CN209970773U

CN209970773U - Joint unit

Info

Publication number: CN209970773U
Application number: CN201790000934.2U
Authority: CN
Inventors: 外川圭司
Original assignee: Sony Interactive Entertainment Inc
Current assignee: Sony Interactive Entertainment Inc
Priority date: 2016-06-14
Filing date: 2017-06-13
Publication date: 2020-01-21
Anticipated expiration: 2027-06-13
Also published as: JP6659840B2; JPWO2017217415A1; WO2017217415A1

Abstract

The utility model provides a joint unit. The joint mechanism (Mj) allows the movement of the first operating arm (10) about the first axis (Ax1) and the movement of the first operating arm (10) about the second axis (Ax 2). The joint mechanism (Mj) has a first counter gear (1A) and a second counter gear (1B) which are independent from each other and are rotatable, and the combination of the rotation of the first counter gear (1A) and the rotation of the second counter gear (1B) enables the operation of a first operating arm (10) centered on a first axis (Ax1) and the operation of the first operating arm (10) centered on a second axis (Ax 2). The first drive mechanism (M1) and the second drive mechanism (M2) rotate the first counter gear (1A) and the second counter gear (1B), respectively. The first drive mechanism (M1) and the second drive mechanism (M2) are located in the same direction with respect to the joint mechanism (Mj). The joint mechanism (Mj) can realize a joint unit which can increase the operating force of the working arm and can be easily mounted on the robot.

Description

Joint unit

Technical Field

The present specification relates to a joint unit to be mounted on a robot or the like.

Background

As exemplified in japanese patent application laid-open No. 2000-237985, in many robots, an electric motor is used to move an arm. The working arm may be configured to move in a plurality of directions. For example, in a robot simulating a human or an animal, the working arm can move in the front-rear direction with respect to the trunk or move in the left-right direction with respect to the trunk. In order to be able to move the operating arm in both directions, the operating arm may be configured to have two shafts at joints of the operating arm so that the operating arm can rotate about each shaft.

SUMMERY OF THE UTILITY MODEL

Therefore, there is an actuator that can perform an operation centered on a first axis and an operation centered on a second axis orthogonal to the first axis by causing two electric motors to cooperate with each other. An example of the actuator includes: two gears which are independent and rotatable from each other, and electric motors which rotationally drive the two gears, respectively. Further, the operation centered on the first axis is realized by driving the two electric motors in the same direction, and the operation centered on the second axis is realized by driving the two electric motors in mutually opposite directions. With the above-described actuator, two electric motors can be used for each of the operation centered on the first axis and the operation centered on the second axis. Therefore, a large operating force can be obtained without using a large electric motor having a maximum torque.

When the actuator is applied to a working arm of a robot or the like that can be operated in two directions (for example, a front-rear direction and a left-right direction), the operating force of the working arm can be increased. However, due to the arrangement of the two electric motors, it is difficult to mount the actuator on a robot or the like. For example, when the two electric motors are positioned apart from each other, the overall size increases, and it may be difficult to mount the actuator on the robot.

A joint unit according to an embodiment disclosed in the present specification includes: the working arm and set up in the joint mechanism of working arm. The joint mechanism allows the movement of the working arm about a first axis and the movement of the working arm about a second axis intersecting the first axis. The joint mechanism has a first gear and a second gear which are independent of each other and rotatable, and combines the rotation of the first gear and the rotation of the second gear to realize the movement of the working arm about the first axis and the movement of the working arm about the second axis. Further, the joint unit includes: a first drive mechanism having a first electric motor and outputting a rotational force for rotating the first gear; and a second drive mechanism having a second electric motor and outputting a rotational force for rotating the second gear. The first drive mechanism and the second drive mechanism are both located in a first direction with respect to the joint mechanism.

According to this joint unit, since both the first drive mechanism and the second drive mechanism are positioned in the same direction with respect to the joint mechanism, the joint unit can be easily mounted on a device such as a robot. The rotational forces of the first electric motor and the second electric motor can be used in each of the operation of the working arm about the first axis and the operation of the working arm about the second axis, and therefore the operating force of the working arm can be increased.

Drawings

Fig. 1 is a perspective view of a joint unit according to an embodiment of the present invention.

Fig. 2 is a perspective view of the joint unit shown in fig. 1. In this figure the outer shell of the joint mechanism is removed.

Fig. 3 is a sectional view taken by a cutting surface shown by the line III-III of fig. 2.

Fig. 4 is a sectional view taken by the cutting surface shown by the line IV-IV shown in fig. 1.

Fig. 5 is a view obtained when the joint unit 100 is viewed in the direction indicated by the arrow V in fig. 1. In this figure the housing of the drive is removed.

Fig. 6 is a diagram showing a design in a case where two joint units are mounted on a device such as a robot.

Fig. 7 is an enlarged view of fig. 1.

Detailed Description

Next, an embodiment of the present invention will be described. Fig. 1 is a perspective view of a joint unit 100 as an example of the embodiment of the present invention. Fig. 2 is a perspective view of the joint unit 100, in which the housing 8 (see fig. 1) of the joint mechanism Mj is removed. Fig. 3 is a sectional view taken along line III-III of fig. 2. Fig. 4 is a cross-sectional view taken along line IV-IV of fig. 1. Fig. 5 is a view obtained when the joint unit 100 is viewed in the direction indicated by the arrow V in fig. 1. In fig. 5, the housing 7 (see fig. 1) that houses the drive mechanisms M1 and M2 is removed.

As shown in fig. 1 and 2, the joint unit 100 includes: the first arm 10, and a joint mechanism Mj (see fig. 2) provided at a base portion of the first arm 10. The joint mechanism Mj is configured to allow the movement (rotation) of the first operating arm 10 about the first axis line Ax1 shown in fig. 1 and the movement (rotation) of the first operating arm 10 about the second axis line Ax 2. In the example of the joint unit 100, the second working arm 20 is connected to an end of the first working arm 10. The second operating arm 20 is movable about a third axis Ax3 shown in fig. 1, for example. An electric motor (not shown) for moving the second arm 20 may be disposed on the first arm 10. As shown in fig. 1, the third axis Ax3 is, for example, an axis parallel to the first axis Ax1, but is not necessarily limited thereto.

As shown in fig. 3 and 4, the joint mechanism Mj includes a first counter gear 1A and a second counter gear 1B disposed to face each other. The first counter gear 1A and the second counter gear 1B are independent of each other and rotatable. Thus, the first counter gear 1A and the second counter gear 1B can rotate in the same direction or in opposite directions, for example. The first counter gear 1A and the second counter gear 1B are also rotatable in the same direction, for example, and rotate only at different displacements (angles) from each other. In addition, in a state where one of the first counter gear 1A and the second counter gear 1B is stopped, only the other can be rotated. The joint mechanism Mj combines the rotation of the first counter gear 1A and the rotation of the second gear 1B to realize the operation of the first operating arm 10 about the first axis Ax1 and the operation of the first operating arm 10 about the second axis Ax 2. The term "combined" as used herein means that a displacement corresponding to the sum of the rotational displacement of the first counter gear 1A and the rotational displacement of the second gear 1B is generated in the first operating arm 10, and when there is a difference between the rotational displacement of the first counter gear 1A and the rotational displacement of the second gear 1B, a displacement corresponding to the difference is generated in the first operating arm 10. For example, when the first counter gear 1A and the second counter gear 1B rotate in opposite directions to each other (when there is a difference in rotational displacement), the joint mechanism Mj moves the first operating arm 10 around the second axis Ax 2. When the first counter gear 1A and the second counter gear 1B rotate in the same direction, the joint mechanism Mj moves the first operating arm 10 about the first axis Ax 1. With this joint mechanism Mj, the rotational force of the first electric motor 3A (see fig. 1) and the rotational force of the second electric motor 3B (see fig. 1) described later can be used in each of the operation of the first operating arm 10 about the first axis Ax1 and the operation of the first operating arm 10 about the second axis Ax2, and therefore the operating force of the first operating arm 10 can be increased.

The specific structure of the joint mechanism Mj will be described in detail below. As shown in fig. 3 and 4, in the example of the joint unit 100, the first counter gear 1A and the second counter gear 1B are disposed on the first axis Ax1 (specifically, on the transmission shaft 7A described later) and are rotatable about the first axis Ax 1. In the example of the joint unit 100, the first counter gear 1A and the second counter gear 1B are bevel gears that face each other in the direction of the first axis Ax 1. The joint mechanism Mj has an output gear 31 disposed between the first counter gear 1A and the second counter gear 1B. The output gear 31 is also a bevel gear, and engages with the first counter gear 1A and the second counter gear 1B. The joint mechanism Mj further includes a support body 32 rotatable about the first axis Ax 1. The support body 32 supports the output gear 31, whereby the output gear 31 is rotatable between the first counter gear 1A and the second counter gear 1B. The rotational center line of the output gear 31 is the second axis Ax 2. In other words, the output gear 31 is rotatable about the second axis Ax 2. The output gear 31 is engaged with both the opposing

gears

1A and 1B, and the output gear 31 and the support body 32 are rotatable integrally with the opposing

gears

1A and 1B around the first axis Ax 1. Therefore, the direction of the second axis Ax2 changes with the rotation of the output gear 31 and the support body 32 around the first axis Ax 1. The first operating arm 10 has a coupling portion 11 at its base (see fig. 2 and 4). The connecting portion 11 is connected to the output gear 31 so as to be interlocked with the output gear 31. That is, when the output gear 31 rotates about the first axis line Ax1, the coupling portion 11 also rotates about the first axis line Ax1, and when the output gear 31 rotates about the second axis line Ax2, the coupling portion 11 also rotates about the second axis line Ax 2. Note that, as the counter gears 1A and 1B and the output gear 31, a face gear may be used instead of the bevel gear.

When the first counter gear 1A and the second counter gear 1B rotate only in the same direction and at the same angle about the first axis Ax1 (for example, when rotating in the direction indicated by the arrow R1 in fig. 2), the first counter gear 1A, the second counter gear 1B, the output gear 31, and the support body 32 rotate integrally about the first axis Ax 1. At this time, the rotation of the output gear 31 about the second axis Ax2 is not generated. Therefore, the first operating arm 10 rotates about the first axis Ax1 in the direction indicated by the arrow R1. That is, the joint mechanism Mj combines the rotation of the first counter gear 1A and the rotation of the second gear 1B, and moves the first operating arm 10 about the first axis Ax 1. The first operating arm 10 rotates about the first axis line Ax1 only by an angle (specifically, one-half of the sum of displacements) corresponding to the sum of the displacements of the first counter gear 1A and the second counter gear 1B.

On the other hand, when the first counter gear 1A and the second counter gear 1B rotate only by the same angle in mutually opposite directions, for example, when the first counter gear 1A rotates in the direction indicated by the arrow R1 in fig. 2 and the second counter gear 1B rotates in the direction indicated by the arrow R2 in fig. 2, the output gear 31 rotates about the second axis line Ax 2. At this time, the support body 32 does not rotate about the first axis Ax 1. As a result, the first operating arm 10 rotates about the second axis Ax 2. That is, the joint mechanism Mj converts the difference between the rotational displacement of the first counter gear 1A and the rotational displacement of the second gear 1B into the rotation of the output gear 31 about the second axis Ax2, and moves the first operating arm 10 about the second axis Ax2 by this conversion. The first operating arm 10 rotates about the second axis line Ax2 by an angle (specifically, one-half of the difference between the displacements) corresponding to the difference between the displacement of the first counter gear 1A and the displacement of the second counter gear 1B.

As will be described later in detail, the first counter gear 1A receives the rotational force (torque) of the first electric motor 3A (see fig. 3), and the second counter gear 1B receives the rotational force (torque) of the second electric motor 3B (see fig. 3). Therefore, when the joint mechanism Mj is used, the first operating arm 10 is operated about the respective axes Ax1, Ax2 by the rotational forces of both the first electric motor 3A and the second electric motor 3B.

As shown in fig. 4, in the example of the joint unit 100, the support body 32 is disposed between the first counter gear 1A and the second counter gear 1B. Thus, for example, the joint mechanism Mj can be reduced in size as compared with a configuration in which a support body for supporting the output gear 31 is disposed outside the counter gears 1A and 1B and the output gear 31. In the example of the joint unit 100, the support body 32 is located near the first axis Ax1 with respect to the output gear 31. The support body 32 has a shaft portion 32a protruding toward the output gear 31 in a direction orthogonal to the first axis Ax1 (direction of the second axis Ax 2). The output gear 31 is rotatably supported by the shaft portion 32 a. Instead of the example of the joint unit 100, the output gear 31 may have a shaft portion that protrudes toward the support 32 and is fitted into the support 32. A support 32 is disposed between a second portion 11b of the coupling portion 11 of the first operating arm 10, which will be described later, and the output gear 31.

The first counter gear 1A, the second counter gear 1B, and the support body 32 are disposed on a transmission shaft 7A described later. The support body 32 is independent from the transmission shaft 7A and is rotatable. For example, when the support body 32 rotates in the direction of the arrow R1 in fig. 2, the transmission shaft 7A can rotate in the direction of the arrow R2 in fig. 2. As shown in fig. 4,

bearings

29a and 29b for rotatably supporting the support body 32 are provided on the transmission shaft 7A.

The first counter gear 1A, the second counter gear 1B, the support body 32, and the output gear 31 are disposed inside the housing 8 (see fig. 1). The housing 8 is fixed to the support body 32 and is rotatable together with the support body 32 about the first axis Ax1 (i.e., about the transmission shaft 7A).

The joint mechanism Mj is not limited to the example of the joint unit 100. For example, the support body 32 need not be disposed between the first counter gear 1A and the second counter gear 1B. For example, the support body 32 may be formed in a housing shape surrounding the first counter gear 1A, the second counter gear 1B, and the output gear 31.

As shown in fig. 2 and 4, the coupling portion 11 of the first operating arm 10 includes a first portion 11a and a second portion 11b that face each other in the direction of the second axis Ax 2. A support 32 and an output gear 31 are disposed between the first portion 11a and the second portion 11 b. As shown in fig. 4, the first portion 11a is fixed to the output gear 31 by a fixing member 33 such as a screw. Thus, the first operating arm 10 operates about the first axis Ax1 in accordance with the rotation of the output gear 31 about the first axis Ax 1. Similarly, the first operating arm 10 operates about the second axis Ax2 in accordance with the rotation of the output gear 31 about the second axis Ax 2.

As shown in fig. 4, the joint mechanism Mj may also have an elastic body 34 (e.g., rubber or spring) that urges the first portion 11a toward the first axis Ax 1. Thereby, the output gear 31 is pressed by the first counter gear 1A and the second counter gear 1B, and the backlash of the gears can be reduced. In the example of the joint unit 100, the elastic body 34 is disposed between the support body 32 and the second portion 11b, and presses the second portion 11b in a direction away from the support body 32. Thereby, the first portion 11a is urged toward the first axis Ax 1.

As shown in fig. 2, a part of the first counter gear 1A in the circumferential direction around the first axis Ax1 is cut in conjunction with a detectable range of an angle sensor 9A described later. The joint mechanism Mj has a fixing member 13 attached to the cut portion to fix the first counter gear 1A to the transmission shaft 7A. The shape of the first counter gear 1A is not limited to the example of the joint unit 100. The first counter gear 1A may be formed over the entire circumference.

As shown in fig. 3, the joint unit 100 includes: a first drive mechanism M1 having a first electric motor 3A and outputting a rotational force (torque) for rotating the first counter gear 1A; the second driving mechanism M2 has a second electric motor 3B and outputs a rotational force (torque) for rotating the second counter gear 1B.

In the example of the joint unit 100, the first drive mechanism M1 has a first transmission gear 5A. The first transmission gear 5A engages with a gear formed on an output shaft 3A (see fig. 2) of the first electric motor 3A, and receives a rotational force from the first electric motor 3A to rotate. The first transmission gear 5A is coupled to the first counter gear 1A via a transmission shaft 7A, and the first transmission gear 5A rotates integrally with the first counter gear 1A. The second drive mechanism M2 has a second transmission gear 5B. The second transmission gear 5B engages with a gear formed on an output shaft 3B (see fig. 2) of the second electric motor 3B, and receives a rotational force from the second electric motor 3B to rotate. The second transmission gear 5B is coupled to the second counter gear 1B, and the second transmission gear 5B rotates integrally with the second counter gear 1B.

In the example of the joint unit 100, the diameter (number of teeth) of each of the transmission gears 5A, B is larger than the diameter (number of teeth) of the gears provided on the

output shafts

3A, 3B of the

electric motors

3A, 3B. Thereby, the rotations of the

output shafts

3A, 3B of the

electric motors

3A, 3B are decelerated and input to the transmission gears 5A, 5B. The first electric motor 3A and the second electric motor 3B can rotate the

output shafts

3A and 3B in the clockwise direction and the counterclockwise direction. Thereby, the first counter gear 1A and the second counter gear 1B can be rotated in the same direction or in opposite directions to each other. The first electric motor 3A and the second electric motor 3B are preferably reduction motors having a speed reducer built therein, but are not necessarily limited thereto.

As shown in fig. 3, both the first drive mechanism M1 and the second drive mechanism M2 are positioned in the same direction with respect to the joint mechanism Mj. That is, when the drive mechanisms M1 and M2 observe the joint mechanism Mj in one direction, they are located in the same direction as the joint mechanism Mj. In the example of the joint unit 100, both the first drive mechanism M1 and the second drive mechanism M2 are located in the direction along the first axis Ax1 with respect to the joint mechanism Mj. That is, when the joint mechanism Mj is viewed in the direction perpendicular to the first axis Ax1, the drive mechanisms M1, M2 are located in the direction along the first axis Ax 1. In other words, the first drive mechanism M1 and the second drive mechanism M2 are located on the opposite side of the first counter gear 1A with the second counter gear 1B therebetween. When the joint mechanism Mj is viewed in a direction perpendicular to the first axis Ax1, the drive mechanisms M1 and M2 are located on the opposite side of the first counter gear 1A with the second counter gear 1B interposed therebetween.

With this arrangement of the drive mechanisms M1, M2, the two drive mechanisms M1, M2 are located close to each other, in other words, the two

electric motors

3A, 3B are located close to each other, and therefore the joint unit 100 can be easily mounted on a device such as a robot. For example, it is easy to provide two drive mechanisms M1, M2 in the trunk of the robot. Further, a space in which no component is disposed is formed on the side opposite to the drive mechanisms M1 and M2 with the joint mechanism Mj interposed therebetween. Therefore, the first working arm 10 can be moved greatly into the space. That is, the movable range of the first operating arm 10 can be expanded in the direction of the arrow R3 shown in fig. 3. For example, in a configuration in which the second drive mechanism M2 is located on the opposite side of the first drive mechanism M1 with the joint mechanism Mj interposed therebetween, the movable range of the first operating arm 10 in the direction of the arrow R3 is limited by the second drive mechanism M2.

The drive mechanisms M1, M2 are located in the direction along the first axis Ax1 with respect to the joint mechanism Mj. Therefore, when the drive mechanisms M1 and M2 are provided in the trunk of the robot simulating a human or animal and the first axis Ax1 is arranged in the left-right direction of the trunk, the motion of the first working arm 10 about the first axis Ax1 is the motion in the front-back direction of the robot. The movement of the first working arm 10 about the second axis Ax2 is the movement of the robot in the left-right direction. Thereby, the first working arm 10 can perform the movement of the limbs of the human or animal. For example, it is possible to raise the first working arm 10 forward, and thereafter, move the first working arm 10 rightward or leftward.

The first transmission gear 5A and the second transmission gear 5B are disposed on a common axis. In the example of the joint unit 100, as described above, the first transmission gear 5A and the second transmission gear 5B are disposed on the first axis Ax and are rotatable about the first axis Ax. This can reduce the space required for disposing the two

gears

5A and 5B, for example, compared to a configuration in which the two

gears

5A and 5B are disposed on two different axes.

In addition to the transmission gears 5A, 5B, the first counter gear 1A and the second counter gear 1B are also arranged on the first axis Ax. Therefore, in the example of the joint unit 100, all of the first counter gear 1A, the second counter gear 1B, the first transmission gear 5A, and the second transmission gear 5B are disposed on the first axis Ax1 and are rotatable about the first axis Ax. Thus, the space required for the structure for transmitting rotation from the first transmission gear 5A to the first counter gear 1A and the structure for transmitting rotation from the second transmission gear 5B to the second counter gear 5A can be reduced. In the example of the joint unit 100, rotation is transmitted from the first transmission gear 5A to the first counter gear 1A by the transmission shaft 7A disposed on the first axis Ax 1. On the other hand, the second transmission gear 5B and the second counter gear 5A are disposed adjacent to each other and directly connected.

As shown in fig. 4, the joint unit 100 includes a transmission shaft 7A that connects the first drive mechanism M1 and the first counter gear 1A and can transmit the rotational force of the first drive mechanism M1 to the first counter gear 1A. In the example of the joint unit 100, the transmission shaft 7A is disposed on the first axis Ax1, and couples the first transmission gear 5A and the first counter gear 1A. The first transmission gear 5A, the first counter gear 1A, and the transmission shaft 7A are fixed to each other so as to rotate integrally about the first axis Ax 1.

As described above, the first driving mechanism M1 (specifically, the first transmission gear 5A) is disposed on the opposite side of the first counter gear 1A with the second counter gear 1B therebetween. Therefore, the transmission shaft 7A penetrates the second counter gear 1B in the direction of the first axis Ax 1. The second counter gear 1B is independent from the transmission shaft 7A and is rotatable. For example, the second counter gear 1B and the transmission shaft 7A can be rotated in mutually opposite directions, or in the same direction. In the example of the joint unit 100, as shown in fig. 4, a bearing 21 is disposed inside the second counter gear 1B. The second counter gear 1B is rotatably supported by the transmission shaft 7A via a bearing 21.

As shown in fig. 4, in the example of the joint unit 100, the second counter gear 1B and the second transmission gear 5B are disposed between the first counter gear 1A and the first transmission gear 5A. That is, in the example of the joint unit 100, the first counter gear 1A, the second counter gear 1B, the second transmission gear 5B, and the first transmission gear 5A are arranged in the direction of the first axis a1 in the order described herein. Therefore, the transmission shaft 7A penetrates the second counter gear 1B and the second transmission gear 5B. The second transmission gear 5B is independent from the transmission shaft 7A and is rotatable. For example, the second transmission gear 5B and the transmission shaft 7A can rotate in mutually opposite directions, or in the same direction. In the example of the joint unit 100, the bearings 22 and 23 are disposed inside the second transmission gear 5B. The second transmission gear 5B is rotatably supported by the transmission shaft 7A via bearings 22 and 23.

As shown in fig. 4, in the example of the joint unit 100, the first transmission gear 5A, the second transmission gear 5B, and the

output shafts

3A and 3B of the

electric motors

3A and 3B are housed in the housing 7. The housing 7 opens facing the joint mechanism Mj. A bearing 24 is mounted at the edge of the opening. The second transmission gear 5B has a portion located inside the bearing 24, and is rotatably supported by the bearing 24.

As shown in fig. 4, in the example of the joint unit 100, the second transmission gear 5B is rotatably supported inside the bearing 24, and the bearings 22 and 23 are disposed inside the second transmission gear 5B. A transmission shaft 7A is disposed inside the bearings 22 and 23. Therefore, the center portion of the transmission shaft 7A in the direction of the first axis Ax1 is supported by the bearing 24 through the second transmission gear 5B and the bearings 22 and 23. A bearing 25 is also attached to an end of the transmission shaft 7A. The bearing 25 is fixed to the housing 7. That is, the transmission shaft 7A is supported by the central portion and the end portions thereof. That is, the transmission shaft 7A is supported by the central portion and one end portion thereof, and a member (bearing) for rotatably supporting the transmission shaft 7A is not provided at the other end portion. The support position of the transmission shaft 7A can be changed as appropriate.

The second transmission gear 5B and the second counter gear 1B are disposed between the first counter gear 1A and the first transmission gear 5A. Also, the second transmission gear 5B and the second counter gear 1B are fixed to each other so that they rotate integrally. As shown in fig. 4, in the example of the joint unit 100, the second transmission gear 5B and the second counter gear 1B are disposed on the first axis Ax1 and connected to each other. This can reduce the width of the joint unit 100 in the direction of the first axis Ax 1. As shown in fig. 3, in the example of the joint unit 100, the second transmission gear 5B and the second counter gear 1B are fixed to each other by a fixing member 26 such as a screw. The fixing structure of the second transmission gear 5B and the second counter gear 1B is not limited to the example of the joint unit 100. For example, instead of using a fixing member, the second transmission gear 5B and the second counter gear 1B may be pulled to each other so as to rotate integrally. In other examples, the second transmission gear 5B and the second counter gear 1B may not be directly connected to each other. That is, another member may be disposed between the second transmission gear 5B and the second counter gear 1B, and the rotation of the second transmission gear 5B may be transmitted to the second counter gear 1B by this member.

As shown in fig. 5, the first electric motor 3A is located at a position separated from the first axis Ax1 in the radial direction of the first transmission gear 5A. The output shaft 3A (see fig. 2) of the first electric motor 3A and the first transmission gear 5A are coupled to each other so as to rotate integrally therewith. In the example of the joint unit 100, as described above, the gear formed on the output shaft 3A of the first electric motor 3A directly engages with the first transmission gear 5A (see fig. 2). Similarly, the second electric motor 3B is located at a position separated from the first axis Ax1 in the radial direction of the second transmission gear 5B. An output shaft 3B (see fig. 2) of the second electric motor 3B is connected to the second transmission gear 5B and rotates integrally therewith. In the example of the joint unit 100, the gear formed on the output shaft 3B of the second electric motor 3B directly engages with the second transmission gear 5B (see fig. 2). The transmission gears 5A and 5B do not have to be directly engaged with the gears of the

output shafts

3A and 3B of the

electric motors

3A and 3B. For example, another gear may be disposed therebetween. Instead of the transmission gears 5A and 5B, pulleys may be provided on the first axis Ax, and the

output shafts

3A and 3B of the

electric motors

3A and 3B may be coupled to the pulleys by belts. The first electric motor 3A and the second electric motor 3B are arranged with their

output shafts

3A, 3B parallel. That is, the

output shafts

3A and 3B of the two

electric motors

3A and 3B have the same axial direction.

As described above, the first counter gear 1A and the second counter gear 1B are rotatable about the first axis Ax 1. The

electric motors

3A and 3B have their

output shafts

3A and 3B arranged in parallel with the first axis Ax 1. That is, the

output shafts

3A, 3B of the

electric motors

3A, 3B are rotatable about an axis parallel to the first axis Ax 1.

As shown in fig. 5, the first electric motor 3A and the second electric motor 3B are disposed in proximity to each other. More specifically, no other component is disposed between the first electric motor 3A and the second electric motor 3B. In the example of the joint unit 100, the angle between the first electric motor 3A and the second electric motor 3B is smaller than 90 degrees in the circumferential direction around the first axis Ax 1. Therefore, assuming a vertical plane Pv passing through the first axis Ax1 and a horizontal plane Ph passing through the first axis Ax1, the first electric motor 3A and the second electric motor 3B are located in a common quadrant (the second quadrant in the example of fig. 5). In the example of the joint unit 100, the

electric motors

3A and 3B do not intersect the vertical plane Pv.

With the above-described design of the

electric motors

3A and 3B, the plurality of joint units 100 can be easily mounted on a device such as a robot. Fig. 6 is a diagram showing a design in a case where two joint units 100 are mounted on an apparatus such as a robot. In the example of the figure, two joint units 100 are symmetrically arranged. As described above, the

electric motors

3A and 3B are arranged in a common quadrant and do not intersect the vertical plane Pv. Therefore, as shown in the example of fig. 6, the

electric motors

3A and 3B of one joint unit 100 and the

electric motors

3A and 3B of the other joint unit 100 can be arranged so as to overlap each other in a front view.

As shown in fig. 4, the joint unit 100 includes: an angle sensor 9A that detects the displacement of the first operating arm 10 about the first axis Ax 1; and an angle sensor 9B for detecting the displacement of the first operating arm 10 centered on the second axis Ax 2. The

angle sensors

9A and 9B are, for example, potentiometers. The

angle sensors

9A and 9B may be other angle/rotation sensors such as rotary encoders.

In the example of the joint unit 100, the angle sensor 9A is disposed on a transmission path of the rotational force from the first electric motor 3A to the first counter gear 1A in order to detect the rotation of a member closer to the first counter gear 1A than the first electric motor 3A. In the example of the joint unit 100, the movable portion (input portion) of the angle sensor 9A is attached to the transmission shaft 7A, and outputs a signal corresponding to the rotation of the transmission shaft 7A. According to this configuration, for example, the difference between the displacement of the first operating arm 10 and the output of the angle sensor 9A can be reduced as compared with the case where the angle sensor 9A is attached to the output shaft 3A of the electric motor 3A. In the example of the joint unit 100, the movable portion (input portion) of the angle sensor 9 is attached to the end portion of the transmission shaft 7A, and the fixed portion of the angle sensor 9A is fixed to the housing 7.

The angle sensor 9B detects rotation of a member disposed closer to the second counter gear 1B than the second electric motor 3B on a transmission path of the rotational force from the second electric motor 3B to the second counter gear 1B. In the example of the joint unit 100, the angle sensor 9B is attached to the second transmission gear 5B and outputs a signal corresponding to the rotation of the second transmission gear 5B.

The angle sensor 9B is disposed on the transmission shaft 7A and between the first transmission gear 5A and the second transmission gear 5B. A transmission member 28 that engages with the second transmission gear 5B and rotates integrally with the second transmission gear 5B is disposed inside the angle sensor 9B. The movable portion (input portion) of the angle sensor 9B is attached to the transmission member 28, and the rotation of the second transmission gear 5B is transmitted to the angle sensor 9B through the transmission member 28. The transmission member 28 is disposed on the transmission shaft 7A, and is rotatable independently of the transmission shaft 7A. The fixing portion of the angle sensor 9B is fixed to the housing 7.

The joint unit 100 may have a structure that defines the movable range of the first operating arm 10. For example, the joint unit 100 may also have a stopper that limits the movable range of the first operating arm 10 centered on the first axis Ax 1. Fig. 7 is an enlarged view of fig. 1. As shown in fig. 7, a stopper 7a is formed at the edge of the opening of the housing 7. As described above, the joint unit 100 includes the housing 8 that houses the joint mechanism Mj and is rotatable about the first axis Ax1 together with the output gear 31 and the support body 32. The housing 8 has a stopper 8a at a position corresponding to the stopper 7 a. When the first operating arm 10 rotates to a predetermined angle around the first axis Ax1, the stopper 8a contacts the stopper 7a, thereby restricting the movable range of the first operating arm 10.

The joint unit 100 may also include a stopper that limits the movable range of the first operating arm 10 about the second axis Ax 2. The first working arm 10 has a joint 11. As described above, the connecting portion 11 is connected to the output gear 31 and rotates together with the output gear 31. As shown in fig. 4, the support member 32 is disposed between the first portion 11a and the second portion 11b of the coupling portion 11. One stopper may be formed on the support member 32, and the other stopper may be formed on the inner surface of the coupling portion 11 (for example, the inner surface of the second portion 11 b). Further, when the first operating arm 10 rotates to a predetermined angle around the second axis Ax2, the stopper of the coupling portion 11 may contact the stopper of the support member 32. This can restrict the movable range of the first operating arm 10 around the second axis Ax 2.

As described above, in the joint unit 100, the joint mechanism Mj combines the rotation of the first counter gear 1A and the rotation of the second gear 1B to realize the operation of the first operating arm 10 about the first axis Ax1 and the operation of the first operating arm 10 about the second axis Ax 2. Specifically, the difference between the rotation of the first counter gear 1A and the rotation of the second counter gear 1B is converted into the movement of the first operating arm 10 about the second axis Ax 2. With this joint mechanism Mj, the rotational force of the first electric motor 3A and the rotational force of the second electric motor 3B can be used in each of the operation of the first operating arm 10 about the first axis Ax1 and the operation of the first operating arm 10 about the second axis Ax2, and therefore the operating force of the first operating arm 10 can be increased. Both the first drive mechanism M1 and the second drive mechanism M2 are positioned in the same direction with respect to the joint mechanism Mj. Therefore, according to the arrangement of the drive mechanisms M1 and M2, the positions of the two drive mechanisms M1 and M2 are close to each other, and therefore the joint unit 100 can be easily mounted on a device such as a robot.

The present invention is not limited to the above-described example of the joint unit 100, and various modifications can be made.

For example, the reduction gear ratio of the driving mechanism M1 (e.g., the reduction gear ratio achieved by the first transmission gear 5A and the first electric motor 3A) may be made different from the reduction gear ratio of the driving mechanism M2 (e.g., the reduction gear ratio achieved by the second transmission gear 5B and the second electric motor 3B).

In another example, the output shaft 3A of the first electric motor 3A may be directly coupled to the transmission shaft 7 a. For example, the first electric motor 3A may be disposed on the first axis Ax1 and directly couple the output shaft 3A and the transmission shaft 7a to each other.

In the example of the joint unit 100, the second transmission gear 5B and the second counter gear 1B are disposed between the first transmission gear 5A and the first counter gear 1A. However, the four gears may be arranged in the order of the second transmission gear 5B, the first transmission gear 5A, the second counter gear 1B, and the first counter gear 1A on the first axis Ax 1.

The joint mechanism Mj is not limited to the configuration shown in fig. 3 and 4, as long as it is a mechanism that combines the rotation of the first counter gear 1A and the rotation of the second counter gear 1B to realize the operation of the first operating arm 10 about the first axis Ax1 and the operation of the first operating arm 10 about the second axis Ax 2.

Claims

1. A joint unit, comprising:

a working arm;

a joint mechanism provided in the working arm, allowing the movement of the working arm about a first axis and the movement of the working arm about a second axis intersecting the first axis, having a first gear and a second gear that are rotatable independently of each other, and combining the rotation of the first gear and the rotation of the second gear to realize the movement of the working arm about the first axis and the movement of the working arm about the second axis;

a first drive mechanism having a first electric motor and outputting a rotational force for rotating the first gear;

a second drive mechanism having a second electric motor and outputting a rotational force for rotating the second gear;

the first drive mechanism and the second drive mechanism are both located in a first direction with respect to the joint mechanism,

the first gear and the second gear are arranged on the first axis,

the first drive mechanism has a first transmission rotation member that is disposed on the first axis and receives a rotational force of the first electric motor,

the second drive mechanism includes a second transmission rotating member that is disposed on the first axis and receives a rotational force of the second electric motor,

the second gear and the second transmission rotation member are disposed between the first gear and the first transmission rotation member,

the first transmission rotating member and the first gear are coupled to each other by a transmission shaft disposed on the first axis,

the central part and one end part of the transmission shaft are supported by a bearing,

a bearing for rotatably supporting the other end of the transmission shaft is not provided.

2. The joint unit of claim 1,

the second gear is directly connected to the second transmission rotating member.

3. The joint unit of claim 1,

the second gear and the second transmission rotating member are disposed inside the first bearing,

a second bearing is disposed inside the second gear and the second transmission rotating member,

the transmission shaft is disposed inside the second bearing.

4. The joint unit of claim 1,

a first angle sensor that detects rotation of a member closer to the first gear than the first electric motor in a transmission path of the rotational force from the first electric motor to the first gear,

the second angle sensor detects rotation of a member closer to the second gear than the second electric motor in a transmission path of the rotational force from the second electric motor to the second gear.

5. The joint unit of claim 1,

the first electric motor and the second electric motor are located on the same side with respect to a vertical plane including the first axis and orthogonal to the second axis, and do not intersect the vertical plane.

6. The joint unit of claim 1,

the joint mechanism includes an output gear that is engaged with the first gear and the second gear and is rotatable about an axis orthogonal to axes of the first gear and the second gear,

the first gear, the second gear, and the output gear are integrally rotatable around axes of the first gear and the second gear,

the working arm is coupled to the output gear.

7. The joint unit of claim 1,

the first gear and the second gear are opposed in the first direction,

the first drive mechanism and the second drive mechanism are located on the opposite side of the first gear with the second gear interposed therebetween.

8. The joint unit of claim 1,

an output shaft of the first electric motor is located at a position separated from the first axis in a radial direction of the first transmitting/rotating member, and is directly or indirectly coupled to the first transmitting/rotating member,

the output shaft of the second electric motor is located at a position separated from the first axis in the radial direction of the second transmission rotating member, and is directly or indirectly coupled to the second transmission rotating member.

9. The joint unit of claim 1,

the first gear and the second gear are rotatable about an axis in the first direction, and the output shaft of the first electric motor and the output shaft of the second electric motor are rotatable about an axis in the first direction.

10. The joint unit of claim 1,

the first electric motor is proximate to the second electric motor.

11. A joint unit, comprising:

a working arm;

12. The joint unit of claim 11,

13. The joint unit of claim 11,

the transmission shaft is disposed inside the second bearing.

14. The joint unit of claim 11,

15. The joint unit of claim 11,

the working arm is coupled to the output gear.

16. The joint unit of claim 11,

the first gear and the second gear are opposed in the first direction,

17. The joint unit of claim 11,

18. The joint unit of claim 11,

19. The joint unit of claim 11,

the first electric motor is proximate to the second electric motor.