Claims:We claim:
1. A resolver [rotor] integrated slip ring assembly, comprises of:
a) a resolver rotor (201) molded along with a plurality of slip rings (204), wherein the resolver rotor (201) is molded through an in-situ molding;
b) the resolver rotor (201) and the slip ring molding (204) is fitted onto the rotor assembly,
wherein the plurality of slip rings (204) are fitted onto a slip ring mould (211) of a claw pole machine to provide electrical connections to a rotor field;
c) a resolver stator (203) molded on to the slip ring cover (202); and
d) an electronic control unit (210) connected to the resolver terminals (209) through the in-situ molding.
2. The resolver rotor integrated slip ring assembly as claimed in claim 1, wherein said assembly provides plurality of options to execute the assembly by fitting the assembly at any position on the slip ring mould.

3. A method to integrate the resolver rotor onto the slip rings, comprising the steps of:
a) molding a resolver rotor along with a plurality of slip rings through an in-situ moulding;
b) fitting the resolver rotor and the slip ring molding onto the rotor assembly;
c) molding a resolver stator on to the slip ring cover;
e) connecting the resolver stator to an electronic control unit through the in-situ molding; and

d) obtaining the output from the resolver stator without distortion.
, Description:[001] PREAMBLE TO THE DESCRIPTION:
[002] The following specification particularly describes the invention and the manner in which it is to be performed:
[003] DESCRIPTION OF THE INVENTION:
[004] Technical field of the invention
[005] The present invention relates to a resolver (rotor position sensors). More particularly, the invention relates to a resolver rotor integrated slip ring assembly.
[006] Background of the invention
[007] Resolver is a rotary electrical transformer device used for sensing the angular position of the rotor. A resolver has a stator with six leads, connected to three different windings. One winding is used for providing excitation. The other two are used for providing angular feedback. The feedback winding's are 90 degrees apart physically instead of 120 degrees. Typically the resolver stator is fixed on to the brackets of the machine. A resolver has a rotor with multiple lobes based on the requirement of angular position accuracy. Typically the resolver rotor is fixed on to the shaft of the rotor. The construction and wiring diagram of resolver are shown in figures 1a and figure 1b.
[008] In the current systems, the resolver rotor is assembled on to the shaft of the machine's rotor either by slide fit and fastening method or by press fit method. The resolver stator is assembled on to the bracket with slide fit and fastened with a retainer plate. The overall length of the machine is large as fasteners are used for the fitting. Therefore more number of components are employed.
[009] The Rotor flux of the machine is the flux used for converting electromagnetic energy to mechanical energy and vice versa. There is also a leakage component of rotor flux in the existing assemblies, which flows through the shaft to the ends of the shaft, as shaft is a magnetically conductive material. The output waveform of the resolver is distorted due to the interference of leakage flux. The effect of machine rotors leakage flux on resolver output is shown in figure 2. It is evident from the waveform that the output of the resolver is distorted due to the interference of leakage flux.
[0010] Hence, looking at the problems in the prior art, there is a need for a resolver integrated slip ring assembly which eliminates the effect of leakage flux on the resolver output. The assembly must be very simple, which eliminates number of components. Also, the system must have simple manufacturing process.
[0011] Summary of the invention:
[0012] The present invention overcomes the drawbacks in the prior art and provides a resolver rotor integrated slip ring assembly and the method to assemble thereof. The present invention comprises a resolver rotor molded along with a plurality of slip rings, wherein the resolver rotor is molded through an in-situ molding. The resolver rotor and the slip ring molding are fitted onto the rotor assembly, wherein the plurality of slip rings is fitted onto a slip ring mold of a claw pole machine to provide electrical connections to a rotor field. A resolver stator is molded on to the slip ring cover and an electronic control unit is connected to the resolver stator through the in-situ molding.
[0013] In the preferred embodiment of the present invention, the resolver rotor integrated slip ring assembly as claimed in claim 1, wherein said assembly provides plurality of options to execute the assembly by fitting the assembly at any position on the slip ring mold.
[0014] In the preferred embodiment of the present invention, the method includes the step for assembling the resolver rotor integrated slip ring assembly. Firstly, a resolver rotor is molded along with a plurality of slip rings through an in-situ molding. The resolver rotor and the slip ring molding are fitted onto the rotor assembly. Further, a resolver stator is fitted on to the slip ring cover. Then, the resolver stator is connected to an electronic control unit through the in-situ molding and finally, the output from the resolver stator is obtained.

[0015] Brief description of the drawings:
[0016] The foregoing and other features of embodiments will become more apparent from the following detailed description of embodiments when read in conjunction with the accompanying drawings. In the drawings, like reference numerals refer to like elements.
[0017] Figure 1 (a) and Figure 1 (b) illustrates a general construction and wiring diagram of resolver (Prior Art), in accordance with an embodiment of the invention.
[0018] Figure 2 illustrates the waveforms of the output of the resolver rotor (Prior Art), in accordance with an embodiment of the invention.
[0019] Figure 3 illustrates a sectional view of a resolver rotor integrated slip ring assembly, in accordance with an embodiment of the invention.
[0020] Figure 4 illustrates the waveforms of the output of the resolver rotor integrated slip ring assembly, in accordance with an embodiment of the invention.
[0021] Figure 5 illustrates the process flow for assembling the resolver rotor integrated slip ring assembly, in accordance with an embodiment of the invention.
[0022] Detailed description of the invention:
[0023] Reference will now be made in detail to the description of the present subject matter, one or more examples of which are shown in figures. Each embodiment is provided to explain the subject matter and not a limitation. These embodiments are described in sufficient detail to enable a person skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, physical, and other changes may be made within the scope of the embodiments. The following detailed description is, therefore, not be taken as limiting the scope of the invention, but instead the invention is to be defined by the appended claims.
[0024] The present invention provides a resolver rotor integrated slip ring assembly and the method to assemble thereof. The present invention comprises a resolver rotor molded along with a plurality of slip rings, wherein the resolver rotor is molded through an in-situ molding. The resolver rotor and the slip ring molding is fitted onto the rotor assembly, wherein the plurality of slip rings are fitted onto a slip ring mold of a claw pole machine to provide electrical connections to a rotor field. A resolver stator is molded on to the slip ring cover and an electronic control unit is connected to the resolver stator through the in-situ molding.
[0025] Figure 1 illustrates a general construction and wiring diagram of resolver (Prior Art), in accordance with an embodiment of the invention. In prior art, a resolver has a rotor with multiple lobes based on the requirement of angular position accuracy. Typically the resolver rotor is fixed on to the shaft of the rotor as shown in figures. The resolver rotor is fitted with slide fit and fastened with a retainer plate increasing the size of the machine.
[0026] Figure 2 illustrates the waveforms of the output of the resolver rotor (Prior Art), in accordance with an embodiment of the invention.
[0027] Figure 3 illustrates a perspective view of a resolver rotor integrated slip ring assembly, in accordance with an embodiment of the invention. The present invention comprises a resolver rotor (201) molded along with a plurality of slip rings (204), wherein the resolver rotor (201) is molded through an in-situ molding. The resolver rotor (201) and the slip ring molding (204) are fitted onto the rotor assembly. The plurality of slip rings (204) are fitted onto a slip ring mold (211) of a claw pole machine to provide electrical connections to a rotor field. The resolver comprises of resolver terminals (209), wherein the resolver terminals (209) are connected to electronic control unit (ECU) (210). The brushes (207) connect the rotor to the electronic control unit (ECU) (210).
[0028] A resolver stator (203) is molded on to the slip ring cover (202) and an electronic control unit (210) is connected to the resolver terminals (209) through the in-situ molding.
[0029] In the preferred embodiment of the present invention, the position of the resolver may also be at the different locations as shown in figures 3 (a) and figures 3 (b). In the figure 3 (a) the resolver (201) is fixed onto the tip of the slip ring mold (211) along with the slip rings (204). Similarly in the figure 3 (b), the resolver (201) is fixed onto the shank of slip ring mold (211) along with the slip rings (204). This type of arrangement eliminates a leakage component of rotor flux which flows through the shaft to the ends of the shaft. Thus, the effect of electromagnetic interference of leakage flux on resolver output is minimized.
[0030] Figure 4 illustrates the waveforms of the output of the resolver rotor integrated slip ring assembly, in accordance with an embodiment of the invention. The waveform as shown in figure 4 indicates that the resolver rotor integrated slip ring assembly provides an undistorted output without leakage flux in resolver zone.
[0031] Figure 5 illustrates the process flow for assembling the resolver rotor integrated slip ring assembly, in accordance with an embodiment of the invention. First at step (401), a resolver rotor is molded along with a plurality of slip rings through an in-situ molding. At step (402), the resolver rotor and the slip ring molding are fitted onto the rotor assembly. Further at step (403), a resolver stator is fitted on to the slip ring cover. Then at step (404), the resolver stator is connected to an electronic control unit through the in-situ molding and finally at step (405), the output from the resolver stator is obtained without distortion due non-interference of the leakage flux in resolver rotor.
[0032] Hence, the present invention provides an assembly, which is simple in design and the process involved in assembling is also very simple. The present invention eliminates the need of fasteners, therefore reducing the overall length of the machine. Also, the effect of leakage flux on the present assembly is eliminated, thereby eliminating distortion in the output.
[0033] It is to be understood, however, that even though several characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.