Rotary pump and brake device having the same

A rotary pump comprising:

• a rotary portion including an outer rotor having an inner teeth part on an inner perimeter, an inner rotor having an outer teeth part on an outer perimeter, the inner rotor having a rotation axis corresponding to a drive shaft, a plurality of gap portions being defined between the inner teeth part and the outer teeth part and having a maximum gap portion which has a maximum volume among the plurality of gap portions;
• a casing covering the rotary portion and having
• a first side plate and a second side plate between which the outer rotor and the inner rotor are arranged, the second side plate having a contact surface in contact with the outer rotor and the inner rotor so as to achieve a mechanical sealing, and
• a central plate arranged to surround an outer perimeter of the outer rotor, the casing having an intake port through which fluid is drawn toward the rotary portion and a discharge port through which fluid is discharged from the rotary portion;
• and
• a seal component arranged between the first side plate and the rotary portion to define a low pressure part connected to the intake port and a high pressure part connected to the discharge port, wherein
• the second side plate has a concave portion on the contact surface adjacent to the maximum gap portion relative to the drive shaft,
• the concave portion is located in an inner teeth passing section which is defined between a line on which a teeth tip of the inner teeth part of the outer rotor passes in response to rotation of the outer rotor and a line on which a teeth bottom of the inner teeth part of the outer rotor passes in response to rotation of the outer rotor, and
• the concave portion communicates with one of the plurality of gap portions while the inner rotor is rotated.

A rotary pump comprising:

• a rotary portion including an outer rotor having an inner teeth part on an inner perimeter, an inner rotor having an outer teeth part on an outer perimeter, the inner rotor having a rotation axis corresponding to a drive shaft, a plurality of gap portions being defined between the inner teeth part and the outer teeth part and having a minimum gap portion which has a minimum volume among the plurality of gap portions;
• a casing covering the rotary portion and having
• a first side plate and a second side plate between which the outer rotor and the inner rotor are arranged, the second side plate having a contact surface in contact with the outer rotor and the inner rotor so as to achieve a mechanical sealing, and
• a central plate arranged to surround an outer perimeter of the outer rotor, the casing having an intake port through which fluid is drawn toward the rotary portion and a discharge port through which fluid is discharged from the rotary portion;
• and
• a seal component arranged between the first side plate and the rotary portion to define a low pressure part connected to the intake port and a high pressure part connected to the discharge port, wherein
• the second side plate has a concave portion on the contact surface adjacent to the minimum gap portion relative to the drive shaft,
• the concave portion is located in an overlap area in which an inner teeth passing section and an outer teeth passing section are overlapped with each other, the inner teeth passing section being defined between a line on which a teeth tip of the inner teeth part of the outer rotor passes in response to rotation of the outer rotor and a line on which a teeth bottom of the inner teeth part of the outer rotor passes in response to rotation of the outer rotor, the outer teeth passing section being defined between a line on which a teeth tip of the outer teeth part of the inner rotor passes in response to rotation of the inner rotor and a line on which a teeth bottom of the outer teeth part of the inner rotor passes in response to rotation of the inner rotor, and
• the concave portion communicates with one of the plurality of gap portions while the inner rotor is rotated.