JP2922476B2 - Planetary gear without sub-carrier panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a planetary gear device. In particular, the present invention relates to a planetary gear device that aims at cost reduction by reducing the number of members. The planetary gear system is a sun gear,
This is a device consisting of a planetary gear, a shell internal gear, and a carrier. When the central sun gear rotates, the planetary gear meshing with the sun gear revolves while rotating. When the outer ring gear is fixed to the casing, the carrier rotates at a reduced speed. The main purpose of the planetary gear device is to reduce the rotation of the sun gear and output the rotation to the carrier. Conversely, it can also be used as a gearbox that increases the rotation of the carrier and outputs it to the sun gear. The application is wide as various speed reduction mechanisms. Planetary gear devices of various shapes are manufactured and used depending on the application.

[0002]

2. Description of the Related Art A planet gear is rotatably supported on a carrier by a planet shaft. A bearing may be interposed between the planetary shaft and the planetary gear, but this would be expensive, so that the shaft is often slipped through the shaft hole. The two ends of the planet shaft are supported by two wide disks. This disc is referred to herein as a carrier. The carrier is a member on which the output shaft is to be mounted, and rotates at a reduced speed. The carrier is composed of two disks on both sides of a planetary gear or a sun gear. These have functions of supporting the planetary shaft from both sides, outputting reduced rotation, and supporting the planetary gear between them. The carrier board with the output holes is called the main carrier board, and the carrier board without it is called the sub-carrier board. They are disks of the same diameter. Strong torque is applied to the main carrier panel. The sub-carrier board and the main carrier board are connected to each other. Let M be the number of planetary gears. M is often 3 or 4. M ridges are made inside both plates and one of the ridges is pinned with a pin in the other, and the pin is inserted into the hole and crimped. When there are three planetary gears, three ridges are formed respectively, and the two are connected.

[0003] The main carrier disk and the sub-carrier disk rotate integrally. The two ends of the planetary shaft are simply inserted into the holes, but the planetary shaft does not come off because the two carrier disks are fixed. As described above, it is a common structure in any conventional planetary gear device that the carrier is composed of two members and they are interconnected by some coupling mechanism. The structure is too commonplace.

[0004]

Various modifications are made to the planetary gear device depending on the purpose, but the present invention mainly aims at cost reduction. The cost includes the manufacturing cost and the assembly cost of gears and carriers. The sun gear, the planetary gear, the external gear of the outer shell, the carrier, the planetary shaft and the like are absolutely necessary. There seems to be no room for further reduction. Nevertheless, demands for cost reduction are severe and efforts to further reduce costs are desired. SUMMARY OF THE INVENTION It is a first object of the present invention to provide a planetary gear device that can reduce the number of members and the cost of parts in response to such demands. It is a second object of the present invention to provide a planetary gear device capable of reducing the assembly cost accordingly. A third object is to provide a planetary gear device suitable for multi-stage connection.

[0005]

SUMMARY OF THE INVENTION A planetary gear device according to the present invention is one in which one of the two carriers is omitted, and the structure for coupling the carriers is also omitted. That is, except for the sub-carrier board, a mechanism for connecting the sub-carrier board and the main carrier board is not required. The planet gears are supported by a planet shaft, which is cantilevered by a main carrier board. Conveniently, the planet shaft is further molded as one piece with the main carrier disc. The main carrier panel may be provided with output holes. In the case of multi-stage connection, it is even better if the sun gear of the next stage is fabricated on the main carrier board. Since the carrier is a single member, there is no need for a mechanism for coupling the two. That also greatly contributes to cost reduction.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the planetary gear device of the present invention, a carrier which supports a planetary gear and from which reduced rotation is taken out is constituted by a single disk. Four or three planetary shafts are set up on one main carrier panel, and planetary gears are rotatably provided here. The planet shaft becomes cantilevered. One side of the planet gear comes in contact with the main carrier board, so it does not come off. The housing is extended to the front so that it does not come out on the opposite side and holds the planetary gears. Therefore, the planetary gear does not come off the shaft. In addition, a disk part of the tip circle and a disk part of the root circle are provided on both sides of the planetary gear, and a cylinder part of the root circle and a cylinder part of the tooth circle are formed on both sides of the external gear. It is preferable that the planetary gear and the external gear of the outer shell be brought into contact with each other. This prevents axial translation of the planetary gear. The axial position of the planetary gear is reliably determined by the action of the carrier and the external gear. Since two carrier plates are not used, a structure for connection is not required. Of course, no joining work is required.

[0007]

1 is a left side view of a planetary gear device according to an embodiment of the present invention, FIG. 2 is a right side view, and FIG. 3 is a sectional view taken along line XX of FIG. FIG. 4 is a sectional view taken along line YY of FIG. This is 2
Although the case of step connection is shown, three step connection is also possible. Of course, it is also possible to use one stage. The first stage is referred to as a first unit A, and the second stage is referred to as a second unit B for distinction. In each case, there is no sub-carrier plate and there is only one carrier plate. Similar but not identical.

The first unit A in the preceding stage has a sun gear 1 at the center and four planetary gears 2 surrounding it.
The planetary gear 2 meshes with the sun gear 1. Planetary gear 2
May be four or three, or five if the reduction ratio permits. Further on the outer side of the planetary gear 2, there is a shell internal gear 3 which meshes with all of the planetary gears 2. The planetary gear 2 is rotatably supported by a planetary shaft 5 integrated with the main carrier board 4. In the conventional apparatus, the planetary shaft 5 is supported at both ends by the sub-carrier disk and the main carrier disk. In the present invention, the planetary shaft 5 is supported only by the main carrier disk. That is, in the conventional planetary gear device, the carrier is composed of the sub-carrier disk and the main carrier disk, and the planetary gear is sandwiched between both. However, in the present invention, there is no sub-carrier disk.

The external gear 3 is formed in a part of the housing 6. The housing 6 is a U-shaped member including a cylindrical portion 7 and a front disk portion 8. The cylindrical portion 7 is a casing that covers the front of the planetary gear and the external gear of the external shell, and is a support member for the internal gear of the external shell. In the case of the conventional planetary gear device, the front of the planetary gear is covered by the auxiliary carrier disk, but in the present invention, the housing 6 protects the front of the planetary gear instead. A detent 9 is provided on the outer periphery of the housing 6. This is to prevent the planetary gear set from rotating with respect to the casing when the planetary gear set is placed in a casing (not shown).

A cylindrical sleeve 10 is inserted between the planet shaft 5 and the hole of the planet gear. This is to reduce frictional resistance and wear of the rotation of the planetary gear 2. The sleeve 10 is, for example, stainless steel. A circular stop ring 11 is fitted into the hole of the planetary gear 2. A gap 12 is formed between the retaining ring 11 and the end face of the planet shaft 5. In this example, the main carrier board 4 and the planet shaft 5 are integrally formed. A through hole 13 is formed in the planetary shaft 5 in the axial direction. Stop ring 11
Also has a through hole 14. Grease is injected from the through hole 14 and grease is accumulated in the gap 12 and the through hole 13. Thereby, lubricity between the planet shaft 5 and the planetary gear 2 is enhanced.

The sun gear 1 has a sun shaft hole 15 into which an input shaft such as a motor shaft is inserted. Here, a D hole is shown here to prevent rotation, but a spline or serration may be used here. A front opening 16 is provided in front of the housing 6 so that an input shaft (not shown) passes therethrough. Unlike a normal planetary gear or an external gear of a shell, a triple gear is used here. The planetary gear 2 has a planetary gear 17 in the center, a large circle portion 18 on the right side, and a small circle portion 19 on the left side. The great circle portion 18 has a disk shape having a diameter larger than the addendum circle. The small circle portion 19 has a circular shape with a diameter smaller than the root circle. These are in contact with the corresponding surface of the external gear 3 to guide the movement of the planetary gear 2.

The external gear 3 is formed on the inner periphery of the housing 6. The internal gear 3 also has a triple structure. An outer gear 20 is provided at the center, and a large cylindrical portion 21 and a small cylindrical portion 22 are provided on the right side. Have. The large cylindrical portion 21 is larger than the root circle of the gear portion 20. The small cylindrical portion 22 is smaller than the tip circle of the gear portion. The gear portion 20 of the external gear 3 meshes with the gear portion 17 of the planetary gear 2. The small cylindrical portion 22 on the left is in contact with the small circular portion 19 of the planetary gear. The right large cylindrical portion 21 contacts the great circle portion 18 of the planetary gear. Such an integrated triple structure is disclosed in Japanese Patent Publication No. 5-7575 (JP-A-1-10539:
Japanese Patent Application No. 62-262274) for the first time. The asymmetric triple structure in which the planetary gear is separated into three members is that of the previous stage.
No. 2845 and JP-A-61-27337.

Such a stepped structure has the effect of correctly determining the relative positions of the planetary gear 2 and the external gear 3 in the diameter direction. Not only that. This has the effect of inhibiting the movement of the gear in the axial direction and enhancing the integrity of the planetary gear device. The sun gear 1 does not retract any further due to the great circle 18 of the planetary gear 2. Planetary gear 2 despite the absence of sub-carrier
Is not pulled out forward because the gear portion 17 contacts the side surface of the step portion 60 of the housing 6. Although it is cantilevered, since the small cylindrical portion 22 of the planetary gear 2 comes into contact with the inner periphery of the step portion 60, this acts as a bearing so that the planetary gear 2 can orbit correctly.
Since the small circle portion, large circle portion, small cylinder portion, large cylinder portion and the like have the same action as such a bearing, it is not necessary to provide a bearing again. Further, disadvantages due to the absence of the sub-carrier plate can be compensated. Further, since there is asymmetry in this direction, the assembling operation is simple. The planet gears are formed all at once by plastic, casting, or die casting.

It is a remarkable feature of the present invention that the carrier is made of a single disk 4. However, in the case where the carrier is connected in multiple stages, further improvement can be made. Here, a hole 2 is formed inside the shaft portion 24 which integrally forms the shaft portion 24 on the back surface of the main carrier board 4.
5 is pierced. This has the effect of saving carrier material. By storing grease also in the hole 25, the meshing between the first stage gears can be made smooth.
A second sun gear 26 is formed on the surface of the shaft portion 24 in the axial direction. In other words, the main carrier panel integrates the carrier, the second stage sun gear, and the joint connecting the carrier and the carrier. This reduces the number of parts and facilitates assembly. Unit B performs the second-stage deceleration.
Four planetary gears 27 are arranged on the circumference so as to mesh with the sun gear 26. The planetary gear 27 has a wider tooth width than the planetary gear 2 at the preceding stage. This is because a larger torque is applied to the second stage.

The planetary gear 27 meshes with the outer shell gear 28 on the outer side. The planet shaft 30 is the main carrier board 2
9 are integrally formed. The main carrier board 29 can be made of plastic such as polyacetal. The external gear 28 is formed on a part of the inner periphery of the housing 31.
The external gear 28 also has a larger tooth width than that of the preceding stage. The housing 31 is a U-shaped case having a cylindrical portion 32 having an outer shell internal gear 28 on the inner surface and a front disk portion 33 supporting the front surface of the planetary gear. An opening 34 is formed in the center of the front disk 33, and the opening 34 is formed in the center of the front carrier 4.
A shaft 24 extending therefrom penetrates. A cylindrical sleeve 35 is inserted between the planet shaft 30 and the inner surface of the planet gear 27. The sleeve 35 is made of metal such as stainless steel. Since the planet shaft 30 is made of the same material (plastic) as the carrier, the sleeve 35 is passed through to prevent abrasion. A rotation occurs between the sleeve 35 and the planetary gear 27, during which the sliding friction is reduced by grease or lubricating oil.

The carrier is usually composed of two disks, but the second-stage speed reducer also comprises a carrier with only one disk, omitting the auxiliary carrier disk. This is called the main carrier board. The main carrier board 29 has a planetary shaft 30 formed integrally therewith, and the boss portion 36 has a carrier shaft hole 37 formed therein.
The planetary gear 27 also has a triple structure. It has the same shape as the previous one, but the tooth width is large. Because the torque is large, the width of the teeth is widened accordingly. The planetary gear and the internal gear of the outer shell are also devised in the same manner as the first stage. A large circle portion 40 is formed on the right side of the planetary gear 27, a planetary gear portion 41 is formed in the center, and a small circle portion 42 is formed on the left side.
Such asymmetry is unique to the inventor. Correspondingly, the outer shell internal gear has a large cylindrical portion 43 on the right side, an outer shell gear portion 44 on the center portion, and a small cylindrical portion 45 on the right side. Since the outer ring gear is provided integrally with the housing 31, it is extremely easy to form such a stepped gear. It can be made all at once because of plastic injection molding.

On the right side, the great circle portion 40 of the planetary gear comes into rolling contact with the great circumference portion 43 of the outer ring gear. On the left side, the small circle portion 42 of the planetary gear comes into rolling contact with the small circumferential portion 45 of the outer shell internal gear. At the center, the gear 41 of the planetary gear meshes with the gear 44 of the internal gear of the outer shell to transmit torque. A through hole 46 is formed in the planetary shaft 30 of the main carrier disk 29 in the axial direction. This also has the same structure as the main carrier panel 4 in the preceding stage. Further, a stop ring 48 is fitted into the hole of the planetary gear. A hole 55 is drilled in the retaining ring 48. By injecting grease through the through hole 46, the grease reservoir 47 and the space such as the through hole 46 and the hole 55 can be filled with grease. This ensures lubricity between the sleeve 35 and the planet gear hole. In addition, lubrication can be imparted to the meshing of the gears of the planetary gear and the internal gear of the outer shell and the contact surface between the cylindrical portion and the circumferential portion.

The boss 36 of the main carrier panel 29 has a hole 51 in which the projection 53 of the shaft 24 of the main carrier panel 4 in the preceding stage is inserted.
Is plugged in. The side surface of the planetary gear 27 comes into contact with the inner surface of the main carrier board 29 and is prevented from falling off. The housing 6 of the unit A and the housing 31 of the unit B are prevented from rotating and fixed by being commonly inserted into the casing. The sun gear 1 is fitted with a high-speed small-torque input rotating shaft such as a motor shaft. As a result, the main carrier board 4 rotates at a reduced speed. Since this rotation becomes the rotation of the sun gear 26 in the next stage, the speed is further reduced in the next stage. Since the vehicle is decelerated in two stages, the total reduction ratio is the product of the two reduction ratios.

In this embodiment, the housing can be made of plastic (Duracon, polyacetal). The main carrier board is also made of plastic.
Since this requires a torque, a fiber or the like may be inserted for reinforcement. Planet gears are made of plastic or sintered metal, aluminum die cast, zinc, and the like.
The sleeve is made of stainless steel or plastic. The sleeve may be omitted. In this embodiment, there is no mechanism for preventing the second-stage main carrier panel from slipping rightward. Since the main carrier panel is held down by the output shaft, it does not actually come off.

Although a two-stage speed reducer is shown here, the present invention can also be applied to a one-stage speed reducer. In this case, a carrier having a carrier shaft hole in the boss portion, such as the second stage carrier in FIG. 4, can be used. Of course, even in the case of one-stage deceleration, it can be made like the first-stage carrier in FIG. In this case, since the deceleration output comes out to the shaft portion 24, the load can be rotated by this. In this example, the planet shaft and the main carrier disk are formed as a single unit by plastic molding, but instead, a metal planet shaft may be set up on a disc-shaped carrier.

[0021]

According to the present invention, one of the carrier plates (sub-carrier plate) is omitted, and the carrier is constituted by only one disk (main carrier plate). Material cost can be reduced by omitting one large disk member. In addition, since there is only one sheet, there is no need for a mechanism for connecting the two members.
Further, since the labor for connecting the two members is not required, the manufacturing process can be simplified. Together, the effect of cost reduction is great. Although the main carrier disk and the planetary shaft can be formed as separate members, the integration of the main carrier disk and the planetary shaft as in the embodiment is effective in further reducing the component cost. The work of assembling the planetary shaft and the main carrier panel is also unnecessary.

[Brief description of the drawings]

FIG. 1 is a front view of a planetary gear device according to an embodiment of the present invention in which two stages are connected.

FIG. 2 is a rear view of the same.

FIG. 3 is a sectional view taken along line XX of FIG. 4;

FIG. 4 is a sectional view taken along line YY of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sun gear 2 Planetary gear 3 Outer shell internal gear 4 Main carrier board 5 Planetary shaft 6 Housing 7 Cylindrical part 8 Front disk part 9 Rotation stop 10 Sleeve 11 Stop ring 12 Grease reservoir 13 Through hole 14 Through hole 15 Sun shaft hole 16 Front opening 17 Gear part 18 Large circle part 19 Small circle part 20 Outer shell gear part 21 Large cylinder part 22 Small cylinder part 23 Shoulder part 24 Shaft part 25 Hole 26 Sun gear 27 Planetary gear 28 Shell internal gear 29 Main carrier Board 30 Planetary shaft 31 Housing 32 Cylindrical part 33 Front cylindrical part 34 Opening 35 Sleeve 36 Carrier boss part 37 Carrier shaft hole 40 Large circle part 41 Gear part 42 Small circle part 43 Large cylinder part 44 Outer gear part 45 Small cylinder part Reference Signs List 46 through hole 47 grease reservoir 48 retaining ring 49 planetary gear side surface 50 inner surface of main carrier board 51 positioning hole 53 tip of carrier

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 1/28

Claims (1)

(57) [Claims] 1. A sun gear, a plurality of planet gears surrounding and meshing with the sun gear, a planet shaft rotatably supporting the planet gear, a carrier supporting the planet shaft and revolving, and a planet gear surrounding the sun gear. The carrier comprises only a disk on one side of the planetary gear, the carrier does not exist on the other side of the planetary gear, and the carrier cantileverly supports the planetary shaft. Thus, the planetary gear has a central gear portion, a small circle portion formed farther from the carrier and having a diameter smaller than the root circle, and a large circle portion formed closer to the carrier and having a diameter larger than the addendum circle. The inner gear of the outer shell has a small cylindrical portion having a smaller diameter than the center outer shell gear portion and a tip circle formed farther from the carrier and a larger cylindrical portion having a larger diameter than the root circle formed closer to the carrier. Including a cylindrical part, the gear part of the planetary gear and the outside The outer gear portion of the internal gear meshes with the gear, the small circular portion of the planetary gear and the small cylindrical portion of the external gear make rolling contact, and the large circle portion of the planetary gear and the large cylindrical portion of the external gear. Are in rolling contact, and contact between the side surface of the outer gear portion of the outer ring gear and the inner surface of the large circle portion of the planetary gear, and contact between the inner surface of the small cylindrical portion of the outer ring gear and the gear side surface of the planetary gear. A planetary gear device without a sub-carrier plate, characterized in that the planetary gear is prevented from displacing in the axial direction opposite to the carrier of the planetary gear.