JPH05169353A - Turning angle index actuator - Google Patents

Abstract

PURPOSE:To make an overall length shortenable and stowable within the desired size, and enable a highly accurate index angle to be secured by a work driving shaft as well as to make a work driving shaft unit easily replaceable. CONSTITUTION:An output shaft of a servomotor 1 is coupled with a sun roller shaft 10 of speed reducing planetary friction roller mechanisms 5-8 by a shaft joint 1, while an output shaft of the speed reducing planetary friction roller mechanisms 5-8 is coupled with a work driving shaft 29 by a shaft joint 26, then the servomotor 1 is driven, transmitting this rotation to the roller mechanisms 5-8, and here rotation of this servomotor 1 is decelerated with an almost constant reduction gear ratio, thus smooth vibrationless rotation is transmitted to a work driving shaft (final turning shaft). At this time, a rotational position of the work driving shaft 29 is detected by a rotational position detector (rotary encoder) 19, and the obtained detection signal is fed to a control part, then a feedback signal obtained at the control part is transmitted to the servomotor 1, thereby controlling this motor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle indexing actuator used for highly accurate rotation angle position control and rotation speed control.

[0002]

2. Description of the Related Art Conventionally, in a servo mechanism, a power transmission device having a drive unit having a speed changing unit and a detecting unit is used.
An example thereof is shown in FIGS. 3 shows a gear reducer of the servo mechanism, FIG. 4 shows a deceleration friction roller mechanism of the servo mechanism, and FIG. 5 shows a deceleration friction roller mechanism of the servo mechanism and a motor.

In FIG. 3, 1 is a motor, 2 is a gear reducer, 3 is an output shaft of the gear reducer 2, 4 is a detector, and the gear reducer 2 is mounted on the output shaft side of the motor 1. .. The rotation of the rotor of the motor 1 is transmitted to the gear reducer 2, reduced in speed, and transmitted to the output shaft 3. At this time, the rotation state of the rotor of the motor 1 is detected by the detector 4 attached to the opposite side of the output shaft of the motor 1.

When this gear reducer 2 is applied to a servo mechanism, highly accurate motion control is hindered by two causes. That is, the first is because of the backlash of the gear reducer 2, regardless of the rotation angle of the rotor of the motor 1,
A rotation angle error corresponding to the backlash always appears on the output shaft 3.

Second, since the detector 4 is attached to the rotor of the motor 1, a rotation angle error corresponding to backlash cannot be detected. On the other hand, in order to detect a rotation angle error corresponding to the backlash, a detector is attached to the output shaft side of the gear reducer 2 and feedback is provided to construct a servo mechanism, and the backlash element is included in the closed loop system. It will get in, and the stability of the servo mechanism will be impaired.

For this reason, a friction roller is used as the deceleration means instead of the gears, a backlash is eliminated, and a detector is provided on the output shaft side of the deceleration means in order to cope with the slip phenomenon of the friction roller. .. There are various types of deceleration friction roller mechanisms that use friction rollers, and as an example, a deceleration planetary friction roller mechanism that uses a planetary roller will be described with reference to FIGS. 4 and 5.

FIG. 4 shows a decelerating planetary friction roller mechanism. 5 is a sun roller, and the outer periphery of the sun roller 5 is
It is in contact with the three planet rollers 6. The opposite sides of the contact points of these three planet rollers 6 to the sun roller 5 are in contact with the inner circumference of the elastic ring 7. Further, the three spindles 8 which are the rotation shafts of the three planetary rollers 6 are engaged with the flange portion of the flange shaft 9.

In this decelerating planetary friction roller mechanism,
For example, when the elastic ring 7 is fixed and the sun roller 5 is rotated, the decelerated rotation is transmitted to the flange shaft 9. On the contrary, when the flange shaft 9 is rotated,
The accelerated rotation is transmitted to the sun roller 5. Figure 5
The deceleration friction roller mechanism and the motor of the same servo mechanism are shown. 1 is a motor, a detector 4 is attached to one end of the motor 1, and the motor rotating shaft 1 is attached to the other end of the motor 1.
There are three. The motor rotation shaft 13 is coupled to the sun roller 10 of the deceleration friction roller mechanism. Further, three planet rollers 6 are located on the outer circumference of the sun roller 10. An elastic ring 7 is located outside these. The elastic ring 7 receives a thrust force through the shim 12 and elastically deforms, so that the inner diameter can be set to an appropriate size.

The spindle 8 which is the rotating shaft of the planetary roller 6 is engaged with the flange portion 11 of the flange shaft 6. An encoder disk 14 is attached to the flange shaft 9. In addition, the encoder disk 14
A transmission type photodetector (not shown) including a light emitting diode and a photodiode is provided. The transmissive photodetector converts the rotation of the flange shaft 9 into an electric pulse train signal. A driven load is coupled near the left end of the flange shaft 9 in the figure. The planetary roller transmission unit is filled with rolling transmission lubricating oil.

In the decelerating planetary friction roller mechanism shown in FIG. 5, after the rotation of the motor 1 is decelerated by the planetary roller reducer, this rotation is transmitted to the load and the load is rotated. At this time, the rotation state of the load is detected without being affected by slips generated between the planetary rollers 6, the sun roller 10, and the elastic ring 7 of the planetary roller reducer.

The use of a planetary roller as the friction roller has the advantage that a large gear ratio can be obtained even with a small volume. Further, it is effective to provide the detectors on both the motor side and the load side of the planetary roller transmission unit in order to improve the control performance. In this way, the rotation angle indexing actuator in which the motor, the decelerating planetary friction roller mechanism, and the detecting means are integrally assembled is replaced with the slip characteristic in which the backlash characteristic changes smoothly according to the magnitude of the load torque. In addition, the rotation state of the load can be detected without being affected by this slip, which enables higher-precision motion control compared to a rotation angle indexing actuator that uses a gear transmission, as well as gear-specific Noise problems are avoided.

FIG. 6 shows another conventional example of the rotation angle indexing actuator. In this rotation angle indexing actuator, individual functional components are arranged in series, and the respective rotary shafts are directly connected. That is, the servo motor 1 is attached to the planetary roller reducer 16 via the connecting housing 18, and the output shaft of the servo motor 1 and the input shaft of the planetary roller reducer 16 are directly connected by the fixed shaft joint 17 to form the planetary roller reducer. The output shaft 9 of 16 and the input shaft 21 of the driven machine are directly connected by the fixed shaft joint 20, the rotary side of the rotary encoder 19 is attached to the output shaft 9, and the fixed side of the rotary encoder 19 is attached to the housing of the planetary roller reducer 16. Installed.

Also in this conventional example, the same operation as the above-described operation is performed, and as a result, the drive rotation function with extremely small fluctuations in rotation speed and slippage during drive operation and the rotary encoder 19 directly attached to the final output shaft are provided. The control function for controlling the servo motor is obtained by feeding back the rotation detection signal of 1), and highly accurate rotation angle position control and rotation speed control are performed.

[0014]

When the conventional rotary angle indexing actuator shown in FIGS. 1 to 6 is applied to an indexing mechanism of a machine tool or the like, the respective constituent parts are arranged in series and the respective rotary shafts are arranged. Since it is directly connected, the total length becomes long and it is difficult to fit the desired size.

The present invention is proposed in view of the above problems, and the object thereof is to shorten the total length and to fit within a desired size. In addition, a highly accurate indexing angle can be obtained with the work drive shaft. Another object is to provide a rotation angle indexing actuator that can easily replace the work drive shaft unit.

[0016]

In order to achieve the above object, the present invention provides a rotation angle indexing actuator having a servo motor, a decelerating planetary friction roller mechanism, and a rotational position detecting means for an output shaft, The output shaft of the servomotor is attached to the sun roller shaft of the decelerating planetary friction roller mechanism, the work drive shaft unit is detachably attached to the housing of the decelerating planetary friction roller mechanism, and the rotation angle indexing spindle shaft is a plurality of bearings. Rotatably supported on the workpiece drive shaft unit via the same, and the same rotation angle indexing spindle shaft and the output shaft of the deceleration planetary friction roller mechanism are detachably attached via the fixed shaft joint, and the fixed shaft joint is attached and detached. A working window is provided in the housing of the decelerating planetary friction roller mechanism, and the rotational position detecting means is attached to the work drive shaft unit.

[0017]

The rotation angle indexing actuator of the present invention is configured as described above, and connects the output shaft of the servomotor and the sun roller shaft of the decelerating planetary friction roller mechanism to form an output shaft of the decelerating planetary friction roller mechanism. And the work drive shaft are connected by a fixed shaft joint, then the servo motor is driven, and this rotation is transmitted to the deceleration planetary friction roller mechanism, where the rotation of the servo motor is decelerated at a substantially constant reduction ratio to cause vibration. Transmits smooth rotation with no work to the work drive shaft (final rotation shaft).
At this time, the rotational position of the workpiece drive shaft is detected by the rotational position detecting means, the detection signal obtained here is sent to the control unit, and the feedback signal obtained by the control unit is sent to the servo motor to perform the servo control. Control the motor.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotation angle indexing actuator of the present invention is applied to a rotation angle indexing spindle of a machine tool as an embodiment shown in FIG. 1. The servo motor 1 is shown in FIG. It is attached to the housing 27 of the speed change planetary friction roller mechanism via the connection housing 18.

The connecting housing 18 has a working window 1
8a is provided, the fixed shaft joint 17 is inserted into the connection housing 18 through the working window 27a, and the fixed shaft joint 17 is tightened to rotate the rotary shaft of the servomotor 1 and the planetary friction roller mechanism for deceleration. Sun roller shaft (input shaft)
10 and 10 are detachably connected. The output shaft of the servomotor 1 may be used as it is as the sun roller shaft (input shaft) 10 of the planetary friction roller mechanism for speed reduction, and the flange portion of the servomotor 1 may be attached to the speed reducer housing 27.

A deceleration planetary friction roller mechanism is provided inside the speed reducer housing 27. This deceleration planetary friction roller mechanism is substantially the same as that described with reference to FIG. 1, the same reference numerals as those in FIG. 4 are used. That is, in the decelerating planetary friction roller mechanism, the sun roller shaft (input shaft) 10 and the sun roller 5 attached thereto rotate, and the three planet rollers 6 arranged at equal pitches have the fixed side elastic ring 7. It is sandwiched between the sun roller 5 and the sun roller 5, and revolves due to frictional force, and the deceleration output shaft 25 rotates via the planetary roller shaft 8.

In this example, the deceleration planetary friction roller mechanism has one stage of deceleration, but the deceleration output shaft 25 remains unchanged.
It is possible to reduce the speed to two stages as the input sun roller of the next speed changing planetary friction roller mechanism, or to reduce the speed to three stages in the same manner. In this case, the actuator can be greatly reduced in speed, A high torque function can be added. A spindle shaft unit (work drive shaft unit) 28 is fitted in the speed reducer housing 27. The spindle shaft unit 28 includes a bearing housing 30 attached to the speed reducer housing 27 and a spindle shaft (work drive shaft) 29.
The spindle shaft 29 is rotatably supported in the bearing housing 30 via a plurality of bearings.

Reference numeral 19 is a rotation position detector (rotary encoder), and the rotation side of the rotation detector 19 is a spindle shaft 29.
And the fixed side of the rotation detector 19 is mounted on the bearing housing 30.
Installed on. The center axis of the spindle shaft 29 and the center axis of the speed reducer output shaft 25 coincide with each other, and the tip end of the spindle shaft 29 is fitted into the shaft hole of the speed reduction output shaft 25 to form two taper expansion ring types. Fixed shaft joint 26
As a result, the spindle shaft 29 is directly connected to the deceleration output shaft 25.

The work window 2 is attached to the speed reducer housing 27.
7a is provided, the tapered expansion ring type fixed shaft joint 26 is put into the reduction gear housing 27 through the work window 27a, and the tapered expansion ring type fixed shaft joint 26 is detachably fixed to the spindle shaft 29. Work drive shaft 2
9 is directly connected to the deceleration output shaft 25. FIG. 2 shows a state in which a center shaft unit (work drive shaft unit) 34 is attached to the rotation angle indexing actuator.

The center shaft unit 34 includes a spindle shaft tube 35 fitted in the speed reducer housing 27, an intermediate tube 36 rotatably supported by the spindle shaft tube 35 via a plurality of bearings, and an intermediate tube. Flange cylinder 38 on cylinder 36
And a center shaft 37 that is fitted through the rotary position detector (rotary encoder) 19 is attached to the intermediate cylinder 36, and the fixed side of the rotation detector 19 is attached to the spindle shaft cylinder 35. There is.

The end of the intermediate cylinder 36 is directly connected to the deceleration output shaft 25 via a tapered expansion ring type fixed shaft joint 26. Next, the operation of the rotation angle indexing actuator will be specifically described. The fixed shaft joints 17 and 26 connect the output shaft of the servomotor 1 and the input shaft 10 of the decelerating planetary friction roller mechanism, and the output shaft 25 of the decelerating planetary friction roller mechanism and the spindle shaft 29.

In the connection by the fixed shaft joints 17 and 26, there is no play in the shaft connecting portion and the slippage of the decelerating planetary friction roller mechanism is slight, which is a problem.
The rotation of the servomotor 1 is reduced at a substantially constant reduction ratio, and smooth rotation without vibration is transmitted to the spindle shaft 29 (final rotation axis). At this time, the rotational position of the spindle shaft 29 is detected by the rotational position detector (rotary encoder) 19, the detection signal obtained here is sent to the control unit, and a feedback signal from the control unit is sent to the servo motor 1. , The same servo motor 1 is controlled, so the spindle shaft 2
A highly accurate indexing angle can be obtained with 9.

Further, the servo motor 1 and the speed reducer housing 2
7 and spindle shaft unit (work drive shaft unit) 2
8 is integrated, the overall length of the actuator can be shortened and the rigidity can be increased. Therefore, it is possible to easily perform a layout design when applied to a parent machine, for example, a gear cutting machine, a tooth grinding machine, a copying milling machine, or the like. Further, after operating the taper expansion ring type fixed shaft joint 26 from the work window 27a of the reduction gear housing 27 and loosening it so that the spindle shaft 29 or the intermediate cylinder 36 can be pulled out, the spindle shaft unit (work drive shaft unit). ) 2
8 or the center shaft unit (work drive shaft unit) 34 is pulled out from the reducer housing 27.
The work drive shaft unit can be easily replaced. At that time, the rotary position detector (rotary encoder) 1
9 can be taken out while being attached to the spindle shaft unit 28 or the center shaft unit 34.

[0028]

As described above, in the rotary angle indexing actuator of the present invention, since the servo motor, the speed reducer housing and the work drive shaft unit are integrated, the total length of the actuator can be shortened and the actuator can be housed within a desired size. In addition, the rigidity can be increased, and the layout design can be easily performed when it is applied to a parent machine such as a gear cutting machine, a tooth grinder, or a copy milling machine.

Further, since the output shaft of the decelerating planetary friction roller mechanism and the work drive shaft are connected by the fixed shaft joint, there is no play in the shaft connecting portion, and the slipping of the decelerating planetary friction roller mechanism is slight. In addition, the rotation of the servo motor is reduced at a substantially constant reduction ratio, and smooth rotation without vibration is transmitted to the work drive shaft (final rotation shaft). At this time, the rotational position of the work drive shaft is accurately detected by the rotational position detection means, the detection signal obtained here is sent to the control unit, and the feedback signal obtained by the control unit is sent to the servo motor, Since the servo motor is controlled, a highly accurate indexing angle can be obtained on the work drive shaft.

Further, after the fixed shaft joint is operated from the work window of the reducer housing and loosened to allow the work drive shaft to be extracted, the work drive shaft unit is extracted from the reducer housing. It can be easily replaced.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of a rotation angle indexing actuator according to the present invention.

FIG. 2 is a vertical cross-sectional side view showing a state in which another work drive shaft unit is attached to the rotation angle indexing actuator.

FIG. 3 is a perspective view showing a gear reducer of a conventional servo mechanism.

FIG. 4 is a partially cutaway perspective view showing a deceleration friction roller mechanism of the servo mechanism.

FIG. 5 is a partially cutaway perspective view of a deceleration friction roller mechanism and a motor of the servo mechanism.

FIG. 6 is a side view showing another example of a conventional rotation angle indexing actuator.

[Explanation of symbols]

1 servo motor 5 sun roller of deceleration planetary friction roller mechanism 6 planetary roller of deceleration planetary friction roller mechanism 10 sun roller shaft of deceleration planetary friction roller mechanism 19 rotational position detecting means (rotary encoder) 25 deceleration output shaft 26 shaft joint 27 Housing 27a Work Window 28 Spindle Shaft Unit (Work Drive Shaft Unit) 34 Center Shaft Unit (Work Drive Shaft Unit)

Claims (1)

[Claims] 1. A rotation angle indexing actuator having a servomotor, a decelerating planetary friction roller mechanism, and an output shaft rotational position detecting means, wherein an output shaft of the servomotor is a sun roller of the decelerating planetary friction roller mechanism. Mounted on the shaft, the work drive shaft unit is removably mounted on the housing of the planetary friction roller mechanism for deceleration, and the work drive shaft is rotatably mounted on the work drive shaft unit through a plurality of bearings. And the output shaft of the deceleration planetary friction roller mechanism are detachably attached via a fixed shaft joint, and a work window for attachment / detachment of the fixed shaft joint is provided in the housing of the deceleration planetary friction roller mechanism, and the rotational position detecting means is provided. Is attached to the workpiece drive shaft unit.