CN113374852A - Movable tooth harmonic speed reducer - Google Patents

Abstract

The invention discloses a movable tooth harmonic reducer. The mechanism is composed of a positioning shaft, a flexible wheel, a cross bearing, a screw, a casing, a needle roller, a flexible bearing, an input shaft, etc. The inner cylindrical surface of the casing is processed with a plurality of arcs Grooved teeth, a needle roller is installed in the arc groove, the flexible bearing is installed on the outer surface of the input shaft, the flexible bearing is installed in the flexible wheel, the outer surface of the flexible bearing is in contact with the inner surface of the flexible wheel, the indexing circle of the flexible wheel tooth is an ellipse, The teeth on the flex wheel mesh with the needle rollers. The flexible wheel is connected with the cross bearing by bolts. The advantages and beneficial effects of the patent of the present invention are: the reducer is simple, compact and easy to miniaturize; it has low requirements on machining accuracy and low noise; at the same time, the number of teeth involved in meshing is large, and the bearing capacity is strong; under the radial preload condition of the meshing pair, The deceleration meshing pair is in a gapless meshing state, with high transmission precision; the needle roller and the cycloidal tooth are meshed purely by rolling, with high transmission efficiency and low wear rate of the meshing surface.

Description

A movable tooth harmonic reducer

technical field

The invention relates to the field of mechanical transmission, in particular to a movable tooth harmonic reducer.

Background technique

Harmonic reducer, also known as harmonic reducer or harmonic drive reducer, is a reducer developed using the principle of planetary gears. Its structure includes a rigid gear with an internal gear ring (equivalent to a Central wheel rigid wheel), flexible gear with outer ring gear (equivalent to planetary gear) and wave generator (equivalent to planet carrier). Used as a reducer, its working principle is that the wave generator is a rod-shaped component, and rolling bearings are installed at both ends to form a roller, which is pressed against the inner wall of the flexible wheel. The flexible wheel is a thin-walled gear that can produce large elastic deformation, and its inner hole diameter is slightly smaller than the total length of the wave generator. The wave generator is a component that makes the flexible wheel produce controllable elastic deformation. When the wave generator is installed in the flex wheel, the cross section of the flex wheel is forced to change from the original circle to an ellipse, and the teeth near the two ends of the long axis are fully meshed with the teeth of the rigid wheel, while the teeth near the two ends of the short axis are Completely disengage from the wheel. The teeth of other segments on the perimeter are in a transitional state of engagement and disengagement. When the wave generator rotates continuously in the direction shown in the figure, the deformation of the flexible wheel changes continuously, so that the meshing state of the flexible wheel and the rigid wheel also changes continuously, from meshing, meshing, meshing out, disengaging, and meshing again..., Repeatedly, so as to realize the slow rotation of the flexible wheel relative to the rigid wheel in the opposite direction of the wave generator. When working, the rigid wheel is fixed, the motor drives the wave generator to rotate, and the flexible wheel acts as a driven wheel, and the output rotates to drive the load to move.

The harmonic reducer has the advantages of precise transmission technology and easy miniaturization, but the flexible wheel realizes meshing transmission based on the macro-elastic deformation of the cylinder material, which restricts the harmonic reducer in the field of high power and heavy load. development application.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and to provide a movable tooth harmonic reducer. The technical solution is to process a plurality of circular arc teeth on the outer casing, and the outer cylindrical surface of the flexible wheel is processed with a plurality of teeth. The input shaft is of axisymmetric structure, and the meshing pair can reach the state of multi-tooth meshing. The structure is simple and compact, with strong bearing capacity and high efficiency, and can realize precise transmission.

In order to achieve the above purpose, the technical scheme of the present invention includes a positioning shaft, a flexible wheel, a cross bearing, a casing, a needle roller, a flexible bearing and an input shaft;

The input shaft is provided with an outer surface for realizing the function of the wave generator, and the outer surface is a first elliptical curved surface;

A flexible bearing is installed on the input shaft, the inner surface of the flexible bearing is a second elliptical curved surface, and the second elliptical curved surface coincides with the equidistant offset surface of the first elliptical curved surface of the input shaft;

The inner cylindrical surface of the shell is machined with Z ₂ arc groove teeth, the diameter is d ₁ , Z ₂ arc groove teeth are evenly distributed on a circle with a radius R, and a diameter d _r is installed in the arc groove. Needle roller, d _r <d ₁ ;

The flexible wheel includes a flexible wheel tooth portion, a flexible wheel transition portion and a flexible wheel positioning portion connected along the axial direction;

The flexible bearing is in contact with the inner surface of the flex wheel tooth portion, and the outer surface of the flex wheel tooth portion is machined with Z ₁ teeth. The theoretical tooth shape of the flex wheel tooth portion is as follows:

ε＝θ-φ，

a为椭圆长半轴，b为椭圆段半轴，θ根据下式求解in,

ε=θ-φ,

a is the semi-major axis of the ellipse, b is the semi-axis of the ellipse segment, and θ is solved according to the following formula

φ∈[0,2Z₂π)；in,

φ∈[0,2Z ₂ π);

The actual tooth shape of the flex wheel is the equidistant offset line of the theoretical tooth shape of the flex wheel, and its equidistant offset distance is d _r -d ₁ /2;

The index circle of the teeth of the flexible gear tooth portion is an ellipse;

The flexible bearing is installed on the outer surface of the input shaft, the teeth of the flexible wheel are connected to the outside of the flexible bearing by contact and force, the outer surface of the flexible bearing is in contact with the inner surface of the teeth of the flexible wheel, and the teeth on the flexible wheel are in contact with the needle roller to form a partial meshing fit;

The flex wheel positioning part is fixed on the inner ring of the cross bearing; the positioning shaft is supported and positioned in the flex wheel positioning part and the inner hole of the inner ring of the cross bearing to ensure the connection between the flex wheel and the cross bearing. Coaxiality; the outer ring of the cross bearing is fixedly connected with the end face of the housing.

Through the above settings, the input shaft pushes the flex wheel to radially deform through the flexible bearing, the outer cylindrical teeth of the flex wheel mesh with the needle roller, and the input shaft rotates to realize the continuous elliptical change of the flex wheel. Pure rolling on the surface, the needle slides in the arc groove teeth, the motion trajectory is an arc, and the diameter of the arc is d ₁ -d _r . All teeth are engaged in meshing to achieve the purpose of strong bearing capacity of the reducer. The needle roller and the tooth surface are in pure rolling contact to achieve the purpose of high transmission efficiency.

The further setting is the equidistant offset line of the theoretical tooth shape of the flexible wheel, so that the equidistant offset distance is less than d _r -d _1/2 , so as to realize the precise transmission and long life of the reducer.

It is further provided that the inner side of the corresponding needle roller on the casing is provided with a baffle plate that restricts the axial movement of the needle roller, and the outer side of the outer casing corresponding to the needle roller is provided with a baffle ring that restricts the radial and axial movement of the needle roller.

A further arrangement is that the center of the input shaft is provided with a keyway for accessing the power to be decelerated.

It is further provided that the flexible wheel positioning portion is fixed on the inner ring end face of the cross bearing by means of bolts.

It is further provided that the outer ring of the cross bearing is fixed on the end face of the housing by screws.

Further settings are that Z ₂ is 100, Z ₁ is 98, a=21.92mm, b=21.4mm.

Through the above structure, the input shaft rotates, the input shaft pushes the flex wheel through the flexible bearing to produce deformation, the flex wheel pushes the needle roller, the needle roller reacts to the flex wheel, the flex wheel rotates at a low speed under the action of the input shaft and the limit of the needle roller, and the needle roller rotates in a circle. The arc groove slides and rolls, the flexible wheel drives the inner ring of the cross bearing to rotate, and the output shaft power realizes the deceleration movement of the reducer.

gear ratio

The advantages and beneficial effects of the patent of the present invention are: the reducer is simple, compact and easy to miniaturize; the flexible wheel is an elastic part, and elastic deformation occurs during the meshing process, which requires low machining accuracy and low noise; The inner needle contacts the flex wheel tooth shape in real time, so that all the teeth are engaged in meshing, so as to achieve the purpose of strong bearing capacity; the theoretical tooth shape equidistant offset distance of the flex wheel is less than d _r -d ₁ /2, so that the meshing pair is in a pre-tightening position , to eliminate the backlash and achieve the purpose of precision transmission and long life; the diameter of the circular arc groove teeth is larger than the diameter of the needle roller, so that the diameter of the needle roller can rotate in the circular arc groove teeth, and the pure rolling contact between the needle roller and the teeth on the flexible wheel is realized , to achieve the purpose of high transmission efficiency and low wear rate of the meshing surface.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, obtaining other drawings according to these drawings still belongs to the scope of the present invention without any creative effort.

Figure 1 is a schematic diagram of the structure of the movable tooth harmonic reducer;

Figure 2. Sectional view of the deceleration meshing pair of the movable tooth harmonic reducer;

Figure 3 is a schematic diagram of the flexible wheel structure of the movable tooth harmonic reducer;

Figure 4 is a schematic diagram of the housing structure of the movable tooth harmonic reducer;

Figure 5 is a diagram of the theoretical tooth shape of the outer surface of the tooth portion of the flexible gear of the present invention;

Figure 6 is a schematic diagram of the input shaft structure of the movable tooth harmonic reducer.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities with the same name but not the same or non-identical parameters. It can be seen that "first" and "second" It is only for the convenience of expression and should not be construed as a limitation to the embodiments of the present invention, and subsequent embodiments will not describe them one by one.

The directional and positional terms mentioned in the present invention, such as "up", "down", "front", "rear", "left", "right", "inside", "outside", "top", "bottom" ”, “sideways”, etc., only refer to the orientation or position of the drawings. Therefore, the directional and positional terms used are for describing and understanding the present invention, rather than limiting the protection scope of the present invention.

As shown in FIGS. 1 to 6 , in the embodiment of the present invention, it includes an input shaft 1 , a flexible wheel 2 , a cross bearing 3 , a housing 4 , a needle roller 5 , a flexible bearing 6 and a positioning shaft 7 .

The input shaft 1 described in this embodiment is provided with an outer surface for realizing the function of the wave generator, and the outer surface is a first elliptical curved surface 11 . The input shaft 1 is provided with a flexible bearing 6, and the inner surface of the flexible bearing 6 is a second elliptical curved surface 61, which coincides with the equidistant offset surface of the first elliptical curved surface 11 of the input shaft.

The inner cylindrical surface of the housing 4 described in the present embodiment is machined with Z ₂ circular arc groove teeth, the diameter is d ₁ , the Z ₂ circular arc groove teeth are evenly distributed on the circle with the radius R, and the circular arc groove is installed with a diameter d 1 . It is the needle roller of _{dr, d r <} d ₁ ; as preferably, 100 arc groove teeth 41 are machined on the inner cylindrical surface of the housing 4 in this embodiment, the diameter is 1.01 mm, and the 100 arc groove teeth 41 are evenly distributed in the On a circle with a radius of 21.656mm, a needle roller 5 with a diameter of 1mm is installed in the arc groove.

In addition, the flex wheel 2 described in this embodiment includes a flex wheel tooth portion 21 , a flex wheel transition portion 22 and a flex wheel positioning portion 23 connected along the axial direction.

The flexible bearing 6 is in contact and force-fitted with the inner surface of the flex wheel tooth portion 21. The outer surface of the flex wheel tooth portion 21 is machined with Z ₁ teeth. In this embodiment, Z ₁ is 98. The theoretical tooth shape of the surface is the flex wheel, and the theoretical tooth shape is:

角差ε＝θ-φ，偏心率

a为椭圆长半轴，b为椭圆段半轴，等长角θ根据下式求解Among them, the vector diameter

Angular difference ε=θ-φ, eccentricity

a is the semi-major axis of the ellipse, b is the semi-axis of the ellipse segment, and the equal-length angle θ is solved according to the following formula

自变量φ∈[0,2Z₂π)。本实施例优选设置是a＝21.92mm，b＝21.4mm。Among them, rounded corners

The independent variable φ∈[0,2Z ₂ π). The preferred settings in this embodiment are a=21.92mm, b=21.4mm.

The actual tooth shape of the outer surface of the flex wheel tooth portion 21 is the equidistant offset line of the theoretical tooth shape of the flex wheel, and its equidistant offset distance is d _r -d ₁ /2; in this embodiment, there are sections, the equidistant offset The distance is 0.495mm, and the index circle of the teeth of the flex wheel tooth portion is an ellipse.

In this embodiment, the flexible bearing 6 is installed on the outer surface of the input shaft 1, the flex wheel tooth portion 21 is connected to the outside of the flexible bearing 6 by contact and force, the outer surface of the flexible bearing 6 is in contact with the inner surface of the flex wheel tooth portion 21, and the teeth on the flex wheel 2 The contact with the needle roller 5 is forced to form a partial engagement.

In addition, the flex wheel positioning portion 23 in this embodiment is fixed on the inner ring of the cross bearing 3 through bolts 81 ; the positioning shaft 7 is supported and positioned on the flex wheel positioning portion 23 and the inner ring of the cross bearing 3 . In the inner hole, it is used to ensure the coaxiality of the flexible wheel 2 and the cross bearing 3; the outer ring of the cross bearing 3 is fixedly connected with the end face of the casing 4 through screws 82, and the casing 4 corresponds to the position of the needle roller 5. The inner side is provided with a baffle 83 that restricts the axial movement of the needle roller, and the outer side of the outer casing 4 corresponding to the needle roller 5 is provided with a baffle ring 84 that restricts the radial and axial movement of the needle roller 5. The center is provided with a keyway 12 for accessing the power to be decelerated.

Through the above settings, the input shaft 1 rotates, the input shaft 1 pushes the flex wheel 2 through the flexible bearing 6 to deform, the flex wheel 2 pushes the needle 5, the needle 5 reacts to the flex wheel 2, and the flex wheel 2 pushes the input shaft 1 and the needle roller 5. Low-speed rotation under the action of restriction, the needle roller 5 slides in the arc groove, the flexible wheel 2 drives the inner ring of the cross bearing to rotate, and outputs the power of the shaft to realize the deceleration movement of the reducer.

its gear ratio

The above disclosures are only preferred embodiments of the present invention, and of course, the scope of the rights of the present invention cannot be limited by this. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims (6)

1. a movable tooth harmonic reducer is characterized in that: Including as positioning shaft, flexible wheel, cross bearing, housing, needle roller, flexible bearing and input shaft; The input shaft is provided with an outer surface for realizing the function of the wave generator, and the outer surface is a first elliptical curved surface; A flexible bearing is installed on the input shaft, the inner surface of the flexible bearing is a second elliptical curved surface, and the second elliptical curved surface coincides with the equidistant offset surface of the first elliptical curved surface of the input shaft; The inner cylindrical surface of the shell is machined with Z ₂ arc groove teeth, the diameter is d ₁ , Z ₂ arc groove teeth are evenly distributed on a circle with a radius R, and a diameter d _r is installed in the arc groove. Needle roller, d _r <d ₁ ; The flexible wheel includes a flexible wheel tooth portion, a flexible wheel transition portion and a flexible wheel positioning portion connected along the axial direction; The flexible bearing is in contact with the inner surface of the flex wheel tooth portion, and the outer surface of the flex wheel tooth portion is machined with Z ₁ teeth. The theoretical tooth shape of the flex wheel tooth portion is as follows:

in,

ε=θ-φ,

a is the semi-major axis of the ellipse, b is the semi-axis of the ellipse segment, and θ is solved according to the following formula

in,

φ∈[0,2Z ₂ π); The actual tooth shape of the flex wheel is the equidistant offset line of the theoretical tooth shape of the flex wheel, and its equidistant offset distance is d _r -d ₁ /2; The index circle of the teeth of the flexible gear tooth portion is an ellipse; The flexible bearing is installed on the outer surface of the input shaft, the teeth of the flexible wheel are connected to the outside of the flexible bearing by contact and force, the outer surface of the flexible bearing is in contact with the inner surface of the teeth of the flexible wheel, and the teeth on the flexible wheel are in contact with the needle roller to form a partial meshing fit; The flex wheel positioning part is fixed on the inner ring of the cross bearing; the positioning shaft is supported and positioned in the flex wheel positioning part and the inner hole of the inner ring of the cross bearing to ensure the connection between the flex wheel and the cross bearing. Coaxiality; the outer ring of the cross bearing is fixedly connected with the end face of the housing. 2 . The movable tooth harmonic reducer according to claim 1 , wherein the inner side of the corresponding needle rollers on the casing is provided with a baffle plate that restricts the axial movement of the needle rollers, and the outer casing corresponds to the needle rollers. 3 . The outer side is provided with a retaining ring to limit the radial and axial movement of the needle roller. 3 . The movable tooth harmonic reducer according to claim 1 , wherein the center of the input shaft is provided with a keyway for accessing the power to be decelerated. 4 . 4 . The movable tooth harmonic reducer according to claim 1 , wherein the flexible wheel positioning portion is fixed on the inner ring end face of the cross bearing by means of bolts. 5 . 5 . The movable tooth harmonic reducer according to claim 1 , wherein the outer ring of the cross bearing is fixed on the end face of the casing by screws. 6 . 6 . The movable tooth harmonic reducer according to claim 1 , wherein the Z ₂ is 100, the Z ₁ is 98, a=21.92mm, b=21.4mm. 7 .

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