Contactor comprising an electric motor and a commutator-brush system

Abstract

The invention relates to a contactor comprising a motor (2) and a commutator-brush system (3), the motor comprising a stator (200) and a rotor (201), the commutator-brush system comprising: - a commutator (300) joined to the rotor, the commutator comprising at least one conductive portion (302) and at least one non-conductive portion (303); and - a pair of brushes formed by two brushes (304), the brushes each having a contact face configured to rub against the commutator. A side surface of the commutator (300) includes the conductive portion (302) and the non-conductive portion (303) of the commutator, the commutator being rotatable about an axis of rotation (X). The commutator-brush system (3) is configured to move between a conducting position in which the commutator electrically connects the pair of brushes, and an interrupting position in which the commutator electrically isolates the pair of brushes (304), the commutator-brush system passing from the conducting position to the interrupting position, and vice versa, by rotation of the commutator (300) by the motor.

Description

DESCRIPTION Title of the invention: Contactor comprising an electric motor and a collector-brush system

[0001] The invention relates to the field of contactors, in particular contactors which have to operate in severe vibratory environments.

[0002] Electrical contactors generally consist of a lever or a blade allowing, depending on their position, electrical contact or electrical isolation, by the limited rotational movement of the lever. Other types of electrical contacts use the translation of two conductive parts. Other types of contact use the rotation of a selector bringing tracks into contact with blades, such as the rotary contactor described in French patent application FR 2407562.

[0003] The disadvantage of these systems is the intrinsic sensitivity of the contact elements (such as levers, blades) to shocks, vibrations and accelerations, which can create translational or rotational movements breaking or creating an electrical contact.

[0004] One solution to this problem is to increase the contact holding force. However, this would require more power to switch the contacts, especially when the contactor has to switch a large number of contacts.

[0005] The invention aims to provide a contactor capable of operating in severe vibration environments without requiring high power to switch the contacts.

[0006] The invention proposes for this purpose a contactor comprising an electric motor and a collector-brush system. The motor is configured to be fixed to a frame and comprises a coaxial stator and rotor. The rotor is configured to be movable in rotation about an axis of rotation. The collector-brush system comprises: a collector assembled to the rotor of the electric motor, the collector having a cylindrical shape and comprising at least one conductive portion and at least one non-conductive portion; and a pair of brushes formed by two brushes, said brushes being configured to be fixed to the frame and each having a contact face configured to rub against the collector.

[0007] According to the invention, a lateral surface of the collector comprises said at least one conductive portion and said at least one non-conductive portion of the collector. The collector is rotatable about the axis of rotation. The collector-brush system is configured to move between a conduction position in which the collector electrically connects the pair of brushes, and an interruption position in which the collector electrically isolates the pair of brushes. At least one conductive portion is in contact with the brushes and no non-conductive portion extends between the two brushes when the collector-brush system is in the conduction position, and a non-conductive portion is in contact with at least one of the brushes of the pair of brushes or a non-conductive portion extends between the two brushes of the pair of brushes when the collector-brush system is in the interruption position. The collector-brush system moves from the conduction position to the interruption position, and vice versa, by rotation of the collector around the axis of rotation under the action of the electric motor.

[0008] The resulting contactor has reduced sensitivity to vibrations from its rotating configuration. The symmetrical structure of the motor, particularly its rotor, and the way the commutator is mounted on the rotor make it possible to obtain a balanced contactor. This balancing prevents shocks or vibrations from moving the commutator, particularly its contacts formed by the pairs of brushes.

[0009] Furthermore, low electrical power is required to switch from the conduction position to the interruption position and vice versa, due to the low friction torque of the brushes on the commutator. This makes it possible to consider the simultaneous control of several contacts with reduced power to supply the contactor.

[0010] Particularly convenient preferred features of the contactor according to the invention are presented below.

[0011] The same conductive portion is in contact with both brushes of the brush pair when the collector-brush system is in the conduction position, and at at least one non-conductive portion is in contact with at least one brush of the pair of brushes when the collector-brush system is in the interrupted position.

[0012] The collector comprises at least two conductive portions, an empty space separating two adjacent conductive portions and forming said at least one non-conductive portion, the adjacent conductive portions each being in contact with one of the brushes of the pair of brushes when the collector-brush system is in the interrupted position.

[0013] The conductive portion is made of copper and the non-conductive portion is made of plastic material.

[0014] The rotor extends around the stator, with the commutator mounted on a side surface of the rotor.

[0015] The stator extends around the rotor, the motor having a shaft on which the rotor is mounted, the commutator being mounted on said shaft.

[0016] The motor is a limited travel magnet motor.

[0017] The contactor comprises a stop piece assembled to the frame, the stop piece comprising an assembly element configured to cooperate with a complementary assembly element formed in the rotor.

[0018] The contactor has several pairs of brushes, each formed by two brushes.

[0019] Other features and advantages of the invention will become apparent in the description below with reference to the appended drawings, given as non-limiting examples: Figure 1 shows in perspective and in top view a contactor according to a first embodiment of the invention, the contactor being in a connected configuration; Figure 2 is a detailed view of a brush device of the contactor; Figure 3 shows in perspective and in top view the contactor in a disconnected configuration; Figure 4 shows schematically an electrical circuit of the contactor; Figure 5 is a perspective view of a contactor according to a second embodiment of the invention; and Figure 6 represents a contactor according to a third embodiment of the invention.

[0020] Figures 1 to 3 represent a contactor 1 according to one embodiment of the invention. An electrical circuit of the contactor 1 is shown, schematically, in Figure 4.

[0021] The contactor comprises an electric motor 2 and a collector-brush system 3.

[0022] The contactor also includes a frame (not shown in the figures).

[0023] The electric motor 2 constitutes the control part of the contactor.

[0024] The motor 2 comprises a stator 200 and a rotor 201. The stator 200 constitutes the fixed part of the motor 2 and the rotor 201 the rotating part. The rotor 201 is configured to rotate about an axis of rotation X. The stator 200 and the rotor 201 are coaxial.

[0025] In the exemplary embodiment of Figures 1 to 3, the rotor 201 extends around the stator 200. In a variant shown in Figure 6, the stator 200 can extend around the rotor 201.

[0026] The motor further comprises an interface part 203. The interface part 203 is configured to be fixed to the frame of the contactor 1. The interface part 203 is here fixed to one end 204 of the stator 200.

[0027] Motor 2, for example, is a permanent magnet motor with limited travel. The limited travel motor has a single winding. Supplying the winding with direct current, in the positive direction, allows the motor to rotate in a given direction of rotation. Supplying the winding with direct current, in the negative direction, allows the motor to rotate in the opposite direction.

[0028] Using a magnet motor is also advantageous in that the motor is inherently balanced. The motor is most balanced when the magnets are identically offset from each other.

[0029] In one variant, the motor comprises two windings in phase opposition. Supplying a first of said windings with a positive direct current allows, for example, rotation in a first direction, and supplying a second of said windings with a positive direct current allows rotation of the motor in a second direction opposite to the first direction.

[0030] In one embodiment, one or both motor windings are connected in series with an anti-reverse polarity diode. This prevents connection or control order errors.

[0031] The brush-collector system 3 constitutes the electrical contact part of the contactor.

[0032] The collector-brush system 3 comprises a collector 300 and a brush device 301.

[0033] The collector 300 has a cylindrical shape. In particular, the collector 300 here has an annular shape.

[0034] The collector 300 comprises at least one conductive portion 302 and at least one non-conductive portion 303.

[0035] In the example illustrated in Figures 1 to 3, the collector comprises several conductive portions 302 and non-conductive portions 303. The collector 300 comprises an alternation of conductive portions 302 and non-conductive portions 303. In other words, any conductive portion 302 is circumferentially adjacent to a non-conductive portion 303. The conductive portions 302 are hatched in Figures 1 to 3 and 6.

[0036] In the illustrated example and as clearly visible in FIG. 2, the conductive portions 302 are inserted into an insulating support. The parts of the insulating support extending between the conductive portions 302 form the non-conductive portions 303. Alternatively, the conductive portions 302 and the non-conductive portions 303 may be completely separate.

[0037] The conductive portions 302 and the non-conductive portions 303 form the periphery of the collector 300. In other words, faces of the conductive portions 302 and the non-conductive portions 303 form a lateral surface of the collector 300.

[0038] The conductive portions 302 and the non-conductive portions 303 here have the same shape. The conductive portions 302 and the non-conductive portions 303 are here blades. The conductive portions 302 and the non-conductive portions 303 have a rectangular shape. The conductive portions 302 are here narrower than the non-conductive portions 303.

[0039] The use of identical conductive and non-conductive portions, for example blades, allows balancing of the collector.

[0040] In other exemplary embodiments, the conductive portions 302 and the non-conductive portions 303 may have a different shape and / or dimensions. For example, the conductive portions 302 and the non-conductive portions 303 may be rectangular blades of the same width.

[0041] The conductive portions 302 may be made of any electrically conductive material, for example metal such as copper.

[0042] The non-conductive portions 303 can be made of any insulating material, for example plastic material.

[0043] The non-conductive portions 303 may also be formed by an empty space separating conductive portions. The air in the empty space provides electrical insulation between the conductive portions 302. In one exemplary embodiment of the invention, the empty space is formed by splitting a conductive blade in two, as seen in Figure 5 and detailed further in connection with this figure. In another exemplary embodiment not shown, the empty space may extend in place of the non-conductive portions 303 materially shown in the embodiment of Figures 1 to 3.

[0044] The collector 300 is assembled to the rotor 201 of the electric motor 2. The collector 300 is rotatable about the axis of rotation X. The collector 300 is actuated by the motor 2. Rotation of the rotor 201 in one direction causes rotation of the collector 300 in the same direction.

[0045] In the example shown, the rotor 201 constitutes an outer armature and the stator 200 constitutes an inner armature of the motor 2. The collector 300 is mounted on a lateral surface of the rotor 201. In other words, the collector 300 is mounted around the motor 2. This makes it possible to limit the height of the contactor 1, i.e. say the dimension of contactor 1 according to the direction of the axis of rotation X. The contactor thus obtained is compact.

[0046] In the embodiment in which the stator 200 of the motor extends around the rotor 201, the commutator 300 may be assembled to the rotor 201 otherwise. The commutator 300 may be mounted on an output shaft 205 of the motor 2, as illustrated in FIG. 6.

[0047] The brush device 301 comprises at least one pair of brushes 304 (clearly visible in FIG. 2).

[0048] Each pair of brushes 304 is connected to an input and an output of the contactor 1.

[0049] Each brush 304 comprises a contact face 305. The contact face 305 of the brush 304 is configured to rub against the collector 300. The pair of brushes 304 constitutes a contact of the contactor 1. The contactor 1 may comprise several pairs of brushes 304 making it possible to switch several lines with the same collector 300. Eight pairs of brushes (i.e. sixteen brushes) are shown in Figures 1 and 2, but of course the brush device may comprise a different number of brushes. The number of pairs of brushes depends on the desired number of contacts.

[0050] 304 brushes are made from carbon, for example.

[0051] The brush device 301 also comprises at least one brush holder 306 and a support 307. The brush device 301 here comprises eight brush holders 306.

[0052] Each brush holder 306 can accommodate a pair of brushes 304. The brush holder 306 comprises two cages 308. Each cage 308 is configured to receive one of the brushes 304.

[0053] The brush holder 306 is mounted on the support 307. The support 307 has an annular shape. The support 307 extends around the commutator 300. The support 307 is orthogonal to the axis of rotation X.

[0054] The support 307 comprises an electrically conductive plate, for example made of steel.

[0055] In the example shown, the cages 308 of the brush holder are arranged on either side of the support 307. Each pair of brushes 304 is one above the other. the other, in the axial direction relative to the collector 300. The pairs of brushes 304 are arranged around the collector 300.

[0056] Alternatively, the cages 308 may be arranged circumferentially next to each other. Each pair of brushes 304 is next to each other around the collector 300. For example, the cages 308 may be arranged on the same side of the support 307.

[0057] Each cage 308 receives at least one spring (not shown). The spring is configured to push the brush 304 against the collector 300. The spring continuously exerts a force on the brush tending to push the brush against the collector. Good contact of the brushes with the collector is thus ensured.

[0058] Thanks to the springs, the 304 brushes are said to be preloaded. The 304 brushes remain in contact even in the presence of shocks, vibrations, or accelerations. Since the collector-brush system is used in applications operating in prolonged rotation at relatively high speeds (of the order of 50 m / s), the friction torque of the brushes on the collector will remain relatively low.

[0059] The brush device 301 is configured to be attached to the frame (not shown) of the contactor 1.

[0060] The contactor 1 further comprises at least one stop piece 4. The stop piece 4 is configured to limit the rotation of the motor 2.

[0061] The stop piece 4 is assembled on the one hand to the frame (not shown) and on the other hand to the rotor 201.

[0062] The stop piece 4 comprises an assembly element 401 configured to cooperate with a complementary assembly element 202 formed in the rotor 201.

[0063] In the illustrated example, the assembly element 401 is a finger. The complementary assembly element 202 is a notch. The notch 202 is configured to receive the finger 401. The finger 401 is configured to move in the notch. 202.

[0064] According to a variant, the assembly element may be a notch and the complementary assembly element a finger.

[0065] The stop piece 4 here comprises a plate 402 extending orthogonally the assembly element 401. The plate 402 comprises a hole 400. The hole 400 has an oblong shape. The plate 402 allows the fixing of the stop piece 4 to the frame. The stop piece is for example fixed to the frame by means of a screw inserted in the hole 400. The oblong shape of the hole 400 makes it possible to adjust the position of the stop piece 4 relative to the frame. The contactor 1 here comprises a stop piece 4. Alternatively, the contactor 1 can of course comprise several stop pieces 4.

[0066] The rotor 201 may comprise several notches 202. One or more of the notches 202 may be configured to cooperate with one or more of the stop pieces 4. In one exemplary embodiment, the number of stop pieces 4 and notch 202 may be the same. Each stop piece 4 is then configured to cooperate with one of the notches 202. In another exemplary embodiment, the number of notches 202 may be greater than the number of stop pieces 4. The stop piece(s) are each configured to cooperate with one of the notches 202. The additional notches 202, i.e. in addition to the number of stop pieces 4, make it possible to minimize the unbalance on the rotor. If the unbalance is sufficiently reduced, the action of shocks, vibrations, or accelerations on the rotor and the collector will create a negligible resulting torque which can be largely compensated by the restraining torque of the motor.The collector will not move even in the presence of shocks, vibrations, or accelerations.

[0067] The notches 202 can be made symmetrically with respect to the axis of rotation X. The rotor 201 can for example comprise three notches 202 each placed at 120° with respect to each other.

[0068] In the example of Figures 1 and 2, the rotor 201 comprises three notches 202 and the contactor 1 comprises a stop piece 4.

[0069] When the electric motor is of the permanent magnet type with limited travel, the stop piece(s) 4 are positioned so as to limit the rotation of the limited travel motor over an operational range of the contactor.

[0070] Figure 5 shows another embodiment of the contactor 1 according to the invention. In this example, the collector comprises whole blades 302 and split blades 309. The whole blades form the conductive portions 302. The split blades 309 comprise two parts 310. The two parts 310 are for example made of the same material as the conductive portions 302. In other words, the parts 310 are individually conductive portions.

[0071] Each split blade 309 further comprises an empty space 311 between the two portions 310. The empty space 311 constitutes an electrical insulator. In other words, the empty space 311 constitutes a non-conductive portion 303.

[0072] In another embodiment, the collector may comprise several conductive portions separated from each other by an empty space. The adjacent conductive portions may have different dimensions. The adjacent conductive portions are, for example, blades of different widths. The brushes may be arranged circumferentially around the collector.

[0073] The operation of the contactor is described below. The description is given for a single contact and therefore a single pair of brushes 304, but of course applies to a greater number of contacts.

[0074] The collector-brush system 3 is movable between a conduction position and an interruption position. In the conduction position, the collector 300 electrically connects the pair of brushes 304. The contact is thus closed. In the interruption position, the collector 300 electrically isolates the pair of brushes 304. The contact is thus open.

[0075] The collector-brush system 3 passes from the conduction position to the interruption position, and vice versa, by rotation of the collector 300 around the axis of rotation X under the action of the electric motor 2. The collector-brush system 3 can pass from the conduction position to the interruption position by rotation of the collector 300 in a first direction of rotation, and from the interruption position to the conduction position, by rotation of the collector 300 in a second direction of rotation opposite to said first direction of rotation.

[0076] When the collector 300 comprises several pairs of brushes 304, the collector-brush system 3 has several conduction positions and interruption positions. More precisely, the collector-brush system 3 has at least one conduction position and at least one interruption position associated with each pair of brushes 304.

[0077] In the conduction position, the pair of brushes 304 rubs against a conductive portion 302, as seen in Figures 1 and 2.

[0078] The interrupted position depends on the construction of the collector 300. In the example illustrated in Figures 1 to 3, the collector is in the interrupted position when a non-conductive portion 303 is opposite the pair of brushes 304. In other words, when a non-conductive portion 303 is in contact with the pair of brushes 304, the collector-brush system 3 is in the interrupted position. The collector in the interrupted position is shown in Figure 3.

[0079] In an exemplary embodiment, the collector-brush system is in the interrupted position when the brushes of the pair are each in contact with one of the conductive portions 302, the conductive portions 302 being insulated from each other. The conductive portions 302 may be insulated from each other by the presence of an insulating material or an empty space.

[0080] According to a variant, the collector-brush system is in the interrupted position when a conductive portion is in contact with one brush of the pair and a non-conductive portion is in contact with the other brush of the pair.

[0081] In the embodiment of Figure 5, the collector-brush system is in the conduction position when the two brushes 304 of the pair are in contact with an entire blade 302. The collector-brush system is in the interruption position when each brush 304 is in contact with a portion 310 of the split blade 309.

[0082] In the embodiment where the adjacent conductive portions have different widths separated from each other by an empty space, the collector-brush system is in the conduction position when the two brushes of the pair are in contact with the same conductive portion. The collector-brush system is in the interruption position when each brush of the pair is in contact with a different conductive portion.

[0083] The contactor 1 is configured to take a connected configuration and a disconnected configuration. In the connected configuration, the collector-brush system 3 is in the conduction position. The contact formed by the pair of brushes 304 and the collector 300 is thus in the closed state. In the disconnected configuration, the collector-brush system 3 is in the interrupted position. The contact formed by the pair of brushes 304 and the collector 300 is thus in the open state.

[0084] The contactor 1 switches from the connected configuration to the disconnected configuration, and vice versa, by rotation of the collector 300 around the axis of rotation X under the action of the electric motor.

[0085] The electric motor 2 constitutes the control part of the contactor 1. The winding(s) constitute the control circuit of the contactor 1. The power supply to the electric motor makes it possible to rotate the commutator in order to create an open or closed contact between the brushes 304.

[0086] When the contactor comprises at least one stop piece 4, the stop piece 4 can be positioned so as to limit the rotation of the motor 2 and therefore of the collector-brush system 3 between the conduction and interruption positions.

[0087] When the motor 2 is a magnet motor, it can be configured to obtain a holding torque of the magnets at the positions of the stop piece(s) 4. This allows it to be maintained in the conduction or interruption position even when the motor 2 is not electrically powered.

[0088] The contactor according to the invention is particularly suitable for use in harsh vibration environments, in particular thanks to its balancing. The contactor also requires low power to open or close the contact(s).

Claims

CLAIMS 1. Contactor comprising an electric motor (2) and a collector-brush system (3), the motor (2) being configured to be fixed to a frame and comprising a coaxial stator (200) and rotor (201), the rotor (201) being configured to be movable in rotation around an axis of rotation (X), the collector-brush system (3) comprising: a collector (300) assembled to the rotor (201) of the electric motor (2), the collector (300) having a cylindrical shape and comprising at least one conductive portion (302) and at least one non-conductive portion (303); and a pair of brushes formed by two brushes (304), said brushes (304) being configured to be fixed to the frame and each having a contact face (305) configured to rub against the collector (300), said contactor (1) being characterized in that a lateral surface of the collector (300) comprises said at least one conductive portion (302) and said at least one non-conductive portion (303) of the collector (300),the collector (300) being rotatable about the axis of rotation (X), the collector-brush system (3) being configured to move between a conduction position in which the collector (300) electrically connects the pair of brushes (304), and an interruption position in which the collector (300) electrically isolates the pair of brushes (304), at least one conductive portion (302) being in contact with the brushes (304) and no non-conductive portion (303) extending between the two brushes (304) when the collector-brush system (3) is in the conduction position, a non-conductive portion (303) being in contact with at least one of the brushes (304) of the pair of brushes or a non-conductive portion (303) extending between the two brushes (304) of the pair of brushes when the collector-brush system (3) is in the interruption position, the collector-brush system (3) passing from the conduction position to the interruption position, and vice versa,by rotation of the collector (300) around the axis of rotation (X) under the action of the electric motor (2)., 2. Contactor according to claim 1, in which the same conductive portion (302) is in contact with the two brushes (304) of the pair of brushes when the collector-brush system (3) is in the conduction position, and at least one non-conductive portion (303) is in contact with at least one brush (304) of the pair of brushes when the collector-brush system (3) is in the interruption position.

3. Contactor according to claim 1, in which the collector (300) comprises at least two conductive portions (302, 310), an empty space (311) separating two adjacent conductive portions (302, 310), said empty space (311) forming said at least one non-conductive portion (303), the adjacent conductive portions (302, 310) each being in contact with one of the brushes (304) of the pair of brushes when the collector-brush system (3) is in the interrupted position.

4. Contactor according to claim 1 or claim 2, wherein said at least one conductive portion (302) is made of copper and said at least one non-conductive portion (303) is made of plastic material.

5. Contactor according to one of claims 1 to 4, in which the rotor (201) extends around the stator (200), the collector (300) being mounted on a lateral surface of the rotor (201).

6. Contactor according to one of claims 1 to 4, in which the stator (200) extends around the rotor (201), the motor (2) comprising a shaft (205) on which the rotor (201) is mounted, the collector (300) being mounted on said shaft (205).

7. Contactor according to one of claims 1 to 6, in which the motor (2) is a motor with limited travel magnets.

8. Contactor according to one of claims 1 to 7, comprising a stop piece (4) configured to be assembled to the frame, the stop piece (4) comprising an assembly element (401) configured to cooperate with a complementary assembly element (202) formed in the rotor (201).

9. Contactor according to one of claims 1 to 8, comprising several pairs of brushes each formed by two brushes (304).

Images