CN105020347A - Eccentric swing type planet gear device - Google Patents

Abstract

The invention provides an eccentric swing type planet gear device. The eccentric swing type planet gear device comprises an internally-toothed gear and an externally-toothed gear. The internally-toothed gear has the arc-shaped tooth form. The number of teeth of the externally-toothed gear is smaller than the number of teeth of the internally-toothed gear. The externally-toothed gear has the epitrochoid tooth form. By means of an eccentric crankshaft supporting swinging and rotating of the externally-toothed gear, the externally-threaded gear revolves in the internally-threaded gear. On the tooth top and at the tooth bottom of the externally-threaded gear, the tooth form of the gear is trimmed within the range from the tip of the theoretical tooth form obtained according to the epitrochoid theoretical trace to the positions, 60 degrees to 90 degrees away from the tip, on the two sides, and therefore the gear faces of the tooth bottom and the tooth top can be located inside the theoretical tooth form obtained according to the epitrochoid theoretical trace. By means of the eccentric swing type planet gear device, the design period can be greatly shortened, labor can be greatly reduced, expenses and evaluation time for sample manufacturing can be greatly reduced, and the application range of an epitrochoid tooth form speed reduction mechanism is greatly widened.

Description

A kind of eccentric oscillating-type planetary gear device

Technical field

The present invention relates to a kind of eccentric oscillating-type planetary gear device, undertaken in the eccentric oscillating-type planetary gear device of eccentric swing rotation at the external tooth gear engaged with internal-gear by eccentric crankshaft, the technology relevant to determining the castellated shape of its external tooth gear.

Background technique

At present, the number of teeth that eccentric oscillating-type planetary gear device contacts because of it and engages is many, and rigidity is high, is used in the articulation mechanism of articulated robot as speed reducer majority, the places such as the rotary drive mechanism of process equipment, the positioning means of processing accessory.

Internal-gear is made arc-shaped by this type of eccentric oscillating-type planetary gear device majority, and the external tooth shape of external tooth gear makes the shape meeting epitrochoid curve.

The trajectory calculation formula of the fixed point P of epitrochoid curve:

$\mathrm{\χ}=(\mathrm{rc}+\mathrm{rm})\cos \mathrm{\θ}-\mathrm{rd}\cos \left(\frac{\mathrm{rc}+\mathrm{rm}}{\mathrm{rm}}\mathrm{\θ}\right)$

$y=(\mathrm{rc}+\mathrm{rm})\sin \mathrm{\θ}-\mathrm{rd}\sin \left(\frac{\mathrm{rc}+\mathrm{rm}}{\mathrm{rm}}\mathrm{\θ}\right)$

Wherein, rc: basic circle radius; Rm: rolling circle radius; Rd: eccentric distance; θ: angle of revolution.

The external tooth gear of the reduction part of this type of eccentric oscillating-type planetary gear device maintains the fixed offset revolution of eccentric crankshaft, by engaging with internal-gear and revolve round the sun simultaneously, corresponding with the number of teeth of external tooth gear and internal-gear, the drawer at movable side in internal-gear and external tooth gear can slowly run relative to fixed side.

The defect of prior art comprises:

In this type of eccentric oscillating-type planetary gear device, according to theory calculate design external tooth gear castellated shape obtain epitrochoid shape time, the most senior general of intermeshing pressure angle at the bottom of the external tooth tooth of external tooth gear and near tooth top reaches 90 °, the pressure that external tooth gear face is subject to becomes large, the friction also corresponding increase of internal-gear and external tooth gear, causes transmission efficiency to reduce, generates heat, gear surface is damaged, produce the problems such as noise.

In addition, due in eccentric oscillating-type planetary gear device, most teeth engages simultaneously, and the processing of profile of tooth needs to reach very high dimensional accuracy, and very little size deviation all will cause gear to assemble difficulty, and becomes the reason of severe friction and generation noise.

In addition, strictly control to reduce gear backlash and engagement can be made to become very tight, not only easily cause fluctuation and the vibration of torque, also can cause during zero load and drive the problems such as torque increase and transmission efficiency reduction.

For avoiding the generation of problems, need correspondingly to repair gear, but become easy in order to the production and assembling making internal-gear, generally adopt the pin of circular shape or the internal-gear of circular shape, cause the shape of internal-gear to be fixed, can only repair the shape of external tooth gear.

But because the contact-ratio of gear is high, external tooth gear complex-shaped, calculate and determine that the pressure size etc. of the face of gear of hertz stress is divided, is occurred to the change of engaging position, the higher part of pressure angle, all need calculating and the rich experience and verifying based on complexity that basis is carried out.

Summary of the invention

The present invention proposes a kind of eccentric oscillating-type planetary gear device; it comprises arc toothed internal-gear; gear ratio internal-gear few, the external tooth gear that has epitrochoid profile of tooth; support that external tooth gear swings to rotate and the eccentric crankshaft making it revolve round the sun in internal-gear; on at the bottom of the tooth top of external tooth gear and tooth; at the tip of the theoretical profile of tooth obtained according to epitrochoid theory locus in the scope of 90 degree to 60 degree, both sides; the profile of tooth of x gear, makes at the bottom of tooth and the face of gear of tooth top is in the inner side of the theoretical profile of tooth that epitrochoid theory locus obtains.

The eccentric oscillating-type planetary gear device that the present invention proposes, the profile of tooth of external tooth gear forms the rolling circle center of the epitrochoid profile of tooth of this profile of tooth to the coefficient between the distance and rolling circle radius of fixed point by setting, and described coefficient setting obtained within the specific limits.

In the present invention, there is arc toothed internal-gear and fewer than the number of teeth of internal-gear and have the external tooth gear of epitrochoid profile of tooth, and have for making external tooth gear can revolve round the sun in internal-gear and in the eccentric oscillating-type planetary gear device of the pivotal eccentric crankshaft of support external tooth gear established, at the bottom of the tooth of external tooth gear and on tooth top, from the tip of the theoretical profile of tooth of epitrochoidal track in the scope of 90 degree ~ 60 degree, both sides, make inside face of gear is in by finishing.

In the present invention, set the coefficient that the distance (hereinafter referred to as eccentric distance) of the aforementioned rolling circle center becoming the epitrochoid profile of tooth of the profile of tooth of external tooth gear to fixed point is relevant to rolling circle radius, and by by foregoing coefficient setting within the specific limits, to determine the profile of tooth of external tooth gear.

As shown in Figure 2, in the present invention, repair at the bottom of jointing scope α 1 and tooth in scope α 2, only trim amount t2 relative theory tooth top shape S1, theoretical tooth Bottom Shape S2 at the bottom of jointing amount t1 and tooth are trimmed to the inside finishing tooth top shape K1, finishing tooth Bottom Shape K2.

Repair scope α 2 at the bottom of this jointing scope α 1, tooth and be set to 90 ° ~ 60 °, at the bottom of jointing amount t1, tooth, trim amount t2 is set to 0.01 ~ 0.02mm.

If by repairing scope α 2 and jointing amount t1 at the bottom of jointing scope α 1, tooth, trim amount t2 at the bottom of tooth is set to than above-mentioned little scope, absolute magnitude of its finishing diminishes, and still exists due to the scope at high pressure angle, reduces the effect of finishing.

On the contrary, if increase this finishing scope, the scope of theoretical profile of tooth can be made to narrow, transmission efficiency declines.

By this finishing, even if when requiring higher profile of tooth contact-ratio, also can avoid the engagement range under high pressure angle, while not lowering efficiency, suitable transmission effect can be obtained.

At present, namely allow to setting pressure angle, also need to be calculated or simulation at each point by the shape along external tooth gear, to be reacted in shape, and the present invention has the scope of finishing effect by the Range Representation of shape.

In addition, in order to the engagement range of well balanced external tooth gear a11 and internal-gear 12, offset rd is set to 2 times, and using this value divided by the value of rolling circle radius r m as cycloid coefficient T _f.

Cycloid coefficient T _fcalculating formula:

$T_f=2\×\frac{\mathrm{rd}}{\mathrm{rm}}$

Wherein, T _f: cycloid coefficient, rm: rolling circle radius; Rd: eccentric distance.

In the present invention, by by above-mentioned cycloid coefficient T _fbe set between 0.7 ~ 0.9, easily can set suitable external tooth gear a11 and the engagement range of internal-gear 12, ensure that transmission efficiency.

In Fig. 3, describe cycloid coefficient T _fbe set to profile of tooth when 0.4 (Fig. 3-1), 0.6 (Fig. 3-2), 0.8 (Fig. 3-3), 0.9 (Fig. 3-4) respectively.

As shown in Figure 3, when being located between 0.8 ~ 0.9 by this coefficient, the shape of suitable external tooth gear a11 can be obtained.Coefficient T _fless than normal, its contact-ratio can reduce, and can depart from from the engagement spacing point of internal-gear 12 and external tooth gear a11, and Sliding velocity increases, and frictional loss also increases thereupon, causes transmission efficiency to reduce.

External tooth gear b18 in accompanying drawing is also applicable to above statement.In the structure adopting multiple external tooth gear, all external tooth gears can adopt identical method for finishing to obtain suitable profile of tooth.

Beneficial effect of the present invention comprises:

The present invention can set at the bottom of the tooth of external tooth gear and the profile modification scope of tooth top and trim amount easy as can.In addition while reduction external tooth gear surface pressure, by with the coefficient representing eccentric distance and rolling circle relation, verify suitable external tooth gear shape, make without the need to just can easily draw suitable profile of tooth by complicated checking, reach the object that the eccentric oscillating-type planetary gear device that torque fluctuation and vibration can not occur can be provided.

By adopting the present invention, in the reducing gear requiring high contact-ratio, without the need to carrying out highly difficult parsing, suitable gear shape can be set easily.Its result, can avoid the engagement in elevated pressures angular region, and elevated pressures angle part is not pressurized.In addition, because cycloid coefficient easily confirms, high efficiency slowing effect can be obtained under suitable equilibrium configuration.

First calculated by theoretical formula and draw the shape of epitrochoid profile of tooth, afterwards can according to the present invention, setting tooth top and the finishing scope at the bottom of tooth and trim amount, and correspondingly repair to the inside, pressure angle is calculated respectively without the need to each engaging position at gear, or maximum value and the minimum value of tolerance is calculated by machining accuracy, repeatedly carry out profile modification.

In addition, by setting simple coefficient, be easy to the engagement of the gear after verifying design, without the need to coming verification efficiency and running-active status by repeatedly making various finishing sample.

In addition, the efficiency that can effectively prevent from face of gear pressure and frictional loss from increasing causing reduces, and can also prevent the generation of gear backlash.

With calculating and the experience that can only pass through complexity at present, and making sample could determine that suitable castellated shape is compared repeatedly, during adopting the present invention can shorten design significantly, labour, the expense of making sample and evaluation time, largely extend the using scope of epitrochoid profile of tooth reducing gear.

Accompanying drawing explanation

Fig. 1 is the schematic diagram that epitrochoid is formed.

Fig. 2 is the schematic diagram of finishing at the bottom of tooth top and tooth in the present invention.

Fig. 3 is cycloid coefficient T of the present invention _fasynchronous profile of tooth schematic diagram.

Fig. 4 is the sectional drawing applying speed reducer of the present invention.

Fig. 5 applies the schematic diagram that in speed reducer of the present invention, external tooth gear and internal-gear coordinate.

Fig. 6 is the schematic diagram applying external tooth gear finishing in speed reducer of the present invention.

Embodiment

In Fig. 1 to Fig. 6, rm-rolling circle radius, rc-basis circle radius, rd-eccentric distance, p-fixes a point, α 1-jointing scope, repairs scope at the bottom of α 2-tooth, t1-jointing amount, trim amount at the bottom of t2-tooth, the theoretical tooth top shape of S1-, K1-repairs tooth top shape, the theoretical tooth Bottom Shape of S2-, K2-repairs tooth Bottom Shape.

In Fig. 1 to Fig. 6,1-input shaft, 2-eccentric crankshaft, 3-sun gear, 4-passes on gear, 5-input side supporting body, 6-outlet side supporting body, 7-pillar, 8-bolt, 9-shell, 10-bearing, 11-external tooth gear a, 12-internal-gear, 13-groove a, 14-groove b, 15-bearing outer ring, 16-bearing inner race, 17-bearing b, 18-external tooth gear b, 19-sell (internal tooth).

As shown in Figure 2, in the present invention, repair at the bottom of jointing scope α 1 and tooth in scope α 2, only trim amount t2 relative theory tooth top shape S1, theoretical tooth Bottom Shape S2 at the bottom of jointing amount t1 and tooth are trimmed to the inside finishing tooth top shape K1, finishing tooth Bottom Shape K2.

Repair scope α 2 at the bottom of this jointing scope α 1, tooth and be set to 90 ° ~ 60 °, at the bottom of jointing amount t1, tooth, trim amount t2 is set to 0.01 ~ 0.02mm.

If by repairing scope α 2 and jointing amount t1 at the bottom of jointing scope α 1, tooth, trim amount t2 at the bottom of tooth is set to than above-mentioned little scope, absolute magnitude of its finishing diminishes, and still exists due to the scope at high pressure angle, reduces the effect of finishing.

On the contrary, if increase this finishing scope, the scope of theoretical profile of tooth can be made to narrow, transmission efficiency declines.

By this finishing, even if when requiring higher profile of tooth contact-ratio, also can avoiding the engagement range under high pressure angle, when not lowering efficiency, suitable transmission effect can be obtained.

At present, namely allow to setting pressure angle, also need to be calculated or simulation at each point by the shape along external tooth gear, to be reacted in shape, and the present invention has the scope of finishing effect by the Range Representation of shape.

In addition, in order to the engagement range of well balanced external tooth gear a11 and internal-gear 12, offset rd is set to 2 times, and using this value divided by the value of rolling circle radius r m as cycloid coefficient T _f.

Cycloid coefficient T _fcalculating formula:

$T_f=2\×\frac{\mathrm{rd}}{\mathrm{rm}}$

Wherein, T _f: cycloid coefficient, rm: rolling circle radius; Rd: eccentric distance.

In the present invention, by by above-mentioned cycloid coefficient T _fbe set between 0.7 ~ 0.9, easily can set suitable external tooth gear a11 and the engagement range of internal-gear 12, ensure that transmission efficiency.

In Fig. 3, describe cycloid coefficient T _fbe set to profile of tooth when 0.4 (Fig. 3-1), 0.6 (Fig. 3-2), 0.8 (Fig. 3-3), 0.9 (Fig. 3-4) respectively.

Known by Fig. 3-1 ~ 3-4, when being located between 0.8 ~ 0.9 by this coefficient, the shape of suitable external tooth gear a11 can be obtained.Coefficient T _fless than normal, its contact-ratio can reduce, and Sliding velocity increases, and frictional loss also increases thereupon, causes transmission efficiency to reduce.

As shown in Figure 5, the present invention proposes a kind of eccentric oscillating-type planetary gear device, it includes arc toothed internal-gear 12, fewer than the number of teeth of internal-gear, there is the external tooth gear a11 of epitrochoid profile of tooth, support that external tooth gear a11 swings rotate and make the eccentric crankshaft 2 that it revolves round the sun in internal-gear 12, on at the bottom of the tooth top of external tooth gear a11 and tooth, at the tip of the theoretical profile of tooth obtained according to epitrochoid theory locus within the scope of 90 degree ~ 60 degree, both sides, the profile of tooth of x gear, make at the bottom of tooth and the face of gear of tooth top is in the inner side of the theoretical profile of tooth that epitrochoid theory locus obtains.

The eccentric oscillating-type planetary gear device that the present invention proposes, the profile of tooth of external tooth gear forms the rolling circle center of the epitrochoid profile of tooth of this profile of tooth to the coefficient between the distance and rolling circle radius of fixed point by setting, and described coefficient setting obtained within the specific limits.In the gearing adopting multiple external tooth gear, all external tooth gears can adopt identical method for finishing.

In the present invention, Fig. 4 is for applying speed reducer of the present invention, and Fig. 5 is external tooth gear and internal-gear cooperation figure, Fig. 6 is external tooth gear finishing figure.

When input shaft 1 rotates, the sun gear 3 that input shaft 1 is established according to castellated shape, by engaging with driving gear 4, drives three eccentric crankshafts 2 underdrive simultaneously.Its result, the bearing b17 integrally mounted with every root eccentric crankshaft 2 also rotates simultaneously, connects in external tooth gear a11 and external tooth gear b18 and internal-gear 12 limit, and limit maintains the phase difference swing rotation of 120 degree respectively.Because internal-gear 12 and shell 9 are fixed all-in-one-piece state, when eccentric crankshaft 2 rotates, external tooth gear a11 and external tooth gear b18 also swings rotation, makes to move in turn with the engaging position of the pin 19 of the internal tooth as internal-gear 12.

Now, the number of teeth of the gear ratio internal-gear 12 of external tooth gear a11, external tooth gear b18 is less a little, by the movement of this engaging position, relative to the internal-gear 12 of stationary state, there is the phase migration with number of teeth certain degree in external tooth gear a11, external tooth gear b18.Therefore, eccentric crankshaft 2 is with in the much the same situation of its speed of autorotation, and around the revolution of input shaft 1 surrounding, the input side supporting body 5 supporting eccentric crankshaft 2 rotates under the speed suitable with revolution speed with outlet side supporting body 6.

Because input side supporting body 5 is connected by bolt 8 with outlet side supporting body 6, make input side supporting body 5 and outlet side supporting body 6 become unitary rotation, reach the object driving other machineries be connected on certain supporting body.

In addition, sun gear 3 directly can establish castellated shape on input shaft 1, also can establish corresponding castellated shape on other gears of input shaft 1 shape all-in-one-piece.

Fig. 5 is the mated condition of external tooth gear a11 and internal-gear 12, and Fig. 6 is the finishing state description of external tooth gear.

External tooth gear a11 shape is such as shown in Fig. 6, is set to 65 ° by repairing scope α 2 at the bottom of jointing scope α 1 and tooth, and at the bottom of jointing amount t1 and tooth, trim amount t2 is set to 0.02mm, for theoretical profile of tooth, repairs to the inside.

In addition, the engagement range of external tooth gear a11 and internal-gear 12 is: after offset rd is set to 2 times by this value divided by rolling circle radius r m, using this value as cycloid coefficient T _f, and by this cycloid coefficient T _fvalue is set to state when 0.8.

Claims (2)

1. an eccentric oscillating-type planetary gear device, it comprises arc toothed internal-gear,

Internal-gear described in gear ratio few, the external tooth gear that has epitrochoid profile of tooth,

Support that described external tooth gear swings to rotate, and the eccentric crankshaft that can revolve round the sun in described internal-gear,

It is characterized in that; on at the bottom of the tooth top of described external tooth gear and tooth; at the tip of the theoretical profile of tooth obtained according to epitrochoid theory locus in the scope of 90 degree to 60 degree, both sides; the profile of tooth of x gear, makes the face of gear at the bottom of described tooth top and tooth be in the inner side of the theoretical profile of tooth that epitrochoid theory locus obtains.

2. eccentric oscillating-type planetary gear device as claimed in claim 1, it is characterized in that, the profile of tooth of described external tooth gear forms the rolling circle center of the epitrochoid profile of tooth of this profile of tooth to the coefficient between the distance and described rolling circle radius of fixed point by setting, and described coefficient setting obtained within the specific limits.