JP2010216616A - Electromagnetic brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic brake in which the exciting power capacity of a coil can be reduced. <P>SOLUTION: Ones of electromagnetic coils 11a, 11b and the coil portions are disposed radially inward of the coil storage parts of yokes as holding coils 11a1, 11b1. The others of the electromagnetic coils 11a, 11b and the coil portions are disposed radially outward of the holding coils 11a1, 11b1 as acceleration coils 11a2, 11b2. The holding coils 11a1, 11b1 allow a current to flow therein from the start of braking release operation to the application of braking. The acceleration coils 11a2, 11b2 allow a current to flow therein in an acceleration period at the start of the braking release operation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic brake that applies braking by pressing a braking piece with a braking spring and releases braking with an electromagnet, and particularly relates to a coil arrangement and excitation method of an electromagnet composed of two electromagnetic coils or coil portions.

  Conventionally, an electromagnetic brake in which one electromagnet is constituted by two electromagnetic coils has been disclosed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 04-203628

An object of the present invention is to reduce the excitation power source capacity of the holding coil. That is, since the required magnetomotive force U of the electromagnetic coil U = the number of turns N × the coil current I _C and the coil current I _C = the excitation voltage E _C / the coil resistance R _C , if the coil diameter is larger than the required number of turns, the wire length Since the self-resistance becomes large as a result of this, a power source that generates a high voltage is required to pass the required current. Further, since the power consumption W _{C of the} coil is W _C = I _C ² × _RC , when the coil diameter is large, the self-resistance is large and the power consumption is also large.

  The electromagnet of the electromagnetic brake proposed in Patent Document 1 is composed of two electromagnetic coils in one electromagnet, one is a main coil that is always used, and the other is an auxiliary coil that is used in an emergency. As an arrangement of the two electromagnetic coils, a case is disclosed in which they are arranged in the radial direction on the yoke side, arranged in the axial direction, or one on the yoke side and the movable iron piece side. The conventional method of Patent Document 1 is an arrangement of a regular main coil and an emergency auxiliary coil, and is not a case where two electromagnetic coils are always used. Furthermore, there is no disclosure about a specific excitation method of two electromagnetic coils for braking release operation and reduction of excitation power source capacity.

  An object of the present invention is to provide an electromagnetic brake capable of reducing the excitation power capacity of a coil when two electromagnetic coils or coil portions are radially overlapped on one electromagnet and each coil is excited by an individual power source. In offer.

  In order to achieve the above object, according to a first aspect of the present invention, the present invention comprises a braking application means for applying a braking force by applying a pressing force to a braking piece facing a braked body with a braking spring, an electromagnetic coil, and a yoke. In the electromagnetic brake, the electromagnetic coil is composed of two electromagnetic coils or coil portions that are cylindrical and are arranged so as to overlap in the radial direction. Alternatively, one of the coil parts is arranged as a holding coil inside the yoke coil storage part in the radial direction, and the other one of the electromagnetic coil or coil part is arranged as a promotion coil radially outside the holding coil, The holding coil passes a current from the start of the braking release operation to the braking addition, and the promotion coil passes a current during the promotion period of the start of the braking release operation.

  With this configuration, when two electromagnetic coils are arranged in a radial direction on one electromagnet, an electromagnetic brake capable of reducing the exciting power supply capacity of the coil can be obtained.

  According to a second aspect of the present invention, in the first aspect, the holding coil is controlled so as to have a constant current according to a current command value from the start of the braking release operation to the addition of the braking.

  With this configuration, the same effect as in the first aspect can be obtained.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the holding coil is controlled to have a constant current according to a current command value from the start of the braking release operation to the addition of the braking.

  With this configuration, the same effect as in the first aspect can be obtained.

  According to the present invention, when two electromagnetic coils or coil portions are arranged in a radial direction on one electromagnet and each coil is excited by an individual power source, an electromagnetic brake that can reduce the excitation power capacity of the coil is provided. Obtainable.

1 is an overall configuration of an electromagnetic brake when applied to, for example, an elevator hoisting machine according to an embodiment of the present invention. FIG. 2 is a side view showing one side (left side in FIG. 1) of a pair of electromagnets in FIG. 1, which is an electromagnet formed by overlapping two cylindrical electromagnetic coils in the radial direction. It is an AA view in the front view of FIG. It is an excitation circuit of the electromagnetic coil of FIG. It is a timing diagram which shows operation | movement of a brake, and excitation of an electromagnetic coil. It is the FIG. 2 equivalent figure which consists of a holding coil and a promotion coil of the two coil parts from which winding direction differs by one electromagnetic coil in 2nd Embodiment. FIG. 6 is a diagram equivalent to FIG. 4 in the excitation circuit of the electromagnetic coil 30a of FIG.

  Hereinafter, embodiments of the electromagnetic brake of the present invention will be described in detail.

  The invention according to Embodiment 1 of the present invention will be described with reference to FIGS.

  In FIG. 1, 1 is a drive sheave of an elevator hoisting machine. A car 3 is suspended on one side of a main rope 2 wound around the drive sheave 1, and a counterweight 4 is suspended on the other side in a suspending manner. The driving sheave 1 is driven by the hoisting motor 5 and the car 3 and the counterweight 4 are moved up and down. Reference numeral 6 denotes a brake drum as a braked body, which is installed on a shaft 5 a that couples the hoisting motor 5 and the drive sheave 1. A pair of braking pieces 7 abut on the braking surface 6 a of the brake drum 6. A pair of braking arms 8 includes the braking piece 7 in the intermediate portion 8c and rotatably supports the one end portion 8a. Reference numeral 9 denotes a pair of braking springs, which are arranged on the other end portion 8b of the braking arm 8 so that the braking piece 7 applies a pressing force to the braking surface 6a.

  A pair of fixed electromagnets 10a and 10b are provided in the vicinity of the other end portion 8b of the braking arm 8 so as to release the pressing force of the braking spring 9. The electromagnets 10a and 10b are respectively composed of a holding coil 11a1 having two coil portions and an electromagnetic coil 11a and a yoke 12a made up of an accelerating coil 11a2, and an electromagnetic coil 11b and a yoke made up of a holding coil 11b1 made of two coils and an accelerating coil 11b2. The electromagnets 10a and 10b have magnetic pole surfaces 13a and 13b, and movable pieces 14a and 14b are arranged to face the magnetic pole surfaces 13a and 13b. The movable pieces 14a and 14b are coupled to one ends of the shafts 15a and 15b. The other ends of the shafts 15a and 15b are connected to the other end portion 8b of the braking arm 8 to drive the braking arm 8 and to the braking piece 7. The shafts 15a and 15b are slidably supported at the central portions of the yokes 12a and 12b. That is, the left electromagnet 10a, the braking spring 9, and the braking piece 7 system and the right electromagnet 10b, the braking spring 9, and the braking piece 7 system are configured in two sets that function independently.

  Reference numeral 16 denotes a coil excitation power source that controls the current by energizing the electromagnetic coils 11a and 11b of the pair of electromagnets 10a and 10b. Reference numeral 17 denotes a contact of an electromagnetic contactor that energizes and interrupts the electromagnetic coils 11a and 10b of the pair of electromagnets 10a and 10b.

  2 and 3, since the pair of electromagnets 10a and 10b in FIG. 1 have the same structure and the same configuration, the left electromagnet 10a will be described. The electromagnetic coil 11a is cylindrical and includes a holding coil 11a1 and a promotion coil 11a2. That is, the brake release holding coil 11a1 whose one side coil has a small diameter, and the brake release promotion coil 11a2 whose other side coil has a large diameter and overlaps the outside in the radial direction of the holding coil 11a1, and the yoke 12a. It is arrange | positioned at the coil accommodating part 12c of a recessed part. The holding coil 11a1 and the exciting coil 11a2 are excited by the holding power source 18 for releasing the brake and the promoting power source 19 for releasing the brake, respectively, and are excited so that the directions of the magnetic fluxes 18a and 19a generated in the yoke 12a are the same. . As described above, the movable piece 14a is supported by the shaft 15a, and this shaft 15a is slidably supported by the bearing 21 provided in the hole 20 in the central portion of the yoke 12a.

  4, the holding coil 11a1 of the left electromagnetic coil 11a in FIG. 1 and the holding coil 11b1 of the right electromagnetic coil 11b are connected in parallel and excited by the holding power supply 18 through the contact 17a. At this time, the holding power source 18 is controlled so that the current i 1 flowing through the holding coils 11 a 1 and 11 b 1 is detected by the current detection means 22 and fed back to obtain a constant current output commanded by the current command value 23. The holding power source 18 generates a DC variable voltage by a switching element, for example, and adjusts the current. Similarly, the promotion coils 11a2 and 11b2 are connected in parallel and excited by the promotion power source 19 via the contact point 17b. Reference numerals 24 and 25 denote current limiting resistors, which are inserted into the holding power supply 18 and the accelerating power supply 19 as necessary for current adjustment. Reference numerals 26 and 27 are normally closed contacts that are opened in an emergency such as an emergency stop of the elevator. A diode 28 and a resistor 29 connected in series are connected in parallel to the holding coils 11a1, 11b1 and the promotion coils 11a2, 11b2, respectively, and when the contacts 26, 27 are opened, the holding coils 11a1, 11b1 and the promotion coil 11a2, 11b2 reflux current is consumed.

  Next, referring to FIG. 4 and based on FIG. 5, the operation from the release of braking to the addition of braking according to this embodiment, that is, the operation from time T1 to time T4 will be described.

  The contacts 17a and 17b of the magnetic contactor supplied with power supply are connected at time T1, a constant current i1 flows from the holding power supply 18 according to a step-like current command, and the currents ia1 and ib1 flow to the holding coils 11a1 and 11b1 according to the time constant of the circuit Current i2 flows from the accelerating power source 19, and currents ia2 and ib2 flow through the accelerating coils 11a2 and 11b2 according to the circuit time constant. At time T2, the contact point 17b is cut off, and the currents ia2 and ib2 from the accelerating power source 19 to the accelerating coils 11a2 and 11b2 are cut off. The current decreases and becomes zero according to the time constant of the circuit, and the current flowing through the electromagnetic coils 11a and 11b is maintained. Only the currents ia1 and ib1 of the coils 11a1 and 11b1 are obtained. At time T3, the current command of the holding coils 11a1 and 11b1 is cut off, and the contact 17a is cut off to cut off the currents ia1 and ib1 from the holding power supply 18 to the holding coils 11a1 and 11b1, and the current decreases according to the time constant of the circuit. It disappears at that point.

  That is, the period from T1 to T3 is a braking release operation, and the period from T1 to T2 is a braking release promotion period, and both the holding power source 18 and the acceleration power source 19 are made effective in order to speed up the braking release operation. As a result, magnetic fluxes generated by the currents ia1 and ib1 of the holding power supply 18 and the currents ia2 and ib2 of the accelerating power supply 19 are added, so that a large electromagnetic attraction force is generated in the electromagnet 10a shown in FIG. To speed up the brake release operation. The time from T1 to T2 is about several seconds when the elevator starts running.

  The period from T2 to T3 is a braking release holding period, and only the holding power source 18 is effective and holds the braking release state. That is, if the movable piece 14a is attracted, the gap is reduced and the magnetic resistance of the magnetic circuit is reduced. Therefore, even if the current is reduced, the movable piece 14a can be kept attracted. The time from T2 to T3 is until the elevator runs at a substantially constant speed and stops. The acceleration period of the brake release is about several seconds, which is very short compared with the brake release holding period, and is almost negligible in the entire period of brake release.

  After the time T3, the braking application operation is performed and the currents ia1 and ib1 of the holding power supply 11a1 and 11b1 on the holding power supply 18 side disappear, and the pressing force of the braking piece 7 is restored by the braking spring 9 of FIG. Become.

  The constant current control of the holding coils 11a1 and 11b1 is caused by fluctuations in the voltage of the power supply drawn into the building, particularly voltage drop, and when the coil is energized, heat is generated and the self-resistance value increases and the current value decreases. As a result, the release of braking cannot be maintained, the braking piece 7 is in a half-open state and rotates by rubbing against the brake drum 6, and the braking piece 7 is worn and the braking performance is deteriorated. For this reason, it is necessary to reliably maintain the brake release during the traveling of the elevator.

  In short, the holding power supply 18 continuously controls the current value to be the commanded current value from T1 to T3 by one-step wide pulse current command, and causes the coil currents ia1 and ib1 to flow through the holding coils 11a1 and 11b1. The accelerating power source 19 supplies currents ia2 and ib2 to the accelerating coils 11a2 and 11b2 for a short time from T1 to T2 at the initial stage of braking release. Then, both the holding power source 18 and the accelerating power source 19 are set to a coil current that speeds up the brake release, and the holding power source 18 is set to a current that holds the brake release.

  By the way, the holding power source 18 is expensive because it performs constant current control. High-capacity ones with large output voltage and current are more expensive. Therefore, it is important to use a power supply with a capacity as small as possible. The relationship between magnetomotive force, number of turns, current, voltage, resistance, and power of the holding coils 11a1 and 11b1 is expressed by the following equations (1) to (4).

すなわち、電磁石１０ａの電磁吸引力を決定する所要起磁力Ｕは(1)、(2)式から、巻数Ｎ、励磁電圧Ｅ_Ｃ、コイル抵抗Ｒ_Ｃで決まる。コイル抵抗Ｒ_Ｃは巻線の断面積、固有抵抗が一定であれば、(4)式の通り、コイル長さｌ_Ｃが長いほど大きくなる。つまり、巻数Ｎが一定であればコイル抵抗Ｒ_Ｃが大きいと、大きい励磁電圧Ｅ_Ｃが必要となる。そして、コイル消費電力Ｗ_Ｃは(3)式の通り、コイル抵抗Ｒ_Ｃが大きいと、大きくなる。

That is, the required magnetomotive force U to determine the electromagnetic attraction force of the electromagnet 10a is (1), (2) from the equation, the number of turns N, the excitation voltage E _C, determined by the coil resistance R _C. If the cross-sectional area of the winding and the specific resistance are constant, the coil resistance _RC increases as the coil length l _C increases as shown in the equation (4). That is, if the number of turns N is constant, if the coil resistance _RC is large, a large excitation voltage E _C is required. Then, as the coil power consumption W _C is (3), the coil resistance R _C is large, increases.

In short, the smaller the coil resistance _RC , the lower the voltage and power supply capacity, and the lower the temperature rise. Accordingly, it is effective to provide the holding coils 11a1 and 11b1 on the inner side of the coil housing portion 12c and to have a small diameter, that is, to shorten the coil length l _C with respect to the required number of turns.

  That is, when two electromagnetic coil portions are arranged in a radial direction on one electromagnet, in this embodiment, the holding coil of the coil portion for constant current control is arranged inside the yoke coil housing portion in the radial direction. The other accelerating coil is disposed radially outside the holding coil. With this configuration, the coil length of the holding coil can be shortened to obtain an effect that the excitation voltage and the power source capacity can be reduced.

  Although the acceleration power source 19 has been described without current control, current may be fed back in the same manner as the holding power source 18 so that a constant current flows during the braking release acceleration period from T1 to T2 in FIG.

  Next, a second embodiment will be described with reference to FIGS. This embodiment is different from the first embodiment in the case where two coil portions having different winding directions are formed from one winding to form one electromagnetic coil.

  FIG. 6 is a diagram corresponding to FIG. 2 composed of a holding coil and an accelerating coil of two coil portions having different winding directions in one electromagnetic coil, and FIG. 7 is a diagram corresponding to FIG. The same parts as those in FIGS. 2 and 4 are denoted by the same reference numerals and description thereof is omitted.

  6, description will be made with the electromagnet 10a on the left side of FIG. 1 as in FIG. The electromagnetic coil 30a has a cylindrical shape, and the coil is wound in one electromagnetic coil 30a, for example, a holding coil 30a1 having a small right-handed diameter and a left-handed winding that has a large diameter and overlaps the outer diameter side of the holding coil 30a1. It is continuously wound with one winding so as to be two coil portions with 30a2, and is formed as one electromagnetic coil 30a. Excitation to the holding coil 30a1 and the promotion coil 30a2 is performed by the holding power source 18 and the promotion power source 19, respectively. If the current direction of the accelerating coil 30a2 is reversed with respect to the holding coil 30a1, the directions of the magnetic fluxes 31a1 and 31a2 generated in the holding coil 30a1 and the accelerating coil 30a2 are the same, and the electromagnetic flux of the electromagnet 10a becomes an addition of the magnetic flux. The suction power increases.

  In FIG. 7, as in FIG. 4, the holding coil 30a1 of the electromagnetic coil 30a and the holding coil 30b1 of the electromagnetic coil 30b are connected in parallel and excited by the holding power supply 18 via the contact 17a. At this time, the holding power supply 18 is controlled such that the current i1 flowing through the holding coils 30a1 and 30b1 is detected by the current detection means 22 and fed back, so that a constant current output of the current command value 23 is obtained. Similarly, the promotion coils 30a2 and 30b2 are connected in parallel and excited by the promotion power source 19 via the contact point 17b. The intermediate points 32a and 32b where the winding directions of the electromagnetic coils 30a and 30b are reversed are connected so that the holding power source 18 and the accelerating power source 19 have the same polarity. The current i1 flows through the holding coils 30a1 and 30b1, the currents ia1 and ib1, respectively, and the current i2 flows through the promotion coils 30a2 and 30b2, respectively. As a result, magnetic flux due to currents ia1 and ia2 is generated in the electromagnetic coil 30a, and magnetic flux due to currents ib1 and ib2 is generated in the electromagnetic coil 30b.

  The time course of excitation of the holding coils 30a1 and 30b1 and the promotion coils 30a2 and 30b2 is the same as that in FIG. 5 and corresponds to the holding coils 11a1 and 11b1 and the promotion coils 11a2 and 11b2, respectively. Moreover, you may carry out electric current control of the promotion power supply 19 similarly to 1st Embodiment.

  The effect of this example is the same as that of the first embodiment, and it is possible to form one electromagnetic coil by winding with one coil without using two individual coils. An effect that can be reduced is obtained.

7 Braking piece 9 Braking spring 10a, 10b Electromagnet 11a, 11b Electromagnetic coil 11a1, 11b1 Holding coil 11a2, 11b2 Promoting coil 12a, 12b yoke 23 Current command value 30a, 30b Electromagnetic coil 30a1, 30b1 Holding coil 30a2, 30b2 Promoting coil

Claims (3)

The brake adding unit applies a braking force by applying a pressing force to the braking piece facing the brake target with a braking spring, and the brake releasing unit releases the braking force with an electromagnet including an electromagnetic coil and a yoke. In the electromagnetic brake, the electromagnetic coil is composed of two cylindrical electromagnetic coils or coil portions and is arranged to overlap in the radial direction.
One of the electromagnetic coil or the coil portion is disposed as a holding coil inside the yoke coil housing portion in the radial direction, and the other of the electromagnetic coil or the coil portion is disposed as a promotion coil radially outside the holding coil. The holding coil passes a current from the start of the braking release operation to the braking addition, and the acceleration coil passes a current during the promotion period at the start of the braking release operation.   2. The electromagnetic brake according to claim 1, wherein one holding coil and the other acceleration coil of the two electromagnetic coils or coil portions have opposite winding directions.   3. The electromagnetic brake according to claim 1, wherein the holding coil is controlled so as to have a constant current according to a current command value from the start of the braking release operation to the addition of braking.

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