阅读说明：本技术 电磁继电器 (Electromagnetic relay ) 是由 川口直树 箕轮亮太 针持裕之 小川真一 大塚航平 岩坂博之 于 2020-08-28 设计创作，主要内容包括：一种电磁继电器,本发明的目的在于,在电磁继电器中降低触点接触时的反弹。驱动电路控制向线圈的电流。驱动电路在第1期间使电流以第1上升速度上升。第1期间包括从使电流流过线圈的开始时刻到可动触点与固定触点的接触时刻之前为止的期间。驱动电路在第2期间中使电流以比第1上升速度大的第2上升速度上升。第2期间包含接触时刻后的期间。(An electromagnetic relay in which contact bounce is reduced. The drive circuit controls the current to the coil. The drive circuit increases the current at a1 st increase rate in the 1 st period. The 1 st period includes a period from a start point of current flowing through the coil to a point before a contact point between the movable contact and the fixed contact. The drive circuit increases the current at a2 nd increase rate that is greater than the 1 st increase rate in the 2 nd period. The 2 nd period includes a period after the contact time.)

1. An electromagnetic relay is characterized by comprising:

a fixed terminal;

a fixed contact connected to the fixed terminal;

a movable contact piece which is movable in an opening direction and a closing direction with respect to the fixed terminal;

a movable contact connected to the movable contact piece and disposed opposite to the fixed contact;

a coil that generates an electromagnetic force for moving the movable contact piece; and

a drive circuit that controls a current flowing to the coil,

as far as the drive circuit is concerned,

increasing a current at a1 st increasing speed during a1 st period including a period from a start time of flowing the current through the coil to before a contact time of the movable contact with the fixed contact,

and increasing the current at a2 nd increasing speed greater than the 1 st increasing speed in a2 nd period including a period after the contact timing.

2. The electromagnetic relay according to claim 1,

the drive circuit holds the current flowing through the coil at a current value higher than that in the 1 st period in the 3 rd period after the 2 nd period.

3. The electromagnetic relay according to claim 2,

the drive circuit reduces the current flowing through the coil to a current value lower than the current value in the 3 rd period in a4 th period after the 3 rd period.

4. An electromagnetic relay according to any one of claims 1 to 3,

the 1 st period is longer than the 2 nd period.

5. An electromagnetic relay according to any one of claims 1 to 3,

further comprising a contact voltage detection means for detecting the voltages at the movable contact and the fixed contact,

the drive circuit detects the contact timing based on the voltage detected by the contact voltage detection unit.

6. The electromagnetic relay according to claim 5,

the drive circuit starts the 2 nd period based on the voltage detected by the contact voltage detection means.

7. The electromagnetic relay according to any one of claims 1 to 3, characterized by further comprising:

a movable mechanism connected to the movable contact piece; and

a movable iron core connected to the movable mechanism and moved by an electromagnetic force generated by the coil,

the 1 st period includes a period from the start time to the start of movement of the movable core.

Technical Field

The present invention relates to an electromagnetic relay.

Background

Some electromagnetic relays reduce power consumption at the time of contact holding by reducing current to a coil after contact. For example, in the electromagnetic relay of patent document 1, the coil voltage is controlled by PWM (Pulse Width Modulation) control. Specifically, the duty ratio of the coil voltage is set to 100% from the start of driving the contact to the completion of contact. And while the contacts are held, the duty cycle is reduced. This reduces the current to the coil when the contact is held.

Patent document 1: japanese laid-open patent publication No. 1-132108

In the above-described electromagnetic relay, an excessive current flows in the coil before the contacts are contacted. Therefore, the collision energy of the contact becomes large, and the bounce at the time of contact of the contact becomes large.

Disclosure of Invention

The invention aims to reduce contact bounce in an electromagnetic relay.

An electromagnetic relay according to one embodiment includes a fixed terminal, a fixed contact, a movable contact piece, a movable contact, a coil, and a drive circuit. The fixed contact is connected with the fixed terminal. The movable contact piece is movable in an opening direction and a closing direction with respect to the fixed terminal. The movable contact is connected to the movable contact piece and arranged to face the fixed contact. The coil generates an electromagnetic force that moves the movable contact piece. The drive circuit controls the current to the coil. The drive circuit increases the current at a1 st increase rate in the 1 st period. The 1 st period includes a period from a start point of current flowing through the coil to a point before a contact point of the movable contact with the fixed contact. The drive circuit increases the current at a2 nd increase rate that is greater than the 1 st increase rate in the 2 nd period. The 2 nd period includes a period after the contact time.

In the electromagnetic relay according to this embodiment, in the 1 st period, the current flows through the coil at a slower rising speed than in the 2 nd period. Therefore, the collision energy of the contact can be reduced. Thus, bounce of the contacts is reduced. In the 2 nd period, a current flows through the coil at a rising speed faster than that in the 1 st period. Therefore, the pressing force of the movable contact to the fixed contact increases. Thus, the bounce of the contacts is further reduced.

The drive circuit may hold the current to the coil at a current value higher than the current value in the 1 st period in the 3 rd period after the 2 nd period. In this case, the contact points can be stably brought into contact with each other by rapidly converging the bounce of the contact points.

The drive circuit may reduce the current to the coil to a current value lower than the current value in the 3 rd period in the 4 th period after the 3 rd period. In this case, power consumption during contact holding can be reduced.

The 1 st period may be longer than the 2 nd period. In this case, the collision energy of the contact can be reduced by gradually increasing the current to the coil.

The electromagnetic relay may further include a contact voltage detection unit. The contact voltage detecting unit may also detect the voltages of the movable contact and the fixed contact. The drive circuit may detect the contact timing based on the voltage detected by the contact voltage detection means. In this case, the contact of the contact can be detected with high accuracy from the voltage at the movable contact.

The drive circuit may start the 2 nd period based on the voltage detected by the contact voltage detection means. In this case, the 2 nd period can be appropriately started according to the contact timing of the contact.

The electromagnetic relay may further include a movable mechanism and a movable iron core. The movable mechanism may be connected to the movable contact piece. The movable iron core may be connected to the movable mechanism and moved by an electromagnetic force generated from the coil. The 1 st period may include a period from the start point to the start of the movement of the movable core. In this case, the current to the coil is gradually increased until the movable core starts to move, so that the collision energy of the contact can be reduced.

According to the present invention, in the electromagnetic relay, the bounce at the time of contact of the contact can be reduced.

Drawings

Fig. 1 is a side sectional view of an electromagnetic relay in an open state according to an embodiment.

Fig. 2 is a side sectional view of the electromagnetic relay showing a closed state.

Fig. 3 is a schematic diagram showing the configuration of the drive circuit.

Fig. 4 is a timing chart showing control of the electromagnetic relay by the drive circuit.

Fig. 5 is a side cross-sectional view showing an electromagnetic relay according to a modification.

Description of reference numerals:

10: a movable mechanism; 11: 1 st fixed terminal; 13: a movable contact piece; 14: 1 st fixed contact; 16: 1 st movable contact; 31: a movable iron core; 32: a coil; 41: a drive circuit; 48: a contact voltage detection unit.

Detailed Description

Hereinafter, the electromagnetic relay 1 according to the embodiment will be described with reference to the drawings. Fig. 1 is a side cross-sectional view showing an electromagnetic relay 1 according to an embodiment. As shown in fig. 1, an electromagnetic relay 1 includes a contact device 2, a housing 3, and a drive device 4.

In the following description, the respective directions of up, down, left, and right refer to the respective directions of up, down, left, and right in fig. 1. In detail, a direction from the driving device 4 toward the contact device 2 is defined as an upward direction. The direction from the contact arrangement 2 towards the drive arrangement 4 is defined as downward. In fig. 1, a direction intersecting with the up-down direction is defined as a left-right direction. A direction intersecting the up-down direction and the left-right direction is defined as a front-rear direction. The front-rear direction is a direction perpendicular to the paper surface of fig. 1. However, these directions are defined for convenience of explanation, and the arrangement direction of the electromagnetic relay 1 is not limited.

The contact arrangement 2 is arranged in a housing 3. The contact device 2 includes a movable mechanism 10, a1 st fixed terminal 11, a2 nd fixed terminal 12, a movable contact piece 13, a1 st fixed contact 14, a2 nd fixed contact 15, a1 st movable contact 16, and a2 nd movable contact 17. The 1 st and 2 nd fixing terminals 11 and 12 are made of a material having conductivity, such as copper or a copper alloy, for example. The 1 st fixed contact 14 is connected to the 1 st fixed terminal 11. The 2 nd fixed contact 15 is connected to the 2 nd fixed terminal 12. The 1 st fixed contact 14 and the 2 nd fixed contact 15 are arranged apart from each other in the left-right direction.

The 1 st fixed terminal 11 includes a1 st contact supporting portion 21 and a1 st external terminal portion 22. The 1 st contact point support portion 21 faces the movable contact piece 13. The 1 st fixed contact 14 is connected to the 1 st contact support portion 21. The 1 st external terminal portion 22 is connected to the 1 st contact supporting portion 21. The 1 st external terminal portion 22 protrudes outward from the housing 3.

The 2 nd fixed terminal 12 includes a2 nd contact supporting portion 23 and a2 nd external terminal portion 24. The 2 nd contact supporting portion 23 faces the movable contact piece 13. The 2 nd fixed contact 15 is connected to the 2 nd contact support portion 23. The 2 nd external terminal portion 24 is connected to the 2 nd contact supporting portion 23. The 2 nd external terminal portion 24 protrudes outward from the housing 3. Specifically, the 1 st external terminal portion 22 and the 2 nd external terminal portion 24 protrude upward from the housing 3.

The movable contact piece 13 extends in the left-right direction. The movable contact piece 13 is disposed to face the 1 st contact supporting portion 21 of the 1 st fixed terminal 11 and the 2 nd contact supporting portion 23 of the 2 nd fixed terminal 12 in the vertical direction. The movable contact piece 13 is disposed so as to be movable in the closing direction Z1 and the opening direction Z2. The closing direction Z1 is a direction (upward in fig. 1) in which the movable contact piece 13 approaches the 1 st fixed terminal 11 and the 2 nd fixed terminal 12. The opening direction Z2 is a direction (downward in fig. 1) in which the movable contact piece 13 is separated from the 1 st fixed terminal 11 and the 2 nd fixed terminal 12.

The 1 st movable contact 16 and the 2 nd movable contact 17 are connected to the movable contact piece 13. The 1 st movable contact 16 and the 2 nd movable contact 17 are arranged apart from each other in the left-right direction. The 1 st movable contact 16 is opposed to the 1 st fixed contact 14 in the up-down direction. The 2 nd movable contact 17 is opposed to the 2 nd fixed contact 15 in the up-down direction.

The movable mechanism 10 supports the movable contact piece 13. The movable mechanism 10 is disposed so as to be movable together with the movable contact piece 13 in the closing direction Z1 and the opening direction Z2. The movable mechanism 10 includes a drive shaft 19, a1 st holding member 25, a2 nd holding member 26, and a contact spring 27. The drive shaft 19 extends in the up-down direction. The drive shaft 19 is connected to the movable contact piece 13. The drive shaft 19 extends downward from the movable contact piece 13. The movable contact piece 13 is provided with a hole 13 a. The drive shaft 19 is inserted into the hole 13 a. The movable contact piece 13 is relatively movable with respect to the drive shaft 19 in the closing direction Z1 and the opening direction Z2.

The drive shaft 19 is arranged to be movable between a closed position and an open position. Fig. 1 shows the drive shaft 19 in the disconnected position. As shown in fig. 1, when the drive shaft 19 is in the off position, the movable contacts 16, 17 are separated from the fixed contacts 14, 15. Fig. 2 shows the drive shaft 19 in the closed position. As shown in fig. 2, when the drive shaft 19 is in the closed position, the movable contacts 16, 17 are in contact with the fixed contacts 14, 15.

The 1 st holding member 25 is fixed to the drive shaft 19. The contact spring 27 is disposed between the movable contact piece 13 and the 1 st holding member 25. The contact spring 27 biases the movable contact piece 13 in the closing direction Z1 in a state where the movable contacts 16 and 17 are in contact with the fixed contacts 14 and 15. The 2 nd holding member 26 is fixed to the drive shaft 19. The movable contact piece 13 is located between the 2 nd holding member 26 and the contact spring 27.

The driving device 4 operates the movable contact piece 13 by electromagnetic force. The drive device 4 moves the movable mechanism 10 in the closing direction Z1 and the opening direction Z2. Thereby, the driving device 4 moves the movable contact piece 13 in the closing direction Z1 and the opening direction Z2. The driving device 4 includes a movable iron core 31, a coil 32, a fixed iron core 33, a yoke 34, and a return spring 35.

The movable iron core 31 is connected to the drive shaft 19. The movable iron core 31 is provided to be movable in the closing direction Z1 and the opening direction Z2. The coil 32 generates an electromagnetic force that moves the movable iron core 31 in the closing direction Z1 when a current is applied thereto. The fixed core 33 is disposed to face the movable core 31. The return spring 35 is disposed between the movable iron core 31 and the fixed iron core 33. The return spring 35 biases the movable iron core 31 in the opening direction Z2.

The yoke 34 is disposed so as to surround the coil 32. The yoke 34 is disposed on the magnetic circuit constituted by the coil 32. The yoke 34 is disposed above the coil 32, on the side of the coil 32, and below the coil 32.

Next, the operation of the electromagnetic relay 1 will be described. When the coil 32 is not energized, the drive device 4 is not excited. In this case, the drive shaft 19 is pressed in the opening direction Z2 together with the movable iron core 31 by the elastic force of the return spring 35. The drive shaft 19 is thus in the disconnected position shown in fig. 1. In this state, the movable contact piece 13 is also pressed in the opening direction Z2 via the movable mechanism 10. Therefore, when the drive shaft 19 is in the off position, the 1 st movable contact 16 and the 2 nd movable contact 17 are separated from the 1 st fixed contact 14 and the 2 nd fixed contact 15.

When the coil 32 is energized, the driving device 4 is excited. In this case, the movable iron core 31 moves in the closing direction Z1 against the elastic force of the return spring 35 by the electromagnetic force of the coil 32. Thereby, the drive shaft 19 moves in the closing direction Z1 together with the movable contact piece 13. Thus, as shown in fig. 2, the drive shaft 19 moves to the closed position. As a result, as shown in fig. 2, when the drive shaft 19 is in the closed position, the 1 st movable contact 16 and the 2 nd movable contact 17 are in contact with the 1 st fixed contact 14 and the 2 nd fixed contact 15, respectively.

When the current flowing through the coil 32 stops and is demagnetized, the movable iron core 31 is pressed in the opening direction Z2 by the elastic force of the return spring 35. Thereby, both the drive shaft 19 and the movable contact piece 13 move in the opening direction Z2. Therefore, as shown in fig. 1, the movable mechanism 10 moves to the off position. As a result, when the movable mechanism 10 is in the off position, the 1 st movable contact 16 and the 2 nd movable contact 17 are separated from the 1 st fixed contact 14 and the 2 nd fixed contact 15.

The control of the current flowing through the coil 32 as described above is performed by the drive circuit 41 shown in fig. 3. The electromagnetic relay 1 includes a drive circuit 41. The drive circuit 41 switches the electromagnetic relay 1 between an open state and a closed state in accordance with a control signal from the outside. The drive circuit 41 controls the coil current and the coil voltage supplied to the coil 32. In detail, the driving circuit 41 controls the coil voltage by PWM (Pulse Width Modulation) control.

The drive circuit 41 includes a power supply circuit 42, a control circuit 43, a switch circuit 44, a return circuit 45, a coil voltage sensor 46, a coil current sensor 47, and a contact voltage detection unit 48. The power supply circuit 42 is connected to an external power supply not shown. The power supply circuit 42 includes, for example, a switch. The power supply circuit 42 is controlled by an external control signal, and switches on/off of power to the drive circuit 41.

The control circuit 43 includes, for example, a processor. The control circuit 43 outputs a pulse signal to the switching circuit 44. The switching circuit 44 includes a Semiconductor switching element such as a MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor), for example. The switching circuit 44 switches on/off of the voltage input from the power supply circuit 42 to the coil 32 in accordance with a pulse signal from the control circuit 43.

The return circuit 45 is connected in parallel with the coil 32. The return circuit 45 includes, for example, a diode element. The coil voltage sensor 46 detects a coil voltage. The coil voltage sensor 46 inputs a signal indicating the coil voltage to the control circuit 43. The coil current sensor 47 detects a coil current. The coil current sensor 47 inputs a signal indicating the coil current to the control circuit 43. The contact voltage detection unit 48 detects the contact voltage. The contact voltage is the voltage between contacts 14-17. The contact voltage detection unit 48 is, for example, a voltage sensor. However, the contact voltage detection unit 48 may be another detection device such as a photocoupler. The contact voltage detection unit 48 inputs a signal indicating the contact voltage to the control circuit 43.

Fig. 4 is a timing chart showing control of the electromagnetic relay 1 by the drive circuit 41. Fig. 4(a) shows a control signal from the outside. When the control signal indicates off, the electromagnetic relay 1 is turned off. When the control signal indicates on, the electromagnetic relay 1 is in a closed state. Fig. 4(b) shows a coil voltage signal. The coil voltage signal is representative of the coil voltage. Fig. 4(c) shows a coil current. Fig. 4(d) shows a contact signal. The contact signal represents the contact voltage. In the off state of the electromagnetic relay 1, the contact signal indicates off. In the closed state of the electromagnetic relay 1, the contact signal indicates on.

At time T0, the control signal is off. Therefore, the drive circuit 41 does not apply a voltage to the coil 32, and a current does not flow through the coil 32. Therefore, the electromagnetic relay 1 is in the off state, and the contact signal indicates off.

When the control signal is turned on at time T1, the drive circuit 41 applies a coil voltage signal having a voltage value V1 and a duty ratio a1 to the coil 32 during the 1 st period T1-T2. The duty cycle a1 is less than 100%. Thus, the current flows from the 1 st period T1 to the coil 32, and the coil current rises at the 1 st rising speed in the 1 st period T1 to T2. The rising speed of the coil current indicates an amount of increase in the current per unit time. Therefore, the 1 st rising speed is shown as the slope of the coil current in the 1 st period T1-T2 in fig. 4 (c).

In the 1 st period T1 to T2, the coil 32 is energized, whereby the drive device 4 is excited. Thus, in the 1 st period T1-T2, the movable iron core 31 starts to move in the closing direction Z1, and the movable contacts 16 and 17 move in the closing direction Z1. At time T2, the movable contacts 16, 17 are in contact with the fixed contacts 14, 15. The drive circuit 41 detects contact of the contact 1417 based on the contact voltage detected by the coil voltage sensor 46. At this time, the coil current is a current value I1.

When the drive circuit 41 detects contact of the contact 1417, a coil voltage signal having a voltage value V2 and a duty ratio a2 is applied to the coil 32 in the 2 nd period T2-T3. Duty cycle a2 is greater than duty cycle a 1. For example, duty cycle A2 is 100%. However, the duty cycle a2 may also be less than 100%. The voltage value V2 is greater than the voltage value V1. Thus, in the 2 nd period T2T 3, the coil current rises at the 2 nd rising speed. The 2 nd rising speed is larger than the 1 st rising speed. The 2 nd period T2T 3 is shorter than the 1 st period T1T 2. That is, the 1 st period T1T 2 is longer than the 2 nd period T2T 3.

At time T3, when the coil current reaches the current value I2, the drive circuit 41 decreases the coil voltage to the voltage value V1. The drive circuit 41 holds the coil voltage at the voltage value V1 in the 3 rd period T3T 4. The drive circuit 41 applies a coil voltage signal of a voltage value V1 and a duty ratio A3 to the coil 32 in the third period T3T 4. Duty cycle A3 is greater than duty cycle a 1. The duty cycle a3 is, for example, 100%. However, the duty cycle a3 may also be less than 100%.

In the 3 rd period T3T 4, the coil current is held at the current value I2. Current value I2 is greater than current value I1. In this way, in the 2 nd period T2T 3 and the 3 rd period T3T 4, the coil current rapidly rises and is held at the high current value I2, and therefore the pressing force of the movable contacts 16 and 17 against the fixed contacts 14 and 15 increases. Thus, in the 2 nd period T2T 3 and the third period T3T 4, the bounce of the movable contacts 16 and 17 is reduced.

When a predetermined time has elapsed from time T3, the drive circuit 41 applies the coil voltage signal having the voltage value V1 and the duty ratio a4 to the coil 32 in the fourth period after time T4. The duty cycle a4 is less than 100%. Duty cycle a4 is less than duty cycle a 1. This reduces power consumption while the contact 1417 is held in the closed state.

In the electromagnetic relay 1 according to the present embodiment described above, in the 1 st period T1T 2, a current is caused to flow through the coil 32 at a slower rising speed than in the 2 nd period T2T 3. Therefore, the collision energy of the contact 1417 can be reduced. Thus, bounce of the contacts is reduced. In the 2 nd period T2T 3, a current is caused to flow through the coil 32 at a higher rising speed than in the 1 st period T1T 2. Therefore, the pressing force of the movable contacts 16 and 17 against the fixed contacts 14 and 15 increases. Thus, the bounce of the contacts is further reduced. In addition, the collision noise at the time of contact of the contacts can be reduced.

While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

In the above embodiment, the driving device 4 pushes out the driving shaft 19 from the driving device 4 side, thereby moving the movable contact piece 13 in the closing direction Z1. Further, the drive device 4 pulls the drive shaft 19 into the drive device 4 side, thereby moving the movable contact piece 13 in the opening direction Z2. However, the operation direction of the drive shaft 19 for opening and closing the contacts may be opposite to that of the above-described embodiment. That is, the drive device 4 may pull the drive shaft 19 into the drive device 4 side to move the movable contact piece 13 in the closing direction Z1. The driving device 4 may push out the driving shaft 19 from the driving device 4 side to move the movable contact piece 13 in the opening direction Z2. That is, the closing direction Z1 and the opening direction Z2 may be opposite to the above embodiment.

The shape or arrangement of the 1 st fixed terminal 11, the 2 nd fixed terminal 12, or the movable contact piece 13 may be changed. For example, as shown in fig. 5, the 1 st and 2 nd external terminal portions 22 and 24 may protrude from the housing 3 in the left-right direction. Or the 1 st and 2 nd external terminal portions 22 and 24 may protrude from the housing 3 in the front-rear direction. The shape and arrangement of the movable core 31, the coil 32, the fixed core 33, and the yoke 34 may be changed. The shape and arrangement of the 1 st fixed contact 14, the 2 nd fixed contact 15, the 1 st movable contact 16, and the 2 nd movable contact 17 may be changed.

The 1 st fixed contact 14 may be separate from the 1 st fixed terminal 11 or may be integrated therewith. The 2 nd fixed contact 15 may be separate from the 2 nd fixed terminal 12 or may be integrated. The 1 st movable contact 16 may be separate from the movable contact piece 13 or may be integrated. The 2 nd movable contact 17 may be separate from the movable contact piece 13 or may be integrated.

The configuration of the drive circuit 41 is not limited to the above embodiment, and may be modified. The drive circuit 41 may be a known circuit for performing PWM control. The contact voltage detecting unit 48 may also be omitted. In the above embodiment, the drive circuit 41 changes the rising speed of the coil current from the 1 st rising speed to the 2 nd rising speed at the time when the contact of the contact 1417 is detected. However, the drive circuit 41 may measure the elapsed time from the time T1, and change the rising speed of the coil current from the 1 st rising speed to the 2 nd rising speed when a predetermined time has elapsed from the time T1. In this case, the 1 st period may be a period from time T1 to before the contact time of the contact 1417.

Industrial applicability

According to the present invention, in the electromagnetic relay, the bounce at the time of contact of the contact can be reduced.