JP6120618B2 - Planetary gear device - Google Patents

Description

  The present invention relates to a planetary gear device.

  There is a strong demand for weight reduction in various parts such as automobile-related parts. The same applies to the planetary gear device. Patent Documents 1 to 3 describe planetary gear devices using resin.

JP-A-3-223547 JP 2012-82842 A JP 11-346469 A

  In conventional planetary gear devices, priority is given to securing strength, and metal sintered parts are used as the main parts. In this case, strength and durability can be ensured, but there is a problem in reducing the weight. In such a background, an object of the present invention is to provide a planetary gear device that can be reduced in weight while ensuring necessary strength.

The invention according to claim 1 is a planetary gear device including a planetary gear mechanism unit that is connected in series from the drive side to the output side and decelerates the rotation transmitted from the drive side to the output side. there, the plurality of planetary gear mechanisms unit, the N which is arranged on the first planetary gear mechanism unit and the drive-side arranged on the output side (N is a natural number of 2 or more) and a planetary gear mechanism unit Each of the plurality of planetary gear mechanism units includes a plurality of planetary gears meshed with a fixed internal gear and a sun gear disposed inside a cylindrical frame made of metal, and the plurality of planetary gears are rotatable. And a carrier that is rotatable inside the frame, and the planetary gear of the first planetary gear mechanism unit is made of metal, and the first planetary gear of the fixed internal gear is First internal gear meshing with the planetary gear of the gear mechanism unit is constituted by a metal, a planetary gear of the planetary gear mechanism unit of the second N is constituted by a resin, the planet of the first N of the fixed internal gear The Nth internal gear meshing with the planetary gear of the gear mechanism unit is made of resin , and the Nth internal gear is accommodated in an accommodating portion formed by expanding the inner diameter of the inner peripheral portion of the frame. The planetary gear device is characterized in that the planetary gear device is fixed to the frame in a closed state .

  The present invention is basically based on a configuration in which a plurality of planetary gear mechanism units are connected in series, and the input side rotation is sequentially decelerated each time the number of stages passes and appears on the output side. Here, the first planetary gear mechanism unit disposed on the output side is a planetary gear mechanism unit that drives the output shaft of the planetary gear device. The N-th (N is a natural number of 2 or more) planetary gear mechanism unit arranged on the drive side is a planetary gear mechanism unit driven by a drive source such as a motor. Each planetary gear mechanism unit receives the rotation of the sun gear of the preceding planetary gear mechanism unit by its planetary gear, and outputs the rotation of the carrier generated at that time. In the case of the first planetary gear mechanism unit, the rotation of the carrier is output as the rotation of the output shaft fixed to the center of the carrier, and in the case of other planetary gear mechanism units, the rotation of the carrier is fixed to the center of the carrier. Output as rotation of the sun gear meshed with the planetary gear of the planetary gear mechanism unit.

  According to the first aspect of the present invention, the planetary gear of the first planetary gear mechanism unit arranged on the output side to which the load is most applied and the fixed internal gear meshing with the planetary gear are made of metal, thereby increasing the strength. Secured. Further, the planetary gear of the Nth (N is a natural number of 2 or more) planetary gear mechanism unit arranged on the lightly loaded drive side and the fixed internal gear meshing with the planetary gear are made of resin, thereby reducing the weight. Have gained. Since the drive side is lightly loaded, the strength is not required as much as the output side. For this reason, the planetary gear and the fixed internal gear can be made of resin.

  A second aspect of the present invention is the planetary gear of the second planetary gear mechanism unit according to the first aspect, wherein the N is 3 or more and is adjacent to the first planetary gear mechanism unit in the axial direction. Is made of metal. According to the second aspect of the present invention, the planetary gear of the second planetary gear mechanism unit, which requires the second strength next to the output side, is made of metal, so that higher strength can be secured.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the Nth internal gear is integrally formed with the frame. According to the third aspect of the present invention, a fixed internal gear having a structure in which a metal portion and a resin portion are integrated is obtained by a simplified process.

  According to the present invention, it is possible to obtain a planetary gear device that can be reduced in weight while ensuring necessary strength.

It is a disassembled perspective view of the planetary gear apparatus of embodiment. It is a disassembled perspective view of the frame part of embodiment.

(Constitution)
FIG. 1 is an exploded perspective view of the planetary gear device of the embodiment. FIG. 2 is an exploded perspective view of the frame portion of the embodiment. FIG. 2 shows an example of a version that does not include the flange portion 3e in FIG.

FIG. 1 shows a planetary gear device 1. The planetary gear device 1 includes a frame portion 2 that is a fixed member that does not rotate. The frame portion 2 is made of sintered metal, and as shown in FIG. 2, a metal sintered internal gear (first internal gear) 3 and a resin internal gear made of resin (Nth internal gear) 4. have. The sintered internal gear 3 and the resin internal gear 4 have a substantially cylindrical shape, and tooth portions 3a and 4a are provided on the inner peripheral surface thereof. Here, the tooth part 3a is comprised with the sintered metal, and the tooth part 4a is comprised with resin. The portion of the frame portion 2 of the inner sintered steel internal gear 3 is not provided, accommodating portion 3b for accommodating the resin internal gear 4 is provided. The accommodating portion 3b is formed by expanding the inner diameter. In the housing portion 3b, the resin internal gear 4 is housed and fixed without rotating relative to the sintered internal gear 3. Here, although the tooth parts 3a and 4a are different in material, they have the same shape.

  In this example, a resinous internal gear 4 is formed by injection molding using a resin made from a sintered internal gear 3 as an insert material, and the sintered internal gear 3 and the resin internal gear 4 are integrated. The structure is obtained. Examples of the structure that prevents the resin internal gear 4 from rotating with respect to the sintered internal gear 3 include a fixing structure using an adhesive and a structure that prevents rotation by a combination of a groove and a rail. Further, a structure in which the sintered internal gear 3 is separately manufactured and inserted into the separately prepared frame portion 2 is also possible.

  Three boss portions 3c are provided on the outer peripheral side of the frame portion 2, and each boss portion 3c is provided with a bolt hole 3d penetrating in the axial direction. The frame portion 2 is provided with three flange portions 3e, and each flange portion 3e is provided with a bolt hole 3f. Using the bolt hole 3d, the frame portion 2 is fixed to a driving device (not shown) such as a motor by a bolt.

  The four-stage planetary gear mechanism units 10, 20, 30, 40 are connected in series in an axially aligned state inside the frame portion 2 in a state where the resin internal gear 4 is accommodated in the accommodating portion 3 b. It has been. The planetary gear mechanism unit 10 is rotatable to an output shaft 11, a disk-shaped carrier 12 with the output shaft 11 fixed at the center, and equally spaced positions (120 ° angular positions) on the same circumference of the carrier 12. Three planetary gears 13 supported in a state are provided. The three planetary gears 13 are made of metal (sintered material) and mesh with the teeth 3 a inside the sintered internal gear 3.

  The planetary gear mechanism unit 20 includes a sun gear 21 disposed at a position coaxial with the output shaft 11, a disk-shaped carrier 22 fixed at the center of the sun gear 21, and equally spaced positions on the same circumference of the carrier 22. Three planetary gears 23 supported in a rotatable state (at an angular position of 120 °) are provided. The sun gear 21 is made of metal (sintered material), and the three planetary gears 23 are made of resin. The three planetary gears 23 mesh with the teeth 4 a inside the resinous internal gear 4. The sun gear 21 is located at the center of the three planetary gears 13 of the subsequent planetary gear mechanism unit 10 and meshes with each of the three planetary gears 13.

  The planetary gear mechanism unit 30 includes a sun gear 31 disposed coaxially with the output shaft 11, a disk-shaped carrier 32 fixed at the center of the sun gear 31, and equally spaced positions on the same circumference of the carrier 32. Three planetary gears 33 supported in a rotatable state (at an angular position of 120 °) are provided. The sun gear 31 is made of metal (sintered material), and the three planetary gears 33 are made of resin. The three planetary gears 33 mesh with the tooth portion 4 a inside the resinous internal gear 4. The sun gear 31 is located at the center of the three planetary gears 23 and meshes with each of the three planetary gears 23.

  The planetary gear mechanism unit 40 is freely rotatable to a sun gear 41, a disk-shaped carrier 42 having the sun gear 41 fixed at the center, and equally spaced positions (120 ° angular positions) on the same circumference of the carrier 42. Three planetary gears 43 supported in a state are provided. The sun gear 41 is made of metal (sintered material), and the three planetary gears 43 are made of resin. The three planetary gears 43 mesh with the teeth 4 a inside the resinous internal gear 4. The sun gear 41 is located at the center of the three planetary gears 33 and meshes with each of the three planetary gears 33.

  The sun gear 6 is disposed at the center position of the three planetary gears 43. The sun gear 6 meshes with each of the three planetary gears 43. The sun gear 6 is fixed to a drive shaft (rotary shaft) of a motor (not shown).

(Operation)
When a motor (not shown) rotates, the sun gear 6 rotates, and the planetary gear 43 meshed with the sun gear 6 rotates (rotates) accordingly. Since the planetary gear 43 meshes with the tooth portion 4a, when the planetary gear 43 rotates (spins), the planetary gear 43 revolves around the rotational axis of the sun gear 6 as a result. As the planetary gear 43 revolves, the carrier 42 rotates. Here, according to the principle of a general planetary gear mechanism, the rotation of the carrier 42 is decelerated with respect to the rotation of the sun gear 6.

  When the carrier 42 rotates, the sun gear 41 rotates, the planetary gear 33 meshed with the sun gear 41 rotates, and the carrier 32 rotates on the same principle as described above. At this time, further deceleration is performed.

  When the carrier 32 is rotated, the sun gear 31 is rotated, the planetary gear 23 meshed with the sun gear 31 is rotated, and the carrier 22 is rotated by the same principle as described above. At this time, further deceleration is performed.

  When the carrier 22 rotates, the sun gear 21 rotates, the planetary gear 13 meshed with the sun gear 21 rotates, and the carrier 12 to which the output shaft 11 is fixed rotates by the same principle as described above, and at the same time the output shaft 11 rotates. Rotate. At this time, further deceleration is performed. Thus, when the sun gear 6 is driven and rotated, deceleration is performed over four stages, and the output shaft 11 rotates while being decelerated. The final reduction ratio is the product of the reduction ratios of each stage, but the torque (load) applied to the gears of each stage increases as the speed is reduced, and becomes the maximum at the output shaft.

(Superiority)
As described above, the planetary gear device 1 includes the planetary gear mechanism unit 10 disposed on the output side and the planetary gear mechanism unit 40 disposed on the drive side, and each of the planetary gear mechanism units 10 to 40 includes: The planetary gears 13, 23, 33, 43 meshing with the fixed internal gears 3a, 4a and the sun gears 21, 31, 41, 6 and the planetary gears 13, 23, 33, 43 are rotatably supported and rotatable carriers. 12, 22, 32, 42, the planetary gear 13 and the tooth portion 3 a meshing with it are made of metal, and the other planetary gears 23, 33, 43 and the toothing portion 4 a meshing with it are made of resin.

  According to this structure, in the planetary gears of the four-stage planetary gear mechanism units 10 to 40, the planetary gear 13 on the most output side is most loaded, and the planetary gears 23 → 33 → 43 are hereinafter referred to. As the load is increased, the load is gradually reduced. This also applies to the fixed internal gears 3a and 4a that are in contact with the planetary gears 13 to 43. Therefore, in the present embodiment, the planetary gear 13 and the fixed internal gear 3a to which a strong load is applied are made of metal to ensure durability, and the planetary gears 23, 33, and 43 and the fixed internal gear 4a to which a relatively weak load is applied are made of resin. As a product, the part is lightened. In this way, the planetary gear device is reduced in weight while ensuring the necessary strength.

(Other)
Depending on the required strength, the second stage planetary gear 23 may be made of metal in addition to the first stage planetary gear 13. In this case, the fixed internal gear 3a is extended in the axial direction, and the fixed internal gear with which the planetary gear 23 meshes is made of metal. In this case, the weight increases but the durability increases as compared with the case where the planetary gear 23 and the fixed internal gear meshing with the planetary gear 23 are made of resin. And it is reduced in weight compared with the case where all the planetary gears and the fixed internal gears are made of metal.

  In the above illustration, an example in which the planetary gear mechanism unit has four stages is shown, but the present invention can be applied to a structure having two or more stages in which the output side is decelerated compared to the drive side. Further, in a configuration of three or more stages where the output side is decelerated compared to the drive side, the planetary gears and fixed internal gears in a plurality of stages counted from the output side are made of metal, and the remaining planetary gears and fixed internal gears are made of resin. By doing so, the balance between strength and weight reduction can be pursued. Further, the drive source is not limited to a motor. Further, the number of planetary gears in one stage is not limited to three, and two, four, or more cases are possible.

  The aspect of the present invention is not limited to the individual embodiments described above, and includes various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

  The present invention can be used for a planetary gear device.

  DESCRIPTION OF SYMBOLS 1 ... Planetary gear apparatus, 2 ... Frame part, 3 ... Sintered internal gear, 3a ... Tooth part, 3b ... Accommodating part, 3c ... Boss part, 3d ... Bolt hole, 3e ... Flange part, 3f ... Bolt hole, 4 ... resin internal gear, 4a ... tooth, 6 ... sun gear, 10 ... planetary gear mechanism unit, 11 ... output shaft, 12 ... carrier, 13 ... planetary gear, 20 ... planetary gear mechanism unit, 21 ... sun gear, 22 DESCRIPTION OF SYMBOLS ... Carrier, 23 ... Planetary gear, 30 ... Planetary gear mechanism unit, 31 ... Sun gear, 32 ... Carrier, 33 ... Planetary gear, 40 ... Planetary gear mechanism unit, 41 ... Sun gear, 42 ... Carrier, 43 ... Planetary gear.

Claims (3)

A planetary gear device comprising a plurality of planetary gear mechanism units connected in series from the drive side to the output side and decelerating the rotation transmitted from the drive side to the output side ,
Said plurality of planetary gear mechanisms unit, the N which is arranged on the first planetary gear mechanism unit and the drive-side arranged on the output side (N is a natural number of 2 or more) and a planetary gear mechanism unit,
Each of the plurality of planetary gear mechanism units rotatably supports the plurality of planetary gears meshed with a fixed internal gear and a sun gear disposed inside a cylindrical frame made of metal, and the plurality of planetary gears. A carrier rotatable inside the frame,
The planetary gear of the first planetary gear mechanism unit is made of metal,
The first internal gear meshing with the planetary gear of the first planetary gear mechanism unit of the fixed internal gear is made of metal,
The planetary gear of the Nth planetary gear mechanism unit is made of resin,
The Nth internal gear meshing with the planetary gear of the Nth planetary gear mechanism unit of the fixed internal gear is made of resin ;
The planetary gear device, wherein the Nth internal gear is fixed to the frame in a state of being housed in a housing portion formed by expanding the inner diameter of the inner circumferential portion of the frame . N is 3 or more,
2. The planetary gear device according to claim 1, wherein the planetary gear of the second planetary gear mechanism unit axially adjacent to the first planetary gear mechanism unit is made of metal. The planetary gear device according to claim 1 or 2, wherein the Nth internal gear is formed integrally with the frame.

Images