JP2010014145A - Variable reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable reduction gear capable of outputting input driving force without depending on frictional force, and enabling the variable reduction gear ratio. <P>SOLUTION: This variable reduction gear 1 has a first rocking link 2 rockable around a first rotary shaft Q1 by driving force from an external part and having a first guide means arranged in the longitudinal direction, a second rocking link 3 rockable around a second rotary shaft Q2 outputting the driving force and having a second guide means arranged in the longitudinal direction, a moving member 4 movable in the distance direction between the first rotary shaft Q1 and the second rotary shaft Q2 and having a third guide means arranged in the direction orthogonal to the distance direction, a moving means 6 for moving the moving member 4 in the distance direction between the first rotary shaft Q1 and the second rotary shaft Q2, and a post 5 movably connected along the first guide means, the second guide means and the third guide means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a variable speed reducer that can transmit a driving force without depending on a frictional force and can continuously change a reduction ratio.

  As a typical speed reducer, a gear using gears, a CVT (Continuously Variable Transmission) used for transmitting a driving force of an automobile, and the like are known.

  As a general reduction gear using a gear, for example, there is a spur gear reduction gear. A spur gear is a gear having teeth cut parallel to a rotation axis, and tooth traces are parallel to the axis on a cylindrical surface. Spur gear reducers can increase (or decrease) driving force and decrease (or increase) rotational speed by meshing two gears, and are also used in robot joint mechanisms and the like.

  In addition, CVT applies a large pressing force between the rotating shafts instead of providing gear teeth to transmit the driving force by a frictional force in order to make the reduction gear ratio variable. As the CVT, for example, as shown in FIG. 9, there is a CVT 100 in which two tapered rotating shafts 101 and 102 are opposed to each other and a roller 103 is provided between them. In the CVT 100, the reduction ratio can be continuously changed by moving the roller 103.

  However, a spur gear or the like is a fixed speed reducer with a constant reduction gear ratio because the gear ratio is the reduction gear ratio (transmission gear ratio). Therefore, the reduction ratio cannot be changed continuously.

  In addition, since the CVT transmits the rotational driving force by the frictional force, it is necessary to increase the frictional force that acts between the rotating shafts that transmit the driving force in order to reduce the size. is there. Therefore, there is a problem in using CVT for a rehabilitation robot, a welfare robot, or the like that requires a reduction in size.

  The present invention has been made for the purpose of solving various problems as described above, and can output the driving force input to the rotating shaft to the rotating shaft on the output side without depending on the frictional force. An object of the present invention is to provide a variable speed reducer that can change the speed reduction ratio.

  In order to achieve the above object, the variable speed reducer according to claim 1 is capable of swinging about the first rotation shaft by an external driving force and is provided along the longitudinal direction. A first swing link having means and a second swing means having second guide means provided along the longitudinal direction and swingable about a second rotating shaft that outputs the driving force. A moving member having a link and a third guide means that is movable in a distance direction between the first rotating shaft and the second rotating shaft and is provided along a direction orthogonal to the distance direction; Moving means for moving the moving member in the distance direction between the first rotating shaft and the second rotating shaft, and movable along the first guiding means, the second guiding means, and the third guiding means And a post connected to the second member, and the moving member includes the post. It is characterized in that transmitting by varying decelerate the driving force inputted to the first rotary shaft to the second rotating shaft by adjusting the distance ratio of the rotational shaft and the second rotation axis.

  The variable speed reducer according to a second aspect is characterized in that the moving means moves the moving member along the ball screw via a nut member that is screwed to a ball screw that is rotationally driven by the driving means.

  According to the variable speed reducer of claim 1, the moving member moves the moving member between the first rotating shaft that receives the driving force and the second rotating shaft that outputs the driving force. The distance ratio between the first rotating shaft and the second rotating shaft can be adjusted. In addition, the first swing link that can swing around the first rotation shaft and the second swing link that can swing around the second rotation shaft are respectively provided along the longitudinal direction. Guide means and second guide means are provided, and the first guide means, the second guide means, and the third guide means provided on the moving member are respectively connected to the posts. Therefore, the ratio of the distance from the first rotating shaft to the post and the distance from the second rotating shaft to the post is adjusted by adjusting the distance ratio between the first rotating shaft and the second rotating shaft of the moving member. Then, the input driving force can be variably decelerated and transmitted to the second rotating shaft by swinging about the first rotating shaft by an external driving force. That is, it is possible to continuously change the reduction ratio by adjusting the movement of the moving member.

  Further, no frictional force is required to transmit the driving force input to the first rotating shaft to the second rotating shaft. For this reason, even when the speed reducer is downsized, it is not necessary to apply a large frictional force between the rotating shafts that transmit the driving force, so that the speed reducer can be downsized. As a result, it can also be used for joint mechanisms such as rehabilitation robots and welfare robots that need to ensure safety.

  According to the variable speed reducer of the second aspect, the moving member can be moved via the nut member by rotating the ball screw by the driving means. Thereby, the distance ratio between the first rotating shaft and the second rotating shaft of the moving member can be adjusted, so that the reduction ratio can be made continuously variable.

  Hereinafter, a variable reduction gear 1 according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the variable speed reducer 1 according to the first embodiment of the present invention includes a first swing link 2, a second swing link 3, a moving member 4, a post 5, and moving means ( A ball screw mechanism) 6, and the driving force input to the first rotating shaft Q1 is rotated second by the swinging motion of the cross link structure disposed between the first rotating shaft Q1 and the second rotating shaft Q2. It is transmitted to the axis Q2.

  One end of the first swing link 2 is pivotally supported so as to be swingable about the first rotation axis Q1. In FIG. 1, the pedestal on which the first rotation axis Q1 is supported is omitted, but in actuality, the first rotation axis Q1 and the second rotation axis Q2 are supported on the pedestal. The first oscillating link 2 rotates (oscillates) about the first rotating shaft Q1 when a rotational driving force is input from the first rotating shaft Q1 by a driving means (not shown) or the like.

  Further, the first swing link 2 is provided with a guide groove 7 along the longitudinal direction thereof, and includes a slide member 8 that is slidable along the guide groove 7. The slide member 8 is connected to the post 5 and is formed so that the post 5 can be inserted vertically. Therefore, the post 5 can also move along the guide groove 7 as the slide member 8 slides along the guide groove 7. In the first swing link 2, a space X having a width that allows the post 5 to pass therethrough is formed along the longitudinal direction as shown in FIG. 2 together with the guide groove 7. When connecting the slide member 8 and the post 5, as shown in FIG. 3, the slide member 8 and the post 5 are connected via the linear bush 9 and the spherical bearing 10 in the vertical direction. Is preferable. Specifically, the linear bush 9 is attached to the post 5, and the linear bush 9 is further attached to the spherical bearing 10. Then, the spherical bearing 10 is connected to the slide member 8. Thereby, it becomes a structure which accept | permits the minute error of the angle and the vertical position accompanying the rocking | fluctuation etc. of the 1st rocking | fluctuation link 2. FIG.

  The second swing link 3 is provided so as to be swingable about the second rotation shaft Q2 that outputs the rotational driving force input from the first rotation shaft Q1. Similarly to the first swing link 2, the second swing link 3 is also provided with a guide groove (not shown) along the longitudinal direction thereof, and includes a slide member 8a that is slidable along the guide groove. ing. Further, the slide member 8 a is connected to the post 5. Therefore, as the slide member 8a slides along the guide groove, the post 5 can also move along the guide groove. Further, like the slide member 8, the slide member 8a is preferably connected to the post 5 using a linear bush and a spherical bearing. Thereby, it becomes a structure which accept | permits a minute error of an angle or an up-and-down position.

  The moving member 4 is provided so as to be movable in the distance direction between the first rotating shaft Q1 and the second rotating shaft Q2 by the ball screw mechanism 6. The ball screw mechanism 6 includes a driving unit 11 including a small motor, a timing belt 12 that transmits a rotational driving force of the driving unit 11, a ball screw 13 that rotates by the rotational driving force transmitted from the timing belt 12, And a nut member 14 screwed into the ball screw 13. The ball screw 13 is provided in the same direction as the distance direction between the first rotating shaft Q1 and the second rotating shaft Q2, and rotates when the rotational driving force by the driving means 11 is transmitted via the timing belt 12. As the ball screw 13 rotates, the nut member 14 screwed into the ball screw 13 moves along the ball screw 13. The ball screw mechanism 6 itself is fixed to a pedestal (not shown).

  The nut member 14 is connected to the moving member 4, and as the nut member 14 moves along the ball screw 13, the moving member 4 moves in the distance direction between the first rotating shaft Q 1 and the second rotating shaft Q 2. It becomes possible to move. In the present embodiment, the ball screw mechanism 6 in which the nut member 14 moves along the ball screw 13 as the ball screw 13 rotates via the timing belt 12 by the rotational driving force of the drive unit 11 is taken as an example of the moving unit. However, the moving means is not limited to this, and the nut member 14 may be configured to be movable along the ball screw 13 by directly rotating the ball screw 13 by the driving means 11. In addition to the ball screw mechanism 6, any device capable of linear movement can be used as appropriate.

  The moving member 4 is provided with a guide groove 7a along a direction orthogonal to the distance direction of the first rotation axis Q1 and the second rotation axis Q2, and a slide member that is slidable along the guide groove 7a. 8b. Further, the slide member 8 b is connected to the post 5. Accordingly, as the slide member 8b slides along the guide groove 7a, the post 5 can also move along the guide groove 7a.

  The post 5 is formed in a rod shape as shown in FIG. 1, and is connected to the first swing link 2, the second swing link 3, and the moving member 4 through slide members 8, 8 a, 8 b. ing. In the present embodiment, as shown in FIG. 1, an example is shown in which the second swing link 3 is positioned above the first swing link 2, but the present invention is not limited to this configuration. The positions of the first swing link 2 and the second swing link 3 may be interchanged.

  FIG. 1A shows a state in which the first swing link 2 and the second swing link 3 of the variable speed reducer 1 are at the reference position. In this reference position state, the distance direction between the first rotating shaft Q1 and the second rotating shaft Q2 and the guide groove 7 of the first swing link 2 and the guide groove of the second swing link 3 face the same direction. become.

  In this state, as shown in FIG. 1B, when a rotational driving force is input to the first rotating shaft Q1, the first swing link 2 rotates (swings) about the first rotating shaft Q1. Move). As the first swing link rotates, the post 5 moves along the guide groove 7a via the slide member 8b. The second swing link 3 also rotates in the direction opposite to the direction in which the first swing link 2 rotates about the second rotation axis Q2 as the first swing link 2 rotates.

  At this time, in order to variably decelerate and output the rotational driving force input from the first rotating shaft Q1 to the second rotating shaft Q2, the moving member 4 is connected to the first rotating shaft Q1 and the first rotating shaft Q1 by the ball screw mechanism 6. The reduction ratio can be adjusted by moving the rotary shaft Q2 in the distance direction.

  In the state shown in FIG. 1A, as shown in FIG. 2, the ratio of the distance R1 from the first rotation axis Q1 to the post 5 and the distance R2 from the second rotation axis Q2 to the post 5 is the reduction ratio. . In this case, the reduction ratio n = −R1 / R2, and as the moving member 4 moves, the distance R1 from the first rotation axis Q1 to the post 5 and the distance R2 from the second rotation axis Q2 to the post 5 Since the ratio can be adjusted, the reduction ratio n can be made continuously variable.

  Next, an embodiment as a driving force transmission mechanism using the variable speed reducer 1 will be described. As shown in FIGS. 4 and 5, leaf springs 15 are provided on both sides of the first swing link 2. One end of the leaf spring 15 is fixed to the base 17, and a roller 16 is provided at the other end. As shown in FIG. 5A, the roller 16 is provided so as to contact the side surface of the first swing link 2 when the first swing link 2 is in the reference position.

  As shown in FIG. 5 (b), when the first swing link 2 rotates around the first rotation axis Q1, the first swing link 2 contacts the side surface on the rotational direction side. The roller 16 that is in contact with the side surface moves on the side surface according to the rotation of the first swing link 2. At this time, for example, by providing a guide rail or the like for guiding the roller 16 on the side surface of the first swing link 2, the roller 16 is prevented from being displaced from the side surface of the first swing link 2. be able to.

  Further, as schematically shown in FIG. 6, the leaf spring 15 has a force F <b> 1 of the leaf spring 15 acting on a distance from the first rotation axis Q <b> 1 to R <b> 3 as the first swing link 2 rotates. It will be. Accordingly, in addition to the driving force input from the first rotating shaft Q1, the force F1 of the leaf spring 15 also acts on the first swing link 2, so that the effect of the leaf spring 15 is made to be the second rotation. It becomes possible to output to the axis Q2 as a variable characteristic. When the first swing link 2 is located at the reference position, the force F1 of the leaf spring 15 is orthogonal to the longitudinal direction of the first swing link 2.

  On the other hand, the leaf spring 15a opposite to the rotation direction of the first swing link 2 is separated from the side surface of the first swing link 2 as shown in FIGS. Therefore, in this state, the force of the leaf spring 15a does not act, but when the first swing link 2 rotates toward the leaf spring 15a, the force of the leaf spring 15a is the same as described above. Will work. Therefore, by providing the leaf springs 15 and 15a on both sides of the first swing link 2 in this way, the effect of the leaf spring can be obtained regardless of which direction the first swing link 2 rotates. 4 and 5 show an example in which the leaf springs 15 and 15a are provided in parallel with the first swing link 2 in a state where the first swing link 2 is at the reference position. However, it is not limited to this configuration.

  FIG. 7 shows an example in which a rotary damper 18 is attached to the first rotating shaft Q1 via a spur gear mechanism 17 in order to add a viscous characteristic. As the rotary damper 18, a rotary damper using a braking force generated by the viscous resistance of oil can be used.

  The braking torque of the rotary damper 18 is such that the value of the generated torque changes according to the rotational speed, and the torque increases as the rotational speed increases, and the torque decreases as the rotational speed decreases. . Therefore, by providing the rotary damper 18 on the first rotating shaft Q1 side in this way, it is possible to output with a viscosity characteristic added on the second rotating shaft Q2 side. Here, the rotary damper 18 utilizing the viscous resistance of oil is taken as an example, but the means for adding the viscous characteristic is not limited to this, and other swing dampers utilizing the oil pressure are also used. Etc. can also be used.

  FIG. 8 shows an embodiment as a redundant joint mechanism using the variable speed reducer 1. Conventionally, when a high speed reducer is used, there is a problem that the back drivability is poor. Therefore, in the redundant joint mechanism shown in FIG. 8, the back drivability is improved by using the variable speed reducer 1.

  The redundant joint mechanism shown in FIG. 8 rotates the driving force from the motor 19 attached to the first rotating shaft Q1 via the spur gear 17 and the driving force from the motor 21 fixed to the pedestal 20 in the second rotation. This is a 2-input 1-output mechanism capable of transmitting to the link member 23 attached to the shaft Q2.

  Pulleys 24, 24 a fixed to the rod member 23 are provided on the side of the second swing link 3 different from the second rotation axis Q <b> 2. And the pulley 25 and the pulley 26 are provided on the 2nd rotating shaft Q2, The wire 27 is interposed in each pulley 24,24a, 25,26. Further, the link member 22 is swingably attached to the pulley 26 on the second rotation shaft Q2.

The angular velocity ω _J of the link member 22 that rotates about the second rotation axis Q2 in this joint mechanism is expressed as the following formula 1 when the radius of the pulley 25 is R _M and the radius of the pulley 26 is R _J. Is done. However, ω _M is an angular velocity around the second rotation axis Q2 of the pulley 25, and ω _A is an angular velocity around the second rotation axis Q2 of the second swing link 3.

Thus, for example, if the radius _{R J} of the radius _{R M} and the pulley 26 of the pulley 25 have the same radius, the alpha ₁ = 1. In this case, when α ₁ = 1 is substituted in Formula 1, it is expressed as Formula 2. This equation 2 shows that a certain amount of movement of ω _M is the same amount of movement opposite to ω _J , and a certain amount of movement of ω _A is twice that of ω _J. It represents the movement of the same direction.

  Therefore, even when the motor 21 is difficult to move, back drivability can be improved by configuring a mechanism as shown in FIG. In other words, when a force is applied to the link member 22, displacement and acceleration can be easily generated, which is effective as a mechanism used for rehabilitation and the like.

It is a schematic perspective view which shows an example of the variable reduction gear which concerns on this invention, Comprising: (a) has shown the state which has a 1st rocking | fluctuation link in a reference position, (b) has shown the 1st rocking | fluctuation link. A state of swinging motion is shown. It is a schematic plan view of the variable speed reducer shown in FIG. It is a schematic explanatory drawing for demonstrating the mode of a connection. It is a schematic explanatory drawing which shows the Example using the variable reduction gear which concerns on this invention. FIG. 5 is a schematic plan view of the embodiment shown in FIG. 4, where (a) shows a state where the first swing link is at a reference position, and (b) shows a swing motion of the first swing link. The state at the time is shown. It is a schematic plan view for explaining the action of the leaf spring. It is a schematic explanatory drawing which shows the other Example of the variable reduction gear which concerns on this invention. It is a schematic explanatory drawing which shows the Example as a redundant joint mechanism using the variable reduction gear which concerns on this invention. It is a schematic front view which shows an example of CVT in a prior art.

Explanation of symbols

1 variable speed reducer 2 first swing link 3 second swing link 4 moving member 5 post 6 moving means (ball screw mechanism)
7, 7a Guide grooves 8, 8a, 8b Slide member 11 Driving means 12 Timing belt 13 Ball screw 14 Nut member Q1 First rotating shaft Q2 Second rotating shaft

Claims (2)

A first swinging link having a first guide means which is swingable about the first rotation axis by an external driving force and is provided along the longitudinal direction;
A second oscillating link that is oscillatable about a second rotating shaft that outputs the driving force and has second guide means provided along the longitudinal direction;
A moving member that is movable in the distance direction between the first rotating shaft and the second rotating shaft and has third guide means provided along a direction orthogonal to the distance direction;
Moving means for moving the moving member in a distance direction between the first rotating shaft and the second rotating shaft;
A post connected to be movable along the first guide means, the second guide means, and the third guide means;
By adjusting the distance ratio between the first rotating shaft and the second rotating shaft of the moving member by the moving means, the driving force input to the first rotating shaft is variably decelerated to the second rotating shaft. A variable speed reducer characterized by transmitting.   2. The variable speed reducer according to claim 1, wherein the moving unit moves the moving member along the ball screw via a nut member that is screwed into a ball screw that is rotationally driven by the driving unit.

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