JP2017125539A - Planetary gear mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a structure in which an external force applied to an output shaft of a 3-K type planetary gear mechanism is hard to be transmitted to a power transmission member at an input side.SOLUTION: A planetary gear mechanism comprises: a sun gear 1 which is rotationally driven with respect to an input shaft 0; a plurality of planetary gear sets 4 which are constituted of a first planetary gear 2 and a second planetary gear 3; a carrier 6; a fixed inner gear 8 engaged with the first planetary gear 2; a movable inner gear 9 engaged with the second planetary gear 3; an output shaft 11; a housing 13; and a connecting rod 14 for transmitting the rotation of the movable inner gear 9 to the output shaft 11. The connecting rod 14 is inserted into a hole 16 which is formed at the output shaft 11, both ends of the connecting rod are engaged with the movable inner gear 9, and a clearance 19 in an axial direction is present between the connecting rod 14 and the output shaft 11.SELECTED DRAWING: Figure 1

Description

  According to the present invention, the external force applied to the output shaft is inexpensive and difficult to be transmitted to the power transmission member on the input side (component of the planetary gear mechanism disposed between the input shaft and the output shaft), and the power transmission member is deformed by the external force. The present invention relates to a planetary gear mechanism in which the torque is suppressed and stable torque transmission efficiency is maintained.

  One planetary gear mechanism is described in Patent Document 1 below. The planetary gear mechanism described in Patent Document 1 is referred to as a 3K type.

  FIG. 6 shows a specific example of the structure of the 3K type planetary gear mechanism that is easy to understand. The planetary gear mechanism of FIG. 6 includes a sun gear 1 fixed to an input shaft 0, a first planetary gear 2 meshing with the sun gear 1, and a second planetary gear 3 that rotates integrally with the first planetary gear 2. A plurality of planetary gear sets 4 arranged at equal pitches in the circumferential direction, and a carrier 6 to which a support shaft 5 that rotatably supports each of the planetary gear sets 4 is fixed.

  Further, a carrier bearing 7 that rotatably supports the carrier 6, a fixed internal gear 8 that meshes with the first planetary gear 2, and the second planetary gear 3 mesh with each other to be concentric with the center of rotation of the sun gear 1. A movable internal gear 9 supported so as to rotate on the circular orbit, an output shaft 11 which fixes the movable internal gear 9 and rotates integrally with the movable internal gear 9, and supports the output shaft 11. An oil seal 15 interposed between the pair of output shaft bearings 12, the housing 13 constituted by two members of the divided housings 13 a and 13 b, and the outer periphery of the output shaft 11 is combined.

JP2011-226518A

  The 3K type planetary gear mechanism of FIG. 6 is adopted in many transmissions because it is small and can realize a large speed ratio of reduction / acceleration, as described in the above-mentioned Patent Document 1. For this reason, there is a problem in that the deformation generated in the power transmission part increases, the meshing ratio of the gears decreases, and the torque transmission efficiency from the input part to the output part of the planetary gear mechanism significantly decreases. Cheap.

  Therefore, in order to improve the problem, the rigidity can be improved by increasing the size of the member including the bearing or adding an auxiliary bearing.

  For example, the planetary gear mechanism of Patent Document 1 supports the inner and outer peripheral sides of the carrier with bearings, and further, a movable internal gear (driven ring gear) supported on one of two carriers via a bearing. Bearings are also arranged between the outer periphery of the housing and the housing to ensure high rigidity, which is why the planetary gear mechanism has a large radial size.

  Further, in the planetary gear mechanism of FIG. 6, a bearing 7 is disposed auxiliary between the carrier 6 and the output shaft 11 in order to support the carrier 6 in a rotatable manner. Further, the bearing 7 has a small size, and the outer periphery of the carrier 6 is not supported by the bearing. Therefore, it is difficult to expect high rigidity, particularly high moment rigidity.

  In addition to this, the planetary gear mechanism of FIG. 6 incorporates a needle bearing 23 between the planetary gear set support shaft 5 and the planetary gear set 4 in order to support each planetary gear set 4 so as to be able to rotate. (This is a general technology and is also used in the planetary gear mechanism of Patent Document 1), which suppresses the backlash of the planetary gear set 4 and increases its rigidity, thereby requiring a simplified structure and a reduction in the number of parts. Difficult to meet.

  The present invention has been made in view of the above-mentioned present state of the art, and provides an inexpensive structure that makes it difficult for an external force applied to the output shaft of the 3K type planetary gear mechanism to be transmitted to the power transmission member on the input side. Is an issue.

  In order to solve the above problems, the present invention provides planetary gear mechanisms of the following first and second embodiments.

The planetary gear mechanism of the first form is
A sun gear that is driven by the input shaft and rotates;
A first planetary gear meshing with the sun gear and a second planetary gear arranged in parallel on the other end side of the first planetary gear and rotating integrally with the first planetary gear, are concentric with the axis of the sun gear. A plurality of planetary gear sets arranged at equal pitch on the circle,
A carrier that rotatably supports each of the planetary gear sets;
A fixed internal gear meshing with the first planetary gear;
A movable internal gear meshing with the second planetary gear;
An output shaft concentric with the input shaft, which is rotatably arranged on an extension of the input shaft;
A housing containing each of the components excluding a part of the input shaft and the output shaft;
A connecting rod that transmits the rotation of the movable internal gear to the output shaft;
The connecting rod is inserted into a hole provided in the output shaft, and both ends thereof are engaged with the movable internal gear, and between the connecting rod and the output shaft, or between the connecting rod and the movable internal gear. There is an axial gap in at least one of them.

Further, the planetary gear mechanism of the second form is configured such that the sun gear of the planetary gear mechanism of the first form is omitted and the carrier is directly driven to rotate by the input shaft.
The carrier that is driven by the input shaft and rotates;
A first planetary gear disposed on the circle concentric with the input shaft at an equal pitch and supported so as to be able to rotate on the carrier, and disposed in parallel on the other end side of the first planetary gear and integrated with the first planetary gear. A plurality of planetary gear sets composed of a second planetary gear rotating in the direction;
A fixed internal gear meshing with the first planetary gear;
A movable internal gear meshing with the second planetary gear;
An output shaft concentric with the input shaft, which is rotatably arranged on an extension of the input shaft;
A housing containing each of the components excluding a part of the input shaft and the output shaft;
A connecting rod that transmits the rotation of the movable internal gear to the output shaft;
The connecting rod is inserted into a hole provided in the output shaft, and both ends thereof are engaged with the movable internal gear, and between the connecting rod and the output shaft, or between the connecting rod and the movable internal gear. There is an axial gap in at least one of them.

The gap functions as a displacement absorbing portion that absorbs axial displacement of the output shaft, and a clearance larger than the axially possible movement allowance of the output shaft is preferable because of its high ability to absorb displacement.

  Here, “the axially possible movement allowance of the output shaft” is an axial displacement amount that is allowed when the output shaft receives an external force in the axial direction.

  The gap is preferably installed on both axial sides of the connecting rod. The gap can be created by making the hole provided in the output shaft into a long hole on the output shaft side.

Further, on the movable internal gear side, the movable internal gear can be provided with a hole or groove that allows the both ends of the connecting rod to enter, and the hole or groove can be made into a long hole or long groove that is long in the axial direction.

  An elastic support member made of soft rubber or the like can be disposed in the gap. The elastic support member is preferably one that surrounds the entire circumference of the connecting rod. The elastic support member surrounding the entire circumference of the connecting rod is provided with the gap in the entire outer periphery of the connecting rod and inserted into the gap.

  When the elastic support member is provided, the gap is filled with the elastic support member. In the present invention, the portion where the elastic support member is filled is also considered as the gap.

  In the planetary gear mechanism according to the present invention, when a force acting as an axial disturbance is applied to the output shaft, the force is released by the gap and the power transmission member on the input side (power transmission from the sun gear to the movable internal gear) The axial external force of the disturbance is hardly transmitted to the element.

  Thereby, the deformation | transformation of the input side power transmission member by an unnecessary load is suppressed, and the fall of the torque transmission efficiency resulting from the deformation | transformation is prevented.

It is sectional drawing which shows an example of the planetary gear mechanism of this invention. It is sectional drawing along the AA line of FIG. It is sectional drawing which shows the other example of the planetary gear mechanism of this invention. It is sectional drawing which shows the further another example of the planetary gear mechanism of this invention. It is sectional drawing which shows the further another example of the planetary gear mechanism of this invention. It is sectional drawing which shows an example of the conventional 3K type planetary gear mechanism.

  Embodiments of a planetary gear mechanism according to the present invention will be described below with reference to FIGS.

  FIG. 1 is a specific example of the planetary gear mechanism of the first embodiment. The planetary gear mechanism shown in FIG. 1 includes a plurality of planetary gear sets 4 including a sun gear 1 that is driven by an input shaft 0 to rotate, a first planetary gear 2 and a second planetary gear 3, and the planetary gear set 4. Each of which has a support shaft 5 that supports each of the shafts in a rotatable manner.

  Furthermore, the carrier 6, a carrier bearing 7 that supports the carrier 6 rotatably about the input shaft 0, a fixed internal gear 8 and a movable internal gear 9, a movable internal gear bearing 10, and an output shaft 11 And an output shaft bearing 12, a housing 13, a connecting rod 14, and an oil seal 15 interposed between the housing 13 and the output shaft 11.

The first planetary gear 2 meshes with the sun gear 1 and receives rotational force from the sun gear 1. The second planetary gear 3 is arranged in parallel on the other end side of the first planetary gear 2 and rotates integrally with the first planetary gear 2.

  The support shafts 5 are arranged at a constant pitch on a circle concentric with the axis of the sun gear 1 and fixed to the carrier 6.

  The carrier bearing 7 is interposed between the carrier 6 and the input shaft 0 and supports the carrier 6 so as to be rotatable about the input shaft 0.

  The fixed internal gear 8 meshes with the first planetary gear 2, while the movable internal gear 9 meshes with the second planetary gear 3 that rotates integrally with the first planetary gear 2.

  The movable internal gear bearing 10 supports the movable internal gear 9 so that it can rotate coaxially with the input shaft 0.

  The output shaft 11 is on an extension of the input shaft 0. The output shaft 11 is disposed concentrically with the input shaft 0 and is rotatably supported by the output shaft bearing 12.

  The housing 13 is a case constituted by two members, ie, divided housings 13a and 13b that enclose each of the components excluding a part of the input shaft 0 and the output shaft 11, and includes the movable internal gear bearing 10 and the output shaft. The bearing 13 is also supported by the housing 13.

The connecting rod 14 transmits the rotation of the movable internal gear 9 to the output shaft 11, and is inserted into a hole 16 provided in the output shaft 11, and a shaft hole 17 provided in the movable internal gear 9 at both ends. And is engaged with the movable internal gear 9.

  The shaft holes 17 are provided at two positions of the center symmetrical position of the movable internal gear 9, and both ends of the connecting rod 14 are inserted into the two shaft holes 17.

  Further, a screw plug 18 is screwed into the opening of the shaft hole 17 so as to have an appropriate gap between the connecting rod 14 and the connecting rod 14 by the screw plug 18 in the radial direction of the movable internal gear 9. Movement in the (longitudinal direction of self) is restricted.

  Between the connecting rod 14 and the output shaft 11, there is a gap 19 (see FIG. 2) that allows the connecting rod 14 to move in the axial direction.

  The gaps 19 of the planetary gear mechanism of FIG. 1 are created on both sides in the axial direction of the connecting rod 14 with the holes 16 being elongated holes in the axial direction. The clearance 19 is larger than the allowable movement allowance of the output shaft 11 in the axial direction.

  In the planetary gear mechanism of FIG. 1 configured as described above, when a force acting as an axial disturbance is applied to the output shaft 11, the connecting rod 14 of the force is formed by the elongated hole 16 formed in the output shaft 11. Therefore, almost no force acting as an axial disturbance is applied to the input-side power transmission member, and deformation of the input-side power transmission member due to the disturbance is suppressed.

3 and 4 are both modifications of the planetary gear mechanism of the first embodiment. In the planetary gear mechanism of FIG. 3, the gap 19 is provided not between the output shaft 11 and the connecting rod 14 but between the connecting rod 14 and the movable internal gear 9.

  The connecting rod 14 is fixed to the output shaft 11 through a round hole 16 provided in the output shaft 11. Further, a groove 20 that is long in the axial direction is formed at the rotational center symmetrical position of the movable internal gear 9, and both ends of the connecting rod 14 are fitted in the groove 20 so as to be movable in the axial direction. In addition, a gap 19 that allows relative movement of the connecting rod 14 in the axial direction is created.

  Even in this structure, the transmission of the force acting as an axial disturbance from the connecting rod 14 to the movable internal gear 9 is interrupted by the gap 19, and the deformation due to the disturbance of the input side power transmission member is suppressed.

  The planetary gear mechanism of FIG. 4 may be considered to be obtained by adding an elastic support member 21 made of soft rubber or the like to the planetary gear mechanism of FIG.

  The hole 16 formed in the output shaft 11 is a hole in which a gap is formed on both sides in the circumferential direction of the connecting rod 14 passed through the hole 16, and between the inner diameter surface of the hole 16 and the outer periphery of the connecting rod 14. A sleeve-like elastic support member 21 is incorporated in the housing.

  This is the difference from the planetary gear mechanism of FIG. 1, and other configurations are the same as the planetary gear mechanism of FIG. Therefore, the same elements are denoted by the same reference numerals and the description thereof is omitted.

In the planetary gear mechanism shown in FIG. 4, when a disturbance force is applied to the output shaft 11, the elastic support member 21 is compressed and the force is absorbed.

  In this structure, not only axial force but also circumferential force (moment force) is absorbed. As a result, axial and circumferential forces transmitted from the output shaft 11 to the input side power transmission member via the connecting rod 14 are attenuated, and deformation of the input side power transmission member due to the force is suppressed.

FIG. 5 is a specific example of the planetary gear mechanism of the second embodiment. The planetary gear mechanism of FIG.
A carrier 6 that is driven to rotate by the input shaft 0, a carrier bearing 7A that is mounted on the outer periphery of the carrier 6 and supports the carrier 6 so as to be rotatable about the input shaft 0, and concentric with the input shaft 0 The first planetary gear 2 that can be rotated at an equal pitch on the circle and the second planetary gear 3 that is arranged in parallel on the other end side of the first planetary gear 2 and rotates integrally with the first planetary gear 2. And a plurality of planetary gear sets 4 constituted by

  Further, a support shaft 5 fixed to the carrier 6 and rotatably holding each planetary gear set 4, a fixed internal gear 8 meshed with the first planetary gear 2, and a mesh with the second planetary gear 4. A movable internal gear 9 and a movable internal gear bearing 10 that supports the outer diameter side of the movable internal gear 9 so as to rotate coaxially with the input shaft 0 are provided.

  Further, an output shaft 11 concentric with the input shaft 0 that is rotatably arranged on the extension of the input shaft 0, an output shaft bearing 12 that rotatably supports the output shaft 11, and the input shaft 0 A housing 13 including two components, ie, divided housings 13a and 13b, which contain each of the constituent elements excluding a part of the output shaft 11, and support the movable internal gear bearing and the output shaft bearing, and the movable internal gear And a connecting rod 14 for transmitting 9 rotations to the output shaft 11.

The connecting rod 14 is fixed to the output shaft 11 through a hole 16 provided in the output shaft 11. Further, both ends of the connecting rod 14 are movably engaged with the movable internal gear 9.

The movable internal gear 9 is provided with a shaft hole 17 having a diameter larger than the diameter of the connecting rod 14 at the center symmetrical position, and a sleeve-like elastic support member 22 made of rubber or the like is incorporated in the shaft hole 17. The both ends of the connecting rod 14 are inserted and held in the holes of the elastic support member 22.

The planetary gear mechanism of FIG. 5 performs relative axial movement and circumferential relative movement of the connecting rod 14 with respect to the movable internal gear 9 between both ends of the connecting rod 14 and the inner diameter surface of the shaft hole 17 into which both ends are inserted. An allowable gap 19 exists, and the gap 19 is filled with the elastic support member 22.

  Therefore, according to the planetary gear mechanism of FIG. 5, as in the planetary gear mechanism of FIG. 4, the axial and circumferential forces transmitted from the output shaft 11 to the power transmission member on the input side via the connecting rod 14 are reduced. It is attenuated by the elastic support member 22, and the deformation of the input side power transmission member due to the force is suppressed.

  The planetary gear mechanism of the first form and the planetary gear mechanism of the second form are either of the structures that absorb the displacement of the output shaft 11 shown in FIGS. 1, 3, 4, and 5. Can be used in any combination.

  Further, the planetary gear mechanism of FIGS. 1, 3, and 4 further increases the rigidity by additionally installing a carrier bearing 7A employed in the planetary gear mechanism of FIG. 5 between the carrier 6 and the movable internal gear 9. be able to.

0 input shaft 1 sun gear 2 first planetary gear 3 second planetary gear 4 planetary gear set 5 support shaft 6 carrier 7, 7A carrier bearing 8 fixed internal gear 9 movable internal gear 10 movable internal gear bearing 11 output shaft 12 for output shaft Bearing 13 Housing 13a, 13b Divided housing 14 Connecting rod 15 Oil seal 16 Hole 17 Shaft hole 18 Screw plug 19 Clearance 20 Grooves 21, 22 in the axial direction Elastic support member 23 Needle bearing

Claims (7)

A sun gear (1) that is driven by the input shaft (0) and rotates;
A first planetary gear (2) meshing with the sun gear (1) and a second planetary gear arranged in parallel on the other end side of the first planetary gear (2) and rotating integrally with the first planetary gear (2) (3) and a plurality of planetary gear sets (4) arranged at an equal pitch on a circle concentric with the axis of the sun gear (1),
A carrier (6) that supports each planetary gear set (4) in a rotatable manner;
A fixed internal gear (8) meshing with the first planetary gear (2);
A movable internal gear (9) meshing with the second planetary gear (3);
An output shaft (11) concentric with the input shaft (0), which is rotatably arranged on an extension of the input shaft (0);
A housing (13) containing each of the components excluding a part of the input shaft (0) and the output shaft (11);
A connecting rod (14) for transmitting the rotation of the movable internal gear (9) to the output shaft (11);
The connecting rod (14) is inserted into a hole (16) provided in the output shaft (11), and both ends thereof are engaged with the movable internal gear (9). The connecting rod (14) and the output A planetary gear mechanism in which an axial gap (19) is present between the shaft (11) or at least one of the connecting rod (11) and the movable internal gear (9). A carrier (6) that is driven by the input shaft (0) and rotates;
The first planetary gear (2) disposed at an equal pitch on a circle concentric with the input shaft (0) and supported by the carrier (6) so as to be capable of rotating, and the other end side of the first planetary gear (2) A plurality of planetary gear sets (4) configured in parallel with the first planetary gear (2) and the second planetary gear (3) rotating together.
A fixed internal gear (8) meshing with the first planetary gear (2);
A movable internal gear (9) meshing with the second planetary gear (3);
An output shaft (11) concentric with the input shaft (0), which is rotatably arranged on an extension of the input shaft (0);
A housing (13) containing each of the components excluding a part of the input shaft (0) and the output shaft (11);
A connecting rod (14) for transmitting the rotation of the movable internal gear (9) to the output shaft (11);
The connecting rod (14) is inserted into a hole (16) provided in the output shaft (11), and both ends thereof are engaged with the movable internal gear (9). The connecting rod (14) and the output A planetary gear mechanism in which an axial gap (19) exists between at least one of the shaft (11) and the connecting rod (14) and the movable internal gear (9).   The said clearance gap (19) is provided between the said connection rod (14) and the said output shaft (11), The clearance gap (19) exists in the axial direction both sides of the said connection rod (14). The planetary gear mechanism according to 1 or 2.   The connecting rod (14) is fixed to the output shaft (11), and the gap (19) is provided between the connecting rod (14) and the movable internal gear (9) to connect the connecting rod (14). The planetary gear mechanism according to claim 1, wherein the planetary gear mechanism is present on both sides in the axial direction.   The gap (19) is provided between the connecting rod (14) and the output shaft (11), and the gap (19) exists in the entire outer periphery of the connecting rod (14), The planetary gear mechanism according to claim 1 or 2, wherein an elastic support member (21) surrounding the entire circumference of the connecting rod (14) is disposed in the gap (19).   The gap (19) is provided between the connecting rod (14) and the movable internal gear (9), and the gap (19) exists in the entire outer periphery of the connecting rod (14), The planetary gear mechanism according to claim 1 or 2, wherein an elastic support member (22) surrounding the entire circumference of the connecting rod (14) is disposed in the gap (19).   The planetary gear mechanism according to any one of claims 1 to 6, wherein an axial dimension of the gap (19) is set to be larger than a possible axial movement allowance of the output shaft (11).

Images