JP2930933B1 - Grease self-holding planetary gear set - Google Patents

Abstract

To provide a function of holding and confining grease in a space surrounded by a carrier disk in a planetary gear device having an integrated asymmetrical planetary gear and an asymmetrical internal gear. SOLUTION: The outer periphery of a main carrier disk is made wider than the pitch circle of an internal gear, and the outer periphery of the main carrier disk is radially opposed to a large cylindrical portion of an outer shell internal gear through a narrow gap. The sub-carrier plate is in sliding contact with the side surface of the small shell portion of the outer shell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear device capable of retaining grease therein. In particular, the present invention relates to a structure of a planetary gear device capable of storing grease permanently between carriers and maintaining a long lubricating performance. The planetary gear set is usually housed in a casing and used as a speed reducer. The casing is filled with grease or lubricating oil to smooth the rotation of the planetary gear set. However, this requires filling the casing with grease or oil. The casing must be sealed to prevent leakage of grease and oil. The casing is not necessarily sealed and it is uneconomical to fill the casing with lubricant. Therefore, it would be more convenient if the grease could be self-maintained with only the planetary gear set.

[0002] A "planetary gear" is an intermediate gear provided with three or four gears. "Planetary gear set" means the entire set. Planetary gears and planetary gearing are used so distinctively. Hereafter, the planetary gears and the planetary gear set must not be confused. The four elements of the planetary gear set are the sun gear, the planetary gear, the carrier, and the external gear of the outer shell.

[0003]

2. Description of the Related Art A planetary gear device has a sun gear at the center, three or four planetary gears surrounding the sun gear, and an external gear internally surrounding the sun gear. Disc-shaped carriers as well as gears are components. The plurality of planet gears are rotatably supported by the carrier. The rotation of the sun gear rotates the planetary gear and the rotation of the planetary gear rotates the carrier. The rotation of the carrier is slow because the number of teeth of the internal gear is much larger than the number of teeth of the sun gear. That is, the rotation of the sun gear is reduced and transmitted to the carrier. It is widely used as a speed reducer with sun gear input and carrier output.

In an ordinary planetary gear device, a sun gear, a planetary gear, and an internal gear (an internal gear of an outer shell) are simple gears, and a gear is formed over the entire width of the gear.
Since the cross-section in the axial direction is invariable, it is impossible to prevent the planetary gear or the sun gear from being displaced in the axial direction with respect to the internal gear (outer shell internal gear) by the action of the gear itself.
Only these four elements (sun gear, planetary gear, carrier, and shell internal gear) are displaced in the axial direction and cannot maintain the integrity. That is, the gear itself cannot maintain unity as a unit. This can be expressed as having no unity.

Therefore, various mechanisms are provided to prevent the sun gear and the carrier from sliding in the axial direction. These are mainly bearing mechanisms, and various radial bearings and slice bearings have been used. Other than bearings, there are also sleeves and the like. In the planetary gear device, a mechanism for preventing the transition in the axial direction other than the four elements is indispensable.

[0006] Since the planetary gear unit is liable to be abnormally meshed with each other, there have been many proposals in which a disk having a diameter equal to the pitch circle is added to both sides and one side of the gear. U.S. Patents 3299928, 3548673, 3789700,
1970251, 1586309, 3216270, 3
330171, 1425430, 4109545, German Offenlegungsschrift 2032723, German Patent 444697,
British Patent 1107062, Jiko 30-1691
8, Japanese Patent Publication No. 54-17111, Japanese Utility Model Publication No. 57-4148
6, and JP-B-57-48702.

A disk having a size equal to the pitch circle is provided on both sides and one side of the planetary gear. A ring with a pitch circle is also added to the internal gear. The pitch disk and the pitch ring are in sliding contact with each other without slipping, and have an effect of reducing the radial pressing force applied to the gear. Why pitch circles? The pitch disc is the effective circle of the gear. This is because in the case of contact between pitch disks, the peripheral speed is the same and there is no slip. In the case of the pitch disk, the planetary gear is composed of three members, and the internal gear is composed of three members. This is inevitable.
Since the pitch circle is located between the root circle and the addendum circle, it cannot be formed as one piece. Since the planetary gear is composed of three members, a cavity is formed inside. The inventor tried to fill grease inside a three-piece planetary gear. This was an unexpected gain of a three-piece gear. Such a thing is hard to expect with one gear. This can be achieved only when the ring of the external gear is fixed to the external gear by screws. There is no integral unit property by itself.

The present applicant has devised a novel planetary gear device in which a disk having the size of the tip circle is attached to both sides of the planetary gear, unlike the pitch circle. The internal gear, which is an internal gear, is provided with a cylindrical portion of a root circle on both sides. The tip circle and the bottom circle,
The peripheral speed is different because it is out of the pitch circle. It is difficult to follow the common sense of gear engineering. So no one ever suggested. Nevertheless, the applicant has dared to propose the tip circle method.

JP-A-58-94656 (Japanese Patent Application No. 56-1)
93113; Japanese Patent Publication No. 3-61061). The planetary gear consists of three members. There are three in the center gear part and the tooth tip disks on both sides. The internal gear having a root circle on both sides can be molded integrally with plastic. Since the teeth are internal teeth, the root circle is larger in diameter than the gear part and has a ring shape, so that it becomes a thinner part. The cost can be reduced by integrating the three members of the internal gear into one. The planetary gear is made up of three members and has a cavity. The cavity could be filled with grease.

This has an unexpected effect in addition to the main purpose of cost reduction. Oneness. When the disk of the addendum circle is attached to both sides of the planetary gear, the planetary gear can no longer be axially pulled out of the internal gear (outer shell internal gear). Neither the sun gear nor the planet gears can be pulled out. The external gear of the outer shell is made of a single piece of plastic. That is, uniformity can be ensured only by the four elements of the planetary gear device (carrier, planetary gear, sun gear, and shell internal gear). For the first time, the unity as a planetary gear unit was obtained.
This is something never before. This is the first planetary gear set that can maintain its integrity without complicated bearings and sleeves. The tip circle method is excellent in terms of unity and low cost. The present applicant has manufactured and sold a large amount of planetary gear units of the addendum type to date.

In the case of the tip circle type, the sun gear is confined by the disk of the planetary gear. Once assembled, the sun gear cannot be pulled out or inserted. It may be desirable to be able to insert the sun gear sideways after the unit has been assembled. The applicant has devised a planetary gear system having asymmetry for such purpose.

One is disclosed in Japanese Patent Application Laid-Open No. Sho 60-252845 (Japanese Patent Application No. 59-106976). The other is JP-A-61-27337 (Japanese Patent Application No. 59-150145) (US Patent 4,617,839, Chinese Patent 859, Australian Patent 553968, Korean Patent 24285). These have a planetary gear made up of three members, one of the gear portions having a disk with a tip circle and the other with a disk with a bottom circle. That is,
Planetary gear = small disk + gearing + large disk. Again, the planetary gear consists of three members. The root disk of the planetary gear is opened. Therefore, the sun gear can be inserted and removed from the root disk. The internal gear (outer shell internal gear) is also asymmetric, but it can be plastic molded as one piece. There are axially different types of inner diameters from the tooth tip cylinder, gear, and root cylinder, but the inner diameter monotonically increases in this order, so that the mold can be removed from the mold.

There is still room for improvement. If the asymmetric planetary gear is divided into three members, the cost increases. Since there are four or three planetary gears, there are 12 or 9 parts. Planetary gears as gearboxes are promising, but not widely used, in part because they are expensive. If the cost is lower, it will not spread widely. Reducers are strongly required to be low-priced. Even 10
It is important to be able to make even cheaper yen. Applicants' long-standing effort to replace what is metal with plastic has served its purpose. However, there is still a strong demand for low prices.

The inventor of the present invention has conceived of integrating the asymmetrical planetary gear, which has been divided into three members, into one member. The small disk portion, the large disk portion, and the gear portion of the planetary gear are combined into one member. Since the diameter is large disk part> gear part> small disk part, it can be manufactured by a mold and the product can be removed from the mold. This is Japanese Patent Publication No. 5-7575 (Japanese Patent Application No. 62-2622).
74, Japanese Patent Application Laid-Open No. 1-105039) "Integrated asymmetric planetary gear device" (U.S. Pat. No. 5,098,358, U.K. Pat.

[0015] The planetary gear can be made of one member, has unity and is inexpensive. It can be said that it is an ideal planetary gear set. It was a truly excellent invention. The present applicant manufactures and sells many planetary gear devices of this type.

[0016]

However, since it is a speed reducer, there is always a problem of lubrication. If not lubricated, excessive force is required, friction loss and noise are large, wear and wear are remarkable, and it cannot be used. Normally, the casing is housed in a casing, so the casing is filled with oil or grease and sealed. The entire gear is surrounded by the lubricant. Therefore, the frictional resistance can be reduced.
The lubricant was held by the casing. The planetary gear set itself did not have the effect of maintaining the lubricant.
This, however, required grease throughout the casing, which naturally required a large amount of grease. Although the grease effective for lubrication was small, grease was needed to fill the entire casing. This is useless.

However, as described above, in the case of the addendum circle type, since the planetary gear is composed of three members, a cavity is formed inside. If high-viscosity grease was put in the cavity, it acted as a lubricant. In that case, it is not necessary to fill the entire casing with the lubricant. This effectively utilizes the internal space of the planetary gear as a grease reservoir. The amount of grease can be reduced and grease can be used more effectively.

However, during the process of making the planetary gears asymmetric and integral, the planetary gears lost cavities. At the same time, it is no longer possible to store grease inside the planetary gears. Grease is viscous and can be applied to gears, but it is fine, but if it is applied to the open gear surface, it will not become thinner. Of course, grease can be retained in the casing, but if it is put in the casing, the probability of contact with the gears is low and it cannot be used effectively. Even at the beginning of rotation, even if it is in contact with the tooth surface, it is gradually pushed away and retreats. Even if it is inside the casing, it is useless if you do not touch the gears. To avoid this, the casing must be filled with grease. This is possible but requires a large amount of grease and is uneconomical. If the casing itself does not have a sealing property, the casing cannot be filled.

It is convenient to provide a mechanism for holding and storing grease in the planetary gear unit itself. The present invention has such an object. It is a first object of the present invention to provide a planetary gear device that can hold grease inside the device itself. It is a second object of the present invention to provide a planetary gear device that rotates smoothly and has little torque loss and little noise.

[0020]

SUMMARY OF THE INVENTION A planetary gear device of the present invention comprises a central sun gear, an appropriate number of planetary gears around and meshing with the sun gear, and a planetary gear around and meshing with the planetary gear. It includes a carrier consisting of a main carrier disk and a sub-carrier disk that rotatably support the planetary gears from both sides and the planetary gears. A planetary small circle having a diameter and a planetary great circle having a diameter equal to or larger than the addendum circle on the other side are formed as an integral unit. The outer shell small cylinder part which is located on one side and faces the planetary small circle part and has an inner diameter equal to or smaller than the tooth tip circle, and the outer shell located on the other side facing the planetary large circle part and having an inner diameter equal to or larger than the tooth bottom circle It consists of a large cylindrical part, which is molded as one piece. The main carrier has an outer diameter larger than the inner diameter of the outer shell and contacts the side of the outer shell small circle, and the outer surface of the main carrier disk has an outer diameter larger than the pitch circle of the outer shell gear. Part.

With this structure, if the space in which the planetary gears are present is first filled with grease, the grease is unlikely to leak. This is because the carrier has some ingenuity. Since the outer diameter of the sub-carrier plate is larger than the inner diameter of the small shell portion of the outer shell so as to be in contact with the side, the grease filled therein is confined by this. Since the main carrier disk is larger than the pitch circle of the internal gear of the outer shell, grease hardly leaks from here. Further, the gap between the outer shell large cylindrical portion and the end face of the main carrier board is small, so that it is hard to leak.
The main carrier panel and the sub-carrier panel on both sides prevent grease from leaking. The planetary gear device of the present invention effectively utilizes the asymmetrical gear to confine grease inside the carrier.

What needs lubrication is the gear meshing portion in the first place. There are two engaging parts. One is the meshing of the sun gear and the planetary gear. There are three or four of these. The centrifugal force causes a force in the direction in which grease is scattered, but since the grease is located at the center, the grease moves toward the planetary gear due to the centrifugal force. The other is the meshing of the planetary gear with the external gear of the outer shell. The centrifugal force is applied to press the grease against the outer ring gear. The grease then flows axially along the root of the external gear. On the one hand, outflow is hindered by the bulging of the small cylindrical portion of the outer shell. Further, the grease is prevented from coming off by the sub-carrier plate. The flow to the other is impeded by the overhang of the outer circle of the main carrier disk. This is the most important idea of the present invention.

Looking only at the cross-sectional view, the great circle portion of the planetary gear appears to hinder the axial flow of grease, but it is not very effective because the planetary gear is only a small part. The present invention seeks to contain the grease by the outer circumference of the main carrier disk, since the planetary gear disk is useless. This is the point of the present inventor's bone. If the main carrier has an outer circumference equal to or larger than the pitch circle of the internal gear of the outer shell,
The grease adhering to the outer ring gear cannot easily pass over the main carrier disk. The outer periphery of the main carrier board is opposed to the outer shell large cylindrical surface and the gap is small, so that leakage is small. For example, if the outer shell large cylindrical surface is a tooth bottom circle and the main carrier disk is a pitch circle, the gap between the outer shell large cylindrical portion and the main carrier disk is 1
There are only modules. Since it is viscous grease, it does not easily leak from small gaps.

Since the output shaft is inserted into the shaft hole of the main carrier panel, grease does not leak from here. There is a possibility that the sun shaft is inserted into the opening of the sub-carrier board and grease leaks from the gap between the sun shaft and the opening. By narrowing the opening of the sub-carrier board,
This can be prevented to some extent by reducing the gap with the sun axis. Further, if a sunshaft or the like is provided so as to close the opening, leakage can be further reduced.

Since the term "pitch circle" is used to limit the invention, the concept of pitch circle is defined. The effective circle expressing the effective diameter of the gear is the pitch circle. This circle is located approximately at the center between the root circle and the tip circle. In the case of external teeth, the circle outside the normal pitch circle by one module is the tip circle, and the circle inside the 1.25 module is the root circle. In the case of internal teeth, the circle inside one module from the pitch circle is the tip circle, and the circle outside the 1.25 module is the root circle. Between the module m, the number of teeth Z and the pitch circle diameter D,
The equation D = mZ has now been reached.

Further, in the asymmetric planetary gear device of the present applicant, the great circle portion of the external teeth is larger by 0 to 2 modules in radius than the addendum circle. The small circle is 0 to 2 modules smaller than the root circle. In the case of internal teeth, the large cylindrical surface is 0 to 2 modules larger than the tooth bottom. The small cylindrical surface is 0 to 2 modules narrower than the tooth tip.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is characterized by a structure capable of confining grease inside the planetary gear device itself. This will be described more specifically with reference to examples. FIG. 1 is a front view of a planetary gear device according to an embodiment of the present invention. FIG. 2 is a rear view. FIG. 3 is a central longitudinal sectional view of the same. FIG.
Is a front view of only the planetary gears, and FIG. 5 is a sectional view.

This planetary gear device is configured so that the sun gear can be inserted from the side after being assembled. This is possible because of the asymmetry. Of course, it is also possible to incorporate the sun gear from the beginning and insert the sun shaft afterwards. 1 and 2 show a state immediately after assembly without a sun gear. FIG. 3 shows a state where the sun gear is inserted.

In the assembled state, the sun gear is at the center. Three planetary gears 2, 2, 2 are provided on a circumference at a position having a central angle of 120 degrees so as to mesh with the sun gear. This is an axially asymmetric planetary gear. Plastic molding or powder metal is produced by a sintering method. Although it is a modified gear, it can be easily manufactured because it is formed by a mold.

Outside the planetary gears, a ring-shaped external gear (internal gear) 3 is provided so as to surround them. This is sometimes called a ring gear. Because it is ring-shaped. It is also called internal gear. This is because they have internal teeth. Here, since it is the outermost and has internal teeth, it is referred to as an outer shell internal gear. The outer shell internal gear (internal gear) 3 is also asymmetric. The external gear 3 also has an asymmetric and complicated shape, but is integrally formed by plastic molding.

The three planetary gears 2 described above are rotatably supported by a disk-shaped carrier 4. The carrier 4 is composed of two disks 4A and 4B. The reduced rotation is taken out of the carrier. The one that is thicker and more robust and to which the output shaft is coupled is referred to as the main carrier board 4A. The one through which the input shaft (sun axis) passes thinner is referred to as a sub-carrier board 4B. The planet gears 2, 2, 2 are penetrated by a planet shaft 5, and both ends of the planet shaft 5 are supported by a main carrier plate 4A and a sub-carrier plate 4B. Main carrier panel 4A and sub-carrier panel 4
B are interconnected.

The planetary gear 2 is an asymmetric gear. 4 and 5 show an enlarged front view and a sectional view of only the planetary gear 2. One planetary gear 2 is integrally formed but has three different parts in the axial direction. At the center is a wide planetary gear section 6. In FIG. 3, a planetary small circle portion 7 is located on the left side of the planetary gear portion 6.
There is a planet great circle part 8 on the right side. Planet small circle part 7,
It has a diameter equal to or smaller than the root circle of the planetary gear portion 6. The planetary great circle portion 8 has a diameter equal to or larger than the addendum circle of the planetary gear portion 6. It may be larger by about 2 modules than the radius of the addendum circle.

The diameters of the three parts are in increasing order. These three parts are hub 9 near the axis center.
Will be integrated. The hub 9 is still narrower than the width of the gear portion 6. This is to save material and to provide a space to build up inside the carrier 4 for reinforcement.
The hub 9 has a shape in which a shaft hole 11 is bored. Three such integrated asymmetric planetary gears are used, but of course four may be used.

Such gear asymmetry is unique to the applicant. There is no other example. As described above, such an asymmetric type used a three-part planetary gear at first, but in order to reduce the cost, an integrated type was devised. This embodiment also uses an integrated type. Because it is an integral type, there is no cavity inside the planetary gear itself.

The planetary gear having such asymmetry can be removed by opening the split mold before the great circle portion 8. Therefore, the planetary small circle portion 7 is the same as or smaller than the tooth bottom.

The external gear 3 is naturally asymmetric. An outer shell gear portion 12 is provided at the center, an outer shell small cylindrical portion 13 is provided on the left side, and an outer shell large cylindrical portion 14 is provided on the right side. The inner diameter of the outer shell small cylindrical portion 13 is equal to or smaller than the addendum circle of the outer shell gear portion 12. A radius smaller than about 2 modules is allowed. The inner diameter of the outer shell large cylindrical portion 14 is equal to or larger than the root circle of the outer shell gear portion 12. This is also allowable up to about two modules in radius. The outer shell gear 6 meshes with the planetary gear 12. The planetary small circle portion 7 faces the outer shell small cylindrical portion 13. The planet great circle portion 8 faces the outer shell great circle portion 14.
These cylindrical disk portions may contact each other in the radial direction, but may be separated from each other.

These outer shell large cylindrical portion 14, planetary great circle portion 8,
The outer shell small cylinder portion 13 and the planetary small circle portion 7 exert a radial force, but what is more important is the integrity by preventing the axial direction from coming off. When used as a speed reducer for a washing machine, use it sideways. The main carrier board 4A to which the output shaft is connected is supported on the upper side, and the sub-carrier board 4B into which the input shaft is inserted is supported on the lower side.

In this case, even if only the external gear 3 is supported, the carrier 4 does not fall down. The side surface of the planet great circle portion 8 is supported by the side surface of the outer shell gear portion 12. The side surface of the planetary gear unit 6 is supported by the side surface of the small shell 13. As a result, the carrier 4 does not come off to the side of the sub-carrier board 4B. Furthermore, the outer peripheral edge 2 of the sub-carrier board 4B
9 is in contact with the side surface of the small shell portion 13 so that it does not come off in the opposite direction. These cylindrical parts,
The carrier remains in a certain position by the combination of the disc parts. Such is not possible with a conventional planetary gear without a conventional disc or the like. The four main members ensure the integrity.

The main carrier board 4A and the sub carrier board 4B are fixed to each other as follows. The first raised portions 16 are formed at three places at an angle of 120 ° on the back surface of the main carrier board 4A. A columnar projection 19 further projects from the first raised portion 16. A second raised portion 17 is also formed on the back surface of sub-carrier plate 4B. A stop hole 18 passes through the second raised portion 17 in the axial direction. Main carrier board 4
A, the sub-carrier board 4B is made by aluminum die casting or plastic injection molding. It is also possible to make only the main carrier plate 4A to which a force is applied, made of Al, and to make the sub-carrier plate 4B, which does not apply much force, a plastic.

The two carrier boards are connected by inserting the projection 19 of the main carrier board 4A into the stop hole 18 of the sub-carrier board 4B and caulking the tips. Main carrier board 4
When A is Al, they are joined by the caulking portion 20 like that. When the main carrier plate 4A and the sub-carrier plate 4B are made of plastic, they are fixed by ultrasonic welding or an adhesive.

Although the carrier coupling mechanism is provided at three positions, the planetary gear 2 and the planetary shaft 5 are provided at a position exactly intermediate between them. In order to hold the planet shaft 5 that penetrates the planet gear 2,
The main carrier board 4A and the sub-carrier board 4B have anti-spin protuberances 23 and 24 inside. Shaft holes 25 are drilled in these ridges 23 and 24. The planet shaft 5 passes through the shaft hole 11 of the planetary gear 2, and both ends thereof are fixed by the shaft holes 25. The planet gear 2 turns around the planet shaft 5.

The center boss 30 of the main carrier board 4A has a carrier shaft hole 21. A shaft hole into which the output shaft is inserted. It has suitable detent mechanisms such as splines, serrations, and the like. In this example, the root diameter is 12 mm and the number of teeth is 11
, The involute serration of module 1. The reason why the boss 30 is thicker is that the output shaft is connected here and a strong torque is applied to reinforce the boss.

The sub-carrier board 4B is thinner because no force is applied. If it is a metal such as Al, the strength is perfect,
It may be plastic. The sub-carrier board 4B has an input shaft opening 22 into which the input shaft is inserted. Since the input shaft is connected to the sun gear, it does not come into contact with the sub-carrier board. The opening 22 should not be in contact with the input shaft (sun axis) and should be as narrow as possible.

The structure of the planetary gear unit has been roughly described above. In this example, the sun gear can be inserted from the side after assembling the unit. For this purpose, the sun gear is integrated with the shaft. When integrated with the shaft, it is convenient to insert it from the side, and it can also serve as a shaft for transmitting input torque. A stronger torque can be applied. If a sun gear is provided at the tip of the shaft, the diameter of the sun gear can be further reduced. Reducing the number of teeth of the sun gear can increase the reduction ratio. This is convenient for obtaining a high reduction ratio.

The combination of the input shaft and the sun gear is called a sun shaft 31. The sun shaft 31 has a sun gear 32 formed at the tip. There is a large diameter flange 33 at the base. It is followed by a shaft 34.

An object of the present invention is to provide a structure for confining grease for lubrication inside the planetary gear device itself. Grease is injected between the two carrier boards 4A, 4B. Between the main carrier plate 4A and the sub-carrier plate 4B, there are three planetary gears 2 and three (or sometimes four) raised portions, but there is still extra space. Grease fills that space. Further, grease enters the space between the hub 9 of the planetary gears and the two carrier disks. A lubricating film is formed to fill between the planet shaft 5 and the shaft hole 11. Sun gear 1
The grease meshes with the meshing tooth surface of the planetary gear 2. The grease also covers the meshing tooth surface of the planetary gear 2 and the internal gear 3. A large amount of grease is present on the contact surface of the tooth surface. Grease reduces torque loss in tooth meshing. Reduces friction, reduces noise and prevents tooth surface wear and tear. Reduces heat generation by reducing friction. It absorbs and conducts heat and transmits it to the carrier disk and the internal gear of the outer shell, and radiates heat through the casing. In addition, it absorbs noise and does not leak outside. Grease plays a variety of roles.

As is evident, a great deal of ingenuity is required to maintain such a state. Heat is generated because the gears rotate at high speed. The heat reduces the viscosity of the grease. Grease enhances fluidity. The gear generates centrifugal force and pushes grease to the outer shell. If there is no stop,
Grease escapes to the outside.

FIG. 6 shows a sectional view of the same planetary gear device.
It is a cross section in the direction from which the planetary gears and the ridge are removed. Usually such a cross section is not made, but in order to clarify the presence of grease, a cross section in the direction without the planetary gears and the coupling mechanism is drawn. Thus, both carrier boards 4A,
A grease reservoir space surrounded by 4B and the external gear 3 is formed. The sun shaft 31 is inserted from the sub-carrier board and the opening 22 of 4B, and the sun gear 32 at the tip is located exactly at the center of this space. Carrier shaft hole 21 of main carrier panel 4A
Is provided with an output shaft 60. Therefore, grease does not leak from the carrier shaft hole 21.

There is a possibility that the grease G filled between the outer ring gear and the carrier disk may escape from the three openings X,
This is from Y and Z. The opening X is between the input shaft opening 22 of the sub-carrier board 4B and the flange 33 of the sun shaft 31. This gap is equal to the diameter of the flange or the opening 2 of the sub-carrier board 4B.
(2) The inner diameter can be appropriately determined and narrowed. In addition, since it is in the center, the centrifugal force is small and leakage hardly occurs.

The opening Y is an opening formed between the sub-carrier board 4B and the small shell 13 of the outer shell. Even if grease accumulates at the tooth bottom of the outer shell internal gear, the outer shell small cylindrical portion 13 is higher
Does not allow grease leakage. Further, in the present invention, the outer peripheral edge 29 of the sub-carrier board 4B is extended more widely than the inner diameter of the outer shell small cylindrical portion 13. The outer peripheral edge 29 is in circumferential contact with the side surface of the outer shell small cylindrical portion 13. The sub-carrier board 4B prevents grease leakage from the opening Y. The grease is prevented from leaking at the opening Y by the double sealing mechanism.

The third opening Z is provided with the right outer shell gear 1
2 is a route that escapes from the outer cylinder 2 to the outer shell large cylindrical portion 14. This leakage is the most problematic. However, in the present invention, the main carrier plate 4
Since the outer peripheral edge 28 of A extends outside the pitch circle of the outer ring gear 3 or more, grease leakage can be prevented. This is because the gap between the outer shell large cylindrical portion 14 and the outer peripheral edge 8 is narrow. Since the outer peripheral edge is wider than the pitch circle and the outer shell large cylindrical portion 14 is set to be 0 to 2 modules larger than the root circle, the upper limit of the gap is 3 modules. However, it is preferably smaller than two modules. Further, it may be one module. It is also possible to make the outer diameter of the main carrier disk the root circle of the external gear.

If, for example, the outer diameter of the main carrier disk 4A is the pitch circle of the outer shell internal gear and the outer shell large cylindrical portion 14 is the root circle, the gap is one module. If the module is a 0.9 gear, the gap is 0.9 mm. For example, the outer shell large cylindrical portion 14 is retracted 0.5 mm from the tooth bottom, and the main carrier disk 4
If the outer diameter of A is a root circle, the gap is 0.5 mm.

The outer peripheral edge 28 is made as close as possible to the outer shell internal gear large cylindrical portion 14 as long as the main carrier disc 4A does not contact the outer shell internal gear. The lower limit of the gap depends on the manufacturing accuracy. The main carrier disk and the outer shell large cylindrical surface must not touch. Depending on the dimensions of the carrier and the manufacturing accuracy, the gap should be 0.
It is easy to narrow it to about 3 mm. If the plastic molding accuracy is good, the gap can be reduced to 0.1 mm. For this reason, leakage from the opening Z can be minimized.

Only four members (sun gear, carrier, planet gear, and shell internal gear) of the planetary gear device can be long confined in grease. Good lubrication can be guaranteed for many years. Noise is less likely to occur due to good lubricity. Even if there is noise, grease does not go outside because it has the function of absorbing sound and vibration.

[0055]

According to the present invention, the outer peripheral edge of the main carrier disk is widened from the pitch circle of the external gear of the outer shell, and the gap between the main carrier disk and the outer cylindrical portion is extremely narrow. The sub-carrier plate is almost in contact with the side surface of the small shell portion of the outer shell. The grease injected between the main carrier panel and the sub-carrier panel is stably present between the carrier panels and does not leak to the outside. Grease can be confined by only four members of the planetary gear set. The function of retaining grease is given to the planetary gear device itself. Grease can be retained without depending on the casing.

Grease is always abundantly sun gear, planetary gear,
The gears rotate smoothly because they exist between the outer ring gears. Low torque loss. Friction is reduced. Attrition is reduced. Less friction loss and less noise due to grease absorbing sound. Approximately two-phone noise level was reduced as compared with the conventional one. Since the lubrication is good, there is no wear or breakage of the gear.

Further, since the sub-carrier disc presses the side surface of the small shell portion of the outer shell, the carrier does not come off in the direction of the main carrier disc. The carrier does not come off in the direction of the sub-carrier plate, because the planetary cylindrical portion presses the side surface of the outer gear portion. The integrity can be maintained regardless of the casing.

[Brief description of the drawings]

FIG. 1 is a front view of a planetary gear device according to an embodiment of the present invention.

FIG. 2 is a rear view of the planetary gear device according to the embodiment of the present invention.

FIG. 3 is a vertical left side view of the planetary gear device according to the embodiment of the present invention.

FIG. 4 is a front view of one planetary gear in the planetary gear device.

FIG. 5 is a longitudinal sectional view of a planetary gear.

FIG. 6 is a cross-sectional view of the same planetary gear device cut in a direction other than a planetary gear and a coupling ridge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Planetary gear device 2 Planetary gear 3 Shell internal gear 4 Carrier 4A Main carrier board 4B Subcarrier board 5 Planetary shaft 6 Planetary gear section 7 Planetary small circle section 8 Planetary large circle section 9 Hub 10 Flat peripheral surface 11 Shaft hole 12 Outer shell gear part 13 Outer shell small cylindrical part 14 Outer shell large cylindrical part 15 Non-rotating tooth shape 16 First raised part 17 Second raised part 18 Stop hole 19 Projection part 20 Caulking part 21 Carrier shaft hole 22 Input shaft opening 23 Shaft Stop ridge 24 Shaft stop ridge 25 Shaft hole 27 Cavity 28 Outer edge 29 Outer edge 30 Boss 31 Sun shaft 32 Sun gear 33 Flange 34 Shaft 60 Output shaft

Claims (1)

(57) [Claims] 1. A central sun gear, an appropriate number of planetary gears around and meshing with the sun gear, a shell internal gear around the planetary gear and meshing with it, and a planetary gear from both sides. Including a carrier comprising a main carrier disk and a sub-carrier disk rotatably supported, the planetary gear has a center planetary gear portion, and a small planetary circle portion on the side thereof having a diameter equal to or less than the root circle,
On the other side, there is a planetary great circle portion having a diameter of 0 to 2 modules larger than the addendum circle, and these are molded as an integral body. And an outer shell small cylindrical portion facing the planetary small circle portion and having an inner diameter equal to or smaller than the tip circle, and an outer shell having an inner diameter of 0 to 2 modules larger than the tooth bottom circle and located on the other side and facing the planetary large circle portion. The sub-carrier plate has an outer diameter larger than the inner diameter of the outer shell small cylinder portion and is in contact with the side surface of the outer shell small cylinder portion. A grease self-holding planetary gear device having an outer diameter larger than a pitch circle of an outer shell gear portion, wherein the entire width of an outer peripheral surface of a main carrier board is opposed to an outer shell large cylindrical portion.