Relay

Abstract

To provide a technique capable of suppressing vibration of a relay.SOLUTION: A relay comprises: a stationary contact point; a movable contact which is disposed at a lower side with respect to the stationary contact point and moves back and forth in a vertical direction with respect to the stationary contact point; a pair of yokes disposed oppositely in the vertical direction while holding the movable contact therebetween and adjacent to each other via a predetermined clearance at both sides in a horizontal direction of the movable contact; a pair of permanent magnets disposed oppositely in the horizontal direction while holding the pair of yokes therebetween; and a coil for excitation, which is disposed at a lower side with respect to the pair of yokes, for moving the movable contact back and forth. With respect to the vertical direction, center positions of the pair of permanent magnets are substantially coincident with a position of the predetermined clearance which is formed between the pair of yokes.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a relay that cuts off a current path. [Background technology]

[0002] Patent Document 1 discloses a relay including a fixed contact, a movable contact, and a pair of magnets. The pair of magnets are arranged such that the north pole of one magnet faces the south pole of the other magnet. In this configuration, when a current flows through the movable contact, an electromagnetic force is generated in the direction from the movable contact side to the fixed contact side, thereby suppressing vibrations generated in the relay.

[0003] Moreover, Patent Document 2 discloses a relay including a fixed contact, a movable contactor having a movable contact, and a pair of yokes arranged to sandwich the movable contactor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-162710 A [Patent Document 2] JP 2012-199112 A Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, when a current flows through a relay opening / closing coil to open or close a relay (for example, to close the relay), a magnetic field (hereinafter sometimes referred to as a "coil magnetic field") is generated by the current. The electromagnetic force generated between the pair of yokes depends not only on the magnetic field generated by the pair of magnets, but also on the coil magnetic field. The electromagnetic force generated between the pair of yokes causes vibrations and the like in the relay.

[0006] In Patent Documents 1 and 2, the electromagnetic force generated between the pair of yokes is not taken into consideration that the magnetic field of the pair of magnets and a magnetic field other than the magnetic field of the pair of magnets (for example, the above-mentioned coil magnetic field) may affect each other. This specification provides a technology that can suppress vibration of a relay. [Means for solving the problem]

[0007] The relay disclosed in this specification comprises a fixed contact, a movable contactor arranged below the fixed contact and moving back and forth in an up-down direction relative to the fixed contact, a pair of yokes arranged opposite each other in the up-down direction with the movable contactor in between, and on both sides of the movable contactor in the left-right direction, adjacent to each other with a predetermined gap therebetween, a pair of permanent magnets arranged opposite each other in the left-right direction with the pair of yokes in between, and an excitation winding arranged below the pair of yokes for moving the movable contactor back and forth, and with respect to the up-down direction, the central position of each of the pair of permanent magnets approximately coincides with the position of the predetermined gap formed between the pair of yokes.

[0008] In this specification, terms such as "upper", "lower", and "vertical" are expedient expressions for indicating relative positional relationships within a relay, and do not limit the orientation or posture of the relay when in use or during manufacture. Similarly, terms such as "left", "right", and "horizontal" are expedient expressions for indicating a direction perpendicular to the above-mentioned vertical direction, and do not limit the orientation or posture of the relay when in use or during manufacture.

[0009] The electromagnetic force generated between the pair of yokes is less susceptible to the horizontal magnetic field, but is more susceptible to the vertical magnetic field. According to the above configuration, the vertical center positions of the pair of permanent magnets approximately coincide with the position of a predetermined gap formed between the pair of yokes. Therefore, the vertical component of the magnetic field formed by the pair of permanent magnets between the pair of yokes is reduced. Therefore, the vertical component of the magnetic field formed at the position between the pair of yokes is prevented from becoming excessively large. In other words, the electromagnetic force between the pair of yokes is prevented from becoming excessively large. Therefore, vibration of the relay is suppressed.

[0010] In an embodiment of the present technology, in addition to the above configuration, the arrangement of the magnetic poles of the pair of permanent magnets may be determined according to the positional relationship between the center position of the pair of permanent magnets in the up-down direction and the position of the predetermined gap formed between the pair of yokes, and the direction of the magnetic field generated by the excitation winding. With such a configuration, it is possible to more effectively suppress vibration of the relay. [Brief description of the drawings]

[0011] [Figure 1] 1 shows a longitudinal cross-sectional view of a relay. [Diagram 2] 1 shows a cross-sectional view of a relay. [Diagram 3] 3(a) to 3(f) show the directions of magnetic fields generated according to the arrangement of the permanent magnets and excitation windings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] This specification discloses a relay 10. The relay 10 is mounted on, for example, an electric vehicle having a battery, a drive motor, and a power conversion device that converts the output power of the battery into drive power for the motor. The relay 10 is provided between the battery and the power conversion device. When the switch of the electric vehicle is turned on, the relay 10 closes, and the battery, the power conversion device, and the motor are electrically connected to each other. When the switch of the electric vehicle is turned off, the relay 10 opens, and the battery, the power conversion device, and the motor are electrically isolated from each other.

[0013] 1, the relay 10 includes a contact device 100 and an electromagnet device 200. In other words, the relay 10 is a so-called electromagnetic relay.

[0014] The contact device 100 includes a fixed terminal 110, a movable contactor 120, an upper yoke 130, a lower yoke 140, and a spring 150. The fixed terminal 110 has a fixed contact 112 at its tip. The fixed contact 112, the movable contactor 120, the upper yoke 130, and the lower yoke 140 are housed in a case 102.

[0015] 1 (i.e., downward) relative to the fixed terminal 110. The movable contactor 120 advances and retreats relative to the fixed contact 112. That is, the movable contactor 120 advances and retreats in the Z-axis direction (i.e., up and down direction). A movable contact (not shown) is provided on the upper surface of the movable contactor 120 at a position facing the fixed contact 112. When the movable contactor 120 moves upward and the fixed contact 112 comes into contact with the movable contact, the relay 10 is closed (i.e., conductive).

[0016] An upper yoke 130 and a lower yoke 140 are provided above and below the movable contactor 120. Specifically, the upper yoke 130 faces the upper surface of the movable contactor 120 (i.e., the surface on which the movable contact is provided). The lower yoke 140 faces the lower surface of the movable contactor 120 (i.e., the surface opposite to the surface on which the movable contact is provided). That is, the upper yoke 130 and the lower yoke 140 are disposed opposite each other in the upper and lower direction (i.e., the Z-axis direction) with the movable contactor 120 in between. A spring 150 is connected to the lower surface of the lower yoke 140.

[0017] 2, the upper yoke 130 and the lower yoke 140 are adjacent to each other on both sides in the Y-axis direction (hereinafter referred to as the "left-right direction") of the movable contact 120. Specifically, in this embodiment, the lower yoke 140 protrudes toward the upper yoke 130 on both sides in the left-right direction of the movable contact 120. On both sides in the left-right direction of the movable contact 120, the upper yoke 130 and the lower yoke 140 are adjacent to each other with a gap g therebetween.

[0018] Further, permanent magnets 160 are housed in the case 102 at both ends in the left-right direction. The permanent magnets 160 are arranged facing each other in the left-right direction, sandwiching the upper yoke 130 and the lower yoke 140 therebetween. They are provided to extinguish an arc that occurs when the movable contact and the fixed contact 112 come into contact with each other. A more specific arrangement of the permanent magnets 160 will be described later with reference to FIG. 3.

[0019] As shown in Fig. 1, the electromagnetic device 200 includes an excitation winding 204, a fixed core 206, and a movable core 208. The excitation winding 204, the fixed core 206, and the movable core 208 are housed in a case 202. In Fig. 1, the illustration of a portion of the configuration of the electromagnetic device 200 is omitted, and detailed description thereof will be omitted.

[0020] The fixed core 206 and the movable core 208 form a magnetic path through which the magnetic flux generated by the excitation winding 204 passes. When a current flows through the excitation winding 204, the fixed core 206 and the movable core 208 have opposite polarities, and the movable core 208 moves upward.

[0021] When a current flows through the excitation winding 204, a magnetic field is generated around the excitation winding 204. At this time, depending on the configuration such as the arrangement of the excitation winding 204, a magnetic field is formed that is directed from the bottom to the top, or from the top to the bottom, as shown in FIG.

[0022] The upper end of the movable core 208 faces the lower yoke 140 via the spring 150. When a current flows through the excitation winding 204 and the movable core 208 moves upward, the spring 150 is pressurized upward. When the spring 150 is pressurized upward, the lower yoke 140 moves upward. When the lower yoke 140 moves upward, the movable contact of the movable contactor 120 comes into contact with the fixed contact 112 (i.e., the relay 10 is closed). As a result, a current flows between the two fixed terminals 110, 110 through the movable contactor 120. In other words, a state is created in which power is supplied from the battery to the power conversion device.

[0023] Furthermore, when the relay 10 is closed and a current flows through the movable contact 120, a magnetic flux passes through the upper yoke 130 and the lower yoke 140. Therefore, the upper yoke 130 and the lower yoke 140 are magnetized, and a force that attracts the upper yoke 130 and the lower yoke 140 to each other is generated.

[0024] On the other hand, when a current flows through the movable contactor 120, an electromagnetic force is generated between the upper yoke 130 and the lower yoke 140 due to the current and the magnetic field around the yokes 130 and 140. If the sum of the pressure force of the spring 150 and the force with which the upper yoke 130 and the lower yoke 140 attract each other is greater than the above-mentioned electromagnetic force, the movable contactor 120 does not separate from the fixed contact 112. Therefore, the contact between the movable contactor 120 and the fixed contact 112 can be made more reliable than when the yokes 130 and 140 are not provided.

[0025] As described above, the relay 10 of the present embodiment is mounted on an electric vehicle equipped with a power converter. The electric vehicle runs when the relay 10 is closed. When the electric vehicle runs, the output power of the battery is converted by the power converter and supplied to the motor. The power converter converts the output power of the battery into driving power for the motor by the operation of the switching element. A ripple current that varies depending on the frequency of the switching element flows through the relay 10 (i.e., the movable contact 120). This varying ripple current and the magnetic field around the yokes 130 and 140 generate a varying electromagnetic force between the upper yoke 130 and the lower yoke 140. This electromagnetic force depends on the magnitude of the current flowing through the movable contact 120 and the magnitude of the magnetic field between the upper yoke 130 and the lower yoke 140.

[0026] In the configuration of this embodiment, a magnetic field is formed between the upper yoke 130 and the lower yoke 140, which is influenced by the magnetic field formed by the permanent magnet 160 and the magnetic field generated by the current flowing through the excitation winding 204. When a fluctuating ripple current flows through the movable contact 120, this magnetic field generates an electromagnetic force between the upper yoke 130 and the lower yoke 140. In particular, the electromagnetic force generated between the upper yoke 130 and the lower yoke 140 is less susceptible to the magnetic field in the left-right direction (i.e., the Y-axis direction) and more susceptible to the magnetic field in the up-down direction (i.e., the Z-axis direction). Therefore, for example, if the magnetic field in the up-down direction is relatively large, the electromagnetic force generated between the upper yoke 130 and the lower yoke 140 becomes large. If the electromagnetic force becomes large, the vibration of the relay 10 becomes large.

[0027] 2 and 3, in the relay 10 of this embodiment, the center positions of the pair of permanent magnets 160 in the vertical direction are approximately aligned with the position of the gap g formed between the upper yoke 130 and the lower yoke 140. If these positions are approximately aligned, the vertical component of the magnetic field formed by the permanent magnet 160 is likely to be small at the position between the upper yoke 130 and the lower yoke 140, regardless of the orientation of the magnetic poles of the permanent magnet 160. The reason for this will be explained below with reference to FIG. 3. In each case of FIG. 3, the center positions of the pair of permanent magnets 160 in the vertical direction are approximately aligned with the position of the gap g formed between the upper yoke 130 and the lower yoke 140, but the former is slightly higher.

[0028] First, as shown in FIG. 3(a) and FIG. 3(b), a case where the N pole and S pole of a pair of permanent magnets 160 face each other will be described. FIG. 3(a) shows a case where the magnetic field formed by the excitation winding 204 faces upward, and FIG. 3(b) shows a case where the magnetic field formed by the excitation winding 204 faces downward. In this embodiment, a situation where the S pole of the left permanent magnet 160 faces the N pole of the right permanent magnet 160 will be described. In this case, the magnetic field formed by the pair of permanent magnets 160 is in a direction from the right permanent magnet 160 to the left permanent magnet 160. That is, a magnetic field in the left-right direction is formed by the pair of permanent magnets 160. Therefore, as shown in FIG. 3, a magnetic field in the left-right direction is also formed by the permanent magnet 160 at a position between the upper yoke 130 and the lower yoke 140, and the vertical component is small.

[0029] Next, as shown in FIG. 3(c) and FIG. 3(d), a case where the N poles of a pair of permanent magnets 160 face each other will be described. FIG. 3(c) shows a case where the magnetic field formed by the excitation winding 204 faces upward, and FIG. 3(d) shows a case where the magnetic field formed by the excitation winding 204 faces downward. First, for the N pole of the left permanent magnet 160, a magnetic field is generated from the center position in the vertical direction to the right. A magnetic field containing an upward component is generated above the center position, and a magnetic field containing a downward component is generated below the center position. Similarly, for the N pole of the right permanent magnet 160, a magnetic field is generated from the center position in the vertical direction to the left, a magnetic field containing an upward component is generated above the center position, and a magnetic field containing a downward component is generated below the center position. In this embodiment, as shown in FIG. 3(c) and FIG. 3(d), since the center position of the permanent magnet 160 is located above the gap g, a magnetic field containing a downward component is generated at the position between the upper yoke 130 and the lower yoke 140. In particular, in the magnetic field generated above (or below) the central position, the upward (or downward) component becomes larger as the distance from the central position increases. Therefore, in terms of the vertical direction, if the central positions of the pair of permanent magnets 160 and the position of the gap g between the upper yoke 130 and the lower yoke 140 approximately coincide with each other, the vertical component of the magnetic field generated by the permanent magnet 160 at the position between the upper yoke 130 and the lower yoke 140 tends to become smaller.

[0030] Next, as shown in FIG. 3(e) and FIG. 3(f), a case where the S poles of a pair of permanent magnets 160 face each other will be described. FIG. 3(e) shows a case where the magnetic field formed by the excitation winding 204 faces upward, and FIG. 3(f) shows a case where the magnetic field formed by the excitation winding 204 faces downward. First, for the S pole of the left permanent magnet 160, a magnetic field is generated from the right direction at the center position in the vertical direction. A magnetic field containing a downward component is generated above the center position, and a magnetic field containing an upward component is generated below the center position. Similarly, for the S pole of the right permanent magnet 160, a magnetic field is generated from the left direction at the center position in the vertical direction, a magnetic field containing a downward component is generated above the center position, and a magnetic field containing an upward component is generated below the center position. In this embodiment, as shown in FIG. 3(e) and FIG. 3(f), since the center position of the permanent magnet 160 is located above the gap g, a magnetic field containing an upward component is generated at the position between the upper yoke 130 and the lower yoke 140. In particular, in the magnetic field generated above (or below) the central position, the upward (or downward) component becomes larger as the distance from the central position increases. Therefore, in terms of the vertical direction, if the central positions of the pair of permanent magnets 160 and the position of the gap g between the upper yoke 130 and the lower yoke 140 approximately coincide with each other, the vertical component of the magnetic field generated by the permanent magnet 160 at the position between the upper yoke 130 and the lower yoke 140 tends to become smaller.

[0031] As described above, when the electromagnetic force generated between the upper yoke 130 and the lower yoke 140 increases, the vibration of the relay 10 increases. In this regard, according to the configuration of this embodiment, the center positions of the pair of permanent magnets 160 in the vertical direction are approximately aligned with the position of the gap g formed between the upper yoke 130 and the lower yoke 140. Therefore, as described above, the vertical component of the magnetic field formed by the pair of permanent magnets 160 at the position between the upper yoke 130 and the lower yoke 140 is reduced. Therefore, the vertical component of the magnetic field (i.e., the magnetic field formed by the pair of permanent magnets 160 and the magnetic field formed by the excitation winding 204) formed at the position between the upper yoke 130 and the lower yoke 140 is suppressed from increasing. In other words, the electromagnetic force between the upper yoke 130 and the lower yoke 140 is suppressed from becoming excessively large. Therefore, the vibration of the relay 10 is suppressed.

[0032] Also, for example, in the example shown in Fig. 3(d), the magnetic field generated by the permanent magnet 160 and the magnetic field generated by the excitation winding 204 are both directed downward. Therefore, these magnetic fields affect each other, and the electromagnetic force at the position between the upper yoke 130 and the lower yoke 140 becomes large. Similarly, in the example shown in Fig. 3(e), the electromagnetic force at the position between the upper yoke 130 and the lower yoke 140 becomes large. In such a case, the vibration of the relay 10 is likely to become large.

[0033] 3, the center positions of the pair of permanent magnets 160 in the vertical direction are located slightly above the position of the gap g formed between the upper yoke 130 and the lower yoke 140. On the other hand, when the center positions of the pair of permanent magnets 160 in the vertical direction are located slightly below the position of the gap g formed between the upper yoke 130 and the lower yoke 140, a magnetic field is formed between the upper yoke 130 and the lower yoke 140 in a downward direction when the N poles of the pair of permanent magnets 160 face each other, and in a upward direction when the S poles of the pair of permanent magnets 160 face each other. That is, a magnetic field is formed in a direction opposite to that in the cases of FIG. 3(c) to FIG. 3(f).

[0034] In this way, the direction of the magnetic field formed by the pair of permanent magnets 160 at a position between the upper yoke 130 and the lower yoke 140 depends on the positional relationship between the respective central positions of the pair of permanent magnets 160 in the up-down direction and the position of the gap g formed between the upper yoke 130 and the lower yoke 140. Therefore, by determining the arrangement of the magnetic poles of the permanent magnets 160 according to the above positional relationship and the direction of the magnetic field formed by the excitation winding 204, it is possible to more effectively suppress vibration of the relay 10.

[0035] 3(c), for example, the magnetic field formed by the pair of permanent magnets 160 and the magnetic field formed by the excitation winding 204 may weaken each other in the vertical direction. When these magnetic fields weaken each other, the electromagnetic force generated between the upper yoke 130 and the lower yoke 140 is reduced. This makes it possible to suppress vibration of the relay 10. However, if these magnetic fields are excessively weakened (e.g., canceled out), the adhesive force between the upper yoke 130 and the lower yoke 140 is weakened, which may cause an event in which the original purpose of the yoke cannot be achieved.

[0036] In this regard, as shown in Figures 3(a) and 3(b), when the north pole and south pole of a pair of permanent magnets 160 face each other, a uniform magnetic field is formed by the pair of permanent magnets 160 in the left-right direction. This magnetic field has a small vertical component. Therefore, in the vertical direction, it is difficult for the magnetic field to strengthen or weaken with the magnetic field formed by the excitation winding 204. Therefore, in such a case, it is possible to suppress vibration of the relay 10 while ensuring that the original purpose of the yoke is achieved.

[0037] The upper yoke 130 and the lower yoke 140 correspond to an example of a "pair of yokes" in the present technology. The gap g is an example of a "predetermined gap". [Explanation of symbols]

[0038] 10: relay, 100: contact device, 102: case, 110: fixed terminal, 112: fixed contact, 120: movable contact, 130: first yoke, 140: second yoke, 150: spring, 160: permanent magnet, 200: electromagnet device, 202: case, 204: excitation winding, 206: fixed core, 208: movable core, g: gap

Claims

[Claim 1] A fixed contact; A movable contactor is disposed below the fixed contact and moves up and down relative to the fixed contactor; a pair of yokes arranged opposite to each other in the up-down direction with the movable contact therebetween and adjacent to each other on both sides in the left-right direction of the movable contact with a predetermined gap therebetween; a pair of permanent magnets disposed opposite each other in the left-right direction with the pair of yokes interposed therebetween; an excitation winding disposed below the pair of yokes for moving the movable contact forward and backward; Equipped with a central position of each of the pair of permanent magnets in the vertical direction substantially coincides with a position of the predetermined gap formed between the pair of yokes.

Images