WO2017110252A1 - Differential gear device - Google Patents

Abstract

In order to enable increasing the number of years of service life while avoiding becoming bulkier, this differential gear device is provided with: a first rotating body, a second rotating body, a third rotating body and a fourth rotating body, each of which has a rotation axis that extends in parallel to one direction; a drive unit which axially drives at least the first rotating body; and an endless transmission member which, in a plane intersecting with the one direction, is arranged across the first rotating body, the second rotating body, the third rotating body and the fourth rotating body, wherein, by driving the drive unit, the third rotating body and the fourth rotating body are made to carry out linear motion.

Description

Differential

The present invention relates to a differential device. In particular, the present invention relates to a differential device that causes two movable elements to move straight forward.

In recent years, human body-mounted robots that support or assist human movements are known. The human body-mounted robot includes, for example, a joint portion to be worn by the user, a sensor for detecting the user's intention or state, or a surrounding situation, an actuator that applies driving torque to the joint portion, and a control device. It is prepared for. In general, an actuator includes a motor and a transmission that converts high-speed rotation of the motor into low-speed rotation suitable for human movement. The transmission transmits the rotation of the motor to the joint at a gear ratio of 1/50 to 1/200, for example. The actuator is configured by combining, for example, a harmonic drive (registered trademark) or a worm gear and a DC motor. Another differential gear includes a sun gear, a ball gear, and a plurality of planetary gears. The reduction gears using these gear mechanisms have a problem that it is necessary to use a material having high rigidity so as not to cause tooth chipping, which is relatively expensive.

On the other hand, there is an alternative device that can achieve a reduction ratio equivalent to that of a gear mechanism by using a cable, a belt, or a chain instead of a gear. These devices use a mechanism of a differential pulley. For example, a rotating body including two pulleys having different diameters that can rotate integrally, and a load that is suspended below the rotating body to support a load 1. Two pulleys and an endless rope or an endless chain disposed across these three pulleys. The differential pulley device can be configured at a relatively low cost, and even a heavy object such as a mining bucket or boat can be easily moved up and down by the operator's force. Furthermore, as shown in Patent Document 1, there is a differential pulley actuator in which a motor is added to a conventional differential pulley device. Such a differential pulley actuator can move the load forward and backward with a relatively small force by the driving force of the motor, not by the operator.

International Publication No. 1989/010242

However, differential pulley actuators equipped with motors have a relatively short service life and are often not designed on the premise of long-term continuous use. The large driving force that can be transmitted inside the apparatus shortens the life of an endless transmission member such as a cable unless various parts are enlarged. Such an increase in the size of the parts makes it difficult to apply the differential pulley actuator to a relatively small system such as a human-mounted robot.

In particular, when an object rotated by an actuator, such as a joint part of a human body-mounted robot, can be used while reversing the direction of rotation, two movable elements having reverse directions in each actuator are provided on one actuator. It is necessary to provide it. In this case, a larger driving force is required, and the life of an endless transmission member such as a cable is likely to be further shortened.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved differential device capable of improving the service life without increasing the size. .

In order to solve the above problems, according to an aspect of the present invention, a first rotating body, a second rotating body, a third rotating body, and a first rotating body each having a rotation axis extending in parallel along one direction. 4 rotators, a drive unit for rotating the shaft of at least the first rotator, and a plane intersecting one direction, the first rotator, the second rotator, the third rotator, and the fourth And an endless transmission member disposed over the rotating body of the first and second differential members, wherein the third rotating body and the fourth rotating body each move linearly by driving the drive unit. The

According to the differential device of the present invention, the endless transmission member is disposed across the first rotating body, the second rotating body, the third rotating body, and the fourth rotating body on substantially the same plane. Is done. Therefore, as an endless transmission member, not only a cable that drives a rotating body by frictional force, but also a belt or a chain that drives the rotating body by meshing teeth can be used, without increasing the size of each component, The service life can be improved.

The amount of the endless transmission member delivered by the first rotating body when the drive unit is driven may be different from the amount of the endless transmission member delivered by the second rotating body.

The endless transmission member is wound around at least the first rotating body, the fourth rotating body, the second rotating body, and the third rotating body in this order, and is then wound around the first rotating body again and driven. When the length of the endless transmission member extending from the first rotating body to the second rotating body through the third rotating body is increased by driving the unit, the first rotating body to the fourth rotating body While the length of the endless transmission member that reaches the second rotating body via the rotating body is shortened, the endless transmission member that reaches the second rotating body via the third rotating body from the first rotating body When the length is shortened, the length of the endless transmission member extending from the first rotating body to the second rotating body via the fourth rotating body may be increased.

When the driving unit is driven, the first rotating body and the second rotating body may rotate at different speeds.

It may be provided with at least one driven rotor for changing the locus of the endless transmission member.

The radius of the first rotating body and the radius of the second rotating body may be different from each other.

A fifth rotating body fixed to the rotating shaft of the first rotating body, a sixth rotating body fixed to the rotating shaft of the second rotating body, a fifth rotating body, and a sixth rotating body; A rotation transmission unit including a wound second endless transmission member may be provided, and the second rotation body may rotate by receiving the rotation of the first rotation body via the rotation transmission unit.

A second driving unit that rotationally drives the second rotating body may be provided.

The second rotating body may rotate by transmitting the rotation of the first rotating body via a gear mechanism.

The first rotating body is a driving pulley, the second rotating body is a driven pulley, and a continuously variable transmission that changes the pitch diameter of at least one of the driving pulley and the driven pulley is provided. Good.

The endless transmission member may be an endless belt, an endless chain, or an endless cable.

The third rotating body and the fourth rotating body may be connected to cables fixed or wound around the rotation operation unit, respectively, and the differential device may rotate the rotation operation unit.

The rotation operation unit may be a joint part of a human-mounted robot.

The rotation operation part has a long diameter part and a short diameter part, and when the rotation operation part rotates, the long diameter part is tensioned to the cable connected to the third rotation body or the cable connected to the fourth rotation body. May be given.

As described above, according to the present invention, the service life can be improved without increasing the size of the differential device in which the linear movement of the two movable elements is performed.

It is a schematic diagram which shows the differential gear concerning 1st Embodiment. It is a perspective view of the differential gear concerning the embodiment. It is explanatory drawing which shows the human body mounting robot to which the differential gear concerning the embodiment is applied. It is a schematic diagram which shows the differential gear concerning 2nd Embodiment. It is a perspective view of the differential gear concerning the embodiment. It is a schematic diagram which shows the differential gear concerning 3rd Embodiment. It is a schematic diagram which shows the differential gear concerning 4th Embodiment. It is a perspective view which shows the differential gear concerning 5th Embodiment. It is a schematic diagram which shows the differential gear concerning 6th Embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. First Embodiment>
(1-1. Configuration of differential device)
First, a configuration example of the differential device 10 according to the first exemplary embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic view of the main part of the differential device 10 as viewed along the extending direction of the rotation shaft of each pulley, and FIG. 2 is a perspective view of the main part of the differential device 10.

The differential device 10 includes a first pulley 30, a second pulley 40, a third pulley 60, a fourth pulley 70, and a fifth pulley 50. The pulley is an example of a rotating body in the present invention. Further, the differential device 10 includes a motor 20 as a drive unit that rotates the first pulley 30, a first pulley 30, a second pulley 40, a third pulley 60, a fourth pulley 70, and The endless belt 26 is provided as an endless transmission member disposed over the fifth pulley 50.

The motor 20 is driven by a control device (not shown). As the motor 20, for example, a servo motor or a stepping motor is used, but it is not limited to this example. The motor 20 has a rotating shaft 22 that outputs rotational torque. The rotating shaft 22 is connected to the axial center portion of the first pulley 30.

The first pulley 30, the second pulley 40, the third pulley 60, the fourth pulley 70, and the fifth pulley 50 each have a rotation axis along the axial direction of the rotation shaft 22 of the motor 20. . The first pulley 30, the second pulley 40, the third pulley 60, the fourth pulley 70, and the fifth pulley 50 are each provided with an endless belt 26 on the circumferential surface. The endless belt 26 is wound around the first pulley 30, the fourth pulley 70, the second pulley 40, the fifth pulley 50, and the third pulley 60 in this order and wound around the first pulley 30 again. Is done. The peripheral surfaces of the first pulley 30, the second pulley 40, the third pulley 60, the fourth pulley 70, and the fifth pulley 50 are located on a plane orthogonal to the rotating shaft 22 of the motor 20. The endless belt 26 is wound and disposed on the plane.

That is, the peripheral surfaces of the first pulley 30, the second pulley 40, the third pulley 60, the fourth pulley 70, and the fifth pulley 50 are on a plane orthogonal to the rotation shaft 22 of the motor 20. Therefore, the endless transmission member is not twisted. For this reason, the endless belt 26 can be used as an endless transmission member. The endless belt 26 may be, for example, a wire-made rubber belt, a high-strength woven belt, a metal belt, or the like. An endless chain may be used instead of the endless belt 26. The endless belt 26 or the endless chain has higher strength than the cable that drives the pulley by frictional force, improves the transmission efficiency of the driving force, and can improve the service life. In addition, the differential gear 10 concerning this embodiment can be applied also when an endless transmission member is an endless cable.

The first pulley 30 is connected to the rotating shaft 22 of the motor 20 and rotates about the rotating shaft 22. The first pulley 30 is provided with a drive gear 32 that rotates in the same manner as the shaft of the first pulley 30 rotates. In addition, the second pulley 40 is provided with a driven gear 42 that rotates in the same manner as the second pulley 40 rotates. The second pulley 40 and the driven gear 42 are rotatably supported with respect to a fixed portion (not shown). The driven gear 42 meshes with the drive gear 32, and when the first pulley 30 is rotated by the motor 20, the rotation is transmitted to the second pulley 40 via the drive gear 32 and the driven gear 42. The second pulley 40 rotates on the axis. In the illustrated example, the number of teeth of the drive gear 32 is larger than the number of teeth of the driven gear 42. Therefore, the rotation speed of the second pulley 40 is faster than the rotation speed of the first pulley 30.

The fifth pulley 50 is rotatably supported with respect to a fixed portion (not shown). The fifth pulley 50 is one of the driven rotators, and the driving force is transmitted by the endless belt 26 that moves forward and backward along the arrangement direction by the shaft rotation of the first pulley 30 and the second pulley 40. Rotate the shaft. The fifth pulley 50 changes the trajectory of the endless belt 26 delivered by the second pulley 40 toward the third pulley 60. The third pulley 60 and the fourth pulley 70 have the same diameter and are rotatably supported by the endless belt 26. The third pulley 60 and the fourth pulley 70 are supported so as to be capable of moving forward and backward along predetermined directions. For example, the third pulley 60 and the fourth pulley 70 are urged upward by a coil spring whose one end is fixed to a fixing portion (not shown) (not shown) on the upper side in the drawing. A load may be applied to the lower side in the figure.

(1-2. Operation of differential device)
Next, the operation of the differential device 10 according to the present embodiment will be described with reference to FIG. Here, variables are defined as follows.
ρ: Motor rotation angle (radians)
R: radius of the first pulley 30 r: radius of the second pulley 40 i: reduction ratio between the drive gear 32 and the driven gear 42 θ1: rotation angle (radian) of the first pulley 30
θ2: rotation angle (radian) of the second pulley 40
l1: Length (end amount) of the endless belt 26 sent out by the first pulley 30
l2: Length of the endless belt 26 delivered by the second pulley 30 (delivery amount)

In this case, when the motor 20 is rotationally driven by an angle ρ, the rotation angle θ1 of the first pulley 30 is equal to ρ, and the rotation angle θ2 of the second pulley 40 is equal to iρ. On the other hand, the length l1 of the endless belt 26 delivered by the first pulley 30 is equal to Rρ, and the length l2 of the endless belt 26 delivered by the second pulley 40 is equal to irρ. Therefore, if R <ir, the length l2 of the endless belt 26 sent out by the second pulley 40 is longer than the length 11 of the endless belt 26 sent out by the first pulley 30.

In FIG. 1, when the first pulley 30 is rotated counterclockwise (in the direction of the solid line), the endless belt 26 that reaches the second pulley 40 from the first pulley 30 via the fourth pulley 70. The length becomes shorter, and the fourth pulley 70 moves upward (in the direction of the solid line) in the drawing. Further, when the first pulley 30 is rotated counterclockwise (in the direction of the solid line), the second pulley 40 reaches the first pulley 30 via the fifth pulley 50 and the third pulley 60. The length of the endless belt 26 is increased. Since the position of the fifth pulley 50 is fixed, in this case, the third pulley 60 moves downward (in the direction of the solid line) in the drawing.

On the other hand, in FIG. 1, when the first pulley 30 is rotated clockwise (in the direction of the broken line), the endless belt 26 reaching the second pulley 40 from the first pulley 30 via the fourth pulley 70. And the fourth pulley 70 moves downward (in the direction of the broken line) in the figure. In addition, when the first pulley 30 is rotated clockwise (in the direction of the broken line), the endless belt reaches the first pulley 30 from the second pulley 40 via the fifth pulley 50 and the third pulley 60. The length of the belt 26 is shortened. Since the position of the fifth pulley 50 is fixed, in this case, the third pulley 60 moves upward (in the direction of the broken line) in the drawing.

At this time, in the case of the differential device 10 according to the present embodiment, since the diameter of each pulley and the horizontal distance between the pulleys are set appropriately, the direction of the endless belt 26 located between the pulleys does not change. The third pulley 60 and the fourth pulley 70 move linearly. That is, the endless belt 26 between the second pulley 40 and the fourth pulley 70 and the endless belt 26 between the first pulley 30 and the fourth pulley 70 have a diameter of the fourth pulley 70. The fourth pulley 70 linearly moves without changing the direction of the endless belts 26 while maintaining the same width as that of the endless belt 26. Similarly, the endless belt 26 between the first pulley 30 and the third pulley 60 and the endless belt 26 between the fifth pulley 50 and the third pulley 60 are connected to the third pulley 60. The third pulley 60 moves in a straight line without changing the direction of the endless belts 26 while maintaining the same width as the diameter and arranged in parallel. The third pulley 60 and the fourth pulley 70 have their linear motion directions determined by guide portions (not shown).

Thereby, the rectilinear movement distances of the third pulley 60 and the fourth pulley 70 with respect to the rotation angle of the motor 20 change proportionally, and control of the rectilinear movement of the third pulley 60 and the fourth pulley 70 can be easily performed. Become. In particular, when the diameter of the third pulley 60 and the diameter of the fourth pulley 70 are equal, the third pulley 60 and the fourth pulley 70 are opposite to each other with respect to a certain rotation angle of the motor 20. , And can be moved at equal distances.

As described above, the differential device 10 can convert the rotational motion of the motor 20 into the linear motion of the third pulley 60 and the fourth pulley 70. When the diameter of the first pulley 30 and the diameter of the second pulley 40 are the same, the smaller the difference in rotational speed, the longer the length of the endless belt 26 delivered by the first pulley 30 and the second pulley 40. A difference from the length of the fed endless belt 26 is reduced. Accordingly, the smaller the difference in rotational speed between the first pulley 30 and the second pulley 40, the smaller the straight travel distance of the third pulley 60 and the fourth pulley 70.

In the case of the differential device 10 shown in FIG. 1, if the radius of the second pulley 40 and the radius of the fifth pulley 50 are the same, the linear travel distance of the third pulley 60 and the This is equal to the straight travel distance of the four pulleys 70. At this time, the rectilinear movement distance of the third pulley 60 and the fourth pulley 70 can be expressed by the following equation (1).
d = ρ (R−i · r) (1)
Therefore, the control device can proportionally control the straight travel distance d of the third pulley 60 and the fourth pulley 70 by controlling the rotation angle ρ of the motor 20.

(1-3. Application examples to human body-mounted robots)
Next, an example in which the differential device 10 according to the present embodiment is used as an actuator of the human body wearing robot 100 will be described with reference to FIG. FIG. 3 is an explanatory diagram showing an example of the human body-mounted robot 100 that is operated by the differential device 10.

3, the third pulley 60 and the fourth pulley 70 are connected to the other ends of the coil springs 14 and 16 each having one end fixed to the fixing portion 12. The other ends of the coil springs 14 and 16 are fixed to the rotation shafts of the third pulley 60 and the fourth pulley 70 and do not hinder the shaft rotation of the third pulley 60 and the fourth pulley 70. The ends of the cables 132 and 134 fixed to the joint 120 of the human body-mounted robot 100 are connected to the rotation shafts of the third pulley 60 and the fourth pulley 70, and the third pulley 60 and the fourth pulley 70 The pulley 70 is loaded on the opposite side to the biasing direction of the coil springs 14 and 16.

The illustrated human-body-mounted robot 100 includes a joint portion 120, and a first arm portion 112 and a second arm portion 114 that are coupled to be rotatable about the joint portion 120. The upper part of the first arm portion 112 is fixed to a mounting belt 102 that is wrapped around the waist of a human body. The lower portion of the second arm portion 114 is fixed to a mounting belt 104 that is wound around the thigh of the human body. For example, when the user walks, the joint 120 is rotated clockwise as shown in the figure, so that the second arm 114 is rotated clockwise around the joint 120 and the user raises the foot. Is assisted. The joint unit 120 is an example of a rotation operation unit that is rotationally driven by the differential device 10.

Specifically, when a control device (not shown) detects that the user is trying to raise his / her foot by using a myoelectric potential sensor or a sensor for detecting the movement of the user's foot, as shown in FIG. The motor 20 is driven to rotate counterclockwise. As a result, the fourth pulley 70 moves in a direction approaching the fixed portion 12 side and pulls the cable 132. If it does so, the joint part 120 will rotate clockwise and the cable 134 will be pulled by the joint part 120 side. At this time, since the third pulley 60 moves in a direction away from the fixed portion 12 side, the cable 134 moves to the joint portion 120 side. As a result, the second arm portion 114 rotates clockwise around the joint portion 120 to generate a force that assists the user in raising the foot.

On the contrary, when the user is going to step down, the control device drives the motor 20 to rotate clockwise. As a result, the third pulley 60 pulls the cable 134 this time, and the cable 132 also moves following the pulling of the cable 134 to rotate the joint portion 120 counterclockwise. Thereby, the force which assists the operation | movement which lowers a leg | foot by a user generate | occur | produces.

Since the differential device 10 according to the present embodiment can control the straight travel distances of the third pulley 60 and the fourth pulley 70 by the rotation of the motor 20 at equal distances, the joint portion 120 is rotated in any direction. However, slack does not occur in either one of the cables 132 and 134. Further, since the differential device 10 can proportionally control the linear movement distances of the third pulley 60 and the fourth pulley 70 in accordance with the rotation angle of the motor 20, it is easy to rotate the joint 120. Can be controlled.

As the cables 132 and 134 for connecting the differential device 10 and the joint portion 120 and rotating the joint portion 120, for example, a Bowden cable can be used. In this case, one end side of the protective covers 131 and 133 outside the cables 132 and 134 of the Bowden cable is fixed to the fixing unit 113 at a position different from the joint unit 120 in the human body wearing robot 100. In the example shown in FIG. 3, one end side of the protective covers 131 and 133 is fixed to the fixing portion 113 provided on the first arm portion 112, but may be fixed to the fixing portion of the mounting belt 102. Further, the other end sides of the protective covers 131 and 133 are fixed to the fixing portion 90 on the extension line of the linear movement of the third pulley 60 and the fourth pulley 70 of the differential device 10. By using the Bowden cable, the movement of the cables 132 and 134 passing through the inside of the protective covers 131 and 133 is restricted, and there is no direct contact with clothes or the body. Few.

Further, in the example of the human body wearing robot 100, the differential device 10 can be arranged at a position away from the joint portion 120. For example, the differential device 10 may be provided in the form of a backpack or the like that the user carries on the back, or may be provided in the form of a hand-held or self-propelled cart.

(1-4. Summary)
As described above, since the differential device 10 according to the first embodiment can arrange the endless transmission member on substantially the same plane, the endless transmission member is hardly twisted, An endless belt 26 or an endless chain can be used as the endless transmission member. Therefore, it is possible to improve the service life of the endless transmission member without increasing the size of components such as pulleys, and to withstand continuous use.

In addition to the motor 20, the differential device 10 according to the present embodiment can be mainly composed of five pulleys, two gears, and an endless belt 26. Therefore, the manufacturing cost can be reduced. Further, since there is only one meshing of gears, there is little backlash, responsiveness can be improved, and operating noise and impact can be reduced.

In addition, the differential device 10 according to the present embodiment can connect the third pulley 60 and the fourth pulley 70 to a rotation operation unit such as the joint unit 120 of the human body wearing robot 100 via a cable. Therefore, the differential device 10 can be installed or arranged at a position away from the operation target, and the degree of freedom of the arrangement position of the differential device 10 is increased.

Further, in the differential device 10 according to the present embodiment, the linear travel distances of the third pulley 60 and the fourth pulley 70 due to the rotation of the motor 20 are equal. Further, the differential device 10 according to the present embodiment can proportionally control the straight travel distances of the third pulley 60 and the fourth pulley 70 according to the rotation angle of the motor 20. Therefore, it is possible to easily control the rotation operation unit such as the joint unit 120 of the human body-mounted robot 100.

The number of teeth of the drive gear 32 and the driven gear 42 may be reversed. In this case, the relationship between the rotation direction of the motor 20 and the direction of the linear movement of the third pulley 60 and the fourth pulley 70 is reversed. Further, the motor 20 may rotate the second pulley 40 instead of the first pulley 30.

Further, when it is desired to make the linear movement distance of the third pulley 60 different from the linear movement distance of the fourth pulley 70, the radius of the third pulley 60 and the fourth pulley 70 are determined according to the ratio or the like. The radius may be different.

<2. Second Embodiment>
Next, a differential device 150 according to the second exemplary embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic view of the main part of the differential device 150 as viewed along the extending direction of the rotation shaft of each pulley, and FIG. 5 is a perspective view of the main part of the differential device 150.

The differential device 150 includes a first pulley 162, a second pulley 164, a third pulley 166, and a fourth pulley 168. Further, the differential device 150 includes a motor 20 as a drive unit that rotates the first pulley 162, a first pulley 162, a second pulley 164, a third pulley 166, and a fourth pulley 168. And an endless belt 172 as an endless transmission member disposed across. The motor 20 and the endless belt 172 may be the same as the motor 20 and the endless belt 26 according to the first embodiment.

The first pulley 162, the second pulley 164, the third pulley 166, and the fourth pulley 168 each have a rotation axis along the axial direction of the rotation shaft 24 of the motor 20. The first pulley 162, the second pulley 164, the third pulley 166, and the fourth pulley 168 are each provided with an endless belt 172 on the circumferential surface. The endless belt 172 is wound around the first pulley 162, the fourth pulley 168, the second pulley 164, and the third pulley 166 in this order, and is wound around the first pulley 162 again. The peripheral surfaces of the first pulley 162, the fourth pulley 168, the second pulley 164, and the third pulley 166 are located on a plane orthogonal to the rotation shaft 24 of the motor 20, and the endless belt 172 is It is wound and arranged on a plane.

The first pulley 162 is connected to the rotating shaft 24 of the motor 20 and rotates about the rotating shaft 24. The second pulley 164 is rotatably supported with respect to a fixed portion (not shown). In the differential device 150 according to the present embodiment, the radius R of the second pulley 164 is smaller than the radius r of the first pulley 162. The third pulley 166 and the fourth pulley 168 have the same diameter, and are supported by the endless belt 172 so as to be rotatable. The third pulley 166 and the fourth pulley 168 are each supported so as to be able to advance and retract along a predetermined direction. For example, the third pulley 166 and the fourth pulley 168 are urged upward by a coil spring whose one end is fixed to a fixing portion (not shown) on the upper side in the drawing, and a load is applied to the lower side in the drawing. It may come to be.

Further, the differential device 150 according to the present embodiment includes a rotation shaft of the motor 20, that is, a fifth pulley 152 fixed to the rotation shaft of the first pulley 162 and a rotation shaft 25 of the second pulley 164. And a fixed sixth pulley 154. The fifth pulley 152 can rotate about the rotation shaft 24, and the sixth pulley 154 can rotate about the rotation shaft 25. An endless belt 172 as a second endless transmission member is wound around the fifth pulley 152 and the sixth pulley 154. The peripheral surface of the fifth pulley 152 and the peripheral surface of the sixth pulley 154 are located on the same plane, and the endless belt 172 is disposed on the plane. Therefore, the endless belt 172 or the endless chain can be used as the second endless transmission member. However, the second endless transmission member may be an endless cable.

In the differential device 150 according to the present embodiment, the fifth pulley 152 and the sixth pulley 154 have the same radius. Accordingly, when the motor 20 is driven to rotate, the fifth pulley 152 and the sixth pulley 154 rotate at the same speed. Therefore, the first pulley 162 and the second pulley 164 rotate at the same speed. However, the radius r of the second pulley 164 is smaller than the radius R of the first pulley 162. As a result, when the first pulley 162 and the second pulley 164 rotate at the same speed, the length of the endless belt 172 sent out by the first pulley 162 is sent out by the second pulley 164. It becomes longer than the length of the endless belt 172.

In FIG. 4, when the first pulley 162 is rotated clockwise (in the direction of the solid line), the length of the endless belt 172 from the first pulley 162 to the second pulley 164 via the third pulley 166. The third pulley 166 moves downward (in the direction of the solid line) in the drawing. In addition, when the first pulley 162 is rotated clockwise (in the direction of the solid line), the length of the endless belt 172 from the second pulley 164 to the first pulley 162 via the fourth pulley 168 is increased. The fourth pulley 168 moves upward (in the direction of the solid line) in the drawing.

On the other hand, in FIG. 4, when the first pulley 162 is rotated counterclockwise (in the direction of the broken line), the endless belt reaches the second pulley 164 from the first pulley 162 via the third pulley 166. The length of 172 becomes shorter, and the third pulley 166 moves upward (in the direction of the broken line) in the figure. Further, when the first pulley 162 is rotated counterclockwise (in the direction of the broken line), the length of the endless belt 172 from the second pulley 164 to the first pulley 162 via the fourth pulley 168 Becomes longer, and the fourth pulley 168 moves downward (in the direction of the broken line) in the figure.

At this time, in the example shown in FIG. 4, when the fourth pulley 168 moves straight, the position of the endless belt 172 changes. That is, the endless belt 172 between the first pulley 162 and the fourth pulley 168 and the endless belt 172 between the second pulley 164 and the fourth pulley 168 are not arranged in parallel. Therefore, the direction of the endless belt 172 can change with the straight movement of the fourth pulley 168. Therefore, the linear travel distance of the fourth pulley 168 with respect to the rotation angle of the motor 20 does not change proportionally. On the other hand, the endless belt 172 between the first pulley 162 and the third pulley 166 and the endless belt 172 between the second pulley 164 and the third pulley 166 have a diameter of the third pulley 166. The third pulley 166 moves in a straight line without changing the direction of the endless belts 172, while maintaining the same width as that of the endless belt 172. Therefore, the linear travel distance of the third pulley 166 with respect to the rotation angle of the motor 20 changes proportionally. The third pulley 166 and the fourth pulley 168 have their linear motion directions determined by guide portions (not shown).

Thus, the differential device 150 can convert the rotational motion of the motor 20 into the linear motion of the third pulley 166 and the fourth pulley 168. At this time, the straight travel distance of the third pulley 166 and the fourth pulley 168 can be expressed by the above equation (1). In the differential device 10 according to the present embodiment, the diameter of the fourth pulley 168 is matched with the sum of the diameter of the first pulley 162, the diameter of the second pulley 164, and the diameter of the third pulley 166. As a result, the linear travel distances of the third pulley 166 and the fourth pulley 168 can be proportionally controlled according to the rotation angle of the motor 20.

The differential device 150 according to the present embodiment can also be applied as an actuator of the human body-mounted robot 100 in the same manner as the differential device 10 according to the first embodiment.

As described above, since the differential device 150 according to the second embodiment can arrange the endless transmission member on substantially the same plane, the endless transmission member is hardly twisted, An endless belt 172 or an endless chain can be used as the endless transmission member. Further, the fifth pulley 152 and the endless transmission member wound around the sixth pulley 154 for transmitting the rotation of the motor 20 to the second pulley 164 may also be arranged on substantially the same plane. Therefore, the endless transmission member is hardly twisted, and the endless belt 172 and the endless chain can be used as the endless transmission member. Therefore, it is possible to improve the service life of the endless transmission member without increasing the size of components such as pulleys, and to withstand continuous use.

In addition to the motor 20, the differential device 150 according to the present embodiment can be mainly composed of six pulleys and endless belts 172 and 174. Therefore, a gear that requires high machining accuracy is not required, and the manufacturing cost can be reduced. Further, since the differential device 150 does not mesh with the gear, there is no backlash, the responsiveness can be improved, and the operating sound and impact can be reduced.

In addition, the differential device 150 according to the present embodiment can connect the third pulley 166 and the fourth pulley 168 to an operation target such as the joint 120 of the human body-mounted robot 100 via a cable. Therefore, the differential device 150 can be installed or arranged at a position away from the operation target, and the degree of freedom of the arrangement position of the differential device 150 is increased.

In the differential device 150 according to the present embodiment, the diameter of the fourth pulley 168 is set to the sum of the diameter of the first pulley 162, the diameter of the second pulley 164, and the diameter of the third pulley 166. In the case of matching, the linear travel distances of the third pulley 166 and the fourth pulley 168 due to the rotation of the motor 20 become equal distances. The diameter of the fourth pulley 168 is adjusted to the sum of the diameter of the first pulley 162, the diameter of the second pulley 164, and the diameter of the third pulley 166, and the horizontal distance between the pulleys is appropriately set. When set, the direction of the endless belt 172 does not change as the fourth pulley 168 moves straight. Therefore, the straight travel distances of the third pulley 166 and the fourth pulley 168 can be proportionally controlled according to the rotation angle of the motor 20. Therefore, it is possible to easily control the rotation operation unit such as the joint unit 120 of the human body-mounted robot 100.

In the differential device 150 according to the present embodiment as well, when it is desired to make the rectilinear travel distance of the third pulley 166 different from the rectilinear travel distance of the fourth pulley 168, the first pulley 166 varies depending on the ratio or the like. The radius of the third pulley 166 and the radius of the fourth pulley 168 may be different.

<3. Third Embodiment>
Next, a differential device 200 according to the third embodiment will be described with reference to FIG. FIG. 6 is a schematic view of the main part of the differential device 200 as viewed along the extending direction of the rotation shaft of each pulley.

The differential device 200 includes a first pulley 220, a second pulley 230, a third pulley 240, and a fourth pulley 245. In addition, the differential device 200 includes a motor (not shown) as a drive unit that rotates the first pulley 220, a first pulley 220, a second pulley 230, a third pulley 240, and a fourth pulley. And an endless belt 212 as an endless transmission member disposed over 245. As the motor and endless belt 212, the same motor 20 and endless belt 26 according to the first embodiment can be used.

The first pulley 220, the second pulley 230, the third pulley 240, and the fourth pulley 245 each have a rotation axis along the axial direction of the rotation axis of the motor. The first pulley 220, the second pulley 230, the third pulley 240, and the fourth pulley 245 are each provided with an endless belt 212 on the circumferential surface. The endless belt 212 is wound around the first pulley 220, the third pulley 240, the second pulley 230, and the fourth pulley 245 in this order, and is wound around the first pulley 220 again. The peripheral surfaces of the first pulley 220, the second pulley 230, the third pulley 240, and the fourth pulley 245 are located on a plane orthogonal to the rotation axis of the motor, and the endless belt 212 is the plane. It is wound and arranged on the top.

The first pulley 220 is connected to the rotating shaft of the motor and rotates about the rotating shaft. The first pulley 220 is provided with a drive gear 222 that rotates in the same manner as the shaft of the first pulley 220 rotates. In addition, the second pulley 230 is provided with a driven gear 232 that similarly rotates along with the shaft rotation of the second pulley 230. The second pulley 230 and the driven gear 232 are rotatably supported with respect to a fixed portion (not shown). The driven gear 232 meshes with the drive gear 222. When the first pulley 220 is rotated by the motor, the rotation is transmitted to the second pulley 230 via the drive gear 222 and the driven gear 232, The second pulley 230 rotates on the axis. In the illustrated example, the number of teeth of the drive gear 222 is greater than the number of teeth of the driven gear 232. Therefore, the rotational speed of the second pulley 230 is faster than the rotational speed of the first pulley 220.

Note that a timing belt may be used instead of the drive gear 222 and the driven gear 232.

The third pulley 240 and the fourth pulley 245 have the same diameter and are rotatably supported by the endless belt 212. The third pulley 240 and the fourth pulley 245 are each supported so as to be able to advance and retract along a predetermined direction. For example, the third pulley 240 and the fourth pulley 245 are biased upward by a coil spring whose one end is fixed to a fixing portion (not shown) on the upper side in the drawing, and a load is applied to the lower side in the drawing. It may come to be.

In the differential device 200 according to the present embodiment, the radius R of the first pulley 220 is equal to the sum of the radius r of the second pulley 230, the radius of the third pulley 240, and the radius of the fourth pulley 245. ing. Further, the second pulley 230, the third pulley 240, and the fourth pulley 245 are arranged so as not to overlap in the illustrated vertical direction. Accordingly, the endless belt 212 disposed between the pulleys is all disposed along the vertical direction shown in the figure. Thereby, the frictional force between the endless belt 212 and each pulley is prevented from becoming excessive. In addition, when the third pulley 240 and the fourth pulley 245 move linearly, the position of the endless belt 212 does not change.

In the differential device 200 according to the present embodiment, since the radius R of the first pulley 220 is significantly larger than the radius r of the second pulley 230, the first pulley 220 is sent by the first pulley 220 when the motor is driven to rotate. The length of the endless belt 212 is longer than the length of the endless belt 212 delivered by the second pulley 230. However, the second pulley 230 is configured to rotate faster than the first pulley 220 so that the delivery length of the endless belt 212 is not greatly different.

In FIG. 6, when the first pulley 220 is rotated clockwise (in the direction of the solid line), the length of the endless belt 212 extending from the first pulley 220 to the second pulley 230 via the third pulley 240. The third pulley 240 moves downward (in the direction of the solid line) in the drawing. Further, when the first pulley 220 is rotated clockwise (in the direction of the solid line), the length of the endless belt 212 from the second pulley 230 to the first pulley 220 via the fourth pulley 245 is the length of the endless belt 212. The fourth pulley 245 moves upward (in the direction of the solid line) in the drawing.

On the other hand, in FIG. 6, when the first pulley 220 is rotated counterclockwise (in the direction of the broken line), the endless belt reaches the second pulley 230 from the first pulley 220 via the third pulley 240. The length 212 is shortened, and the third pulley 240 moves upward (in the direction of the broken line) in the figure. In addition, when the first pulley 220 is rotated counterclockwise (in the direction of the broken line), the length of the endless belt 212 from the second pulley 230 to the first pulley 220 via the fourth pulley 245. Becomes longer, and the fourth pulley 245 moves downward (in the direction of the broken line) in the figure.

In the example shown in FIG. 6, when the third pulley 240 and the fourth pulley 245 move linearly, the position of the endless belt 212 does not change. Therefore, the third pulley 240 and the fourth pulley 245 with respect to the rotation angle of the motor. The straight travel distance of the pulley 245 changes proportionally, and the straight motion of the third pulley 240 and the fourth pulley 245 can be easily controlled. In particular, when the diameter of the third pulley 240 and the diameter of the fourth pulley 245 are equal, the third pulley 240 and the fourth pulley 245 are opposite to each other with respect to a certain rotation angle of the motor. It can be moved at an equal distance. The third pulley 240 and the fourth pulley 245 are determined in the direction of straight movement by a guide portion (not shown).

Thus, the differential device 200 can convert the rotational motion of the motor into the linear motion of the third pulley 240 and the fourth pulley 245. At this time, the straight travel distance of the third pulley 240 and the fourth pulley 245 can be expressed by the above equation (1). Therefore, the control device can proportionally control the straight travel distance d of the third pulley 240 and the fourth pulley 245 according to the rotation angle of the motor.

The differential device 200 according to the present embodiment can also be applied as an actuator of the human body-mounted robot 100, similarly to the differential device 10 according to the first embodiment.

As described above, since the differential device 200 according to the third embodiment can dispose the endless transmission member on substantially the same plane, the endless transmission member is hardly twisted, An endless belt 212 or an endless chain can be used as the endless transmission member. Therefore, it is possible to improve the service life of the endless transmission member without increasing the size of components such as pulleys, and to withstand continuous use.

In addition to the motor, the differential device 200 according to the present embodiment can be mainly composed of four pulleys, two gears, and an endless belt 212. Therefore, the manufacturing cost can be reduced. Further, since the differential device 200 has only one gear meshing, it can reduce backlash, improve responsiveness, and reduce operating noise and impact.

Further, the differential device 200 according to the present embodiment can connect the third pulley 240 and the fourth pulley 245 to an operation target such as the joint 120 of the human body wearing robot 100 via a cable. Therefore, the differential device 200 can be installed or arranged at a position away from the operation target, and the degree of freedom of the arrangement position of the differential device 200 is increased.

Further, in the differential device 200 according to the present embodiment, the straight travel distances of the third pulley 240 and the fourth pulley 245 by the rotation of the motor are equal. Further, the differential device 200 according to the present embodiment can proportionally control the straight travel distances of the third pulley 240 and the fourth pulley 245 according to the rotation angle of the motor. Therefore, it is possible to easily control the rotation operation unit such as the joint unit 120 of the human body-mounted robot 100.

Also in the differential device 200 according to the present embodiment, when it is desired to make the rectilinear movement distance of the third pulley 240 different from the rectilinear movement distance of the fourth pulley 245, the first pulley 240 is moved in accordance with the ratio or the like. The radius of the third pulley 240 may be different from the radius of the fourth pulley 245.

<4. Fourth Embodiment>
Next, a differential device 250 according to a fourth embodiment will be described with reference to FIG. FIG. 7 is a schematic view of the main part of the differential device 250 as viewed along the extending direction of the rotation shaft of each pulley.

The differential device 250 includes a first pulley 260, a second pulley 270, a third pulley 280, and a fourth pulley 290. Further, the differential device 250 according to the present embodiment includes a first motor 254 as a drive unit that rotates the first pulley 260 and a second motor as a drive unit that rotates the second pulley 270. 256, and an endless belt 252 as an endless transmission member disposed across the first pulley 260, the second pulley 270, the third pulley 280, and the fourth pulley 290. As the first motor 254, the second motor 256, and the endless belt 252, the same motors as the motor 20 and the endless belt 26 according to the first embodiment can be used.

The first pulley 260, the second pulley 270, the third pulley 280, and the fourth pulley 290 each have a rotation axis along the axial direction of the rotation axis of the first motor 254 and the second motor 256, respectively. Have. The first pulley 260, the second pulley 270, the third pulley 280, and the fourth pulley 290 are each provided with an endless belt 252 on the circumferential surface. The endless belt 252 is wound around the first pulley 260, the fourth pulley 290, the second pulley 270, and the third pulley 280 in this order, and is wound around the first pulley 260 again. The peripheral surfaces of the first pulley 260, the fourth pulley 290, the second pulley 270, and the third pulley 280 are positioned on a plane orthogonal to the rotation axes of the first motor 254 and the second motor 256. The endless belt 252 is wound around the plane.

The first pulley 260 is connected to the rotation shaft of the first motor 254 and rotates about the rotation shaft. The second pulley 270 is connected to the rotation shaft of the second motor 256 and rotates about the rotation shaft. In the differential device 250 according to the present embodiment, the radius R of the first pulley 260 and the radius r of the second pulley 270 are the same. The third pulley 280 and the fourth pulley 290 have the same diameter, and are supported by the endless belt 252 so as to be rotatable. The third pulley 280 and the fourth pulley 290 are each supported so as to be able to advance and retract along a predetermined direction. For example, the third pulley 280 and the fourth pulley 290 are urged in the direction of the rotation axis of the first pulley 260 in the figure by a coil spring having one end fixed to a fixing portion (not shown), and opposite to each other. A load may be applied in the direction.

In the differential device 250 according to the present embodiment, the first motor 254 is driven at a higher rotational speed than the second motor 256. Thereby, the length of the endless belt 252 delivered by the first pulley 260 is longer than the length of the endless belt 252 delivered by the second pulley 270.

In FIG. 7, when the first pulley 260 is rotated clockwise (in the direction of the solid line), the length of the endless belt 252 from the first pulley 260 to the second pulley 270 via the third pulley 280. The third pulley 280 moves downward (in the direction of the solid line) in the figure. Further, when the first pulley 260 is rotated clockwise (in the direction of the solid line), the length of the endless belt 252 from the second pulley 270 to the first pulley 260 via the fourth pulley 290 is the length of the endless belt 252. The fourth pulley 290 is shortened and moves upward (in the direction of the solid line) in the drawing.

On the other hand, in FIG. 7, when the first pulley 260 is rotated counterclockwise (in the direction of the broken line), the endless belt reaches the second pulley 270 from the first pulley 260 via the third pulley 280. The length of 252 is shortened, and the third pulley 280 moves upward (in the direction of the broken line) in the figure. Further, when the first pulley 260 is rotated counterclockwise (in the direction of the broken line), the length of the endless belt 252 from the second pulley 270 to the first pulley 260 via the fourth pulley 290. Becomes longer, and the fourth pulley 290 moves downward (in the direction of the broken line) in the figure.

In the example shown in FIG. 7, when the third pulley 280 and the fourth pulley 290 move linearly, the rotation angle of the first motor 254 and the second motor 256 is not changed because the position of the endless belt 252 does not change. The linear movement distances of the third pulley 280 and the fourth pulley 290 with respect to the above change proportionally, and the linear movement of the third pulley 280 and the fourth pulley 290 can be easily controlled. In particular, when the diameter of the third pulley 280 and the diameter of the fourth pulley 290 are equal, the third pulley 280 and the second pulley 280 with respect to a certain rotation angle of the first motor 254 and the second motor 256. The four pulleys 290 can be moved at equal distances in opposite directions. The third pulley 280 and the fourth pulley 290 have their linear motion directions determined by guide portions (not shown).

Thus, the differential device 250 can convert the rotational motions of the first motor 254 and the second motor 256 into the linear motions of the third pulley 280 and the fourth pulley 290. At this time, the rectilinear movement distances of the third pulley 280 and the fourth pulley 290 can be expressed by the above equation (1). Therefore, the control device can proportionally control the straight travel distance d of the third pulley 280 and the fourth pulley 290 according to the rotation angles of the first motor 254 and the second motor 256.

The differential device 250 according to the present embodiment can also be applied as an actuator of the human body-mounted robot 100, similarly to the differential device 10 according to the first embodiment.

As described above, since the differential device 250 according to the fourth embodiment can arrange the endless transmission member on substantially the same plane, the endless transmission member is hardly twisted, An endless belt 252 or an endless chain can be used as the endless transmission member. Therefore, it is possible to improve the service life of the endless transmission member without increasing the size of components such as pulleys, and to withstand continuous use. In particular, the differential device 250 according to the present embodiment can be configured using pulleys having the same diameter.

Further, the differential device 250 according to the present embodiment can be mainly configured by four pulleys and an endless belt 252 in addition to the first motor 254 and the second motor 256. Therefore, the manufacturing cost can be reduced. Further, since the differential device 250 has no gear meshing, there is no backlash, the responsiveness can be improved, and the operating noise and impact can be reduced.

In addition, the differential device 250 according to the present embodiment can connect the third pulley 280 and the fourth pulley 290 to an operation target such as the joint 120 of the human body-mounted robot 100 via a cable. Therefore, the differential device 250 can be installed or arranged at a position away from the operation target, and the degree of freedom of the arrangement position of the differential device 250 is increased.

Further, in the differential device 250 according to the present embodiment, the linear travel distances of the third pulley 280 and the fourth pulley 290 due to the rotation of the first motor 254 and the second motor 256 are equal. Further, the differential device 250 according to the present embodiment can proportionally control the straight travel distances of the third pulley 280 and the fourth pulley 290 according to the rotation angle of the motor. Therefore, it is possible to easily control the rotation operation unit such as the joint unit 120 of the human body-mounted robot 100.

In the differential device 250 according to the present embodiment as well, when it is desired to make the rectilinear movement distance of the third pulley 280 different from the rectilinear movement distance of the fourth pulley 290, the first pulley 290 is changed according to the ratio or the like. The radius of the third pulley 280 may be different from the radius of the fourth pulley 290.

<5. Fifth embodiment>
Next, with reference to FIG. 8, the differential gear 300 concerning 5th Embodiment is demonstrated. FIG. 8 is a perspective view of a main part of the differential device 300.

The differential device 300 includes a first pulley 312, a second pulley 314, a third pulley 316, and a fourth pulley 318. In addition, the differential device 300 includes a motor 20 as a driving unit that rotates the first pulley 312, a first pulley 312, a second pulley 314, a third pulley 316, and a fourth pulley 318. And an endless belt 322 as an endless transmission member disposed across. The motor 20 and the endless belt 322 may be the same as the motor 20 and the endless belt 26 according to the first embodiment.

The first pulley 312, the second pulley 314, the third pulley 316, and the fourth pulley 318 each have a rotation axis along the axial direction of the rotation shaft 24 of the motor 20. The first pulley 312, the second pulley 314, the third pulley 316, and the fourth pulley 318 are each provided with an endless belt 322 on the circumferential surface. The endless belt 322 is wound around the first pulley 312, the fourth pulley 318, the second pulley 314, and the third pulley 316 in this order, and is wound around the first pulley 312 again.

In the differential device 300 according to the present embodiment, the first pulley 312 is a driving pulley, the second pulley 314 is a driven pulley, and the differential device 300 includes the first pulley 312 and the second pulley. A continuously variable transmission (not shown) that changes the pitch diameter of at least one of the pulleys 314 is provided. Accordingly, the radius of curvature of the endless belt 322 wound around the first pulley 312 and the second pulley 314 can be freely adjusted. In the example shown in FIG. 8, the radius of curvature of the endless belt 322 wound on the second pulley 314 is made smaller than the radius of curvature of the endless belt 322 wound on the first pulley 312.

The third pulley 316 and the fourth pulley 318 are supported by an endless belt 322 so as to be rotatable. The third pulley 316 and the fourth pulley 318 are each supported so as to be able to advance and retract along a predetermined direction. For example, the third pulley 316 and the fourth pulley 318 are urged upward by a coil spring whose one end is fixed to a fixing portion (not shown) on the upper side in the drawing, and a load is applied to the lower side in the drawing. It may come to be.

Also in the differential device 300 according to the present embodiment, the disposition position of the endless belt 322 on the first pulley 312 and the second pulley 314 and the peripheral surfaces of the third pulley 316 and the fourth pulley 318 are as follows. The endless belt 322 is disposed on a plane perpendicular to the rotation shaft 24 of the motor 20 and is wound around the plane.

Further, the differential device 300 according to the present embodiment includes a rotation shaft 24 of the motor 20, that is, a fifth pulley 332 fixed to the rotation shaft of the first pulley 312 and a rotation shaft 25 of the second pulley 314. And a sixth pulley 334 fixed to the head. The fifth pulley 332 can rotate about the rotation shaft 24, and the sixth pulley 334 can rotate about the rotation shaft 25. An endless belt 324 as a second endless transmission member is wound around the fifth pulley 332 and the sixth pulley 334. The peripheral surface of the fifth pulley 332 and the peripheral surface of the sixth pulley 334 are located on the same plane, and an endless belt 324 is disposed on the plane.

In the differential device 300 according to the present embodiment, the fifth pulley 332 and the sixth pulley 334 have the same radius. Therefore, when the motor 20 is driven to rotate, the fifth pulley 332 and the sixth pulley 334 rotate at the same speed. Therefore, the first pulley 312 and the second pulley 314 rotate at the same speed. However, the pitch diameter of the first pulley 312 and the pitch diameter of the second pulley 314 are different depending on the continuously variable transmission. As a result, when the first pulley 312 and the second pulley 314 rotate at the same speed, the length of the endless belt 322 sent out by the first pulley 312 is sent out by the second pulley 314. It becomes longer than the length of the endless belt 322. Therefore, by rotating the motor 20 in either direction, the third pulley 316 and the fourth pulley 318 can be linearly moved in directions opposite to each other. The third pulley 316 and the fourth pulley 318 are determined in the direction of straight movement along a guide portion (not shown).

As described above, the differential device 300 can convert the rotational motion of the motor 20 into the linear motion of the third pulley 316 and the fourth pulley 318. At this time, the straight travel distance of the third pulley 316 and the fourth pulley 318 can be expressed by the above equation (1). Therefore, the control device sets the pitch diameter and the rotation angle of the first pulley 312 and the second pulley 314 according to the straight travel distance d of the third pulley 316 and the fourth pulley 318, and sets the motor 20 Control to rotate can be executed.

The differential device 300 according to the present embodiment can also be applied as an actuator of the human body wearing robot 100 in the same manner as the differential device 10 according to the first embodiment.

As explained above, since the differential device 300 according to the fifth embodiment can arrange the endless transmission member on substantially the same plane, the endless transmission member is hardly twisted, An endless belt 322 or an endless chain can be used as the endless transmission member. Further, the endless transmission member wound around the fifth pulley 332 and the sixth pulley 334 for transmitting the rotation of the motor 20 to the second pulley 314 may also be disposed on substantially the same plane. Therefore, the endless transmission member is hardly twisted, and the endless belt 324 and the endless chain can be used as the endless transmission member. Therefore, it is possible to improve the service life of the endless transmission member without increasing the size of components such as pulleys, and to withstand continuous use.

Further, since the differential device 300 according to the present embodiment has no meshing of gears, there is no backlash, the responsiveness can be improved, and the operation sound and impact can be reduced. In addition, the differential device 300 according to the present embodiment can connect the third pulley 316 and the fourth pulley 318 to an operation target such as the joint 120 of the human body wearing robot 100 via a cable. Accordingly, the differential device 300 can be installed or arranged at a position away from the operation target, and the degree of freedom of the arrangement position of the differential device 300 is increased.

In the differential device 300 according to the present embodiment as well, when it is desired to make the rectilinear travel distance of the third pulley 316 and the rectilinear travel distance of the fourth pulley 318 different from each other, The radius of the third pulley 316 and the radius of the fourth pulley 318 may be different.

<6. Sixth Embodiment>
Next, a differential device 350 according to a ninth embodiment will be described with reference to FIG. FIG. 9 is a schematic view of the main part of the differential 350 as viewed along the extending direction of the rotation shaft of each pulley.

The differential device 350 includes a first pulley 360, a second pulley 370, a third pulley 380, and a fourth pulley 390. Further, the differential device 350 includes a motor 20 as a driving unit that rotates the first pulley 360, a first pulley 360, a second pulley 370, a third pulley 380, and a fourth pulley 390. And an endless belt 352 serving as an endless transmission member disposed across. As the motor 20 and the endless belt 352, those similar to the motor 20 and the endless belt 26 according to the first embodiment can be used.

The first pulley 360, the second pulley 370, the third pulley 380, and the fourth pulley 390 each have a rotation axis along the axial direction of the rotation axis of the motor 20. The first pulley 360, the second pulley 370, the third pulley 380, and the fourth pulley 390 are each provided with an endless belt 352 on the circumferential surface. The endless belt 352 is wound around the first pulley 360, the fourth pulley 390, the second pulley 370, and the third pulley 380 in this order, and is then wound around the first pulley 360 again. The peripheral surfaces of the first pulley 360, the fourth pulley 390, the second pulley 370, and the third pulley 380 are located on a plane orthogonal to the rotation axis of the motor 20, and the endless belt 352 It is wound and arranged on the top.

The first pulley 360 is connected to the rotating shaft of the motor 20 and rotates about the rotating shaft. The first pulley 360 is provided with a drive gear 362 that rotates in the same manner as the first pulley 360 rotates. The diameter of the second pulley 370 is larger than the diameter of the first pulley 360. The second pulley 370 is provided with a driven gear 372 that rotates in the same manner as the second pulley 370 rotates. The second pulley 370 and the driven gear 372 are rotatably supported with respect to a fixed portion (not shown). The driven gear 372 meshes with the driving gear 362, and when the first pulley 360 is rotated by the motor 20, the rotation is transmitted to the second pulley 370 via the driving gear 362 and the driven gear 372. The second pulley 370 rotates on the axis. In the illustrated example, the number of teeth of the drive gear 362 is equal to the number of teeth of the driven gear 372. Therefore, the rotation speed of the second pulley 370 is equal to the rotation speed of the first pulley 360.

Note that a timing belt may be used instead of the drive gear 362 and the driven gear 372.

The third pulley 380 and the fourth pulley 390 have the same diameter and are supported by an endless belt 352 so as to be rotatable. The third pulley 380 and the fourth pulley 390 are each supported so as to be able to advance and retract along a predetermined direction. For example, the third pulley 380 and the fourth pulley 390 are urged upward by a coil spring whose one end is fixed to a fixing portion (not shown) on the upper side in the drawing, and a load is applied to the lower side in the drawing. It may come to be.

In the differential device 350 according to the present embodiment, since the radius R of the first pulley 360 is smaller than the radius r of the second pulley 370, the first pulley 360 is sent out when the motor 20 is driven to rotate. The length of the endless belt 352 is shorter than the length of the endless belt 352 delivered by the second pulley 370.

In FIG. 9, when the first pulley 360 is rotated counterclockwise (in the direction of the solid line), the endless belt 352 extending from the first pulley 360 via the third pulley 380 to the second pulley 370 The length is increased, and the third pulley 380 moves downward (in the direction of the solid line) in the drawing. Further, when the first pulley 360 is rotated counterclockwise (in the direction of the solid line), the length of the endless belt 352 extending from the first pulley 360 to the second pulley 370 via the fourth pulley 390. Becomes shorter, and the fourth pulley 390 moves upward (in the direction of the solid line) in the figure.

On the other hand, in FIG. 9, when the first pulley 360 is rotated clockwise (in the direction of the broken line), the endless belt 352 from the first pulley 360 to the second pulley 370 via the third pulley 380. And the third pulley 380 moves upward (in the direction of the broken line) in the drawing. Further, when the first pulley 360 is rotated clockwise (in the direction of the broken line), the length of the endless belt 352 extending from the first pulley 360 to the second pulley 370 via the fourth pulley 390 is reduced. The length becomes longer, and the fourth pulley 390 moves downward (in the direction of the broken line) in the figure.

At this time, in the example shown in FIG. 9, the position of the endless belt 352 changes when the third pulley 380 and the fourth pulley 390 move linearly. That is, the endless belt 352 between the second pulley 370 and the fourth pulley 390 and the endless belt 352 between the first pulley 360 and the fourth pulley 390 are not arranged in parallel. Therefore, the position of the endless belt 352 can change with the straight movement of the fourth pulley 390. Further, the endless belt 352 between the first pulley 360 and the third pulley 380 and the endless belt 352 between the second pulley 370 and the third pulley 380 are not arranged in parallel. Therefore, the position of the endless belt 352 can change with the straight movement of the third pulley 380. Therefore, the straight travel distances of the third pulley 380 and the fourth pulley 390 with respect to the rotation angle of the motor 20 do not change proportionally. The third pulley 380 and the fourth pulley 390 are determined in the direction of straight movement along a guide portion (not shown).

Thus, in the differential device 350 according to the present embodiment, the rotational operation unit 120A connected to the third pulley 380 and the fourth pulley 390 via the cables 132 and 134 has a long diameter portion and a short diameter portion. It is said that. Rotating operation unit 120A has a major axis portion of the relatively long diameter _{R L,} and a short diameter portion of the relatively short diameter _{R S,} so long diameter portion is sandwiched between two cables 132, 134 Be placed. As a result, when the third pulley 380 and the fourth pulley 390 are linearly moved in opposite directions, the rotation operation unit 120A rotates and is connected to the descending third pulley 380 or the fourth pulley 390. When the long diameter portion pushes the cables 132 and 134, it is possible to prevent the cables 132 and 134 from being slackened.

The differential device 350 according to the present embodiment can also be applied as an actuator of the human body wearing robot 100 in the same manner as the differential device 10 according to the first embodiment.

As described above, since the differential gear 350 according to the sixth embodiment can dispose the endless transmission member on substantially the same plane, the endless transmission member is hardly twisted, An endless belt 352 or an endless chain can be used as the endless transmission member. Therefore, it is possible to improve the service life of the endless transmission member without increasing the size of components such as pulleys, and to withstand continuous use.

In addition to the motor 20, the differential device 350 according to the present embodiment can be mainly composed of four pulleys, two gears, and an endless belt 352. Therefore, the manufacturing cost can be reduced. Further, since the differential gear 350 has only one gear meshing, it can reduce backlash, improve responsiveness, and reduce operating noise and impact.

In addition, the differential device 350 according to the present embodiment can connect the third pulley 380 and the fourth pulley 390 to the rotation operation unit 120A such as a joint portion of the human body wearing robot 100 via a cable. Therefore, the differential device 350 can be installed or arranged at a position away from the operation target, and the degree of freedom of the arrangement position of the differential device 350 is increased.

Further, in the differential device 350 according to the present embodiment, the rotation operation unit 120A connected to the third pulley 380 and the fourth pulley 390 via the cables 132 and 134 has a shape having a long diameter portion and a short diameter portion. It has become. Therefore, even when the linear travel distances of the third pulley 380 and the fourth pulley 390 do not change proportionally with respect to the rotation angle of the motor 20, the cables 132 and 134 are prevented from being loosened, and the rotation operation is performed. The rotational operation of the unit 120A can be compensated.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

For example, in the above-described embodiments, the first pulley and the second pulley have different radii or rotational speeds, so that the feed length of the endless transmission member by the first pulley and the endless transmission by the second pulley are increased. Although the delivery length of the member is different, the present invention is not limited to such an example. You may vary both the radius and rotational speed of a 1st pulley and a 2nd pulley. In this case, the gear ratio can be adjusted more flexibly, and the straight travel distance can be easily controlled by driving the motor.

In each of the above embodiments, the pulley is used as the rotating body, but the present invention is not limited to such an example. For example, when an endless chain is used as the endless transmission member, a sprocket may be used as a rotating body instead of a pulley.

For example, in each of the above-described embodiments, the example in which the differential device is applied as an actuator of a human body-mounted robot has been described. However, a device to which the differential device of the present invention can be applied is not limited to such an example. The differential device can be applied to various mechanical devices as an actuator of an operating body that transmits forces directed in opposite directions.

Claims (14)

1. A first rotating body, a second rotating body, a third rotating body and a fourth rotating body each having a rotation axis extending in parallel along one direction;
   A drive unit for rotating at least the first rotating body;
   An endless transmission member disposed across the first rotating body, the second rotating body, the third rotating body, and the fourth rotating body on a plane intersecting the one direction; With
   A differential device in which the third rotating body and the fourth rotating body each move linearly by driving the driving unit.
2. The difference according to claim 1, wherein a sending amount of the endless transmission member by the first rotating body when the driving unit is driven is different from a sending amount of the endless transmission member by the second rotating body. Moving device.
3. The endless transmission member is wound around at least the first rotating body, the fourth rotating body, the second rotating body, and the third rotating body in this order, and again the first rotating body. Be wounded by
   When the length of the endless transmission member extending from the first rotating body to the second rotating body via the third rotating body is increased by driving the driving unit, the first rotating body While the length of the endless transmission member from the rotating body to the second rotating body via the fourth rotating body is shortened,
   When the length of the endless transmission member from the first rotating body to the second rotating body via the third rotating body is shortened, the first rotating body performs the fourth rotation. The differential device according to claim 1, wherein a length of the endless transmission member that reaches the second rotating body via a body is increased.
4. 4. The differential device according to claim 1, wherein when the driving unit is driven, the first rotating body and the second rotating body rotate at different speeds.
5. The differential device according to any one of claims 1 to 3, wherein a radius of the first rotating body and a radius of the second rotating body are different from each other.
6. The differential device according to any one of claims 1 to 5, further comprising at least one driven rotator for changing a trajectory of the endless transmission member.
7. A fifth rotating body fixed to the rotating shaft of the first rotating body, a sixth rotating body fixed to the rotating shaft of the second rotating body, the fifth rotating body, and the sixth A rotation transmission portion including a second endless transmission member wound around the rotating body of
   The differential device according to any one of claims 1 to 6, wherein the second rotating body rotates by receiving the rotation of the first rotating body via the rotation transmitting unit.
8. The differential device according to any one of claims 1 to 6, further comprising a second driving unit that rotationally drives the second rotating body.
9. The differential device according to any one of claims 1 to 4, wherein the second rotator is rotated by transmission of rotation of the first rotator via a gear mechanism.
10. The continuously variable transmission that changes the pitch diameter of at least one of the driving pulley and the driven pulley, wherein the first rotating body is a driving pulley and the second rotating body is a driven pulley. The differential device according to any one of claims 1 to 4, further comprising:
11. The differential device according to any one of claims 1 to 10, wherein the endless transmission member is an endless belt, an endless chain, or an endless cable.
12. The third rotating body and the fourth rotating body are each connected to a cable fixed or wound around a rotation operation unit, and the differential device rotates the rotation operation unit. 12. The differential device according to any one of items 11 to 11.
13. The differential device according to claim 12, wherein the rotation operation unit is a joint unit of a human body-mounted robot.
14. The rotation operation part has a long diameter part and a short diameter part, and when the rotation operation part rotates, the long diameter part is connected to the cable connected to the third rotation body or the fourth rotation body. The differential according to claim 12, wherein tension is applied to the formed cable.
    

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