JPS60252845A - Asymmetrical planetary gear mechanism - Google Patents

Abstract

PURPOSE:To prevent gears from strongly biting into each other and interfering with each other at their tooth tips to obtain a smooth decelerating action, and as well to facilitate the assembly of an asymmetrical planetary gear mechanism, by providing discs and cylindrical surfaces to a planetary gear and an outer shell inner tooth gear, respectively, so that they abut against both side of the gear section. CONSTITUTION:Discs 22, 23 are made abut against the side surfaces of a planetary gear ring 8. Further, an outer shell inner tooth gear is formed in its both side surfaces with cylindrical surfaces 26, 27 which may be made into contact with the discs. The diameters of these discs are not equal together on both left and right sides thereof such that one disc 23 of them has a diameter larger than that of the other gear 22. Further, the cylindrical surfaces of the outer shell inner tooth gear have also different diameters in accordance with the diameters of the discs. With this arrangement the attachment of gears may be easily made from one side of the outer shell inner tooth gear by utilizing the differences mentioned above, and it is possible to prevent a gear tip interferance and strong biting between gears.

Description

DETAILED DESCRIPTION OF THE INVENTION (G) Technical Field The present invention relates to a planetary gear device that has a wide range of uses as a speed reducer and a speed increaser.

(B) Prior art and its problems Since a planetary gear device has many meshing points between the sun gear and the planetary gear, and between the planetary gear and the outer shell internal gear, it is difficult to balance the forces at each meshing point at the same time. difficult.

Even if machining accuracy is increased, good results are not necessarily obtained.

If the gears mesh too deeply into each other, noise and vibration will occur, and energy will be lost.

In order to prevent excessive meshing, there are planetary gear units that have a pitch disk or a piddelic installed coaxially with the gear.

When a disk or ring with the same diameter as the pitch circle is attached to the side of the gear, radial force is transmitted to the disk or ring. Therefore, even if there is eccentricity of the sun gear shaft or positional error of the planetary shaft, the gears will not mesh excessively with each other.

For example, in the specification of U.S. Patent No. 8,293,928 (issued December 27, 1966), in a torque converter in which an external gear and an internal gear mesh, pitch circles are formed on both sides of both gears. A device is shown in which a disk portion and a ring portion of equal diameter are integrally formed with each gear.

Also, U.S. Patent No. 3%548.67CII (1970
(Published on December 22, 2013) The specification shows a flat wheel or bevel gear in which a friction wheel with a diameter equal to the pitch circle is fixedly integrated on one side of the gear. It was difficult to set the backlash of the gears at the meshing point, so in order to eliminate the problem of backlash, the friction wheels transmitted radial force to each other.

These inventions broadly relate to gears in general, in which a pitch disk or a pitcheric is provided coaxially with the gear.

An invention that applies such a composite gear to a planetary gear, % *
$4 Ah.

Utility Model Publication No. 80-16918 provides rollers and cylindrical surfaces with outer diameters and inner diameters equal to the respective pitch circles on both sides of the planetary gear and the outer shell internal gear that meshes with the planetary gear.

The roller rolls on a cylindrical surface. The radial pressure is
Transmitted by a cylindrical surface. The gears only transmit rotational force to each other, and excessive meshing does not occur. It was an excellent idea.

However, in this invention, the planetary gears and rollers are provided spaced apart from each other on one long planetary shaft. The planetary shaft is longer, and the casing is also longer in the axial direction. The entire device is bulky and heavy. This pushed up the manufacturing cost and made it difficult to use in some cases.

Some ideas have attempted to overcome the inherent difficulties of planetary gears by using a completely different approach than the configuration of providing a disk or ring that is equal to the pitch circle.

The planetary gears are made of a material with high elasticity, and the meshing misalignment is absorbed by the elastic deformation of the planetary gears.

For example, the invention of Utility Model Publication No. 44-25692 may be mentioned. This is not a gear, but a planetary roller, and the planetary roller is made of an elastic material such as rubber.

However, if the gear is made of a flexible elastic body, there will be slippage, so the transmitted torque will be suppressed to a low level. Since it expands and contracts repeatedly and there is friction loss, it also has the disadvantage of generating heat and being easily fatigued. Since it does not mesh with gears, it can only be used for light loads.

Furthermore, an eighth solution was proposed.

For example, Utility Publication No. 85-17588, Special Publication No. 86-22
It is No. 661.

This is different from directly combining a planetary gear and a planetary shaft, but by adding an intermediate shaft between them.

The intermediate shaft and the planetary gear (ring-shaped) can rotate with each other. There is sufficient clearance between the intermediate shaft and the planetary gear.

Due to the gap, the planetary gear ring can be displaced slightly relative to the axis in any direction. Therefore, the misalignment of the meshing points can be equalized. No need for pitch disk, pitcheric, etc.

Such a gap-type planetary gear device may still be insufficient in terms of equal distribution of force at the meshing points. This method is effective if the carrier supporting the sun gear and planet gears can move freely in the radial direction.

However, if the sun axis cannot move freely, this method will not be effective unless the backlash of the gear itself is large.

However, the inventor believes that such a gap type is the most effective for equalizing the meshing of a planetary gear.

As explained in detail in the previous section about the eight technical ideas, in order to solve the problem of simultaneous misalignment of the meshing points of planetary gears, we adopted (1) pitch disk, ring method, (2) elastic gear method, and (3) ) Gap method There were 08 different technical ideas.

(1) looks very attractive. If the pitch disk is placed coaxially with the planet gear, the rotation speed of the disk and the planet gear will be the same, so there should be no slippage between the disk and the circumferential surface of the pitch gear, and the gear should roll correctly. It is.

Among these, a planetary gear device that combines configurations (1) and (2) has been proposed. This is Special Publication No. 54-17111 (published on June 27, 1929).

The planetary gear has a thin ring shape so that it can be easily bent.

A ring gear is sandwiched from both sides by pitch disks having concentric stepped portions and an outer diameter equal to the pitch circle, and the planetary shaft is passed through the shaft holes of the two pitch disks.

In this invention, the gear is configured to bend locally at the root of the tooth. Planetary gears, which are subjected to strong torque, have their tooth bases bend more strongly, which reduces the torque.

The idea is that this equalizes the transmission torque of each planetary gear.

1. (This invention, however, uses a planetary gear ring.)
□ Since the gap between the discs is 0 and both are fixed,
It was not possible to combine the advantages of (3).

Moreover, the inventor knows that the bending of the root of the tooth, which is said to be the greatest advantage of this invention, actually almost never occurs.

Suppose that three or four planetary gears have different transmission torques. A planetary gear ring with a large amount of torque will flex significantly at the tooth root. Due to the deflection, the phase of this planetary gear is delayed and the torque is slightly reduced.

However, if the amount of deflection is different for each planetary gear,
The transmitted torque is different.

Then, the transmitted torque differs at the meshing point between the planetary gear and the sun gear. Therefore, the sun gear is subjected to non-uniform radial pressure. This will cause excessive meshing between the sun gear and the planet gear.

The present inventor has been involved in research, development, manufacture, and sales of planetary gear devices for many years. The various planetary gear devices described above were actually manufactured and examined. -According to the experience of the present inventor, the gap method (3) is considered to be the most effective for equally distributing force in a planetary gear system.

Therefore, the present inventor invented a planetary gear device that combines (1) and (3) (Japanese Patent Application No. 56-114824,
(Published on 58.2.1, 1982-17244).

It has already been explained why the elastic gear system is ineffective. It is said that elastic deformation occurs unevenly and equalizes the meshing force, but elastic deformation is proportional to the applied force according to Hooke's law. Elastic deformation occurs unevenly, which means that the meshing forces are uneven.

If the meshing forces are uneven, there will be differences in the strength of the meshing, and this will not mean that the misalignment has been alleviated.

Rather, it is preferable to provide sufficient backlash so that the transmitted torque is always the same.

Furthermore, the present inventor also has doubts about the pitch disk and pitcheric method (1).

Piddelic, if the disk were perfectly circular, the disk and ring would be in constant contact. However, piderick cannot be a perfect circle.

This is because there are processing errors. Therefore, the inner diameter of the pitch disk is made slightly larger than the pitch circle, and the outer diameter of the pitch disk is made slightly smaller than the pitch circle. In this way, during processing, tolerances are set so that the pitch disk and the ring do not come into close contact with each other and a gap is created.

In this case, the pitch disk on the outer shell internally geared vehicle side and the pitch disks on both sides of the planetary gear do not always come into contact with each other. In fact, there is a lot of time spent without contact.

In the case of contact, there is some kind of dimensional error, such as when the pitch disk is not a perfect circle but close to an ellipse and the planetary gear is located on the short side of the circle, or when the centrifugal force is significant and the pitch disk is not aligned with the pitch disk. For example, when someone is forced to do something.

If the planetary gear set is vertically placed instead of horizontally, and there is some play between the sun gear and its shaft, the weight of the carrier will cause the pitch disk of the planetary gear at the lowest point to become piddelic. may come into contact with.

However, normally the pitch disc and the pitcheric are often separated.

Therefore, the inventor considered that there is little need for the disk and ring to be in contact with each other in the pitch circle.

Rather, I came up with the idea that it would be better to have the disc and ring in contact at the tips and bottoms of the teeth.

If there is a pitch disk or pitcheric, the outer shell internal gear and
Since the planetary gear cannot be pulled out laterally, δ is required.

However, since it is a single module at the tip of the tooth, it is prone to wear due to contact with the disk and ring. Another drawback is that it cannot transmit the Nurastoka sufficiently.

Therefore, the present inventor invented a planetary gear device in which the outer diameter of the disks on both sides of the planetary gear is larger than the tooth tip circle, and the inner diameter of the cylindrical surfaces on both sides of the outer shell internal gear is larger than the tooth bottom circle. (Japanese Patent Application No. 1981-1981, Japanese Unexamined Patent Publication No. 58-94656.58.
6.4゛Published).

This device is a system in which the outer shell internal gear is made of one piece. This has the advantage of reducing the number of parts.

In this type of gear, the sun gear is integrated into the unit F and cannot be removed from there.

However, instead of inserting the tip of the input shaft into the sun gear, a gear may be cut into the tip of the input shaft and used as the sun gear. This use has always been possible with conventional planetary gears without discs.

However, for those with a series of planetary gears with discs, the sun gear cannot be inserted into the unit after it is manufactured.

Therefore, the present inventor invented an asymmetric planetary gear device in which only one side is provided with a disk having a diameter smaller than the root circle (
(Patent application 1982-143466, filed on 8I5, 1981)
.

However, since only one of the planetary gear and the outer shell internal gear has a transfer surface, it is still not sufficient to reduce the noise level.

2) Structure of the Invention In the present invention, disks are provided on both sides of the planetary gear and the external internal gear, but they are not the same, one has a larger tip circle and the other has a smaller tooth bottom circle. It is made asymmetrical so that

Regarding the planetary gear, one of the discs has an outer diameter smaller than the tooth root circle. This is because the sun gear can be inserted from this direction.

The other disc has an outer diameter larger than the tooth tip circle. This is because the cylindrical surface of the corresponding outer shell internal gear is wider than the root circle of the outer shell internal gear, and the outer shell internal gear can be molded as one piece.

The planetary gear device of the present invention includes: (1) the planetary gear has a (al') ring-shaped planetary gear ring; (b) a small disk portion with an outer diameter smaller than the bottom circle of the planetary gear; and the planetary gear ring. A first planetary disk having an inner cylindrical portion loosely fitted into the planetary gear ring and a first planetary disk having a shaft through hole; A second planetary disk having a hole, correspondingly, (2) an outer shell internal gear, a gear portion meshing with the planetary gear ring, and (bl) on one side thereof. (C) a small cylindrical surface that faces and contacts the small disk portion of the first planetary disk and has an inner diameter equal to or smaller than the tip circle of the external shell internal gear; (C) a large disk portion of the second planetary disk on the opposite side; and a large cylindrical surface having an inner diameter larger than the root circle of the outer shell internal gear.

The difference between the outer diameter of the small disc part of the planetary gear and the outer diameter of the tooth tip circle is 0 to 2.
It is modular.

The difference between the outer diameter of the large disc part of the planetary gear and the outer diameter of the tooth tip circle is O~2
It is a module.

The difference between the tip circle and root circle of the small cylindrical surface and the large cylindrical surface of the outer shell gear may also be about 0 to 2 modules.

(3) Examples An explanation will be given with reference to drawings showing examples.

FIG. 1 is a partially cutaway front view of a planetary gear device according to an embodiment of the present invention. FIG. 2 is a partially cutaway rear view, and FIG. 8 is a sectional view taken along the line ■-■ in FIG.

Although the planetary gear system has a sun gear in the center, the device of the invention allows the sun gear to be inserted later. Even without the sun gear, it is still a cohesive unit.

This is the aforementioned (Special Publication No. 54-17111,
8-17244, JP-A No. 58-94656).

These planetary gears have a space where the sun gear should fit,
The disk on the planetary gear side is slightly blocking it, making it impossible to insert the sun gear after the unit is assembled.

However, in the present invention, since the outer diameter of the disk portion on the side of the planetary gear is smaller than the diameter of the root circle, the sun gear will be replaced later. : For this reason, the state before the sun gear is inserted is shown here - L7. The six reef cars are not shown in Figure 1V.

In reality, it is convenient to cut a gear on the output shaft of the motor and use it as the sun gear instead of using the sun gear. This is because the number of members can be reduced by the number of sun gears.

The planetary gear device 1 of the present invention includes an appropriate number (four in this example) of planetary gears 2 that mesh with a central sun gear, and a planetary gear 2 that meshes with a central sun gear.
an outer shell internal gear 3 that surrounds and meshes with these, and a planetary gear 2
It consists of a carrier 4 which supports the rotationally symmetrical position.

The planetary shaft 5 rotatably supports the planetary gear 2 with respect to the carrier 4.

The planetary gear 2 is a loose combination of a planetary gear ring 8, which is a ring-shaped gear cut on the outer periphery, and asymmetrical first and second planetary discs 6.7.

The carrier 4 is a combination of a main carrier M4a and a sub-carrier disk 4b.

On the inner surface of the main carrier 4 plate 4a, there is a protrusion 1 at a rotationally symmetrical position.
0, and an insertion protrusion 11 is formed thereon.

A convex portion 12 is provided at a corresponding position on the inner surface of the sub-carrier plate 4b.
and an insertion hole 13 is provided therein.

Main carrier plate 4a to insertion hole 13 of sub carrier plate 4b
Insert the insertion protrusion 11 of both carriers (il14a,
4. Combine b. The carrier can be made of plastic or metal.

In the case of plastic, it may be further bonded with adhesive. In the case of plastic, or the insertion protrusion 11 is
It is also possible to make it protrude outside and perform ultrasonic welding.

In this example, both carrier plates 4a and 4b are made of aluminum die-cast. The tip of the insertion protrusion 11 is made to protrude from the flowering hole 13 and is fixed with a caulk 28.

Of course, the carrier plate can also be made of iron. In this case, both carrier plates are welded through a connecting rod, or
It is fixed by caulking with rivets.

The center of the main carrier disk 4a is raised outwards.

A central raised portion 14 is formed. A carrier shaft hole 15 is provided at this center. Splines, hascellations, etc. are suitable for this purpose. Output shaft (when used as a reducer)
is attached to the carrier shaft hole 15.

The carrier plates 4a, 4b have planetary shaft fixing holes 16.16 at intermediate positions of the convex portions 10.12, into which the planetary shafts 5 are inserted.
0 Both ends are inserted and fixed.

There is an opening 17 in the center of the sub-carrier disk 4b, through which a sun gear or a motor shaft having a sun gear cut at the tip can be inserted.

The pitch circle 18 of the planetary gear 2 is shown by a dashed line.

The root circle 19 is much smaller than this. In FIG. 8 and FIG. 4, the boundary with the area where the halachin indicating the cross section of the gear is drawn is the root circle. This is typically 1.25 modules smaller in radius than the pitch circle.

The tip circle 20 is a semicircle compared to the pitch circle, and is usually larger than the pitch circle.

FIG. 4 is an enlarged sectional view of only the vicinity of the meshing portion between the planetary gear 2 and the outer shell internal gear 3.

The planetary gear 2 is a combination of three members. These are a geared planetary gear ring 8, and a first planetary disk 6 and a second planetary disk 7 that support it from left and right and are rotatably supported by the planetary shaft 5.

5 and 6 are perspective views of the first and second planetary discs 6.7.

The first planetary disk 6 consists of a small disk portion 22 having an outer diameter smaller than the tooth root circle 19 of the planetary gear, and an inner cylindrical portion 21. The inner cylindrical portion 21 is loosely fitted into the planetary gear ring 8 and supports it. The clearance of this space is 0.18 to 0.82 mm in diameter in this example.

The second planetary disk 7 consists of a large disk portion 23 having an outer diameter larger than the addendum circle 20 of the planetary gear, and an inner cylindrical portion 21 . This inner cylindrical portion 21 has the same function as any other portion.

The planetary discs 6.7 have different dimensions of the disc part, one having an outer diameter of less than the root circle and the other having an outer diameter of more than the tip circle.
The rest is the same, and both have a shaft through hole 1' 24 through which the planetary shaft 5 is inserted.

In this example, the clearance between the shaft through hole 24 and the planetary shaft 5 is as follows.
It is 0.05 to 0.118n.

The outer shell internal gear 3 has an eight-stage configuration corresponding to the three different structures of the planetary gears, but if it is made of plastic, it can be molded as one piece.

A gear portion 25 having a gear is located in the middle, and this meshes with the planetary gear ring 8. It can be said that meshing takes place effectively on the pitch circle 18.

Cylindrical surfaces 26.21 on the left and right sides of the gear portion 25 make rolling contact with the disk 6.7 of the planetary gear 2 near the tip circle and the root circle.
It becomes.

The small cylindrical portion 26 is an inner cylindrical surface that faces and contacts the small disk portion 22 of the first planetary disk 6 . It has an inner diameter less than the tip circle.

As the dimensional tolerance of this contact surface, for example, -0,09 to +0
．． 2 penalties.

The large cylindrical surface 27 on the opposite side is the large disk portion 2 of the second planetary disk 7.
This is an inner cylindrical surface that faces and contacts 3. It has an inner diameter larger than the root circle. As the dimensional tolerance of this contact surface, for example, -0,
09 to +0.2ff.

Here, when the dimensional tolerance is negative, it means that it actually happens, and the center of the disk 6.7 is at the planetary axis 5.
The center of , and the algebraic sum of dimensional tolerances when they coincide.

The clearance between the disk 6.7 and the planetary shaft 5 is 0.05f.
Since it is more than fll+, the total in the diameter direction is 0.1111
Can move in and out. For this reason, the disk 6.7 and the cylindrical surface 26.
Even if the tolerance of the rolling contact surface of 27 is -0.09ff,
There is no such thing as stopping movement.

Other shapes of the outer shell internal gear 3 are arbitrary.

In this example, depressions 32 and 33 are provided on the side where the input shaft is inserted, and a rotation stopper groove 31 is further provided on the outer periphery. These are intended to be fitted into a suitable casing and fixed by rotation.

Instead of being asymmetrical in the front-rear direction as in this example, it may be symmetrical like a normal planetary gear system.

φ) Effects (1) In the meshing between the planetary gear and the external internal gear, discs and cylindrical surfaces that come into rolling contact are provided on both sides of the gear part, which prevents loose meshing between the gears and tooth tips. Interference can be prevented.

(2) Since tooth tip interference is suppressed, noise is reduced and power transmission efficiency is improved.

(3) The disk into which the input shaft is inserted has an outer diameter that is less than the toothed circle, so the input shaft carved with a sun gear can be inserted from here.

If the teeth are cut directly on the tip of the motor shaft or other input shaft, one sun gear can be omitted.

(4) The outer shell internal gear can be molded as a single piece when subjected to blastic injection molding. This is because one side of the gear portion 25 has a large cylindrical surface 27 with a large inner diameter and a tooth bottom circle, and is shaped to be able to be removed from the mold.

In the case of the pitch disc type, the outer shell internal gear has three members, but the number of parts is reduced compared to this.

(To) Material (11 The planetary gear ring 8 may be made of either plastic or metal.

(2) The planetary disks 6.7 may be made of plastic, sintered alloy, or steel plate.

(3) The carrier may be plastic, sintered alloy, steel plate,
Aluminum die-casting, etc.

(4) The outer shell internal gear is made of plastic or aluminum die-casting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway front view of the planetary gear device of the present invention. Figure 2 is a partially cutaway rear view of the same item. FIG. 3 is a sectional view taken along the line ■-■ in FIG. FIG. 4 is an enlarged sectional view of the meshing portion of the planetary gear and the external internal gear. FIG. 5 is a perspective view of the first planetary disk. FIG. 6 is a perspective view of the second planetary disk. 1・・・・・・・・・Planetary gear device “′) 2・・・・・・・・・Planetary gear 3・・・・・・
......Outer shell internal gear 4...Carrier 4a...Main carrier plate 4b...
......Sub-carrier disk 5......Planet shaft 6...First planetary disk 7... Second planetary disc 8... Planetary gear ring 10...
...Convex portion 11...Pass-in protrusion 12...Convex portion 13...Pass-hole 14. ...... Central raised part 15 ...... Carrier shaft hole 16 ... ... Planet shaft stopper hole 17 ...
・・・・Opening 18・・・・・・・・・・Pitch circle 19・・・・・・・・・・Bottom circle 20・・・・・・・・・・Tip circle 21・・・・......Inner cylindrical section 22...Small disk section 23...Large disk section 24...・・Shaft through hole 25 ・・・・・Gear part 26 ・・・・・・Small cylindrical surface 27 ・・・・Large cylindrical surface Kyo HidePatent applicant Matex Co., Ltd.

Claims (1)

[Claims] It consists of an appropriate number of planetary gears 2 that mesh with the sun gear, an outer shell internal gear 3 that meshes with these, and a carrier 4 that supports the planetary gears 2 with a planetary shaft 5 and is rotatably provided. In the planetary gear device, the planetary gear 2 includes a ring-shaped planetary gear ring 8, a small circular plate portion 22 having an outer diameter smaller than the tooth bottom circle of the planetary gear, and an inner cylindrical portion 21 that is loosely fitted into the planetary gear ring 8.
and a first planetary disk 6 having a shaft through hole 24, a large disk portion 23 having a larger outer diameter than the tooth tip circle, an inner cylindrical portion 21 loosely fitted into the planetary gear ring 8, and a shaft through hole 24. The outer shell internal gear 3 is connected to the second planetary disk 7, and has a gear portion 25 that meshes with the planetary gear ring 8, and a gear portion 25 that faces and contacts the small disk portion 22 of the first planetary disk 6 on one side thereof. The side opposite to the small cylindrical surface 26 having an inner diameter equal to or less than the tip circle of the internal shell gear is in opposing contact with the large disk portion 23 of the second planetary disc T, and has an inner diameter equal to or greater than the root circle of the outer shell internal gear. An asymmetric planetary gear device characterized by comprising a large cylindrical surface 27 having a large cylindrical surface 27.