JPH02135640A - Bimetallic temperature switch - Google Patents

Abstract

PURPOSE:To improve the heat responsiveness of a switch by providing a ring- like fin situated just under the seating part of bimetal and extending toward a discharge-chamber side, on a plane opposite a plane which the bimetal is seated on the bottom of a projecting part within a discharge chamber housing. CONSTITUTION:A recessed plane 23d is formed on the upper plane of the bottom 23c of a projecting part 23, whereon bimetal 21 is disposed, and the bimetal 21 is seated on the peripheral seating part 23e of this recessed plane 23d. And a ring-like fin 24 is projected toward a discharge-chamber side from a plane opposite the peripheral seating part 23e of the bottom 23c. The fin 24 has its inner circumferential wall 24a situated almost just under the peripheral seating part 23e. The heat that a refrigerant within a discharge chamber 2 has is absorbed by the bottom 23c of the projecting part 23, the fin 24, etc., for being transmitted from the peripheral seating part 23e to the bimetal 21. When a temperature in a refrigerant within the discharge chamber reaches a given bimetal inversion temperature, the bimetal is accordingly displaced with excellent responsiveness for causing a switch to be quickly turned on and off.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a bimetallic temperature switch.
For example, it is applied to a temperature switch that detects the temperature of refrigerant discharged from a refrigerant compressor and turns on and off an electromagnetic clutch that transmits driving force to the refrigerant compressor based on this detection signal.

(Prior Art) Conventionally, a bimetallic temperature switch for detecting the refrigerant temperature of a refrigerant compressor as shown in FIG. 10 has been known (Japanese Utility Model Publication No. 167347/1983).
.

In this bimetallic temperature switch, a discharge port 1b for discharging refrigerant compressed in a compression chamber of a refrigerant compressor is formed in a housing l, and a discharge chamber housing 3 for forming a discharge chamber 2 is connected to the housing by bolts 4. It is fixed at l. A temperature switch 5 made of bimetal is built into the concave portion of the discharge chamber housing 3.

When the bimetal 6 is reversely displaced from the state shown in FIG. 1O, the shaft 28 in contact with the bimetal 6 lifts upward, causing the movable contact 30 at the tip of the movable contact support plate 31 to separate from the fixed contact 46, resulting in electrical continuity. is blocked. To the movable contact support plate 31 to which the movable contact 3.0 is fixed
is a fixed contact support plate 45 connected to the first terminal 38 via the first rivet 13 and to which the fixed contact 46 is attached.
is connected to the second terminal 40 via the second rivet 14.

The bimetal 6 that detects temperature abnormalities of the refrigerant flowing through the discharge chamber 2 is located on the inner space side of the bottom 23c of the protrusion 23 formed by protruding the discharge chamber housing 3 toward the discharge chamber 2, and is located on the inner space side of the bottom 23c of the protrusion 23, which is formed by projecting the discharge chamber housing 3 toward the discharge chamber 2. It is provided at a position where it is easy to detect the refrigerant temperature in the discharge chamber 2 via the refrigerant temperature.

(Problem to be Solved by the Invention) However, according to the conventional bimetallic temperature switch, the bimetal 6 is housed at the bottom of the protrusion 23 formed by protruding the discharge chamber housing 3 toward the discharge chamber 2. In addition, because the compressed refrigerant is a gas, the heat of the refrigerant flowing through the discharge chamber 2 is not transferred to the bimetal 6. There is a problem in that the temperature rise of No. 6 does not follow the refrigerant temperature, resulting in a delay in the thermal response of the switch.

The present invention has been made to solve these problems, and provides a bimetallic temperature switch that increases the heat receiving area and improves thermal response by providing fins near the bimetal that absorb the heat of the refrigerant. The purpose is to

(Means for Solving the Problems) To achieve this, the bimetallic temperature switch of the present invention includes a discharge chamber housing fixed to a housing of a compressor, and a discharge chamber housing formed inside the discharge chamber housing for discharging fluid discharged from the compressor. a discharge chamber into which the discharge chamber is guided; a protrusion formed by protruding the discharge chamber housing toward the discharge chamber; an internal space formed by the protrusion on a side opposite to the discharge chamber; a bimetal positioned and provided at the bottom of the protrusion, a shaft that is displaced when the bimetal is reversed, a fixed contact fixed to the internal space, and a contact released from the fixed contact upon displacement of the shaft. A movable contact point, and an annular fin located directly below the seating portion of the bimetal and extending toward the discharge chamber side is provided on the bottom surface of the protruding portion opposite to the surface on which the bimetal is seated. do.

(Function) According to the bimetallic temperature switch of the present invention, the fins extending toward the discharge chamber are formed on the surface of the protruding portion opposite to the surface on which the bimetal is seated, so that the heat receiving area of the refrigerant by the fins increases, and Through the bottom wall, the heat from the refrigerant is quickly transferred, and the heat is transferred to the bimetal in a responsive manner.

Therefore, when the temperature of the refrigerant in the discharge chamber reaches a predetermined bimetal reversal temperature, the bimetal is displaced in a responsive manner, and the switch is quickly turned on and off.

(Example) Embodiments of the present invention will be described based on the drawings.

1 to 5 show a first embodiment in which the present invention is applied to a temperature switch that detects the temperature of refrigerant discharged from a refrigerant compressor.

A discharge chamber housing 3 fixed to a housing l of the compressor with bolts 4 has a discharge port 1 formed in the housing l.
It has a discharge chamber 2 communicating with b. In the discharge chamber 2, a discharge valve IO for opening and closing the discharge port 1b is fixed to the housing l by a valve holder 11 and a bolt 12.

The discharge chamber housing 3 is formed with a protrusion 23 that protrudes toward the discharge chamber 2 described above, and the protrusion 23 includes a large diameter part 23a and a small diameter part 23b. This protrusion 2
3, an internal space 41 is formed on the side opposite to the discharge chamber 2, and the bimetal 21 is disposed on the upper surface of the bottom 23c.

This disc-shaped bimetal 21 is in a downwardly convex state as shown in FIG. 1 below a predetermined bimetal inversion temperature, and is reversely displaced to an upwardly convex state in FIG. 1 when the temperature exceeds a predetermined temperature. . As shown in FIG. 4, a concave surface 23d is formed on the upper surface of the bottom portion 23c where the bimetal 21 is disposed, and the bimetal 2
1 is seated.

An annular fin 24 is protruded toward the discharge chamber from a surface of the bottom 23c of the protrusion 23 opposite to the seating portion 23e. In the annular fin 24, the fin inner circumferential wall 24a is located almost directly below the seating portion 23e. The heat of the refrigerant in the discharge chamber 2 is absorbed by the bottom 23c of the protrusion 23, the fins 24, etc., and is transmitted to the bimetal 21 from the seat 23e.

A leaf spring 25 is provided on the top surface of the bimetal 21, and the leaf spring 25 pushes the bimetal 21 into the bottom 23c.
is being pressed. Further above the leaf spring 25, a stepped cylindrical holder 26 is housed and fixed to the inner peripheral wall of each of the large diameter portion 23a and the small diameter portion 23b. This holder 26
The bimetal 21 and the leaf spring 25 are located between the bottom 26b and the concave surface 23d. A cylindrical shaft 28 made of resin is slidably inserted into a cylindrical shaft guide portion 26a formed at the center of the holder 26. One end of the shaft 28 is in contact with the center of the upper surface of the bimetal 2I, and the other end is in contact with a protrusion 31a of a movable contact support plate spring 31, which will be described later.

The connector body 34 provided above the holder 26 via an O-ring 33 is made of, for example, injection molded resin, and has a metal fixing plate 35 integrally molded therein by insert molding. This fixing plate 35 is placed on the upper end surface of the discharge chamber housing 3 and is fixed to the ejection chamber housing 3 with bolts 36. Further, a first terminal 38 and a second terminal 4o, each of which is crimped and fixed by a first rivet 37 and a second terminal 4o which is crimped and fixed by a second rivet 39, are insert-molded in the connector body 34, respectively. One ends of the first rivet 37 and the second rivet 39 protrude toward an internal space 41 formed inside the holder 26.

First and second rivets 37, 39 and connector body 3
The seal between the first and second rivets 37.3
This is ensured by making 9 into a grooved shape. Furthermore, push plates 42 and 43 are fixed to the protruding ends of the first rivet 37 and the second rivet 39 by opening the hollow protruding ends and caulking them.

By opening and caulking one end of the first rivet 37 and the second rivet 39, the movable contact support plate spring 31 is caulked and fixed to the first rivet 37, and at the same time, the fixed contact support plate 45 is caulked and fixed to the second rivet 39. . The movable contact support plate spring 31 and the fixed contact support plate 45 are each made of metal with excellent conductivity, and the movable contact 30 is fixed to the tip of the movable contact support plate spring 31 and fixed to the tip of the fixed contact support plate 45. Contact 46 is fixed. The movable contact 30 is a fixed contact 46
It is located above the bimetal 2 in FIG.
1 is in a downward convex state, it is pressed against the fixed contact 46 by the biasing force of the movable contact support leaf spring 31. A protrusion 31a is formed in the center of the movable contact support plate spring 31, and one end of the shaft 28 is in contact with this protrusion 31a.

FIG. 2 shows the above-mentioned temperature switch section viewed from above in FIG. 1. As is clear from FIG. 2, the fixing plate 35 has a triangular shape.

The first terminal 38 is connected to a positive terminal of a battery 47, and the second terminal 40 is connected to an electromagnetic clutch 48 and then grounded.

When current is supplied to the bimetallic temperature switch in the state shown in FIG. 1, the electromagnetic clutch 48 is turned on, and the refrigerant compressor is rotated by the driving force of the engine. That is, the current supplied from the battery 47 to the first terminal 38 is
It flows through the first rivet 37 and the movable contact support plate spring 31 to the movable contact 3o, and further flows through the circuit connecting the fixed contact 46, the fixed contact support plate 45, the second rivet 39 to the second terminal 40, and the electromagnetic clutch 48 is turned on. The refrigerant compressor will rotate normally.

When the temperature of the refrigerant flowing through the refrigeration cycle rises above a predetermined value, the bimetallic temperature switch turns off, i.e.
For example, when the amount of refrigerant decreases due to refrigerant leaking from a pipe connection, the temperature of the refrigerant in the discharge chamber 2 becomes abnormally high, and the heat of this refrigerant is transferred to the fins 24, the bottom 23c of the protrusion 23, etc. The information is immediately transmitted to Bimetal 21. When the bimetal 21 rises to the inversion temperature, the bimetal 21 jumps from the state shown in FIG. 1 or FIG. 4 to an upwardly convex state. Then, the shaft 28 is pushed upward in FIG.
8 pushes up the movable contact 30,
The movable contact 30 and the fixed contact 46 are separated, and the current flowing from the first terminal 38 to the second terminal 40 is interrupted. Then, the electromagnetic clutch 48 is turned off, and the rotation of the refrigerant compressor is stopped. This stops the temperature rise of the refrigerant and prevents overheating and damage to the refrigerant compressor.

After that, the refrigerant temperature in the discharge chamber 2 decreases, and the bimetal 2I
When the shaft 28 is again displaced downwardly into a convex state as shown in FIG. 1, the shaft 28 is lowered by the spring load of the movable contact support plate spring 31, and the movable contact 30 and the fixed contact 46 are pressed into contact with each other. This causes the current in the circuit described above to flow,
The electromagnetic clutch 48 is turned on and the refrigerant compressor resumes rotation.

In this way, the heat of the refrigerant in the discharge chamber 2 is quickly transferred to the fins 24 having a large heat receiving area, and the heat is transferred to the bottom part 23c.
, the temperature of the refrigerant is quickly transmitted to the bimetal 21 via the seating portion 23e, etc., so the bimetal 21 responds accurately in accordance with the temperature of the refrigerant, and when the predetermined reversal temperature is reached, the bimetal 21 performs a jumping operation, causing the movable contact to 30 and fixed contact 46 are properly released from contact. therefore,
The electromagnetic clutch can be turned on and off according to the refrigerant temperature, preventing overheating of the refrigerant compressor, etc., and reliably preventing damage.

FIG. 6 shows the relationship between the length of the fin 24 and the thermal response of the bimetal 21 in the first embodiment described above. According to the graph shown in Figure 6, the longer the fin length is, the better the thermal response becomes.
It can be seen that the thermal response is almost at its best in the range of 3 to 5 mm.

If the length β of the fin becomes longer than this range, workability during fin production will deteriorate.

7 to 9 show a second embodiment of the invention. In the second embodiment, two slits 24b and 24c are provided at opposing positions in the diametrical direction of the fin 24. When these slits 24b and 24c are formed in the fins 24, the heat receiving area of the fins 24 is further increased, the heat absorption efficiency of the refrigerant in contact with the fins is improved, and the heat is transferred to the bimetal 21 located on the opposite side of the bottom portion 23c. The conduction efficiency is further improved.

In the second embodiment, the cuts of the slits 24b and 24c are extended to the bottom 23c of the protrusion 23, but in the present invention, the cuts of the slits may be stopped at the middle part of the fin 24.

Furthermore, although the number of slits shown in this second embodiment is two, it goes without saying that the present invention does not need to provide slits, and the number of slits is also limited to the embodiment described above. It's not something.

(Effects of the Invention) As explained above, according to the bimetallic temperature switch of the present invention, the bottom of the protrusion formed by protruding the discharge chamber housing toward the discharge chamber has a surface opposite to the surface on which the bimetal is seated. Since the structure is such that annular fins are provided that are located directly below the seating area and extend toward the discharge chamber, the fins with a large heat-receiving area quickly absorb the heat of the refrigerant, and this heat is quickly transferred to the bimetal. Accurate displacement of the bimetal corresponding to the refrigerant temperature can be obtained, which has the effect of improving the thermal response of the switch.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a first embodiment of the present invention, Fig. 2 is a schematic plan view thereof, Fig. 3 is a partial perspective view showing main parts of the first embodiment, and Fig. 4 is a sectional view showing the present invention. FIG. 5 is a partial cross-sectional view showing the main parts of the first embodiment, and FIG. 5 is a cross-sectional view showing the bimetal.
FIG. 6 is a diagram showing the relationship between the length of the fin and thermal response of the first embodiment of the present invention, and FIG. 7 is a partial perspective view corresponding to FIG. 3 showing the second embodiment of the present invention. FIG. 8 shows the second embodiment of the present invention.
FIG. 9 is a bottom view as seen from the direction of the arrow (■) shown in FIG. 8, and FIG. 10 is a cross-sectional view showing a conventional example. l...2...3...2 l...23...23c...24...25...30...3 l...4 I...46...・Compressor housing, discharge chamber, discharge chamber housing, bimetal. Protrusion, bottom, fin, leaf spring. Movable contact, movable contact support leaf spring, and internal space. Fixed contact.

Claims (1)

[Claims] (1) A discharge chamber housing fixed to the housing of the compressor, a discharge chamber formed inside the discharge chamber housing to which discharge fluid from the compressor is guided, and the discharge chamber housing protruding toward the discharge chamber side. a protrusion formed by the protrusion, an internal space formed by the protrusion on the side opposite to the protrusion chamber, a bimetal located in the internal space and provided at the bottom of the protrusion, and when this bimetal is reversed, A bimetallic temperature switch comprising a displacing shaft, a fixed contact fixed in the internal space, and a movable contact that releases contact with the fixed contact in response to displacement of the shaft, wherein: at the bottom of the protruding part; A bimetallic temperature switch characterized in that an annular fin is provided on a surface opposite to the surface on which the bimetal is seated, located directly below the seating portion of the bimetal and extending toward the discharge chamber side.