JP2008164086A - Differential type reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a differential type reduction gear with a normal combination of gears for producing a high reduction ratio. <P>SOLUTION: The differential type reduction gear comprises a differential gear mechanism 15, a reverse gear mechanism 17 and an output gear 16 in combination. The differential gear mechanism 15 consists of a differential part intermediate bevel gear 28 supported by a differential part intermediate shaft 25 and meshed with first and second input bevel gears 24, 26, and a connection shaft 39 connecting the differential part intermediate shaft 25 to the output gear 16. The reverse gear mechanism 17 consists of a reverse part input gear 31, a reverse part intermediate gear 32, and a reverse part output gear 33. The first input gear 22 is meshed with the reverse part input gear 31, and the reverse part output gear 33 is meshed with the second input gear 23. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a differential reduction gear used for a drive unit of various devices.

  A differential reducer manufactured by Harmonic Drive Co., Ltd. has been conventionally known as a differential reducer used in a drive unit of various devices and having a large reduction ratio (non-patent document). 1).

  This differential reduction gear is composed of an annular circular spline, an elliptical wave generator rotatably housed inside, and a flexible flex spline mounted on the outer periphery of the wave generator via a bearing. Become. The external teeth formed on the outer peripheral surface of the flexspline mesh with the internal teeth of the circular spline at two locations on both ends of the long diameter portion. When the circular spline is fixed and the wave generator is rotated, the flexspline rotates while being elastically deformed, and the meshing position with the inner teeth of the circular spline sequentially moves.

The differential reduction gear described above rotates at a reduced speed in the opposite direction by an amount less than the number of teeth of the circular spline (two teeth) per rotation of the wave generator. Generally, the movement of the flexspline is taken out as an output, and it is known that a high reduction ratio can be obtained.
URL http://www.hds.co.jp/principle/index.htm “Harmonic Drive (registered trademark) principle”

  In the above-described differential reduction gear, the flexspline to which the transmission torque is applied is a member that is required to have durability and also bendable, so that an inexpensive material such as a synthetic resin can be used. However, there is a problem that the production cost is high.

  Therefore, an object of the present invention is to provide a reduction gear that can be provided at low cost by using a material such as a synthetic resin and that can obtain a high reduction ratio.

  In order to solve the above-mentioned problems, the present invention has a basic structure of a differential reduction gear comprising a combination of a differential gear mechanism 15, a reverse gear mechanism 17, and an output gear 16, as shown in FIG. To do.

  The differential gear mechanism 15 includes a first input gear 22 composed of a first input spur gear 14 and a first input bevel gear 24, and a second input gear 23 composed of a second input spur gear 30 and a second input bevel gear 26. The differential intermediate bevel gear 28 that is supported by the differential intermediate shaft 25 between the first input bevel gear 24 and the second input bevel gear 26 and meshes with the first and second input bevel gears 24, 26 and the difference therebetween. It comprises a connecting means for connecting the moving part intermediate shaft 25 and the output gear 16.

  The reverse gear mechanism 17 includes a reverse rotation portion input gear 31, a reverse rotation portion intermediate gear 32, and a reverse rotation portion output gear 33. These at least two gears mesh with each other to reverse the input rotation and increase or decrease the speed. Can be output.

  Further, the first input gear 22 is meshed with the reverse rotation portion input gear 31, and the reverse rotation portion output gear 33 is meshed with the second input gear 23 of the differential gear mechanism 15.

  In the differential reduction gear of the present invention having the above-described configuration, the first input gear 22 and the second input gear 23 of the differential gear mechanism 15 rotate in opposite directions and with different rotation speeds. By inputting, the differential intermediate shaft 25 supporting the differential intermediate bevel gear 28 is decelerated and rotated according to the speed difference, and the output gear 16 connected to the differential intermediate shaft 25 is decelerated and rotated. The

  Input in the same rotational direction is applied directly from the input side to the first input gear 22 and the reverse rotation portion input gear 31 of the reverse rotation gear mechanism 17. In the reverse gear mechanism 17, the input rotation is reversed, and the speed is reduced or increased and applied to the second input gear 23 of the differential gear mechanism 17. As a result, the differential gear mechanism 15 causes the output gear 16 to output rotation corresponding to the difference in rotational speed.

  As described above, the differential reduction gear according to the present invention uses normal gear meshing, and unlike the above-described conventional example, there is no portion that is elastically deformed. In addition, since gears with normal specifications can be used, they can be provided at a low cost. Further, by making the rotational speed of the input from the reverse gear mechanism to the second input gear 23 of the differential gear mechanism as close as possible to the rotational speed of the first input gear 22, a high reduction ratio can be obtained.

  Embodiments of a differential speed reducer according to the present invention will be described below with reference to the accompanying drawings.

  The differential reduction gear according to the first embodiment shown in FIGS. 1 to 3 includes an operation part support shaft 12 and a reverse rotation part support shaft 13 fixed in parallel to the casing 11. A differential gear mechanism 15 and an output gear 16 are rotatably provided on the differential portion support shaft 12, and a reverse gear mechanism 17 is provided on the reverse portion support shaft 13. A motor 18 is fixed to the input side, and a drive gear 21 is attached to the motor shaft 19.

  In the differential gear mechanism 15, the first input gear 22 that rotates about the differential portion support shaft 12 and the second input gear 23 are arranged at symmetrical positions with the differential portion intermediate shaft 25 interposed therebetween. The first input gear 22 is formed as one component in which the first input bevel gear 24 and the first input spur gear 14 are integrated (see FIG. 2). The second input gear 23 is also formed as one part in which the second input bevel gear 26 and the second input spur gear 30 are integrated.

  As shown in FIG. 2, the differential portion intermediate shaft 25 is symmetrically disposed on the outer diameter surface of the boss portion 27 through which the differential portion support shaft 12 is inserted, and the differential portion intermediate shaft 25 with respect to the differential portion support shaft 12. It has an orthogonal axis. Differential portion intermediate bevel gears 28 and 28 that mesh with the first input bevel gear 24 and the second input bevel gear 26, respectively, are rotatably fitted to both ends of the differential portion intermediate shaft 25.

  Compared to the first input spur gear 14, the second input spur gear 30 is formed to have a slightly smaller diameter, and the number of teeth is reduced accordingly. 3A and 3B, the former diameter is indicated by L, and the latter diameter is indicated by L-α.

  The reverse gear mechanism 17 includes a reverse part input gear 31, a reverse part intermediate bevel gear 32 ′, and a reverse part output gear 33 that are meshed with each other in order. The reverse rotation portion input gear 31 is constituted by a single part including a reverse rotation portion input spur gear 31a and a reverse rotation portion input bevel gear 31b integrated on the inner surface thereof. The reverse rotation portion output gear 33 includes a reverse rotation portion output spur gear 33a and a reverse rotation portion output bevel gear 33b integrated on the inner surface of the reverse rotation portion output spur gear 33a. The reverse rotation portion intermediate bevel gear 32 'is meshed with the reverse rotation portion input bevel gear 31b and the reverse rotation portion output bevel gear 33b.

  The reverse rotation portion intermediate bevel gear 32 ′ is rotatably fitted to a reverse rotation portion intermediate shaft 34 having an axis perpendicular to the reverse rotation portion support shaft 13. A key 36 (see FIG. 2B) provided in the shaft hole of the boss portion 35 of the reverse rotation portion intermediate shaft 34 is fitted into the key groove 37 of the reverse rotation portion support shaft 13 so that it cannot rotate. The reverse rotation portion input gear 31 and the reverse rotation portion output gear 33 are rotatably fitted to the reverse rotation portion support shaft 13.

  The first input spur gear 14 meshes with the reverse rotation portion input spur gear 31 a and the reverse rotation portion output spur gear 33 a meshes with the second input spur gear 30. The reverse rotation portion output spur gear 33a has a slightly larger diameter than the reverse rotation portion input spur gear 31a (see L and L + α in FIGS. 3A and 3B), and meshes with the second input spur gear 30 to thereby The input from the 1-input spur gear 14 is reversed and accelerated to be input to the second input spur gear 30.

  The output gear 16 is provided with a cylindrical connecting shaft 39 (referred to as “connecting means” in claim 1) concentric with the shaft hole 38 on the inner surface thereof (see FIGS. 1 and 2A). ). The connecting shaft 39 is inserted into the shaft hole 41 of the second input gear 23 so as to be relatively rotatable. The engaging concave portion 42 provided at the tip of the connecting shaft 39 is fitted in the axial direction to the engaging convex portion 43 provided on the end surface of the boss portion 27 of the differential portion intermediate shaft 25 so as to be integrally rotatable. It has become. The connecting shaft 39 may be integrally provided on the end surface of the boss portion 27, and the tip portion may be engaged with the output gear 16.

  The differential reduction gear according to the first embodiment is configured as described above, and the operation thereof will be described next.

  The operation in which the rotation of the motor 18 is decelerated to the output gear 16 and output is as follows. That is, when the motor 18 and the drive gear 21 rotate in the direction of the constant arrow B in FIG. 1, the first input gear 22 meshed with the motor 18 and the drive gear 21 rotate in the direction A opposite to this, and the reverse rotation portion input gear 31 meshed with the first input gear 22. Rotates in the B direction. Further, the reverse output gear 33 rotates in the A direction and the second input gear 23 rotates in the B direction via the reverse intermediate bevel gear 32 '.

  In the reverse gear mechanism 17, as described above, rotation in the B direction is input to the reverse rotation portion input gear 31, and this rotation is rotated by three bevel gears (reverse rotation portion input bevel gear 31b, reverse rotation portion intermediate bevel gear 32 'and The reverse rotation portion output spur gear 33a rotates in the A direction by way of the reverse rotation portion output bevel gear 33b). That is, the rotation in the B direction on the input side is reversed to be output in the A direction, and the second input gear 23 is rotated in the B direction. The reverse gear mechanism 17 in this case has the convenience of being assembled on one differential support shaft 13.

  In the above, the operation when the motor 18 rotates in the B direction has been described. However, the same operation is performed when the motor 18 rotates in the A direction. This also applies to the following embodiments.

  Since the structure of the differential gear mechanism 15 of the differential reduction gear of the second embodiment shown in FIGS. 4 and 5 is the same as that of the first embodiment, the description thereof is omitted. Since the reverse gear mechanism 17 is different, the difference will be mainly described.

  In this case, the reverse rotation portion support shaft includes a rotatable reverse rotation portion first support shaft 13a and a reverse rotation portion second support shaft 13b fixed in parallel therewith. The reverse rotation portion input gear 31 and the reverse rotation portion intermediate gear 32 are attached to the reverse rotation portion first support shaft 13 a via the key structure 44. The reverse rotation portion output gear 33 is attached to the reverse rotation portion second support shaft 13b. The reverse rotation portion output gear 33 meshes with the reverse rotation portion intermediate gear 32 and the second input spur gear 30 (see FIG. 5).

  In the reverse gear mechanism 17 in this case, when the reverse rotation portion input gear 31 is rotated in the B direction, the reverse rotation portion intermediate gear 32 is rotated in the same direction, and the reverse rotation portion output gear 33 is rotated in the A direction. Thus, the same operation as that of the reverse gear mechanism 17 in the first embodiment is performed in that the rotation in the direction opposite to the input rotation direction is output. Further, by appropriately selecting the gear ratio, the speed can be increased / decreased as appropriate, thereby causing a speed difference between the first input gear 22 and the second input gear 23 of the differential gear mechanism 15, and the first embodiment. Similarly to the case, the decelerated rotation can be output to the output gear 16.

  In the case of the reversing gear mechanism 17 of the second embodiment, the cost can be reduced in that it can be constituted by a spur gear without using a bevel gear, but the reversing unit first support shaft 13a and the reversing unit Two support shafts of the two support shafts 13b are required.

  Since the structure of the differential gear mechanism 15 of the differential reduction gear of the third embodiment shown in FIGS. 6 and 7 is the same as that of the first and second embodiments, the description thereof is omitted. Since the reverse gear mechanism 17 is different, the difference will be mainly described.

  The reverse gear mechanism 17 in this case includes a reverse rotation portion support shaft 13, a reverse rotation portion input gear 31, a reverse rotation portion intermediate gear 32, and a reverse rotation portion output gear 33 attached to the reverse rotation portion support shaft 13.

  The reverse rotation portion intermediate gear 32 includes a sun gear 32a attached to the reverse rotation portion support shaft 13 and a plurality of planetary gears 32b disposed on the outer diameter surface of the sun gear 32a. The reverse rotation portion output gear 33 has a housing recess 45 at the center thereof, an inner tooth 46 (see FIG. 7) is formed on the inner diameter surface of the housing recess 45, and an outer tooth 47 is formed on the outer diameter surface. It consists of a double gear. The planetary gear 32 b is interposed between the sun gear 32 a and the internal teeth 46 of the reverse rotation portion output gear 33. The shaft 32 c of the planetary gear 32 b is supported by a carrier 48 fixed to the casing 11.

  As described above, the output gear 33 including the sun gear 32a, the planetary gear 32b, and the internal and external gears constituting the reverse rotation portion intermediate gear 32 constitutes a planetary gear mechanism in which the carrier 48 of the planetary gear 32b is fixed.

  In the reverse gear mechanism 17 in this case, when the reverse rotation portion input gear 31 is rotated in the B direction, the sun gear 32a of the reverse rotation intermediate gear 32 is rotated in the B direction (see FIG. 7), and the planetary gear 33b is rotated in the A direction. Rotate to Due to the rotation of the planetary gear 33b in the A direction, the reverse rotation portion output gear 33 is decelerated and rotated in the A direction.

  As a result, a speed difference is generated between the first input gear 22 and the second input gear 23 of the differential gear mechanism 15, and reduced rotation can be output to the output gear 16 as in the first and second embodiments. .

  In the case of the reversing gear mechanism 17 of the second embodiment, the cost can be reduced in that it can be constituted by a spur gear without using a bevel gear, but the reversing unit first support shaft 13a and the reversing unit Two support shafts of the two support shafts 13b, the planetary gear 32b, and the like are required.

Sectional view of Example 1 (A) Exploded perspective view of the differential gear mechanism portion as above, (b) Disassembled perspective view of the reverse gear mechanism portion as above. (A) is a sectional view of _X 1 -X ₁ line in FIG. 1, (b) is a sectional view of _X 2 -X ₂ line in FIG. 1 Sectional drawing of Example 2 Sectional view of the _X 3 -X ₃ line in FIG. 4 Sectional drawing of Example 3 Sectional view along line X ₄ -X ₄ in FIG.

Explanation of symbols

11 Casing 12 Differential support shaft 13 Reverse rotation support shaft 13a Reverse rotation portion first support shaft 13b Reverse rotation portion second support shaft 14 First input spur gear 15 Differential gear mechanism 16 Output gear 17 Reverse rotation gear mechanism 18 Motor 19 Motor shaft 21 drive gear 22 first input gear 23 second input gear 24 first input bevel gear 25 differential portion intermediate shaft 26 second input bevel gear 27 boss portion 28 differential portion intermediate bevel gear 30 second input spur gear 31 reverse rotation portion Input gear 31a Reverse rotation portion input spur gear 31b Reverse rotation portion input bevel gear 32 Reverse rotation portion intermediate gear 32 'Reverse rotation portion intermediate bevel gear 32a Sun gear 32b Planetary gear 33 Reverse rotation portion output gear 33a Reverse rotation portion output spur gear 33b Reverse rotation portion output bevel gear 34 Reversing portion intermediate shaft 35 Boss portion 36 Key 37 Key groove 38 Shaft hole 39 Connecting shaft 41 Shaft hole 42 Engaging recess 43 Engaging projection 44 Key structure 45 Storage recess 46 Internal teeth 47 External tooth 48 carrier

Claims (4)

In a differential reduction gear comprising a combination of a differential gear mechanism (15), a reverse gear mechanism (17) and an output gear (16),
The differential gear mechanism (15) includes a first input gear (22) comprising a first input spur gear (14) and a first input bevel gear (24), a second input spur gear (30) and a second input bevel. A second input gear (23) comprising a gear (26), and the first input bevel gear (24) and the second input bevel gear (26) supported by a differential intermediate shaft (25) between the first input bevel gear (24) and the second input bevel gear (26). A differential intermediate bevel gear (28) meshing with the second input bevel gears (24), (26) and a connecting means for connecting the differential intermediate shaft (25) and the output gear (16);
The reverse gear mechanism (17) includes a reverse rotation portion input gear (31), a reverse rotation portion intermediate gear (32), and a reverse rotation portion output gear (33). These at least two gears mesh with each other to input rotation. The first input gear (22) is meshed with the reverse rotation portion input gear (31), and the reverse rotation portion output gear (33) is the differential gear. A differential reduction gear characterized by being engaged with a second input gear (23) of a mechanism (15).   The reverse rotation portion input gear (31) of the reverse rotation gear mechanism (17) includes a reverse rotation portion input spur gear (31a) and a reverse rotation portion input bevel gear (31b) integrated therewith, and the reverse rotation portion output gear (33). Comprises a reverse rotation portion output spur gear (33a) and a reverse rotation portion output bevel gear (33b) integral therewith, and the reverse rotation portion intermediate gear (32) is a bevel gear (hereinafter referred to as "reverse rotation portion intermediate bevel gear (32 ')". The reversing portion intermediate bevel gear (32 ') is meshed with the reversing portion input bevel gear (31b) and the reversing portion output bevel gear (33b), and the first input spur gear (14). 2 is meshed with the reverse rotation portion input spur gear (31a), and the reverse rotation portion output spur gear (33a) is meshed with the second input spur gear (30). Differential reducer.   The reverse gear mechanism (17) has a reverse rotation portion first support shaft (13a) and a reverse rotation portion second support shaft (13b), and the reverse rotation portion first support shaft (13a) is rotatably supported. The reverse part input gear (31) and the reverse part intermediate gear (32) are attached to the first part support shaft (13a), and the reverse part intermediate gear (32) is attached to the reverse part second support shaft (13b). The differential reduction gear according to claim 1, wherein the differential reduction gear is meshed with the reverse rotation portion output gear (33).   The reverse gear mechanism (17) includes a reverse rotation portion support shaft (13), a reverse rotation portion input gear (31), a reverse rotation portion intermediate gear (32), and a reverse rotation portion output gear attached to the reverse rotation portion support shaft (13). (33), and the reverse rotation portion intermediate gear (32) is attached to the reverse rotation portion support shaft (13) and a plurality of planets arranged on the outer diameter surface of the sun gear (32a). The reversing part output gear (33) has a housing recess (45), and an inner tooth (46) is formed on the inner diameter surface of the housing recess (45), and the outer tooth is formed on the outer diameter surface. (47) is formed of both internal and external gears, and the planetary gear (32b) is interposed between the sun gear (32a) and the internal gear (46) of the reverse rotation portion output gear (33). The differential reduction gear according to claim 1, wherein

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