Patent Application
20220293378
This application claims priority to Japanese Patent Application No. 2021-041697, filed Mar. 15, 2021. The contents of that application are incorporated by reference herein in their entirety.
The present invention relates to an electromagnetic relay.
The electromagnetic relay disclosed in Japanese Unexamined Patent Application Publication 2012-104360 includes a magnet for blocking an arc generated at a contact. The arc is extended in the arc extinguishing space in the contact case by the Lorentz force due to the magnetic force of the magnet. The magnet is located on the outside of the contact case made of an insulating material to prevent the arc from continuing through the magnets during interruption and to protect against the arc.
In the electromagnetic relay in Japanese Unexamined Patent Application Publication No. 2012-104360, in order to increase the magnetic flux density in the vicinity of the contact, it is necessary to use a magnet having a strong magnetic force, which may increase the manufacturing cost of the electromagnetic relay. Further, when the magnet is disposed near the contact, the manufacturing cost of the electromagnetic relay may increase even when a member for protecting the magnet from the arc is separately provided or when a member for holding the magnet is separately provided. For example, in the electromagnetic relay disclosed in Chinese Utility Model No. 202013854, a sealing material is applied to hold the magnet on the outside of the base, which increases the manufacturing cost.
An object of the present invention is to suppress an increase in manufacturing cost in an electromagnetic relay.
The electromagnetic relay according to one aspect of the present invention includes a first fixed terminal, a base, and a magnet. The first fixed terminal includes a first fixed contact. The base holds the first fixed terminal. The base includes a magnet insertion hole disposed in a vicinity of the first fixed contact. The magnet insertion hole has an opening opened toward the first fixed terminal. The magnet is disposed in the magnet insertion hole and is prevented from coming off from the magnet insertion hole by the first fixing terminal.
In this electromagnetic relay, the magnet is prevented from coming off from the magnet insertion hole by the first fixed terminal. That is, since the first fixed terminal is disposed so as to cover at least a part of the magnet insertion hole, it is possible to suppress the magnet from being affected by an arc by the first fixed terminal. As a result, it is possible to suppress an increase in the manufacturing cost of the electromagnetic relay as compared with the case where a member for protecting the magnet from the arc or a member for holding the magnet are separately provided. Further, since the magnet can be disposed in the vicinity of the first fixed contact, the magnetic flux density can be efficiently increased in the vicinity of the first fixed contact. As a result, it becomes possible to select a magnet having a low magnetic force, so that it is possible to further suppress an increase in the manufacturing cost of the electromagnetic relay.
The first fixed terminal may cover a whole of the opening of the magnet insertion hole. In this case, the magnet can be further suppressed from being affected by the arc.
The magnet may be disposed apart from the first fixed terminal. In this case, it is possible to suppress the first fixed terminal from interfering with the magnet, so that, for example, a variation in the height of the first fixed contact can be avoided.
The first fixed terminal may further include a contact support portion configured to support the first fixed contact, and a first extending portion extending at an angle from the contact support portion and protruding outward from the base. In this case, for example, when the arc is stretched in the direction from the contact support portion toward the first extension portion, the first extension portion can also serve as an arc horn for stretching the arc.
The first fixed terminal may further include a second extending portion that is connected to the contact support portion and faces the first extending portion. The magnet insertion hole may be disposed between the first extending portion and the second extending portion. In this case, for example, in an electromagnetic relay in which the extension direction of the arc changes depending on the polarity, the first extending portion and the second extending portion can also serve as an arc horn for stretching the arc. Further, the magnet can be prevented from coming off from the magnet insertion hole by any of the first extending portion, the second extending portion, and the contact support portion.
The first fixed terminal may further include a contact support portion that supports the first fixed contact. The magnet insertion hole may be opened toward the contact support portion. In this case, the magnetic flux density can be efficiently increased in the vicinity of the first fixed contact.
The first fixed contact may include a caulked portion fixed by being caulked to the first fixed terminal. The caulked portion may be disposed in the magnet insertion hole. In this case, interference of the caulked portion with the base due to the magnet insertion hole can be avoided. That is, the magnet insertion hole can be used as a space for releasing the caulked portion.
The electromagnetic relay may further include a second fixed terminal and a movable contact piece. The second fixed terminal may include a second fixed contact and may be disposed apart from the first fixed terminal. The movable contact piece may include a first movable contact facing the first fixed contact and a second movable contact facing the second fixed contact. In this case, in the electromagnetic relay including the first fixed terminal and the second fixed terminal, it is possible to suppress an increase in the manufacturing cost of the electromagnetic relay.
Hereinbelow, an embodiment of an electromagnetic relay according to one aspect of the present invention will be described with reference to the drawings. Note that in each drawing, the X1 direction will be described as the left direction, the X2 direction as the right direction, the Y1 direction as the front direction, the Y2 direction as the rear direction, the Z2 direction as the upward direction, and the Z1 direction as the downward direction. It should be noted that these directions are defined for convenience of explanation, and do not limit the arrangement direction of the electromagnetic relay.
As illustrated in
The terminal support portions 22a and 22b are formed so as to protrude upward from the bottom portion 21. The terminal support portion 22a is disposed apart from the terminal support portion 22b in the left-right direction. The upper surfaces of the terminal support portions 22a and 22b include flat surfaces orthogonal to each other in the up-down direction.
The magnet insertion hole 23a is provided in the terminal support portion 22a. The magnet insertion hole 23a opens upward. The magnet insertion hole 23a is formed so as to be recessed downward on the upper surface of the terminal support portion 22a. The magnet insertion hole 23a is covered with the terminal support portion 22a in the left-right direction, the front-back direction, and below. The magnet insertion hole 23b is provided in the terminal support portion 22b. The magnet insertion hole 23b opens upward. The magnet insertion hole 23b is formed so as to be recessed downward on the upper surface of the terminal support portion 22b.
The contact device 3 includes a first fixed terminal 6, a second fixed terminal 7, a movable contact piece 8, a movable member 9, and a contact spring 10. The first fixed terminal 6, the second fixed terminal 7, and the movable contact piece 8 are plate-shaped terminals and are made of a conductive material such as copper.
The first fixed terminal 6 and the second fixed terminal 7 have a U-shaped cross section, and when viewed from the left-right direction have a shape bent in a U-shape. The first fixed terminal 6 and the second fixed terminal 7 are held by the base 2. The first fixed terminal 6 and the second fixed terminal 7 are fixed by being press-fitted into the base 2, for example.
The first fixed terminal 6 includes a first fixed contact 6a, a contact support portion 6b, a first extending portion 6c, a second extending portion 6d, a pair of external connection portions 6e. The first fixed contact 6a is disposed on the contact support portion 6b. The first fixed contact 6a includes a caulked portion 6f that is fixed by being caulked to the first fixed terminal 6. The caulked portion 6f protrudes downward from the contact support portion 6b. The caulked portion 6f is disposed in the magnet insertion hole 23a.
The contact support portion 6b is supported by the upper surface of the terminal support portion 22a. The contact support portion 6b extends in a direction orthogonal to the up-down direction. The contact support portion 6b supports the first fixed contact 6a. The first fixed contact 6a is fixed by being caulked to the contact support portion 6b. The first fixed contact 6a may be integrated with the first fixed terminal 6, and caulked portion 6f may be omitted.
The first extending portion 6c and the second extending portion 6d are fixed by being press-fitted into the bottom portion 21 of the base 2. The first extending portion 6c is connected to the contact support portion 6b and protrudes outward from the base 2. The first extending portion 6c bends downward from the front end of the contact support portion 6b and protrudes downward from the bottom portion 21 of the base 2. The first extending portion 6c is in contact with the front surface of the terminal support portion 22a. The second extending portion 6d faces the first extending portion 6c in the front-rear direction. The second extending portion 6d is connected to the contact support portion 6b and protrudes outward from the base 2. The second extending portion 6d bends downward from the rear end of the contact support portion 6b and protrudes downward from the bottom portion 21 of the base 2. The second extending portion 6d is in contact with the rear surface of the terminal support portion 22a. The pair of external connection portions 6e are disposed at the lower end of the first extending portion 6c and the lower end of the second extending portion 6d, and are electrically connected to an external device (not shown).
The second fixed terminal 7 is disposed apart from the first fixed terminal 6 in the left-right direction. The second fixed terminal 7 has the same shape as the first fixed terminal 6. The second fixed terminal 7 includes a second fixed contact 7a, a contact support portion 7b, a first extending portion 7c, a second extending portion 7d, a pair of external connecting portions 7e, and a caulked portion 7f. Since each configuration of the second fixed terminal 7 is the same as each configuration of the first fixed terminal 6, the description thereof will be omitted.
The movable contact piece 8 extends in the left-right direction. The longitudinal direction of the movable contact piece 8 coincides with the left-right direction. The movable contact piece 8 is disposed above the first fixed terminal 6 and the second fixed terminal 7. The movable contact piece 8 includes a first movable contact 8a and a second movable contact 8b. The first movable contact 8a faces the first fixed contact 6a in the up-down direction and can make contact with the first fixed contact 6a. The second movable contact 8b faces the second fixed contact 7a in the up-down direction and can make contact with the second fixed contact 7a. In the present embodiment, the first movable contact 8a and the second movable contact 8b are fixed by being caulked to the movable contact piece 8, but the first movable contact 8a and the second movable contact 8b may be integrated with the movable contact piece 8.
The movable contact piece 8 is movable in a contact direction in which the first movable contact 8a approaches the first fixed contact 6a and an opening direction in which the first movable contact 8a separates from the first fixed contact 6a. In the present embodiment, the movable contact piece 8 is movable in the up-down direction. The movable contact piece 8 is connected to the movable member 9. The movable contact piece 8 is relatively movable with respect to the movable member 9 in the up-down direction.
The movable member 9 extends in the up-down direction. The movable member 9 is disposed at the center of the movable contact piece 8 in the left-right direction. The movable member 9 is made of an insulating material such as resin.
The upper end of the movable member 9 is connected to the drive device 4. The movable member 9 is movable in the up-down direction.
The contact spring 10 is a coil spring and urges the movable contact piece 8 in the contact direction (downward in the present embodiment). The contact spring 10 is housed inside the movable member 9.
The drive device 4 is disposed behind the contact device 3. The drive device 4 moves the movable contact piece 8 in the up-down direction via the movable member 9. The drive device 4 includes a coil 4a, a spool 4b, a fixed iron core 4c, a yoke 4d, a movable iron piece 4e, a hinge spring 4f, and a return spring 4g.
The coil 4a is wound around the outer circumference of the spool 4b. The spool 4b extends in the up-down direction. The fixed iron core 4c is disposed on the inner peripheral portion of the spool 4b. The yoke 4d is disposed so as to cover the rear of the coil 4a. The yoke 4d is substantially L-shaped when viewed from the left-right direction. The yoke 4d is connected to the lower end of the fixed iron core 4c.
The movable iron piece 4e is rotatably supported by the yoke 4d via the hinge spring 4f. The movable iron piece 4e rotates with the upper end of the yoke 4d as a fulcrum. The right end of the movable iron piece 4e is disposed above the movable member 9. The movable iron piece 4e is disposed above the fixed iron core 4c. The hinge spring 4f urges the movable iron piece 4e in a direction away from the fixed iron core 4c. The return spring 4g is disposed between the bottom portion 21 of the base 2 and the movable member 9. The return spring 4g urges the movable member 9 in the opening direction (upward in the present embodiment).
Next, the operation of the electromagnetic relay 1 will be described. In a state in which no voltage is applied to the coil 4a, the movable member 9 is pressed in the opening direction by the elastic force of the hinge spring 4f and the return spring 4g. Therefore, the first movable contact 8a is separated from the first fixed contact 6a, and the second movable contact 8b is separated from the second fixed contact 7a.
When a voltage is applied to the coil 4a whereby the drive device 4 is excited, the movable iron piece 4e is attracted to the fixed iron core 4c and rotates, and the movable member 9 is pressed in the contact direction by the movable iron piece 4e. As a result, the movable member 9 moves in the contact direction against the elastic forces of the hinge spring 4f and the return spring 4g. As the movable member 9 moves in the contact direction, the contact spring 10 moves in the contact direction. As a result, the movable contact piece 8 moves in the contact direction, such that the first movable contact 8a comes into contact with the first fixed contact 6a, and the second movable contact 8b comes into contact with the second fixed contact 7a. When the application of the voltage to the coil 4a is stopped, the movable member 9 moves in the opening direction by the elastic force of the hinge spring 4f and the return spring 4g.
The magnet 30a is disposed in the magnet insertion hole 23a. The magnet 30a is prevented from coming off from the magnet insertion hole 23a by the first fixed terminal 6. Here, the magnet insertion hole 23a is provided in the vicinity of the first fixed contact 6a and opens toward the first fixed terminal 6. The magnet insertion hole 23a is disposed between the first extending portion 6c and the second extending portion 6d. In the present embodiment, the magnet insertion hole 23a is provided in the lower part of the contact support portion 6b and opens toward the contact support portion 6b. The first fixed terminal 6 covers the entire magnet insertion hole 23a. The magnet insertion hole 23a is sealed by the contact support portion 6b of the first fixed terminal 6. The magnet 30a may be lightly press-fitted into the magnet insertion hole 23a, for example. In that case, it is possible to prevent the position of the magnet 30a from fluctuating depending on the mounting direction of the electromagnetic relay 1 and affecting the breaking performance.
The magnet 30a is disposed below the first fixed contact 6a and overlaps with the first fixed contact 6a when viewed from the up-down direction. The magnet 30a is disposed apart from the first fixed terminal 6 and is not in contact with the first fixed terminal 6. The magnet 30a is disposed apart from the caulked portion 6f in the up-down direction.
The magnet 30a is disposed so that the magnetic flux of the magnet 30a flows in a direction intersecting the up-down direction between the contacts of the first fixed contact 6a and the first movable contact 8a. For example, the magnet 30a is disposed so that the north and the south pole face in the left-right direction. The magnet 30a may be disposed so that the north pole and the south pole face in the front-rear direction.
The magnet 30b has the same configuration as the magnet 30a except that the arrangement is different from that of the magnet 30a. The magnet 30b is disposed in the magnet insertion hole 23b. The magnet 30b is prevented from coming off from the magnet insertion hole 23b by the second fixed terminal 7. The magnet insertion hole 23b is provided in the vicinity of the second fixed contact 7a and opens toward the second fixed terminal 7. The magnet insertion hole 23b is disposed between the first extending portion 7c and the second extending portion 7d. In the present embodiment, the magnet insertion hole 23b is provided in the lower part of the contact support portion 7b and opens toward the contact support portion 7b. The second fixed terminal 7 covers the entire magnet insertion hole 23b. The magnet insertion hole 23b is sealed by the contact support portion 7b of the second fixed terminal 7.
In this electromagnetic relay 1, the magnet 30a is prevented from coming off from the magnet insertion hole 23a by the first fixed terminal 6. That is, since the first fixed terminal 6 is disposed so as to cover at least a part of the magnet insertion hole 23a, it is possible to suppress the magnet 30a from being affected by an arc generated between the first fixed contact 6a and the first movable contact 8a by the first fixed terminal 6. As a result, it is possible to suppress an increase in the manufacturing cost of the electromagnetic relay 1 as compared with the case where a member for protecting the magnet 30a from the arc or a member for holding the magnet 30a are separately provided. Further, since the magnet 30a can be disposed in the vicinity of the first fixed contact 6a, the magnetic flux density can be efficiently increased in the vicinity of the first fixed contact 6a. As a result, it becomes possible to select a ferrite magnet that is cheaper than the neodymium magnet in the magnet 30a, so that it is possible to further suppress an increase in the manufacturing cost of the electromagnetic relay 1. With respect to the magnet 30b, the magnetic flux density can be efficiently increased in the vicinity of the second fixed contact 7a, and the same effect as that of the magnet 30a can be obtained.
In the present embodiment, since the entire magnet insertion hole 23a is covered by the first fixed terminal 6, the magnet 30a can be further suppressed from being affected by the arc.
Further, since the magnet 30a is disposed below the first fixed contact 6a, a strong magnetic flux is generated below the first fixed contact 6a, and the arc is easily extended downward. Therefore, the first extending portion 6c and the second extending portion 6d can also serve as an arc horn for extending the arc. Further, by disposing the caulked portion 6f in the magnet insertion hole 23a, the magnet insertion hole 23a can be used as a space for releasing the caulked portion 6f.
While preferred embodiment of the electromagnetic relay according to one aspect of the present invention have been described above, it should be understood that the present invention is not limited to the above embodiment, and various changes can be made without departing from the gist of the invention. For example, the configuration of the contact device 3 or the drive device 4 may be changed.
In the above embodiment, the first fixed terminal 6 has a U-shaped cross section, but as schematically shown in
In the above embodiment, the magnet insertion hole 23a is open toward the contact support portion 6b, but the magnet insertion hole 23a may be open toward the first extending portion 6c or the second extending portion 6d. That is, the magnet 30a may be prevented from coming off from the magnet insertion hole 23a by the first extending portion 6c or the second extending portion 6d. Further, in a case of the configuration that does not stretch the arc toward the magnet insertion hole 23a, the first fixed terminal 6 does not need to cover the entire magnet insertion hole 23a.
In the above embodiment, the first fixed contact 6a and the first movable contact 8a are disposed so as to face each other in the up-down direction. However, as schematically shown in
The first fixed terminal 106 shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-041697 | Mar 2021 | JP | national |
