Nidec Corp v. Intellectual Ventures II LLC

1. Case Identification

• Case #: IPR2018-00598
• Patent #: 7,067,952
• Filed: February 15, 2018
• Petitioner(s): Nidec Corporation and American Honda Motor Co., Inc.
• Patent Owner(s): Intellectual Ventures II LLC
• Challenged Claims: 1-6, 8-14

2. Patent Overview

• Title: Stator Assembly Made from a Molded Web of Core Segments and Motor Using Same
• Brief Description: The ’952 patent discloses a method for manufacturing electric motor stator assemblies from discrete arc segments. These segments are linked together in a linear strip by a flexible "phase change material" webbing, which facilitates the winding of coils onto the segments before the entire strip is formed into its final toroidal (annular) shape for use in a motor.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 10 and 14 over Calsonic

• Prior Art Relied Upon: Calsonic (Japanese Patent Application Publication No. 2000-184635).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Calsonic discloses every element of independent claims 10 and 14. Calsonic teaches a stator made from divided core blocks (discrete stator segments) held by a "divided core holding member." This holding member is made from a thermoplastic resin, such as polybutylene terephthalate (PBT), which Petitioner contended is a "phase change material." The holding member includes thin "deformable portions" that link the segments into a continuous strip, satisfying the "bridge" limitation. Petitioner asserted that Calsonic’s disclosure of the core blocks being clamped between a pair of these holding members (upper and lower) meets the limitation of a bridge formed by "interconnecting two mating sections." Finally, Calsonic teaches that these linked segments are arranged and secured in an annular form to create the final stator assembly.

Ground 2: Obviousness of Claims 1, 2, 4, 6, 8, 9, 12, and 13 over Calsonic in view of Matsushita

• Prior Art Relied Upon: Calsonic (Japanese Patent Application Publication No. 2000-184635) and Matsushita (Japanese Patent Application Publication No. H11-341717).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Calsonic teaches the core elements of independent claim 1, including a plurality of discrete stator segments partially encased in a phase change material and linked by a bridge into a continuous strip. However, Calsonic does not explicitly teach holding the final annular assembly with a "metal band." Matsushita was introduced to supply this missing element, as it discloses holding annularly arranged stator segments together with a retaining member, such as a metal flat plate or a heat-shrinkable metal ring, to form the final stator.
  • Motivation to Combine: A POSITA would combine Calsonic's flexible stator strip with Matsushita's method for securing the final assembly. Both references address the manufacture of segmented stators and are thus analogous art. Petitioner argued that Matsushita provides the express motivation of using a metal band to make the stator "rigidly held to be prevented from deforming." A POSITA would recognize this benefit and apply Matsushita’s well-known retaining technique to Calsonic’s design, especially since Calsonic suggests that the method for joining the ends of its strip is "not particularly limited," inviting known solutions.
  • Expectation of Success: The combination would involve applying a known solution (a metal band for rigidity) to a known problem (maintaining the structural integrity of a segmented stator), which would yield the predictable result of a more robust and reliable stator assembly.

Ground 3: Obviousness of Claims 10, 12, and 14 over DENSO in view of Calsonic

• Prior Art Relied Upon: DENSO (Japanese Patent Application Publication No. S62-138031) and Calsonic (Japanese Patent Application Publication No. 2000-184635).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner used DENSO as the primary reference, arguing it teaches a method of manufacturing an armature by arranging discrete magnetic pole cores (stator segments) on a continuous resin support member. This member has thin-walled portions that allow the linear strip to be bent into a ring shape for winding. While DENSO discloses a linking bridge, it does not explicitly show a bridge formed by "interconnecting two mating sections." Calsonic was introduced to teach this specific feature, as it discloses clamping stator segments between a pair of upper and lower holding members.
  • Motivation to Combine: A POSITA would combine these references to improve upon DENSO's design. A POSITA would see Calsonic's use of two mating sections to clamp the segments as a simple and effective way to secure the pole cores in DENSO's flexible resin strip. This modification would improve the stability of the segments during manufacturing and winding. The use of "resin" in both references as the insulating and linking material would make the integration of Calsonic's clamping structure into DENSO's system straightforward.
  • Expectation of Success: Applying Calsonic’s specific clamping mechanism to DENSO’s flexible stator strip was presented as a simple substitution of known mechanical elements to achieve the predictable benefits of improved stability and securement.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including that claim 11 is obvious over Calsonic and Dunfield (Patent 5,694,268) for teaching an overmolded thermoplastic, and that claims 3 and 5 are obvious over Calsonic, Matsushita, and the general knowledge of a POSITA regarding wire packing density and material thermal conductivity.

4. Key Claim Construction Positions

• "a phase change material": Petitioner proposed that under the broadest reasonable interpretation, this term means "a material that can be used in a liquid phase to envelop[] the stator, but which later changes to a solid phase." This construction is broad enough to encompass the thermoplastics (like PBT and PET) and thermoset resins disclosed in the prior art references.
• "the bridge is formed by interconnecting two mating sections formed from the phase change material": Petitioner argued this is a product-by-process limitation where patentability depends on the final product structure, not the method of its formation. Therefore, the limitation is met if the prior art discloses a final bridge structure that comprises two interconnected mating sections made of the material, regardless of the specific process used to join them. This was critical to mapping Calsonic, which shows a structure with two clamping members.

5. Key Technical Contentions (Beyond Claim Construction)

• Effective Filing Date: A central contention was that the ’952 patent is not entitled to the March 2, 2001 filing date of its parent (’207 patent) and should be accorded its actual filing date of March 5, 2003. Petitioner argued that the key claim limitations, such as the "bridge" and "flexible carrier" linking the segments, were newly introduced in the application for the ’952 patent and lack written description support in the parent ’207 patent. This argument was crucial for establishing that Calsonic, published in 2000, qualifies as prior art under 35 U.S.C. §102(b).

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-6 and 8-14 of the ’952 patent as unpatentable.