring 20 of the speed reducer have complex tooth profiles, and the profiles of the teeth 201 on the toothed disc of the face gear ring 20, the movable teeth 17 and the face cam of the shock wave generator 3 all adopt cylindrical spiral lines, so that the movable teeth 17 can be in curved surface-to-surface contact with the face gear ring 20.

The parametric equation for the cylindrical helix is as follows:

in the formula, r is the distance between a certain point on the movable tooth 17 or the face gear ring 20 and the central axis of the face gear ring 20, h is the height of a circle of cylindrical spiral line which rises, called the pitch, theta is the angle of the circle of the point relative to the initial point, x, y and z are the coordinate positions of the point, and the cylindrical spiral line 204 is the profile of the face gear ring 20.

The working positions of the end surfaces of the movable teeth 17 and the teeth 201 on the fluted disc of the face gear ring 20 and the meshing end surface of the movable teeth 17 are processed into cylindrical spiral lines, so that the movable teeth 17 and the face gear ring 20 are in face contact in the working process, the pressure born by the contact positions is reduced, in addition, the multiple groups of movable teeth 17 are ensured to be uniformly distributed in the circumferential direction, under the driving of the shock wave device 3, a plurality of movable teeth 17 are meshed with the face gear ring 20 at any time, and particularly, the movable teeth 17 are positioned at different phases in the same up-down moving period. Through the mode, the transmission of the increased torque can be ensured on the premise of uniform abrasion.

The surface cam of the shock wave device 3 is a closed curved surface formed by a plurality of sections in sequence, the sections can be classified into a lift section, a return section and a transition section, and the sections sequentially appearing on the surface cam are the lift section, the transition section, the return section, the transition section, the lift section and the like. The lift section has the main function of pushing the movable teeth to move downwards, the theoretical profile of the lift section is a cylindrical spiral line, and the difference between the theoretical profile of the lift section and the cylindrical spiral line on the face gear is that the parameter equation of a z coordinate is as follows

Wherein i is the transmission ratio between the shock wave device and the face gear ring, and is usually selected between 10 and 40. The main function of the return segment is to guide the movable teeth to be disengaged upwards, the theoretical profile of the return segment is also a cylindrical spiral line, and the difference from the lift segment is the parameter of the z coordinateThe equation is in the form of

The minus sign indicates that the height direction is opposite to the lift section. The transition section is a curve connecting the lift section and the return section, and mainly has the main functions of preventing the impact caused by sudden speed change due to the axial speed of the movable teeth between the transition section and the return section, and the theoretical profile of the transition section can be selected at will but meets the conditions that: the curve is continuous and smooth and tangent to the lift section and the return section, and for example, an arc tangent to both the lift section and the return section can be selected. The actual profile of the face cam can be any curved surface swept by a smooth curve along the theoretical profile, for example, a curved surface formed by a circle swept by the theoretical profile, and at the same time, the end face of the oscillating tooth should be a hemisphere with a radius equal to that of the circle.

As shown in fig. 1, when the speed reducer works, the high-speed rotation input by the motor is directly transmitted to the input shaft 8, the input shaft 8 and the central gear 9 rotate together at high speed, the central gear 9 drives the planet gears 7 and the crank shafts 5 to rotate, the three crank shafts 5 jointly act on the eccentric disc 12 to enable the eccentric disc 12 to revolve around the central shaft of the shock device 3, the shock device 3 drives the movable teeth 17 to move up and down through the face cam positioned below, the movable teeth 17 are meshed with the face ring gear 20 to drive the face ring gear 20 to rotate at low speed, and the face ring gear 20 is fixedly connected with the output disc 14 to output the low-speed rotation. Since the planetary gears 7 are located on the output disc 14, the planetary gears 7 revolve with the output disc 14, thereby forming a closed structure. Throughout the movement, the housing 1 is stationary.

As shown in fig. 2, 3, 4 and 5, the toothed disc of the face ring gear 20 is composed of a plurality of identical non-repeating wheels uniformly distributed on a ring, and the movable teeth 17 are also uniformly distributed on the ring, and generally, the number of the movable teeth 17 is one half of the number of the non-repeating teeth. The shape of the teeth 201 of the fluted disc is the same as that of the movable teeth, and on a circular ring with the same radius of the central axis of the face ring gear 20, the curve of the single non-repeated teeth 201 and the movable teeth 17 consists of two cylindrical spiral lines with the same lead and the opposite rotation directions. The cylindrical helical leads on the face gear 20 and the oscillating tooth 17 are still equal at different radii.

In the present invention, it is preferable that the guide groove 21 of the movable tooth 17 is formed integrally with the housing 1 to reduce assembly error.

The foregoing description is only exemplary of the preferred embodiments of the invention and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the invention herein disclosed is not limited to the particular combination of features described above, but also encompasses other arrangements formed by any combination of the above features or their equivalents without departing from the spirit of the invention. For example, the above features and (but not limited to) features having similar functions disclosed in the present invention are mutually replaced to form the technical solution.