JP2008286333A - Electromagnetic brake apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a brake start time on braking in an emergency by starting braking without waiting for sufficient reduction of a current of a brake electromagnet. <P>SOLUTION: An electromagnetic brake device is provided with the brake electromagnet 5, arranged for the fixed iron-core 1, consisting of a fixed iron-core 1 which is fixed, a movable iron-core 2 movably arranged for the fixed iron core 1, a coil 3 for generating a magnetic flux for the fixed iron-core 1 and the movable iron-core 2 and a spring 4 for providing a reaction force to the movable iron core 2 and brakes a movement of an object to be braked by a force of the brake electromagnet 5 and includes a piezoelectric element 21 as an action assist means having time response quicker than the brake electromagnet 5. The piezoelectric element 21 is provided in the fixed iron-core 1 and lifts up the movable iron-core 2 when receiving a braking instruction so as to form a small clearance between the fixed iron-core 1 and the movable iron-core 2 of the brake electromagnet 5. Thus, the electromagnet force of the brake electromagnet 5 becomes smaller than a spring force of the spring 4 and it is possible to start the braking action without waiting for sufficient reduction of the current of the coil 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic brake device, and more particularly to an electromagnetic brake device that operates with an electromagnet and a spring.

  In a conventional electromagnetic brake device, during an emergency operation, the current that is electromagnetically attracted against the spring force is commutated to the discharge circuit by opening the contact of the electric circuit, and the current is reduced to release the brake. Thus, braking force is obtained (see, for example, Patent Document 1).

JP 2003-081543 A

  However, in the conventional electromagnetic brake device, before braking is applied during an emergency brake operation, the time until an abnormality is detected and a braking command is issued, the time until an electrical circuit contact is opened, the time when the current decreases, and the electromagnet There is a problem that it takes time for the movable part to move and it takes a long time to start braking.

  The present invention has been made to solve such a problem, and an object thereof is to obtain an electromagnetic brake device capable of shortening the time until the start of braking.

  The present invention provides a fixed iron core that is fixed, a movable iron core that is movably provided with respect to the fixed iron core, a coil that generates magnetic flux with respect to the iron core, and a fixed iron core that is provided on the movable iron core. An electromagnetic brake device having a brake electromagnet composed of a spring for applying a reaction force and braking the operation of a braking object with the force of the brake electromagnet, having a faster time response than the brake electromagnet, Operation assisting means for reducing the electromagnetic force of the brake electromagnet before starting the braking operation is provided.

  The present invention provides a fixed iron core that is fixed, a movable iron core that is movably provided with respect to the fixed iron core, a coil that generates magnetic flux with respect to the iron core, and a fixed iron core that is provided on the movable iron core. An electromagnetic brake device having a brake electromagnet composed of a spring for applying a reaction force and braking the operation of a braking object with the force of the brake electromagnet, having a faster time response than the brake electromagnet, Operation assistance means for reducing the electromagnetic force of the brake electromagnet before the start of braking operation is provided, so that braking can be started without waiting for the brake electromagnet current to sufficiently decrease, thus shortening the time to start braking. can do.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing an electromagnetic brake device according to Embodiment 1 of the present invention. In this Embodiment 1, the example utilized for the elevator hoisting machine is given and demonstrated. As shown in FIG. 1, the electromagnetic brake device according to the first embodiment includes a fixed iron core (stator) 1 that is fixedly installed and a movable iron core (mover) 2 that is movably provided with respect to the fixed iron core 1. And a brake electromagnet 5 composed of a coil 3 for generating magnetic flux in those iron cores and a spring 4 provided on the fixed iron core 1 for applying a reaction force to the movable iron core 2. The electromagnetic brake device according to the first embodiment uses the brake electromagnet 5 to brake the movement to be braked. Further, in the electromagnetic brake device according to the first embodiment, the brake pad 10 attached to the movable iron core 2 of the brake electromagnet 5 via the support member 6 and the fixed iron core 1 of the brake electromagnet 5 are embedded. And a piezoelectric element 21 as an operation assisting means. The operation assisting unit operates so as to reduce the electromagnetic force of the brake electromagnet 5 before starting the braking operation of the brake electromagnet 5. In FIG. 1, reference numeral 11 denotes a rotating body provided in the elevator hoisting machine, which is a braking target in the first embodiment.

The configuration of the electromagnetic brake device according to the first embodiment will be described in more detail.
The movable iron core 2 is provided so as to be movable in the vertical direction in the figure with respect to the fixed iron core 1. The movable iron core 2 is stationary on the fixed iron core 1 side in contact with the fixed iron core 1 as shown in FIG. 1 during normal operation of the elevator. However, during emergency braking, it moves upward in the figure and moves away from the fixed iron core 1. Moreover, as described above, the brake pad 10 is attached to the movable iron core 2 on the side opposite to the fixed iron core 1 side. In the example of FIG. 1, the brake pad 10 is supported by the support member 6 and provided on the movable core 2. However, the present invention is not limited to this, and the brake pad 10 may be directly fixed to the movable core 2. In addition, the brake pad 10 is arrange | positioned so that the rotary body 11 of an elevator hoisting machine may be opposed via a predetermined space | gap. During normal operation of the elevator, a predetermined gap is opened as described above. However, during emergency braking, as the movable iron core 2 moves upward in the figure, the brake pad 10 also moves upward in the figure. And pressed against the rotating body 11. As a result, a braking force can be obtained.

  The spring 4 is for applying a reaction force from the fixed iron core 1 to the movable iron core 2, and the coil 3 is for generating magnetic flux in the iron core. The spring 4 and the coil 3 are embedded in the main surface facing the movable iron core 2 of the fixed iron core 1. In the design of the brake electromagnet, the current that generates an electromagnetic force obtained by adding a surplus force to the spring force of the spring 4 is called a design holding current, and the current at which the spring force and the electromagnetic force become equal and the braking operation is started is the design operating current. I call it. During normal operation of the elevator, a design holding current is applied to the coil 3, so that the electromagnetic force is larger than the spring force. Therefore, the movable iron core 2 is not pushed out by the spring 4, but is held in the state shown in FIG. . At the time of emergency braking, the electromagnetic force becomes smaller than the spring force and is pushed out by the spring 4, and the movable iron core 2 moves upward in the drawing, and the braking operation is started. Details of the operation will be described later.

  Further, as described above, in the first embodiment, the braking operation is assisted in the main surface of the fixed iron core 1 facing the movable iron core 2 in order to shorten the time until the brake electromagnet 5 starts the braking. A piezoelectric element 21 is provided as an operation assist means. The piezoelectric element 21 has a faster time response than the brake electromagnet 5 and starts to operate at an earlier time than the brake electromagnet 5 during emergency braking, and widens a gap (gap) between the movable iron core 2 and the fixed iron core 1. Generate power. Thereby, the electromagnetic force of the brake electromagnet 5 is reduced before the braking operation is started. As the piezoelectric element 21, for example, the displacement is as small as several tens of μm, but it is preferable that the piezoelectric element 21 is composed of an element called a piezo element or the like, which has a quick time response and can generate a large force.

Next, the operation of the electromagnetic brake device according to the first embodiment will be described.
As described above, in the electromagnetic brake device according to the first embodiment, the design holding current is applied to the coil 3 of the brake electromagnet 5 during normal operation, so the electromagnetic force of the brake electromagnet 5 is the spring of the spring 4. Since it is larger than the force, the movable iron core 2 is not pushed out by the spring 4, and as shown in FIG. 1, the brake pad 10 and the rotary body 11 of the elevator hoisting machine are separated from each other. Smooth rotational movement is possible.

  On the other hand, during emergency braking, a control device (not shown) provided in the electromagnetic brake device according to the first embodiment issues a first command to reduce the coil current of the coil 3 as an emergency stop command, and piezoelectric A second command for giving a predetermined voltage to the element 21 is issued. The piezoelectric element 21 generates a force larger than the difference between the electromagnetic force and the spring force of the brake electromagnet 5 according to the second command, and creates a gap (gap) of about several tens of μm between the fixed iron core 1 and the movable iron core 2. spread. When the gap is widened, the electromagnetic force of the brake electromagnet 5 is reduced, so that the electromagnetic force becomes smaller than the spring force of the spring 4, and the movable iron core 2 is pushed by the spring 4, and the upward direction in the figure is 0.2 mm to Move about 0.5 mm and start the braking operation. At the start of operation of the piezoelectric element 21, the current of the coil 3 does not decrease so much and remains at the original value. Therefore, the braking force at this time is reduced by reducing the current of the coil 3 to make a gap. Since it is smaller than the case where braking is performed with a spring force, it is possible to prevent sudden braking force generation. After that, according to the first command from the control device, the current of the coil 3 decreases and the braking force increases to a predetermined value.

  In FIG. 2, the horizontal axis represents current, the vertical axis represents electromagnetic force, and the operation when the piezoelectric element 21 is provided (first embodiment) is shown by a solid line, and the operation when the piezoelectric element 21 is not provided (conventional device). The operation is indicated by a broken line. As shown in FIG. 2, it can be seen that when the gap is opened by the piezoelectric element 21, the electromagnetic force is reduced at the same current value as compared with the broken line in which the piezoelectric element 21 is not provided. .

  As described above, in the first embodiment, during emergency braking, the piezoelectric element 21 that operates earlier than the brake electromagnet 5 is configured to open a gap between the fixed iron core 1 and the movable iron core 2, so an emergency stop command At the same time, the gap between the fixed iron core 1 and the movable iron core 2 is opened by the force of the piezoelectric element 21 and the electromagnetic force of the brake electromagnet 5 is reduced. Therefore, the electromagnetic force becomes smaller than the spring force of the spring 4, and the movable iron core 2 is pressed by the spring 4 and comes into contact with the rotor 11 to start a braking operation. That is, braking can be started without waiting for the current of the brake electromagnet 5 to decrease to the design operation current (the spring force and the electromagnetic force become equal to start the braking operation). As a result, the time until the start of braking is short, and sudden braking force generation at the start of braking can be prevented.

  FIG. 3A shows the operation when the piezoelectric element 21 is provided (first embodiment), and FIG. 3B shows the operation when the piezoelectric element 21 is not provided (conventional device). In the case of the first embodiment shown in FIG. 3A, a gap is slightly opened between the fixed iron core 1 and the movable iron core 2 by the force of the piezoelectric element 21 almost simultaneously with the emergency stop command. As described above, when the gap is opened by the force of the piezoelectric element 21, the electromagnetic force of the brake electromagnet 5 is reduced, so that the electromagnetic force becomes smaller than the spring force of the spring 4, and the movable iron core 2 is pushed by the spring 4. Then, it comes into contact with the rotor 11 and the braking operation is started. Therefore, without waiting for the current of the brake electromagnet 5 to decrease to the design operation current (where the spring force and the electromagnetic force are equal and start the braking operation), the current of the brake electromagnet 5 is high as shown in the figure. The movable iron core 2 can be moved. On the other hand, in the conventional case of FIG. 3 (b), an emergency stop is required because it takes time to open the contact of the electric circuit, time to decrease the current, and time to move the spring 4 of the brake electromagnet 5. At the end of a predetermined time after the command is generated, the current value finally reaches the design operating current, and the braking operation is started from that point. Thus, as shown in FIGS. 3A and 3B, in the first embodiment, the time until the start of braking can be shortened.

  When the force of the piezoelectric element 21 is smaller than the difference between the electromagnetic force of the brake electromagnet and the spring force, braking is started while the current of the coil 3 is decreasing. Compared to the case where there is no operation time, it is possible to shorten the operation time until the start of braking.

  As described above, in the present embodiment, during emergency braking, the piezoelectric element 21 that operates earlier than the brake electromagnet 5 is configured to open a gap between the fixed iron core 1 and the movable iron core 2, so an emergency stop command Almost simultaneously, a gap is opened between the fixed iron core 1 and the movable iron core 2 by the force of the piezoelectric element 21, and a braking operation is started. Thereby, the time until the start of braking can be shortened. In addition, when the operation of the piezoelectric element 21 is started, the current of the coil 3 does not decrease so much and remains at the original value. Therefore, the braking force at this time is reduced by reducing the current of the coil 3. Since it is smaller than the case where the brake is applied with spring force, it is possible to prevent a sudden braking force from being generated and to stop the elevator more quietly.

Embodiment 2. FIG.
FIG. 4 is a diagram showing a configuration of an electromagnetic brake device according to Embodiment 2 of the present invention. In the second embodiment, as another method of starting braking early in emergency braking, a configuration in which a small electromagnet 22 smaller than the brake electromagnet 5 is arranged together with the brake electromagnet 5 as shown in FIG. Have. That is, in the second embodiment, the operation assisting unit is the small electromagnet 22. Although the configuration of the small electromagnet 22 is partially omitted for simplification of the drawing, it is the same as the brake electromagnet 5. That is, the small electromagnet 22 has a fixed iron core, a movable iron core, a coil that generates a magnetic flux in the iron core, and a spring that applies a reaction force from the fixed iron core to the movable iron core. In the drawing, only one spring of the small electromagnet 22 is provided. However, the present invention is not limited to this, and a plurality of springs may be provided in the same manner as the brake electromagnet 5. The small electromagnet 22 has such a configuration, and the generated force is set larger than the difference between the electromagnetic force of the brake electromagnet 5 and the spring force of the spring 4. The spring force of the small electromagnet 22 is the force of the brake electromagnet 5. Acts in the direction of widening the gap.

  In the present embodiment, the movable iron core 2 of the brake electromagnet 5 extends in the left-right direction in the drawing as compared to the configuration in FIG. 1 and is longer in the left-right direction in the drawing than the fixed iron core 1. . As shown in FIG. 4, the small electromagnet 22 is provided below the extended portion of the movable iron core 2 of the brake electromagnet 5, and the upper surface of the movable iron core faces the lower surface of the movable iron core 2 of the brake electromagnet 5. , And are arranged via a predetermined gap (about 0.1 to 0.3 mm). In the example of FIG. 4, one pair of small electromagnets 22 is provided on the left and right. Here, it goes without saying that the predetermined gap between the upper surface of the movable iron core of the small electromagnet 22 and the lower surface of the movable iron core 2 of the brake electromagnet 5 is set smaller than the moving distance of the movable iron core of the small electromagnet 22. Yes.

Next, the operation will be described.
In the electromagnetic brake device according to the second embodiment, during normal operation, there is a predetermined gap between the small electromagnet 22 and the movable iron core 2 of the brake electromagnet 5, and the brake electromagnet is not in contact therewith. Since the design holding current is given to the coil 3 of 5, the electromagnetic force of the brake electromagnet 5 is larger than the spring force of the spring 4, so that the movable iron core 2 is not pushed out by the spring 4, as shown in FIG. Since the brake pad 10 and the rotary body 11 of the elevator hoisting machine are separated from each other, the rotary body 11 can perform a smooth rotational motion.

  At the time of emergency braking, a control device (not shown) issues a command to reduce the coil current of the brake electromagnet 5 and the small electromagnet 22, but this reduces the electromagnetic force of the brake electromagnet 5 and the small electromagnet 22. The movable iron core moves upward in the figure by the reaction force of the spring of the small electromagnet 22. Normally, in the small electromagnet 22, since the time until the contact is opened, the time when the current decreases, and the time when the movable core of the electromagnet moves can be made faster than the brake electromagnet 5, the current of the brake electromagnet 5 decreases. Before the operation, the movable iron core of the small electromagnet 22 moves upward in the figure and comes into contact with the lower surface of the movable iron core 2 of the brake electromagnet 5 and lifts upward in the figure, so that the gap of the brake electromagnet 5 can be opened. It is.

  As described above, since the gap is formed between the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5 by the small electromagnet 22 that operates faster than the brake electromagnet 5 at the time of emergency braking, the emergency stop command is slightly delayed. In a certain amount of time, the space between the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5 is opened by the force of the small electromagnet 22 and the electromagnetic force of the brake electromagnet 5 is reduced. The movable iron core 2 is pressed by the spring 4 and comes into contact with the rotor 11 to start a braking operation. That is, braking can be started without waiting for the current of the brake electromagnet 5 to decrease to the design operation current (the spring force and the electromagnetic force become equal to start the braking operation). As a result, the time until the start of braking is short, and sudden braking force generation at the start of braking can be prevented.

  As described above, in the present embodiment, at the time of emergency braking, the small electromagnet 22 that operates faster than the brake electromagnet 5 is configured to open a gap between the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5. Therefore, in a time slightly delayed from the emergency stop command, a gap is opened between the fixed iron core 1 and the movable iron core 2 by the force of the small electromagnet 22 and the braking operation is started. Thereby, the time until the start of braking can be shortened. Further, at the start of operation of the small electromagnet 22, the current of the coil 3 does not decrease so much and remains at the original value. Therefore, the braking force at this time is reduced by reducing the current of the coil 3. Since it is smaller than the case where the brake is applied with spring force, it is possible to prevent a sudden braking force from being generated and to stop the elevator more quietly.

  In the second embodiment, the small electromagnet 22 has the same configuration as that of the brake electromagnet 5, but the small electromagnet 22 may be a latch type electromagnet using a permanent magnet.

Embodiment 3 FIG.
In FIG. 4, the air gap of the brake electromagnet 5 is opened by the spring force of the small electromagnet 22. However, as shown in FIG. 5, the movable iron core of the small electromagnet 22 is used as the magnetic flux between the fixed core 1 and the movable iron core 2 of the brake electromagnet 5. It is good also as arrangement | positioning which bypasses. In this case, the magnetic flux of the brake electromagnet 5 is bypassed to the movable iron core of the small electromagnet 22 so that the electromagnetic force of the brake electromagnet 5 is reduced and the brake electromagnet 5 is opened before the current of the coil 3 is reduced. Start.

  In the present embodiment, the configuration of the brake electromagnet 5 itself is the same as the configuration shown in FIG. On the other hand, as shown in FIG. 5, the small electromagnet 22 is arranged in the lateral direction of the brake electromagnet 5 with the movable iron core facing the brake electromagnet 5. During normal operation, the movable iron core of the small electromagnet 22 is opposed to each of the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5 via a predetermined gap, and during emergency braking, the fixed iron core of the brake electromagnet 5 is fixed. 1 and the movable iron core 2 are both in contact with each other, thereby providing a bypass between the iron cores. In the example of FIG. 5, one pair of small electromagnets 22 is provided on the left and right sides of the brake electromagnet 5. Here, it goes without saying that the predetermined gap between the upper surface of the movable iron core of the small electromagnet 22 and the brake electromagnet 5 is set smaller than the moving distance of the movable iron core of the small electromagnet 22.

Next, the operation will be described.
In the electromagnetic brake device according to the third embodiment, during normal operation, there is a predetermined gap between the small electromagnet 22 and the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5, and is not in contact with each other. Further, since the design holding current is given to the coil 3 of the brake electromagnet 5, the electromagnetic force of the brake electromagnet 5 is larger than the spring force of the spring 4, so that the movable iron core 2 is not pushed out by the spring 4, and is shown in FIG. Like the state, since the brake pad 10 and the rotary body 11 of the elevator hoisting machine are separated from each other, the rotary body 11 can perform a smooth rotational motion.

  At the time of emergency braking, a control device (not shown) issues a command to reduce the coil current of the brake electromagnet 5 and the small electromagnet 22, but this reduces the electromagnetic force of the brake electromagnet 5 and the small electromagnet 22. And each movable iron core moves to the direction away from each fixed iron core by the reaction force of the spring of the small electromagnet 22. Normally, in the small electromagnet 22, since the time until the contact is opened, the time when the current decreases, and the time when the movable core of the electromagnet moves can be made faster than the brake electromagnet 5, the current of the brake electromagnet 5 decreases. Before the operation, the movable iron core of the small electromagnet 22 moves in the direction of the brake electromagnet 5 and comes into contact with the lateral surfaces of the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5. Thus, the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5 are bypassed by the movable iron core of the small electromagnet 22, so that the magnetic flux of the brake electromagnet 5 is bypassed to the movable iron core of the small electromagnet 22 and the electromagnetic force of the brake electromagnet 5 is reduced. Before the current of the coil 3 decreases, the gap of the brake electromagnet 5 opens and braking is started.

  In this way, during emergency braking, the small electromagnet 22 that operates earlier than the brake electromagnet 5 bypasses the space between the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5, and the magnetic flux of the brake electromagnet 5 is reduced to that of the small electromagnet 22. Since the movable iron core is bypassed, the electromagnetic force of the brake electromagnet 5 is reduced by the action of the small electromagnet 22 in a time slightly delayed from the emergency stop command, so that the electromagnetic force is smaller than the spring force of the spring 4. Thus, the movable iron core 2 is pushed by the spring 4 and comes into contact with the rotor 11, and the braking operation is started. That is, braking can be started without waiting for the current of the brake electromagnet 5 to decrease to the design operation current (the spring force and the electromagnetic force become equal to start the braking operation). As a result, the time until the start of braking is short, and sudden braking force generation at the start of braking can be prevented.

  As described above, in the present embodiment, at the time of emergency braking, the small electromagnet 22 that operates faster than the brake electromagnet 5 is configured to bypass between the fixed iron core 1 and the movable iron core 2 of the brake electromagnet 5. In a time slightly delayed from the emergency stop command, the electromagnetic force of the brake electromagnet 5 is reduced by the action of the small electromagnet 22 and the braking operation is started. Thereby, the time until the start of braking can be shortened. Further, at the start of operation of the small electromagnet 22, the current of the coil 3 does not decrease so much and remains at the original value. Therefore, the braking force at this time is reduced by reducing the current of the coil 3. Since it is smaller than the case where the brake is applied with spring force, it is possible to prevent a sudden braking force from being generated and to stop the elevator more quietly.

Embodiment 4 FIG.
The design holding current and the design operating current of the coil 3 that determines the electromagnetic force of the brake electromagnet 5 are not limited to the electromagnetic force margin that does not malfunction due to the spring force of the spring 4 and vibrations such as earthquakes, as well as electromagnetic variations such as manufacturing variations of the brake electromagnet and secular change. Set a larger value in anticipation of the force drop. In the above-described first to third embodiments, an example in which control is performed to reduce the value of the current flowing through the coil 3 based on a preset reduction amount during emergency braking has been described. However, in the present embodiment, An example will be described in which the current flowing through the coil 3 is variable depending on past operating conditions. FIG. 6 is a diagram showing the configuration of the drive circuit of the electromagnetic brake 5. In the drive circuit, as shown in FIG. 6, in addition to the coil 3, the power supply 30, the switch 31, the diode 32, and the discharge resistor 33, which is a brake power supply circuit, the time and current of the brake operation are detected during normal brake operation. And a coil current setting unit 35 for determining an electromagnetic force margin and a current based on information obtained by the brake state detection unit 34 (past operation state). The configuration of the electromagnetic brake device according to the fourth embodiment is basically the same as that of any one of the first to third embodiments described above, and the description thereof is omitted here.

  As described above, in the design of the electromagnet, the current for generating an electromagnetic force obtained by adding a surplus force to the spring force is the design holding current, and the current for starting the brake operation when the spring force and the electromagnetic force are equal is the design operation current. On the other hand, in the fourth embodiment, the measurement operation current is measured by the brake condition detection unit 34. The brake state detection unit 34 monitors the current of the brake electromagnet 5 using, for example, a current CT or a shunt resistance. As a typical current change during an emergency operation, the current once increases due to the movement of the movable iron core 2 during the decay of the current and then decreases again (see FIG. 3). Therefore, the brake state detection unit 34 determines the time at which the braking is started by, for example, a current when the differentiation of the current becomes zero, a current when the current increases, a brake operation switch (not shown) provided separately, or the like. The current is detected as a measurement operating current. The detected measurement operating current is stored in a storage unit (not shown) configured from a storage device such as a RAM.

  When the measured operating current is smaller than the designed operating current, the coil current setting unit 35 determines that the estimated electromagnetic force of the electromagnet is higher than the designed. From this, a new set current that generates an electromagnetic force obtained by adding a margin to the spring force is calculated. Actually, it is desirable to reduce the decrease from the design holding current to the newly set current in consideration of an error of the estimated electromagnetic force and the like. FIG. 7 illustrates the relationship between current and electromagnetic force.

  For example, when the brake operation time is longer than a predetermined value, the coil current is set by determining that the capacity of the brake electromagnet 5 is high and reducing the set current of the coil 3, and when the brake operation time is short, the capacity of the brake electromagnet 5 is high. It is judged that the current has deteriorated, and the current of the coil 3 is increased. This makes it possible to ensure a necessary and sufficient electromagnetic force margin. In this case, since the brake current is determined and the coil current is changed, the force of the piezoelectric element 21 and the small electromagnet 22 shown in the first to third embodiments can be reduced.

  Moreover, since the current of the coil 3 can be minimized, the heat generation of the coil 3 can be reduced.

  Further, when the deterioration of the brake electromagnet progresses and the coil current becomes a predetermined value or more, there is an advantage that it can be determined as abnormal and the operation can be stopped or a signal can be transmitted to the outside.

  As described above, in the present embodiment, the same effects as those of the first to third embodiments can be obtained, and furthermore, the coil current of the brake electromagnet is made variable depending on the past operation situation. As a result, the operation assisting means can be reduced in size and the heat generation of the coil can be reduced.

  In addition, in said Embodiment 1-4, although the case where the electromagnetic brake device of this invention was used for an elevator hoist was demonstrated as an example, it is used as brake devices, such as not only in that case but a train, a vehicle, etc. be able to.

It is sectional drawing which shows the structure of the electromagnetic brake device by Embodiment 1 of this invention. It is explanatory drawing which showed the relationship between the electric current and electromagnetic force in the electromagnetic brake device by Embodiment 1 of this invention with the graph. It is explanatory drawing which compared the time change of the electric current in the electromagnetic brake device by Embodiment 1 of this invention with the conventional apparatus. It is sectional drawing which shows the structure of the electromagnetic brake device by Embodiment 2 of this invention. It is sectional drawing which shows the structure of the electromagnetic brake device by Embodiment 3 of this invention. It is the circuit diagram which showed the structure of the drive circuit of the electromagnetic brake by Embodiment 4 of this invention. It is explanatory drawing which showed the relationship between the electric current and electromagnetic force in the electromagnetic brake device by Embodiment 4 of this invention with the graph.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fixed iron core 2 Movable iron core 3 Coil 4 Spring 10 Brake pad 11 Rotating body 21 Piezoelectric element 22 Small electromagnet 30 Power supply 31 Switch 32 Diode 33 Discharge resistance 34 Brake condition detection part 35 Coil current setting part.

Claims (5)

A fixed iron core that is fixed, a movable iron core that is movably provided with respect to the fixed iron core, a coil that generates magnetic flux with respect to the iron core, and a reaction force that is provided on the fixed iron core and that applies a reaction force to the movable iron core. An electromagnetic brake device having a brake electromagnet composed of a spring and braking the operation of a braking object with the force of the brake electromagnet,
An electromagnetic brake device comprising: an operation assisting means for reducing time of electromagnetic force of the brake electromagnet before starting the braking operation of the brake electromagnet, which is faster in time response than the brake electromagnet. The operation assisting means is provided with respect to the movable iron core, and is composed of a piezoelectric element for applying a reaction force to the movable iron core so that the movable iron core moves in a direction away from the fixed iron core.
The electromagnetic brake device according to claim 1, wherein the piezoelectric element widens a gap between the fixed iron core and the movable iron core of the brake electromagnet before the brake electromagnet starts a braking operation. The operation assisting means is provided with respect to the movable iron core, and applies a reaction force to the movable iron core so that the movable iron core moves in a direction away from the fixed iron core. It is composed of small electromagnets,
The electromagnetic brake device according to claim 1, wherein the small electromagnet widens a gap between the fixed iron core and the movable iron core of the brake electromagnet before the brake electromagnet starts a braking operation. The operation assisting means is composed of a small electromagnet smaller than the brake electromagnet,
The small electromagnet connects the fixed iron core and the movable iron core of the brake electromagnet by a movable iron core provided in the small electromagnet before the brake electromagnet starts a braking operation, and the fixed of the brake electromagnet. The electromagnetic brake device according to claim 1, wherein the magnetic flux between the iron core and the movable iron core is bypassed to the movable iron core of the small electromagnet. Brake status detection means for detecting, as operating status information, current at the time when the brake electromagnet starts braking;
A coil current setting unit that determines a coil current to be passed through the coil of the brake electromagnet based on the operation status information obtained by the brake status detection unit;
The electromagnetic brake device according to any one of claims 1 to 4, wherein a coil current flowing through the coil of the brake electromagnet is variable.

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