JP3650606B2 - Electromagnetic clutch - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an electromagnetic clutch that is used in series with a motor that can be used for applications such as a spring return valve, a spring return damper, and a spring return shutter that move forward when the power is turned on and return when the power is turned off. Further, the present invention relates to an electromagnetic clutch that can be used for various emergency shut-off applications, applications that require ON / OFF of motor output torque, and applications that require ON / OFF of motor detent torque (non-excitation holding torque).
[0002]
[Prior art]
As an example of the prior art, a second embodiment of “JP-A-5-244748” will be described with reference to FIG.
[0003]
FIG. 9 is a sectional view in which an electromagnetic clutch according to a conventional example is applied to a motor.
[0004]
The rotating shaft (shaft) 1 becomes free in some cases due to energization ON / OFF of the electromagnetic clutch 5, and is connected to the rotor 8 in some cases to generate output torque. The front bearing 2 and the rear bearing 7 support the shaft 1.
[0005]
The front bearing 2 is fixed to the front flange 3, and the rear bearing 7 is fixed to the rear flange 6.
[0006]
The stator (stator) 4 and the rotor 8 constitute an electromagnetic motor, and the stator 4 is provided with coils 16 and 17 to generate a rotating magnetic field or a moving magnetic field and rotate the rotor 8 through the rotating gap 13. To drive.
[0007]
A rotor (core) 8 that rotates by acting on a rotating magnetic field or a moving magnetic field of the stator 4 is fixed to the rotor spacer 9, and an inner diameter portion of the rotor spacer 9 can move in the axial direction with a gap 14. It is fitted. A first clutch piece 10 is fixed to the rotor spacer 9.
[0008]
A second clutch piece 11 coupled to and separated from the first clutch piece 10 is press-fitted and fixed to the shaft 1. A return spring 12 is arranged between the first clutch piece 10 and the second clutch piece 11.
[0009]
Further, the electromagnetic clutch 20 for operating the coupling / separation of the first clutch piece 10 and the second clutch piece 11 is provided in the electromagnetic clutch 5.
[0010]
Reference numeral 13 denotes a rotation gap between the stator 4 and the rotor 8. Reference numeral 15 denotes a clutch gap when the first and second clutch pieces are separated from each other. A part of FIG. 9 is a motor part equivalent to a capacitor-type synchronous motor “PTM-24M manufactured by Nippon Pulse Motor Co., Ltd.” having a motor outer diameter φ35 (mm). The rotor 8 is an NS24 pole ferrite rotor having an outer diameter of φ16 (mm). Taking this motor for AC 100V as an example, the output torque is 50/60 (HZ) and 120/125 (g-cm). The non-excitation detent torque (holding torque) of this motor is 25 (g-cm) and appears on the shaft 1 only when the electromagnetic clutch 5 is turned on. The shaft free torque when the motor coil energization is OFF and the electromagnetic clutch coil energization is OFF is only the friction torque of the shaft 1 and is about 3 (g-cm).
[0011]
The stator and tooth pole structure of the synchronous motor are conventionally known.
[0012]
The inner diameter portion of the stator of the electromagnetic clutch 5 is a pair of rings having an L-shaped cross section as shown in FIG. 9, and the right magnetic pole of the stator of the electromagnetic clutch 5 is wrapped with the second clutch piece 11 on the magnetic circuit. Although the edges are matched, the first clutch piece 10 is arranged with the edge shifted by a dimension C to the left with respect to the stator left magnetic pole of the electromagnetic clutch 5. With such a structure, when the coil 20 of the stator of the electromagnetic clutch 5 is energized, the second clutch piece 11, that is, the integral shaft 1 does not move in the axial direction, and the first clutch piece 10, That is, only the rotor 8 moves to the right in the axial direction, and the rotor 8 and the shaft 1 are connected. Thus, only the rotor moves within the motor, and the movement of the shaft 1 does not appear in terms of the motor appearance.
[0013]
The electromagnetic clutch coil may be energized by either alternating current or direct current.
[0014]
By selecting a combination of energization ON / OFF of the motor coil, forward / reverse rotation ON / OFF, and electromagnetic clutch ON / OFF with such a configuration, the following six functions can be selected and used.
[0015]
(A) When the motor is not energized and the electromagnetic clutch is OFF :
The motor shaft becomes free, and the shaft can be rotated lightly in the forward and reverse directions.
[0016]
(B) When the motor is energized, forward rotation, and electromagnetic clutch OFF :
The motor rotor idles around the shaft and no output torque appears on the shaft. The motor shaft is almost free.
[0017]
(C) In case of motor energization, reverse rotation and electromagnetic clutch OFF :
The motor rotor idles around the shaft and no output torque appears on the shaft. The motor shaft is almost free.
[0018]
(D) When the motor is not energized and the electromagnetic clutch is ON :
The rotor of the motor is coupled to the shaft by an electromagnetic clutch.
[0019]
Detent torque (non-excitation holding torque) appears on the motor shaft, and forward / reverse rotation becomes heavy. It can be used as a brake.
[0020]
(E) Motor energization, forward rotation, electromagnetic clutch ON :
The rotor of the motor rotates in combination with the shaft.
[0021]
The normal rotation torque of the motor appears on the shaft.
[0022]
(F) For motor energization, reverse rotation, and electromagnetic clutch ON :
The rotor of the motor rotates in combination with the shaft.
[0023]
The normal motor reverse torque appears on the shaft.
[0024]
[Problems to be solved by the invention]
The present invention relates to the improvement of "Japanese Patent Laid-Open No. 5-244748", and an object thereof is to reduce the shaft free torque in the state (A).
[0025]
Another object is to provide an electromagnetic clutch that is quiet, operates stably and is efficient.
[0026]
When an example implemented with a larger capacitor type synchronous motor “PTM-24H” having the same structure as the example shown in the prior art is shown, motor generated torque 240 (g-cm), detent torque 60 (g-cm) ), And the maximum shaft free torque was 24 (g-cm). It has been found that if the motor is large, the magnetic force of the magnet is strong and it is difficult to reduce and stabilize the shaft free torque.
[0027]
Further, in the embodiment of the above “PTM-24H”, when the electromagnetic clutch coil is of AC 100V specification and the power source AC 100V is directly connected to the electromagnetic clutch coil, the clutch attracting force is weak and the slip resistance between the clutch pieces is weak. In addition, there is a problem that noise is generated from the clutch when energized.
[0028]
[Means for Solving the Problems]
In order to solve the above problems, the electromagnetic clutch according to the first aspect of the present invention is connected to a motor in series and is used inside the set of stator pieces having a substantially U-shaped cross section. A stator having a ring-shaped electromagnetic coil accommodated therein, and an opening is provided in the inner peripheral portion of the stator to form a pair of magnetic poles. The inner diameter portion of the stator has the magnetic pole and a gap interposed therebetween. And a first clutch piece that is disposed opposite to and is fixed to the motor shaft, a second clutch piece that is fixed to an output drive member that is movable in the axial direction, and the electromagnetic coil. A coil spring that separates the suction coupling between the first clutch and the second clutch when energized, and the first and second clutch pieces are radially spaced from each other at equiangular intervals. Approximately the same phosphorus with a plurality of extending grooves Characterized in that it is a ferromagnetic shape.
[0029]
The electromagnetic clutch of the second invention is characterized in that, in the first invention, the motor unit is a pulse motor using a DC power source, and the electromagnetic clutch uses a DC power source of the pulse motor.
[0030]
According to a third aspect of the present invention, there is provided an electromagnetic clutch according to the first aspect, wherein the motor unit is a synchronous motor using an AC power supply, and the electromagnetic clutch applies a voltage rectified from the AC power supply voltage to the electromagnetic coil. It is characterized by being.
[0031]
According to a fourth aspect of the present invention, there is provided the electromagnetic clutch according to any one of the first to third aspects, wherein a stopper for preventing the output drive member from coming off is provided on the clutch stator side.
[0032]
According to a fifth aspect of the electromagnetic clutch of the first to third aspects of the present invention , an output drive member stopper is provided on the shaft side (that is, the rotation shaft side) of the motor unit. .
[0033]
[Action]
There is a first clutch piece fixed to the motor output shaft and a second clutch piece opposite to the first clutch piece. An output drive member such as a pinion gear is fixed to the second clutch piece, and the inner diameter portion of the output drive member is the output shaft. Is mounted so as to be movable.
[0034]
The first and second clutch pieces are not contacted by the spring force of the spring when not energized, and are adsorbed and coupled against the spring force of the spring by the magnetic force generated by energization of the excitation coil of the clutch.
[0035]
For the output drive member, a stopper is provided at an appropriate position so that it does not fall out.
[0036]
According to the research of the present inventor, when alternating current is applied to the coil of the electromagnetic clutch via the full-wave rectification bridge, the voltage waveform after rectification and the current waveform flowing through the coil of the electromagnetic clutch are significantly different. Since the load of the full-wave rectified voltage is an electromagnetic induction coil, a current is connected and a smooth direct current of about 50% can be passed through the coil. It is also possible to eliminate the smoothing capacitor used in normal full wave rectification. By applying the full-wave rectified voltage, it is possible to increase the attractive force of the clutch and reduce the noise.
[0037]
The structure of the clutch is to realize a clutch having a strong coupling force that is difficult to slip by making two opposing clutch pieces into a ring shape, providing a plurality of grooves with the opposing surfaces having the same shape, and creating a magnetic stable point.
[0038]
【Example】
Embodiments of the present invention will be described below with reference to FIGS.
[0039]
(First Example)
FIG. 1 is a cross-sectional view of a first embodiment in which the electromagnetic clutch of the present invention is applied to a motor. In this embodiment, the electromagnetic clutch is divided into a motor portion A in the right portion and a clutch portion B in the left portion.
[0040]
First, the motor part A will be described. The shaft 1 is supported by a front bearing 2 and a rear bearing 7. Further, the front bearing 2 is fixed to the flange 48, and the rear bearing 7 is fixed to the flange 6. The rotor (rotor) spacer 9 is press-fitted and fixed to the shaft 1, and the rotor (rotor core) 8 is adhesively fixed to the rotor spacer 9. The stator 21 that rotates the rotor 8 includes a coil 16 and a coil 17.
[0041]
In the clutch part B, the first clutch piece 10 is press-fitted and fixed to the clutch spacer 29 and the clutch spacer 29 is fixed to the shaft 1. An output drive member 44 such as a pinion gear is press-fitted and fixed to the second clutch piece 11 and is fitted to the shaft 1 so as to be movable in the axial direction. The output drive member 44 abuts against a housing 46 fixed to the flange 3 via a stopper 45 so as not to fall off. When the first clutch piece 10 and the second clutch piece 11 do not energize the ring-shaped electromagnetic coil 34 housed inside the pair of stator pieces 18 having a substantially U-shaped cross section, the return spring 12 It is in a non-contact state separated by the elastic force. By energizing the coil 34 of the electromagnetic clutch 31, a magnetic circuit is generated between the electromagnetic clutch stator 22, the first clutch piece 10, and the second clutch piece 11, and the movable second clutch piece 11 becomes the first clutch piece. As a result, the motor output torque is transmitted to the output drive member 44.
[0042]
When the motor coils 16 and 17 and the coil 34 of the electromagnetic clutch 31 are not energized, the torque applied to the output drive member 44 is a torque that rotates only the output drive member 44. (Hereinafter also referred to as “free torque of the output drive member”).
[0043]
In the conventional example, as shown in FIG. 9, when the shaft is rotated in this state, the return spring 12 reverses the second clutch piece 11 and the rotor spacer 9 holding the rotor 8 and the first clutch piece 10. Pressing in the direction, this becomes a frictional force and torque is generated. In the present invention, as shown in FIG. 1, the motor part A and the clutch part B are mechanically separated, and the return spring 12 is press-fitted and fixed to the shaft 1, and the output drive member 44. As a result, a frictional force is mainly applied between the stopper 45 and the output drive member 44. Compared to the conventional example, the spring's elastic force is weak and the frictional point is mechanically limited, so that the shaft free torque is kept small.
[0044]
FIG. 5 is a perspective view of one embodiment of the shape of the clutch piece of the electromagnetic clutch of the present invention, and shows the shape of the clutch pieces 10 and 11. The shapes of the opposing surfaces of the first clutch piece 10 and the second clutch piece 11 are the same.
[0045]
The material of the clutch pieces 10 and 11 is a ferromagnetic material with little residual magnetism, and a plurality of concave grooves 41 are provided in the ring shape at an angular interval in the radial direction. The groove width is constant and narrower than the fan-shaped portion 40 so that the fan-shaped portions 40 of the opposed clutch pieces 10 and 11 do not fit into one concave groove 41.
[0046]
FIG. 6 is a magnetic circuit diagram of the electromagnetic clutch of the present invention, and shows a magnetic circuit of the clutch portion.
[0047]
If the magnetic circuit is configured as shown in FIG. 6, the magnetic resistance can be reduced, and the second clutch piece 11 can be attracted to the first clutch piece 10 side against the return spring 12 with a small electric power. It becomes.
[0048]
The structure of the electromagnetic clutch will be further described. If the clutch pieces 10 and 11 have the structure shown in FIG. 5 and a magnetic circuit is configured as shown in FIG. 6, the magnetic flux generated by energizing the coil 34 of the electromagnetic clutch 31 flows as shown by the arrows in FIG.
[0049]
This magnetic flux enters from the outer periphery of the second clutch piece 11, passes through the opposing surface of the fan-shaped part 40, and escapes to the outer periphery of the first clutch piece 10. When the fan-shaped portions 40 of the clutch pieces 10 and 11 face each other (FIG. 7A), the magnetic resistance is the lowest and the magnetic flux φ is the maximum. The area of the rotary slide prevention force at this time (braking force) T _B is fan face with T _F shown in FIG. 8, the circumferential suction force per unit area, an average radius of gyration of the product of the clutch pieces 10, 11 . This value is low.
[0050]
On the other hand, by providing the clutch pieces 10 and 11 with the concave groove 41 shown in FIG. 5, it is possible to use the magnetic stable restoring force similar to the operating principle of the variable magnetoresistive pulse motor. In FIG. 7A, this magnetic stable restoring force is zero. Over external torque from the state of FIG. 7 (A), the torque T _M generated by the magnetic stabilizing force shown in FIG. 8 the shifted one of the clutch pieces 10, 11 in the rotational direction. Clutch having four grooves as shown in FIG. 5 with the groove 41 and the groove 41 of the clutch pieces 10 and 11, in other words, the angle at which the fan-shaped portion 40 and the fan-shaped portion 40 are completely opposed to each other is 0 degrees. If pieces 10 and 11, the torque T _B by the magnetic stability restoring force at 45 degrees staggered angle shown in FIG. 7 (B) is maximized.
[0051]
In the example of the clutch piece outer diameter 20 (mm), the brake torque without a groove was 100 (g-cm), and when four grooves were provided, the brake torque could be 350 (g-cm).
[0052]
Next, the electromagnetic clutch power supply will be described.
[0053]
A direct current power source is suitable for this power source. Therefore, if the motor part A of the motor with a built-in electromagnetic clutch is a motor using a DC power source such as a pulse motor, the DC power source can also be used for the electromagnetic clutch. However, when the motor unit A is an AC motor such as a synchronous motor, a suitable DC power source is created based on the AC power source. FIG. 3 shows a circuit diagram of a power supply unit to the coil of the electromagnetic clutch of the present invention. In FIG. 3, the AC power supply common to the motor unit A is rectified by the diode bridge 38 via the operation switch 33 that turns on and off the supply to the electromagnetic clutch, and the rectified voltage is applied to the coil 34 of the electromagnetic clutch 31.
[0054]
According to the study of the present inventor, it has been found that the voltage waveform after rectification by the diode bridge 38 and the current waveform flowing in the coil 34 of the electromagnetic clutch 31 are significantly different from each other in the connection of FIG. FIG. 4A shows a waveform of a current flowing through the coil of the electromagnetic clutch according to the present invention, and FIG. 4B shows a voltage waveform after diode bridging rectification.
[0055]
In FIG. 3, it was found that a smooth direct current of about 50% flows as the coil current because the load of the full-wave rectified voltage is an electromagnetic induction coil. In the present invention, the smoothing capacitor used in normal full-wave rectification can be eliminated.
[0056]
By taking the above measures, it is possible to prevent AC noise and vibration generated from the electromagnetic clutch, and to improve the magnetic attractive force of the clutch.
[0057]
(Second embodiment)
FIG. 2 shows a sectional view of a second embodiment in which the electromagnetic clutch of the present invention is applied to a motor.
[0058]
Basically, the structure of both the electromagnetic clutch and the motor is the same as that of the first embodiment, and the parts given the same numbers have the same structure and function, and thus the description thereof is omitted.
[0059]
In FIG. 2, the output drive member 44 is fitted to the shaft 1 so as to be movable in the axial direction, and a stopper 47 is press-fitted and fixed to the shaft 1 to prevent the output drive member 44 from coming off. Different from the embodiment.
[0060]
【The invention's effect】
As described above, if the electromagnetic clutch is configured, the spring force of the coil spring is weak and the friction point is mechanically limited. Therefore, the free torque of the output drive member can be suppressed to several g-cm. .
[0061]
Further, the output drive member does not fall off the shaft with a simple structure.
[0062]
Further, the first and second clutch pieces of the electromagnetic clutch are substantially the same ring-shaped ferromagnetic bodies in which a plurality of concave grooves extending in the radial direction at equal angular intervals are formed on the opposing surfaces. The attraction force of the electromagnetic clutch can be improved, and the anti-slip force between the clutch pieces can be improved.
[0063]
It is also possible to eliminate the smoothing capacitor used for normal full-wave rectification by applying alternating current to the coil of the electromagnetic clutch via the full-wave rectification bridge. It is possible to increase the force and reduce the noise.
[0064]
In addition, the electromagnetic clutch can effectively use the detent torque of the motor to stop the rotation of the output drive member.
[0065]
Further, the above configuration can provide a low-cost electromagnetic clutch.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a first embodiment in which an electromagnetic clutch of the present invention is applied to a motor.
FIG. 2 is a cross-sectional view of a second embodiment in which the electromagnetic clutch of the present invention is applied to a motor.
FIG. 3 is a circuit diagram of a power supply unit to the coil of the electromagnetic clutch of the present invention.
4A is a waveform of a current flowing through a coil of an electromagnetic clutch of the present invention. FIG. 4B is a voltage waveform after rectification of a diode bridge. FIG. Perspective view.
FIG. 6 is a magnetic circuit diagram of the electromagnetic clutch of the present invention.
FIG. 7 is a cross-sectional view of a state in which a clutch piece of the electromagnetic clutch of the present invention is attracted.
FIG. 8 shows the angle dependency of the rotational slip prevention force in the attracted state of the clutch piece of the electromagnetic clutch of the present invention.
FIG. 9 is a sectional view in which an electromagnetic clutch according to a conventional example is applied to a motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Shaft 2 ... Front bearing 3, 6, 48 ... Flange 4 ... Stator 5, 31 ... Electromagnetic clutch 7 ... Rear bearing 8 ... Rotor 9 ... Rotor spacer 10 ... 1st clutch piece 11 ... 2nd clutch piece 12 ... Return spring 13 ... Gap (rotor-stator)
14 ... Gap (shaft-rotor spacer) 15 ... Gap (between clutch pieces)
16, 17 ... Coil (for motor) 18 ... Stator piece 20, 34 ... Coil (for electromagnetic clutch) 21 ... Stator (for motor)
22 ... Stator (for electromagnetic clutch) 29 ... Clutch spacer 44 ... Output drive member 45, 47 ... Stopper 46 ... Housing

Claims (5)

In an electromagnetic clutch that is connected and used in series with a motor unit , a stator having a ring-shaped electromagnetic coil housed inside a set of stator pieces having a substantially U-shaped cross section;
An opening is provided in the inner peripheral portion of the stator to form a pair of magnetic poles. A first clutch piece fixed to the motor shaft;
A second clutch piece fixed to the output drive member movable in the axial direction;
A coil spring that separates the suction coupling between the first clutch and the second clutch when the electromagnetic coil is energized;
The first and second clutch pieces are ferromagnetic bodies having substantially the same ring shape in which a plurality of concave grooves extending radially at equal angular intervals are formed on opposing surfaces. Electromagnetic clutch.   The electromagnetic clutch according to claim 1, wherein the motor unit is a pulse motor using a DC power source, and the electromagnetic coil of the electromagnetic clutch uses a DC power source of the pulse motor.   The said motor part is a synchronous motor which uses AC power supply, The said electromagnetic clutch applies the voltage rectified from the said AC power supply voltage to the electromagnetic coil, The Claim 1 characterized by the above-mentioned. Electromagnetic clutch.   The electromagnetic clutch according to any one of claims 1 to 3, wherein a stopper for preventing the output drive member from coming off is provided on the clutch stator side.   4. The electromagnetic clutch according to claim 1, wherein a stopper for preventing the output drive member from coming off is provided on the shaft side of the motor unit.

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