JP2006207650A - Differential gear unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a differential gear unit in which precise fit-holes for planetary gears are bored simply, and the whole cost can be reduced. <P>SOLUTION: The differential gear unit comprises a 1st sun gear 3 where a 1st shaft 1 is interlocked, a 2nd sun gear 4 where a 2nd shaft 2 is interlocked, 1st planetary gears 5 meshed respectively with the 1st sun gear 3, 2nd planetary gears 6 which are rotated together with the 1st planetary gears 5 and meshed with the 2nd sun gear 4, and a carrier 7 supporting the 1st and the 2nd planetary gears 5, 6. The carrier 7 has a 1st fit-hole 71 at the rotation center, and 2nd fit-holes 72, 72 at positions deviated from the rotation center, and allocated at equal intervals in the circumferential direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a differential gear device including a planetary gear.

A differential gear device including a planetary gear is used in a steering device for a vehicle. The differential gear device for a steering device includes a sun gear having a first shaft connected to a steering wheel, an internal gear coaxially rotatable around the outer periphery of the sun gear, the sun gear, Three planetary gears meshed with the internal gear, and a carrier that supports the planetary gear so as to freely rotate and rotate. By operating the steering wheel, the first shaft, the sun gear, the planetary gear, the carrier, and the internal gear Then, the second shaft is rotated, and the steering mechanism connected to the second shaft is operated (for example, Patent Document 1).
JP-A-61-122071

  By the way, the differential gear device including the planetary gear is processed with higher accuracy than a general gear such as a spur gear because the planetary gear revolves and rotates. However, high-precision machining is difficult to perform, and the cost of the planetary gear is relatively high. Accordingly, providing three or more planetary gears that are difficult to perform with high accuracy and are relatively high in cost increases the cost of the differential gear device. Further, in the carrier supporting the planetary gears, the insertion holes for the planetary gears are processed at equal intervals at three or more circumferential positions. However, the insertion holes can be processed with high accuracy at equal intervals. It is difficult and there is a problem that the cost of the differential gear device is relatively high.

  The present invention has been made in view of such circumstances, and a main object of the present invention is to provide a differential gear device capable of easily obtaining a high-precision insertion hole for a planetary gear and reducing the overall cost. There is to do.

  A differential gear device according to a first aspect of the present invention is a first and second sun gear that can freely rotate, a first planetary gear that meshes with the first sun gear, and a single planetary gear that rotates together with the first planetary gear. And a second planetary gear meshing with the second sun gear, and a carrier that supports the first and second planetary gears so that they can revolve and rotate freely, and has a fitting hole at the center of rotation. In the differential gear device, the carrier has insertion holes at positions equally spaced in the circumferential direction, and the planetary gear is supported by the two equally spaced insertion holes. To do.

  A differential gear device according to a second aspect of the present invention includes a rotatable sun gear, an internal gear rotatably disposed around the sun gear, and a planetary gear meshing with the sun gear and the internal gear. The differential gear device includes a carrier that supports the planetary gear so as to freely rotate and rotate. The carrier has fitting holes at positions that are equally spaced in the circumferential direction. The planetary gear is supported in the inserted hole.

  In the first invention and the second invention, since the three insertion holes are arranged on one line orthogonal to the rotation center line of the carrier, the three insertion holes are moved at the position where the tool is moved linearly. The insertion holes can be processed, and the high-precision insertion holes can be easily processed as compared with the case where the insertion holes are processed at three or more locations in the circumferential direction. Further, since the number of planetary gears supported by the carrier is two, the cost of the differential gear device can be reduced.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.
Embodiment 1
FIG. 1 is a cross-sectional view showing a configuration of a first embodiment of a differential gear device according to the present invention, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a side view of a carrier.

  The rotational transmission device includes a first shaft 1 and a second shaft 2 that are freely coaxially arranged, a first sun gear 3 in which the first shaft 1 is coaxially coupled, and a second shaft. The second sun gear 4 in which the two are interlocked on the same axis, the two first planetary gears 5 meshing with the first sun gear 3, and the first planetary gear 5 on the same axis. Two second planetary gears 6 that rotate and mesh with the second sun gear 4, a carrier 7 that supports the first and second planetary gears 5 and 6, and an outer peripheral portion of the carrier 7. In the middle of the first shaft 1, a differential electric motor 10 as an actuator that has an external tooth body 8, a first drive gear 9 that meshes with the teeth of the external tooth body 8, and rotates the carrier 7. A transmission gear 11 provided and a second drive gear 12 meshing with the transmission gear 11, and a reaction force in a direction opposite to the torque applied to the first shaft 1 Comprising an electric motor 13 of the reaction force as an actuator added to the first shaft 1.

  The 1st axis | shaft 1 and the 2nd axis | shaft 2 are rotatably supported by the stationary member via the bearing, and the 1st and 2nd sun gears 3 and 4 are facing coaxially. A torque sensor for detecting the torque applied to the first shaft 1 is provided around the outer periphery of the first shaft 1, and for differential and reaction forces based on the torque detected by the torque sensor. A control unit 14 that controls the drive circuits 10a and 13a of the electric motors 10 and 13 is provided.

  The first and second planetary gears 5 and 6 are tooth portions 5a and 6a that are spaced apart in the tooth width direction, and shaft portions 5b and 6b that protrude outward from the tooth portions 5a and 6a in the tooth width direction. Needle roller bearings 15 and 16 are externally fitted to the shaft portions 5b and 6b.

  The carrier 7 includes a disc-shaped first plate portion 7 a that is rotatably fitted and supported on an outer peripheral portion of the first shaft 1 via a needle roller bearing 17, and a needle roller on an outer peripheral portion of the second shaft 2. A disk-shaped second plate portion 7b that is rotatably fitted and supported via a bearing 18, and a connecting cylinder that connects the outer peripheral portions of the first plate portion 7a and the second plate portion 7b with connecting means such as bolts. An annular external tooth body 8 having a plurality of teeth is integrally provided on the outer peripheral portion of the connecting cylinder portion 7c.

  A first insertion hole 71 is provided in the rotation center portion of the first plate portion 7a and the second plate portion 7b. The first insertion hole 71 is deviated from the rotation center portion, and two second positions are arranged in the circumferential direction. Two insertion holes 72, 72 are provided. That is, the first and second insertion holes 71, 72, 72 are arranged in parallel on one line X orthogonal to the rotation center line of the carrier 7, and the first insertion hole 71 has a needle roller bearing. The first shaft 1 is fitted through 17, and the shaft portions 5 b of the first and second planetary gears 5, 6 are inserted into the second fitting holes 72, 72 via needle roller bearings 15, 16. 6b is inserted.

FIG. 4 is an explanatory view showing a method of processing a carrier of the differential gear device according to the present invention. As described above, the processing of the first plate portion 7a and the second plate portion 7b of the carrier 7 in which the first and second insertion holes 71, 72, 72 are provided on one line orthogonal to the rotation center line is as follows. For example, the following first, second, and third methods are used.
First method. The first and second insertion holes 71, 72, 72 are pressed by moving the insertion hole processing tool such as a punch up and down / moving linearly between three positions on one line of the circular metal plate. In this case, the insertion holes 71, 72, and 72 can be easily positioned and can be easily processed as compared with the case of processing the insertion holes that are equally distributed in three or more circumferential directions.
Second method. The first and second insertion holes 71, 72, 72 are pressed at a time by moving up and down three insertion hole processing tools such as punches on a circular metal plate. In this case, the insertion holes 71 and 72 having different inner diameters can be easily processed with high accuracy.
Third method. After processing the first and second insertion holes 71, 72, 72 on the relatively thin circular metal plate by the first or second method, a plurality of perforated circular metal plates are converted into the first and second holes. Are laminated so that the insertion holes 71, 72, 72 are concentric, and the laminated circular metal plates are integrally coupled by a coupling means such as caulking. In this case, since the fitting holes 71, 72, 72 can be pressed into a relatively thin circular metal plate, the processing accuracy of the fitting holes 71, 72, 72 can be increased.

  The differential gear device configured as described above is mainly used in a vehicle steering device. In this steering apparatus, a steering wheel is coupled to a first shaft 1, a second shaft 2 has a pinion and rack teeth meshing with the pinion, and a steered shaft capable of moving in the axial length direction thereof. The pinion of the steering mechanism provided with is interlocked and connected so that the steered wheels supported at both ends of the steered shaft can be steered.

  The steering device configured as described above passes through the first sun gear 3, the first and second planetary gears 5 and 6, and the second sun gear 4 when the steering wheel rotates the first shaft 1. The second shaft 2 rotates at the same speed as the first shaft 1. Further, when the differential electric motor 10 is driven by a command signal output from the control unit 14 to the drive circuit 10a, the carrier 7 rotates via the drive gear 9 and the external tooth body 8, and the first and first The second shaft 2 rotates at a higher speed through the second planetary gears 5 and 6 and the second sun gear 4. When the torque applied to the first shaft 1 is reduced by the accelerated rotation of the second shaft 2, the reaction force electric motor 13 is driven by the command signal output from the control unit 14 to the drive circuit 13a, and the first shaft 1 is driven. A reaction force in the direction opposite to the rotation direction of the shaft 1 is applied to the first shaft 1, and the torque applied to the first shaft 1 can be maintained at a predetermined value.

Embodiment 2
FIG. 5 is a schematic diagram showing the configuration of the second embodiment of the differential gear device according to the present invention. The differential gear device includes a first shaft 1 and a second shaft 2 that are rotatably arranged on the same axis, a sun gear 20 that is rotatably fitted to the second shaft 2, and the sun gear 20. , A planetary gear 22 which meshes with the sun gear 20 and the internal gear 21, and the planetary gear 22. Is supported, and the second shaft 2 is coaxially interlocked and linked, and a differential electric motor 24 serving as an actuator disposed around the outer periphery of the second shaft 2. A cylindrical rotor 24 a is connected to the sun gear 20 coaxially.

  In the second embodiment, the internal gear 21 has a bottomed cylindrical shape having teeth on the inner periphery, and the first shaft 1 is coupled to the center of the bottom. The sun gear 20 is formed integrally with a rotor 24a as a movable part, a permanent magnet 24b is provided on the outer periphery of the rotor 24a, and a stator 24c is provided around the outer periphery of the permanent magnet 24b. Yes.

The carrier 23 has a disk shape, and the insertion holes 72 and 72 are equally arranged at two positions deviated from the rotation center. In other words, the two insertion holes 72 and 72 are arranged on one line orthogonal to the rotation center line. 72 is provided, and the planetary gears 22 and 22 are rotatably supported in the insertion holes 72 and 72. The insertion holes 72 and 72 are processed in the same manner as the first, second, and third methods in the first embodiment.
The planetary gear 22 has a tooth part 22a and a shaft part 22b protruding from one side of the tooth part 22a. The shaft part 22b is cantilevered into the insertion hole 72 via the needle roller bearing 15. It is supported by.

  In the second embodiment, by rotating the first shaft 1, the second shaft 2 rotates at a reduced speed via the internal gear 21, the planetary gear 22 and the carrier 23. Further, when the differential electric motor 24 is driven by a command signal output from the control unit 14 to the drive circuit, the second shaft 2 rotates at a higher speed via the sun gear 20, the planetary gear 22 and the carrier 23. .

  Although the electric motor for reaction force is not shown in the second embodiment, a transmission gear is provided in the middle of the first shaft 1 as in the first embodiment, and a drive gear that meshes with the transmission gear is provided. It is good also as a structure which provided the electric motor for reaction force which has and has the reaction force of the opposite direction to the torque added to the 1st axis | shaft 1 to the 1st axis | shaft 1. Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.

  In the embodiment described above, the electric motors 10 and 13 are used as the differential and reaction force actuators. However, the differential and reaction force actuators are not specified as electric motors.

  In the embodiment described above, the differential and reaction force electric motors (actuators) 10 and 13 are provided. However, the reaction force electric motor (actuator) 13 is not necessarily required.

  In the first embodiment, the differential electric motor 10 rotates the carrier 7. However, for example, the electric motor 10 may directly rotate the second shaft 2.

  In the second embodiment, the internal gear 21 is linked to the first shaft 1, the carrier 23 is linked to the second shaft 2, and the differential electric motor 24 rotates the sun gear 20. In addition, in FIG. 5, the first shaft 1 may include the sun gear 20, the carrier 23 may be interlocked with the rotor 24 a of the electric motor 24, and the carrier 23 may be rotated by the electric motor 24. 5, the carrier 23 may be linked to the first shaft 1, the internal gear 21 may be linked to the rotor 24 a of the electric motor 24, and the second shaft 2 may include the sun gear 20. 1, the first shaft 1 may include the sun gear 20, the internal gear 21 may be interlocked with the rotor 24 a of the electric motor 24, and the second shaft 2 may include the carrier 23.

It is sectional drawing which shows the structure of Embodiment 1 of the differential gear apparatus which concerns on this invention. It is sectional drawing of the II-II line of FIG. It is a side view of the carrier of the differential gear device according to the present invention. It is explanatory drawing which shows the processing method of the carrier of the differential gear apparatus which concerns on this invention. It is a schematic diagram which shows the structure of Embodiment 2 of the differential gear apparatus which concerns on this invention.

Explanation of symbols

3 First Sun Gear 4 Second Sun Gear 5 First Planetary Gear 6 Second Planetary Gear 7 Carrier 71 First Insertion Hole 72 Second Insertion Hole 20 Sun Gear 21 Internal Gear 22 Planetary Gear 23 Carrier

Claims (2)

  First and second sun gears that can freely rotate, a first planetary gear meshing with the first sun gear, and rotating integrally with the first planetary gear and meshing with the second sun gear In the differential gear device including a second planetary gear and a carrier that supports the first and second planetary gears so that they can freely rotate and rotate, and has a fitting hole at a center of rotation thereof, the carrier includes: A differential gear device characterized by having insertion holes at positions equally spaced in the circumferential direction, and the planetary gears being supported by the two equally spaced insertion holes. A freely rotatable sun gear, an internal gear rotatably disposed around the sun gear, a planetary gear meshing with the sun gear and the internal gear, and the planetary gear can freely rotate and rotate. In the differential gear device including the carrier to be supported, the carrier has insertion holes at positions equally spaced in the circumferential direction, and the planetary gear is supported by the two equally spaced insertion holes. A differential gear device characterized by comprising:

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