JPH11303957A - Planetary roller-type transmission and drive connection structure for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent noise and vibration from being generated caused by drive- connection of a sun roller as an input member and a transmission shaft, in a planetary roller-type transmission. SOLUTION: In the planetary roller-type transmission, a sun roller 31 is formed into a cylindrical shape, and a cylindrical elastic member 30 is press- fitted in the inner peripheral surface 31a. A fitting hole 30a of the elastic member 30 is taken as a torque transmission surface, a rotary shaft 2a of a motor is press-fitted in it and drive-connected. Clearances between the elastic member 30 and the sun roller 31 and between the elastic member 30 and the rotary shaft 2a are eliminated. Therefore, inclination and eccentricity between the sun roller 31 and the rotary shaft 2a can be absorbed by the elastic member 30, moreover, vibration and noise can be prevented. Therefore, assembling costs and costs of parts can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a planetary roller type transmission. In particular, it relates to a drive coupling structure for inputting and outputting rotational force to the sun roller.

[0002]

2. Description of the Related Art For example, in a planetary roller type transmission, a sun roller as an input member, a plurality of planetary rollers revolving while rolling on the outer peripheral surface of the sun roller, and a plurality of planetary rollers are inscribed. It has a fixed wheel including a track and a carrier as an output member that rotatably supports a plurality of planetary rollers. The sun roller and the planetary roller, and the planetary roller and the fixed wheel, perform a rolling motion while reliably contacting each other in a state where the pressing force is applied without play between the sun roller and the planetary roller, thereby transmitting the driving force. Like that. Therefore, in the planetary roller type transmission, quieter driving force transmission can be realized as compared with a gear mechanism or the like.

When a planetary roller transmission is used, the sun roller is drivingly connected to an output shaft of a motor as a driving source. For example, the sun roller and the output shaft are connected to each other by a spline structure or a press-fitting structure between a boss hole of the sun roller and the output shaft, and the rigid members of the hole member and the shaft member are usually fastened.

[0004]

By the way, it is assumed that when the sun roller and the output shaft are connected to each other and rotate, there is a positional deviation such as eccentricity or inclination between the sun roller and the output shaft. However, the following noise and vibration may be a concern.

In the spline structure, since there is a gap between the shaft and the hole, noise is generated as a result of the sound of the shaft and the hole colliding or rubbing in the gap due to the above-described positional deviation and uneven rotation. .

[0006] In the press-fitting structure, the gap between the shaft and the hole can be eliminated to prevent noise in the spline structure. On the other hand, the sun roller is rotatably supported without play in the radial direction as described above and is press-fitted. Moreover, since a fluctuating force acts, vibration occurs in the planetary roller type transmission.

In order to prevent such vibrations and noises, the output shaft and the sun roller are assembled by connecting the output shaft and the sun roller with high precision so as not to cause the above-mentioned positional deviation. Cost was high. In addition,
Components for realizing high-precision assembly required high component accuracy and were expensive. As a result, the manufacturing cost of the planetary roller type transmission has been increased.

An object of the present invention is to solve the above-mentioned technical problems and to provide a planetary roller type transmission which can prevent noise and vibration at low cost, and a drive connection structure therefor.

[0009]

According to a first aspect of the present invention, there is provided a drive connection structure in which a plurality of planetary rollers held by a carrier are interposed between an outer ring member and a sun roller. In the planetary roller type transmission, a driving connection structure for drivingly connecting the sun roller and the transmission shaft, wherein the sun roller is formed of a cylindrical body, and a cylindrical elastic member is transmitted to an inner peripheral surface of the cylindrical body by torque transmission. The elastic member is provided so as to be capable of transmitting torque to the transmission shaft.

According to this configuration, the following operations are provided.
That is, when the transmission shaft is arranged in the cylinder of the elastic member, the transmission shaft and the sun roller are drivingly connected to each other and can rotate to transmit torque. At this time, even if there is a displacement such as eccentricity or inclination between the transmission shaft and the sun roller, the elastic member is deformed and can absorb the above-mentioned displacement. As a result of preventing an excessive force from being applied to the rollers, it is possible to prevent vibration of the planetary roller type transmission. In addition, it is possible to prevent an excessive force from being applied to the transmission shaft due to the above-described displacement. Further, since the elastic member can be interposed between the sun roller and the transmission shaft to eliminate the gap, noise caused by the gap can be prevented. Further, since the elastic member can absorb the impact, even if a gap is generated between the sun roller and the transmission shaft, noise caused by the gap can be reduced.

In particular, since the transmission shaft, the elastic member, and the sun roller can be nested, the elastic member can reduce the moment load applied to the sun roller from the transmission shaft, thereby reducing the vibration of the planetary roller type transmission. It can be reliably prevented.

Further, as described above, since the sun roller and the transmission shaft can tolerate positional deviation between each other during torque transmission, a high assembly accuracy is not required between them.
Assembly costs can be reduced. Further, it is possible to omit a high component accuracy necessary for increasing the assembly accuracy and reduce the component cost.

Further, since the elastic member can be easily deformed,
The sun roller and the transmission shaft can be easily attached and detached as compared with the case where members made of rigid bodies are press-fitted to each other, so that assembly costs can be reduced.

Since the transmission shaft can be arranged in the cylinder of the elastic member and the elastic member can be provided inside the sun roller, the size of the planetary roller type transmission can be reduced.

The torque transmission surface of the elastic member and the transmission shaft need only be engaged so as to transmit torque, and for example, a press-fitting structure can be exemplified. Further, since the torque transmission capability between the transmission shaft formed of the elastic member and the rigid member generally tends to be smaller than the torque transmission capability between the rigid members, the present drive connection structure is provided with a sun roller. It is preferable that the present invention be applied to a case where a small torque is required, for example, when a planetary roller type transmission having a sun roller as an input side is used as a speed reducer.

According to a second aspect of the present invention, in the drive coupling structure according to the first aspect, the elastic member comprises:
It is characterized by having a circular fitting hole into which a transmission shaft having a circumferential surface is press-fitted.

According to this configuration, the following operation is achieved in addition to the operation of the first aspect of the invention. That is, the press fit between the circumferential surfaces can reliably prevent the gap between the elastic member and the transmission shaft. Further, since the fitting hole and the connected member are circular, they can be manufactured accurately and at low cost, and the assembly is easy.

According to a third aspect of the present invention, there is provided a planetary roller type transmission, comprising: an annular outer ring member; a plurality of planetary rollers held by a carrier inside the outer ring member; and a sun roller around which the plurality of planetary rollers circumscribes. A drive connection structure according to claim 1 or 2 is provided.

According to this structure, the transmission shaft can be driven and connected to the sun roller via the elastic member, so that the planetary roller type transmission can achieve the effect of the invention described in claim 1 or 2.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A motor drive unit to which a planetary roller type transmission to which a drive connection structure according to an embodiment of the present invention is applied will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a motor drive unit provided with a planetary roller type transmission according to an embodiment of the present invention.

The motor drive unit 1 includes a motor 2 as a drive source having a rotating shaft 2a, and a rotating shaft 2a of the motor 2.
And a housing 4 as a fixing member for accommodating these components, and these are configured as an integrated unit. The housing 4 houses the planetary roller-type transmission 3 and the motor 2 while housing the planetary roller type transmission 3 and the motor 2 in the axial direction of the rotating shaft 2a (hereinafter referred to as the axial direction).
The end of the cylindrical portion 4a on the planetary roller type transmission 3 side is closed by an annular portion 4b extending inward in the radial direction. This drive connection structure is applied to the drive connection between the rotating shaft 2a and the sun roller 31 of the planetary roller transmission 3.

In the present drive coupling structure, the sun roller 31 of the planetary roller transmission 3 is formed of a cylindrical body, and a cylindrical elastic member 30 is provided on the inner peripheral surface 31a of the cylindrical body so as to be capable of transmitting a torque. The inner peripheral surface of the member 30 is a surface for transmitting torque to the rotating shaft 2a as a transmission shaft.

The details will be described below.

FIG. 2 is a side view of a main part of the planetary roller type transmission shown in FIG. Please refer to FIG. 1 and FIG.

The rotating shaft 2a is formed in a circular cross section, and its outer peripheral surface is used as a torque transmitting surface. The rotating shaft 2a protrudes from one end surface of the motor 2. To drive-connect the rotating shaft 2a and the planetary roller type transmission, the rotating shaft 2a may be pressed into the fitting hole 30a of the elastic member 30 in a press-fit state. .

The elastic member 30 is a solid cylindrical member formed of an elastically deformable material, and has substantially the same axial length as the sun roller 31. As the material of the elastic member 30, a resin material such as plastic, or a material capable of elastic deformation such as natural rubber or synthetic rubber can be used.

The outer peripheral surface 30b of the elastic member 30 is pressed into the sun roller 31 and the fitting hole 30a of the elastic member 30 is inserted.
The outer peripheral surface 20a of the rotating shaft 2a is press-fitted into the shaft. In this manner, the elastic member 30 is capable of transmitting torque by frictional force in a state where the elastic member 30 is pushed out from the inside by the rotating shaft 2a and tightened from the outside by the sun roller.
The elastic member 30 has a press fit, a thickness, and an elastic coefficient set so that a frictional force for transmitting torque can be obtained by an elastic restoring force generated at the time of press fitting.

The connection between the elastic member 30 and the sun roller 31 and the connection between the elastic member 30 and the rotating shaft 2a are not limited to press-fitting. For example, they may be connected by bonding.
Further, the bonding may be performed in a press-fit state. Thus, in the case of bonding, torque can be transmitted by the bonding force.

The sun roller 31 is made of a hard member and has an inner peripheral surface 31a connected to the elastic member 30 and an outer peripheral surface as a rolling surface on which the planetary roller 32 of the planetary roller type transmission 3 rolls. ing. The inner peripheral surface 31a of the sun roller 31
It has a circular cross section and is formed concentrically with the outer peripheral surface.

The planetary roller type transmission 3 includes the above-mentioned elastic member 30, the above-mentioned sun roller 31 connected to the elastic member 30, and a plurality of planetary rollers which revolve around the sun roller 31 while rolling around the outer peripheral surface thereof. 32, a cylindrical outer ring member 33 on which the planetary rollers 32 roll on the inner peripheral surface, and a carrier 34 for rotatably holding the plurality of planetary rollers 32. An output shaft 37 is fixed to the carrier 34. The output shaft 37, the carrier 34, the sun roller 31, and the elastic member 30 have the same rotation center axis, and this rotation center axis and the center axis of the inner peripheral surface of the outer ring member 33 are arranged concentrically. ing.

The carrier 34 has a cylindrical portion to which the output shaft 37 is joined, and a flange extending radially outward from the cylindrical portion. A plurality of shafts 35 extending in the axial direction are erected on this flange, and the planetary rollers 32 are rotatably supported on the same circumference at equal intervals via a bearing metal 36 fitted on the shaft 35. ing.

The planetary roller type transmission 3 has the following components. That is, a first bearing 41 that rotatably supports the output shaft 37, and a first holding member 44 that holds the first bearing 41 and is provided along the annular portion 4 b of the housing 4.
A first spacer 46 formed in the shape of a thin plate annularly interposed between the first holding member 44 and the outer ring member 33, and formed on the end face of the outer ring member 33 near the motor 2 and formed substantially in the same manner as the first spacer 46. The second spacer 47, a substantially disk-shaped second holding member 45 for sandwiching the second spacer 47 between the outer ring member 33, and the sun roller 31 held near the inner periphery of the second holding member 45. Bearing 42 for rotatably supporting the shaft
A third bearing 43 held by the carrier 34 to support the sun roller 31 in cooperation with the second bearing 42, a second holding member 45, a second spacer 47, an outer ring member 33, a first spacer 46, The first holding member 44 and a plurality of bolts 49 that pass through the annular portion 4b of the housing 4 and are screwed and fixed to the motor 2 are provided.

The first to third bearings 43 support the sun roller 31, the carrier 34, and the output shaft 37 so as to be concentric with the outer ring member 33, while suppressing the inclination of the rotation center axis thereof. Receives axial and radial loads on each part.

In the planetary roller type transmission 3, the outer ring member 33
Are fixed, the sun roller 31 is used as an input member, and the carrier 34 is used as an output member. The rotation of the motor 2 is transmitted from the rotation shaft 2a to the sun roller 31 via the elastic member 30, and the rotation shaft 2a, the elastic member 30, and the sun roller 31 rotate integrally to transmit torque. The sun roller 31 and the planetary roller 32, and the planetary roller 32 and the outer ring member 33 perform a rolling motion while reliably contacting each other in a state in which there is no play between each other and a pressing force is applied. Transmit power. When the sun roller 31 rotates, the planetary roller 32 revolves around the sun roller 31 while rotating in contact with the outer peripheral surface of the sun roller 31 and the inner peripheral surface of the outer ring member 33, and the carrier 34 is thereby moved. Rotate. At this time, the rotation of the carrier 34 is obtained by reducing the rotation of the rotating shaft 2a.

The interior of the planetary roller type transmission 3, for example, around the planetary roller 32, is filled with a lubricant such as grease. Generally, when the temperature is increased, these lubricants may increase the fluidity and leak to the outside. In order to prevent this, the planetary roller transmission 3 of the present embodiment
It has a closed structure.

The motor 2 is mounted on the cylindrical portion 4a of the housing 4.
The second holding member 45, the second spacer 47, the outer ring member 33, and the first spacer 46 are fitted, and the first holding member 44 is housed. An outer space is surrounded by these components, and an inner space is surrounded by the sun roller 31 and the output shaft 37 to define an annular space. The planetary roller 32 is arranged so as to be able to revolve around the annular space, and the annular space is a filling space G in which lubricant is stored.

The sealing of the filling space G is performed as follows. That is, the first holding member 44 and the first spacer 4
6, the outer ring member 33, the second spacer 47, and the second holding member 45 at the contact surfaces of the respective portions, for example, at both end surfaces of the first spacer 46 and the second spacer 47, a liquid sealing material is provided. Coated and sealed. Instead of applying a liquid sealing material, sealing may be performed with an O-ring.

Further, a housing 4 is disposed so as to cover the outside of each of the above-mentioned parts. The inner surface of the cylindrical portion 4a of the housing 4 and the outer peripheral surface of the motor 2 are fitted. Housing 4
The inner surface of the cylindrical portion 4a and the outer surface of the second holding member 45
Sealed by a ring 50. The inner surface of the annular portion 4b of the housing 4 and the portion near the inner diameter of the first holding member 44
It is sealed by an O-ring 50. Thus, even if the sealing with the liquid sealing agent is not sufficient, it is possible to reliably prevent the leakage of the lubricant.

Further, a first bearing 41 and a second bearing 42 are arranged at an axial end of the filling space G. These bearings 41 and 42 are seal-type bearings in which a sealing member is incorporated, and seal the inside and outside of the filling space G while rotatably supporting the sun roller 31 and the output shaft 37 which are rotating members. doing. The first bearing 41 and the second bearing 4
A seal member such as a separate oil seal may be provided in the vicinity of 2.

As described above, since the planetary roller type transmission 3 has a hermetic structure, evaporation of lubricant such as grease at a high temperature can be prevented. As a result, it is possible to prevent an increase in friction or the like due to a decrease in the lubricant, to prevent a reduction in power transmission efficiency or a failure, and to improve the life of the planetary roller transmission 3. Further, even if the temperature becomes high and the viscosity of the lubricant decreases, the lubricant flows to the outside because the lubricant is sealed inside the planetary roller type transmission 3 and in the filling space G. Therefore, it is possible to prevent the amount of the lubricant from being reduced, and it is possible to extend a maintenance interval such as filling of the lubricant. Further, since the inside of the planetary roller type transmission 3 is sealed from the outside, it is possible to prevent dust from entering, and to prevent dust from adhering to the planetary rollers 32 and the like.

Note that even with the configuration in which the O-ring 50 is omitted, the operation and effect of the above-described closed structure can be obtained.

The connection between the rotating shaft 2a of the motor 2 and the sun roller 31 will be described.

First, the elastic member 30 is pressed into the inner peripheral surface 31a of the sun roller 31. The rotary shaft 2a may be pushed into the fitting hole 30a of the elastic member 30, whereby the connection by press fitting and the alignment are completed at the same time. Moreover, press-fitting into the elastic member 30 is easy. The elastic member 30 may be fitted on the rotating shaft 2a, and the elastic member 30 in this state may be pressed into the inner peripheral surface of the sun roller 31.

As described above, according to the present embodiment, the cylindrical elastic member 30 is interposed between the sun roller 31 formed of a cylindrical body and the rotating shaft 2a as the transmission shaft. Thus, when the rotating shaft 2a is disposed in the cylinder of the elastic member 30, the rotating shaft 2a and the sun roller 31 are drivingly connected to each other and can rotate so that torque can be transmitted. At this time, the rotating shaft 2
When the elastic member 30 is deformed and can absorb the above-mentioned positional deviation even when there is a positional deviation such as eccentricity or inclination between the sun roller 31 and the sun roller 31, the solar roller 31 As a result of preventing excessive force from being applied to
The vibration of the planetary roller type transmission 3 can be prevented.
Further, since an excessive force can be prevented from being applied to the rotating shaft 2a due to the above-described displacement, it is possible to prevent the motor 2 from generating noise or vibration. Further, the elastic member 30
Since the gap can be eliminated by being interposed between the sun roller 31 and the rotating shaft 2a, noise caused by the gap can be prevented. Further, since the elastic member 30 can absorb the impact, even if a gap is generated between the sun roller 31 and the rotating shaft 2a, noise caused by the gap can be reduced.

Further, since the elastic member 30 can absorb the impact, the torque can be smoothly transmitted even when the rotation shaft 2a has uneven rotation.

In particular, since the rotating shaft 2a, the elastic member 30, and the sun roller 31 are nested, the elastic member 30 can reduce the moment load applied to the sun roller 31 from the rotating shaft 2a. Vibration of the transmission 3 can be reliably prevented.

Further, as described above, since the sun roller 31 and the rotating shaft 2a can tolerate positional deviation between each other at the time of torque transmission, high assembly accuracy is not required between them, resulting in an assembly cost. Can be reduced. Further, it is possible to omit a high component accuracy necessary for increasing the assembly accuracy and reduce the component cost. In addition, since the elastic member 30 is easily deformed, the sun roller 31 and the rotating shaft 2a can be easily attached and detached as compared with the case where members made of rigid bodies are press-fitted, so that assembly cost can be reduced. Thus, the planetary roller transmission 3 can be made inexpensive. Since the rotating shaft 2a can be disposed inside the cylinder of the elastic member 30 and the elastic member 30 can be provided inside the sun roller 31,
The planetary roller transmission 3 can be reduced in size.

The torque transmitting surface on the inner periphery of the elastic member 30 and the rotating shaft 2a need only be engaged so as to transmit torque, and examples thereof include a press-fitting structure and an adhesive structure. Also, usually
Since the torque transmission capability between the elastic member 30 and the rotating shaft 2a formed of the rigid member tends to be smaller than the torque transmission capability between the rigid members, the present drive connection structure is applied to the sun roller 31. When such a torque is small, it is preferable to apply, for example, when the planetary roller type transmission 3 having the sun roller 31 as the input side is used as a speed reducer.

The circular fitting hole 30a of the elastic member 30
Since the circumferential surface of the rotating shaft 2a is press-fitted into the shaft, a gap between the elastic member 30 and the rotating shaft 2a can be reliably prevented. Further, since the fitting hole 30a and the rotary shaft 2a as a connected member are circular, they can be manufactured accurately and at low cost, and the assembly is easy. As a result, the cost can be further reduced.

Further, since the planetary roller type transmission 3 is provided with the above-described drive connection structure, only by connecting the rotation shaft 2a to the fitting hole 30a of the elastic member 30 of the planetary roller type transmission 3,
The above effects can be obtained.

Further, since the sun roller 31 and the elastic member 30 are press-fitted, and the elastic member 30 and the rotary shaft 2a are also press-fitted, a gap between these members can be eliminated. In this case, misalignment is likely to occur, but the sun roller 31 and the rotating shaft 2a can be easily centered according to the shape accuracy of the component.

When bonding between the sun roller 31, the elastic member 30, and the rotating shaft 2a, a gap may be provided between opposing surfaces, and the gap may be filled with an adhesive. At this time, the centering of the rotating shaft 2a and the sun roller 31 can be adjusted in a state where there is a gap between the surfaces, and if the adhesive is thereafter cured, the centering of the rotating shaft 2a and the sun roller 31 is surely performed. 31 can be obtained.

In the above embodiment, the planetary roller type transmission 3 has the outer ring member 33 fixed and the carrier 34 used as the output member. However, the present invention is not limited to this. For example, the outer ring member 33 may be an output member, and the carrier 34 may be a fixing member.

In the above-described embodiment, the O-ring 5
Although 0 is provided, the present invention can be applied to a configuration in which the O-ring 50 is omitted.

In the above-described embodiment, the planetary roller type transmission 3 is configured as a unit having each part such as the first bearing 41, but is not limited to this.
The planetary roller type transmission only needs to include the sun roller 31, the planetary roller 32, the carrier 34, and the outer ring member 33.

In addition, various design changes can be made without changing the gist of the present invention.

[0058]

According to the first aspect of the present invention, the following effects can be obtained. That is, since the cylindrical elastic member is interposed between the sun roller formed of the cylindrical body and the transmission shaft, the elastic member can absorb the eccentricity, inclination, and the like generated between the transmission shaft and the sun roller. In addition, it is possible to prevent an excessive force from being applied to the sun roller and the transmission shaft, and to prevent vibration of the planetary roller type transmission. In particular, a transmission shaft, an elastic member,
When the sun roller and the sun roller can be arranged in a nested manner, vibration of the planetary roller transmission can be reliably prevented. Further, the elastic member can prevent noise caused by a gap between the sun roller and the transmission shaft. Further, since the elastic member is interposed, high assembly accuracy is not required between the sun roller and the transmission shaft, and the sun roller and the transmission shaft can be easily attached and detached. As a result, assembly costs can be reduced. Also,
Since high component accuracy for high assembly accuracy can be omitted, component costs can also be reduced.

According to the second aspect of the present invention, the following effects are obtained in addition to the effects of the first aspect of the present invention. That is, since the transmission shaft is pressed into the circular fitting hole of the elastic member,
Gaps between them can be reliably prevented, and they can be manufactured accurately and at low cost, and assembly is easy.

According to the third aspect of the present invention, the planetary roller type transmission is provided with the above-described drive connection structure.
Or the effect of the invention described in 2 can be obtained.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a schematic configuration of a motor drive unit provided with a planetary roller type transmission according to an embodiment of the present invention.

FIG. 2 is a side view of a main part of the planetary roller transmission shown in FIG.

[Explanation of symbols]

 2a rotating shaft (transmission shaft) 3 planetary roller type transmission 30 elastic member 30a fitting hole 31 sun roller 31a inner peripheral surface 32 planetary roller 33 outer ring member 34 carrier

Claims (3)

[Claims] 1. A drive connection structure for drivingly connecting said sun roller and a transmission shaft in a planetary roller transmission in which a plurality of planetary rollers held by a carrier are interposed between an outer race member and a sun roller. The sun roller is formed of a cylindrical body, and a cylindrical elastic member is provided on an inner peripheral surface of the cylindrical body so as to transmit torque, and the inner peripheral surface of the elastic member is used as a torque transmitting surface to a transmission shaft. A drive connection structure characterized by the following. 2. The drive connection structure according to claim 1, wherein the elastic member has a circular fitting hole into which a transmission shaft having a circumferential surface is press-fitted. 3. The drive coupling structure according to claim 1, wherein an annular outer ring member, a plurality of planetary rollers held by a carrier inside the outer ring member, and a sun roller around which the plurality of planetary rollers are circumscribed. And a planetary roller-type transmission.