JPS61136041A - Speed reduction unit using trochoid tooth gear - Google Patents

Abstract

PURPOSE:To enhance the mechanical efficiency of a speed reduction unit, by holding rollers for meshing an internal gear with an external gear such that they may revolve and parallelly move to reduce a slip on a meshing surface. CONSTITUTION:Rollers 25, 28 are disposed between a stationary internal gear 12 and external teeth 23 n a swingable external gear 22 and between an internal gear 18 on an output shaft 17 and external teeth 24 on the swingable external gear 22, respectively. The number of these rollers 25, 26 is equal to the number of recesses between teeth 13, 19 of the recesses. This holding may be established in the respective combination of flat washer type holder 26, 29 having their inner diameter side sections bent at right angle and ring-like holders 27, 30, thereby it is possible to rotate and parallelly move rollers 25, 26 within the recess.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reduction gear using trochoidal tooth profiles.

[Conventional technology]

Conventionally, as a reduction gear applying an internal planetary gear mechanism, a cyclo reduction gear using a trochoidal tooth profile has been proposed, for example, in Japanese Patent Application Laid-open No. 71459/1983.

These speed reducers have a large reduction ratio and can transmit large torque despite being relatively compact.

The reducer described in item 1 stores a pin in the recess of the internal gear, meshes the external gear with the internal gear via this pin, and outputs differential rotation based on the difference in the number of teeth between these gears. The shaft is to be taken out.

[Problem that the invention seeks to solve]

By the way, in a reducer like the one described above, large slippage occurs when the external gear and pin engage, and this friction 41]
This poses a problem in that the machine becomes less efficient.

Actually, in order to convert this sliding friction into rolling friction, O
Although some pins have rotatable pins, it is difficult to miniaturize them due to their structure, for example, it is difficult to reduce the outer diameter to 100 m4 or less.

This invention was developed in order to solve the problems mentioned in item 1, and has less slippage on the tooth surface and a durability f1.
The purpose of the present invention is to provide a reduction gear that is small and has high mechanical efficiency as well as excellent mechanical efficiency.

[Means for solving problems]

In order to solve the problems mentioned in item 1, this invention
Hypotrochoid internal gear with two teeth, N-2
It is composed of an epitrochoid external gear having two teeth, and rollers corresponding to the number of recesses that are housed in the recesses of the internal gear or the external gear and held by a cage so as to be able to rotate and move in parallel. The internal gear and external gear are rolled so that they mesh with each other via rollers.

[For production]

The internal gear and the external gear mesh through a roller that fits in the recess of the internal gear or the external gear, and by eccentrically rotating one gear, the other tooth rlj is rotated at a reduced speed by the difference in the number of teeth, The decelerated rotation is taken out to the output shaft.

Since the rollers are caged to allow rotation and translation within the recesses of the gear, the rollers have reduced slippage in all phases, increasing mechanical efficiency.

〔Example〕

Hereinafter, embodiments of the present invention will be explained based on the attached documents.

Fig. 1 shows the basic structure of the internal planetary gear mechanism used in the reduction gear O of this invention. An external gear 2 having a tooth profile, a third tooth profile recess of the internal gear 1, and rollers 4 as many as the number of recesses 3 held by a cage so as to be able to rotate and move in parallel in the vicinity of the recess 3. The internal gear 1 and the external gear 2 mesh with each other via a roller 4, and the roller 4 is held in a recess 3.
There is no possibility that it will move over a convex part to the next concave part.

In the illustrated case, the internal gear 1 has 24 teeth and the number of rollers 4 is also 24, while the external gear 2 has 22 teeth, which is two fewer than these.

The center of the internal gear 1 is eccentric to Oh1, the center of the external gear 2 is eccentric to Oe, and the rollers 4 are black 1.2.3.4 and 22.23 restrained by the recesses 3.5 of both gears 1.2. .24 is Op
are arranged at equal pitches and equal PCD around
The roller 4 of No. 1 is not restrained, is located near the recess 3 of the internal gear 1, and is not involved in the torque load.

In this invention, each of the rollers 4 is arranged at an equal pitch and an equal pitch.
A cage restraining the CD is not required and this is illustrated in FIGS. 2 and 3.

Figure 2 shows the curvature of the contact point of the roller 4 with the external gear 2 at each phase. The curvature of the external gear is the gate.

FIG. 3 shows the curvature of the contact point of the roller 4 with the internal gear 1 at each phase, and from FIG.
At 60 degrees, the gate portion of the internal gear 1 and the roller 4 come into contact.

As a result of the above, the roller 4 has a phase of O~47° and a phase of 313~36°.
At 0°, the roller 4 is surrounded by the recess 3 of the internal gear 1 and the recess 5 of the external gear 2, and the position of the roller 4 is fixed, so there is no need for a cage to restrain the rollers at a constant pitch and constant PCD. Become.

In addition, if the curves of the internal gear 1 and the external gear 2 are made into parallel hypotrochoid and epitrochoid curves as per the theory,
Each tooth tip becomes high and the rollers A5 to 21 are sandwiched between the tooth tips and may be involved in torque load. Therefore, it is necessary to correct the convex portions of the tooth tips of the internal gear 1 and the external gear 2 to be lower. is preferred.

Next, it will be explained that the meshing friction of the tooth surfaces is reduced by not restricting the rollers 4 to a uniform pitch.

Figure 4 shows the theoretical value of the sliding speed at the meshing angle between the roller and the trochoid gear.

If the sliding speed of the 71 epitrochoid gear is expressed as Ve when it is assumed that the roller cannot rotate, the difference Vr will be expressed as the actual slip.

The horizontal axis in FIG. 4 indicates the phase of the roller, and the vertical axis is made dimensionless by dividing the sliding speed by the moving speed of the roller.

As is clear from Figure 4, if the roller is made rotatable,
It can be seen that the slippage decreases in all phases.

However, in other words, slipping occurs in all phases of the roller, and in the phase of about 50 to 1800, the roller touches the convex part of the tooth tip of the hypotrochoid gear, as described in . Since the rollers are surrounded by the convex parts of the epitrochoid gear teeth, if the rollers are restrained at a constant pitch by the cage, a large force will be applied to the cage, and if the rollers are not restrained by the cage at a constant pitch, the rollers will Since it deviates from the equal pitch point, it becomes impossible to sharpen when torque is applied.

Figure 5 shows the first part of the reducer using the internal planetary gear mechanism.
An example is shown.

The internal gear 12 fixed to the case 11 with bolts has 24
An input shaft 15 is carved with a tooth profile 13 in the form of a noibotrochoid and is supported by an internal gear 12 with a bearing 14;
An output shaft 17 supported by the case 11 via a bearing 16 is arranged coaxially.

An internal gear 18 is provided at the inner end of the case 11 of the output shaft 17 , and a hypotrochoidal tooth profile 19 having 20 teeth is carved into this gear 18 , and the portion of the input shaft 15 located inside the case 11 is provided with an internal gear 18 . A swinging external gear 22 is rotatably attached to an eccentric portion 20 provided in the shaft via a bearing 21.

On the outer peripheral surface of the external oscillating gear 22 facing the internal gear 12, there is an epitrochoid-shaped tooth profile 23 having 22 teeth, and on the outer peripheral surface of the output shaft 17 facing the internal gear 18, there are 18 teeth. An epitrochoidal tooth profile 24 with teeth is carved.

Between the tooth profile 13 of the fixed internal gear 12 and the tooth profile 23 of the oscillating external gear 22, 24 rollers 25 that fit in each recess of the tooth profile 13 are arranged, and the rollers 25 are attached to the fixed internal gear 12. It is held in the vicinity of the concave portion of the tooth profile 13 by retainers 26 and 27 so as to be rotatable and movable.

One retainer 26 that holds the roller 25 is formed in the shape of a flat washer with the inner diameter side bent at right angles, and is fixed to the fixed internal gear 12 with bolts.
7 is formed into a ring shape and is press-fitted inside the fixed internal gear 12.

Furthermore, 20 rollers 28 that fit within the recesses of the tooth profile 19 are disposed between the tooth profile 19 of the internal gear 18 of the output shaft 17 and the tooth profile 24 of the oscillating external gear 22.
8 is also held by two types of retainers 29 and 30 similar to those described above so that it can rotate and swing freely near the recess.

In the above reduction gear, when the input shaft 15 is rotated, the tooth profile 23 of the oscillating external gear 22 attached to the eccentric part 20 swings along the tooth profile 13 of the fixed internal gear 12, and the tooth profile 13 and
Rotation occurs by the difference in the number of teeth of 3.

The tooth profile 24 of the oscillating external gear 22 corresponds to the internal gear 1 of the output shaft 17.
The output shaft 17 is oscillated along the tooth profile 19 of 8, and rotation is applied to the output shaft 17 by the difference in the number of teeth 24 from the tooth profile 1 and the amount of rotation of the oscillating external gear 22.

The reduction ratio of the above speed reducer is the same as that of a general two-stage internal planetary gear mechanism, and a reduction ratio of 1 24 x 1.8 1 / = 1 - = / is obtained, and R22 x 2
0 55 Ru〇Next, in the second example of the reducer shown in FIG. The 24 rollers 44 that fit into the recesses are held elastically in the tooth-shaped recesses by elastomers 45 and 46, such as rubber, provided in the case 41.

Eccentric part 4B provided on the input shaft 47 with a phase shift of 1800
, 49, the oscillating external gears 50 and 51 are respectively mounted on bearings 52.5.
An epitrochoidal tooth profile 52 with 22 teeth is carved into both gears 50 and 51, and the output shaft 54 meshes with the internal gear 42 at a phase of 180° via a roller 44. It is connected to both oscillating external gears 50 and 51 by a sliding bearing 55 and an inner pin 56.

The action of this reducer is similar to that of a general cyclo reducer, and the rotation component of the oscillating external gear 50, 51 is transmitted to the inner pin 56 via the sliding bearing 55 by a constant velocity internal gear mechanism.
This is what is taken out as output.

FIG. 7 shows the meshing state of the roller 44 and the trochoidal gear in the speed reducer.

In Fig. 7, two oscillating external gears 50 and 51 with epitrochoid tooth profiles are used with a 180° phase shift. Since the gear 50 and the other external gear 51 mesh with the rollers 44 of the oscillating external gears and the rollers 10 to 16, the only rollers 44 that do not apply torque are the oscillating external gears and the rollers 17 to 21. The number of meshes increases and the allowable torque increases.

In each example, the number of rollers is matched to the number of teeth of the epitrochoid internal gear, but depending on the case, the number of rollers may be matched to the number of teeth of the epitrochoid. It is preferable to install it on the smaller number of gears.

〔effect〕

As described above, according to the present invention, the above-described configuration has the following effects.

(1) A roller that fits into the recess of a hypotrochoid internal gear or an epitrochoid external gear is held by a cage so that it can rotate and move in parallel, and the internal gear and external gear are meshed via the roller. Therefore, since the rollers rotate freely, most of the slippage of the meshing portion can be eliminated, and mechanical efficiency can be improved.

(Ill) Since there is no need for a retainer to restrain the rollers at a constant pitch and constant POD, the structure becomes extremely simple and the reduction gear can be made smaller.

(m) By lowering the protrusions on the tip of the hypotrochoidal tooth profile or epitrochoidal tooth profile and limiting the area that engages with the roller within the concave part, the protrusions where surface pressure is high can be used to load torque. The load capacity increases.

(When the meshing ratio between the M roller and the tooth profile decreases, the order of the indeterminate state decreases, and local overload due to machining errors occurs. Only the concave shape remains.

Processing time can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the basic structure of the internal planetary gear mechanism used in the reduction gear of the present invention, Fig. 2 is a graph showing the curvature of the contact point with the external tooth at each phase of the roller, and Fig. 3 is a graph showing the curvature of the contact point with the external tooth at each phase of the roller. A graph showing the curvature of the point of contact with the internal tooth at each phase of the roller, FIG. 4 is a graph showing the theoretical value of the sliding speed when the roller and tooth profile mesh, and FIG. 5 is the first reduction gear according to the present invention. FIG. 6 is a vertical cross-sectional view showing the second example, and FIG. 7 is a plan view showing the relationship between gears and rollers in the second example. DESCRIPTION OF SYMBOLS 1... Internal gear, 2... External gear, 3.5... Recess, 4... Roller, 11... Case, 13... Tooth profile, 14... Bearing, 15... ...Input shaft, 16...Bearing, 17...Output shaft, 18...Internal gear, 19...
・Tooth profile, 20... Eccentric part, 21... Bearing, 22...
- Oscillating external gear, 23.24... Tooth profile, 25... Roller, 26.27... Cage, 28... Roller, 2
9.30...Cage, 41...Case, 42...
Internal gear, 43... Tooth profile, 44... Roller, 45.
46... Elastomer, 47... Input shaft, 48.4
9... Eccentric part, 50.51... Oscillating external gear, 52
．． 53...Bearing, 54...Output shaft, 55...Sliding bearing, 56...Inner pin same agent sickle 1) Written by NikasuQ Shibabo

Claims (4)

[Claims] (1) A hypotrochoid-shaped internal gear with N teeth, an epitrochoid-shaped external gear with N-2 teeth, and a cage that fits in the recess of the internal gear or external gear and allows rotation and parallelism. A reduction gear that uses a trochoidal tooth profile in which an internal gear and an external gear mesh with each other via the rollers, and are configured with rollers that are held so as to be movable and have the same number of recesses. (2) A speed reducer using a trochoidal tooth profile according to claim 1, wherein the cage is made of an elastic material that presses the roller against the recess to reduce vibration. (3) A speed reducer using a trochoid tooth profile according to claim 1, wherein the shape of the convex portion of the tooth surface of the hypotrochoid internal gear or epitrochoid external gear is lower than the theoretical trochoid locus. (4) The invention according to claim 1, wherein either the hypotrochoidal internal gear or the epitrochoidal external gear is attached to an eccentric cam for eccentric rotation to constitute an internal planetary gear mechanism. Reduction gear using trochoid tooth profile.