JPH10153244A - Planetary roller-type speed reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planetary roller-type speed reduction gear capable of being smoothly operated without generating problems that bearing noise is generated and rotational resistance of a sun roller is increased, regardless of dimensional precision and assembling precision of a casing in which the planetary roller speed reduction gear is to be housed. SOLUTION: In a planetary roller-type speed reduction gear 15, a sun roller 18 is rotatably supported on the center part of a ring roller 17 regulated from being rotated, a plurality of planetary rollers 19 are interposed between the inner peripheral surface of the ring roller 17 and the outer peripheral surface of the sun roller 18, a speed reduction carrier 21 for supporting the planetary rollers 19 is so provided as to be coaxially and relatively rotated with the sun roller 18, a primary drive gear 33 is rotatably and integrally fixed to the speed reduction carrier 21, only one end of the sun roller 18 is supported by a bearing 28, the intermediate part of the sun roller 18 is supported by the contact to the planetary rollers 19, and the speed reduction carrier 21 is supported to the outer periphery of the other end of the sun gear 18 through a bearing 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary roller reduction device which is provided coaxially with a main shaft of an electric motor or the like, and transmits the rotation of the main shaft at a reduced speed.

[0002]

2. Description of the Related Art FIG. 5 is a cross-sectional view showing an example of a conventionally used planetary roller reduction device. In this planetary roller reduction device 101, a sun roller 103 is rotatably supported at the center of a ring roller 102 whose rotation is regulated, and a plurality of sun rollers 103 are provided between an inner peripheral surface of the ring roller 102 and an outer peripheral surface of the sun roller 103. While a planetary roller 104 is interposed, a deceleration carrier 106 provided coaxially and relatively rotatably with the sun roller 103 via a bearing 105 has a roller shaft 107 for rotatably supporting the planetary roller 104 and a primary drive. A gear 108 is provided integrally with the rotation. The planetary roller 104 is supported by a roller shaft 107 via a bearing 109.

The sun roller 103 has bearings 110 at both ends.
The main shaft 113 of the electric motor 112 is integrally connected to one end of the electric motor 112 by a spline connection or the like.
Communicated to 103. The bearings 110 and 111 are fixed to a casing 114 in which the planetary roller reduction device 101 and the electric motor 112 are housed.

[0004] The casing 114 can be divided into a casing body 114a and a casing cover 114b. A bearing 110 is provided on the casing body 114a side.
A bearing 111 is provided on the 4b side. The ring roller 102 of the planetary roller reduction device 101 is fixed to one side of the casing body 114a by bolts 116, and the electric motor 112 is fixed to the other side of the casing body 114a by bolts 117.

When the main shaft 113 and the sun roller 103 rotate, each planetary roller 104 revolves around the sun roller 103 while rotating between the fixed ring roller 102 and the rotating sun roller 103. 106 and the primary drive gear 108 are decelerated and rotated,
The power of the electric motor 112 is reduced and transmitted to the driven gear 117 meshing with the primary drive gear 108.

[0006]

However, as described above, the bearings 110 and 111 for supporting both ends of the sun roller 103 are provided separately in the casing body 114a and the casing cover 114b of the casing 114. Therefore, depending on the dimensional accuracy and assembling accuracy of the casing 114, the axial center of the bearing 110 and the bearing 111 may be shifted. In this case, intermittent contact occurs in each of the bearings 105, 109, 110, and 111, and as a result, bearing noise easily occurs.

[0007] Such noise is transmitted to the casing cover 114b via the bearing 111 and resonates from the casing cover 114b to the outside, so that it is extremely annoying and also shortens the life of the entire planetary roller reduction device 101. . Also, there is a large difference in the volume of the noise, and in some cases, a very loud noise is generated, and there is a case where the assembly must be repeated.

Further, since the rotational resistance of the sun roller 103 is significantly increased due to the deviation of the axis between the bearing 110 and the bearing 111, the load of the electric motor 112 is increased and the power consumption rate is increased. .

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the bearing noise is generated and the sun roller is not affected irrespective of the dimensional accuracy and the assembly accuracy of the casing accommodating the planetary roller reduction device. It is an object of the present invention to provide a planetary roller speed reducer that can operate smoothly without causing a problem such as an increase in rotational resistance.

[0010]

In order to achieve the above object, a planetary roller speed reducer according to the present invention has a sun roller rotatably supported at the center of a ring roller whose rotation is restricted. A plurality of planetary rollers are interposed between the inner peripheral surface and the outer peripheral surface of the sun roller, and a reduction carrier that supports these planetary rollers is provided coaxially and relatively rotatable with the sun roller. In a planetary roller speed reducer in which the primary drive gear is fixed integrally with the rotation, only one end of the sun roller is supported by bearings, the middle part of the sun roller is supported by contact with the planetary roller, and the outer periphery of the other end of the sun roller The deceleration carrier is supported via a bearing.

According to the present invention, since the bearing is provided only at one end of the sun roller, there is a concern that problems such as generation of bearing noise due to misalignment of the axes of the plurality of bearings and increase in rotational resistance of the sun roller occur. Disappears.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a drive assist device mounted on a bicycle body and configured to assist pedal depression force by a drive assist force of an electric motor provided inside the bicycle. It is the direction of travel.

A metal casing 2 forming the outer shell of the drive assist device 1 can be divided into a casing main body 2a and a casing cover 2b, and is assembled with through bolts 3. A crankshaft 4 extending in the vehicle width direction is rotatably supported at a rear portion inside the casing 2. Cranks 5L and 5R are fixed to both ends of the crankshaft 4 with bolts 6. An intermediate device 7 is axially mounted at an intermediate portion of.

The right end of the resultant device 7 projects rightward from the casing 2 and has a drive sprocket 8
Is provided. A chain 9 is wound between the drive sprocket 8 and a driven sprocket (not shown) provided on the rear wheel of the bicycle.

On the other hand, the electric motor 11 described above is built in a rear portion in the casing 2. This electric motor 11
Is fixed to the right side of an inner wall 2c formed on the casing body 2a side with a stud bolt 12 and a nut 13, and is installed so that its main shaft 14 is parallel to the crankshaft 4. A planetary roller reduction device 15 according to the present invention is installed on the opposite side of the electric motor 11 with the inner wall portion 2c interposed therebetween.

FIG. 2 is an enlarged cross-sectional view of the planetary roller reduction device 15 showing one embodiment of the present invention. FIGS. 3 and 4 show planetary gears taken along lines III-III and IV-IV of FIG. 2, respectively. FIG. 2 is a longitudinal sectional view of a roller reduction device 15.

The planetary roller speed reducer 15 has an inner wall 2
a ring roller 17 fixed to the left side surface of the ring c with three bolts 16 and restricted in rotation, a sun roller 18 rotatably supported at the center of the ring roller 17, and an inner peripheral surface of the ring roller 17 And four planetary rollers 19 that are slightly press-fitted between the outer peripheral surfaces of the sun roller 18 and a deceleration carrier 21 that is provided coaxially and relatively rotatable with respect to the sun roller 18. ing.

Four roller shafts 22 parallel to the sun roller 18 are fixed to the deceleration carrier 21. Each of the planetary rollers 19 is rotatably supported by these roller shafts 22 via a bearing 23. . Note that cover plates 24 and 25 are mounted on both side surfaces of the ring roller 17 and the planetary roller 19, respectively.

A joint member 26 is fixed to the end of the sun roller 18 on the side of the electric motor 11 by press fitting or the like so as to rotate integrally with the main shaft 14 of the electric motor 11 by spline coupling or the like. Be linked.
The joint member 26 may be formed integrally with the sun roller 18.

The sun roller 18 has only one end supported by a bearing. In other words, only the end (the joint member 26) of the sun roller 18 on the side of the electric motor 11 is supported by the bearing 28 provided on the inner wall 2c of the casing 2, and the intermediate portion of the sun roller 18 is four pieces. Planetary rollers of 19
Supported by contact with. A deceleration carrier 21 is rotatably supported on the outer periphery of the other end of the sun roller 18 via a bearing 29, and is prevented from falling off by a washer 30 and a circlip 31. Further, a primary drive gear 33 is integrally formed on the outer periphery of the reduction carrier 21.

An intermediate shaft 34 is rotatably supported between the sun roller 18 of the planetary roller reduction device 15 and the crankshaft 4. The intermediate shaft 34 has a large-diameter primary driven gear 35 and a small diameter. A secondary drive gear 36 is provided. The primary driven gear 35 is the primary drive gear 33
The secondary drive gear 36 meshes with a secondary driven gear 37 provided on the left side of the resultant device 7.

When the main shaft 14 of the electric motor 11 rotates, the sun roller 18 of the planetary roller reduction device 15 rotates integrally, and each planetary roller 19 rotates between the fixed ring roller 17 and the rotating sun roller 18. While revolving around the sun roller 18, the deceleration carrier 21 and the primary drive gear 33 are decelerated and rotated.

The rotation of the primary drive gear 33 is transmitted to the secondary driven gear 37 through the primary driven gear 35 and the secondary drive gear 36. Thus, the electric motor
The rotational force (drive assist force) of the main shaft 14 is reduced to three stages by the planetary roller reduction device 15 and the four gears 33, 35, 36, and 37, and then input to the resultant device 7.

As shown by an arrow in FIG.
11, the main shaft 14, the sun roller 18, the reduction carrier 21, and the primary drive gear 33 rotate in the direction A, the intermediate shaft 34, the primary driven gear 35, and the secondary drive gear 36 rotate in the direction indicated by the arrow B, and the secondary driven gear 37 rotates in the direction indicated by arrow C.

On the other hand, pedals (not shown) are attached to the ends of the cranks 5L, 5R fixed to both ends of the crankshaft 4, and when the pedals are depressed by a bicycle occupant, the crankshaft 4 also moves in the direction of arrow C Is driven to rotate. The resultant device 7 combines the rotational force (pedal force) of the crankshaft 4 and the driving assist force of the electric motor 11 in a well-balanced manner, and outputs the resultant to the drive sprocket 8 to drive the rear wheel of the bicycle. Have been.

The planetary roller reduction device according to the present embodiment
15, as described above, only the end of the sun roller 18 on the electric motor 11 side is supported by the bearing 28, and the middle part of the sun roller 18 is supported by contact with the four planetary rollers 19, On the outer periphery of the other end of the roller 18, a deceleration carrier 21 is supported via a bearing 29.

For this reason, bearings are provided at both ends of the sun roller 18 as in a conventional planetary roller speed reducer, and these bearings are provided on the casing body 2a of the casing 2.
And the casing cover 2b, the bearing 28 of the sun roller 18 and the planetary roller even if the casing 2 has poor dimensional accuracy and assembly accuracy.
A situation where the axis of the bearing 23 of the bearing 19 and the bearing 29 of the reduction carrier 21 are displaced from each other cannot occur.

Therefore, regardless of the accuracy of the casing 2, etc.
Planetary roller speed reducer without problems such as bearing noise and increased rotation resistance of sun roller 18.
15 can be operated smoothly.

[0029]

As described above, in the planetary roller reduction device according to the present invention, only one end of the sun roller is supported by a bearing, and an intermediate portion of the sun roller is supported by contact with the planetary roller. In order to feature that the reduction carrier is supported on the outer circumference of the other end of the roller via a bearing,
Regardless of the dimensional accuracy, assembly accuracy, etc. of the casing in which the planetary roller reduction gear is housed, there is no concern that problems such as generation of bearing noise due to misalignment of the shaft centers of multiple bearings and increase in rotational resistance of the sun roller will occur. It can work smoothly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a drive assist device incorporating a planetary roller speed reducer according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a planetary roller reduction device showing one embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of the planetary roller reduction device taken along the line III-III of FIG.

4 is a longitudinal sectional view of the planetary roller reduction device taken along the line IV-IV in FIG.

FIG. 5 is a cross-sectional view of a planetary roller reduction device showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive auxiliary device 7 Synthetic device 11 Electric motor 15 Planetary roller reduction device 17 Ring roller 18 Sun roller 19 Planetary roller 21 Reduction carrier 22 Roller shaft 33 Primary drive gear 23, 28, 29 Bearing

Continued on front page (72) Inventor Kohei Tomita 300 Takatsukacho, Hamamatsu-shi, Shizuoka Suzuki Co., Ltd.

Claims (1)

[Claims] A sun roller is rotatably supported at the center of a ring roller whose rotation is regulated, and a plurality of planetary rollers are provided between an inner peripheral surface of the ring roller and an outer peripheral surface of the sun roller. A planetary gear 19 is interposed, and a reduction carrier 21 that supports these planetary rollers 19 is provided coaxially and relatively rotatably with the sun roller 18, and a primary drive gear 33 is fixed to the reduction carrier 21 so as to rotate integrally therewith. In roller reduction gear, only one end of sun roller 18 is bearing
It is supported by 28, and the middle part of the sun roller 18 is the planetary roller 19
A planetary roller reduction device 15 characterized in that the planetary roller reduction device 15 is supported by contact with the sun roller 18 and the reduction roller carrier 21 is supported on the outer periphery of the other end of the sun roller 18 via a bearing 29.