JP5527299B2 - Gear unit and robot - Google Patents

Description

  The disclosed embodiments relate to a gear unit and a robot.

  Conventionally, as a joint structure for connecting a movable body such as an arm or a hand of a robot, a rotating shaft that connects the movable body to the tip and a drive shaft that connects the base end to a driving source such as a motor are connected via a gear unit. There are some which are interlockedly connected in an orthogonal state (see, for example, Patent Document 1).

  For example, a gear unit disclosed in Patent Document 1 is fixed to a first bevel gear fixed to the distal end of a drive shaft that forms the opposite side of the motor and a proximal end of a rotary shaft that forms the opposite side of the movable body. The second bevel gear meshes with the first bevel gear.

  However, since the robot disclosed in Patent Document 1 drives only one movable body with one joint, improvement in work efficiency with an arm or hand as a movable body cannot be expected.

  Therefore, a gear unit that can drive a plurality of movable bodies by one joint used in a robot or the like is desired. As such a gear unit, a drive mechanism that individually drives a rotating shaft composed of a plurality of concentric axes. Is known (see, for example, Patent Document 2).

JP 58-165992 A JP 2007-216364 A

  However, since the gear unit disclosed in Patent Document 2 is configured to wind the timing belt around pulleys provided on the respective rotation shafts composed of a plurality of concentric shafts, and drive each rotation shaft via the timing belt. It is difficult to make a compact unit.

  In addition, it is difficult to provide a sufficient interval according to the application between movable bodies (arms and hands) that are connected to the respective rotation shafts and pivot.

  One aspect of the embodiment has been made in view of the above, and can be unitized compactly while improving work efficiency by a movable body (an arm or a hand), and between movable bodies. An object of the present invention is to provide a gear unit capable of providing a sufficient interval according to the use and a robot including the gear unit.

A gear unit according to an aspect of the embodiment includes a coaxial inner shaft and outer shaft configured by two concentric output shafts, and an inner gear and a base end of the outer shaft that are attached in the middle of the inner shaft. A first input shaft having a first input gear extending in a direction orthogonal to the output shaft and meshing with the inner gear ; and a second input gear meshing with the outer gear. A second input shaft. Then, the pair of the inner gear and the first input gear and the pair of the outer gear and the second input gear are respectively configured by hypoid gears, and the inner gear and the outer gear are separated from each other at a predetermined interval. while disposed opposite each other spaced, and said first input shaft and the second input shaft, causes spaced apart by a predetermined distance from each other in the axial direction of the output shaft, in plan view, through the output shaft The first input shaft and the inner shaft are separated from each other, and the second input shaft and the outer shaft are prevented from intersecting each other. Further, the distance between the inner gear and the outer gear can mesh with the inner gear without the first input gear interfering with the outer gear, and the second input gear interferes with the inner gear. it shall be the as much as possible short interval enough to the outer gear and meshing without.

  According to one aspect of the embodiment, it is possible to make a compact unit while improving work efficiency by a movable body (an arm or a hand), and a sufficient interval according to the application is provided between the movable bodies. Can be provided. Therefore, for example, it can be suitably used for a robot joint drive mechanism.

Drawing 1 is an explanatory view by the longitudinal section view of the gear unit concerning a 1st embodiment. FIG. 2 is an explanatory diagram in plan view of the gear unit. FIG. 3 is an explanatory diagram of the gear unit as viewed from the back. FIG. 4 is an explanatory diagram viewed from above the gear unit according to the first modification. FIG. 5A is an explanatory diagram viewed from above the gear unit according to the second embodiment. FIG. 5B is an explanatory diagram viewed from above the gear unit according to the third embodiment. FIG. 5C is an explanatory diagram viewed from above the gear unit according to the fourth embodiment. FIG. 6A is an explanatory diagram illustrating an example of the robot according to the first embodiment. FIG. 6B is a schematic explanatory diagram illustrating an example when the gear unit according to the first embodiment is applied to a robot. FIG. 6C is a schematic explanatory diagram illustrating an example when the gear unit according to the first embodiment is applied to a robot. FIG. 7 is an explanatory view of the gear unit according to the reference example as viewed in a vertical cross section. FIG. 8A is a schematic explanatory diagram illustrating an example when the gear unit according to the first embodiment and the gear unit according to the reference example are applied to a robot. FIG. 8B is a schematic explanatory diagram illustrating an example when the gear unit according to the first embodiment and the gear unit according to the reference example are applied to a robot.

  Hereinafter, embodiments of a gear unit and a robot disclosed in the present application will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the examples in the following embodiments.

(First embodiment)
FIG. 1 is an explanatory view of the gear unit according to the first embodiment in a longitudinal sectional view, FIG. 2 is an explanatory view in the same plane view, and FIG. 3 is an explanatory view in the rear view. First, the gear unit 1 according to the present embodiment will be described.

  As shown in FIGS. 1 to 3, the gear unit 1 includes a concentric biaxial output shaft composed of an inner shaft 2 and an outer shaft 3 having concentric central axes, a first input shaft 4 and a second input shaft. 5 and two input shafts. In FIG. 1, the second input shaft 5 is not shown.

  The inner shaft 2 and the outer shaft 3 constituting the output shaft are configured such that the output directions F1 and F2 are opposite to each other, and the output direction F1 of the inner shaft 2 is one side direction (downward direction in FIG. 1). The output direction F2 of the shaft 3 is the other direction (the upper direction in FIG. 1).

  The first input shaft 4 and the second input shaft 5 each extend in a direction orthogonal to the output shaft, and the first input shaft 4 is interlocked with the first motor 11 (FIG. 2), The second input shaft 5 is linked to the second motor 12 (FIG. 2).

  Each motor 11 (12) and each input shaft 4 (5) are connected in the same direction.

  With this configuration, the power flow f1 from the first motor 11 is transferred from the first input shaft 4 to the inner shaft 2 (see FIG. 1), and the power flow f2 from the second motor 12 is transferred to the second input shaft. 5 to the outer shaft 3 (see FIG. 1) can be transmitted directly using gears. The power flow f1 from the first motor 11 is in the one output direction F1 from the inner shaft 2, and the power flow f2 from the second motor 12 is the other output direction F2 that is 180 degrees different from the outer shaft 3. Is transmitted to.

  The gear unit 1 having such a configuration, together with the first motor 11 and the second motor 12, can function as a drive unit for a driven member such as a robot arm described later.

  As shown in FIG. 1, an inner gear 6 is provided in the middle of the inner shaft 2 that is an output shaft, that is, near one end of the inner shaft 2 (near the lower end in FIG. 1). An outer gear 7 is provided at the base end (lower end in FIG. 1) of the outer shaft 3 that is shorter than the inner shaft 2. On the other hand, as shown in FIG. 2, a first input gear 8 is provided at the tip of the first input shaft 4 that is an input shaft, and a second input gear 9 is provided at the tip of the second input shaft 5. ing.

  The output shaft and the input shaft are attached to the unit case 10 via bearings 15 and a seal material 16 (not shown in FIG. 1) in a posture extending in directions orthogonal to each other.

  That is, a through hole is formed from one side surface of the unit case 10 to the other side surface (from the upper surface to the lower surface in FIG. 1), and the output shaft (the inner shaft 2 and the outer shaft 3) is inserted into the through hole. An opening is formed in another side surface (left side surface in FIG. 1) orthogonal to the input shaft, and the input shaft is inserted through this opening. In addition, the front end side of the outer shaft 3 protrudes from one end opening (the upper opening in FIG. 1) of the through hole, and the inner shaft extends from the other end opening (the lower opening in FIG. 1) of the through hole. One end side of 2 is projected.

  Then, as shown in FIG. 1, the hands 330 and 340 (see FIG. 6A) are connected to the inner shaft 2 and the outer shaft 3, and the gear unit 1 is used as a driving unit for a robot hand, which will be described later. Can be arranged.

  By the way, the inner gear 6 and the outer gear 7 are disposed in an opposing state in the unit case 10. That is, the inner gear 6 provided in the vicinity of one end of the relatively long inner shaft 2 and the outer gear 7 provided at the proximal end of the relatively short outer shaft 3 make the tooth rows face each other. Thus, they are arranged in a facing state with a predetermined distance D from each other.

  The space formed with the predetermined distance D forms a gear meshing space Q. In this embodiment, the gear unit 1 is made compact by making the gear meshing space Q as small as possible. doing.

  That is, in the gear meshing space Q made as small as possible, the first input shaft 4 and the second input shaft 5 are separated from each other by a predetermined distance L in the direction of the concentric axis of the output shaft composed of the inner shaft 2 and the outer shaft 3. Only spaced apart.

  And in the attitude | position which leveled the input shaft, as shown in FIG. 1, the gear unit 1 in this embodiment has the 1st input shaft 4 located in the relatively lower side relatively to the inner shaft 2. The second input shaft 5 located on the upper side is configured to interlock with the outer shaft 3.

  Thus, in the gear meshing space Q formed between the inner gear 6 and the outer gear 7 that are arranged to face each other, the first input gear 8 of the first input shaft 4 and the inner gear 6 mesh, The first input shaft 4 and the second input shaft 5 are offset from each other in the output shaft direction so that the second input gear 9 and the outer gear 7 of the second input shaft 5 are engaged with each other.

  Therefore, the gear unit 1 according to the present embodiment has a compact configuration, and includes a pair of the inner gear 6 and the first input gear 8 that are independent from each other, and the outer gear 7 and the second input gear 9. You will have a pair of pairs.

  That is, the pair of inner gear 6 and first input gear 8 and the pair of outer gear 7 and second input gear 9 do not interfere with each other, and are independent power transmission systems. (See f1 → F1 and f2 → F2 shown in FIG. 1).

  By the way, in the gear unit 1 according to the present embodiment, the pair of the inner gear 6 and the first input gear 8 and the pair of the outer gear 7 and the second input gear 9 are each constituted by a hypoid gear.

  Therefore, the axes of the first input shaft 4 provided with the first input gear 8 and the inner shaft 2 provided with the inner gear 6 meshing with the first input gear 8 do not intersect each other. Further, the axes of the second input shaft 5 including the second input gear 9 and the outer shaft 3 including the outer gear 7 meshing with the second input gear 9 do not intersect with each other.

  Therefore, the respective axes of the first input shaft 4 and the second input shaft 5 can be arbitrarily arranged without matching the axes of the inner shaft 2 and the outer shaft 3, and the first and second motors 11 can be arranged. , 12, the degree of freedom of the layout of the drive unit can be increased.

  For example, as shown in FIG. 2, the first input shaft 4 and the second input shaft 5 can be arranged in parallel to each other.

  As described above, the first input shaft 4 and the second input shaft 5 can be arranged in parallel with each other using the hypoid gear, so that the first motor 11 and the second motor 12 are also arranged in the same direction. Is possible. Therefore, the gear unit 1 can be made more compact in combination with the gear meshing space Q formed with a predetermined interval D (see FIG. 1) made as narrow as possible.

  As described above, the gear unit 1 according to the present embodiment includes the inner shaft 2 and the outer shaft 3 that are concentric and have output directions opposite to each other as a basic configuration. Further, a first input shaft 4 linked to the inner shaft 2 and a second input shaft 5 linked to the outer shaft 3 are provided. As described above, the inner shaft 2 and the outer shaft 3 form a concentric two-axis output shaft, while the first input shaft 4 and the second input shaft 5 extend in directions orthogonal to the output shaft, respectively. ing.

  And the inner gear 6 attached to the inner shaft 2 and the outer gear 7 attached to the outer shaft 3 are arranged in a state of facing each other.

  Further, the first input shaft 4 and the second input shaft 5 are arranged apart from each other by a predetermined distance L in the axial direction of the output shaft, and the first input gear of the first input shaft 4 is disposed on the inner gear 6. 8, while the outer gear 7 meshes with the second input gear 9 of the second input shaft 5.

  With this configuration, the gear unit 1 can be made compact, and the two movable bodies can be driven via the coaxial output shafts (the inner shaft 2 and the outer shaft 3). Therefore, if the movable body is a hand such as a robot, the working efficiency of the robot can be improved.

  Further, the rotational force of the first input shaft 4 serving as the power of the first motor 11 is applied to the inner shaft 2 via the first input gear 8 and the inner gear 6, and the second input shaft serving as the power of the second motor 12. The rotational force 5 is directly and independently transmitted to the outer shaft 3 via the second input gear 9 and the outer gear 7.

  As shown in FIG. 1, the inner shaft 2 and the outer shaft 3 both have hollow shaft bodies 21 and 31, and can be wired and / or piped through the shaft body 21 of the inner shaft 2.

  Therefore, for example, as will be described later, when the gear unit 1 is applied to a robot and an arm or hand is connected to the output shaft, wiring to the sensors or actuators provided on the arm or hand, air piping, etc. The inner shaft 2 can be inserted into the shaft body 21.

(Modification of gear unit 1)
Next, a modification of the gear unit 1 will be described with reference to FIG. The gear unit 1 according to the modification shown in FIG. 4 is configured to include a stopper mechanism 100 so that the rotation angle of the output shaft is mechanically restricted by 180 degrees + α in the forward and reverse directions.

  As shown in FIG. 4, the stopper mechanism 100 provided in the gear unit 1 according to the modification has a stopper pin 61 protruding from the tooth row surface side of the inner gear 6. On the other hand, a belt pin 62 projects from the inner wall of the unit case 10 so as to be positioned on a center line CL passing through the concentric shafts of the inner shaft 2 and the outer shaft 3 that are output shafts. A stopper belt 63 is wound between the belt pin 62 and the inner shaft 2 so as to maintain an appropriate tension. The stopper belt 63 is desirably an elastic belt having an appropriate elasticity.

  With such a configuration, when the inner gear 6 rotates through the first input shaft 4 (first input gear 8) to which the rotational power is transmitted from the first motor 11, as shown by the arrow f in FIG. The stopper pin 61 also rotates as the inner gear 6 rotates.

  When the rotation proceeds to a predetermined angle, the stopper pin 61 comes into contact with the stopper belt 63 and the rotation is restricted while pushing the stopper belt 63 by a predetermined amount as shown in the figure. Therefore, the inner shaft 2 interlocked with the rotation of the inner gear 6 provided with the stopper pin 61 protruding is also restricted from rotating further.

  In the example, the rotation angle of the inner shaft 2 is regulated, but a similar configuration can be applied to the outer shaft 3 or can be applied to both the inner shaft 2 and the outer shaft 3 at the same time. .

  Next, second to fourth embodiments of the gear unit will be described with reference to FIGS. 5A to 5C. The gear unit 1 according to the second embodiment shown in FIG. 5A has an intermediate gear mechanism 200 interposed between the first and second motors 11 and 12 and the first and second input shafts 4 and 5. It is said.

  This can be dealt with when the arrangement positions of the first motor 11 and the second motor 12 are limited for some reason, or when the size of the first motor 11 and the second motor 12 is too large. That is, when the first and second input shafts 4 and 5 are directly connected to the motor shafts 110 and 120, it is possible to cope with the case where the first input gear 8 and the second input gear 9 cannot mesh with the inner gear 6 and the outer gear 7. It is what.

  The example shown in FIG. 5A is a case where, for example, the layout of the motor connector 210 is limited, and an interval must be provided between the first motor 11 and the second motor 12. That is, if the distance D1 between the motor shafts 110 and 120 is too large and the first input shaft 4 and the second input shaft 5 are connected to the motor shafts 110 and 120, the first input gear 8 and the second input This is a case where it is difficult for the gear 9 to mesh with the inner gear 6 and the outer gear 7.

  Therefore, as shown in the drawing, the first spur gear (spur gear) 220 is attached to the tip of the motor shaft 110 of the first motor 11, and the second spur gear (spur gear) 230 is attached to the base end of the first input shaft 4. Are engaged. As described above, when the intermediate gear mechanism 200 including the first spur gear 220 and the second spur gear 230 is used, the types of motors that can be used are not limited, and versatility as the gear unit 1 is enhanced. .

  Next, the third and fourth embodiments will be described with reference to FIGS. 5B and 5C. In the gear unit 1 according to the third and fourth embodiments, the inner gear 6 and the first input gear 8, and the outer gear 7 and the second input gear 9 are bevel gears (bevel gears), respectively.

  That is, if a bevel gear is used, unlike the hypoid gear, the axes of the first input shaft 4 and the inner shaft 2 and the axes of the second input shaft 5 and the outer shaft 3 intersect with each other, and the intersecting angles are freely set. Can be set.

  That is, in the first input gear 8 and the inner gear 6 that mesh with each other, the axes of the first input shaft 4 having the first input gear 8 and the inner shaft 2 having the inner gear 6 are connected to each other at a predetermined angle. Can be crossed. Further, in the second input gear 9 and the outer gear 7 that mesh with each other, the axes of the second input shaft 5 having the second input gear 9 and the outer shaft 3 having the outer gear 7 are connected at a predetermined angle. Can be crossed.

  Therefore, as shown in FIG. 5B, the angle θ between the first input shaft 4 and the second input shaft 5 can be set as appropriate. Further, as shown in FIG. 5C, the angle θ is 180 degrees, the first input shaft 4 and the second input shaft 5 are arranged on a straight line, and the first input gear 8 and the second input gear 9 are As with the inner gear 6 and the outer gear 7, they can be arranged in an opposed state.

  Further, similarly to the case using the hypoid gear, the length (height) of the gear unit 1 in the output shaft direction can also be shortened (lower) in the present modified example, so that the gear unit 1 can be made compact. .

  The gear unit 1 described above can be applied to a robot 300 including arms 310 and 320 and hands 330 and 340 as shown in FIGS. 6A and 6B. FIG. 6A is an explanatory view showing an example of the robot according to the first embodiment, and FIG. 6B is a schematic explanatory view showing an application example of the gear unit 1 to the robot. For the robot 300 shown in FIG. 6B, the support 360 that supports the base end of the first arm 310 is not shown.

  As shown in the figure, the robot 300 is a horizontal articulated type, and a support 360 is projected from a base 350, and the base end of the first arm 310 is rotatably connected to the upper end of the support 360. Yes.

  The base end of the second arm 320 is pivotally connected to the tip of the first arm 310, and the first hand 330 is placed on the lower side of the tip of the second arm 320 and the first hand 330 is placed on the upper side. Two hands 340 are attached so as to be independently rotatable. The first hand 330 and the second hand 340 are configured to place or hold a predetermined workpiece.

  In the present embodiment, the above-described gear unit 1 is provided at the distal end portion of the second arm 320 so that the two hands 330 and 340 can be driven independently.

  That is, the first motor 11 and the second motor 12 are interlocked and connected to the first input shaft 4 and the second input shaft 5 of the gear unit 1, while the first hand 330 is connected to the inner shaft 2 and the outer shaft 3. The second hand 340 is connected to the first hand.

  With this configuration, when the first motor 11 rotates, the torque is transmitted to the inner shaft 2 via the first input gear 8 and the inner gear 6 of the first input shaft 4 and is connected to the inner shaft 2. The hand 330 is rotated in the horizontal direction.

  Similarly, when the second motor 12 rotates, the torque is transmitted to the outer shaft 3 via the second input gear 9 and the outer gear 7 of the second input shaft 5, and the second motor 12 is connected to the outer shaft 3. The hand 340 is rotationally driven in the horizontal direction.

  As described above, the first hand 330 and the second hand 340 of the robot 300 operate independently of each other around the concentric rotation axis.

  In the robot 300 including the gear unit 1 described above, an interval corresponding to at least the thickness of the second arm 320 is formed between the first hand 330 and the second hand 340. . Therefore, for example, when two types of gripping objects that are separated by a predetermined distance in the vertical direction are to be gripped by using two hands, the first and second hands 330 and 340 are placed above the second arm 320. It becomes possible to make it a compact configuration in which the height is suppressed as compared with a configuration in which the top and bottom are arranged one above the other.

  As shown in FIG. 6A, the robot 300 is electrically connected to a control unit 370 including a computer having a CPU and a memory storing a robot operation control program. The driving of the first and second motors 11 and 12 is controlled by the control unit 370 according to the work content, and the first hand 330 and the second hand 340 that rotate independently of each other operate. A predetermined operation is performed according to the control program.

  By the way, the gear unit 1 is attached from the outside to the second arm 320 having an open end, for example, by making the outer shape, size, etc. of the unit case 10 correspond to the second arm 320. The arm 320 and the gear unit 1 can be integrated.

  Of course, the gear unit 1 can be housed together with the unit case 10 inside the tip portion of the second arm 320.

  Next, another application example of the gear unit 1 to the robot 300 will be described with reference to FIG. 6C.

  The robot 300 shown in FIG. 6C is provided with the gear unit 1 at the distal end portion of the first arm 310 and connects the second arm 320 to the outer shaft 3 so as to extend horizontally from the upper side of the first arm 310. It is left. A third arm 380 is connected to the tip of the second arm 320 via a rotation shaft 600. A hand may be connected in place of the third arm 380.

  On the other hand, a predetermined hand 390 is connected to the inner shaft 2 of the gear unit 1 and extends in the horizontal direction from the lower side of the first arm 310. That is, the robot 300 in this example has a configuration in which one arm and one hand extend from the upper and lower sides of the first arm 310, respectively.

  In each of the embodiments described above, the inner gear 6 and the outer gear 7 have substantially the same diameter. However, the inner gear 6 and the outer gear 7 do not necessarily have the same diameter. May be different. That is, the first input gear 8 and the second input gear 9 correspond to these, the power of the first motor 11 is directly and independently of the power of the second motor 12 and the outer shaft 3, respectively. It only has to be transmitted.

(Reference example of gear unit)
Next, a gear unit 500 as a reference example will be described with reference to FIG. Here, it demonstrates centering on a different part with respect to the gear unit 1 mentioned above. Therefore, in the following, the same members as those of the gear unit 1 or members having similar functions are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  In the gear unit 500 according to the reference example, the gear unit 1 according to the first embodiment can extract the output from both ends (upper and lower sides in FIG. 1) of the output shaft. The output can be taken out only from one side (the upper side in FIG. 7).

  That is, as shown in FIG. 7, the output from the inner shaft 2 and the outer shaft 3 can be taken out only from one side (upper side in FIG. 7).

  An example in which the gear unit 500 having such a structure is applied to a robot together with the gear unit 1 according to the previous embodiment will be described with reference to FIGS. 8A and 8B. In the following description, the same members as those of the robot 300 according to the first embodiment or members having similar functions are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  In the robot 400 shown in FIG. 8A, the gear unit 1 is provided at the distal end portion of the first arm 310, and the second arm 320 is connected to the outer shaft 3 to extend from the upper side of the first arm 310. The gear unit 500 according to the reference example is provided at the tip of the second arm 320, and the first and second hands 330 and 340 are connected to extend from the upper side of the second arm 320. .

  On the other hand, a predetermined hand 390 is connected to the inner shaft 2 of the gear unit 1 and extends from the lower side of the first arm 310.

  8B, the gear unit 1 is provided at the tip of the first arm 310, the second arm 320 is connected to the outer shaft 3, and the third arm 321 is connected to the inner shaft 2. ing. That is, the second arm 320 is extended from the upper side of the first arm 310, the third arm 321 is extended from the lower side of the first arm 310, and the arms are respectively extended from the upper and lower sides of the first arm 310. The configuration is extended.

  The gear unit 500 according to the reference example is provided at the tip of the second arm 320 extending from the upper side of the first arm 310 to connect the first and second hands 330 and 340. A predetermined hand 390 is connected to the tip of the third arm 321 extending from the lower side of the first arm 310 via a rotation shaft 600.

  As described above, the gear unit 1 can be suitably used for an arm such as the robot 300 or 400 or a joint of a hand. Moreover, since the configuration is compact, it can be built in the tip of the arm or externally attached. Moreover, since the power from the output shaft can be taken out from both ends of the shaft, the structure of the arm or hand is compact, for example, between the first and second hands 330 and 340 according to the application. A sufficient interval can be provided.

  The application example of the gear unit 1 described above is not limited to a robot, and is not necessarily limited to the robots 300 and 400 as described above.

  Further effects and modifications of the above-described embodiment can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

1,500 gear unit 2 inner shaft 3 outer shaft 4 first input shaft 5 second input shaft 11 first motor 12 second motor 6 inner gear 7 outer gear 8 first input gear 9 second input gear 10 unit case L Predetermined distance 300,400 Robot 310 First arm 320 Second arm 330 First hand 340 Second hand

Claims (5)

And the inner shaft and outer shaft coaxial constituted by an output shaft concentric biaxial,
An inner gear attached in the middle of the inner shaft and an outer gear attached to the base end of the outer shaft;
A first input shaft that includes a first input gear that extends in a direction orthogonal to the output shaft and meshes with the inner gear and a second input shaft that meshes with the outer gear ;
With
A pair of the inner gear and the first input gear and a pair of the outer gear and the second input gear are each configured by a hypoid gear,
The inner gear and the outer gear are arranged to face each other at a predetermined interval, while the first input shaft and the second input shaft are arranged at a predetermined distance in the axial direction of the output shaft. And spaced apart with a line passing through the output shaft in plan view,
The axial lines of the first input shaft and the inner shaft and the axial lines of the second input shaft and the outer shaft do not cross each other,
Further, the distance between the inner gear and the outer gear can mesh with the inner gear without the first input gear interfering with the outer gear, and the second input gear interferes with the inner gear. The gear unit is characterized in that it is as short as possible so that it can mesh with the outer gear without any problem. 2. The gear unit according to claim 1, wherein each of the inner shaft and the outer shaft has a hollow shaft body, and wiring and / or piping are possible through the shaft body of the inner shaft. The base,
An arm extending from the base;
The gear unit according to claim 1 or 2 provided at a tip of the arm;
With
A robot having a predetermined arm and / or a predetermined hand selectively connected to the inner shaft and the outer shaft. The base,
A first arm extending from the base;
The gear unit according to claim 1 or 2 , provided at a tip of the first arm;
With
A robot, wherein a second arm is connected to each of an inner shaft and an outer shaft of the gear unit. The base,
A first arm extending from the base;
The gear unit according to claim 1 or 2 , provided at a tip of the first arm;
With
A robot, wherein a second arm is connected to one of an inner shaft and an outer shaft of the gear unit, and a hand is connected to the other.

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