Patent Application
20060089050
1. Field of the Invention
The present invention relates to a relay having a fuse fixedly and directly connected to the relay.
2. Description of the Background Art
More and more electronic devices are mounted on vehicles to enhance fuel economy, anti-pollution measures, drivability, comfortableness in an interior space, etc. Thus, there has been an increase in the number of relays and fuses that are provided in a vehicle fuse box in order to control and protect electrical components. As such, the vehicle fuse boxes become increasingly larger and more complex.
A fuse protects a circuit against damage caused by a short circuit or overcurrent. The link in the fuse will melt and burn in half to stop excess current and further circuit damage. A relay is an electrically operated switch. It allows a small dash switch to control another circuit by remote control, whereby the control comes from a distant point in the circuit.
DE3209915 and U.S. Pat. No. 6,320,486 each disclose, with reference to
More importantly, because the melt plugable fuses 17 are inserted into the connector tabs 13, 15, heat is generated at contact points 19. In addition, because of current, the contact points 19 relax and degrade and therefore, even more heat is generated. Typically, approximately 1-1.5 watts of heat can be generated at each contact point.
For example, a typical vehicle fuse box 1 has approximately 20 relays and 20 fuses, whereby the fuses each have two contact points and the relays each have 4 contact points. Thus, there are 120 contact points that can generate 120-180 watts of heat. Because of the design of the relay 11 of the prior art, as shown in
Furthermore, the prior art devices are prone to operator error. For example, if an operator inserts a 40 amp fuse into relay that is rated for 20 amps, the wrongly inserted fuse provides no protection for the relay or the circuit elements associated therewith, which can thus lead to the relay igniting and burning.
It is therefore an object of the present invention to provide a universal protected relay that generates less heat and is able to be designed in a compact size. The relay includes a coil, a yoke having a first yoke leg and a second yoke leg, a first connector terminal being electrically connected to a first contact terminal, a second connector terminal being electrically connected to a second contact terminal via a movable contact, and a fuse having a first end portion and a second end portion. The first end portion and the second end portion of the fuse are fixedly and directly connected to the first contact terminal and the second contact terminal, respectively.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:
Referring to
The core 36 is connected to the first yoke leg 40. Coil terminals 44 are electrically connected to the coil 34 to energize the coil 34 by a remote switch (not shown). A connector terminal 46 is electrically connected to a contact terminal 52 and a connector terminal 48 is electrically connected to a movable contact terminal 50 that contacts a contact terminal 54 when the coil 34 is energized.
Between the contact terminals 52 and 54 a fuse 56 is arranged so that the fuse 56 is in series with the contact terminals 52 and 54, and thus in series with the connector terminals 46 and 48. The fuse 56 can be a melt type fuse, a resettable fuse, such as a polymeric PTC (Positive Temperature Coefficient) resettable fuse, a circuit breaker, a thermistor, or any type of circuit protecting device.
The fuse 56 shown in
Because the ends 60, 62 of the fuse 56 are directly and non-removably connected to the contact terminals 52, 54, no heat is generated. Whereas, as noted above, approximately 3 watts of heat are generated at the contact points of the plugable fuse of the prior art. Thus, the present invention significantly reduces the amount of heat being generated by the fuse linked relay 30. For example, in a vehicle having 20 fuse linked relays 30 in a fuse box, the amount of heat that is generated is approximately 80 watts. In contrast thereto, as previously noted, the fuse and relay combinations of the prior art generate 120-180 watts of heat or more.
In a preferred embodiment, the fuse linked relay 30 includes a thermally insulated wall 64 that is provided between the coil 34 and the fuse 56. The thermally insulated wall 64 reduces thermal derating effects between the coil 34 and the fuse 56. The thermally insulated wall 64 can be integrally molded with the housing 66, as shown in
In a further embodiment, the housing 66 can be made of a transparent material or can be formed so as to have a transparent window 70, which can be formed on the housing 66 by a two shot molding process or can be snap fit into the housing 66. The transparent window 70 is preferably provided, for example, on a top side 72 of the housing 66, so that the fuse link 58 can viewed to determine whether or not the fuse link 58 has been disconnected, e.g. blown. It is noted that the transparent window 70, or a plurality of transparent windows 70, can be provided anywhere on the housing 66, depending on the application of the fuse linked relay 30. In addition, the transparent window 70 can be smooth or textured and can also be colored to follow the standard color association of fuses. The housing 66 can also further include an aperture (not shown) for enabling access to manually reset the fuse 56.
The design of the fuse linked relay 30 of the present invention allows a small package that is smaller than standard micro-relay packages, while carrying up to 40 amps or more. The fuse linked relay 30 according to the present invention also eliminates connections in a fuse box of, for example, a vehicle, which thereby reduces the heat and temperature rise in the fuse box. As such, a vehicle fuse box can be reduced by up to 70% in comparison with a conventional vehicle fuse box. Furthermore, the relay according to the present invention can be rated for Pulse Width Modulation, which further reduces the temperature rise in a fuse box.
Furthermore, the fuse linked relay 30 of the present invention, although being described with an electromagnetic coil 34, can utilize, for example, a pneumatic or hydraulic system in order to move the movable element 50 towards the contact terminal 54.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.
