JPH0219571B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermostat that has a wide temperature setting range and operates with high sensitivity. In conventional thermostats, a method of increasing the stroke of the cam or a method of increasing the load scale of the spring is adopted as a means for widening the temperature setting range. By the way, there is a limit to increasing the cam's stroke due to the allowable stress of the spring, so it is inevitable to rely on the method of increasing the load scale by increasing the wire diameter of the spring, etc.
In this case, it is inevitable that the sensitivity (difference between on and off of the switch) increases in direct proportion to the spring load scale, and a wide range and high sensitivity in a thermostat are mutually exclusive. However, it was extremely difficult to achieve both. In contrast, in the present invention, a leaf spring is opposed to a pressure-responsive member such as a bellows with its middle part, and one side of the leaf spring is used as a spring part for the temperature setting range, and the other side is used as a spring part for the temperature setting range. When used as a setting spring part, it was discovered that the temperature setting range spring part and the sensitivity setting spring part function independently of each other, and based on this knowledge, an auxiliary spring was added to the temperature setting range spring part. By polymerizing and using the thermostat, it is possible to widen the temperature setting range of the thermostat without decreasing its sensitivity. An embodiment of the present invention will be described below with reference to the drawings. In the drawing, A is a synthetic resin casing;
It consists of a front casing A ₁ and a rear casing A ₂ , which are connected by means described later to constitute a front wall 1, a rear wall 2, and four peripheral walls 3, 3', 3''. is provided with a bellows 4 as a pressure-responsive body, the fixed surface 4a of which is welded with solder or the like to a bottom plate 6 to which one end of a capillary tube 5 is welded, with the tip of the capillary tube open inside the bellows 4. Although not shown in the drawings, A temperature sensing portion is provided at the other end of the capillary tube. A switch S is provided on the surrounding wall 3' facing the surrounding wall 3. That is, a switch S is provided on the surrounding wall 3'. A contact terminal 8 is fixed, a fixed contact 9 is provided to the fixed contact terminal 7, and a movable contact plate 11 having a movable contact 10 is fixed to the movable contact terminal 8 in an electrically conductive state by caulking or the like.Movable. A snap actuating plate 11a is provided inside the contact plate 11 by a notch as is known in the art, and a quick reversal spring 1 is provided between the movable contact plate 11 and the snap actuating plate 11a.
2 is provided. The peripheral wall 3' is further provided with a differential adjustment screw 13 for adjusting the contact spacing. The movable surface 4b of the bellows 4 and the movable contact plate 11 to the snap operating plate 11a of the switch S are in a state of opposing each other, and there is a gap between them that controls the movement of the bellows 4.
An operating rod 14 is provided for transmitting the signal to the user. That is, the head 14a at one end of the operating rod 14 is connected to the bellows 4.
The locking portion 14b at the other end is coupled to the snap operating plate 11a, and the action of the bellows 4 is controlled by the action of a leaf spring (to be described later).
to open and close it. At this time, the operating rod 14 is supported and guided by the groove 15a of the partition wall 15. A leaf spring 16 is provided between the bellows 4 and the switch S to oppose the operation of the bellows 4 and to set the control temperature of the controlled portion. The leaf spring 16 is a rectangular thin spring plate having a constant width and is bent into an arcuate portion 1.
6a and fold back to form the long side 16b and the short side 1.
6c is integrally formed into a modified U-shape, and an insertion hole 16d is formed in the middle of the long side portion 16b.
In the installed state, the end 16e of the long side 16b comes into contact with a fulcrum 15b protruding from the partition wall 15 in the direction of the peripheral wall 3 that supports the bellows 4, and the insertion hole 16
The operating rod 14 is loosely fitted into the insertion hole 16d.
The peripheral edge of the bellows 4 comes into contact with the head 14a of the actuating rod, thereby opposing the bellows 4 via the actuating rod 14. A sliding adjustment plate 17 is provided on the short side 16c of the leaf spring 16.
The drive piece 17a formed by bending a part of the drive piece 17a comes into contact, and the protrusion 17a ₁ engages in the hole 16c ₁ . The sliding adjusting plate 17 is provided in the recess 1a of the front wall 1 of the upper housing _A1 so as to be movable in the axial direction of the operating rod 14, and has a long hole 1 facing in the moving direction inside.
7b, in which the bearing portion 1b of the camshaft 18 is located. The driving piece 17a passes through a hole provided in the front wall 1 (not shown). As a result of the above, the sliding adjustment plate 17 is located on the side in the direction intersecting the extension direction of the leaf spring 16. An engagement protrusion 17c is erected at one end of the elongated hole 17b of the sliding adjustment plate 17, and is engaged with a cam plate 19 provided on the camshaft 18. In the rear casing A ₂ , a load adjustment screw 20 for a plate spring is screwed into the bellows side peripheral wall 3 so as to be able to move forward and backward, and its inner end abuts against the fulcrum 15 b at the end 16 e of the long side operating portion 16 b of the plate spring 16 . It is coupled further outward than the section. In the long side portion 16b, the contact portion with respect to the fulcrum 15b is configured on the opposite side to the opposite side to the bellows 4. In the leaf spring 16, the part that comes into contact with the head 14a of the operating rod, that is, the insertion hole 1 facing the bellows 4
An arc-shaped bent portion 16 is formed with the peripheral edge portion of 6d as a boundary.
One side including a constitutes a temperature setting range spring part X in which the operating temperature is changed over a wide range by a cam plate 19, and the other side constitutes a spring part X for a temperature setting range in which the operating temperature is changed over a wide range by a cam plate 19, and the other side is used to turn on the switch S, which is finely adjusted by a load adjustment screw 20. The sensitivity setting spring section Y for the off-difference is configured, and a change in the set temperature in the temperature setting range spring section X operates independently with almost no effect on the set value of the sensitivity setting spring section Y. We obtained the following knowledge. Therefore, in the present invention, in the temperature setting range spring section The auxiliary spring 16' is provided in an overlapping manner to enlarge the temperature setting range.
It has an insertion hole 16a' into which it loosely fits. 21 is a metal lid plate that covers the front wall 1, and the bellows 4 is attached to the lid plate 21.
Connecting plates 21a, 21a are provided on opposing peripheral walls 3'', 3'' in a direction intersecting the mounting peripheral walls 3, 3' of the switch S, and the connecting plates 21a, 21a are bent.
At the end of 1a, the peripheral wall 3'' of the rear casing _A2 ,
The caulking connecting pieces 21b, 21b, which position the connecting protrusions 22, 22 formed on the outer surface of the 3'' inside, are successively provided, and the caulking connecting pieces 21 are disposed in succession during assembly.
By caulking the ends of b, 21b to the connecting protrusions 22, 22, the cover plate 21 is attached to the housing A.
At the same time, ensure that the front and rear casings A ₁ and A ₂ are secured together. An insertion hole 21 for the camshaft 18 is provided in the center of the cover plate 21.
c is formed, and outwardly projecting mounting plate portions 21d are continuously provided at both ends thereof. Therefore, the camshaft 18 is connected to the hole 21c of the cover plate 21 and the bearing part 1 of the front wall 1.
It is held in a stable posture by b. In the above configuration, gas pressure corresponding to the temperature of the temperature sensing part is transmitted into the bellows 4 via the capillary tube 5, and the pressure inside the bellows and the load of the leaf springs 16, 16' oppose each other via the operating rod 14, The operating rod 14 moves in the axial direction due to the difference between the internal pressure of the bellows and the load of the leaf spring, and the movement of the operating rod 14 is transmitted to the switch S, which drives the snap operating plate 11a, thereby causing the reversing spring 12 to move. The contacts 9 and 10 are opened and closed via the movable contact plate 11. To set the operating temperature, with the cam plate 19 of the camshaft 18 set at a constant position, move the adjusting screw 20 back and forth to adjust the sensitivity setting spring part Y for the bellows.
The on-operation value of the switch is determined by adjusting the spring load of the switch.In this case, the adjustment screw 20 is used to almost change the state in which the temperature setting range spring part X and the bellows 4 are balanced (a constant operating temperature value). The proper position of the movable part 4b of the bellows or the operating rod 14 is determined to operate the switch without any need for the switch. The off-point operating temperature is set by moving the adjusting screw 13 back and forth. In this state, it is incorporated into refrigerators, room air conditioners, etc. To set the operating temperature after assembly, the cam shaft 18 is rotated, the cam plate 19 moves the sliding adjustment plate 17, and the drive plate 17a moves the plate spring 16.
This is done by elastically deforming the temperature setting range spring section X together with the auxiliary spring 16'. In this case, the effect changes depending on the width, thickness, number, etc. of the auxiliary springs, but the table below and Figure 8 show that the sensitivity of switch S does not change much even if the temperature setting range increases. show.

[Table] Fig. 9 also shows the U-shaped spring + auxiliary spring system with different wall pressures of the U spring. In the figure, the values at the starting point are different depending on the thickness of the U-shaped spring, but the changes thereafter are almost the same and change at regular intervals. In the embodiments described above, a leaf spring deformed into a U-shape has been described, but the present invention can be similarly applied to a flat leaf spring. As described above, the present invention provides a thermostat that opens and closes a switch based on the operation of a pressure-responsive member such as a bellows. Using a leaf spring, the deformed U-shaped leaf spring is opposed to the pressure-responsive body with the middle part of the long side part, and is folded into an arc shape from the long side part to the short side part on one side of the middle part. The bent auxiliary leaf springs are overlapped to form a temperature setting range spring part, and the operation of the cam means is transmitted to the short side part, and the long side part is connected to the pressure responsive body on the other side of the intermediate part. This is because the spring part is brought into contact with a fulcrum on the opposite side to form a sensitivity setting spring part for setting the difference between on and off of the switch, and a load adjustment screw is engaged with the free end of the long side part. , it is possible to set the temperature over a wide range without reducing the sensitivity of the switch on/off difference, and this is a modified U-shaped leaf spring bent in an arc on one side. It has the advantage that it can be achieved with an extremely simple structure by polymerizing.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention;
Figure 2 is a left side view of the same as above, Figure 3 is a right side view of the same as above, Figure 4 is an internal configuration diagram with front casing _A1 removed, and Figure 5 is a sectional view taken along the line - - of Figure 2. , 6th
The figure is an exploded perspective view of the cam part, FIG.
FIG. 8 is a graph showing the relationship between the set temperature and sensitivity of a leaf spring, and FIG. 9 is a graph showing the relationship between the set temperature and sensitivity of leaf springs having different plate thicknesses in the present invention. 4... Pressure responsive body (bellows), S... Switch, 16... Deformed U-shaped leaf spring, 16a... Arc-shaped bent part, 16b... Long side part, 16c... Short side part,
16'... Auxiliary spring, X... Spring part for temperature setting range, Y... Spring part for sensitivity setting, 15b... Fulcrum,
20...Load adjustment screw.

Claims (1)

[Claims] 1 In a thermostat that opens and closes a switch based on the operation of a pressure-responsive member such as a bellows, a deformed U-shaped leaf spring consisting of a short side and a long side connected via an arcuate bent part is used to prevent the deformation. A U-shaped leaf spring is opposed to the pressure-responsive body with the middle part of the long side, and an auxiliary leaf spring bent in an arc from the long side to the short side is superimposed on one side of the middle part. to form a spring part for the temperature setting range, and transmit the operation of the cam means to the short side, and on the other side of the intermediate part, use the long side as a fulcrum on the opposite side to the pressure responsive body. 1. A thermostat comprising: a spring part for setting sensitivity regarding the on/off difference of a switch; and a load adjusting screw engaged with a free end of the long side part.