CN118316256A - DC motor with sensor - Google Patents
DC motor with sensor Download PDFInfo
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- CN118316256A CN118316256A CN202310021867.4A CN202310021867A CN118316256A CN 118316256 A CN118316256 A CN 118316256A CN 202310021867 A CN202310021867 A CN 202310021867A CN 118316256 A CN118316256 A CN 118316256A
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- sensor
- motor
- direct current
- metal
- current motor
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- 239000002184 metal Substances 0.000 claims abstract description 65
- 238000004804 winding Methods 0.000 claims abstract description 18
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000003990 capacitor Substances 0.000 claims description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 13
- 229910052799 carbon Inorganic materials 0.000 claims description 13
- 210000000078 claw Anatomy 0.000 claims description 7
- 230000003287 optical effect Effects 0.000 claims description 4
- 239000002826 coolant Substances 0.000 claims description 3
- 239000010687 lubricating oil Substances 0.000 claims description 3
- 230000005611 electricity Effects 0.000 claims description 2
- 230000002411 adverse Effects 0.000 abstract description 4
- 230000005540 biological transmission Effects 0.000 abstract description 4
- 230000004048 modification Effects 0.000 description 7
- 238000012986 modification Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 4
- 230000003071 parasitic effect Effects 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000004904 shortening Methods 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 238000010891 electric arc Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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Abstract
The invention provides a direct current motor with a sensor, which comprises a stator, a rotor, a reversing system, the sensor and a metal shell, wherein a stator winding in the stator or a rotor winding in the rotor and the reversing system form a motor loop, the sensor is positioned in the direct current motor and is electrically independent from the motor loop, no direct connection exists between the sensor and the motor loop, and a conductive connection is arranged between a lead wire of the sensor and the metal shell. The direct current motor with the sensor provided by the invention can reduce the transmission of electromagnetic interference along the power wire harness by intercepting the electromagnetic interference on the sensor loop, so that other electrical equipment connected with the direct current motor in a system cannot be adversely affected.
Description
[ Field of technology ]
The present invention relates to a dc motor, and more particularly, to a dc motor with a sensor.
[ Background Art ]
Electromagnetic interference (EMI) is the radiation or conduction of electromagnetic noise on a system. As with most electromagnetic circuit assemblies, dc motors are a common source of EMI, in which electromagnetic interference is generated and emitted outside the motor due to the periodic interruption of the current in the windings. In a brushed dc motor, the main source of EMI is the arc discharge generated by the continuous commutation of the carbon brushes of the motor and the commutator. EMI sources are potential sources of noise that can produce common mode currents. EMI may cause performance degradation of other electrical devices powered in the same system, data corruption, or complete system failure if EMI is strong enough.
The prior art dc motor comprises a stator (winding), a rotor (winding), a commutation system and a sensor system, wherein the stator winding or the rotor winding and the commutation system form a motor loop. The sensor system comprises one or more sensors and positive and negative leads of the sensors, wherein the sensors and the positive and negative leads of the sensors form a sensor loop, and the one or more sensors are, for example, hall sensors or optical sensors and are used for sensing the rotation of the motor and outputting voltage signals representing the rotation distance of the motor; and the temperature sensor is used for sensing the temperature of the parts such as a motor winding, a bearing, lubricating oil, a cooling medium and the like so as to know the running condition of the motor and perform necessary protection.
Those skilled in the art are generally concerned with conducted emissions along the motor power line in dc motors (up to 30M to 120 MHz), and since the motor loop and the sensor loop are electrically independent and there is no direct connection between them, the effect of EMI generated by the motor on the sensor loop when the sensor loop is located near the EMI source, and the interference on the motor power line after electromagnetic interference returns, have not been found.
Through extensive research and testing, the inventors of the present application have found that due to the space limitations of the dc motor, the motor loop and the sensor loop are close to each other, and that when the sensor loop is located near the EMI source, there are the following problems: the motor-generated EMI is coupled to the sensor loop and this EMI returns to the motor loop to increase the externally conducted emissions.
Referring to fig. 1, a prior art brushed dc motor 10A having a hall sensor is shown that includes a stator (not shown), a rotor (not shown), a commutation system (partially shown), a sensor system (partially shown), a metal housing 12, and a connector 14. The commutation system includes carbon brushes 16, a brush holder 18 and a commutator (not shown). The sensor system includes a hall sensor 20 and a magnetic ring (not shown). Wherein, the Hall sensor 20 is installed on the brush holder 18, is used for sensing the rotation of the motor, and outputs the voltage signal representing the movement stroke of the motor; the connector 14 is fixed to the outer wall of the metal housing 12 and electrically connects the carbon brush 16 and the hall sensor 20, and is connected to an external controller 24 through a sensor harness 22 and to an external power and supply device 28 through a power harness 26, wherein a parasitic capacitance (Cp) exists between the sensor harness 22 and a common ground system (GND).
During operation of the brushed dc motor 10A, each time a commutation occurs, the carbon brush 16 will leave one segment of the commutator and contact the next segment, resulting in a high transient voltage (arcing) and EMI.
In the brushed dc motor 10A, the hall sensor 20 and its positive and negative leads form a sensor loop. The windings of the rotor in the brushed dc motor 10A and the commutation system form a motor loop. Wherein, the motor loop and the sensor loop are electrically independent, and are not directly connected. The inventors of the present application have found that, due to space constraints inside the motor, the motor loop and the sensor loop are close to each other, the spatial distance between the motor loop and the sensor loop is extremely short, electromagnetic energy is easily transferred to each other, and EMI due to transient high voltage generated by commutation is closely coupled to the sensor loop. This coupling occurs internally to the motor and EMI coupled to the sensor circuit is transmitted through the connector 14 to the sensor harness 22 external to the motor. The EMI along the sensor loop will couple to the common ground system (GND) due to parasitic capacitance (Cp) between the sensor harness 22 and the common ground system (GND), and then to the external power and supply device 28, and back into the motor interior through the power harness 26, resulting in increased EMI on the power harness 26, which was noted by the inventors and has been confirmed in several experiments.
Since the influence of EMI generated in the dc motor on the amount of electromagnetic interference on the power harness of the dc motor through the sensor circuit (which is described in the prior art document is not found) is not found by those skilled in the art, the problem caused by the influence is not solved correspondingly in the prior art.
Accordingly, there is a need for an improvement over existing dc motors with sensors to solve the above-described problems of the prior art.
[ Invention ]
The invention aims to provide a direct current motor with a sensor, which can reduce the transmission of electromagnetic interference along a power wire harness of the direct current motor by intercepting electromagnetic interference on a sensor loop, so that other electric equipment connected with the direct current motor in a system is not adversely affected.
In order to achieve the above object, the present invention provides a direct current motor with a sensor, comprising a stator, a rotor, a commutation system, the sensor and a metal casing, wherein a stator winding in the stator or a rotor winding in the rotor and the commutation system form a motor loop, the sensor and the motor loop are electrically independent, and no direct connection exists between the sensor and the motor loop, wherein a conductive connection is arranged between a lead wire of the sensor and the metal casing.
In one embodiment, an electrically conductive connection is provided between the negative lead of the sensor and the metal housing.
In one embodiment, the conductive connection is made between the negative lead of the sensor and the metal housing by a wire or lead.
In one embodiment, the conductive connection is made between the negative lead of the sensor and the metal housing by a series capacitor connection.
In one embodiment, the conductive connection is made between the positive lead of the sensor and the metal housing by a series capacitor connection.
In one embodiment, the sensor is a hall sensor or an optical sensor for sensing the rotation of the motor and outputting a voltage signal representing the rotation distance of the motor; or a temperature sensor for sensing the temperature of the motor windings, bearings, lubricating oil, cooling medium, etc.
In an embodiment, the direct current motor is a brushed direct current motor, which further comprises a connector connected with the metal shell, wherein the reversing system comprises a carbon brush, a brush holder and a reverser, the reverser is fixed on a main shaft of the rotor, the carbon brush, the reverser and an armature winding of the rotor form the motor loop, wherein the sensor is used for sensing the rotation of the motor and outputting a voltage signal representing the movement stroke of the motor, and the sensor and a lead thereof form a sensor loop, wherein the sensor loop is electrically isolated from the motor loop, no direct electrical connection exists between the sensor loop and the motor loop, and the connector is fixed on the outer wall of the metal shell and electrically connects the carbon brush and the lead of the sensor, is connected with an external controller through a sensor wire harness, and is connected with external electricity utilization and power supply equipment through a power wire harness.
In an embodiment, in the case that the positive lead or the negative lead of the sensor is connected to the metal casing through a series capacitor to achieve the conductive connection, the direct current motor further includes a metal grounding spring, the metal grounding spring includes a plurality of elastic claws, wherein the series capacitor is mounted on the brush holder, one end of the series capacitor is connected to the positive lead or the negative lead of the sensor, the other end of the series capacitor is connected to the metal grounding spring, one or more elastic claws of the plurality of elastic claws of the metal grounding spring are fixed on the brush holder, and the other one or more elastic claws are pressed on the metal casing.
In one embodiment, the negative lead of the sensor is connected to the metal housing through a metal spring to achieve the conductive connection, the metal spring is mounted between the connector and the metal housing, one end of the metal spring is connected to the negative lead of the sensor located in the connector, and the other end of the metal spring is sprung against the metal housing.
In one embodiment, the sensor is mounted on the brush holder.
In one embodiment, the sensor is mounted within the brushed DC motor adjacent to the connector.
Compared with the prior art, the technical scheme of the invention realizes the following beneficial technical effects:
1. In a DC motor with a sensor (particularly a brush DC motor), electromagnetic interference on a sensor loop can be intercepted by arranging conductive connection between a lead wire of the sensor and a metal shell of the DC motor, so that the transmission of the electromagnetic interference along a power wire harness of the DC motor is reduced, and adverse effects on other electrical equipment connected with the DC motor in a system are avoided.
2. In a brushed direct current motor having a sensor and a connector, the sensor is mounted within the brush direct current motor at a position adjacent to the connector, thereby shortening the length of the sensor leads within the motor and significantly reducing the amount of coupling of EMI generated in the motor loop to the sensor loop.
[ Description of the drawings ]
Fig. 1 is a schematic structural diagram of a brush direct current motor with a hall sensor according to the prior art.
Fig. 2 is a schematic structural view of a brush direct current motor having a hall sensor according to a first embodiment of the present invention.
Fig. 3 is a schematic structural view of a brush direct current motor having a hall sensor according to a second embodiment of the present invention.
[ Detailed description ] of the invention
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Through extensive research and testing, the inventors of the present application have found that not only is the motor loop and the sensor loop in close proximity to each other due to the space limitations of the dc motor, but also the EMI generated by the dc motor is coupled to the sensor loop, and this EMI is returned to the motor loop to increase the external conduction emission of the EMI along the power harness of the motor. Furthermore, the inventors have found that EMI generated by a direct current motor is coupled to a sensor circuit, and that the problem of increased external conduction emission of EMI along a power harness of the motor is related to the mounting manner of a sensor and the length of the sensor harness, and that the longer the sensor harness is, the greater the parasitic capacitance (Cp) between the sensor harness and a common ground system (GND) is, the easier the EMC coupled to the sensor circuit and transmitted to the sensor harness is conducted to the common ground system (GND) through the parasitic capacitance (Cp), and further reaches external power and power supply equipment connected to the common ground system (GND), and returns to the inside of the motor through the power harness connected to the external power and power supply equipment, resulting in an increased conduction amount of electromagnetic interference on the power harness. Accordingly, the inventors have proposed a technical solution of the present application to solve the above-identified problems.
Specific implementations of the technical solution of the present invention are described in detail below with reference to specific embodiments.
Fig. 2 shows a brushed dc motor 10B having hall sensors according to a first embodiment of the present invention, which includes a stator (not shown), a rotor (not shown), a commutation system (partially shown), a sensor system (partially shown), a metal housing 12, and a connector 14. The commutation system comprises, among other things, a carbon brush 16, a brush holder 18 and a commutator (not shown). The sensor system includes a hall sensor 20 and a magnetic ring (not shown). The hall sensor 20 is mounted on the brush holder 18 for sensing motor rotation and outputting a voltage signal indicative of a motor movement stroke. The connector 14 is fixed on the outer wall of the metal shell 12 and electrically connects the carbon brush 16 and the hall sensor 20, and is connected with an external controller 24 through a sensor wire harness 22 and is connected with an external power utilization and supply device 28 through a power wire harness 26, wherein a conductive connection 30 is arranged between the negative lead of the hall sensor 20 and the metal shell 12, and the conductive connection 30 is a wire or a guide sheet.
Fig. 3 shows a brushed dc motor 10C having a hall sensor according to a second embodiment of the present invention. The structure of the brush direct current motor 10C is substantially the same as that of the brush direct current motor 10B according to the first embodiment of the present invention, and the difference is that: in the brushed dc motor 10C, the hall sensor 20 is installed inside the brushed dc motor 10C at a position close to the connector 14, thereby shortening the lead length of the hall sensor 20 inside the motor
In the case of the first variant of the first embodiment or of the second embodiment (not shown), the electrically conductive connection is made between the negative lead of the hall sensor 20 and the metal housing 12 by means of a series capacitor connection.
In the case of the application of the second variant of the first or second embodiment (not shown), the electrically conductive connection is achieved by a series capacitor connection between the negative lead of the hall sensor 20 and the metal housing 12. The brushed dc motor 10B or 10C further includes a metal grounding spring plate, which includes a plurality of spring fingers, wherein the series capacitor is mounted on the brush holder 18, one end of the series capacitor is connected to the negative lead of the hall sensor 20, and the other end of the series capacitor is connected to the metal grounding spring plate, wherein one or more spring fingers of the plurality of spring fingers of the metal grounding spring plate are fixed on the brush holder 18, and the other spring finger or fingers are spring-pressed on the metal housing 12.
In the application scenario (not shown) of the third modification of the first embodiment or the second embodiment, the conductive connection is achieved between the negative lead of the hall sensor 20 and the metal housing 12 through a metal spring piece, and the metal spring piece is mounted between the connector 14 and the metal housing 12, one end of the metal spring piece is connected to the negative lead of the hall sensor 20 located in the connector 14 (the negative lead of the hall sensor 20 is connected to the connector 14), and the other end of the metal spring piece is sprung against the metal housing 12.
According to a third embodiment (not shown) of the present invention, there is provided a brushed dc motor having a hall sensor, the structural composition of which is substantially the same as that of the brushed dc motor 10B or 10C having a hall sensor according to the first embodiment (including modifications) or the second embodiment (including modifications) of the present invention, the difference between them being that: in the brushed dc motor with hall sensor according to the third embodiment of the present invention, an electrically conductive connection is provided between the positive lead (non-negative lead) of the hall sensor and the metal housing 12 through a series capacitor.
In the application scenario of the first modification of the third embodiment (not shown), the brushed dc motor further includes a metal grounding spring, and the metal grounding spring has the same structure as the metal grounding spring in the application scenario of the first embodiment or the second modification of the second embodiment.
In the brushed dc motors according to the first to third embodiments and their respective variants of the present invention, the hall sensor and its leads constitute a sensor loop. The carbon brush, commutator and armature winding of rotor in the brush DC motor form the motor loop. Because the negative lead or the positive lead of the Hall sensor is electrically connected with the metal shell, electromagnetic interference on a sensor loop can be intercepted, and the transmission of the electromagnetic interference along a power wire harness is further reduced, so that adverse effects on other electrical equipment connected with a direct current motor in a system can be avoided.
In the brushed direct current motor according to the second or third embodiment and the respective modifications thereof, by installing the hall sensor inside the brushed direct current motor at a position close to the connector, the lead length of the hall sensor inside the motor is shortened, and the coupling amount of EMI generated in the motor circuit to the sensor circuit is significantly reduced.
It will be apparent to those skilled in the art that the present invention is not limited to a brushed dc motor, but is equally applicable to a brushless dc motor that generates EMI, provided that there is electromagnetic interference generated by the motor loop within the brushless dc motor that is coupled to the sensor loop.
It will be apparent to those skilled in the art that the present invention is not limited to dc motors having hall sensors, but is equally applicable to dc motors having other types of sensors (e.g., optical sensors, temperature sensors, etc.), provided that the sensors within the dc motor are located near the EMI source, there is a case where electromagnetic interference generated by the motor loop is coupled to the sensor loop.
The above description is only illustrative of the embodiments of the present invention and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.
Claims (11)
1. The utility model provides a direct current motor with sensor, includes stator, rotor, switching-over system, sensor and metal casing, stator winding in the stator or rotor winding in the rotor with the switching-over system has formed the motor return circuit, the sensor is located direct current motor is inside and with the motor return circuit is electrically independent, does not have direct connection between the two, its characterized in that is equipped with conductive connection between the lead wire of sensor with the metal casing.
2. The direct current motor of claim 1, wherein an electrically conductive connection is provided between the negative lead of the sensor and the metal housing.
3. A direct current motor according to claim 2, characterized in that the conductive connection is made between the negative lead of the sensor and the metal casing by means of a wire or a guide piece.
4. The direct current motor according to claim 2, wherein said conductive connection is made between said negative lead of said sensor and said metal housing by a series capacitor connection.
5. The direct current motor according to claim 1, wherein said conductive connection is made between a positive lead of said sensor and said metal housing by a series capacitor connection.
6. The direct current motor according to any one of claims 1 to 5, characterized in that the sensor is a hall sensor or an optical sensor for sensing the motor rotation and outputting a voltage signal representing the motor rotation distance; or a temperature sensor for sensing the temperature of the motor windings, bearings, lubricating oil, cooling medium, etc.
7. The dc motor as set forth in any one of claims 1 to 5, wherein the dc motor is a brushed dc motor further comprising a connection to the metal housing
The connector is provided with a plurality of connecting holes,
Wherein the reversing system comprises a carbon brush, a brush holder and a reverser, the reverser is fixed on a main shaft of the rotor, the carbon brush, the reverser and an armature winding of the rotor form the motor loop,
Wherein the sensor is used for sensing the rotation of the motor and outputting a voltage signal representing the movement stroke of the motor, and the sensor and the lead thereof form a sensor loop,
Wherein the sensor circuit is electrically isolated from the motor circuit without direct electrical connection therebetween,
The connector is fixed on the outer wall of the metal shell, electrically connects the carbon brush with the lead of the sensor, is connected with an external controller through a sensor wire harness, and is connected with external electricity utilization and power supply equipment through a power wire harness.
8. The direct current motor according to claim 7, wherein in case of the conductive connection between the positive or negative lead of the sensor and the metal housing via a series capacitor, the direct current motor further comprises a metal grounding spring plate comprising a plurality of spring fingers,
Wherein, the series capacitor is arranged on the brush holder, one end of the series capacitor is connected with the positive lead or the negative lead of the sensor, the other end is connected with the metal grounding spring plate,
One or more elastic claws of the plurality of elastic claws of the metal grounding elastic sheet are fixed on the brush frame, and the other one or more elastic claws are pressed on the metal shell.
9. The direct current motor according to claim 7, wherein said conductive connection is achieved by a metal spring plate connected between said negative lead of said sensor and said metal housing, said metal spring plate being mounted between said connector and said metal housing with one end connected to said negative lead of said sensor located within said connector and the other end sprung against said metal housing.
10. The direct current motor of claim 7, wherein said sensor is mounted on said brush holder.
11. The direct current motor of claim 7, wherein the sensor is mounted inside the brushed direct current motor at a location proximate to the connector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310021867.4A CN118316256A (en) | 2023-01-06 | 2023-01-06 | DC motor with sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310021867.4A CN118316256A (en) | 2023-01-06 | 2023-01-06 | DC motor with sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118316256A true CN118316256A (en) | 2024-07-09 |
Family
ID=91722793
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310021867.4A Pending CN118316256A (en) | 2023-01-06 | 2023-01-06 | DC motor with sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118316256A (en) |
-
2023
- 2023-01-06 CN CN202310021867.4A patent/CN118316256A/en active Pending
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