JP2522898Y2 - Positive characteristic thermistor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a PTC thermistor device, and more specifically, applies a large starting torque to a capacitor-starting type or a phase-starting type single-phase induction motor. For a positive-characteristic thermistor device incorporating a positive-characteristic thermistor element used in a starting circuit for the same.

[Background Art] In recent years, in a capacitor-start type or phase-start type single-phase induction motor, a PTC thermistor element is frequently used as a means for opening and closing a start circuit.

For example, as shown in FIG. 5, the main winding L ₀ between the terminals 1 and 2, The capacitor activated the auxiliary winding L ₁ was set to be connected between the terminals 1 and 3 of the single-phase induction motor M _1, while connecting the terminal 1 to the AC power source G via a power switch SW, connected to the PTC thermistor 4 and the starting capacitor C in series between the terminals 3 connect the terminal 2 to an AC power source G, the current that flows when turned on the power switch SW by heating the PTC thermistor 4 increases the resistance value, the start of the single-phase induction motor M ₁ when completed, so that to reduce the loss as substantially disconnects the auxiliary winding L ₁ and the capacitor C from the AC power source G.

Further, as shown in FIG. 6, in the case of single-phase induction motor M ₂ of phase separation activated, as in the case of the Figure 5, the PTC thermistor 4 to the energization of the auxiliary winding L ₁ operates as switching means for substantially closing, when the start of the single-phase induction motor M ₂ is complete, with less loss of the single-phase induction motor M ₂ to disconnect the auxiliary winding L ₁ from an AC power source G I have.

FIG. 7 shows a capacitor-start type single-phase induction motor (for example, a hermetic seal type compressor motor) M ₁
In the case of, a specific configuration is shown. According to Figure 7, the PTC thermistor device A and starting capacitor C which dedicated positive thermistor element 4 is disposed on the chassis 5, a glass terminal (terminal) 1 and 2 the single-phase induction motor M _1, 3. The positive characteristic thermistor device A and the starting capacitor C are wired according to FIG.

Further, as a positive temperature coefficient thermistor device used for a starting circuit of such a single-phase induction motor, there has been a structure which is directly attached to a glass terminal of the single-phase induction motor.

[Problems to be Solved by the Invention] Since the positive temperature coefficient thermistor element housed in the outer case of the positive temperature coefficient thermistor device as described above is made of a ceramic thermistor, chlorine and other halogen substances invading from the outside. Of harmful substances may cause performance degradation. When the positive temperature coefficient thermistor element is deteriorated, the element is destroyed. In the worst case, the ceramic is melted and a short circuit occurs between the electrodes of the element. In this state, the temperature of the positive temperature coefficient thermistor element rises to 1000 ° C. or more, and there is a risk that the synthetic resin outer case may ignite.

As a safety measure, for example, as disclosed in Japanese Utility Model Laid-Open No. 59-123301, the connecting portion between the spring contact elastically contacting the positive temperature coefficient thermistor element and the external connection terminal is made narrower, and the temperature fuse is set. Some have the function of. However, in the conventional example, the narrow connection portion is formed of the same material as the spring contact and the external connection terminal, and is merely thinned. Therefore, the function of the thermal fuse could not be sufficiently achieved.

The present invention has been made in view of the above-described drawbacks of the conventional example, and its purpose is to provide a circuit including a positive temperature coefficient thermistor element when the temperature of the internal positive temperature coefficient thermistor element rises abnormally. An object of the present invention is to provide a safe PTC thermistor device that can reliably cut off flowing current.

[Means for Solving the Problems] For this reason, the first positive temperature coefficient thermistor device according to the present invention includes an insulating outer case in which a space for holding the positive temperature coefficient thermistor element is provided, and a fixed outer case. A pair of external connection terminals provided, a pair of holding portions connected to the external connection terminals, a pair of spring contacts held in the outer case by being further connected to the holding portion, In a positive temperature coefficient thermistor device including a positive temperature coefficient thermistor element elastically held between a pair of spring contacts, the external connection terminal includes a fitting portion having a spring property, and the spring contact includes a spring property. A spring piece extending from a base having a, the tip of the spring piece is bent into a hook shape to form a contact with the thermistor element,
The holding unit is made of a non-self-recoverable heat-sensitive deformable element,
By deforming when the temperature rises excessively, at least one of the spring contacts connected to the holding portion is separated from the positive temperature coefficient thermistor element.

[Operation] In the positive temperature coefficient thermistor device according to the present invention, the holding portion holding the spring contact is formed by a heat sensitive deformation element that deforms when the temperature rises and separates the spring contact from the positive temperature coefficient thermistor element. Therefore, for example, when the positive temperature coefficient thermistor element is short-circuited due to performance deterioration and abnormal temperature rises, the heat sensitive deformation element senses the abnormal temperature rise and deforms, and the spring contact is changed from the positive temperature coefficient thermistor element. Separated to interrupt the current between the spring contact and the PTC thermistor element. For this reason, even if the positive temperature coefficient thermistor device fails, there is no possibility that the positive temperature coefficient thermistor element or the outer case emits smoke or fire, and a safe starting circuit can be configured.

In addition, in the present invention, since a non-self-recovering thermosensitive deformation element is used for the holding portion, the holding portion can be irreversibly thermally deformed, and the circuit is once opened when the temperature rises. Then, even if the temperature becomes low, the circuit is not turned on again, the current can be reliably shut off, and the operation reliability of the positive temperature coefficient thermistor device when the temperature rises can be improved. Furthermore, an external connection terminal,
By separately forming the holding portion and the spring contact from the divided members, it becomes possible to select an appropriate material and an appropriate shape according to each function. Further, the external connection terminal is provided with a fitting portion having a spring property, thereby facilitating electrical connection with the outside, and a tip end of a spring piece provided at the spring contact is bent into a hook shape. Because
The contact point with the thermistor element becomes reliable.

[Embodiment] Hereinafter, an embodiment in which the present invention is applied to a phase-separated starting type starting device will be described in detail.

FIG. 2 shows a positive temperature coefficient thermistor device A directly attached to the glass terminals 2 and 3, where 10 is an outer case, 11 is a positive temperature coefficient thermistor element, 12 and 13 are external connection terminals, and 14 and 15 are shown. Is a spring contact.

The outer case 10 is formed, for example, by molding a heat-resistant resin having an insulating property into a rectangular box shape, and has a housing space 16 for the positive temperature coefficient thermistor element 11 therein. The case 10 may be made of ceramic or the like in addition to resin.

On the other hand, the external connection terminal 12 is made of a metal plate having a spring property such as brass or phosphor bronze, and as shown in FIG.
At one end, there is provided a fitting portion 17 formed so as to be press-fitted into the pin-shaped glass terminals 2, 3 (see FIG. 8), and projecting pieces 18a, 18b are protruded from both sides of the other end. Let me.

Further, the spring contact 14 is formed by punching a thin stainless steel plate or the like, and two spring pieces 21 from both sides of the upper end of the coupling plate 20.
a and 21b are respectively protruded, while the two spring pieces 22a and 22b are also protruded from both sides of the lower end, and the spring pieces 21a, 21b and 22a, 22b are pressed against the coupling plate 20 by pressing. , Each base is bent so as to form an angle slightly larger than 90 °, and each tip is bent like a hook.

Further, a plate-like holding portion 19 formed by a heat-sensitive deformable element protrudes from one side of the coupling plate 20. The heat-sensitive deformable element referred to herein is one that deforms when an abnormal temperature is sensed, and a bimetal plate, a shape memory alloy plate, or the like can be used. For example, a holding member 19 having a bimetal structure by joining dissimilar metals to a back surface of a protruding piece integrally provided from the coupling plate 20, or a heat-sensitive deformable element such as a bimetal plate or a shape memory alloy plate may be used. May be fixed by spot welding or the like. Further, the holding portion 19 is connected to the protruding piece 18a of the external connection terminal 12 by spot welding or the like. The holding portion 19 is deformed when the temperature rises, and retreats the spring contact 14 in the α direction in FIG. 1A with respect to the fixed external connection terminal 12. Since the normal temperature of 13 and the spring contacts 14 and 15 rises to 200 to 250 ° C., the deformation temperature (transformation temperature) of the heat-sensitive deformable element constituting the holding section 19 is preferably 300 to 500 ° C.

As shown in FIG. 1 (b), another external connection terminal 13 is a tab-on connection terminal having a lower end formed in a generally well-known shape of a 187 type or a 250 type.
23, the upper end side is a fitting portion 17 that can be pressed into the glass terminals 2 and 3, and the projecting pieces 18a and 18b project from both sides. A spring contact 15 having a shape symmetric to the spring contact 14
A holding portion 19 made of a heat-sensitive deformable element protruding from is connected to one protruding piece 18a.

Of the external connection terminals 12 and 13 integrally assembled with the spring contacts 14 and 15 as described above, the external connection terminal 12 is
As shown in FIG. 2, in a housing space 25 formed by a plate-like housing member 24 provided to protrude from the bottom of the outer case 10 so as to surround a lower right corner of the outer case 10 and the corner, At the same time, the holding portion 19 is inserted into the slit 26 provided between the housing member 24 and the outer case 10 so that each tip of the spring pieces 21a, 21b and 22a, 22b of the spring contact 14 has a positive characteristic. It protrudes into the accommodation space 16 of the thermistor element 11.

On the other hand, the external connection terminal 13 has a slit for inserting the tab-on terminal 23 into the bottom of the accommodation space 28 formed by the same accommodation member 27 and the corner provided above so as to surround the upper right corner of the outer case 10. (Not shown) to insert the tab-on terminal 23 and, similarly to the above, insert the holding portion 19 into the slit 29 provided between the housing member 27 and the outer case 10, and 15 spring pieces 21a, 21b and 22
a, 22b is the accommodation space 1 of the PTC thermistor element 11.
6 to protrude.

In a normal state before the holding portion 19 is deformed, as shown in FIG. 4 (a), the spring pieces 21a, 21b and 2
2a, 22b and the spring piece 21 of the spring contact 15
The positive-characteristic thermistor element 11 is sandwiched between each of the a (21b) and 22a (22b) and the tip (contact point) of 22a (22b) to accommodate the outer case 10
16 and press-contact the respective contact portions of the spring pieces 21a, 21b and 22a, 22b of the spring contact 14 to the electrode 11a of the PTC thermistor element 11, and to the other electrode 11b of the PTC thermistor element 11. The respective contact portions of the spring pieces 21a, 21b and 22a, 22b of the spring contact 15 are pressed against each other.

As described above, in the state where the positive temperature coefficient thermistor element 11, the spring contacts 14, 15 and the external connection terminals 12, 13 are mounted, a part of each of the fitting portions 17, 17 is exposed in the outer case 10. (Not shown) is attached.

If the positive-characteristic thermistor device has the above configuration, the positive-characteristic thermistor device has a circuit configuration as shown in FIG. The positive temperature coefficient thermistor device A is a straight-fitting portions 17 and 17 of the external connection terminals 12 and 13 respectively fitted to the glass terminal 2 and 3 of the single-phase induction motor M _2, the single-phase induction motor M ₂ The tab-on connection terminal 23 serves as a connection terminal to the AC power supply G, and can constitute a single-phase induction motor of a phase-separated start type as shown in FIG.

In the positive temperature coefficient thermistor device A as described above, when the positive temperature coefficient thermistor element 11 is short-circuited due to, for example, performance deterioration or destruction of the positive temperature coefficient thermistor element 11, the abnormal temperature rise is sensed and held. The portion 19 is deformed, and the two spring contacts 14, 15 are retracted as shown in FIG. 4 (b), and the current is cut off between the spring contacts 14, 15 and the positive temperature coefficient thermistor element 11. For this reason, thermal runaway of the PTC thermistor element 11 is prevented, and the risk of smoke or ignition is prevented. The holding portion 19 is made of a special bimetal that does not return to its original shape after being deformed once, a shape memory alloy that recovers a memory shape only when it passes upward through a transformation point, and the like, and is held at the original temperature. Even if lowered, it does not return to its original shape, preventing the spring contact from coming into contact with the positive temperature coefficient thermistor 11 again before the power is turned off.

In the above embodiment, both spring contacts are connected to the external connection terminals via the holding portions, respectively, but only one of the spring contacts is connected via the holding portion, and the other spring contact is directly connected to the external device. It can be connected to the connection terminal.

In the above embodiment, the description has been given of the case of the positive characteristic thermistor device directly attached to the split-phase start type single-phase induction motor. The thermistor device may be a thermistor device or, as shown in FIG. 7, a positive temperature coefficient thermistor device of a type mounted on a chassis.

According to the present invention, when the temperature of the positive temperature coefficient thermistor element rises abnormally, it is sensed by the heat sensitive deformation element, and the spring contact is separated from the positive temperature coefficient thermistor element by the deformed heat sensitive deformation element. The supply of current to the thermistor element can be quickly cut off. Therefore, thermal runaway of the PTC thermistor element can be prevented with a simple structure, and there is no danger of smoking or ignition, and a safe starting circuit can be configured. In addition, in the present invention, since a non-self-recovering thermosensitive deformation element is used for the holding portion, the holding portion can be irreversibly thermally deformed, and the circuit is once opened when the temperature rises. Then, even if the temperature becomes low, the circuit is not turned on again, the current can be reliably shut off, and the operation reliability of the positive temperature coefficient thermistor device when the temperature rises can be improved.

[Brief description of the drawings]

1 (a) and 1 (b) are perspective views showing the structure of a terminal portion in one embodiment of the PTC thermistor device of the present invention, FIG. 2 is a structural explanatory view of the PTC thermistor device, and FIG. 4 (a) and 4 (b) are explanatory diagrams of the operation of the above-described positive-characteristic thermistor device, FIG. 5 is a drive circuit diagram of a capacitor-activated single-phase induction motor, and FIG. FIG. 7 is a drive circuit diagram of the starting type single-phase induction motor, and FIG. 7 is a substantial circuit diagram of FIG. 10,40 ... Outer case 11 ... Positive thermistor element 12,13,42,43 ... External connection terminal 14,15,44,45 ... Spring contact 16,46 ... Storage space 19,49 ... Holding part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masahito Mihara 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Takayoshi Katsuki 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (56) References JP-A-1-235301 (JP, A) JP-A-62-129883 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] An insulating outer case having a space for holding a PTC thermistor element therein, a pair of external connection terminals fixed to the outer case, and an external connection terminal connected to the external connection terminal. A positive electrode comprising: a pair of holding portions; a pair of spring contacts held in the outer case by being further connected to the holding portion; and a positive temperature coefficient thermistor element elastically held between the pair of spring contacts. In the characteristic thermistor device, the external connection terminal includes a fitting portion having a spring property, the spring contact includes a spring piece extending from a base having the spring property, and a tip of the spring piece has a hook. Forming a contact with the thermistor element, and the holding portion is made of a non-self-recovering heat-sensitive deformable element;
A positive temperature coefficient thermistor device characterized in that at least one of said spring contacts connected to said holding portion is separated from a positive temperature coefficient thermistor element by deforming when the temperature rises excessively.