Abstract: An oil separation member has a partition member that partitions between a discharge chamber and a discharge passage. A circular ring portion is provided in the partition member in a manner extending toward the discharge passage. An introduction hole that communicates the discharge chamber and the discharge passage with each other is formed in the circular ring portion. The introduction hole extends in a tangential direction to the circular ring portion.

Abstract: A rear housing includes a first passage extending from an accommodation chamber towards a communication hole of a valve-forming plate. A cylinder block includes a connection portion to be connected to an external device, an outlet space opening towards the connection portion, and a second passage extending from the outlet space towards the communication hole of the valve-forming plate. A discharge passage includes a discharge chamber, the accommodation chamber, the first passage, the communication hole, the second passage, and the outlet space. The flow passage area of the communication hole is larger than at least one of the flow passage area of the first passage and the flow passage area of the second passage. The discharge passage can be designed with high flexibility.

Abstract: An oil separation member has a partition member that partitions between a discharge chamber and a discharge passage. A circular ring portion is provided in the partition member in a manner extending toward the discharge passage. An introduction hole that communicates the discharge chamber and the discharge passage with each other is formed in the circular ring portion. The introduction hole extends in a tangential direction to the circular ring portion.

Abstract: A rear housing includes a first passage extending from an accommodation chamber towards a communication hole of a valve-forming plate. A cylinder block includes a connection portion to be connected to an external device, an outlet space opening towards the connection portion, and a second passage extending from the outlet space towards the communication hole of the valve-forming plate. A discharge passage includes a discharge chamber, the accommodation chamber, the first passage, the communication hole, the second passage, and the outlet space. The flow passage area of the communication hole is larger than at least one of the flow passage area of the first passage and the flow passage area of the second passage. The discharge passage can be designed with high flexibility.

Abstract: A plurality of convex portions are located inside of a virtual circumferential surface. Each convex portion connects an adjacent pair of circumferential portions with each other. Each convex portion is an arcuate curve bulging radially outward. Each convex portion defines a minimum radius. A difference between a radius R and the minimum radius is a depth Dh. Dhr=Dh×25.5/R. A range of an angular width A in relation to circumferential portion and a range of the depth Dh are set by the following expression, (5.6×Dhr+11.3)°×6/p?A<35°×6/p and A<[360/p?2×arccos]°??(1) Therefore, decrease in torque is prevented. Torque pulsation is suppressed.

Abstract: A housing of an electric motor includes an inner circumferential surface, which includes recesses arranged along the circumferential direction. On an outer circumferential surface of a stator core of a stator are provided protrusions arranged along the circumferential direction. Fitting each protrusion to the corresponding recess fixes the stator core to the housing. A rotor is provided radially inward of the stator. In a state where each protrusion is fitted to the corresponding recess, a pair of side surfaces of each protrusion are retained by a pair of inner side surfaces of the corresponding recess in the circumferential direction of the housing. A gap is formed between an end face of each protrusion and an inner bottom surface of the corresponding recess facing the end face along the entire surface of the end face.

Abstract: A rotating electric machine including circumferential portions respectively corresponding to magnetic pole centers of permanent magnets and defined along the outer circumference of the rotor at a plurality of locations, with each circumferential portion extending along part of a virtual circumferential surface, which is coaxial with the rotor. The circumferential portions are spaced from one another in the circumferential direction. Convex portions connect adjacent pairs of the circumferential portions. Each convex portion is located radially inward from the circumferential surface, projects in a radially outward direction, and includes angled portions directed in the radially outward direction. The rotating electric machine suppresses decrease in the average value of the output torque and does not use reluctance torque to increase the average value of the output torque.

Abstract: A housing of an electric motor includes an inner circumferential surface, which includes recesses arranged along the circumferential direction. On an outer circumferential surface of a stator core of a stator are provided protrusions arranged along the circumferential direction. Fitting each protrusion to the corresponding recess fixes the stator core to the housing. A rotor is provided radially inward of the stator. In a state where each protrusion is fitted to the corresponding recess, a pair of side surfaces of each protrusion are retained by a pair of inner side surfaces of the corresponding recess in the circumferential direction of the housing. A gap is formed between an end face of each protrusion and an inner bottom surface of the corresponding recess facing the end face along the entire surface of the end face.

Abstract: An electric motor includes an annular housing and an annular stator core having the inner periphery the shape of which differs from a perfect circle. The stator core is supported by the housing in such a manner that the outer periphery of the stator core and the inner periphery of the housing are partially in contact with each other. The inner periphery of the stator core is deformed to become close to the shape of the perfect circle when the stator core is securely fitted in the housing by shrink fitting.

Abstract: A plurality of convex portions are located inside of a virtual circumferential surface. Each convex portion connects an adjacent pair of circumferential portions with each other. Each convex portion is an arcuate curve bulging radially outward. Each convex portion defines a minimum radius. A difference between a radius R and the minimum radius is a depth Dh. Dhr=Dh×25.5/R. A range of an angular width A in relation to circumferential portion and a range of the depth Dh are set by the following expression, (5.6×Dhr+11.3)°×6/p?A<35°×6/p and A<[360/p?2×arccos]° ??(1) Therefore, decrease in torque is prevented. Torque pulsation is suppressed.

Abstract: A rotating electric machine including circumferential portions respectively corresponding to magnetic pole centers of permanent magnets and defined along the outer circumference of the rotor at a plurality of locations, with each circumferential portion extending along part of a virtual circumferential surface, which is coaxial with the rotor. The circumferential portions are spaced from one another in the circumferential direction. Convex portions connect adjacent pairs of the circumferential portions. Each convex portion is located radially inward from the circumferential surface, projects in a radially outward direction, and includes angled portions directed in the radially outward direction. The rotating electric machine suppresses decrease in the average value of the output torque and does not use reluctance torque to increase the average value of the output torque.

Abstract: An electric motor, which has a stator and a rotor including a permanent magnet, has a guide for guiding movably in an axial direction of the rotor and an actuator which is operable to move the rotor axially. In addition, a motor-driven compressor includes the electric motor for compressing and discharging gas in its compression chamber by compression of the compressor based upon rotation of its rotary shaft driven by the electric motor.