WO2007033537A1

WO2007033537A1 - An overload protector for single ac motor

Info

Publication number: WO2007033537A1
Application number: PCT/CN2005/002314
Authority: WO
Inventors: Yunwen Zhao
Original assignee: Changshu Tianyin Electromechanical Co., Ltd.
Priority date: 2005-09-26
Filing date: 2005-12-26
Publication date: 2007-03-29
Also published as: CN1767297A; CN100356652C

Abstract

An overload protector for single-phase AC motor, which, belongs to a motor protector for refrigeration compressor, comprises a housing, a cover, an electrothermal filament secured in a filament chamber by the first pin and the second pin, a disc bimetal provided on a bimetal seat over the filament , the first terminal, the second terminal connected to the second pin, a moving contact, a static contact attached to the first terminal, a securing seat, and a driving mechanism. The driving mechanism includes a driving pin moveable provided in a driving pin hole on the securing seat, and a reed comprising a free end and a fixed end. The ends of the driving pin are corresponding to the bimetal and the reed. The fixed end of the reed is attached to the lower portion of the securing seat. The tree end of the reed extends into the contact chamber on the lower portion of the securing seat. The movable contact is fixed on the free end and is corresponding to the static contact.

Description

Single-phase AC motor overload protector

Technical field

The invention belongs to a motor protector for a refrigeration compressor, and more particularly to an overload protector capable of providing effective protection against temperature over-temperature overload of a single-phase AC motor. Background technique

As an overload protector for a single-phase AC motor, the more common structure is as shown in FIG. 4, and includes a casing 1, a cover for covering the casing 1, and a pair of shells extending to the casing 1 at one end. The first and second pins 5, 6, the heating wire 3, the bimetal 4, and the movable and static contacts a, b, and the static contact b are disposed in the cavity and the other end is located outside the housing of the housing 1. One of the stationary contacts b is electrically connected to one end of the heating wire 3, the other end of the heating wire 3 is connected to the second pin 6, the other stationary contact b is in contact with the first pin 5, and the movable contact a has a pair. It is disposed at both ends of the bimetal 4 and corresponds to a pair of static contacts b, respectively, and the middle portion of the bimetal 4 is fixed on a fixing post extending in the center of the casing of the casing 1. The entire overload protector is connected in series through the first and second pins 5, 6. When the temperature of the single-phase AC motor is over temperature, the bimetal 4 senses the heat of the heating wire 3 and deforms. _a pair of separate movable contact with the pair of stationary contacts B, a first, a second pin 5, circuit 6, but controlled by the bimetal 4 reset its ends a pair of movable contact and A pair of stationary contacts b are closed to electrically turn on the circuits of the first and second pins 5, 6. Although the above structure can exhibit the overload protection effect, the phenomenon of failure due to the defect of the structure of the protector itself often occurs. These defects are manifested as follows: First, since the middle portion of the bimetal 4 is fixed on the fixing post extending in the center of the casing of the casing 1, the two ends respectively protrude the movable contact a, and the structural expression of the entire bimetal 4 For the butterfly shape, because it is a butterfly shape or a horizontal shape, it is obvious that the strength of the middle portion is very fragile. After the repeated deformation action, the middle portion of the bimetal 4 will be cracked soon, and The two ends of the metal piece 4 are riveted/twisted with a pair of silver contacts, that is, the movable contact a, so that the joint portion of the bimetal 4 and the movable contact a is also easily opened, and the presence of cracking causes the temperature to drift, and even makes The bimetal 4 loses its deformation ability; the second is that when the loop is conducting (closed), the bimetal 4 is always in a charged state, that is, the bimetal 4 has a current passing through, that is, the entire loop in the conduction. In the middle, the bimetal 4 itself acts as a resistive element and participates in conduction, thereby adversely affecting the electrical conductivity of the entire circuit; third, there are four contacts, that is, a pair of movable contacts a and a pair of static contacts b, Since the material of the contacts is expensive silver, it is extremely cost-effective to save materials. unfavorable.

The applicant also searched the literature and retrieved the butterfly disclosed in Chinese Patent Publication No. CN2093438U. Shaped bimetal temperature protection relay, bulletin number CN2152301Y gives the thermal compensation type refrigerator over current over temperature rise double protector, bulletin number CN2218263Y disclosed self-protection refrigeration compressor thermal protector, announcement number CN2287339Y introduced refrigeration compression The motor protector, the thermal protector recommended by the authorization bulletin number CN1207743C, and the current-temperature composite motor protector taught by the bulletin number CN2341305Y.

In the above six patent documents, CN2093438Y is a buried type, which is placed in the motor coil and cannot be repaired. Once the protection relay is damaged, it is often replaced together with the motor. Although there are only two contacts, the bimetal The cracking defect of the sheet and the defect that the bimetal acts as a resistive element to participate in the conduction in the state of the circuit conduction; CN 2152301Y and CN2218263Y are all the defects of the structure described by the applicant in the foregoing FIG. 4; CN2287339Y It is the technical proposal proposed by the applicant himself on October 23, 1996. First, because the spring piece (patent called the spring arm) is in contact with the bimetal, under normal working conditions, although the bimetal does not act as The form of the resistive element participates in conduction, but it is charged. Secondly, the bimetal is inferior in temperature or heat radiation, because the structure of the protector and the motor is such that the bimetal cannot be in close contact with the surface of the motor casing, but is in contact with the motor casing. Vertical, so the bimetal is very weak in accepting the heat radiation capability of the motor. There are also spring pieces and electric heating wires (patent called heaters) which are prone to electrical short circuit, because the space between the heating wire and the bimetal is extremely small, and the resistance to mechanical shock is extremely fragile in the production assembly, transportation and other links, which makes it easy to make The electrical clearance between the two becomes smaller. In the process of use, when the circuit is in the conduction state, the arc is often generated, causing a short circuit. These defects are caused by the unreasonable distribution of the electrical structure; CN1207743C is not a category of application field of the refrigeration compressor motor protector. And only the overheat protection, especially the two defects mentioned above, the bimetal is easy to crack and participates in conduction as a resistive element; the lack of CN2341305Y is as explained by the applicant for CN2093438U. Summary of the invention

The object of the present invention is to provide a single electric metal structure with a reasonable distribution, convenient installation, effective prevention of splitting of the bimetal, and no electrical short circuit, and the bimetal is not charged when the circuit is in the conducting state. The overload protector of the phase flow motor. .

The task of the present invention is accomplished by an overload protector for a single-phase AC motor, including a housing, a cover, a heating wire, a bimetal, first and second pins, and dynamic and static contacts. The utility model also comprises a fixing seat accommodated in the casing cavity of the casing and an actuating mechanism for opening/closing the moving and static contacts to each other, the lower part of the fixing seat has a pin cavity, and the upper part The electric wire cavity and the bimetal seat, the first and second bases of the first and second pins are respectively fixed on corresponding sides of the pin cavity, and the first and second pins are first, The second end passes through the first and second pin holes on the housing, the static contact is fixed on the first base, and the heating wire is fixed by a pair The first and second posts in the cavity of the heating wire cavity are fixed in the heating wire cavity, and the second post is connected to the second base, the bimetal is disc-shaped, and is placed on the shelf On the bimetal holder, and corresponding to the upper part of the heating wire; the triggering mechanism comprises a ejector rod and a spring piece, and the ejector rod can be movably placed up and down in the ejector hole formed in the center of the fixing seat, The upper and lower ends respectively correspond to the bimetal and the spring piece, and the fixed end of the spring piece is fixed on the spring piece fixing seat at the lower part of the fixing seat, and the free end of the spring piece extends to the preset contact limit of the lower part of the fixing seat In the cavity, the movable contact is fixed on the free end, corresponding to the static contact fixed on the first base of the first pin.

The first pin of the present invention is inserted into the pin cavity in a plug-in manner.

The second pin of the present invention is inserted into the pin cavity by inserting and inserting. .

The fixing of the second base of the second pin and the second post of the present invention is fixed by any one of welding or riveting.

The fixing between the first post and the fixed end of the spring piece according to the present invention is any one of welding or riveting.

The movable and static contacts of the present invention are respectively fixed to the free end of the spring piece and the first base of the first pin by any one of welding or riveting, and the two face face to face.

The moving and static contacts of the present invention are respectively silver contacts.

The material of the housing of the present invention is plastic.

The material of the fixing seat of the utility model is any one of ceramics or plastics.

The touch mechanism of the present invention further includes a connector for carrying the spring piece to the lower portion of the holder.

One of the advantages of the present invention is that the electrical structure is distributed reasonably and the installation is convenient; and the second is that the design idea of supporting the middle portion of the bimetal in the prior art is eliminated, so that the bimetal is changed from butterfly to butterfly. The formation of the disc is a reality, which can completely eliminate the cracking of the bimetal and the temperature drift of the bimetal 4, thereby ensuring that the overload protector can play the protection function of the overheat and overload for a long time; Third, the prior art is changed. The moving contact is arranged on the bimetal, so as to avoid the condition that the bimetal is always charged when the loop is in the on state; fourth, there is a distance between the spring and the heating wire, and there is no cause. Pulling the arc causes an electrical short circuit; Fifth, in the state of use after installation, the bimetal can be ensured to face the surface of the motor casing through the aluminum cover, and the bimetal receives the heat radiation capability of the motor. . . BRIEF DESCRIPTION OF THE DRAWINGS These and/or other aspects and advantages of the present invention will be more clearly understood and appreciated from the description of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an assembled structural view of an embodiment of the present invention.

Fig. 2 is a view showing another embodiment of the present invention.

Figure 3 is a schematic view of the lower structure of the fixing base.

Fig. 4 is a structural view showing an overload protector of a single-phase AC motor in the prior art according to the present invention. detailed description

Specific embodiments of the present invention will be described in detail with reference to the embodiments illustrated in the accompanying drawings.

In FIGS. 1 and 3, a housing 1 made of plastic has a housing cavity, and a pair of first and second ends for the first and second pins 5, 6 are opened at the bottom of the housing cavity. 52, 62 the first and second pin holes 11, 12, the first and second pin holes 11, 12 are shaped and sized to be compatible with the first and second end portions 52, 62. A step 13 is formed on the outer wall of the upper portion of the casing 1, and the cover 2 is disposed on the step 13, and the cover 2 is preferably made of an aluminum material, and a slightly raised cavity is formed in the center of the cover 2. The fixing member 7 which is made of ceramic or plastic can be integrally accommodated in the casing of the casing 1, and the pin cavity 75 is formed on the lower end surface of the fixing base 7. Specifically, as shown in FIG. 3, the first and second ends 52, 62 of the first and second pins 5, 6 are inserted into the first and second slots 751, 752 of the cavity wall of the pin cavity 75. Above, the first and second bases 51, 61 of the first and second pins 5, 6 are seated on the bottom wall of the cavity of the pin cavity 75, and the front end of the first base 51 of the first pin 5 Extending into the contact stop cavity 74, a static contact b of silver material is fixed to the front end of the first base 51 by soldering or riveting or in other similar manner. The heating wire cavity 72 and the bimetal seat 71 are formed on the upper end surface of the fixing base 7, and the pair of first and second connecting posts 31, 32 for fixing the two ends of the heating wire 3 are firmly fixed to the fixing base 7, that is, Firmly fixed to the end point of the cavity of the heating wire cavity 72, the second post 32 should be reliably electrically connected to the first base 61 of the second pin 6. The bimetal 4, which is also known as a bimetal element, has a disk shape as a whole and rests on the bimetal holder 71. The side facing the heating wire 3 is in contact with the heating wire 3, and when the heating wire 3 is heated, The bimetal 4 can be deformed, and the deformation is expressed as a four-sided upward flip and a central downward recess.

The jack 8 as the actuating mechanism can be vertically (movably) accommodated in the jack hole 73 preset in the center of the fixing base 7, and the upper end surface of the jack 8 corresponds to the center of the bimetal 4, The lower end face corresponds exactly to the free end 91 of the leaf spring 9. As can be seen in particular in connection with Figure 3, the position of the movable contact & silver material on the free end 91 is at the contact stop cavity 74, thereby ensuring that it can correspond to and interact with the stationary contact b. Combined with the map 3. The fixed end 92 of the spring piece 9 is fixed to the lower part of the fixing base 7 through a pair of spring piece fixing seats 76 protruding from the lower end surface of the fixing base 7. The preferred fixing manner is riveting, but it is not excluded. The screws are fixed, and the fixed end 92 of the spring piece 9 is reliably connected to the first post 31, for example, by rivets, the fixed end 92 and the first post 31 are riveted together.

After the installation of all the components mentioned above is completed on the fixing base 7, the fixing base 7 is accommodated in the housing of the housing 1, and is sealed by the cover 2, the first and second pins 5, 6 The first and second end portions 52, 62 extend from the first and second pin holes 11, 12, respectively, for the present invention to be serially connected in the circuit in use.

In Fig. 2, the difference between the embodiment diagram and the previously described Figs. 1 and 3 is only that the form of the pin cavity 75 at the lower portion of the fixing base 7 is slightly changed, and the change is to accommodate the placement of the actuator mechanism. Increased connector 10. That is to say, as the driving mechanism provided by the present invention, in addition to the form shown in FIG. 1, the structural form shown in FIG. 2 can be used, that is, a connecting member 10 is added as a carrier of the spring piece 9, and the connection is made. The piece 10 is placed into the pin cavity 75 with the spring piece 9. Specifically, the fixed end 92 of the spring piece 9 and the connecting member 10 are riveted by rivets, and the free end 91 of the spring piece 9 rests on the connecting member 10. Further, the shapes of the first and second pins 5, 6 are also slightly changed, but the entire assembly process and the connection relationship of the components and even the principle of action are not fundamentally different from the previous embodiments. Therefore, it can be seen that the specific shape of the pin cavity 75, the spring piece 9, the first and second pins 5, 6 on the fixing base 7 can be changed, but it cannot be considered that the change has the technical solution of the invention. As long as the shape of the butterfly-shaped bimetal 4 is disc-shaped, and the movable contact a as an on/off loop is free from the bimetal 4, that is, the long-term charging of the bimetal 4 is avoided. The concept should be considered to be within the scope of the inventive concept.

The definitions of the first and second pins 5, 6 above are also relative, and are only defined according to the positions shown in FIG. 1 and FIG. 3. Therefore, if the first and second pins 5 are The position of 6 is reversed, of course, the corresponding other components are also equivalent, so it should be considered equivalent, for example, the situation shown in Figure 2 belongs to this.

In use, as long as the first and second pins 5, 6 of the present invention are connected in series in an electric circuit, when the bimetal 4 senses the radiant heat of the heating wire 3 or the aluminum cover 2 or the external environment, the bimetal The sheet 4 is deformed, and the deformation is such that the periphery is turned upside down, and the center is recessed downward, thereby pushing the ram 8 to be displaced downward, since the lower end surface of the ram 8 corresponds to the free end 91 of the spring piece 9, Also, since under normal circumstances, the movable contact a on the free end 91 of the spring piece 9 is closed with the stationary contact b on the first base 51 of the first pin 5, when the jack 8 is lowered When displaced, the lower end surface of the ram 8 is pushed toward the free end 91, forcing the position of the movable contact a on the free end 91 to be displaced away from the stationary contact b on the first base 51, thereby making the previous closure The dynamic and static contacts a and b are separated in the state, so that the circuits of the first and second pins 5 and 6 are disconnected, thereby protecting the compressor motor, that is, protecting The function of the single-phase AC motor; when the radiant heat of the heating wire 3 or the aluminum cover 2 or the external environment is lower than the induction temperature of the bimetal 4, the bimetal 4 is reset, and its force on the ram 8 disappears. The free end 91 of the spring leaf 9 is reset, the movable contact a on the free end 91 is closed with the stationary contact b on the first base 51, and the motor circuit is turned back on. In the above process, since the bimetal 4 is not fixed by any fixing member, but is merely placed on the bimetal holder 71, and is disc-shaped, no matter whether the deformation action is repeated any number of times, It will cause cracking; when the circuit is in the closed state, the bimetal 4 is uncharged, that is, no current flows, and the bimetal 4 does not participate in conduction, so it does not affect its performance. Therefore, the advantages of the technical solution proposed by the present invention are very obvious.

While the preferred embodiment of the present invention has been shown and described, it is understood that the scope of the invention and the scope of the invention Equivalent replacements may also be made to these embodiments.

Claims

Rights request

1. An overload protector for a single-phase AC motor, comprising a housing (1), a cover (2), a heating wire (3), a bimetal (4), a first and a second pin (5), ( 6), moving and static contacts (a), (b), characterized in that it further comprises a fixing seat (7) accommodated in the housing cavity of the housing (1) and a movement for the movement The static contact (a), (b) realizes the opening/closing actuation mechanism, the lower part of the fixing seat (7) has a pin cavity (75), and the upper part has a heating wire cavity (72) and a bimetal seat ( 71) The first and second bases (51) and (61) of the first and second pins (5) and (6) are respectively fixed on corresponding sides of the pin cavity (75), and 1. The first and second ends (52) and (62) of the second pins (5) and (6) pass through the first and second pin holes (11) on the housing (1), ( 12), the static contact (b) is fixed on the first base (51), and the heating wire ( ³ ) is first and secondly fixed in a cavity fixed to the heating wire cavity (72) The second post (31), (32) is fixed in the heating wire cavity (72), and the second post (32) is connected to the second base (61), the bimetal (4) ) is a disc shape, Placed on the bimetal holder (71) and corresponding to the upper part of the heating wire (3); the trigger mechanism includes a top rod (8) and a spring piece (9), and the top rod (8) can be moved up and down The ground cover is arranged in a jack hole (73) opened in the center of the fixing seat (7), and the upper and lower ends respectively correspond to the bimetal (4) and the spring piece (9), and the fixed end of the spring piece (9) ( 92) fixed on the spring piece fixing seat (76) at the lower part of the fixing seat (7), the free end (91) of the spring piece (9) is extended to the contact limiting cavity preset by the lower part of the fixing seat (7) (74), the movable contact (a) is fixed to the free end (91), and the static contact (b) fixed to the first base (51) of the first pin (5) )Corresponding.

The overload protector for a single-phase AC motor according to claim 1, characterized in that said first pin (5) is inserted into said pin cavity (75) in a plug-in manner.

The overload protector for a single-phase AC motor according to claim 1, characterized in that said second pin (6) is inserted into said pin cavity (75) in a plug-in manner.

The overload protector for a single-phase AC motor according to claim 1 or 3, characterized in that the second base (61) of the second pin (6) is fixed to the second post (32) It is fixed for any of welding or riveting.

5. The overload protector for a single-phase AC motor according to claim 1, wherein the fixing between the first post (31) and the fixed end (92) of the spring piece (9) is soldering or Any one of the riveting is fixed.

6. The overload protector for a single-phase AC motor according to claim 1, wherein said movable and static contacts (a) and (b) are respectively fixed to the spring by any one of welding or riveting. The free end (91) of the sheet (9) and the first base (51) of the first pin (5) correspond to each other face to face.

7. The overload protector for a single-phase AC motor according to claim 1 or 6, wherein said The moving and stationary contacts (a) and (b) are respectively silver contacts.

The overload protector for a single-phase AC motor according to claim 1, characterized in that the material of the casing (1) is plastic.

The overload protector for a single-phase AC motor according to claim 1, characterized in that the material of the fixing base (7) is any one of ceramic or plastic.

10. The overload protector for a single-phase AC motor according to claim 1, wherein said actuating mechanism further comprises a spring piece (9) for carrying said spring seat (9) to said fixed seat (7) ) the lower connector (10).