JPH0133702B2 - - Google Patents

Description

[Detailed description of the invention] (a) Technical field This invention relates to a planetary gear system.

Planetary gears are used as speed reducers and speed increasers.

However, compared to a simple gear reducer, there are many meshing points, and the pressure at all meshing points is not necessarily equalized. On the contrary, at a certain meshing point, a force may be generated that exerts a reaction in the direction of rotation. For this reason, the planetary gear system was noisy and had unexpectedly poor power transmission efficiency.

(a) Pitch disk, ring type planetary gear device If the machining accuracy of the gears is increased, the pressure at each meshing point will be evenly distributed and the gears will rotate smoothly. However, gears, which are rigid bodies, cannot elastically deform and compensate for even slight errors, so uneven pressure tends to occur.

Even if the machining accuracy is increased, it will not be effective unless the gears can be controlled to an accuracy on the order of several microns.

Therefore, instead of increasing accuracy, it is expected that other means will be used to equalize the pressure between the gears.

One is the technical idea of attaching a disk or rollers equal to the pitch circle to the side of the planetary gear, and providing a disk or cylinder equal to the pitch circle to the side of the outer shell internal gear.

The pitch disc and pitch ring are in contact with each other. This is a rolling contact. Convey surface pressure.

Gears make contact with each other. conveys torque.
Does not convey surface pressure. For this reason, deep biting does not occur.

Deep meshing between gears caused noise and reduced transmission efficiency, so the pitch disc and pitch ring system can eliminate these drawbacks to some extent.

Although it is not a planetary gear, the specifications of U.S. Patent No. 3293928 (issued December 27, 1966) and U.S. Patent No. 3548673 (issued December 22, 1970) include pitch discs,
A device combining pitch ring gears is shown.

A planetary gear with a pitch disc and pitch roller is provided in Utility Model Publication No. 16918/1973.

Furthermore, Japanese Patent Publication No. 17111/1987 also provided a similar pitch disk type planetary gear.

(c) Planetary gears using elastic bodies To solve the drawbacks of planetary gears, it is possible to use elastic bodies.

At the same time, the meshing points interfere with each other and exert excessive pressure on other meshing points, so the forces are not equalized.

The planet gear meshes with the sun gear and the planet gear. The pressure at this point of engagement is equal. but,
There are 3 or 4 planetary gears. Although it is desirable that these pressures are all the same, they are not.

If the planetary gears are elastically deformed, the pressures will not be completely divided into equal parts, but will become closer to each other.

Utility Model Publication No. 44-25692 shows a friction planetary wheel instead of a gear, and the planetary wheel is made of rubber.
This is because force is transmitted using the frictional force of the rubber, so there is slippage and large torque cannot be transmitted.

(d) Intermediate ring system planetary gear In Utility Model Publication No. 35-17538 and Special Publication No. 36-22661, the planetary gear is made into a ring shape, and the planetary gear is
It is a combination of a planetary gear and a planetary shaft. There is a gap between the intermediate ring and the planetary gear ring, which allows the gear ring to move and accommodate misalignment of the meshing points.

Even if you do this, it will have no effect at all if the sun shaft, output shaft, etc. are strictly supported by bearings and cannot move in a direction perpendicular to the shaft.

The sun gear (input shaft) and carrier shaft (output shaft) are
Unless it can move in a direction perpendicular to the axis, an intermediate wheel is useless.

(e) Elasticity, Pitch disk system
This system combines the features of both the pitch disc system (announced on June 27, 1978).

This combines a thin elastic ring gear and a pitch disk.

(F) Disadvantages of conventional planetary gear systems A planetary gear system consists of a sun gear, a planet gear, a carrier that supports the planet gear, and an external internal gear.

There are three or four planetary gears. In addition to gear accuracy, strict requirements are also placed on the splitting accuracy of the planetary gear shaft in the carrier.

The planetary gear axes must be equidistant and at a central angle of 120° or 90° with respect to the center of the carrier.

When there are four planetary gear shafts, it is required that the shaft centers are exactly at the corners of a square, and that the center of the square coincides with the center of the carrier shaft hole.

However, the center of the carrier shaft hole and the center of the planetary gear shaft are not necessarily machined to be equidistant. If the distance is different, the transmitted torque between the planetary gear and the outer shell internal gear will be different, and the pressure will be uneven.

It was confirmed that uneven pressure was actually being applied. Perform the following destructive tests. Stops rotation of the outer shell internal gear and carrier. Apply strong torque only to the sun gear.

If the torque is increased, the planetary gear system will be destroyed.

In many cases, the planetary gears break. 2 out of 4
It is common for one or one of the three to break. Never before have all four or all three broken.

This means that unequal forces are applied to the planetary gear.

A sun gear shaft is fixed to the sun gear, and a carrier shaft is fixed to the carrier. Both become input and output shafts.

The planet axis is 3-fold symmetrical or 4-fold symmetrical with respect to the center of the carrier.
It must be in a rotationally symmetrical position, but there will always be some misalignment. It is desirable that there is little deviation. This is tentatively called the division accuracy of the planetary axis.

Also, when force is applied equally to all planetary gears, it is called "equal distribution." Equal distribution is the ideal state. If the division accuracy is high, the distribution will approach equal distribution. However, it is difficult to improve the division accuracy.

A planetary gear system that is far from equal distribution produces a lot of noise, is subject to severe wear, and has large transmission losses.

(G) Number of teeth and reduction ratio of planetary gears The number of teeth of the sun gear, planetary gear, and outer shell internal gear,
Let them be S, P, and I.

S+2P=I (1) It is.

The planetary gear is pivoted on the carrier. In the coordinate system fixed above the carrier, the angular velocities of the sun gear, planet gear, and outer shell internal gear are Ω′s,
If Ω′p and Ω′i, −SΩs′=PΩp′=IΩ′i (2).

If the angular velocity of the carrier is Ωc, the angular velocities Ωs, Ωp, and Ωi in the stationary system are Ωs = Ωs' + Ωc (3) Ωp = Ωp' + Ωc (4) Ωi = Ωi' + Ωc (5). Substituting (3) and (5) into equation (2) yields SΩs+IΩi=(S+I)Ωc (6). This is the basic formula of a planetary gear.

Usually, the outer shell internal gear is fixed. Ωi＝O (7) It is.

The reduction ratio R is defined by Ωs/Ωc.

R=Ωs/Ωc=S+I/S=2+2P/S (8). Since P is a positive value, the reduction ratio R of the planetary gear device is always twice or more.

The upper limit of R will be discussed next.

(h) Range of planetary gears and reduction ratios The number n of planetary gears must be 3 or more from the viewpoint of balance.

n is often 3 or 4. More than this is rarely used. However, considering the general n, consider here the possible range of the reduction ratio R.

As R becomes larger, the sun gear becomes smaller and the planetary gear becomes larger. This means that S is small and P is large.

When the number of planetary gears is n, the central angle θp of adjacent planetary shafts is given by θp=360°/n (9).

At the limit when the planetary gears become large, adjacent planetary gears come into contact. At this time, the distance between the sun axis center and the planet axis center is (S+P)/2, and the distance between the planet axis centers is a value obtained by multiplying P by the modulus m. In the limit, the following formula holds: 1/2(P+S)sinθp/2=P/2 (10).

From (8) to (10), the limit reduction ratio Rc is Rc=2/1-sin180/n (11) is given by

When n=3, Rc=14.9 When n=4, Rc=6.8 When n=5, Rc=4.8, etc. In reality, the tooth tip of the planetary gear protrudes from the pitch circle by one module, so P on the right side of equation (10) should be replaced with (P+2), and the limit reduction ratio Rc will also be smaller than the above value. .

(k) Structure of the Invention The planetary gear device of the present invention comprises: (1) a sun gear; (2) an appropriate number of planetary gears meshing with the sun gear; (3) an outer shell internal gear meshing with the sun gear; It consists of (4) a carrier that supports the planetary gear, (5) a planetary shaft that is inserted through the center of the planetary gear and supported by having both ends inserted into the planetary shaft hole of the carrier, and (6) the planetary gear is (7) The outer shell internal gear consists of an internal gear ring and an inner cylindrical portion on both sides of the internal gear ring, (8 ) The planet disk can roll in contact with the inner surface of the inner cylinder, (9) The planet shaft hole of the carrier is an elongated hole with a finite component in the radial direction, and the planet shaft can move within the planet shaft hole. , It is characterized by the fact that it is made as follows. The particularly novel point is in (9).

(J) Embodiment An example in which the present invention is applied to a pitch disc and pitch ring type planetary gear device will be described.

FIG. 1 is a front view of a planetary gear device according to a first embodiment. FIG. 2 is a sectional view taken in FIG. 1. FIG. 3 shows a rear view.

There are four planetary gears 2, . . . surrounding the central sun gear 1. Surrounding the planetary gears 2, . . . , there is one outer shell internal gear 3.

The carrier 4 consists of a main carrier disk 4a and a sub-carrier disk 4b.

The carrier 4 supports the planetary gears 2, . . . by means of a planetary shaft 5.

The planetary gear 2 is a combination of a planetary gear ring 7 and planetary discs 6, 6 sandwiching the planetary gear ring 7 from both sides. Here, the outer diameter of the planetary disks 6, 6 is equal to the pitch circle diameter. The planetary shaft 5 rotatably supports the planetary disks 6, 6.

The outer shell internal gear 3 consists of an internal gear ring 9 and inner cylindrical parts 8, 8 provided on both sides of the internal gear ring 9.

The internal gear ring 9 and the planetary gear ring 7 have substantially equal widths and mesh with each other.

The planetary disk 6 contacts the inner circumferential surface of the inner cylindrical portion 8 and rolls thereon. Therefore, the inner diameter of the inner cylindrical portion 8 is equal to the pitch circle diameter of the outer internal gear 3.

The main carrier disk 4a and the sub-carrier disk 4b are connected at four locations. A convex portion 10 and an insertion protrusion 11 are formed on the inner surface of the main carrier disk 4a. Correspondingly, a convex portion 12 and an insertion hole portion 13 are provided on the inner surface of the sub-carrier disk 4b. Insertion hole part 13
The insertion protrusion 11 is inserted into the hole and fixed by ultrasonic welding, adhesion, etc. This is the case with plastics.

If the carrier is made of aluminum, the same structure is used, but the tip of the insertion protrusion 11 is caulked to enlarge the diameter and fixed to the insertion hole 13.

If the carrier is made of metal, it may be joined with rivets.

A sun gear shaft hole 14 is bored in the sun gear 1.

A carrier shaft hole 15 is formed in the carrier 4. The input shaft and output shaft are inserted into these. A wide opening 17 is formed at the front of the sub-carrier disk 4b.

A characteristic feature of the present invention is that the planet shaft hole 16 of the carrier 4 is an elongated hole having a component in the radial direction.

Conventionally, the planetary shaft hole is just a hole, and the planetary shaft 5
was fixed for this.

In the present invention, the planetary shafts 5 can be moved in the radial direction. This is its characteristic.

FIG. 4 is a rear view showing the back side of the main carrier disk. FIG. 5 is a sectional view taken in FIG. 4.

The planet shaft hole 16 is a long hole in radius.
The width of the shaft hole 16 is equal to the diameter of the planetary shaft 5. The planetary shaft 5 can be set at any position in the radial direction.

It is assumed that when the planetary shaft 5 is at the innermost position, the shaft center is at point W. It is called the innermost point W.

It is assumed that when the planetary shaft 5 is at the outermost position, the shaft center is at point U. It is called the outermost point U.

Point W is the planetary shaft radius r from the innermost edge of the planetary shaft hole 16.
only the outer points. Point U is a point located inside the outermost edge of the planet shaft hole 16 by the planet shaft radius r.

Both ends of the planetary shaft 5 can be displaced between the line segments UW.

FIG. 6 is a rear view showing the back side of the sub-carrier disk. FIG. 7 is a sectional view taken in FIG. 6.

Since the position of the planetary shaft 5 is flexible, the same carrier 4 can be used as a carrier for planetary gear devices with different reduction ratios.

FIG. 8 shows a front view of a planetary gear system with a smaller reduction ratio using the same carrier. FIG. 9 is a sectional view taken in FIG.

The planetary axis 5 is at the outermost point U.

The sun gear 1 is large and the planet gears 2 are small. Therefore, the reduction ratio R is smaller than the examples shown in FIGS. 1-3.

In addition to this, a planetary gear device in which the planetary shaft 5 is at the innermost point W can also be made.

(S) Role of the planetary disk and the inner cylindrical portion In the present invention, since the planetary shaft hole 16 can move in the radial direction, the movement of the planetary shaft 5 cannot be stopped by the shaft hole 16.

If left as is, the planetary gear 2 will be strongly jammed into the outer internal gear. Therefore, there is a possibility that the rotation becomes heavy.

Also, since there is a clearance between the teeth, there is usually no contact in the radial direction.

If this continues, there is a risk that the planetary gear 2 will tilt and the planetary shaft 5 will tilt.

In order to prevent this, the planetary gear is provided with two planetary discs 6, 6, and the outer shell internal gear 3 is provided with inner cylindrical portions 8, 8. Then, both are brought into contact in the radial direction.

The planetary disk 6 is made to roll on the inner surface of the inner cylindrical part 8.

In this way, the planetary gear 2 and the planetary shaft 5 will not be tilted. It also prevents the gears from meshing strongly with each other.

It is sufficient that the planetary disk 6 and the inner cylindrical portion 8 can be in contact with each other, so they do not necessarily have to be a tight circle. Figures 1 to 9
In the example shown, these are equal to the pitch circle. In this case, the circumferential speeds of the rolling surfaces are equal.

In reality, the two are not always in contact.
Since clearance is provided, there is no problem even if the circumferential speed of the rolling surface is slightly different. The inventor already knows this.

If the module is m, the number of teeth of the planetary gear and the external internal gear are P and I, then the pitch circle diameter is
Pm, Im.

If the diameters of the planetary disk 6 and the inner cylindrical portion 8 are Dp and Di, -Dp+Di=-Pm+Im (12) is sufficient. This is the contact condition.

Regarding the size of the planetary disk and inner cylinder, (1) In the case of a pitch circle (Figures 1 to 9) Dp=Pm (13) Di=Im (14) (2) The planetary disk is larger than the pitch circle In the case Dp>Pm (15) Di>Im (16) In particular, there may be a case where the planetary disk is approximately equal to the tip circle and the inner cylindrical portion is approximately equal to the root circle. Assuming that the root circle is 1.25 modules smaller than the pitch circle, Dp (P + 2') m (17) Di (I + 2.5) m (18). 2' in formula (17) represents a value of 2 to 2.5. The difference from 2.5m is the clearance.

(3) When the planetary disk is smaller than the pitch circle Dp＜Pm (19) Di＜Im (20) What is interesting about this is that when the planetary disk is smaller than the pitch circle,
This is a case where the inner cylindrical portion is approximately equal to the tip circle of the outer shell internal gear. In this case, Dp(P-2.5)m (19)'Di(I-2')m(20)'.2' in formula (20) represents a value of 2 to 2.5. The difference between 2.5m and 2′m is the clearance.

(B) Example Regarding the case (2) described in the previous section, examples are shown in FIGS. 10 to 12.

The planetary discs 6, 6 are larger than the tip circle of the planetary gear 2.

The inner cylindrical portions 8, 8 are approximately equal to or larger than the root circle of the external internal gear.

In this way, the outer shell internal gear 3 can be manufactured from one member. As in the previous example, the internal gear ring 9 and the inner cylindrical portion 8 are not made of three members, but are made of one member.

This has two meanings.

One thing is that the outer shell internal gear 3 can be molded in a mold because the gear is higher than the inner cylindrical part.

Another thing is that it can be assembled.

Since the outer shell gear is higher than the inner cylindrical part, the planetary gear ring 7 can be inserted into the internal gear ring 9 as is, and the inner cylindrical part does not get in the way.

As described above, the structure shown in FIGS. 10 to 12 has the advantage that the number of parts is reduced, so that parts manufacturing and assembly costs can be reduced.

(S) Example This corresponds to case (3) mentioned in the previous section. Drawings are omitted.

When the diameter of the planetary disc 6 becomes approximately the same as the tooth root circle, the planetary gear 2 can be made as a single piece. The gear ring 7 and the discs 6, 6 are integrated.

On the contrary, the outer shell internal gear 3 cannot be integrated. The gear ring 9 and the inner cylindrical part 8 must be separable.

(c) Effect There are two notable effects.

(1) One is that a common carrier can be used even if the planetary gear units have different reduction ratios R.

In this case, it is not necessary to make many carriers, so the mold production cost can be reduced. Inventory management also becomes easier.

(2) The other is more fundamental. This means that the equality of forces is improved. This story takes place after a single planetary gear device has been completed.

Since the planet axes can move radially, the planet gears themselves can also move radially.

Considering one conventional planetary gear, the torque TS received from the sun gear 1 and the torque TI received from the outer shell internal gear 3 are as follows, excluding friction:
Always equal.

TS=TI (21) However, the radial forces (pressures) are not equal.
Force from sun gear FS, force from outer shell internal gear
If FI, then FS≠FI (22).

For example, if there are n planetary gears (3 or 4) and the angle they make with a certain reference plane is θi (i=1...n),
From the balance of forces, _o 〓 ⁱ⁼¹ {(FSi−FIi)a cosθi+(TSi +TIi)sinθi}=0 (23) _o 〓 ⁱ⁼¹ {(FSi−FIi)a sinθi+(TSi +TIi)cosθi}=0 (24). a is the pitch circle radius of the planetary gear (Pm/
2). Furthermore, from equation (21), TSi=TIi (25) holds. However, since (22) holds for each i, TSi (=TIi) is not equal for i=1,...,4. This means that equal distribution cannot be achieved.

In the present invention, since the planetary gear moves, FSi＝FIi (26) It is. The previous terms of equations (23) and (24) disappear.

When the number n of planetary gears is 3, from (23) and (24),
Obtain the exact formula TSi=TS ₂ = TS ₃ (27) TI ₁ = TI ₂ = TI ₃ (28). In other words, the total torque is the same.

When n is 4, the equations are insufficient, so it cannot be said that the total torques are equal, but it can be said that TS ₁ = TS ₃ (29) TS ₂ = TS ₄ (30). It is clear that this is close to equality. (29) and (30) also hold for TIi.

In the next section, the effect of (1) will be explained in more detail.

(G) Common carrier and reduction ratio In section (H), it was shown that when the number of planetary gears is 3, 4, or 5, the limit reduction ratio Rc becomes 14.9, 6.8, or 4.8. The lower limit of the reduction ratio is always 2.

For normalization, the pitch circle radius (Im/2) of the external internal gear is the distance OW between the center O and the innermost point W.
The value obtained by dividing the distance OU between the center O and the outermost point U, the shaft hole inner edge ratio w, and the shaft hole outer edge ratio u are defined.

w=OW/(Im/2) (31) u=OU/(Im/2) (32) It is.

The distance between the center of the planetary axis and the carrier center O is (S
+P)m/2, and the value obtained by dividing this by (Im/2) and normalizing it is set as x.

x=S+P/I (33). From equations (8) and (1), x=R/2(R-1) (34). From the definitions of u and w, w≦x≦u (35). Any reduction ratio R determined by (34) and (35) can be realized.

The lower limit of R is 2, but the upper limit Rc depends on the number n of planetary gears. It is given by (11). (11), (34)
From the formula, 1/1+sin180°/n≦x<1 (36). When n=3, the left term in (36) is 0.53, n
When =4, the left term of (36) is 0.58. Therefore, when n=3, w does not need to be less than 0.53. When n=4, w does not need to be less than 0.58.

In order to be able to use a carrier having an elongated hole in common for vehicles with different reduction ratios, the distance UW between the outermost point UW and the innermost point W of the elongated hole must be long to some extent.

P/I=R-1/2(R-1) (30'), but for R=3, 4, and 5, this value is 1/4,
1/3, 3/8.

Since a common carrier is used when the change in R is 1 or more, the range of P/I must be 1/12 or more, preferably 1/8 or more. In other words
The value obtained by dividing UW by the pitch radius of the external internal gear must be UW/Im/2≧1/12 (30″).

(T) Material (1) All may be made of metal (steel).

(2) The planetary shaft may be made of metal and everything else may be made of plastic (such as Diuracon).

(3) The planet shaft is made of steel, the carrier is aluminum die-cast, and the planet disk and sun gear are made of sintered alloy (Fe, Ni,
Zn, Cu) and the rest may be plastic.

(H) Inclination of the planetary shaft hole The planetary shaft hole 16 only needs to have a component in the radial direction, and does not necessarily have to be in the radial direction.

It may be a shaft hole having a constant inclination angle with respect to the radius. In other words, a shaft hole with a part of the spiral cut out may be used. FIG. 13 is a schematic back view of the auxiliary carrier disk 4b (protrusions etc. are omitted).

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of a planetary gear device according to an embodiment of the present invention. Figure 2 is a sectional view of Figure 1. Figure 3 is a partially cutaway rear view of the same item. Figure 4 is a back view of the main carrier plate. Figure 5 is a sectional view of Figure 4. Figure 6 is a back view of the sub-carrier board. Figure 7 is a sectional view of Figure 6. FIG. 8 is a partially cutaway front view showing an example in which the reduction ratio is reduced.
Figure 9 is a sectional view of Figure 8. FIG. 10 is a partially cutaway front view showing another embodiment. Figure 11 is a sectional view taken along line XI-XI in Figure 11. Figure 12 is a rear view. FIG. 13 is a back view of the auxiliary carrier plate showing an example in which the planetary shaft hole is tilted from the radial direction. DESCRIPTION OF SYMBOLS 1...Sun gear, 2...Planetary gear, 3...Outer shell internal gear, 4...Carrier, 4a...Main carrier disk, 4b...Sub-carrier disk, 5...Planetary shaft, 6...
... Planetary disk, 7 ... Planetary gear ring, 8 ... Inner cylindrical part, 9 ... Internal gear ring, 10 ... Convex part, 1
1... Insertion projection, 12... Convex portion, 13... Insertion hole, 14... Sun gear shaft hole, 15... Carrier shaft hole, 16... Planet shaft hole, O... Center of carrier,
W: Innermost point of the shaft hole, U: Outermost point of the shaft hole.

Claims (1)

[Scope of Claims] 1. A sun gear 1, three or more planetary gears 2 that mesh with the sun gear, and an outer shell internal gear 3 that meshes with the sun gear 1.
A carrier 4 that pivotally supports the planetary gear 2 and the planetary gear 2
The planetary gear 2 consists of a planetary gear ring 7 and a planetary circle sandwiching the planetary gear ring 7 from both sides. The outer shell internal gear 3 consists of an internal gear ring 9 and inner cylinders 8, 8 on both sides of the internal gear ring 9, and the planetary disks 6, 6 have inner cylinder parts 8, 8. The planet shaft hole 16 of the carrier 4 is an elongated hole closed at the outer and inner edges with a finite component in the radial direction. The distance between point W, which is outside by a radius of 5, and point U, which is inside by the radius of the planet shaft from the outermost edge of the planet shaft hole 16.
A planetary gear device characterized in that the value obtained by dividing WU by the pitch circle radius of the outer shell internal gear is 1/12 or more, and the planetary shaft 5 is configured to be movable in the planetary shaft hole 16. 2. The outer circumference of the planetary discs 6, 6 is equal to the pitch circle of the planetary gear 2, and the inner circumference of the inner cylindrical portions 8, 8 is equal to the pitch circle of the outer shell internal gear 3.
The planetary gear device described in . 3. The outer circumference of the planetary discs 6, 6 is larger than the pitch circle of the planetary gear 2, and the inner circumference of the inner cylindrical portions 8, 8 is larger than the pitch circle of the outer shell internal gear 3. Planetary gearbox. 4 The outer periphery of the planetary disks 6, 6 is 0 to 0.25 modules larger than the tip circle of the planetary gear 2, and the inner cylindrical portions 8, 8
The planetary gear device according to claim 3, wherein the inner circumference of the outer shell internal gear 3 is equal to the root circle of the outer shell internal gear 3. 5. The outer circumference of the planetary discs 6, 6 is smaller than the pitch circle of the planetary gear 2, and the inner circumference of the inner cylindrical portions 8, 8 is smaller than the pitch circle of the outer shell internal gear 3. planetary gear system. 6. A patent claim in which the outer periphery of the planetary disks 6, 6 is approximately equal to the root circle of the planetary gear 2, and the inner periphery of the inner cylindrical portions 8, 8 is 0 to 0.25 modules larger than the tip circle of the outer shell internal gear 3. The planetary gear device according to item 5. 7. The planetary gear device according to claim 1, wherein the planetary shaft 5 is a round bar, and the planetary shaft hole 16 is in the form of a long groove provided on the inner surface of the carrier 4. 8. The planetary gear device according to claim 1, wherein the planetary shaft hole 16 is a through hole, through which both ends of the planetary shaft 5 are provided, and a retaining protrusion is provided at each end. 9 Distance OW between the center O of the carrier and a point W outside the innermost edge of the planet shaft hole 16 by the radius of the planet shaft 5
The shaft hole inner edge ratio w divided by the pitch circle radius of the outer shell internal gear is w≧1/1+sin180°/n, where the number of planetary gears is n, and the center O of the carrier and the highest point of the planetary shaft hole 16 are Distance from point U that is inside the outer edge by the radius of planetary axis 5
The planetary gear device according to claim 1, wherein the shaft hole outer edge ratio u, which is calculated by dividing OU by the pitch circle radius of the outer shell internal gear, is 1 or less. 10. The planetary gear device according to claim 9, wherein the number n of planetary gears is 4, and the shaft hole inner edge ratio w is 0.58 or more. 11. The planetary gear device according to claim 9, wherein the number n of planetary gears is 3 and the shaft hole inner edge ratio w is 0.53 or more. 12 Claim 1 in which the sun gear 1, the planetary gear 2, the outer shell internal gear 3, and the carrier 4 are made of steel.
The planetary gear device according to any one of items 1 to 11. 13. The planetary gear device according to any one of claims 1 to 11, wherein the sun gear 1, the planetary gear 2, the outer shell internal gear 3, and the carrier 4 are made of plastic. 14. Claim 1, in which the sun gear 1 and the planetary disk 6 are made of sintered alloy, the carrier 4 is made of aluminum die-cast, and the internal gear ring 9 and the inner cylindrical parts 8, 8 are made of plastic. ~1st
The planetary gear device according to any one of Item 1. 15. Claims 1 to 1 in which the planetary shaft hole 16 overlaps one of the radii of the carrier 4.
The planetary gear device according to any one of Item 14. 16 The planetary shaft hole 16 is inclined with respect to the radius of the carrier 4.
The planetary gear device according to any one of Item 14.