JPH0637221Y2 - Rotary friction drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a rotary friction drive device for rotating a rotating body through a friction roller at a predetermined reduction ratio, for example, a joint portion of an articulated robot. The present invention relates to a rotary friction drive device used in.

[Prior Art] Conventionally, as a rotary friction drive device used in an articulated robot or the like, for example, as shown in JP-A-60-161083, the rotational force from a drive motor is transmitted through a reduction gear. The method of doing is known. However, in the method of transmitting the driving force via the gear in this way,
There is a problem in terms of rotational positioning accuracy and durability due to backlash that the gear originally has and wear of the gear tooth surface.

Therefore, as a rotary friction drive device that does not use a gear, for example, as shown in Japanese Patent Publication No. 62-46742, there is a planetary roller type power transmission device that transmits power by frictional force of rollers contacting each other. To do. In this planetary roller power transmission device, by providing a thick portion on the outer peripheral portion, the neutral surface is positioned closer to the outer peripheral portion, the deformability of the contact portion with the mating roller is increased, and even with a small axial pressing force. In order to obtain a large pressure contact force, and to use a mechanical pressurizing means without using hydraulic pressure, it is an object to achieve a simple structure and cost reduction.

In order to achieve the above-mentioned object, this conventional planetary roller power transmission device is provided with an elastic roller so that a frictional force is generated between the plurality of planetary rollers and the sun roller based on the elastic deformation of the elastic roller. It is configured.

[Problems to be Solved by the Invention] However, in such a conventional planetary roller power transmission device, since a plurality of planetary rollers are brought into contact with the sun roller, the diameter dimensions of the plurality of planetary rollers are different. If so, it is practically impossible to make rolling contact with the sun roller, and as a result, the rotation transmission cannot be balanced. Further, extreme wear occurs in the planetary roller having a large diameter dimension. In addition, the pressing force on the side where the planetary roller with a large diameter comes into contact increases,
It is conceivable that a biased force acts on the bearing that supports the sun roller or the ring roller, which shortens the life of the bearing.

Further, since the elastic roller has a very small deformation amount, when the elastic roller is worn due to long-term use, slippage occurs between the elastic roller and the planetary roller. When slip occurs between the planetary roller and the planetary roller as described above, the transmission torque is reduced. Therefore, when slippage occurs, the amount of elastic deformation of the elastic roller must be adjusted again, which causes a problem in maintenance and inspection.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to have a simple structure, and even if the friction roller is worn, it is possible to satisfactorily transmit the rotational force. (EN) Provided is a rotary friction drive device which can be easily maintained and inspected.

Another object of the present invention is to provide a rotary friction drive device capable of preventing the life of the bearing from being shortened without exerting a biased force on the bearing.

Further, the present invention relates to a rotary friction drive device suitable for application to a rotary drive force transmission device of a robot, particularly a vertical multi-joint type or scalar type joint robot.

Such a joint robot has a large load load for gripping and carrying heavy objects, and in the rotation transmission by the elastic roller described above, the elastic deformation amount varies due to the load load. Therefore, there is a problem that it is difficult to compensate the accuracy of movement control of the movable portion.

A second object of the present invention is to provide the rotating body, the friction roller that is brought into pressure contact with the rotating body, and the drive roller that transmits the driving force from the drive source to the rotating body with a rigid rigid body. An object of the present invention is to provide a rotary friction drive device capable of ensuring the rotation control of a rotating body with high accuracy.

[Means for Solving the Problems] In order to solve the problems described above and achieve the object, a rotary friction drive device according to the present invention has one end side upright on a base and the other end having a load portion. In a rotary friction drive device for rotationally driving a shaft portion, a substantially disk-shaped rotating body that is fixed to a lower end portion of the upright shaft portion and is rotatably supported in a horizontal plane with respect to the base, A drive roller that rotates on the outer peripheral cylindrical surface of the rotating body to drive the rotating body, and a drive housing that rotatably supports the drive roller,
A drive motor that is fixed to the drive housing and that generates a drive force that causes the drive roller to rotate the rotating body, and is disposed at a position that substantially opposes the drive roller about a rotation center of the rotating body, A pressure contact roller that rolls on the outer peripheral cylindrical surface of the rotating body, a roller support member that rotatably supports the pressure contact roller, and is arranged on the base.
An engaging portion that guides the drive housing so as to move toward and away from the outer peripheral cylindrical surface of the rotating body and immovably in the rotating direction of the rotating body, and the roller support member for the outer peripheral cylindrical surface of the rotating body. A spring mechanism for urging the pressure mechanism to press against each other, a pressure contact housing that is urged by a reaction force of the spring mechanism in a direction away from the outer peripheral cylindrical surface of the rotating body, and the pressure contact housing and the drive housing A reaction force of the connecting rod that connects the connecting rod and the pressing roller, which is generated by the spring mechanism, to the outer peripheral cylindrical surface of the rotating body is applied to the drive housing through the pressing housing and the connecting rod. Then, the reaction force urges the drive housing toward the outer peripheral cylindrical surface of the rotating body, and the drive roller is pressed against the outer peripheral cylindrical surface of the rotating body. It is characterized by causing.

[Operation] In the rotary friction drive device configured as described above, the drive housing supporting the drive roller and the pressure contact housing are connected by the connecting rod, and the reaction force for pressing the pressure contact roller against the outer peripheral cylindrical surface of the rotating body is used. Then, the drive roller is pressed against the outer peripheral cylindrical surface of the rotating body. As a result, the pressure contact roller and the drive roller are always in pressure contact with the outer peripheral cylindrical surface of the rotating body, and even if the pressure contact roller or the drive roller is worn, the pressure contact state between the rotating body, the pressure contact roller and the drive roller is maintained. Thus, the rotational force of the drive roller can be satisfactorily transmitted to the rotating body. Further, since the reaction force that presses the pressure contact roller against the cylindrical surface becomes the pressing force that presses the drive roller against the cylindrical surface, the force that presses the pressure contact roller and the drive roller against the rotating body is an external force against the bearing of the rotating body. Therefore, it is possible to prevent the biased force from acting on the bearing of the rotating body and shorten the life of the bearing.

[Embodiment] In the following, the configuration of the first embodiment of the rotary friction drive device according to the present invention is applied to an articulated robot,
A detailed description will be given with reference to FIGS. 1 to 8 of the accompanying drawings.

First, as shown in FIGS. 1 and 2, the articulated robot 10 is configured in a horizontal scalar type, and a base 12 formed on a base (not shown), and on the base 12, A standing shaft portion that is rotatably mounted around a vertical axis and is rotationally driven through a rotary friction drive device 14 that is a feature of the present invention.
16 and. The base end of a horizontally extending first horizontal arm 18 is fixed to the tip of the standing shaft 16. In addition, the tip of the first horizontal arm 18 has a second
The base end of the horizontal arm 20 is rotatably attached. At the tip of this second horizontal arm 20, a vertical arm
22 is attached so as to be rotatable about a vertical axis and vertically movable along the vertical axis. A finger device 26 is attached to the lower end of the vertical arm 22 via a compliance device 24.

The standing shaft portion 16 described above is formed of a hollow cylindrical body, and inside the standing shaft portion 16, a second drive motor 28 for rotationally driving the second horizontal arm 20 with respect to the first horizontal arm 18. Is stored. Also, the first and second horizontal arms 18, 20
Are each formed of a hollow body. An endless belt 30 that stretches the inside of the first horizontal arm 18 and connects the base end of the second horizontal arm 20 and the drive shaft of the drive motor 28 to each other is stretched.

A third drive motor 32a for moving and driving the vertical arm 22 in the vertical direction is provided above the standing shaft portion 16,
A fourth drive motor 32b for rotationally driving is mounted. The driving force of the third and fourth drive motors 32a and 32b is supplied to the vertical arm 22 via a power transmission mechanism (not shown).
It is set to be transmitted to. Further, the finger device 26 described above is driven via a drive mechanism (not shown),
It is configured to grip a component (not shown).

The second to fourth drive motors 28, 32a, 32b are
Although not shown, a rotary encoder for detecting these rotation amounts is attached and connected to a control unit described later.

Next, a rotary friction drive device 14 for rotationally driving the upright shaft portion 16, which is a feature of the present invention, will be described with reference to FIGS. 3 and 4.

As shown in FIG. 3, the rotary friction drive device 14 includes a stepped cylindrical fixed support base 34 fixed to the central portion of the base 12 described above. A ring-shaped rotating body 38 (shown in FIG. 4) is attached to the outer peripheral edge of the upper portion of the fixed support base 34 via a cross roller bearing 36 so as to be rotatable around a vertical axis. An output flange member 40 is fixed to the upper surface of the rotating body 38.
The lower end of the standing shaft portion 16 described above is connected to the upper surface of the so as to rotate integrally therewith.

Here, the left and right ends of the base 12 are movable in the horizontal direction in the drawing due to the anchorage, and the base is also movable.
A press-contact housing 42 and a drive housing 44 are attached to each other so as not to fall downward from 12. The pressure contact housing 42 and the drive housing 44 are connected to each other by four connecting rods 46a,
They are connected to each other via 46b, 46c, 46d. In other words, the press-contact housing 42 and the drive housing 44 are connected to each other through the four connecting rods 46a to 46d so as to move integrally in the left-right direction.

The drive housing 44 is formed of a hollow housing whose side surface facing the rotating body 38 is open, and the first drive motor 50 is attached to the upper surface of the drive housing 44 via a mounting stay 48. The first drive motor 50 is provided with a motor shaft 52, which is rotationally driven about a vertical axis, extending downward. The lower end of the motor shaft 52 is connected to the upper end of a drive shaft 56 via a coupling joint 54.

This drive shaft 56, via a pair of bearings 58a, 58b,
It is attached to the drive housing 44 so as to be rotatable about a vertical axis. Further, the upper end of the drive shaft 56 projects from the drive housing 44 and is taken out above the drive housing 44, and is connected to the coupling joint 54 as described above. A drive roller 60 as a friction roller that is in rolling contact with the outer peripheral surface of the rotating body 38 is coaxially fixed to a portion of the drive shaft 56 sandwiched between the bearings 58a and 58b. In this way, the upper and lower ends of the drive roller 60 are connected to the bearings 58a, 58a.
Since it is rotatably supported by b, it is possible to reliably prevent the rotation axis from collapsing when it rolls against the rotating body 38 in a pressure contact state.

On the other hand, the pressure contact housing 42 described above is also the drive housing 44.
Similarly to the above, it is formed of a hollow housing whose side surface facing the rotating body 38 is open. In this pressure contact housing 42,
A roller support member 62 is arranged so as to be slidable along the extending direction of a predetermined diameter. The roller support member 62 includes
A pair of pressure contact rollers 64, 64 are rotatably supported as friction rollers via corresponding support shafts 64a, 64b so as to be rotatable about a vertical axis. These pressure rollers 64, 66 are arranged so as to be in rolling contact with the outer peripheral surface of the rotating body 38 described above.

Here, in the drive roller 60 and the pressure contact rollers 64 and 66 as the friction rollers, their outer peripheral surfaces are formed to bulge outward in the radial direction like a drum. On the other hand, the outer peripheral surface of the rotating body 38 on which the rollers 60, 64, 66 are in rolling contact, similarly,
It is shaped like a drum. In this way each roller 60, 64, 66
By forming the rolling contact surface between the and the rotating body 38 in a drum shape,
Even if the rotation axes of the rollers 60, 64, 66 are tilted, the rollers will roll at a point near the center in the vertical direction, maintaining a good contact condition and reducing the roller's unevenness. Is prevented, and the life of the roller can be extended.

In the pressure contact housing 42, the roller support member 62 is urged toward the rotating body 38 along the extending direction, and both pressure contact rollers 64 and 66 supported by the roller supporting member 62 are provided on the outer peripheral surface of the rotating body 38. A spring mechanism 68 is provided so as to press-contact with a predetermined biasing force. The spring mechanism 68 is built up by stacking a plurality of disc springs in a state where they are alternately reversed. These disc springs are set to exert a biasing force in accordance with the bias when released from the compressed state.

Here, a through hole 40a is formed in the central portion of the output flange member 40 that is rotated integrally with the rotating body 38 that is rotationally driven in this way, and in a state of being positioned above this through hole 40a, A first rotary encoder 72 for accurately detecting the rotational position of the rotating body 38 is attached via the attachment stay 70. Further, on the central portion of the fixed support 34, that is,
A fixed shaft 74 for relatively rotationally driving the detection end 72a of the first rotary encoder 72 is fixed on the fixed support base 34 immediately below the first rotary encoder 72 in a vertically extended state. Has been done. The upper end of the fixed shaft 74 penetrates through the through hole 40a and extends immediately below the first rotary encoder 72, and the lower end of the detection end 74a and the lower end of the detection end 74a are connected via a coupling joint 76. Connected to each other.

Since the first rotary encoder 72 is thus provided, the driving force of the first drive motor 50 is
Is transmitted to the rotating body 38 via frictional engagement between the rotating body 38 and
When the rotating body 38 is rotationally driven, the first rotary encoder 72 is also rotated in synchronization with the rotation of the rotating body 38. Here, this first rotary encoder 72
Since the detection end 72a is connected to the fixed shaft 74, the detection end 72a rotates relative to the first rotary encoder 72. In this way, the rotating body 38
The rotational position of 1, that is, the rotational position of the upright shaft portion 16 is accurately detected.

On the other hand, a second rotary encoder 78 and a tachogenerator 80 are both attached to the upper end of the motor shaft 52 of the first drive motor 50. Here, the second rotary encoder 78 is provided to detect the rotation amount of the first drive motor 50, that is, the rotation amount or the rotation position of the drive roller 60, and the tachogenerator 80 is used to rotate the drive roller 60. It is provided to detect speed.

The detection results of the first and second rotary encoders 72 and 78 and the tachogenerator 80 are sent to a control unit, which will be described later, and used for drive control of the robot 10 in this control unit.

In the rotary friction drive device 14 configured as described above,
The rotation driving operation will be described below.

When the biasing force of the spring mechanism 68 is set in the press-contact housing 42, the roller support member 62 is set in accordance with the set force.
Is biased toward the rotating body 38, and as a result, the pressure contact rollers 64 and 66 supported by the roller supporting member 62 are
Will be pressed against the outer peripheral surface with a predetermined pressing force. on the other hand,
As a reaction force of this pressure contact force, the pressure contact housing 42 is
Will be biased in a direction away from.

As a result, four connecting rods 46a-4
The drive housing 44, which is integrally connected via 6d, is biased in a direction in which the drive housing 44 approaches the rotating body 38. That is, the drive roller 60 axially supported by the drive housing 44
Is pressed against the outer peripheral surface of the rotating body 38 with a predetermined pressing force.

In this manner, when the drive roller 60 is in pressure contact with the outer peripheral surface of the rotating body 38, both are frictionally engaged, and the rotating body 38 is rotationally driven according to the rotation of the drive roller 60.

Next, the control content of the drive control of the articulated robot 10 including the rotary friction drive device 14 configured as described above will be described in detail below.

As shown in FIG. 5, the control system of the articulated robot 10 includes a CPU 82 as a control unit. This CPU
82 includes a first control circuit 86 that controls the rotational drive of the first horizontal arm 18 and a second control circuit 88 that controls the rotational drive of the second horizontal arm 20 via the bus line 84. A third control circuit 90 that controls vertical drive of the vertical arm 22 and a fourth control circuit 92 that controls rotational drive of the vertical arm 22 are connected. Here, the first control circuit 86 is connected to the first drive motor 50, the second control circuit 88 is connected to the second drive motor 28, and the third and fourth control circuits 90, 9 are connected.
2 is connected to the third and fourth drive motors 32a and 32b, respectively.

Further, in the CPU 82, through the same bus line 84, a memory 94 as a storage unit, an operation unit 96 for supporting the control operation with respect to the CPU 82, and a signal input / output control unit The I / O control circuit 98 is connected. Further, an interface circuit 100 is connected to the CPU 82 via the same bus line 84, and the interface circuit 100 includes first and second rotary encoders 72, 78.
Is also connected, and the tachogenerator 80 is connected via the A / D converter 102.

Here, in this control system, for example, a finger device
As shown in FIG. 6, when 26 is moved from the initial position indicated by the reference symbol α to the target position indicated by the reference symbol β, the control operation is set in accordance with the flow chart shown in FIG. . Further, when the finger device 26 is located at the initial position α, the x-axis that functions as a reference axis and the first horizontal arm 18 form an angle θ ₁ , and the first horizontal arm 18 and the second horizontal arm 18 form an angle θ ₁ . It is assumed that the horizontal arm 20 makes an angle θ ₂ . In addition, the finger device 26
Is located at the target position β, the x-axis and the first horizontal arm 18 form an angle θ ₃ , and the first horizontal arm 18 and the second horizontal arm 20 form an angle θ ₄ It is assumed that

Under such conditions, the control system executes the control operation according to the procedure shown in FIG. That is, when this control procedure starts, in step S10, reading of the initial position α and the target position β input via the operation unit 96 is executed. After this, in step S12,
Based on the initial position α and the target position β, based on the correlation stored in advance in the memory 94, the initial position α and the target position β
The angle data θ ₁ , θ ₂ , θ ₃ , θ ₄ of the first and second horizontal arms 18, 20 at and are read respectively. Then, in step S14, the required movement angle Δθ ₁ (= θ ₁ −θ ₃ ) of the first horizontal arm 18 and the required movement angle Δθ ₂ (= θ ₂ −θ ₄ ) of the second horizontal arm 20 are calculated. . After this,
On the basis of the calculation result in step S14, in step S16, the rotation speeds v ₁ and v ₂ of the first and second horizontal arms 18 and ₂₀ are set to the first and second horizontal arms 18 and 2, respectively.
It is calculated so that the operation of 0 ends at the same time.

After that, in step S18, the timer (down counter) is set to 5 msec. Then, in step S20, the current position γ of the finger device 26 is set to the first rotary encoder 72 connected to the rotating body 38 and the second drive motor.
The calculation is performed based on the respective detection results from a rotary encoder (not shown) connected to 28. And step
In S22, based on the calculated current position γ,
Through the memory 94, the respective angles θ ₅ and θ ₆ of the first and second horizontal arms 18 and 20 necessary for being located at this current position γ are read.

The angles θ ₅ and θ ₆ will be defined as current values below. Further, the angles θ ₃ and θ ₄ will be defined as target values below. In this control procedure, when this step S20 is first executed, the initial position α
And the current position γ match.

Then, in step S24, the deviation ΔS is calculated from the absolute value of the difference between the target value and the current value. Then, in step S26, it is determined whether this deviation ΔS is smaller than a predetermined threshold value TH. In this step S26, NO
If it is determined that the current value is represented by the threshold value TH, and it is determined that the current value is not within the permissible range to be determined to be the target value, in step S28, the operation in step S16 described above is performed. Based on the respective rotational speeds v ₁ and v ₂
And a drive control signal to the second drive motors 50 and 28.

Then, in step S30, it is determined whether or not the timer has reached zero. When NO is determined in this step S30, that is, when it is determined that the timer has not reached zero yet, this step S30 is repeatedly executed. Then, if YES is determined in this step S30, that is, if it is determined that the timer reaches zero, the process proceeds to the above-mentioned step S18, and the timer is reset to 5 msec.
Is set and the above procedure is repeated.

On the other hand, if YES is determined in step S26 described above, that is, if the deviation ΔS is smaller than the threshold value TH and the target value is within the allowable range, the process proceeds to step S32. Stop the drive control signal output,
A series of control procedures ends.

The robot 10 is drive-controlled by such control contents, but in the robot 10, as described above, even if the drive roller 60 is worn, for example, the drive roller 60 and the rotating body 38 are The rolling contact condition between and is well maintained. However, if the amount of wear of the drive roller 60 becomes excessive, the rolling contact state will be maintained, but the maximum value of the rotation speed of the rotating body 38 will decrease, and the desired performance will deteriorate. Become. Therefore, this first
In the embodiment, independently of the control procedure described above with reference to FIG. 12, for example, the detection control of the wear amount is performed by an interrupt routine that is activated every morning when the power on of the robot 10 is instructed. The operation is set to execute.

The interrupt routine for detecting the wear amount will be described below with reference to FIG.

That is, when the predetermined interrupt timing comes, step S4
At 0, the rotation speed V _{T of the} test run rotor 38 and the rotation angle θ of the rotor 38 previously stored in the memory 94.
_T , the diameter of the drive roller 60 (desired set value) D, and the rotating body
The diameter d of 38 and the number P of pulses output from the second rotary encoder 78 per rotation of the drive roller 60 are read as constants. Here, the above-mentioned rotation speed V _T is set to a slow value such that slippage does not occur between the driving roller 60 and the rotating body 38 which are in rolling contact with each other.

Then, in step S42, the rotating body 38 is rotated by the angle θ _T at the above-described rotational speed V _T with respect to the first control circuit 86.
A control signal is sent to rotate the first drive motor 50 based on the control signal in step S44.
The drive roller 60 is rotationally driven, whereby the rotary body 38 is rotated by the angle θ _T and stopped.

Thereafter, in step S46, the number of pulses N output from the first rotary encoder 72 is detected in order to numerically detect the amount of rotation of the rotating body 38 from the start of rotation to the stop. Then, in step S48, the diameter D'of the actual (current) drive roller 60 is calculated from the following equation based on the pulse number N detected with the rotation of the rotating body 38. That is, wear occurs on both the rotating body 38 and the drive roller 60. Here, since the diameter of the rotating body 38 is sufficiently larger than the diameter of the drive roller 60, the amount of wear of the rotating body 38 is Suppose it can be ignored. Based on this assumption, and assuming that slippage does not occur on both sides as described above,
The distances in which the two rotate and move are equal to each other. As a result, dπ × θ _T / 360 = D′ π × N / P holds. From this equation, D ′ is defined as D ′ = dθ _T P / 360N.

Here, as described above, d, θ _T , P are predetermined constants and N is a detection value, so D ′ is uniquely determined.

Then, in step S50, the difference between the calculated actual diameter D'of the drive roller 60 and the desired set value D of the drive roller 60, that is, the wear amount M is calculated. After that, in step S52, it is determined whether or not the calculated wear amount M is larger than a predetermined allowable value M ₀ .

When it is determined NO in step S52, that is, when the calculated wear amount M is less than or equal to the allowable value M _0, even if the drive control is performed using the drive roller 60, the drive control is substantially performed. Since it is determined that there is no problem, the detection procedure is terminated and the process returns. On the other hand, this step
When YES is determined in S52, that is, when it is determined that the calculated wear amount M is larger than the allowable value M ₀ , the process proceeds to step S54, and in step S54, the alarm operation is executed, The operator is prompted to replace the drive roller 60, and the process returns.

Since the wear amount M of the drive roller 60 can be detected numerically in this way, the drive roller 60 can be replaced when the wear amount M exceeds the allowable value M ₀ .
The maximum speed of the first horizontal arm 18 will always be well maintained at the desired value.

In the embodiment described above, this rotary friction drive device 10
Has been described as being applied to a horizontal scalar type multi-joint robot, the rotary friction drive device according to the present invention is not applied only to such a horizontal scalar type multi-joint robot, but to a vertical scalar type. It can be applied to an articulated robot or a cylindrical light type articulated robot.

Further, in the above-described embodiment, the rotary friction drive device is described as being provided between the base 12 and the upright shaft portion 16, but the present invention is not limited to such a configuration, and is not limited to the first arm. It goes without saying that it may be configured so as to be interposed between the second arm and the second arm.

Further, in the above-described embodiment, the friction roller is 3
Although the present invention has been described as having two rollers (two pressing rollers and one driving roller), the present invention is not limited to such a numerical value, and may be provided with at least two friction rollers. The purpose of the period can be achieved.

[Advantages of the Invention] As described in detail above, the rotary friction drive device according to the present invention has a rotation shaft for rotating and driving the upright shaft portion having one end upright on the base and the load portion on the other end. In the friction drive device, a substantially disk-shaped rotating body that is fixed to the lower end portion of the upright shaft portion and is rotatably supported in the horizontal plane with respect to the base, and is in rolling contact with the outer peripheral cylindrical surface of the rotating body. A drive roller that rotationally drives the rotating body, a drive housing that rotatably supports the drive roller, and a drive motor that is fixed to the drive housing and that generates a driving force that causes the drive roller to rotate the rotating body. A pressure contact roller disposed at a position substantially facing the drive roller about the center of rotation of the rotating body and rollingly contacting an outer peripheral cylindrical surface of the rotating body,
A roller support member that rotatably supports the pressure contact roller, and a roller support member that is disposed on the base and is capable of moving the drive housing in a direction toward and away from an outer peripheral cylindrical surface of the rotating body and in a rotating direction of the rotating body. From the outer peripheral cylindrical surface of the rotating body, an engaging portion that guides immovably, a spring mechanism that urges the roller supporting member to press the outer peripheral cylindrical surface of the rotating body, and a reaction force of the spring mechanism. A pressure contact housing that is biased in the direction of separation, a connecting rod that connects the pressure contact housing and the drive housing to each other, and the pressure contact roller that is generated by the spring mechanism are pressed against the outer peripheral cylindrical surface of the rotating body. A reaction force of the force to be applied to the drive housing via the pressure contact housing and the connecting rod, and the reaction force causes the drive housing to move around the outer circumference of the rotating body. Biased in a direction to approach the cylinder surface, it is characterized in that for pressing the drive roller to the outer peripheral cylindrical surface of the rotating body.

Therefore, according to the present invention, it is possible to provide the rotary friction drive device capable of ensuring the transmission of the driving force even if the pressure contact roller and the drive roller are worn. Further, according to the present invention, the pressure contact roller and the driving roller are made of a rigid body having rigidity, for example, a metal material, so that it can be applied to a rotary friction device such as a robot which requires a medium load driving force. A rotary friction drive will be provided.

Moreover, without biased force acting on the bearing,
Provided is a rotary friction drive device capable of preventing the bearing from having a short life.

[Brief description of drawings]

1 is a front view schematically showing the construction of a horizontal scalar type multi-joint robot to which the first embodiment of the rotary friction drive device according to the present invention is applied; FIG. 2 is a multi-joint shown in FIG. FIG. 3 is a top view showing the structure of the robot in detail; FIG. 3 is a longitudinal sectional view showing the structure of the rotary friction drive device adopted in the multi-joint robot shown in FIG. 1; FIG. 4 is the rotary friction shown in FIG. FIG. 5 is a block diagram showing the structure of the drive unit; FIG. 5 is a block diagram showing the structure of the robot controller; FIG. 6 is a plan view schematically showing the angular positions of the first and second horizontal arms; FIG. 8 is a flow chart showing the basic operation control procedure of the robot; FIG. 8 is a flow chart for detecting the wear amount of the drive roller. In the drawing, 10 ... Articulated robot, 12 ... Base, 14 ... Rotational friction drive device (first embodiment), 16 ... Standing shaft portion, 18 ... First horizontal arm, 20 ... Second horizontal arm, 22 ... Vertical arm, 24
… Compliance device, 26… Finger device, 28… Second
Drive motor, 30 ... Endless belt, 32a ... Third drive motor, 32b ... Fourth drive motor, 34 ... Fixed support base, 3
4a ... Main body, 34b ... Peripheral wall portion, 36 ... Cross roller bearing, 38 ... Rotating body, 38a ... Swelling portion, 40 ... Output flange member, 40a ... Through hole, 42 ... Pressure contact housing, 44 ... Drive housing, 46a-46d ... connecting rod, 48 ... mounting stay, 50 ... first drive motor, 52 ... motor shaft, 54 ... coupling joint, 56 ... drive shaft, 58a; 58b ... bearing, 60 ... drive roller, 62 ... roller support member , 64; 66 ... Pressure contact roller, 68
... Spring mechanism, 68a ... Leaf spring, 70 ... Mounting stay, 72 ... First
Rotary encoder, 72a ... Detecting end, 74 ... Fixed axis, 76
... Coupling joint, 78 ... Second rotary encoder, 80 ... Tachogenerator, 82 ... CPU, 84 ... Bus line, 86 ... First control circuit, 88 ... Second control circuit, 90 ... Third control circuit , 92 ... Fourth control circuit, 94 ... Memory, 96 ...
An operation unit, 98 ... I / O control circuit, 100 ... interface circuit, 102 ... A / D converter.

Claims (1)

[Scope of utility model registration request] 1. A rotary friction drive device for rotationally driving an upright shaft portion having one end upright on a base and a load portion on the other end side, the upright shaft portion being fixed to a lower end portion of the upright shaft portion, A substantially disk-shaped rotating body rotatably supported in a horizontal plane with respect to a base, a drive roller rollingly driving the rotating body by rolling contact with an outer peripheral cylindrical surface of the rotating body, and the drive roller being rotatable. A drive housing for supporting the drive roller, a drive motor fixed to the drive housing for generating a drive force for rotating the rotary body on the drive roller, and a drive motor substantially opposed to the drive roller about a rotation center of the rotary body. And a roller supporting member that rotatably contacts the outer peripheral cylindrical surface of the rotating body, a roller supporting member that rotatably supports the pressing roller, and the drive housing that is disposed on the base and that rotates the rotating body. And an engaging portion that guides the roller support member so as to be movable toward and away from the outer peripheral cylindrical surface of the rotating body and immovably in the rotating direction of the rotating body, and urges the roller supporting member so as to press-contact the outer peripheral cylindrical surface of the rotating body. A spring mechanism, a pressure contact housing that is urged by a reaction force of the spring mechanism in a direction away from the outer peripheral cylindrical surface of the rotating body, a connecting rod that connects the pressure contact housing and the drive housing to each other, A reaction force of a force generated by a spring mechanism for pressing the pressure contact roller against the outer peripheral cylindrical surface of the rotating body is applied to the drive housing via the pressure contact housing and the connecting rod, and the reaction force causes Biasing the drive housing in a direction approaching the outer peripheral cylindrical surface of the rotating body,
A rotary friction drive device, wherein the drive roller is brought into pressure contact with an outer peripheral cylindrical surface of the rotating body.