JP7618161B2 - Clutch mechanism for servo motor - Google Patents

Description

The present invention relates to a clutch mechanism for a servo motor, and is related to a clutch mechanism for a servo motor that can make the clutch mechanism compact, for example, when two significantly different types of torque are to be extracted from the same output shaft of a single motor.

When high torque is required in a servo motor, a common approach is to combine it with a reducer and sacrifice rotational speed (not being able to rotate at high speed) to obtain torque with double the reduction ratio. However, in the case of mechanisms that use ball screws, such as servo presses, there is an operating pattern in which the motor is rotated at high speed to perform positioning, and then pressure is immediately applied with high torque. However, while mechanisms that use reducers can output high torque, they are unable to output high speed rotations. Conversely, when outputting high speed rotations, it is not possible to output high torque by combining it with a reducer.

In other words, when using a reducer, rotational speed must be sacrificed, making it impossible to achieve both high-speed rotation output and high-torque output. In other words, it was previously impossible to use a reducer to produce two levels of torque, high and low, from a single motor, and from the same output shaft. Therefore, in order to achieve both high-speed rotation output and high-torque output, two types of motors (two motors) with complex mechanisms were used.

As a potential fundamental solution to this problem, a patent application has already been filed for a method that can be used in both low-speed, high-torque and high-speed, low-torque specifications while using a reducer (Patent Document 1, see below). This document discloses a reducer that can be used in both low-speed, high-torque and high-speed, low-torque specifications, including a reduction mechanism having multiple output members that reduce the rotational force of the motor shaft and output a first driving force to an output target, a speed-up mechanism that has a carrier connected to the multiple output members and speeds up the first driving force and outputs a second driving force to a differential case, and a clutch that connects the speed-up mechanism to the differential case and the reduction mechanism to the differential case in an intermittent manner.
Furthermore, Patent Document 2 discloses a clutch mechanism that uses a grooved cam to move two engaging claws and switch the gears to be connected.

JP 2014-052063 A "Reduction gear and motor torque transmission device equipped with the same" Japanese Utility Model Application Publication No. 61-175628 "Clutch switching device"

In the technology disclosed in the above-mentioned document 1, the reducer is configured to include a speed-up mechanism and a speed-down mechanism, and two types of output, low torque at high speed and high torque at low speed, are extracted by a clutch that selectively connects either the speed-up mechanism or the speed-down mechanism to the differential case. In other words, this is a complex configuration and method in which not only a speed-down mechanism but also a speed-up mechanism is provided to make a reducer, and it is not suitable for preventing the overall device in which it is installed from becoming larger, or for simplifying the combination mechanism in the combination of a motor and a reducer. Therefore, there is a demand for a simpler configuration and method that can also contribute to preventing the overall device in which it is installed from becoming larger and simplifying the combination mechanism.

Furthermore, servo motors have traditionally been equipped with non-excitation actuated brakes to allow for emergency stops in the event of a power outage or other such event. However, installing such a non-excitation actuated brake requires space, which is also disadvantageous in preventing the overall size of the device in which it is installed from increasing. If it were possible to obtain two types of output, low torque at high speed and high torque at low speed, from a single motor and a single output shaft, and to eliminate the need for a non-excitation actuated brake, this would be advantageous in preventing the overall size of the device in which it is installed from increasing and simplifying the combined mechanism.

So far, we have discussed the problems and issues involved in obtaining two types of output from a servo motor. Generally, the clutches used in conventional FA control whether a specific operating object is connected or disconnected (neutral), thereby determining whether or not the operating object will produce an output. In other words, one clutch mechanism is required for each operating object that produces an output. If a single servo motor requires clutch intermittent action for multiple operating objects, then the servo motor will inevitably become larger, which does not meet the demand for compactness. There is a demand for a clutch mechanism that does not hinder the compactness of servo motors, and that contributes to compactness.

The problem that this invention aims to solve is to provide a clutch mechanism that can eliminate the problems of the conventional technology and can switch between two different outputs, such as high speed rotation and low torque, and low speed rotation and high torque, from a single servo motor without increasing its size, i.e., can switch outputs.

After studying the above problem, the inventors of the present application found that the problem could be solved by providing separate connecting parts on the ON and OFF sides of the clutch armature, and completed the present invention based on this. In other words, the invention claimed in this application as a means for solving the above problem, or at least the invention disclosed therein, is as follows.

[1] A clutch mechanism for a servo motor, which uses an electromagnetic clutch to switch the output of a servo motor equipped with a paradox planetary gear mechanism having the configuration described in <G> below as a reducer, the clutch mechanism being composed of a clutch armature constituting an electromagnetic clutch, a connecting portion (hereinafter referred to as the "ON-time connecting portion") in an output mechanism (hereinafter referred to as the "ON-time output mechanism") to which the clutch armature is connected when current is applied (hereinafter referred to as the "ON-time"), and a connecting portion (hereinafter referred to as the "OFF-time connecting portion") in an output mechanism (hereinafter referred to as the "OFF-time output mechanism") to which the clutch armature is connected when current is cut off (hereinafter referred to as the "OFF-time"), and which is disposed in the space between the servo motor main body and the reducer, wherein when the clutch armature fixes a first internal gear, a high torque at low speed is output, and when the clutch armature fixes a carrier, a low torque at high speed is output .
<G> The paradox planetary gear mechanism consists of a sun gear that rotates integrally with the motor shaft, planetary gears that revolve around the sun gear while rotating on their own axis, a first internal gear that meshes with the planetary gears and is acted upon by the clutch armature, a second internal gear that meshes with the planetary gears, has a different number of teeth from the first internal gear, and rotates integrally with the output shaft, and a carrier that houses the planetary gears and is acted upon by the clutch armature.
[2] The clutch mechanism for a servo motor according to [1], characterized in that the connecting structure connecting the clutch armature and each of the connecting portions is a meshing structure provided on both of them.
[3] The clutch mechanism for a servo motor according to [1], characterized in that a connecting structure connecting the clutch armature and each of the connecting portions is a friction structure provided on both of them.
[4] The clutch mechanism for a servo motor according to either [2] or [3], characterized in that the connecting structure provided in the clutch armature is different for the ON-time connecting portion and for the OFF-time connecting portion.

[5] A clutch mechanism for a servo motor according to any one of [1], [2], [3], and [4], characterized in that the ON-time output mechanism and the OFF-time output mechanism output their respective outputs from a same output shaft.
[ 6 ] A clutch mechanism for a servo motor according to any one of [1], [2], [3], [4], and [5], characterized in that the first internal gear is an OFF-time connecting portion, and the carrier is an ON-time connecting portion.
[ 7 ] The clutch mechanism for a servo motor according to any one of [1], [2] , [3], [4], [5], and [6], characterized in that the planetary gear is a two-stage planetary gear in which a first planetary gear meshing with the first internal gear and a second planetary gear meshing with the second internal gear are integrally formed.
[ 8 ] A clutch mechanism for a servo motor according to any one of [1], [2], [3], [4], [5], [6], and [7], which is a non-excitation operation type, whereby, in the event of a power outage, the motor shaft is connected to the reducer and is subjected to the deceleration effect.

Since the servomotor clutch mechanism of the present invention is configured as described above, it makes it possible to switch between operating targets that produce different outputs, i.e., output switching, in a single servomotor, without increasing the size of the servomotor, for example, two types of output: high speed rotation, low torque, and low speed rotation, high torque. In other words, two different types of motor output can be obtained from the same output shaft using only one clutch mechanism. Naturally, it can be made more compact than a system with two clutch mechanisms.

The servo motor clutch mechanism of the present invention can, for example, produce two types of output, high speed low torque and low speed high torque, from a single motor and a single output shaft, while preventing the servo motor from becoming too large. In addition, the present invention also realizes an emergency stop mechanism that does not use a non-excitation actuated brake, making it unnecessary to install a non-excitation actuated brake.

As mentioned above, in the past, it was not possible to extract two different torques, with or without a reducer, from a single motor and from the same output shaft, so two different motors with complex mechanisms were prepared. With this invention, it is possible to realize a single motor that can variably use two different torques, with or without a reducer, and furthermore, by eliminating the need for a non-excitation operating brake, it is possible to greatly simplify the system.

The technology disclosed in the above-mentioned Document 1 uses a reducer equipped with a speed-up mechanism and a speed-down mechanism, and two types of output are extracted by a clutch that selectively connects either the speed-up mechanism or the speed-down mechanism to the differential case, which differs from the present invention. Also, the technology disclosed in the above-mentioned Document 2 is a clutch mechanism technology that uses a grooved cam to move two engaging claws and switch the connected gear, which differs from the present invention, which is premised on a clutch mechanism that attracts the armature by energizing a coil.

1 is a conceptual cross-sectional view showing the basic configuration and operation of a clutch mechanism for a servo motor according to the present invention (when energized). FIG. 1 is a conceptual cross-sectional view showing the basic configuration and operation of a clutch mechanism for a servo motor according to the present invention (when current is cut off). 1 is a cross-sectional view illustrating a main portion of an example of a clutch mechanism for a servo motor according to the present invention that has an interlocking structure; 1 is a side sectional view illustrating the configuration and operation of a variable torque motor using a servo motor clutch mechanism according to the present invention (high torque mode). FIG. 1 is a side sectional view illustrating the configuration and operation of a variable torque motor using a servo motor clutch mechanism according to the present invention (high speed rotation mode). FIG.

The present invention will now be described in detail with reference to the drawings.
1 and 1-2 are conceptual cross-sectional views showing the basic configuration and operation of a servo motor clutch mechanism of the present invention (when energized and when de-energized, respectively). As shown in these figures, the servo motor clutch mechanism 100 is a clutch mechanism that switches the output of a servo motor by an electromagnetic clutch, and is mainly composed of a clutch armature 20 constituting an electromagnetic clutch, a coupling portion (ON-time coupling portion) 30 in an output mechanism (ON-time output mechanism) 40 to which the clutch armature 20 is coupled when energized (ON), and a coupling portion (OFF-time coupling portion) 50 in an output mechanism (OFF-time output mechanism) 60 to which the clutch armature 20 is coupled when de-energized (OFF).

In the present servo motor clutch mechanism 100 having such a configuration, when the servo motor is ON, as shown in FIG. 1, the clutch armature 20 is connected to the ON-time connection portion 30, thereby connecting the clutch armature 20 to the ON-time output mechanism 40, and the ON-time output mechanism 40 operates. On the other hand, when the servo motor is OFF, as shown in FIG. 1-2, the clutch armature 20 is connected to the OFF-time connection portion 50, thereby connecting the clutch armature 20 to the OFF-time output mechanism 60, and the OFF-time output mechanism 60 operates. In this way, according to the present invention clutch mechanism 100, the electromagnetic clutch is switched between ON and OFF, and the output mechanism is switched, rather than switching ON/OFF of a specified output as in the conventional case. In other words, the output of the servo motor is switched between the ON-time output mechanism 40 and the OFF-time output mechanism 60.

Figure 2 is a cross-sectional view of the main part of an example of a servo motor clutch mechanism of the present invention having an interlocking structure. As shown in the figure, this servo motor clutch mechanism can have an interlocking structure in which the clutch armature 25 and each of the connecting parts, i.e., the ON-time connecting part 35 and the OFF-time connecting part 55, have a connecting structure that connects them. In other words, the connecting part of the clutch armature 25 with the ON-time connecting part 35 can be configured to interlock with the ON-time connecting part 35, while the connecting part with the OFF-time connecting part 55 can be configured to interlock with the OFF-time connecting part 55.

As shown in the figure, therefore, the coupling structure of the clutch armature 25 may be different for the ON-time coupling portion 35 and the OFF-time coupling portion 55. For example, the clutch armature 25 may be configured with a meshing structure on each side that is suitable for the output mechanism to be coupled, such as a high-torque output mechanism or an output mechanism in which smooth coupling is important.

In the illustrated example, (a) shows the action of the clutch armature 25 when ON, and (b) shows the action when OFF. When ON, the clutch armature 25 meshes with and connects to the ON-time connecting portion 35, thereby connecting to the ON-time output mechanism (not shown), which activates the ON-time output mechanism. When OFF, on the other hand, the clutch armature 25 meshes with and connects to the OFF-time connecting portion 55, thereby connecting to the OFF-time output mechanism (not shown), which activates the OFF-time output mechanism.

In addition, in the servo motor clutch mechanism of the present invention, the connection structure that connects the clutch armature to each connection part may be a friction structure that both have. Also, the ON-time output mechanism and the OFF-time output mechanism may be configured to output their respective outputs from the same output shaft. As such an example, a variable torque motor that uses this servo motor clutch mechanism will be described.

Figures 3 and 4 are explanatory side sectional views showing the configuration and operation of a variable torque motor using the servo motor clutch mechanism of the present invention, with Figure 1 showing the high torque mode and Figure 2 showing the high speed rotation mode. As shown in these figures, the servo motor clutch mechanism 10 in this variable torque motor 10 is a clutch mechanism 1 provided between a motor body 9 and a reducer 2 in a servo motor equipped with a paradox planetary gear mechanism 2 having the configuration described in <G> below as a reducer.
<G> A paradox planetary gear mechanism 2 consisting of a sun gear 3 that rotates integrally with the motor shaft 8, a planetary gear 4 that revolves around the sun gear 3 while rotating on its axis, a first internal gear 6 that meshes with the planetary gear 4 and is acted upon by the clutch armature 1w, a second internal gear 5 that meshes with the planetary gear 4, has a different number of teeth from the first internal gear , and rotates integrally with the output shaft, and a carrier 7 that houses the planetary gear 4 and is acted upon by the clutch armature 1w.

When the clutch armature 1w (a clutch action portion that performs the transmission and disconnection action to the clutch action target) fixes the first internal gear 6 , a low-speed rotation high torque is output, and when the carrier 7 is fixed, a high-speed rotation low torque is output. In other words, this variable torque motor 10 can extract two types of torque from the same output shaft by the servo motor clutch mechanism 1 and the reducer 2 that is the target of the clutch action performed by this.

In the variable torque motor 10 having such a configuration, when the clutch armature 1w of the servo motor clutch mechanism 1 moves toward and connects with the first internal gear 6 as shown in Fig. 3, thereby fixing the first internal gear 6 and stopping the state, the carrier 7 accommodating the planetary gears 4 is released, and therefore the planetary gears 4 meshing with the first internal gear 6 revolve around the sun gear 3 which rotates in synchronization with the motor shaft 8 while rotating on their own axis. The rotation of the planetary gears 4 is transmitted to the second internal gear 5 which has a different number of teeth from the first internal gear 6 , and is output to the output shaft 11 which rotates integrally therewith. In other words, the rotation of the motor shaft 8 is decelerated by the effective deceleration action of the paradox planetary gear mechanism 2, and as a result, a low-speed rotation, high-torque output is output to the output shaft 11.

On the other hand, as shown in FIG. 4, when the clutch armature 1w of the servo motor clutch mechanism 1 moves toward the carrier 7 and connects thereto, thereby fixing the carrier 7, the first internal gear 6 meshing with the planetary gear 4 is released, and therefore the planetary gear 4 meshing with the first internal gear 6 rotates on the spot in accordance with the sun gear 3 rotating synchronously with the motor shaft 8, since the carrier 7 is fixed. The rotation of the planetary gear 4 is transmitted to the second internal gear 5 and output to the output shaft 11 rotating integrally therewith. That is, the rotation of the motor shaft 8 is not decelerated by the paradox planetary gear mechanism 2, but is output to the output shaft 11 rotating integrally therewith as a simple planetary gear mechanism. That is, the rotation of the motor shaft 8 is transmitted without being subjected to an effective deceleration action by the paradox planetary gear mechanism 2, and as a result, a high-speed rotation, low-torque output is output to the output shaft 11. The output shaft 11 rotates at high speed together with the motor shaft 8.

In this manner, in the present variable torque motor 10, by selecting the operation of the servo motor clutch mechanism 1, i.e., whether to operate so as to fix the first internal gear 6 or to operate so as to fix the carrier 7, it is possible to obtain rotational output in a low-speed rotation, high-torque mode in the former case, and in a high-speed rotation, low-torque mode in the latter case. In other words, the reducer 2 can produce two types of torque from the same output shaft. Therefore, when a high-speed rotation output is required, the motor body 9 is not connected to the paradox planetary gear mechanism 2, and the low reduction ratio output of the motor body 9 is utilized as a simple planetary gear mechanism, while when a high torque output is required, the motor body 9 is connected to the paradox planetary gear mechanism 2 to obtain torque with a high reduction ratio.

As shown in each figure, the servomotor clutch mechanism 1 of the variable torque motor 10 can be configured such that its clutch armature 1w fixes the first internal gear 6 by releasing and the carrier 7 by attracting. That is, the first internal gear 6 is the OFF-time connected portion, and the carrier 7 is the ON-time connected portion. As a result, when the servomotor clutch mechanism 1 is released, the first internal gear 6 is fixed (the carrier 7 is released) and the reducer 2 operates effectively, and the above-mentioned operation is performed in the low-speed rotation, high-torque mode, while when the servomotor clutch mechanism 1 is attracted, the carrier 7 is fixed ( the first internal gear 6 is released) and the deceleration action of the reducer 2 is disabled, and the above-mentioned operation is performed in the high-speed rotation, low-torque mode. Note that the case where the release-attraction and fixed target patterns of the servomotor clutch mechanism 1 are reversed is also within the scope of the present invention.

The planetary gear 4 of the paradox planetary gear mechanism 2, which is the reducer of the variable torque motor 10, is a two-stage planetary gear in which a first planetary gear meshing with the second internal gear 5 and a second planetary gear meshing with the first internal gear 6 are integrally constructed. In other words, the sun gear 3 rotates the second planetary gear 4b, and the first planetary gear 4a, which is an integral part of the second planetary gear 4b, rotates in response to the rotation, and the second internal gear 5 rotates.

In addition, the servo motor clutch mechanism 1 of the variable torque motor 10 of the present invention can be of the non-excitation operation type. Conventionally, a non-excitation operation type brake is generally used to respond to an emergency stop during high-speed rotation due to a power outage or the like. However, by making the electromagnetic clutch 1 of the variable torque motor 10 of the present invention of the non-excitation operation type, the servo motor clutch mechanism 1 is released during a power outage, and the clutch armature 1w comes into contact with and fixes the first internal gear 6 , and the motor shaft 8 of the motor body 9 is connected to the reduction gear 2. In other words, the rotation of the motor shaft 8 is subjected to a deceleration action by the reduction gear 2, and it is possible to stop the rotation of the motor shaft 8 by utilizing the motor cogging torque. The stopping torque of the output shaft 11 is a reduction ratio multiplied by the motor cogging torque.

Therefore, the variable torque motor 10 can be stopped in an emergency without using a non-excitation actuated brake, and the absence of a non-excitation actuated brake can be added as a feature in addition to any of the above configurations. If the clutch is of the non-excitation actuated type, an operation method is also possible in which the clutch is attracted during a power outage to release the first internal gear 6 and disable the reduction mechanism. In this case, the stopping torque of the output shaft 11 is only the motor cogging torque.

The servo motor clutch mechanism of the present invention makes it possible to switch between two different outputs, such as high speed rotation and low torque, and low speed rotation and high torque, in a single servo motor without increasing the size of the servo motor. Therefore, this invention has high industrial applicability in the fields of motor manufacturing and use, including industrial motors, and in all related fields.

1...Servo motor clutch mechanism 1w...Clutch armature (clutch action portion)
2...Reduction gear (paradoxical planetary gear mechanism)
3...Sun gear 4...Planetary gear (two-stage planetary gear)
5...Second internal gear
6...First internal gear
7...Carrier 8...Motor shaft 9...Motor body 10...Variable torque motor 11...Output shaft 12...Torque variable structure 20, 25...Clutch armature 30, 35...ON-time connecting portion 40...ON-time output mechanism 50, 55...OFF-time connecting portion 60...OFF-time output mechanism 70...Coil 80...Motor shaft 100...Servo motor clutch mechanism Rs...Resolver (rotation detector)

Claims (8)

A clutch mechanism for switching the output of a servomotor having a paradox planetary gear mechanism having the configuration described in <G> below as a reducer, using an electromagnetic clutch,
The clutch mechanism includes:
A clutch armature that constitutes an electromagnetic clutch;
a coupling portion (hereinafter referred to as an "ON-time coupling portion") in an output mechanism (hereinafter referred to as an "ON-time output mechanism") to which the clutch armature is coupled when electricity is applied (hereinafter referred to as an "ON-time"); and
and a coupling portion (hereinafter referred to as the "OFF-time coupling portion") in an output mechanism (hereinafter referred to as the "OFF-time output mechanism") to which the clutch armature is coupled when the current is cut off (hereinafter referred to as the "OFF-time").
The servo motor is disposed in a space between the servo motor body and the reducer.
When the clutch armature fixes the first internal gear, a low speed rotation and a high torque are output, and when the clutch armature fixes the carrier, a high speed rotation and a low torque are output.
A clutch mechanism for a servo motor, comprising:
<G> The paradoxical planetary gear mechanism is a sun gear that rotates together with the motor shaft,
a planetary gear that revolves around the sun gear while rotating on its axis;
a first internal gear meshing with the planetary gear and acted upon by the clutch armature;
a second internal gear which meshes with the planetary gear, has a number of teeth different from that of the first internal gear, and rotates integrally with the output shaft;
and a carrier which houses the planetary gear and is acted upon by the clutch armature. The clutch mechanism for a servo motor according to claim 1, characterized in that the connecting structure connecting the clutch armature and each of the connecting parts is a meshing structure provided on both of them. The clutch mechanism for a servo motor according to claim 1, characterized in that the connecting structure connecting the clutch armature to each of the connecting parts is a friction structure provided on both of them. The clutch mechanism for a servo motor according to claim 2 or 3, characterized in that the coupling structure of the clutch armature is different for the ON-time coupling portion and the OFF-time coupling portion. A clutch mechanism for a servo motor according to any one of claims 1, 2, 3, and 4, characterized in that the ON-time output mechanism and the OFF-time output mechanism output their respective outputs from the same output shaft. 6. A clutch mechanism for a servo motor according to claim 1 , wherein the first internal gear is an OFF-time connecting portion, and the carrier is an ON-time connecting portion. The clutch mechanism for a servo motor according to any one of claims 1, 2, 3, 4, 5 and 6, characterized in that the planetary gear is a two-stage planetary gear in which a first planetary gear meshing with the first internal gear and a second planetary gear meshing with the second internal gear are integrally formed. 8. A servo motor clutch mechanism according to claim 1, 2, 3, 4, 5 , 6 or 7, which is of a non-excitation operation type, whereby , in the event of a power failure, the motor shaft is connected to the reducer and is subjected to the deceleration effect thereof .