(1) Field of the Invention
The invention relates to an electric motor for a fluid pump, in particular an oil pump. The invention furthermore relates to a modular motor family and a method for producing an electric motor for a fluid pump.
(2) Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
According to experience, electric motors are used to drive various vehicles and machines, including oil pumps. The functional principle of an electric motor is based on the conversion of electrical energy into mechanical energy. In doing so, the force exerted by a magnetic field on the current-carrying conductor of the electric motor is converted into movement and rotation.
As is known, brushless direct-current motors, so-called BLDC motors, are used for driving pumps for oil production. Such an electric motor is, for example, known from U.S. Pat. No. 6,788,015. The motor comprises a fixed stator, which contains coil windings, which may be controlled by an electronic circuit at different times. A rotatably mounted rotor is located in the stator. Rotors are generally realized with a permanent magnet. If an electric current flows in the stator windings, a magnetic field forms in the stator. This magnetic field also penetrates the permanent magnets of the rotor. Acting on the rotor is a torque, which sets the rotor into rotation. So that the rotation of the rotor does not stop, the current flow in the stator windings must be switched early enough so that the generated magnetic field continues to rotate and a torque continues to act on the rotor.
EP 1 523 087 A1 relates to an electric motor with a substantially closed motor housing which accommodates a rotor and a stator, with a motor flange which forms a section of the motor housing, with an electronic system for controlling the electric motor, and with a substantially closed electronic housing which accommodates the electronic system and is connected to the motor housing. In this case, the electronic housing and the motor housing form two separate housing units.
As described in EP 1 523 087 A1, the electronic system for controlling the motor is integrated into the electronic housing. By regulating the currents in the stators, a magnetic field of variable direction and size can be generated. The electronic system may include any type of electronic control system with which the electric motor can be controlled. The electronic control system typically depends on the motor. Direct-current motors need an electronic control system for commutating the electric supply currents to the individual stator windings. Alternating-current motors require an electronic system for regulating their rotational speed, for example.
In addition to the electronic control system, an electronic positioning system may also be introduced into the electronic housing. There are various ways of measuring the position of the rotor. For example, several Hall sensors may be mounted at the rotor end. The magnetic field changes generated by the rotation, and thus the position of the rotor, can be detected by the Hall sensor. By means of position sensors, a differentiated and efficient control of the torque of the motor is possible even at high speeds.
As a result of the great variety and the many possible uses of electric motors, work was mostly carried out in a customer-oriented manner in the past. This means that the previous motors were exclusively developed according to the wishes of the customer and according to the specific purpose of the motor. A flexible use of an electric motor for various areas of application is not provided thereby. The finished motors were neither suitable for new customer requests nor adaptable for use by others. As a consequence, customer-specific motors for a different purpose have to be produced de novo at high costs. This also results in additional high installation and repair costs.
The present invention is therefore based on the task of developing cost-effectively producible electric motors that are suitable for various applications with the smallest possible modification. Important in this respect is a modular structure of the electric motor that can be redesigned for a different purpose without much modification effort. It is furthermore the task of the invention to provide a modular motor family with comprehensive electric motors as well as a production method for an electric motor.
The present invention is based on the idea of providing an electric motor for a fluid pump, in particular an oil pump, the electric motor comprising a housing in which a stator, a rotor, and a tapping plate are arranged, wherein the tapping plate comprises connecting contacts for an electrical connection to windings of the stator and connecting elements for connecting to an electronic control system and/or electronic positioning system. The tapping plate is formed or overmolded by a plastic material, and the stator is encased by an overmolding that forms a bearing seat for the rotor.
The invention is furthermore based on the idea of providing a modular motor family for forming different, in particular differently powerful, fluid pumps, comprising several brushless electric motors, wherein each electric motor is made up of a housing in which a stator and a rotor and/or a tapping plate are arranged, wherein the tapping plate includes connecting contacts for an electrical connection to windings of the stator and connecting elements for connecting to an electronic control system and/or electronic positioning system, and the stator is encased by an overmolding which forms a bearing seat for the rotor, and wherein the individual electric motors differ from each other by different motor diameters and/or motor lengths and/or configuration variants.
A modular structure of an electric motor and the development of a motor family brings a multitude of advantages. As a result of the modularized and thus standardized motor structure, development and business process costs can be kept low. Structurally identical series of motor families are inexpensive in their production and ensure easier installation processes. With respect to the maintenance of motors, a modular structure can guarantee cost-effective repair. In particular, an easy replacement of faulty or damaged components can be achieved thereby.
A standardized structure moreover offers great flexibility in the product range as well as a diverse variety of products. If different modules of a motor are available, the motor can be adapted to new conditions quickly and easily. The standardized motor modules can simply be remounted, removed, changed, or grouped otherwise. Several customer-specific purposes can thus be realized using a modular motor structure.
In a preferred embodiment, the motor can have a smallest possible installation space. In this case, the motor comprises, for example, a housing in which a stator, a rotor, and a tapping plate are arranged. The tapping plate is made up of connecting contacts for electrical connection to the windings of the stator. The connecting contacts can, for example, be designed as flat plugs. With respect to the motor family of modularized motors, at least two different stator lengths and/or motor diameters are conceivable. With scalable motor lengths, a variety of applications can be covered.
The stator is preferably encased by an overmolding which forms a bearing seat for the rotor. The overmolding serves to seal the motor. The motor can thus be used in splash-water areas and a separation between wet and dry chambers can thus be ensured. The tapping plate is advantageously formed and/or overmolded by a plastic material, in particular a thermosetting material. Above all, the sensitive electronic system is ideally overmolded for the purposes of oil-tightness and is thus protected from external damage. It is conceivable that the tapping plate and the stator comprise the same, or a uniform, in particular a common, overmolding.
The tapping plate can advantageously be formed by a lead frame. Lead frames are particularly suitable in areas in which electric currents must be distributed in tight spaces. The lead frame itself can be encased in plastic. This again provides sealing and protection for the electronic system. It is conceivable for the surface of the lead frame also to be galvanically refined. The use of a lead frame is ideally space saving.
It is in particular advantageous in this connection if the tapping plate comprises at least two connecting elements. The connecting elements serve the electrical connection of the motor to an electronic system. The connecting elements of the tapping plate can in this case be aligned orthogonally or alternatively parallel to the tapping plate. The different alignment of the connecting elements allows for a varied alignment of the motor within the assembly and in relation to the fluid pump. In this embodiment, the stator overmolding preferably contains a plug housing for safely accommodating the connecting elements.
The tapping plate is ideally secured as by welding or hot-pressing to a plastic material or ceramic material. The invention is not limited to a plastic material or ceramic material. Other insulating materials, such as glass, are also conceivable. In an alternative embodiment, the tapping plate is glued to and/or bonded to and/or cast with and/or overmolded with a plastic material.
In an advantageous embodiment, the housing of the motor comprises an accommodation chamber for an electronic control system and/or electronic positioning system. The accommodation chamber can in this case be arranged axially or radially in relation to the motor axis. The accommodation chamber can be separated from the stator by a separating wall. A separation of the electronic system from the stator allows for simplified repair in the case of damage or malfunctioning since the electronic system is quickly accessible within the accommodation chamber.
The connecting elements advantageously extend through the separating wall. The separating wall can, for example, form a side wall or an axial end wall or an intermediate wall of the housing.
In a preferred embodiment, a circuit board for the electronic control system and/or electronic positioning system is mounted in the accommodation chamber. The circuit board can be connected or is connected electrically to the connecting elements. The circuit board and thus also the electronic system is ideally overmolded with a plastic material or ceramic material. This protects the sensitive electronic system from external damage and ensures oil tightness of the electrical connectors.
In an advantageous embodiment of the invention, the accommodation chamber of the electronic system is sealed using a cover. This cover can, for example, be provided with a rubber seal. The rubber seal can be an O-ring or be designed as a flat seal. Alternatively, the seal can be designed as liquid silicone-rubber injection molding or as injection-molded liquid silicone. The cover can be connected in a sealed manner to the accommodation chamber or to an accommodation pocket. This connection can be effected by a substance-to-substance bond or by a force fit, for example by gluing, welding, or screwing. A plug housing for the connecting elements of the tapping plate can integrally be molded onto the cover.
The overmolding ideally comprises a plastic material, in particular a thermosetting material, or alternatively a thermoplastic material. The plastic material of the housing can be designed to be integral or in one piece with the plastic material for overmolding the tapping plate and/or the circuit board. A thermosetting material has a high stiffness in order to protect the motor or the tapping plate with the electronic system from external deformation or damage. The thermosetting material moreover has a high thermal and chemical resistance.
A related aspect of the invention relates to a modular motor family for forming differently powerful fluid pumps with several comprehensive brushless electric motors. As a common feature, all electric motors have a housing in which a stator and a rotor and/or a tapping plate are arranged as well as an overmolding of the stator. The tapping plate comprises connecting contacts for the electrical connection to windings of the stator, as well as connecting elements for connecting to an electronic control system and/or electronic positioning system. The individual electric motors however differ by the following modular configuration features:
In one configuration variant, the housing can advantageously form an end-face accommodation chamber for the electronic control system and/or electronic positioning system at a longitudinal axial end. In this case, the tapping plate can comprise at least two connecting elements, which are aligned orthogonally to an annular face of the tapping plate and project into the end-face accommodation chamber.
In another configuration variant, the housing can alternatively form a circumferential accommodation chamber for the electronic control system and/or electronic positioning system on a circumference. The tapping plate can once again comprise at least two connecting elements, which are aligned parallel to an annular face of the tapping plate and project into the circumferential accommodation chamber.
The motor family can generally comprise several electric motors of different motor diameters and/or motor lengths, wherein the electric motors are equipped with or without position sensor and/or with or without electronic control system and are constructed in accordance with the structure of an electric motor described above. The possible configuration with different electronic system designs and/or motor lengths expands the usability of the motors for the most varied purposes, in particular in the area of fluid pumps and oil pumps. A great product variety is ensured thereby.
Another related aspect of the invention relates to a method for producing an electric motor with predetermined specifications for a fluid pump, in particular an oil pump. The method is suitable in particular for the production of an electric motor for a motor family with the previously explained features, wherein several standard components can be combined with each other in order to satisfy a previously determined specification. The standard components comprise one or more electric motors having different motor diameters and/or motor lengths, one or more different position sensors for integration into the electric motors, and/or one or more different electronic control systems for controlling the electric motors, wherein the electronic control systems can be arranged in an accommodation chamber of a housing of the electric motor.
The present invention is explained in more detail below with reference to the accompanying schematic drawings. These show:
In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.
The tapping plate 20 can be mounted on an end face of the stator 10. The tapping plate 20 is designed as annular with an inner opening for the rotor 30. On the underside of the tapping plate 20, several connecting contacts 21 are mounted externally. These connecting contacts are, for example, designed as flat plugs. The connecting contacts 21 connect the tapping plate 20 to the stator windings 15, which are invisibly arranged in the stator core 12. The connecting contacts 21 are orthogonal to the tapping plate 20. The tapping plate 20 comprises three connecting elements 23 for the electric equipment of the motor. The connecting elements 23 are shown as elongated plugs and are aligned orthogonally to the tapping plate 20. Alternatively, the connecting elements 23 can also be arranged parallelly to the tapping plate 20. The tapping plate 20 has several circular recesses 22. The recesses 22 serve to connect additional electronic systems and additional connection contacts 24.
The electric motor comprises a rotor 30. The rotor shaft 31, on which a ball bearing 32 is mounted, runs in the center of the rotor 30. The rotor 30 is rotatably accommodated in the stator core 12.
For example, round, angular, or polygonal shapes for the accommodation chamber 43 are also conceivable. The size of the accommodation chamber 43 is ideally guided by the electronic system used. This means that the accommodation chamber 43 can also project beyond the housing. The round bearing seat 41 of the rotor 30 projects into the accommodation chamber 43. On the left side, the connecting elements 23 project from the accommodation chamber 43. For sealing, the accommodation chamber 43 can be closed by a substance-to-substance bond or by a force fit using a cover 46 (See
The cover 46 has the same cuboidal shape with a rounded side that fits onto the accommodation chamber 43 for the electronic system. The cover 46 can be connected by a substance-to-substance bond to the accommodation chamber 43, e.g., by gluing, welding, or soldering. A mounting by force fit by means of a screw connection is also conceivable. The cover 46 is ideally connected in a sealed manner to the accommodation chamber 43 so that the electronic system can be accommodated in the accommodation chamber 43 in a protected manner. For this purpose, the cover 46 can be provided with a rubber seal not shown. This rubber seal can, for example, be an O-ring or a flat seal. A plug housing 42 is integrally molded onto the cover 46. The plug housing 42 is cuboidal with rounded edges and stands orthogonally on the cover 46. The plug housing 42 can alternatively also be mounted on the cover 46 by a substance-to-substance bond. The plug housing 42 protects the three connecting elements 23, which project from the tapping plate 20 into the accommodation chamber 43 of the electronic system and also partially from the accommodation chamber 43.
The described modular structure of the electric motors with variable stator length and variable electronic control and positioning system allows for flexible and versatile use of the motors in the field of fluid pumps. In order to realize different possible electronic systems, the housing variations described in
Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described.
10 Stator
11 Stator lamination stack
11
a Housing base
11
b Carrier component
12 Stator core
13 Stator tooth
14 Stator slot
15 Stator winding
16 Insulating ring
17 Screwing device
18 Threaded connection
20 Tapping plate
20
a Base body
21 Connecting contact
22 Recess
23 Connecting element
24 Connection contact
25 Punch-out
26 Switching element
28 Plug contact
29 Circuit board
30 Rotor
31 Rotor shaft
32 Ball bearing
40 Housing
41 Bearing seat
42 Plug housing
43 Accommodation chamber
45 Covering
46 Cover
50 Opening
Number | Date | Country | Kind |
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102016101963.1 | Feb 2016 | DE | national |
The present patent application is a continuation of International Application No. PCT/DE2017/200012, filed Jan. 30, 2017, which is based on, and claims priority from, German Application No. DE 102016101963.1, filed Feb. 4, 2016, both of which are incorporated herein by reference in their entireties.
Number | Date | Country | |
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Parent | PCT/DE2017/200012 | Jan 2017 | US |
Child | 16047667 | US |