JPH02216724A - Overload protection device of motor - Google Patents

Abstract

PURPOSE:To improve attachment operability and follow-up of temperature to a current by providing a heater insertion space between a partition wall between a starter device and an overload protection device and a thermostat element and arranging a heater close to and facing the thermostat element at its high expansion side. CONSTITUTION:A heater insertion space is provided between a partition wall 5 between a starter device 4 and an overload protection device 3 of a motor and a thermostat element 33. Thus, the starter and overload protection devices 4 and 3 of the motor are installed in an unified case 1. Operability of attachment to the motor is improved. A heater 29 is provided in the heater insertion space arranged close to and facing the thermostat element at its high expansion side 33b. Heat produced by the heater 29 due to abnormality of short time trip or last trip of the motor is thus susceptively sensed by the thermostat element. Accordingly, follow up of temperature to a current is improved.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a motor overload protection device.

BACKGROUND OF THE INVENTION Various overload protection devices for motors have been proposed in the past. In recent years, in particular, overload protection devices used in compressors used in refrigerators have been required to reduce costs and improve reliability. For this reason, attempts have been made to miniaturize overload protection devices to meet the above requirements (for example, Japanese Patent Laid-Open No. 61-22
Publication No. 7631). This heel overload protection device disconnects the thermostat element from the electrical circuit, snaps the thermostat element using the heat from the heater and the compressor body, and uses the snap action to push down the leaf spring with the movable contact to open the area between the contacts. The structure is designed to be separated from each other in order to achieve compactness, low cost, and improved reliability.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, the heater is disposed on the lower expansion metal side of the two or three layers of metals having different thermal expansion coefficients forming the thermostat element. As a result, the temperature tracking of the thermostat element due to the heat generated by the heater is poor, and in terms of structure, the heater also slows down the time it takes for the thermostat element in the recess of the outer shell to reverse itself due to a snap action and return to its original state again. Since the shape of the heater is placed along the outer circumferential groove of the protrusion provided for the purpose of The problem was that it had the potential to be damaged. The present invention solves the above-mentioned conventional problems, and provides an integrated starting/overload protection device for a compressor that is easy to install, and in particular improves the ability of the overload protection device to follow current and temperature. It is about providing.

Means for Solving the Problems To achieve this objective, the overload protection device of the present invention comprises:
It consists of a starter unit and an overload protector unit that are integrated into the compressor outer shell, and a partition is provided between the starter unit and the overload protector unit, and a thermostat element that senses the temperature of the motor's outer shell. A heater insertion space is provided between the partition wall and the partition wall.

Note that the heater may be provided in the heater insertion space by being disposed close to and opposite to the high expansion side of the thermostat element.

Function: With this configuration, the heater insertion space is provided between the partition wall between the starter section and the overload protection device section and the thermostat element, so that the heater can be protected from obstacles such as protrusions within the heater insertion space. Since there are no objects, it is possible to have any shape such as a winding shape or a plate shape, and since there is little possibility that the heater will come into contact with the inside of the outer case, the current will not be lost to the case etc. It is possible to sensitively sense the temperature and improve the temperature followability of the current.

In addition, by locating the heater close to and facing the high expansion side of the thermostat element, in the event of a short trip or final trip failure condition of the motor, the heat generated by high current flowing through the heater can be transferred to the thermostat. Since it is directly received from the high expansion side of the element, it can be sensitively sensed.

Example An embodiment of the present invention will be described using FIGS. 1 to 4.

1 is a case, 2 is a cover, 3 is an overload protection device section, 4 is a starting device section, and 5 is a partition wall, which divides the overload protection device section 3 and the starting device section 4 within the case 1. The case 1 is formed by molding an insulating thermosetting resin into a substantially rectangular shape, and has two circular holes 6a near the partition wall 6 and two circular holes 6a in the starting device section 4.

eb, ea, and ad are open respectively, and cover 2 is opened.
The protrusions 7a, 7b, ya, and 7d are fitted respectively.

The cover 2 is made of insulating thermoplastic resin and is molded into a substantially square shape, and has a protrusion 9 on the back surface that comes into contact with the compressor main body 8.
Terminals 10 and 11 are electrically connected to the compressor main body 8.

Circular holes 13a, 13b, and 13c through which 12 is passed are open.

In the starting device section 4, 14 is a ceramic having PTC characteristics (hereinafter referred to as ceramic), 15 and 16 are terminals with an electrode plate, and 17 is a terminal with a bottle. The terminal with electrode plate 15 is an external terminal 1 having one end formed in a generally widely known shape of type 187 or type 250.
8 and a leg portion 19a of an electrode plate 19 formed of a material without spring properties. Another terminal with an electrode plate 16 connects the external terminal 2) with the leg portion 21a of the electrode plate 21 formed of a material having spring properties, and also connects with the main winding 22 of the compressor main body 8. It is connected to a pin terminal 23 formed so as to be press-fitted into the connected terminal 10. 17 is a terminal with a pin, and an external terminal 24 (for this Hafian motor 26) which is a series of two external terminals 18;
If the 1-in motor 26 is not provided, it becomes the external terminal 18. ), and a pin terminal 27 formed so as to be press fit into the terminal 11 connected to the auxiliary winding 26 of the compressor main body 8.
is connected to. The ceramic 14 is formed into a disk shape, is held by the contact portion 19b of the electrode plate 19, and the contact portion 21b of the other electrode plate 21, and is housed in the case 1.

In the overload protection device section 3, 28 is a pin terminal, ?
9 is a heater, 30 is a fixed plate, 31 is a leaf spring with contacts, 3
2 is a terminal with a contact, and 33 is a thermostat element.

The pin terminal 28 is provided with a fitting part 34 formed to be press-fitted into the common terminal 12 of the compressor main body 8, and has a protruding piece 28a on the other end, which is connected to one end 29a of the heater 29. . The other end 29b of the heater 29 is attached to the fixed plate 3o.
The heater insertion space 35 is connected to the protrusion 30a of the heater insertion space 35 in the case 1. used here. Although a spiral shape is used for the side plate 29 for convenience, since there are no protrusions or obstacles that restrict the shape of the heater 29 in the heater insertion space 36, it can have any shape such as a winding shape or a plate shape. It is obvious that it can be done. A contact-equipped plate spring 31 having a movable contact 37 provided at one end of the plate spring 36 is connected to the other protrusion 3ob of the fixed plate 3o, and the protrusion 30c at the other end of the fixed plate 3o is connected to the case. It comes out of the case 1 from the square hole 38 of 1 and is fixed to the υ case 1 by force 7. In the terminal with contacts 32, a fixed contact 40 is provided on the external terminal 39, and the fixed contact 4o is arranged at a position opposite to the movable contact 37 in the X direction. The external terminal 39 has two terminal portions of the 187th type or the 250th type at the negative end, one for the fan motor 25, and one if the fan motor 26 is not provided. ), and a protrusion 39a on the other end.
It comes out of the case 1 through the square hole 41 of the case 1 and is fixed to the case by caulking. Thermostat element 33
is formed from bimetal or trimetal, and includes the head 42a of the beak-shaped projection 42 of the case 1 and the protrusion 3 of the fixing plate 3°.
It has a mechanism that performs a snap operation at a set temperature using ob as a fulcrum. 43 is a support member, and the leaf spring 36
hole 36a near the center of the thermostat element 33
The thermostat element 3 is inserted through the hole SSa in the center of the washer 44 and the hole 4411 of the washer 44, and
3 are caulked and supported in opposing positions.

The operation will now be explained.

Since the ceramic 14 is cold when the compressor main body 8 is started, the resistance is low and current flows through the main winding 22 and the auxiliary winding 26 in the compressor main body 8, providing sufficient starting torque. When the compressor main body 8 starts, the resistance of the ceramic 14 suddenly increases due to self-heating, and the current flowing to the auxiliary winding 26 becomes sufficiently small. Here, in the overload protection device section 3, the movable contact 3a and the fixed contact 4o are normally in a closed state.
When the motor is locked or overloaded, the overload protection device section 3
The heat generated from the heater 29 is directly sensed, and at the same time, the heat from the compressor body 8 is transferred from the protrusion 9 of the cover 2 that is in contact with the compressor body 8 to the temperature of the outer shell of the compressor. The thermostat element 33
When heated to a set temperature, the head 42a of the beak-like protrusion 42 of the case 1 and the protrusion 3ob of the fixing plate 30 are used as fulcrums, and the support member 43 and washer 44 are crimped and supported by a snap action. The leaf spring 36 is the thermostat element 3
At the same time, the movable contact 37 connected to the leaf spring 36 is pulled up to open the closed circuit with the fixed contact 4o.

As described above, by incorporating the overload protection device section 3 and the starting device section 4 into the integrated case 1, it is possible to provide a motor starting/overload protection device with good installation workability.
Furthermore, the effect of the present invention is that by providing the heater insertion space 35 between the partition wall 5 between the starter section 4 and the overload protection device section 3 and the thermostat element 33, the shape of the heater 29 can be freely selected. It can be processed and the workability of installation can be improved.

A case will be described with reference to FIG. 6 in which the heater 29 is provided in the heater insertion space 36 which is disposed in close proximity to the high expansion side of the thermostat element 33. FIG. 5 is a trip characteristic diagram in this embodiment. The characteristics shown by the solid line are those when the heater 29 is placed close to the high expansion side of the thermostat element 33, and compared to the characteristics shown by the broken line when the heater 29 is placed close to the low expansion side of the thermostat element 33. For the same trip current X (ampere), the trip time will be shorter if the heater 29 is placed closer to the high expansion side than Y or Z. Therefore, thermostat element 3
3 can more sensitively sense the heat from the heater 29 and improve the temperature followability of the trip current.

In addition, the startup method of this embodiment is 1/(
C3CR (capacitor start/capacitor fan)
However, other activation methods have the same effect.

Effects of the Invention As described above, the present invention includes a motor starting device and an overload protection device that are housed in a case, and a heater insertion space between the partition wall between the starting device and the overload protection device and the thermostat element. By providing a separate section, the motor startup/overload protection device is downsized and housed in an integrated case, which improves the workability of attaching it to the motor.
Since there are no protrusions or obstacles that restrict the shape of the heater in the heater insertion space, the heater can be machined into any shape.

Furthermore, by providing the heater in the heater insertion space disposed close to and opposite to the high expansion side of the thermostat element, the thermostat element can absorb the heat generated from the heater due to an abnormality in the short-time trip or final trip of the motor. It is possible to realize an excellent motor overload protection device that can sense sensitively, improve temperature followability with respect to current, and prevent motor burnout.

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view of a motor overload protection device according to an embodiment of the present invention, FIG. 1(Φ) is an exploded perspective view of FIG. 1(a), and FIG. ) with the cover removed, FIG. 3 is a central sectional view of one embodiment of the present invention in a state of connection with a compressor, FIG. 4 is an electric circuit diagram of the C3CR method showing connection with a compressor, and FIG. FIG. 5 is a trip characteristic diagram of the thermostat element. 1...Case, 2...Cover, 3...
...Overload protection device section, 4...Start device section, 6...Bulkhead, 28...Pin terminal, 2
9...Heater, 30...Fixing plate, 33
...Thermostat element, 33b...
Thermostat element high expansion side, 36...plate spring, 37...movable contact, 40...fixed contact, 43...support material, 44... ...Washer. Name of agent: Patent attorney Shigetaka Awano and 1 other person3-
m@Mzawa n'f' 1711 parts, i-・4-B support part 33b-・- 5-11 interval Perfect fumostat element Ware star throat element 1 & expansion so-called wing-princess spring 4- Support material Figure Figure ↑ → Trip electric group (Anhe I)

Claims (2)

[Claims] (1) A starting device part and an overload protection device part made of PTC ceramic are provided in the same case, and a partition wall separating the starting device part and the overload protection device part, and a fixed contact in the overload protection device part. and a plate spring having a movable contact, the fixed contact and the movable contact being arranged to face each other, and a fixed plate fixed to the plate spring with electrical connection, and fitted with the fixed plate. An electric path is formed by a pin terminal having a portion and a heater that is conductively fixed, and a thermostat element is disposed near the center of the leaf spring and supported by caulking through a support material, and the thermostat element is heated at a set temperature. Overloading of a motor having a configuration that snaps and biases a leaf spring in a direction to separate a movable contact from a fixed contact, and includes a heater insertion space provided between the thermostat element and the partition wall. Protective device. (2) Overload of the motor as set forth in claim 1, characterized in that a heater is disposed in close proximity to the high expansion side of the thermostat element and is provided in the heater insertion space. Protective device.