Structure for increasing rotation torque and hand feeling of adjusting shaft of liquid expansion type temperature controller

Abstract

A structure for increasing rotation torque and hand feeling of an adjusting shaft of a liquid expansion type temperature controller belongs to the technical field of liquid expansion type temperature controllers, a first convex part and a second convex part which are inverted-V-shaped and protrude upwards are respectively arranged on the front side and the rear side of the middle of a reed, and the vertical center line of the two convex parts and the vertical center line of the reed are collinear and pass through the circle center P; a square hole is formed in the limiting piece with the arc flange, the vertical center line of the square hole passes through the circle center P, the center distance of the square hole is equal to the center distance of the first protrusion, the center distance of the second protrusion is larger than the sum of the center distance of the first protrusion and the side length of the square hole, the length of the first protrusion is larger than the side length of the square hole, and the width of the first protrusion is smaller than the side length of the square hole. By means of the structure, the starting torque of the rotating adjusting shaft in the process from the zero position to the starting position is far larger than the torque during normal temperature adjusting rotation, the sudden change obvious hand feeling is achieved, and when the rotating adjusting shaft is adjusted to be close to the zero position, the rotating adjusting shaft can automatically fall into and be locked at the zero position.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid expansion type temperature controllers, and particularly relates to a structure for increasing the rotation torque and feel of an adjusting shaft of a liquid expansion type temperature controller. Background Art

[0002] Liquid expansion type temperature controllers are widely used in electric heating appliances such as electric water heaters and electric ovens. By sensing the temperature rise and fall inside the box body, their microswitches are turned on and off, thereby controlling the on and off of the electric heating tube to achieve temperature control. Chinese Patent CN205211660U, with the invention name "Liquid expansion type high-current temperature controller", discloses a structure of a liquid expansion type high-current temperature controller. The temperature adjustment mechanism is composed of a ceramic base 10, an adjusting shaft 13 (including an adjusting nut), a fixing plate 15, a limiting piece 6, a leaf spring 5, a locking piece 23, etc. The adjusting shaft 13 and the adjusting nut are in threaded cooperation. When the user rotates the adjusting shaft 13, it can push the diaphragm box 4, and through the lever action of the diaphragm box seat 2, the push rod 3 drives the microswitch to act. The limiting piece 6 limits the rotatable angle of the adjusting shaft 13, and the leaf spring 5 is closely attached to the limiting piece 6 to generate a certain rotational friction torque. It can be seen from the disclosed figure that the leaf spring 5 is provided with 4 evenly distributed convex points in contact with the limiting piece 6, so that the rotational torque within the entire rotatable angle range of the adjusting shaft 13 is consistent. Generally speaking, the design is such that when the adjusting shaft is screwed counterclockwise to the end, it is in the zero position. This position can maintain the off state regardless of the temperature sensed. After that, if the adjusting shaft 13 is screwed clockwise, the operating temperature gradually increases until the maximum operating temperature is reached at the 270° angle position. Sometimes, after using the electric heating appliance, the user needs to screw the knob and the adjusting shaft 13 counterclockwise to the zero position to turn off the power of the electric heating appliance. If it cannot be screwed to the zero position, it may cause the electric heating appliance to operate at a low temperature for a long time, resulting in wasted energy and reduced service life of the electric heating appliance. For this reason, some customers have put forward the need for a certain sudden change in feel when the adjusting shaft rotates from the zero position (or the OFF position) to start working, that is, the starting torque during the process from the zero position to start is much greater than the torque during normal temperature adjustment rotation, and when it is adjusted back close to the zero position, it can automatically enter and lock at the zero position. The temperature adjustment structure of the above-mentioned disclosed patent technical solution cannot meet the requirements of the customers. Summary of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide a structure for increasing the rotation torque and feel of the adjusting shaft of a liquid expansion type temperature controller, which can achieve that the starting torque during the process from the zero position to start is much greater than the torque during normal temperature adjustment rotation, with an obvious sudden change in feel, and when it is adjusted back close to the zero position, it can automatically fall into and lock at the zero position.

[0004] The technical solution proposed by the utility model is as follows:

[0005] A structure for increasing the rotational torque and feel of the adjusting shaft of a liquid expansion type temperature controller, comprising a switch box, a bracket, an adjusting nut, an adjusting shaft, two locking screws, a limiting piece, a locking piece, and a reed. The adjusting nut is threadedly connected to the adjusting shaft. The bracket is fixedly connected to the switch box through the locking screws. The adjusting nut is located in the central holes of the switch box and the bracket and is fixedly connected to the switch box and the bracket. The lower end of the adjusting shaft has an oval cross-section and is movably connected to the central oval groove of the limiting piece. The limiting piece is provided with an arc-shaped flange extending outwards. The inner cavity of the switch box is provided with a limiting block protruding inwards and is in limiting contact connection with the arc-shaped flange. The reed is provided with two symmetrically downward-bent wings and is respectively fixedly connected to the two barbs of the locking piece by clamping. The circular middle part of the reed is provided with a central square hole, and a part of the arc surface is cut off on the rear semi-circular surface to form a straight edge. On the reed beside the middle part of the front side of the central square hole, there is a first convex part in an inverted V shape and protruding upwards. On the reed on the inner side of the middle part of the straight edge, there is a second convex part in an inverted V shape and protruding upwards. On the limiting piece with the same center P as the reed, there is a square hole, and the vertical center line of the square hole passes through the center P. The vertical center lines of the first convex part and the second convex part of the reed are collinear and pass through the center P. The vertical center line of the limiting block passes through the center P. The center distance L1 of the first convex part is equal to the center distance L3 of the square hole. The center distance L2 of the second convex part is greater than the sum of the center distance L3 of the square hole and the side length K1 of the square hole.

[0006] The first convex part and the second convex part of the reed have the same shape and size.

[0007] The length E of the first convex part is longer than the side length K1 of the square hole of the limiting piece. The width K2 of the first convex part is smaller than the side length K1 of the square hole. The height H3 of the first convex part is smaller than the thickness B1 of the limiting piece. The symmetric included angle θ between the two inclined surfaces of the first convex part is within the range of 90° to 150°.

[0008] Compared with the prior art, the utility model has the following beneficial effects:

[0009] Based on the existing liquid expansion type thermostat, the utility model is provided with two inverted V-shaped and upward protruding first convex parts and second convex parts with different center distances on the reed. A square hole is opened on the limiting piece with the same center P as the reed. The vertical center lines of the first convex part, the second convex part, the square hole, and the vertical center line of the switch box limiting block are all located in the same vertical plane passing through the center P. The center distance of the square hole is equal to the center distance of the first convex part, and the center distance of the second convex part is greater than the sum of the center distance of the square hole and the side length of the square hole. The length of the first convex part is greater than the side length of the square hole, and the width of the first convex part is less than the side length of the square hole. In the process from the zero position to the start, the starting torque of this structure is much greater than the torque during normal temperature adjustment rotation, with an obvious feeling of mutation. Moreover, when it is adjusted back close to the zero position, it can automatically fall into and lock at the zero position. At the same time, it also has the positive effects of energy saving and extending the service life of electric heating appliances. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is the main sectional view schematic diagram of the structure for increasing the rotation torque and feel of the adjusting shaft of a liquid expansion type thermostat of the utility model.

[0011] Figure 2 is Figure 1 the upward view schematic diagram.

[0012] Figure 3 is Figure 1 the top view schematic diagram of the limiting piece shown in

[0013] Figure 4 is Figure 1 the top view schematic diagram of the reed shown in

[0014] Figure 5 is Figure 4 the main view schematic diagram of the reed shown in

[0015] Figure 6 is the schematic diagram of the mutual action between the first convex part of the reed and the square hole of the limiting piece, showing the process of the square hole sliding into the first convex part in the figure.

[0016] Figure 7 is the schematic diagram of the mutual action between the first convex part of the reed and the limiting piece, showing that the square hole has not yet slid into the first convex part in the figure. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present utility model will be further elaborated in detail through the following embodiments.

[0018] Refer to Figures 1 to 7As shown in the figure, a structure for increasing the rotation torque and feel of the adjusting shaft of a liquid expansion type temperature controller includes a switch box 1, a bracket 2, an adjusting nut 3, an adjusting shaft 4, two locking screws 5, a limiting piece 6, a locking piece 7, and a reed piece 8. The adjusting nut 3 is threadedly connected to the adjusting shaft 4. The bracket 2 is fixedly connected to the switch box 1 through the locking screws 5. The adjusting nut 3 is located in the central holes of the switch box 1 and the bracket 2 and is fixedly connected to the switch box 1 and the bracket 2. The lower end 4-1 of the adjusting shaft 4 has an oval cross-section and is movably connected to the central oval groove 6-1 of the limiting piece 6. The limiting piece 6 is provided with an arc-shaped flange 6-2 extending outward. The inner cavity of the switch box 1 is provided with a limiting block 1-2 protruding inward and is in limiting contact connection with the arc-shaped flange 6-2. The reed piece 8 is provided with two symmetrically downward-bent wings 8-1, which are respectively fixedly connected to the two barbs 7-1 of the locking piece 7 by clamping. The circular middle part of the reed piece 8 is provided with a central square hole 8-4, and a part of the arc surface is cut off on the rear semi-circular surface to form a straight edge 8-5. On the reed piece 8 beside the middle part 8-4-1 of the front side of the central square hole 8-4, there is a first convex part 8-2 in an inverted V shape and protruding upward. On the reed piece 8 on the inner side of the middle part of the straight edge 8-5, there is a second convex part 8-3 in an inverted V shape and protruding upward. On the limiting piece 6 with the same center P as the reed piece 8, there is a square hole 6-3. The vertical center line of the square hole 6-3 passes through the center P. The vertical center lines of the first convex part 8-2 and the second convex part 8-3 of the reed piece 8 are collinear and pass through the center P. The vertical center line of the limiting block 1-2 passes through the center P. The center distance L1 of the first convex part 8-2 is equal to the center distance L3 of the square hole 6-3. The center distance L2 of the second convex part 8-3 is greater than the sum of the center distance L3 of the square hole 6-3 and the side length K1 of the square hole 6-3.

[0019] The first convex part 8-2 and the second convex part 8-3 of the reed piece 8 are the same in shape and size.

[0020] The length E of the first convex part 8-2 is longer than the side length K1 of the square hole 6-3 of the limiting piece 6. The width K2 of the first convex part 8-2 is smaller than the side length K1 of the square hole 6-3. The height H3 of the first convex part 8-2 is smaller than the thickness B1 of the limiting piece 6. The symmetric included angle θ of the two inclined surfaces of the first convex part 8-2 is within the range of 90° to 150°.

[0021] The limiting piece 6 is provided with an arc-shaped flange 6-2, which can only rotate within an angle range of less than 360° blocked by the limiting piece 1-2 of the switch box 1. The total rotation angle of this embodiment is 270°. The two wings 8-1 of the reed piece are bent downward. The height H1 from the top of the convex part to the wing in the free state is greater than the height H2 after being installed and clamped.

[0022] The liquid expansion type thermostat further includes a temperature sensing component composed of a bellows, a capillary tube, and a temperature sensing cylinder. The bellows is installed on the bearing plate (not shown in the figure). The top of the bellows is pushed by the lower end 4-1 of the adjusting shaft and drives the on-off action of the switch component 1-1 through a push rod. Adjusting the position of the adjusting nut 3 at the factory can change the up and down position of the adjusting shaft 4 to set the operating temperature.

[0023] The working principle and process of this structure are as follows:

[0024] Under the elastic force of the reed 8, when the adjusting shaft 4 is at the zero position, the first convex 8-2 completely falls into the square hole 6-3. When the adjusting shaft 4 drives the limit piece 6 to start from the zero position (rotate clockwise), the square hole 6-3 of the limit piece needs to climb out along the first inclined surface 8-2-1 of the first convex 8-2. Therefore, a relatively large starting torque is required, that is, the hand feeling is heavy. After starting, during the rotation process, both the first convex 8-2 and the second convex 8-3 are elastically frictionally contact-connected with the limit piece 6. The elastic contact force Fn1 of the first convex 8-2 and the elastic contact force Fn2 of the second convex 8-3 are both perpendicular to the rotation direction of the adjusting shaft 4, and their rotation torques are both small. When the adjusting shaft 4 drives the limit piece 6 to rotate until the first inclined surface 8-2-1 of the first convex 8-2 contacts the first side 6-3-1 of the square hole 6-3, the elastic contact force Fn1 of the reed 8 generates a horizontal component force Fx1 on the first side 6-3-1, pushing the square hole 6-3 of the limit piece to automatically slide into the first convex 8-2, and the adjusting shaft 4 automatically rotates to the zero position. Since the center distance of the second convex 8-3 is larger than the center distance of the first convex 8-2 by more than the side length K1 of the square hole 6-3, the second convex 8-3 will not fall into the square hole 6-2 during the rotation process. Since the area of the reed part where the first convex 8-2 is located is relatively large and the elastic force Fn1 is relatively large, but the center distance L1 is relatively small; the area of the reed part where the second convex 8-3 is located is relatively small and the elastic force Fn2 is relatively small, but the center distance L2 is relatively large. Therefore, the torques of the two are basically balanced, Fn1*L1≈Fn2*L2, and the limit piece 6 operates smoothly during the rotation process and will not tilt and cause jamming.

[0025] In this embodiment, the reed 8 is processed from a stainless steel spring sheet with a thickness B1 = 0.5mm, H1 = 4.5mm, H2 = 3mm. The V-shaped angle θ of the first convex 8-2 is 120°, the height H3 of the first convex 8-2 is 0.7mm, the length E is 3mm, the width K2 is 1.2mm, the side length K1 of the square hole 6-3 of the limit piece 6 is 1.5mm, and the thickness B1 of the limit piece 6 is 1mm.

[0026] Measured results: The starting torque is 16 Ncm, and the rotation torque is 6 Ncm. It can be seen that the starting torque during the process of rotating the adjusting shaft from the zero position to the start is much greater than the rotation torque during normal temperature adjustment, and there is a sudden heavy hand feeling.

Claims

1. A structure for increasing the rotational torque and hand feel of an adjusting shaft of a liquid expansion thermostat, comprising a switch box (1), a bracket (2), an adjusting nut (3), an adjusting shaft (4), two locking screws (5), a limit plate (6), a locking plate (7), and a spring plate (8), wherein the adjusting nut (3) and the adjusting shaft (4) are threadedly connected, the bracket (2) is fixedly connected to the switch box (1) by the locking screw (5), and the adjusting nut (3) is located in a center hole of the switch box (1) and a center hole of the bracket (2) and is fixedly connected to the switch box (1) and the bracket (2). The lower end portion (4-1) of the adjustment shaft (4) is an oblate cross section and is movably connected to the central oblate groove (6-1) of the limit plate (6); the limit plate (6) is provided with an arc flange (6-2) extending outward; the inner cavity of the switch box (1) is provided with an inwardly protruding limit block (1-2) and is in contact with the arc flange (6-2); the spring leaf (8) is provided with two symmetrical, downwardly bent wings (8-1) and are respectively fixedly connected to the two barbs (7-1) of the locking plate (7), characterized in that: A central square hole (8-4) is provided in the circular middle of the reed (8), and a portion of the arc surface is cut off on the rear semicircular surface to form a straight edge (8-5), a first convex part (8-2) in an inverted V shape and protruding upward is provided on the reed (8) beside the middle of the front edge (8-4-1) of the central square hole (8-4), a second convex part (8-3) in an inverted V shape and protruding upward is provided on the reed (8) inside the middle of the straight edge (8-5), and a square hole (6-3) is provided on the limit plate (6) which is coaxial with the reed (8) ), the vertical center line of the square hole (6-3) passes through the center P of the circle, the vertical center line of the first protrusion (8-2) of the spring sheet (8) and the vertical center line of the second protrusion (8-3) are colinear and pass through the center P of the circle, the vertical center line of the limit block (1-2) passes through the center P, the center distance L1 of the first protrusion (8-2) is equal to the center distance L3 of the square hole (6-3), and the center distance L2 of the second protrusion (8-3) is greater than the sum of the center distance L3 of the square hole (6-3) and the side length K1 of the square hole (6-3).

2. According to claim 1, the structure of the liquid expansion thermostat for increasing the rotation torque and feel of the regulating shaft is characterized by: The first protrusion (8-2) and the second protrusion (8-3) of the reed (8) are of the same shape and size.

3. According to claim 1, the structure of the liquid expansion thermostat for increasing the rotation torque and feel of the regulating shaft is characterized by: The length E of the first protrusion (8-2) is longer than the side length K1 of the square hole (6-3) of the limiting plate (6), the width K2 of the first protrusion (8-2) is smaller than the side length K1 of the square hole (6-3), the height H3 of the first protrusion (8-2) is smaller than the thickness B1 of the limiting plate (6), and the symmetrical angle θ between the two inclined surfaces of the first protrusion (8-2) is equal to an angle range of 90° to 150°.

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