PTAB

IPR2018-00441

American Honda Motor Co., Inc. v. Intellectual Ventures II LLC

Title: Motor with Thermoplastic Encapsulated Stator
Brief Description: The ’944 patent describes a design for an electric motor where the stator components, including the core and windings, are substantially encapsulated using a thermoplastic material. This encapsulation provides a monolithic body intended to facilitate heat dissipation, dampen vibration, and rigidly secure the motor’s components.

Prior Art Relied Upon: Nakahara (Japanese Patent Publication No. 10-271721).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Nakahara teaches every element of claim 3. Nakahara discloses an electric motor comprising a pole assembly (stator core 12 with windings 13), a shaft (22) spaced apart from the pole assembly, and a thermoplastic resin (stator housing 11) that is secured to the shaft and substantially encapsulates the pole assembly. The thermoplastic housing allegedly joins the shaft to the pole assembly, filling the space between them to rigidly fix the components together, thus anticipating the claim.

Prior Art Relied Upon: Itaya (Japanese Patent Publication No. 59-000592) and Konishi (Japanese Patent Publication No. 10-238491).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner asserted that Itaya, which discloses a motor for an electric pump, teaches all limitations of claim 3 except for explicitly identifying the encapsulating "resin" (frame 11) as a "thermoplastic." Itaya shows a pole assembly (core 2, windings 3), a spaced-apart shaft (5), and a resin frame that encapsulates the assembly and fixes it to the shaft. Konishi was argued to supply the missing element by expressly teaching the use of injection-molded thermoplastic to encapsulate and fix stator components in an electronic pump motor for high strength and integrity.
- Motivation to Combine: A POSITA would combine Itaya's motor design with Konishi's encapsulation method because both references address motors in pump devices and seek to achieve robust, sealed stators. Applying Konishi's thermoplastic encapsulation to Itaya’s motor would be a predictable way to improve strength and create a watertight seal, a stated goal in Itaya.
- Expectation of Success: Success would be expected because the combination merely applies a known material (thermoplastic) for its known purpose (encapsulation for strength and sealing) in a highly analogous device.

Prior Art Relied Upon: Bramm (Patent 4,944,748) and Watterson (Patent 6,227,797).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Bramm, which discloses a motor for an artificial heart pump, teaches the core elements of claims 9, 10, and 11. Bramm shows a motor with a core (pole pieces 430, 432), magnets (74, 76) spaced from the core, and conductors (coils 110, 112, 438, 440), all encapsulated by a plastic housing (44). However, Bramm does not specify the plastic is a "thermoplastic." Watterson, which also discloses an artificial heart pump motor, was argued to remedy this by teaching the use of a specific thermoplastic (Lexan polycarbonate) to encapsulate stator components, thereby increasing mechanical stiffness and allowing precise component positioning.
- Motivation to Combine: A POSITA would be motivated to use Watterson's thermoplastic in Bramm's motor because both references are in the same specific field of artificial heart pumps. The stated benefits in Watterson of increased stiffness and precise component control would be directly and predictably applicable to the similar motor structure in Bramm.
- Expectation of Success: A POSITA would have a high expectation of success in making the substitution, as it involves using a well-known material for its intended purpose in a nearly identical application to achieve predictable improvements.

Prior Art Relied Upon: Trago (Patent 5,806,169).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner contended that Trago, which discloses an injection-molded motor assembly, anticipates all limitations of claims 10 and 11. Trago teaches a motor with conductors (windings 73), magnets (85) forming poles, and a "thermoplastically processible resin" (molded plastic material 98) that encapsulates the conductors and magnets. Petitioner argued this material also locates and precisely positions the conductors relative to the magnets, fulfilling all claim elements. It was noted that the ’944 patent’s attempt to distinguish Trago as a "step motor" is irrelevant because the challenged claims are not limited to a specific motor type like a high-speed spindle motor.

"filling in the space...such that the [components] are rigidly fixed together": Petitioner argued this phrase, central to claims 3 and 9, does not require the thermoplastic to fill the entirety of the space between components. Based on the ’944 patent’s specification (e.g., Fig. 14 showing bearings and empty space) and prosecution history, Petitioner asserted the term should be construed to mean filling a portion of the space sufficient to rigidly fix the components to each other. This construction is critical to mapping prior art that shows partial filling.

Petitioner requested that the Board institute an inter partes review and cancel claims 3, 9, 10, and 11 of the ’944 patent as unpatentable.