JP2015161382A - Gear mechanism, speed change gear and multi-joint robot arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear mechanism, a speed change gear and a multi-joint robot arm capable of restricting backlash and the like without producing any reduction of torsional stiffness.SOLUTION: This invention comprises a first gear 40 fixed to a casing 11; a second gear 50 rotatably and relatively fixed in an axial direction in respect to the casing 11; a rotatable input shaft 20 coaxially arranged with the first gear 40; an inclined shaft 21 arranged to be inclined in respect to the input shaft 20; an oscillating gear 60 arranged between the first gear 40 and the second gear 50, rotatably arranged in respect to the inclined shaft 21 and engaged with the first gear 40 and the second gear 50 at a specified inclination angle; an output shaft 30 integrally rotated with the second gear 50; and a first biasing gear 70 coaxially arranged with the first gear 40, engaged with the oscillation gear 60, and at the same time fixed in a rotating direction in respect to the first gear 40 and for biasing the oscillation gear 60 in an axial direction.

Description

  The present invention relates to a gear mechanism using a rocking gear mechanism, a transmission using the gear mechanism, and a multi-joint robot arm using the transmission as a joint.

  For joint driving of industrial robots and the like, it is common to apply the output of a high-speed, low-torque electric motor to low-speed, large torque using a speed reducer. Various types of reduction gears have been put into practical use, and one type is a rocking gear mechanism that can obtain a large reduction ratio by the rocking motion of the rocking gear. The oscillating gear mechanism meshes an oscillating gear having a different number of teeth with a fixed gear provided coaxially with the input shaft, and causes the oscillating motion by rotation of the input shaft. Then, an output gear provided coaxially with the input shaft is meshed with a swing gear, and the speed is reduced by the differential of these two sets of gears (see Patent Document 1).

  Further, a reduction gear having a mechanism similar to the swing gear mechanism has been developed (see Patent Document 2). In this speed reducer, an intermediate gear that rotates about an input shaft and an inclined axis is provided between an input gear connected to the input shaft and an output gear arranged coaxially therewith, and the number of teeth of the intermediate gear meshes with it. It is different from the input gear. Thereby, in this reduction device, the rotation of the output gear meshing with the intermediate gear is extracted to the output shaft and decelerated.

  By the way, in this type of device, there is a problem of backlash of the meshing portion between the gears caused by a dimensional error or an assembly error of the gears, and a transmission accuracy of the rotation angle between the input and output shafts due to wear of the tooth surfaces due to long-time driving. There was a problem of decline. Hereinafter, both issues are collectively referred to as backlash. In order to solve these backlashes and the like, Patent Document 1 adopts a rocking gear that can be elastically deformed, or elastically supports the rocking gear so that the rocking gear has a predetermined strength. The fixed gear and the output gear are pressed and meshed with each other. And, by applying a preload to the meshing portion by the elastic deformation on the side of the oscillating gear that occurs along with this, backlash and the like are suppressed. In Patent Document 2, a spring member that elastically biases the input gear and the output gear toward the intermediate gear is employed. A similar effect is obtained by applying a preload to the meshing portion by the spring member.

JP 2010-255777 A JP 2010-52510 A

  However, since the swing gear mechanism of Patent Document 1 described above employs an elastic structure for the meshing portion in order to solve backlash and the like, the torsional rigidity may decrease due to elastic deformation of the meshing portion. Here, the torsional rigidity is represented by the reciprocal of the torsional rotation angle of the output shaft when rotational torque is applied to the output shaft while the input shaft is supported so as not to rotate. In actual use, when the motor operation connected to the input shaft is stopped, the output shaft rotation is twisted and the output shaft rotation stoppage accuracy is reduced. Such a decrease in torsional rigidity causes troubles in assembly with precise positional accuracy in the case of industrial robot arms.

  In the swing gear mechanism of Patent Document 2 described above, the input gear is supported so as to be movable in the axial direction, and is biased in the axial direction by a spring member with respect to the swing gear. For this reason, when a load in the torsional direction is applied to the meshing portion, the input gear may move away from the swinging gear against the spring member, and not only torsional rigidity but also rotation There is a possibility that the transmission accuracy of the angle is also lowered.

  Therefore, an object of the present invention is to provide a gear mechanism, a transmission, and an articulated robot arm that can suppress backlash and the like without causing a decrease in torsional rigidity.

  The gear mechanism of the present invention is arranged with a first gear fixed to a casing, and coaxially and axially opposed to the first gear, and is rotatable with respect to the casing and relative to the axial direction. A second gear fixed to the first gear, a rotatable first shaft provided coaxially with the first gear and the second gear, and a slanted shaft with respect to the first shaft. The tilt shaft is disposed between the first gear and the second gear, and is provided so as to be rotatable with respect to the tilt shaft, and is constant with respect to the first gear and the second gear. A swing gear meshing with an inclination angle is provided coaxially with the first shaft, a second shaft rotating integrally with the second gear, and provided coaxially with the first gear. Meshed with the moving gear and fixed in the rotational direction with respect to the first gear, A first biasing gear for biasing axially relative driven gear, in that it comprises the features.

  Further, the gear mechanism of the present invention is arranged so as to be axially opposed to the first gear fixed to the casing, coaxially with the first gear, and to be rotatable with respect to the casing and in the axial direction. A relatively fixed second gear, the first gear and a rotatable first shaft provided coaxially with the second gear, and an inclined surface with respect to the first shaft The tilted shaft is disposed between the first gear and the second gear, and is provided rotatably with respect to the tilted shaft. A rocking gear meshing with a fixed inclination angle is provided coaxially with the first shaft, a second shaft rotating integrally with the second gear, and coaxial with the second gear. The moving gear is disposed on the same axial side as the first gear, and meshes with the swinging gear. While being rotationally fixed relative to the second gear, characterized in that it comprises a second biasing gear for biasing in the axial direction with respect to the rocking gear.

  The gear mechanism of the present invention includes a first gear fixed to a casing, a coaxial gear with the first gear and facing the same side in the axial direction. A second gear relatively fixed in the direction, a first rotatable shaft provided coaxially with the first gear and the second gear, and an inclination with respect to the first shaft. An inclined shaft provided on one side in the axial direction with respect to the first gear and the second gear, and provided rotatably with respect to the inclined shaft, and the first gear and A swing gear that meshes with the second gear at a fixed inclination angle, a second shaft that is provided coaxially with the first shaft and rotates integrally with the second gear, and the first gear The first gear is provided coaxially with the first gear. It is to rotationally fixed, characterized in that and a first biasing gear for urging the axial direction with respect to the rocking gear.

  The gear mechanism of the present invention includes a first gear fixed to a casing, a coaxial gear with the first gear and facing the same side in the axial direction. A second gear relatively fixed in the direction, a first rotatable shaft provided coaxially with the first gear and the second gear, and an inclination with respect to the first shaft. An inclined shaft provided on one side in the axial direction with respect to the first gear and the second gear, and provided rotatably with respect to the inclined shaft, and the first gear and A swing gear that meshes with the second gear at a fixed inclination angle, a second shaft that is provided coaxially with the first shaft and rotates integrally with the second gear, and the second gear It is coaxial with the second gear and is arranged on the same axial side as the second gear with respect to the swing gear. A second urging gear that meshes with the oscillating gear, is fixed in a rotational direction with respect to the second gear, and urges the oscillating gear in the axial direction. Features.

  According to the present invention, while the first gear and the second gear are engaged with the swing gear, at least one of the first urging gear and the second urging gear is engaged while being urged in the axial direction. It becomes like this. Therefore, the torsional rigidity is maintained when the first gear and the second gear mesh with the swing gear. Further, at least one of the first urging gear and the second urging gear meshes with each other while urging the swinging gear in the axial direction, thereby reducing backlash of the meshing portion and rotational angle transmission accuracy due to wear of the tooth surface. Can be prevented. Thereby, according to this invention, backlash etc. can be suppressed, without causing the fall of torsional rigidity.

1 is a perspective view showing a schematic configuration of a robot apparatus according to a first embodiment of the present invention. It is a longitudinal section showing a schematic structure of a reduction gear concerning a 1st embodiment of the present invention. It is a side view showing a schematic structure of the 1st energizing gear, the 2nd energizing gear, and the rocking gear of the reduction gear concerning a 1st embodiment of the present invention. It is a longitudinal cross-sectional view which shows schematic structure of the 1st urging gear and 2nd urging | biasing gear of the reduction gear which concerns on 1st Embodiment of this invention, (a) is each tooth surface protruding from a reference position. In the case (b), each tooth surface does not protrude from the reference position. It is a longitudinal cross-sectional view which shows schematic structure of the reduction gear which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows schematic structure of each reduction gear of this invention, (a) is 1st Embodiment, (b) is 2nd Embodiment, (c) is 3rd Embodiment, (d) is 4th. Embodiment, (e) is the fifth embodiment, and (f) is the sixth embodiment.

<First Embodiment>
Hereinafter, the robot apparatus 650 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4. First, a schematic configuration of the robot apparatus 650 according to the first embodiment will be described with reference to FIG.

  The robot apparatus 650 is an industrial robot, and includes an articulated robot 600 that performs operations such as assembly of the workpiece W, a control apparatus 630 that controls the articulated robot 600, a teaching pendant 640 that can be connected to the control apparatus 630, It has.

  The articulated robot 600 includes a six-axis articulated robot arm (hereinafter simply referred to as a robot arm) 601 and an end effector 602 connected to the tip of the robot arm 601.

  The robot arm 601 includes a base portion 603 fixed to a work table, a plurality of links 621 to 626 that transmit displacement and force, and a plurality of joints 611 that connect each of the plurality of links 621 to 626 so as to be capable of turning or rotating. ˜616. The plurality of joints 611 to 616 include a drive motor (not shown), an encoder (not shown) that detects the rotation angle of the rotation shaft of the drive motor, and a speed reducer that reduces the output of the drive motor to increase the torque of the drive motor. (Transmission) 10.

  Further, the plurality of joints 611 to 616 include a joint drive mechanism (not shown) such as a belt and a gear for operating the joints 611 to 616 by the output of the speed reducer 10. That is, the robot arm 601 is connected to at least one of the plurality of joints 611 to 616 with a drive motor, the speed reducer 10 with one shaft connected to the output shaft of the drive motor, and the other shaft. An articulated drive mechanism. The drive motor and the speed reducer 10 constitute an actuator, and the speed reducer 10 will be described in detail later.

  The end effector 602 is a robot hand, and includes a gripping claw 604 that grips the workpiece W, a drive motor (not shown) that drives the gripping claw 604, an encoder (not shown) that detects the rotation angle of the drive motor, and the output of the drive motor. A speed reducer (not shown) that decelerates the motor. Further, the end effector 602 includes a force sensor (not shown) that can detect a stress (reaction force) acting on the gripping claws 604 and the like.

  The control device 630 is configured by a computer and controls the articulated robot 600. The computer constituting the control device 630 includes, for example, a CPU, a RAM that temporarily stores data, a ROM that stores a program for controlling each unit, and an input / output interface circuit. The control device 630 moves the position and orientation of the robot arm 601 and the end effector 602 by supplying the required power required for the operation of the drive motor to the drive motor from a power source main body (not shown). The teaching pendant 640 can be connected to the control device 630, and can input an instruction for driving and controlling the robot arm 601 and the end effector 602.

  In the robot device 650 configured as described above, the control device 630 drives the drive motors of the joints 611 to 616 of the robot arm 601 according to the input settings and the like, so that the end effector 602 is brought into an arbitrary position and orientation. Move or stop. Then, at an arbitrary position and orientation, work such as assembling of the workpiece W is performed by causing the end effector 602 to grip the workpiece W or parts while detecting the stress acting on the grip claw 604 with a force sensor. Yes.

  Next, the speed reducer 10 according to the first embodiment will be described with reference to FIGS. First, a schematic configuration of the speed reducer 10 will be described with reference to FIG. In this embodiment, the case where the transmission of the present invention is applied to the speed reducer 10 is described. However, the present invention is not limited to this, and the transmission may be applied to a speed increaser. .

  As shown in FIG. 2, the speed reducer 10 includes a casing 11 and a gear mechanism 12 including a set of swing gear mechanisms. The gear mechanism 12 includes an input shaft (first shaft, one shaft) 20, an inclined shaft 21, an output shaft (second shaft, the other shaft) 30, a first gear 40, and a second gear. A gear 50, a swing gear 60, a first urging gear 70, and a second urging gear 80 are provided.

  The input shaft 20 is connected to the drive motor, is provided coaxially with the first gear 40 and the second gear 50, is fixed in the axial direction with respect to the casing 11, and is rotatable about the central shaft 20c. It is supported by. The inclined shaft 21 is integrated with and inclined with respect to the input shaft 20, and the central shaft 21 c is inclined with respect to the central shaft 20 c of the input shaft 20 by a predetermined angle. The output shaft 30 is provided coaxially with the input shaft 20, rotates integrally with the second gear 50, and is connected to the plurality of links 621 to 626 via a joint drive mechanism. Each speed reducer 10 decelerates the rotation input from the drive motor and transmits it to the plurality of links 621 to 626. That is, the speed reducer 10 includes one or more sets of gear mechanisms 12, decelerates the rotation input to the input shaft 20, and outputs it from the output shaft 30.

  The first gear 40 is composed of a bevel gear having teeth 41 directed to the swinging gear 60 side, and is fixed to the casing 11. The teeth 41 are formed in an annular shape with the number of teeth as Z1. The first gear 40 includes a stopper 42 and a plurality of guide holes 43 for supporting a first urging gear 70 described later so as to be movable in the axial direction.

  The second gear 50 is disposed coaxially with the first gear 40 with the swinging gear 60 interposed therebetween, and is fixed to the output shaft 30 so as to be rotatable with respect to the casing 11 and relative to the axial direction. It is fixed to. That is, the second gear 50 is supported not to move relative to the casing 11 in the axial direction by being fixed only to the output shaft 30 without being fixed to the casing 11. The second gear 50 is formed of a bevel gear having teeth 51 directed toward the swinging gear 60, and the teeth 51 are formed in an annular shape with the number of teeth being Z2. The second gear 50 includes a stopper 52 and a plurality of guide holes 53 for supporting a second urging gear 80 described later so as to be movable in the axial direction.

  The oscillating gear 60 is disposed between the first gear 40 and the second gear 50, and is provided to be rotatable with respect to the inclined shaft 21 by a bearing 22. The oscillating gear 60 includes first teeth 61 that mesh with the teeth 41 of the first gear 40 and second teeth 62 that mesh with the teeth 51 of the second gear 50, and the tooth surfaces are circular on both surfaces. It consists of a bevel gear formed in an annular shape. The number of teeth of the first teeth 61 is Z1 + 1 (the number of teeth difference from the first gear 40 is 1). The number of teeth of the second tooth 62 is Z2 + 1 (the difference in number of teeth from the second gear 50 is 1), and the diameter of the meshing portion of the first tooth 61 with the tooth 41 of the first gear 40 is the same. It meshes with the second gear 50 on the opposite side of the direction and the axial direction. As a result, the swing gear 60 meshes with the first gear 40 and the second gear 50 at a constant inclination angle.

  As shown in FIGS. 3 and 4A, the first urging gear 70 includes teeth 71, stopper ribs 72, and a plurality of guide pins 73. The first urging gear 70 is coaxial with the first gear 40 and is a swinging gear. 60 on the same side (one side) in the axial direction. The teeth 71 have the same number of teeth as the teeth 41 of the first gear 40, are provided in an annular shape on the outer peripheral side of the teeth 41, and can form a continuous tooth surface together with the teeth 41. For this reason, the first urging gear 70 can mesh with the swing gear 60 together with the first gear 40.

  The stopper rib 72 is annular and protrudes to the outer peripheral side, and can be engaged with the stopper 42 of the first gear 40. The guide pin 73 is provided so as to protrude toward the opposite side of the tooth 71 in the axial direction, and is slidably fitted in the guide hole 43 of the first gear 40. The guide pin 73 is provided with an urging spring 74 made of a compression coil spring. As a result, the first urging gear 70 can move in the axial direction while the rotation is restricted by the guide pin 73 being slidably supported in the guide hole 43, and the first urging gear 70 can move relative to the axial direction. It is supported so as to be slightly tiltable in the tilt direction.

  Further, the first biasing gear 70 is biased in the axial direction by the biasing spring 74 until the stopper rib 72 contacts the stopper 42. Further, when the stopper rib 72 is brought into contact with the stopper 42, the tooth surface of the tooth 71 protrudes by a predetermined amount toward the swing gear 60 from the reference position (indicated by a one-dot chain line in the figure) where the tooth surface of the tooth 41 is extended. Thus, it is located at a close position close to the swing gear 60. Here, the predetermined amount and the magnitude of the urging force of the urging spring 74 can be appropriately set according to the transmission torque of the first gear 40 and the first urging gear 70 and the swinging gear 60 and the like. . Further, when an external force in the axial direction acts on the teeth 71, the first urging gear 70 is pushed in the axial direction against the urging spring 74, and the teeth 71 exceed the reference position with the swinging gear 60. It is pushed into the opposite side and is located at a separated position away from the swing gear 60.

  In other words, the first urging gear 70 is provided coaxially with the first gear 40, meshes with the swing gear 60, and is fixed in the rotational direction with respect to the first gear 40. A force is applied to the shaft 60 in the axial direction. Further, the first biasing gear 70 is movable in the axial direction between a proximity position closer to the swing gear 60 than the reference position and a separation position farther from the swing gear 60 than the reference position. It has become.

  The second urging gear 80 includes teeth 81, stopper ribs 82, and a plurality of guide pins 83, and is provided coaxially with the second gear 50 and on the same axial side with respect to the swinging gear 60. Yes. The teeth 81 have the same number of teeth as the teeth 51 of the second gear 50, are provided in an annular shape on the outer peripheral side of the teeth 51, and can form a continuous tooth surface together with the teeth 51. Therefore, the second urging gear 80 can be engaged with the swing gear 60 together with the second gear 50. The guide pin 83 is provided with an urging spring 84 made of a compression coil spring. That is, the second urging gear 80 is coaxial with the second gear 50 and is disposed on the same side in the axial direction as the second gear 50 with respect to the swing gear 60, and meshes with the swing gear 60. At the same time, it is fixed in the rotational direction with respect to the second gear 50 and biased in the axial direction with respect to the swinging gear 60. Since the operation of the second urging gear 80 is the same as that of the first urging gear 70, detailed description thereof is omitted.

  The input shaft 20, the output shaft 30, the first gear 40, the second gear 50, the swing gear 60, the first urging gear 70, and the second urging gear 80 in the speed reducer 10 of the present embodiment. Each positional relationship is schematically shown in FIG. Further, as the gear material, high-performance reduction gear 10 may be realized using high-performance steel, or low-cost general steel may be used, and non-ferrous metal, sintered material, synthetic resin, or the like is applied. be able to.

  Next, the speed reduction operation by the speed reducer 10 having the gear mechanism 12 described above will be described with reference to FIG.

  When the input shaft 20 rotates once, the inclined shaft 21 rotates and the swing gear 60 swings once. At this time, the swing gear 60 revolves by an angle corresponding to the difference in the number of teeth between the first gear 40 and the swing gear 60. That is, when the input shaft 20 rotates Z1 + 1, the swing gear 60 revolves once. On the other hand, revolution due to swinging also occurs between the second gear 50 and the swinging gear 60. Thereby, the rotational force input from the input shaft 20 is decelerated by the swing gear 60 and output from the output shaft 30.

  In the present embodiment, the first tooth 61 of the rocking gear 60 is one more than the tooth 41 of the first gear 40, and the second tooth 62 of the rocking gear 60 is larger than the tooth 51 of the second gear 50. It is set to be one more. For this reason, in the speed reducer 10, the first gear 40 and the second gear 50 rotate in the opposite directions around the swing gear 60. It is known that the reduction ratio of the reduction gear 10 can be calculated by 1− (Z1 (Z2 + 1)) / ((Z1 + 1) Z2). For example, when Z1 = 24 and Z2 = 48, a reduction ratio of 1/50 is obtained. For example, if Z1 = 48 and Z2 = 49, a large reduction ratio of 1/2401 is possible. The reduction gear 10 can realize a wide range of reduction ratios with a simple gear mechanism 12 by setting the number of teeth, from a reduction speed ratio of about 1/20 to a large reduction ratio of 1/1000. . Further, the reduction gear 10 can be handled as a one-stage differential reduction gear.

  Here, the teeth 71 of the first urging gear 70 protrude toward the oscillating gear 60 from the reference position. However, when the first teeth 61 of the oscillating gear 60 are engaged, the first urging gear 60 is engaged. 70 is pushed against the biasing spring 74. As a result, a preload is applied to the meshing of the first urging gear 70 and the swinging gear 60. The meshing between the oscillating gear 60 and the first gear 40 may cause backlash or contact with an excessive load due to a dimensional error or assembly error of the gear. On the other hand, the meshing of the swinging gear 60 and the first biasing gear 70 is performed by biasing the first biasing gear 70 to the swinging gear 60 by compression of the biasing spring 74 and preloading the meshing. Give and bite. For this reason, the tooth surface position of the tooth 71 of the first urging gear 70 is aligned with the tooth surface position of the first tooth 61 of the swing gear 60 in contact therewith, and backlash or excessive in tooth surface contact is caused. Generation of load can be suppressed.

  When the input shaft 20 rotates, the swing gear 60 swings and rotates by rotating and moving the first teeth 61 along the tooth surfaces of the teeth 41 of the first gear 40. Then, the first biasing gear 70 changes the inclination of its posture in accordance with the presence / absence of the meshing pressure from the tooth surface of the tooth 61 of the rocking gear 60 and the increase / decrease of the pressure accompanying the rocking rotation. Further, by engaging the swing gear 60 with the first gear 40 and the first biasing gear 70, the torsional rigidity can be maintained by the engagement between the first gear 40 and the swing gear 60.

  The second urging gear 80 is the same as the first urging gear 70. That is, the tooth surface position of the tooth 81 of the second urging gear 80 is aligned with the tooth surface position of the second tooth 62 of the swinging gear 60 in contact therewith, and backlash or excessive load is applied to the tooth surface contact. Can be suppressed. Further, by engaging the swing gear 60 with the second gear 50 and the second biasing gear 80, the torsional rigidity can be maintained by the engagement between the second gear 50 and the swing gear 60.

  As described above, according to the reduction gear 10 of the present embodiment, the first urging gear 70 and the second urging gear 70 are engaged while the first gear 40 and the second gear 50 are engaged with the swing gear 60. The biasing gear 80 meshes while being biased in the axial direction. For this reason, when the first gear 40 and the second gear 50 mesh with the swing gear 60, the torsional rigidity is maintained. Further, since the first urging gear 70 and the second urging gear 80 mesh with each other while urging the swinging gear 60 in the axial direction, the backlash of the meshing portion is reduced and the rotation angle transmission accuracy due to wear of the tooth surface is achieved. Can be prevented. Thereby, according to the reduction gear 10 of this embodiment, backlash etc. can be suppressed, without causing a fall of torsional rigidity.

  Further, according to the speed reducer 10 of the present embodiment, the tooth surfaces of the teeth 71 of the first urging gear 70 and the teeth 81 of the second urging gear 80 can protrude from the reference position. For this reason, for example, even if a dimensional error and an assembly accuracy error of the first gear 40, the second gear 50, and the swing gear 60 are relatively large, such an error is caused by the protruding first biasing gear. 70 and the second urging gear 80 can be absorbed. As a result, by using the speed reducer 10 for the joints 611 to 616 of the robot arm 601, it becomes possible to improve the performance of the robot arm 601.

  In the above-described embodiment, the case where the tooth surfaces of the teeth 71 of the first urging gear 70 and the teeth 81 of the second urging gear 80 can protrude from the reference position has been described. Is not limited. For example, as shown in FIG. 4B, when the stopper rib 72 of the first urging gear 70 abuts against the stopper 42, the tooth surface of the tooth 71 of the first urging gear 70 is the first gear. You may make it correspond to the reference position which is the extension of the tooth surface of 40 teeth 41. FIG. In this case, for example, when the teeth 41 of the first gear 40 are worn and the first teeth 61 of the rocking gear 60 are deeply engaged with the teeth 41, the teeth 71 of the first biasing gear 70 are used. Thus, a preload is applied to the swing gear 60. In this case, since the first urging gear 70 does not protrude from the first gear 40, there is no need to consider interference with the first urging gear 70 protruding at the portion where the swing gear 60 does not mesh. The degree of freedom in design can be improved. Since the same applies to the second urging gear 80, detailed description thereof is omitted.

  In the above-described embodiment, the teeth 71 of the first biasing gear 70 are arranged on the outer peripheral side of the teeth 41 of the first gear 40, and the teeth 81 of the second biasing gear 80 are disposed on the second gear. Although the case where it arrange | positions to the outer peripheral side of 50 teeth 51 was demonstrated, it is not restricted to this. For example, the teeth 71 of the first biasing gear 70 are arranged on the inner peripheral side of the teeth 41 of the first gear 40, or the teeth 81 of the second biasing gear 80 are replaced with the teeth 51 of the second gear 50. You may arrange | position on the inner peripheral side.

  In the above-described embodiment, the case where both the first urging gear 70 for the first gear 40 and the second urging gear 80 for the second gear 50 are provided has been described. Is not limited. By providing at least one of the first urging gear 70 and the second urging gear 80, it is possible to suppress backlash and the like without causing a decrease in torsional rigidity.

  In the above-described embodiment, the speed reducer 10 includes a set of gear mechanisms 12, but is not limited thereto, and may include a plurality of gear mechanisms 12.

  Moreover, although it does not specifically limit about a tooth shape in embodiment mentioned above, a suitable tooth shape can be applied according to design. For example, a tooth shape that contacts almost the entire circumference, or, for example, in order to separate the vicinity of the passing position and the vicinity of the most meshing position where the pressure angle is large and does not contribute to torque transmission, from the tip portion of the tooth tip and the concave portion of the tooth root It may be a tooth mold that has been scraped off. Or let the front-end | tip part of one tooth | gear be a circular arc shape with constant radius, and let the curve calculated | required as the circumscribing line (shape which followed the passing area) of the locus | trajectory which this moves around the other party tooth be the other party tooth shape. Then, using the curve obtained as the circumscribing line of the trajectory in which the tip portion of the obtained partner tooth moves around the arc-shaped tooth, the tip portion may have the shape of the arc-shaped tooth.

  In the above-described embodiment, the case where the speed reducer 10 is applied to the vertical articulated 6-axis articulated robot arm as the robot arm 601 has been described, but the present invention is not limited thereto. For example, the present invention can also be applied to robots other than 5-axis, 7-axis, horizontal articulated robots, orthogonal robots, and articulated robots. The present invention is not limited to the robot arm 601, but is suitable for other applications such as driving an electric vehicle and a belt conveyor that require small and large torque.

Second Embodiment
Next, a robot apparatus 650 according to a second embodiment of the present invention will be described with reference to FIG. The robot apparatus 650 according to the second embodiment is different from the first embodiment in the configuration of the speed reducer 110. Therefore, in 2nd Embodiment, it demonstrates centering around the reduction gear 110 different from 1st Embodiment, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 5, the speed reducer 110 according to the second embodiment includes an input shaft 120, an output shaft 130, a first gear 140, a second gear 150, a swing gear 160, and a first biasing gear 170. The second urging gear 180 is provided. The speed reducer 110 of the present embodiment is different from the first embodiment in that the first gear 140 and the second gear 150 are arranged on the same side in the axial direction with respect to the swing gear 160. Is different. Further, the speed reducer 110 is different in that the first gear 140 and the first urging gear 170 are disposed on the opposite sides in the axial direction with the swinging gear 160 interposed therebetween.

  The first gear 140 is formed of a bevel gear having teeth 141 directed to the swing gear 160 side, and is fixed to the casing 111. The teeth 141 are formed in an annular shape with the number of teeth as Z1 and mesh with the first teeth 161 of the swing gear 160. Further, a casing 142 on the opposite side of the first gear 140 in the axial direction across the swing gear 160 has a stopper 142 and a plurality of guides for supporting the first urging gear 170 so as to be movable in the axial direction. A hole 143 is formed.

  The first urging gear 170 includes teeth 171, stopper ribs 172, and a plurality of guide pins 173, and is provided coaxially with the first gear 140 and on the opposite side in the axial direction with respect to the swinging gear 160. Yes. The teeth 171 have the same number of teeth as the teeth 141 of the first gear 140, are provided in an annular shape so as to face the teeth 141 with the swinging gear 160 interposed therebetween, and mesh with the second teeth 162 of the swinging gear 160. It is supposed to be. Therefore, the first urging gear 170 can mesh with the swing gear 160 together with the first gear 140. Here, the same number of teeth means the rotation ratio between the tooth 141 of the first gear 140 and the first tooth 161 of the swing gear 160, the tooth 171 of the first biasing gear 170, and the swing gear. This means that the rotation ratio of the 160 second teeth 162 is the same, and is not limited to the actual number of teeth.

  The stopper rib 172 is annular and protrudes to the outer peripheral side, and can engage with the stopper 142 of the casing 111. The guide pin 173 is provided so as to protrude toward the opposite side of the tooth 171 in the axial direction, and is slidably fitted into the guide hole 143 of the casing 111. The guide pin 173 is provided with an urging spring 174 made of a compression coil spring. The teeth 171 are set so as to be able to protrude from the reference position, which is the original position of the gear facing the first gear 140, and are pushed to the opposite side against the biasing spring 174 by the pressing of the swing gear 160. It has become. Since the operation of the first urging gear 170 is the same as that of the first embodiment, detailed description thereof is omitted.

  The oscillating gear 160 is disposed between the first gear 140 and the first urging gear 170, and is provided to be rotatable with respect to the inclined shaft 121 by a bearing 122. In this embodiment, the inclined shaft 121 has a rectangular cross-sectional shape, for example, and is supported so as to be tiltable in the axial direction with respect to the bearing 122 and so as to rotate integrally in the rotational direction. It has become.

  The swing gear 160 includes first teeth 161 that mesh with the teeth 141 of the first gear 140, second teeth 162 that mesh with the teeth 171 of the first biasing gear 170, and the second gear 150. A third tooth 163 that meshes with the tooth 151 and the tooth 181 of the second urging gear 180 is provided. The oscillating gear 160 is formed of a bevel gear having tooth surfaces formed in an annular shape on both sides. The first teeth 161 and the second teeth 162 have the number of teeth Z1 + 1 (the difference in the number of teeth from the first gear 140 and the first biasing gear 170 is 1). The number of teeth of the third tooth 163 is Z2 + 1 (the number of teeth difference between the second gear 150 and the second biasing gear 180 is 1). As a result, the swing gear 160 meshes with the first gear 140 and the first biasing gear 170 at a constant inclination angle.

  The second gear 150 is coaxial with the first gear 140 and is disposed on the same side in the axial direction with respect to the swinging gear 160, and is fixed to the casing 111 by being fixed to the output shaft 130 in the axial direction. ing. The second gear 150 is composed of a bevel gear having teeth 151 directed toward the swing gear 160, and the teeth 151 are formed in an annular shape with the number of teeth being Z2. The second gear 150 includes a stopper 152 and a plurality of guide holes 153 for supporting the second urging gear 180 so as to be movable in the axial direction.

  The second urging gear 180 includes teeth 181, a plurality of guide pins 183, and a stopper 185, and is provided coaxially with the second gear 150 and on the same axial side with respect to the swinging gear 160. Yes. The teeth 181 have the same number of teeth as the teeth 151 of the second gear 150, and are provided in an annular shape on the inner peripheral side of the teeth 151, so that a continuous tooth surface can be formed together with the teeth 151. Therefore, the second urging gear 180 can mesh with the third gear 163 of the swing gear 160 together with the second gear 150.

  The input shaft 120, the output shaft 130, the first gear 140, the second gear 150, the swing gear 160, the first biasing gear 170, and the second biasing gear 180 in the speed reducer 110 of the present embodiment. Each positional relationship is schematically shown in FIG.

  Next, the speed reduction operation by the speed reducer 110 having the above-described gear mechanism 112 will be described with reference to FIG.

  The teeth 171 of the first urging gear 170 protrude from the reference position toward the oscillating gear 160, and when the second teeth 162 of the oscillating gear 160 are engaged, the first urging gear 170 is energized. It is pushed against the spring 174. As a result, a preload is applied to the meshing between the first urging gear 170 and the swinging gear 160. The meshing between the oscillating gear 160 and the first gear 140 may cause backlash or contact with an excessive load due to a dimensional error or assembly error of the gear. On the other hand, the meshing between the rocking gear 160 and the first biasing gear 170 is such that the first biasing gear 170 is biased toward the rocking gear 160 by the compression of the biasing spring 174, and a preload is applied to the meshing. Give and bite. For this reason, since the tooth 171 of the first biasing gear 170 presses the swing gear 160, the swing gear 160 is pressed against the first gear 140, so backlash in tooth surface contact or excessive load is caused. Occurrence can be suppressed.

  When the input shaft 120 rotates, the swing gear 160 swings and rotates by rotating the first tooth 161 along the tooth surface of the tooth 141 of the first gear 140. The first urging gear 170 changes the inclination of the posture according to the presence / absence of the meshing pressure from the tooth surface of the tooth 161 of the rocking gear 160 and the increase / decrease of the pressure accompanying the rocking rotation. Further, by engaging the first gear 140 and the first biasing gear 170 so as to sandwich the swing gear 160, the torsional rigidity is maintained by the engagement of the first gear 140 and the swing gear 160. Can do.

  The second urging gear 180 is the same as in the first embodiment. That is, the tooth surface position of the tooth 181 of the second urging gear 180 is aligned with the tooth surface position of the third tooth 163 of the swinging gear 160 in contact therewith, and backlash or excessive load is applied to the tooth surface contact. Can be suppressed. Further, by engaging the swing gear 160 with the second gear 150 and the second biasing gear 180, the torsional rigidity can be maintained by the engagement between the second gear 150 and the swing gear 160.

  As described above, the torsional rigidity is maintained by the reduction gear 110 of the present embodiment as well as the first gear 140 and the second gear 150 are engaged with the swing gear 160 as in the first embodiment. Will come to be. Further, the first urging gear 170 and the second urging gear 180 mesh with each other while urging the swing gear 160 in the axial direction, thereby reducing backlash of the meshing portion and rotational angle transmission accuracy due to wear of the tooth surface. Can be prevented.

  Moreover, although embodiment mentioned above demonstrated the case where the tooth | gear 181 of the 2nd biasing gear 180 was arrange | positioned at the inner peripheral side of the tooth | gear 151 of the 2nd gear 150, it is not restricted to this. For example, the teeth 181 of the second biasing gear 180 may be arranged on the outer peripheral side of the teeth 151 of the second gear 150.

  In the above-described embodiment, the case where both the first urging gear 170 for the first gear 140 and the second urging gear 180 for the second gear 150 are provided has been described. Is not limited. By providing at least one of the first urging gear 170 and the second urging gear 180, backlash and the like can be suppressed without causing a decrease in torsional rigidity.

<Third Embodiment>
Next, a robot apparatus 650 according to a third embodiment of the present invention will be described with reference to FIG. The robot apparatus 650 according to the third embodiment is different from the first embodiment in the configuration of the speed reducer 210. Therefore, in 3rd Embodiment, it demonstrates centering around the reduction gear 210 different from 1st Embodiment, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 6C, the speed reducer 210 of the present embodiment includes an input shaft 220, an output shaft 230, a first gear 240, a second gear 250, a swing gear 260, and a first biasing gear. 270 and a second urging gear 280. The first gear 240 is fixed to the casing. The first urging gear 270 is disposed coaxially with the first gear 240 and on the opposite side in the axial direction with respect to the swing gear 260. The second gear 250 is disposed coaxially with the first urging gear 270 with respect to the swing gear 260 and on the same side in the axial direction. The second urging gear 280 is disposed on the inner peripheral side or the outer peripheral side on the same side as the second gear 250 and in the same axial direction with respect to the swing gear 260. Note that the detailed configuration and operation of each part are the same as those in the first and second embodiments, and thus detailed description thereof is omitted.

  As described above, the torsional rigidity is maintained by the reduction gear 210 of the present embodiment as well as the first gear 240 and the second gear 250 are engaged with the swinging gear 260 as in the first embodiment. Will come to be. Further, the first urging gear 270 and the second urging gear 280 mesh with each other while urging the swing gear 260 in the axial direction, thereby reducing the backlash of the meshing portion and the rotational angle transmission accuracy due to wear of the tooth surface. Can be prevented.

  In the above-described embodiment, the case where both the first urging gear 270 for the first gear 240 and the second urging gear 280 for the second gear 250 are described has been described. Is not limited. By providing at least one of the first urging gear 270 and the second urging gear 280, backlash and the like can be suppressed without causing a decrease in torsional rigidity.

<Fourth embodiment>
Next, a robot apparatus 650 according to a fourth embodiment of the present invention will be described with reference to FIG. The robot apparatus 650 according to the fourth embodiment is different from the first embodiment in the configuration of the speed reducer 310. Therefore, in 4th Embodiment, it demonstrates centering around the reduction gear 310 different from 1st Embodiment, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 6D, the speed reducer 310 of the present embodiment includes an input shaft 320, an output shaft 330, a first gear 340, a second gear 350, a swing gear 360, and a first biasing gear. 370 and a second urging gear 380 are provided. The first gear 340 is fixed to the casing. The second gear 350 is disposed coaxially with the first gear 340 and on the same axial side with respect to the swing gear 360. The first urging gear 370 is disposed on the inner peripheral side or the outer peripheral side on the same side as the first gear 340 and in the same axial direction with respect to the swing gear 360. The second urging gear 380 is disposed on the inner peripheral side or the outer peripheral side on the same side as the second gear 350 and in the same axial direction with respect to the swing gear 360. Note that the detailed configuration and operation of each part are the same as those in the first and second embodiments, and thus detailed description thereof is omitted.

  As described above, the torsional rigidity is maintained by the reduction gear 310 of the present embodiment as well as the first gear 340 and the second gear 350 are engaged with the swing gear 360 in the same manner as in the first embodiment. Will come to be. Further, the first urging gear 370 and the second urging gear 380 mesh with each other while urging the swinging gear 360 in the axial direction, thereby reducing the backlash of the meshing portion and the rotational angle transmission accuracy due to wear of the tooth surface. Can be prevented.

  In the above-described embodiment, the case where both the first urging gear 370 with respect to the first gear 340 and the second urging gear 380 with respect to the second gear 350 has been described. Is not limited. By providing at least one of the first urging gear 370 and the second urging gear 380, it is possible to suppress backlash and the like without causing a decrease in torsional rigidity.

<Fifth Embodiment>
Next, a robot apparatus 650 according to a fifth embodiment of the present invention will be described with reference to FIG. The robot apparatus 650 according to the fifth embodiment is different from the first embodiment in the configuration of the speed reducer 410. Therefore, in 5th Embodiment, it demonstrates centering around the reduction gear 410 different from 1st Embodiment, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 6E, the speed reducer 410 of this embodiment includes an input shaft 420, an output shaft 430, a first gear 440, a swing gear 460, and a first biasing gear 470. The first gear 440 is fixed to the casing. The first urging gear 470 is disposed on the inner peripheral side or the outer peripheral side on the same side as the first gear 440 and in the same axial direction with respect to the swing gear 460. Note that the detailed configuration and operation of each part are the same as those in the first and second embodiments, and thus detailed description thereof is omitted.

  As described above, the torsional rigidity is maintained by the reduction gear 410 of the present embodiment as well as the first gear 340 meshes with the swing gear 360, as in the first embodiment. Further, the first urging gear 370 meshes with the oscillating gear 360 while urging the oscillating gear 360 in the axial direction, so that backlash of the meshing portion can be reduced and rotation angle transmission accuracy can be prevented from being lowered due to tooth surface wear. .

<Sixth Embodiment>
Next, a robot apparatus 650 according to a sixth embodiment of the present invention will be described with reference to FIG. The robot apparatus 650 according to the sixth embodiment is different from the first embodiment in the configuration of the speed reducer 510. Therefore, in 6th Embodiment, it demonstrates centering around the reduction gear 510 different from 1st Embodiment, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 6 (f), the speed reducer 510 of the present embodiment includes an input shaft 520, an output shaft 530, a first gear 540, a swing gear 560, and a first urging gear 570. The first gear 540 is fixed to the casing. The first urging gear 570 is disposed coaxially with the first gear 540 and on the opposite side in the axial direction with respect to the swing gear 560. Note that the detailed configuration and operation of each part are the same as those in the first and second embodiments, and thus detailed description thereof is omitted.

  As described above, the torsional rigidity is maintained by the reduction gear 510 of the present embodiment as well as the first gear 540 is engaged with the swinging gear 560 as in the first embodiment. Further, the first urging gear 570 meshes with the oscillating gear 560 while urging the oscillating gear 560 in the axial direction, so that backlash of the meshing portion can be reduced and rotation angle transmission accuracy can be prevented from being lowered due to wear of the tooth surface. .

DESCRIPTION OF SYMBOLS 10 ... Reduction gear (transmission), 11, 111 ... Casing, 12 ... Reduction mechanism (gear mechanism), 20, 120, 220, 320, 420, 520 ... Input shaft (first shaft, one shaft), 21 , 121... Tilt axis, 30, 130, 230, 330, 430, 530... Output shaft (second axis, other axis), 40, 140, 240, 340, 440, 540. 150, 250, 350 ... second gear, 60, 160, 260, 360, 460, 560 ... swinging gear, 70, 170, 270, 370, 470, 570 ... first biasing gear, 80, 180, 280, 380 ... second biasing gear, 601 ... articulated robot arm, 611-616 ... joint, 621-626 ... link

Claims (18)

A first gear fixed to the casing;
A second gear that is coaxially arranged with the first gear and facing the axial direction, is rotatable with respect to the casing and is relatively fixed in the axial direction;
A rotatable first shaft provided coaxially with the first gear and the second gear;
An inclined axis provided inclined with respect to the first axis;
The first gear and the second gear are disposed between the first gear and the second gear so as to be rotatable with respect to the tilt shaft, and mesh with the first gear and the second gear at a constant tilt angle. A swinging gear,
A second shaft provided coaxially with the first shaft and rotating integrally with the second gear;
The first gear is provided coaxially with the first gear, meshes with the swing gear, is fixed in a rotational direction with respect to the first gear, and is biased in an axial direction with respect to the swing gear. 1 biasing gear,
A gear mechanism characterized by that. It is coaxial with the second gear, is disposed on the same side of the swing gear as the second gear, and meshes with the swing gear, and with respect to the second gear. A second biasing gear fixed in the rotational direction and biasing in the axial direction with respect to the swinging gear,
The gear mechanism according to claim 1. The first biasing gear is disposed on the same side in the axial direction as the first gear with respect to the swinging gear.
The gear mechanism according to claim 1 or 2, characterized in that The first urging gear is disposed on the opposite side of the first gear in the axial direction across the swing gear.
The gear mechanism according to claim 1 or 2, characterized in that A first gear fixed to the casing;
A second gear that is coaxially arranged with the first gear and facing the axial direction, is rotatable with respect to the casing and is relatively fixed in the axial direction;
A rotatable first shaft provided coaxially with the first gear and the second gear;
An inclined axis provided inclined with respect to the first axis;
The first gear and the second gear are disposed between the first gear and the second gear so as to be rotatable with respect to the tilt shaft, and mesh with the first gear and the second gear at a constant tilt angle. A swinging gear,
A second shaft provided coaxially with the first shaft and rotating integrally with the second gear;
It is coaxial with the second gear, is disposed on the same side of the swing gear as the second gear, and meshes with the swing gear, and with respect to the second gear. A second biasing gear fixed in the rotational direction and biasing in the axial direction with respect to the swinging gear,
A gear mechanism characterized by that. A first gear fixed to the casing;
A second gear that is coaxial with the first gear and faces the same side in the axial direction, is rotatable with respect to the casing and is relatively fixed in the axial direction;
A rotatable first shaft provided coaxially with the first gear and the second gear;
An inclined axis provided inclined with respect to the first axis;
The first gear and the second gear are arranged on one side in the axial direction, are provided to be rotatable with respect to the inclined shaft, and with respect to the first gear and the second gear. An oscillating gear meshing at a constant inclination angle;
A second shaft provided coaxially with the first shaft and rotating integrally with the second gear;
The first gear is provided coaxially with the first gear, meshes with the swing gear, is fixed in a rotational direction with respect to the first gear, and is biased in an axial direction with respect to the swing gear. 1 biasing gear,
A gear mechanism characterized by that. It is coaxial with the second gear, is disposed on the same side of the swing gear as the second gear, and meshes with the swing gear, and with respect to the second gear. A second biasing gear fixed in the rotational direction and biasing in the axial direction with respect to the swinging gear,
The gear mechanism according to claim 6. The first biasing gear is disposed on the same side in the axial direction as the first gear with respect to the swinging gear.
The gear mechanism according to claim 6 or 7, wherein: The first urging gear is disposed on the opposite side of the first gear in the axial direction across the swing gear.
The gear mechanism according to claim 6 or 7, wherein: A first gear fixed to the casing;
A second gear that is coaxial with the first gear and faces the same side in the axial direction, is rotatable with respect to the casing and is relatively fixed in the axial direction;
A rotatable first shaft provided coaxially with the first gear and the second gear;
An inclined axis provided inclined with respect to the first axis;
The first gear and the second gear are arranged on one side in the axial direction, are provided to be rotatable with respect to the inclined shaft, and with respect to the first gear and the second gear. An oscillating gear meshing at a constant inclination angle;
A second shaft provided coaxially with the first shaft and rotating integrally with the second gear;
It is coaxial with the second gear, is disposed on the same side of the swing gear as the second gear, and meshes with the swing gear, and with respect to the second gear. A second biasing gear fixed in the rotational direction and biasing in the axial direction with respect to the swinging gear,
A gear mechanism characterized by that. A first gear fixed to the casing;
A rotatable first shaft provided coaxially with the first gear;
An inclined axis provided inclined with respect to the first axis;
An oscillating gear disposed opposite to the first gear and rotatably provided with respect to the tilt axis, and meshing with the first gear at a constant tilt angle;
A second shaft provided coaxially with the first shaft and rotating integrally with the swing gear;
Provided coaxially with the first gear on the same axial side as the first gear with respect to the oscillating gear, and meshed with the oscillating gear from the same axial side as the first gear. And a first urging gear fixed in the rotational direction with respect to the first gear and urging in the axial direction with respect to the swinging gear.
A gear mechanism characterized by that. A first gear fixed to the casing;
A rotatable first shaft provided coaxially with the first gear;
An inclined axis provided inclined with respect to the first axis;
An oscillating gear disposed opposite to the first gear and rotatably provided with respect to the tilt axis, and meshing with the first gear at a constant tilt angle;
A second shaft provided coaxially with the first shaft and rotating integrally with the swing gear;
Provided coaxially with the first gear on the opposite side of the first gear with respect to the swing gear, and meshed with the swing gear from the opposite side of the first gear in the axial direction. And a first urging gear fixed in the rotational direction with respect to the first gear and urging in the axial direction with respect to the swinging gear.
A gear mechanism characterized by that. The first biasing gear is movable in an axial direction between a proximity position closer to the swing gear than a predetermined reference position and a separation position that is farther from the swing gear than the reference position. Is,
The gear mechanism according to any one of claims 1 to 4, claim 6 to 9, claim 11, or claim 12. The first gear is movable in the axial direction between a predetermined reference position and a separation position that is further away from the swing gear than the reference position.
The gear mechanism according to any one of claims 1 to 4, claim 6 to 9, claim 11, or claim 12. The second urging gear is movable in the axial direction between a proximity position closer to the swing gear than a predetermined reference position and a separation position that is farther from the swing gear than the reference position. Is,
The gear mechanism according to any one of claims 2, 5, 7, and 10. The second gear is movable in the axial direction between a predetermined reference position and a separation position that is farther from the swing gear than the reference position.
The gear mechanism according to any one of claims 2, 5, 7, and 10. One or more sets of the gear mechanism according to any one of claims 1 to 16, wherein the rotation input to one of the first shaft and the second shaft is shifted, and the other shaft is rotated. Output,
A transmission characterized by that. 18. A plurality of joints that connect a plurality of links to each other, and at least one of the plurality of joints is connected to a drive motor and the one shaft to an output shaft of the drive motor. And a joint drive mechanism connected to the other shaft,
An articulated robot arm.

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