Long-service-life electric brush assembly for contact type potentiometer

Abstract

The long-service-life electric brush assembly comprises an insulated electric brush seat and a conductive electric brush, the ellipse-like electric brush is formed by arranging a plurality of annularly closed electric brush wires side by side, the electric brush is arranged on the outer wall of the ellipse-like or ellipse-like electric brush seat, and the electric brush is arranged on the outer wall of the ellipse-like or ellipse-like electric brush seat. Two ends of a short shaft of the electric brush are respectively connected with two ends of a short shaft of the electric brush seat, gaps are reserved between two ends of a long shaft of the electric brush and two ends of a long shaft of the electric brush seat, and the two ends of the long shaft of the electric brush are respectively bent to form electric brush contact parts. The two symmetrical electric brush contact parts at the two ends of the long shaft of the electric brush can provide a push-pull effect when operating in a vibration environment, the friction force of the electric brush contact parts is dispersed to two fulcrums, the electric brush contact parts are not easy to shake, the deformation is small, the electric brush contact parts follow well, the return error is small, the contact stability is good, and the service life of the electric brush is prolonged. Finally, the detection precision or the output voltage control precision of the potentiometer is obviously improved, and the service life is obviously prolonged.

Description

Technical Field

[0001] This utility model relates to a partial structure of a contact potentiometer (sensor), and more particularly to a high-life brush assembly for a contact potentiometer. Background Technology

[0002] Potentiometers (sensors) are classified into two types based on the way they generate electrical signals: contact potentiometers (sensors) and non-contact potentiometers (sensors). Contact potentiometers (sensors) are potentiometers that generate changing electrical signals through mechanical contact. The most common way to generate electrical signals is by having a brush slide in contact with the working strip of a resistive element to generate an electrical signal. For example, common linear displacement potentiometers and angular displacement potentiometers based on conductive plastic resistive elements are this type of contact potentiometer.

[0003] The brush is a key component of a contact potentiometer, and its manufacturing quality directly affects the potentiometer's performance, especially output stability and lifespan. In practical applications, brushes are typically mounted on brush holders and other components to form brush assemblies.

[0004] Traditional contact potentiometers use cantilever brushes, where the end of the brush filament that contacts the resistive element is the cantilever end, requiring support from the other end connected to the brush holder. Cantilever brushes specifically include overhead brushes and horizontal brushes. Regardless of the type, cantilever brushes have the following drawbacks: To ensure reliable contact and prevent disengagement of the brush contacts, the design incorporates a large amount of compression and pressure. However, due to the cantilever structure and single-point support, the contact point is far from the support point, resulting in relatively poor stability and a tendency for contact chatter. This is especially problematic in complex operating conditions such as vibration, which can lead to poor potentiometer performance, such as high and / or large variations in contact resistance, high and / or large variations in sliding noise, large hysteresis error, and short elastic life. Ultimately, this results in low detection accuracy or output voltage control accuracy and a short lifespan for the potentiometer. Utility Model Content

[0005] The purpose of this invention is to provide a long-life brush assembly for contact potentiometers that uses annular brush filaments in order to solve the above-mentioned problems.

[0006] This utility model achieves the above objectives through the following technical solutions:

[0007] A high-life brush assembly for a contact potentiometer includes an insulated brush holder and a conductive brush. The elliptical brush is formed by multiple circumferentially closed brush filaments arranged side by side. The brush is mounted on the outer wall of the elliptical or elliptical brush holder. The two ends of the short axis of the brush are connected to the two ends of the short axis of the brush holder, and a gap is left between the two ends of the long axis of the brush and the two ends of the long axis of the brush holder. The two ends of the long axis of the brush are bent to form brush contact portions. The aforementioned elliptical shape is a shape close to an ellipse. More specifically, this shape includes mutually perpendicular long and short axes, with the two ends of the long axis convex outward and the outer surfaces of the two ends of the long axis transitioning to arc surfaces or bevels. This is a conventional, general definition of an elliptical shape.

[0008] Preferably, in order to stably and reliably connect the brush and the brush holder, the brush holder is a plastic holder, the two ends of the short shaft of the brush are respectively placed outside the two ends of the short shaft of the brush holder, and two metal plates are respectively located outside the two ends of the short shaft of the brush and are respectively connected to the outer wall of the two ends of the short shaft of the brush holder by connecting screws.

[0009] Preferably, in order to connect the brush and the brush holder more stably and reliably, the metal plate is provided with a through hole at the position corresponding to the brush, and the through hole and its surrounding area are provided with solder to realize the fixed connection between the brush and the corresponding metal plate, and the two connecting screws are respectively located on both sides of the solder.

[0010] Preferably, to facilitate the mounting of the brush assembly on the screw for application, the high-life brush assembly for contact potentiometers further includes a nut, which is fixedly mounted in the central through hole of the brush holder.

[0011] Preferably, in order to achieve a reliable connection between the nut and the brush holder, the brush holder is a plastic holder, and the nut and the brush holder are integrally molded together.

[0012] Preferably, in order to facilitate application and realize the anti-rotation connection function between the nut and the brush holder, the nut has protruding nut protrusions on opposite sides in one direction, and the nut protrusions have mounting holes. The brush holder has mounting grooves on one side surface corresponding to the nut protrusions, and the two nut protrusions are respectively placed in the corresponding mounting grooves. The nut has protruding positioning protrusions on opposite sides in the other direction, and the positioning protrusions are embedded in the brush holder.

[0013] Preferably, for ease of application, the brush holder is provided with two guide holes at the two ends of the long shaft.

[0014] The beneficial effects of this utility model are as follows:

[0015] This invention designs an elliptical brush and an elliptical or near-elliptical brush holder, connecting the two ends of the short axis of the brush to the two ends of the short axis of the brush holder, and leaving gaps between the two ends of the long axis of the brush and the two ends of the long axis of the brush holder. The brush contacts at both ends of the long axis contact with other components of the positioner (such as resistors and current collectors). While achieving the function of acquiring changing electrical signals through the two brush contacts, the two symmetrical brush contacts at both ends of the long axis provide a push-pull effect during operation in a vibration environment. The frictional force of the brush contacts is distributed to two support points, reducing chatter, minimizing deformation, and improving the follow-through of the brush contacts. This largely eliminates hysteresis, reduces return error, and enhances contact stability, ultimately significantly improving the potentiometer's detection accuracy or output voltage control accuracy and significantly increasing its service life, enabling it to handle various complex operating conditions. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the high-life brush assembly for contact potentiometers described in this utility model;

[0017] Figure 2 This is a side view of the high-life brush assembly for a contact potentiometer described in this utility model.

[0018] Figure 3 This is a three-dimensional structural diagram of the nut for the high-life brush assembly of a contact potentiometer as described in this utility model.

[0019] Figure 4 This is a schematic diagram of the main cross-sectional structure of the high-life brush assembly for contact potentiometers described in this utility model when applied to a multi-turn angular displacement potentiometer. The brush assembly and the backlash elimination seat are shown in the main view. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings:

[0021] like Figures 1-3As shown, the high-life brush assembly for contact potentiometers of this invention includes an insulated brush holder 1 and a conductive brush 3. The elliptical brush 3 is formed by multiple circumferentially closed brush filaments (not individually marked in the figure, preferably made of precious metal palladium-iridium alloy wire) arranged side by side. The brush 3 is mounted on the outer wall of the elliptical or elliptical brush holder 1. The two ends of the short axis of the brush 3 are connected to the two ends of the short axis of the brush holder 1, and there is a gap between the two ends of the long axis of the brush 3 and the two ends of the long axis of the brush holder 1. The two ends of the long axis of the brush 3 are bent to form brush contact portions 11. The aforementioned elliptical shape is a shape close to an ellipse. More specifically, this shape includes mutually perpendicular long and short axes, with the two ends of the long axis convex outward and the outer surfaces of the two ends of the long axis transitioning to arc surfaces or bevels. This is a conventional general definition of an elliptical shape.

[0022] like Figures 1-4 As shown, this utility model also discloses the following more optimized specific structures:

[0023] To ensure a stable and reliable connection between the brush 3 and the brush holder 1, the brush holder 1 is a plastic holder. The two ends of the short shaft of the brush 3 are respectively placed on the outer sides of the two ends of the short shaft of the brush holder 1. Two metal plates 6 (preferably palladium-iridium alloy plates or palladium-iridium alloy sheets) are respectively located outside the two ends of the short shaft of the brush 3 and are respectively connected to the outer walls of the two ends of the short shaft of the brush holder 1 by connecting screws 8.

[0024] To ensure a more stable and reliable connection between the brush 3 and the brush holder 1, a through hole (not marked in the figure) is provided on the metal plate 6 at the position corresponding to the brush 3, and solder 7 is provided in the through hole and its surrounding area to achieve a fixed connection between the brush 3 and the corresponding metal plate 6. Two connecting screws 8 are located on both sides of the solder 7.

[0025] To facilitate the installation of this brush assembly on the screw for application, the high-life brush assembly for contact potentiometers also includes a nut 4, which is fixedly installed in the central through hole of the brush holder 1.

[0026] To achieve a reliable connection between the nut 4 and the brush holder 1, the brush holder 1 is a plastic holder, and the nut 4 and the brush holder 1 are integrally molded.

[0027] To facilitate application and achieve the anti-rotation connection function between the nut 4 and the brush holder 1, the nut 4 has protruding nut protrusions 10 on opposite sides in one direction. The nut protrusions 10 have mounting holes 9. The brush holder 1 has mounting grooves 5 on one side surface corresponding to the nut protrusions 10, and the two nut protrusions 10 are respectively placed in the corresponding mounting grooves 5. The nut 4 has protruding positioning protrusions 12 on opposite sides in the other direction. The positioning protrusions 12 are embedded in the brush holder 1.

[0028] For ease of use, two guide holes 2 are provided on the brush holder 1 near both ends of the long shaft.

[0029] Combination Figures 1-3 The following describes a preferred method for manufacturing this brush assembly; however, this method is not the only method and is not the subject of protection of this utility model:

[0030] 1. Manufacture the mandrel. The angle of the mandrel should conform to the shape characteristics of the brush 3, i.e., structural symmetry. The included angle design should focus on the free height of the contact point after springback. The included angle of the mandrel in the brush contact part 11 should be smaller than its free state angle, and the free state angle should be smaller than its working state angle. The height of the mandrel in the brush contact part 11 should be greater than its free state height, and the free state height should be greater than its working state height. The mandrel material should be stainless steel with high hardness and no welding characteristics. Its hardness can ensure the bending and forming of the brush 3, and its non-welding characteristics are beneficial for subsequent brush wire tinning and demolding. In addition, the mandrel needs to be easy to manufacture and easy to demold.

[0031] 2. The brush 3 uses a precious metal palladium-iridium alloy wire with high surface hardness and low stiffness ratio in the length direction as the brush wire. This is beneficial to the forming of the brush 3 and maintains the brush contact part 11 with high wear resistance, corrosion resistance and salt spray resistance.

[0032] 3. The brush filaments are wound around the core rod to form the brush filaments. By controlling the tension of the brush filaments, brush filaments with shapes that conform to the core rod can be produced through tight winding.

[0033] 4. After the brush 3 is formed, the mounting part is tinned and fixed with a metal plate 6 made of palladium-iridium alloy to form solder 7. The tinning principle utilizes the capillary principle. When the brush filaments are closely arranged, capillary pores are formed between each brush filament and between the brush filaments and the metal plate 6. When the solder melts, the brush filaments and the metal plate 6 can be welded together through the capillary pores. Since the core rod is not weldable, it can be detached after welding.

[0034] 5. Remove the head and tail of the brush bristles, remove the spindle, and the core rod can be detached, thus obtaining the ideal brush 3.

[0035] 6. Place the brush holder 1, which is integrally molded with the nut 4, into the oval-shaped hole of the brush 3, and connect the two ends of the short shaft of the brush 3 to the two ends of the short shaft of the brush holder 1 respectively. Pass the connecting screws 8 through the corresponding through holes on the metal plate 6 and connect them to the corresponding screw holes on the brush holder 1. After tightening the connecting screws 8, the brush assembly is obtained.

[0036] The specific application of this utility model will be described in detail below with reference to a preferred application scenario:

[0037] like Figures 1-4As shown, when the high-life brush assembly for contact potentiometers described in this utility model is applied to a multi-turn angular displacement potentiometer based on conductive plastic resistive elements, in addition to the brush assembly, the multi-turn angular displacement potentiometer also includes a housing, a drive shaft 23, a resistive element 30, a current collector ring 26, and a connecting guide rod 19, an end plate 18, a lead screw 22, an annular rack 15, a transmission gear, and a backlash elimination seat 27, all placed inside the housing and located between the resistive element 30 and the current collector ring 26. The housing includes a housing base 31, a housing cylinder 13, and a housing cover 14. The two ends of the housing cylinder 13 are respectively connected to the housing base 31 and the housing cover 14 by screws. The annular resistive element 30 is mounted on the inner wall of the housing base 31, and the annular rack 15 is mounted on the inner wall of the housing cylinder 13. Near the housing cover 14, an annular current collector ring 26 is installed on the inner wall of the housing cover 14. The drive shaft 23 passes through the corresponding through hole on the housing cover 14 and is connected by a bearing 20 (Note: In this specific embodiment, the bearing is uniformly marked with 20, but bearings 20 in different positions are not the same bearing, the same below). One end of the drive shaft 23 is connected to the housing seat 31 through the bearing 20. One side surface of the resistor 30 is provided with a working strip (i.e., conductive plastic strip, not shown in the figure). The two ends of the working strip on the resistor 30 are respectively connected to the inner end of the power lead 32. One side surface of the current collector ring 15 is provided with a conductive strip (not shown in the figure). The conductive strip on the current collector ring 26 is connected to the inner end of the signal lead 29. The outer end of the power lead 32 and the outer end of the signal lead 29 are connected to the inner end of the signal lead 29. The outer ends pass through corresponding through holes on the housing cylinder 13 and are placed outside the housing; the annular transmission gear includes a first transmission gear 16 and a second transmission gear 17 arranged in parallel, with a torsion spring 21 installed between the first transmission gear 16 and the second transmission gear 17, forming a backlash-free gear (a backlash-free gear is a conventional combination gear); the outer diameter of the middle section of the drive shaft 23 is increased to form a large-diameter section 25, and the two ends of the two parallel connecting guide rods 19 are respectively connected to the end plate 18. The connecting guide rods 19 are perpendicular to the drive shaft 23, and the middle sections of the two connecting guide rods 19 are connected to the large-diameter section 25 of the drive shaft 23 by pins 24. The lead screw 22 is parallel to the connecting guide rods 19 and is located between the two connecting guide rods 19. The positions of the lead screw 22 near the two ends are... The screw 22 is connected to the two end plates 18 via the bearing 20. The middle section of the screw 22 passes through the corresponding through hole on the large diameter section 25 of the drive shaft 23 and does not contact each other. The first transmission gear 16 and the second transmission gear 17 are fitted outside one end of the screw 22 through their own central through hole and mesh with the ring rack 15. The center line of the transmission gear is perpendicular to the center line of the ring rack 15 and parallel to the center line of the screw 22. The nut 4 is fitted outside the screw 22 and threaded. The two connecting guide rods 19 pass through the two guide through holes 2 on the two brush holders 1 respectively. The two brush contact parts 11 of the brush 3 contact the working strip on the resistor 30 and the conductive strip on the current collector ring 26 respectively. The working strip on the resistor 30 is a multi-turn spiral working strip located on the same plane.The backlash elimination seat 27 has a screw hole in the middle, through which the lead screw 22 passes and is threaded. The backlash elimination seat 27 has two guide holes, through which two connecting guide rods 19 pass respectively. One end of two parallel backlash elimination springs 28 (preferably tension springs) is connected to the mounting holes 9 on the two nut protrusions 10 and placed in the corresponding mounting grooves 5. The other ends of the two backlash elimination springs 28 are connected to the backlash elimination seat 27.

[0038] Combination Figure 4 In use, the outer end of the drive shaft 23 is connected to the drive component of the device to be tested (for detecting angular displacement), or it is used for manual drive rotation (for outputting electrical signals of different voltages). After the drive shaft 23 starts to rotate, it drives the lead screw 22, connecting guide rod 19, end plate 18, transmission gear, brush holder 1, brush 3, backlash elimination seat 27, and backlash elimination spring 28 to rotate synchronously. During the rotation of the transmission gear around the center line of the drive shaft 23, it rotates around the center line of the lead screw 22 due to meshing with the ring rack 15, thereby driving the lead screw 22 to rotate around its own center line. Since the brush holder 1 and the backlash elimination seat 27 are threadedly engaged with the lead screw 22 and cannot rotate on their own, the brush holder 1 and the backlash elimination seat 27 move axially along the lead screw 22. This causes the two brush contact portions 11 of the brush 3 to move in a spiral motion on the working band of the resistor 30 and the conductive band of the current collector ring 15, respectively. The trajectory of this spiral motion is consistent with the spiral shape of the working band of the resistor 30. This consistency can be achieved through reasonable adjustment using existing technology. The brush 3 receives a changing electrical signal and outputs it through the signal lead 29, realizing the corresponding angular displacement detection function or different voltage output function. Because the motion trajectory and working band of the brush 3 are both constant-speed spirals (this spiral is also known as an Archimedean spiral), the rotation angle of the drive shaft 23, i.e., the electrical travel of the potentiometer, can exceed 360° and theoretically can be infinitely large.

[0039] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the technical solutions of this utility model. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of this utility model patent.

Claims

1. A high-life brush assembly for a contact potentiometer, comprising an insulated brush holder and a conductive brush, characterized in that: The elliptical brush is formed by multiple circumferentially closed brush filaments arranged side by side. The brush is mounted on the outer wall of the elliptical or elliptical brush holder. The two ends of the short axis of the brush are connected to the two ends of the short axis of the brush holder, and there is a gap between the two ends of the long axis of the brush and the two ends of the long axis of the brush holder. The two ends of the long axis of the brush are bent to form brush contact portions.

2. The high-life brush assembly for a contact potentiometer according to claim 1, characterized in that: The brush holder is a plastic holder. The two ends of the short shaft of the brush are respectively placed outside the two ends of the short shaft of the brush holder. Two metal plates are respectively located outside the two ends of the short shaft of the brush and are respectively connected to the outer wall of the two ends of the short shaft of the brush holder by connecting screws.

3. The high-life brush assembly for a contact potentiometer according to claim 2, characterized in that: The metal plate has a through hole at the position corresponding to the brush, and solder is provided in the through hole and its surrounding area to achieve a fixed connection between the brush and the corresponding metal plate. The two connecting screws are located on both sides of the solder.

4. The high-life brush assembly for a contact potentiometer according to any one of claims 1-3, characterized in that: The high-life brush assembly for contact potentiometers also includes a nut, which is fixedly installed in the central through hole of the brush holder.

5. The high-life brush assembly for a contact potentiometer according to claim 4, characterized in that: The brush holder is a plastic holder, and the nut is integrally molded with the brush holder.

6. The high-life brush assembly for a contact potentiometer according to claim 5, characterized in that: The nut has protruding nut protrusions on opposite sides in one direction, and mounting holes are provided on the nut protrusions. The brush holder has mounting grooves on one side surface corresponding to the nut protrusions, and the two nut protrusions are respectively placed in the corresponding mounting grooves. The nut has protruding positioning protrusions on opposite sides in the other direction, and the positioning protrusions are embedded in the brush holder.

7. The high-life brush assembly for a contact potentiometer according to any one of claims 1-3, characterized in that: The brush holder has two guide holes located near both ends of the long shaft.

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