Rotary pump and brake device having the same

Abstract

A rotary pump includes a first side plate and a second side plate between which an outer rotor and an inner rotor are arranged. The second side plate has a concave portion on a surface adjacent to a maximum gap portion relative to a drive shaft. The concave portion is located in an outer teeth passing section which is defined between a line on which a teeth tip of an 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. The concave portion communicates with one of a plurality of gap portions while the inner rotor is rotated.

What is claimed is: 
     
         1 . 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 outer teeth passing section which is 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.   
     
     
         2 . The rotary pump according to  claim 1 , wherein
 the concave portion communicates with only one of the plurality of gap portions, and does not simultaneously communicate with two of the plurality of gap portions.   
     
     
         3 . The rotary pump according to  claim 1 , wherein
 the concave portion has a width dimension in a rotational direction, and the width dimension of the concave portion is smaller than a teeth width dimension of the outer teeth part and the inner teeth part in the rotational direction.   
     
     
         4 . The rotary pump according to  claim 1 , wherein
 the outer rotor has a center axis and the inner rotor has a center axis, a center line being defined by connecting the center axis of the outer rotor and the center axis of the inner rotor with each other, and   the concave portion is located adjacent to the discharge port with respect to the center line.   
     
     
         5 . A brake device comprising:
 the rotary pump according to  claim 1 ;   a brake fluid pressure generator which generates a brake fluid pressure based on a depression force;   a braking force generator which generates a braking force to a wheel based on the brake fluid pressure;   a main conduit connected to the brake fluid pressure generator to transmit the brake fluid pressure to the braking force generator; and   an auxiliary conduit connected to the brake fluid pressure generator to supply brake fluid to the main conduit so as to raise the braking force generated by the braking force generator, wherein   the rotary pump is arranged to draw the brake fluid at the intake port from the brake fluid pressure generator through the auxiliary conduit and to discharge the brake fluid at the discharge port toward the braking force generator through the main conduit.   
     
     
         6 . 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.   
     
     
         7 . The rotary pump according to  claim 6 , wherein
 the concave portion communicates with only one of the plurality of gap portions, and does not simultaneously communicate with two of the plurality of gap portions.   
     
     
         8 . The rotary pump according to  claim 6 , wherein
 the concave portion has a width dimension in a rotational direction, and the width dimension of the concave portion is smaller than a teeth width dimension of the outer teeth part and the inner teeth part in the rotational direction.   
     
     
         9 . The rotary pump according to  claim 6 , wherein
 the outer rotor has a center axis and the inner rotor has a center axis, a center line being defined by connecting the center axis of the outer rotor and the center axis of the inner rotor with each other, and   the concave portion is located adjacent to the discharge port with respect to the center line.   
     
     
         10 . A brake device comprising:
 the rotary pump according to  claim 6 ;   a brake fluid pressure generator which generates a brake fluid pressure based on a depression force;   a braking force generator which generates a braking force to a wheel based on the brake fluid pressure;   a main conduit connected to the brake fluid pressure generator to transmit the brake fluid pressure to the braking force generator; and   an auxiliary conduit connected to the brake fluid pressure generator to supply brake fluid to the main conduit so as to raise the braking force generated by the braking force generator, wherein   the rotary pump is arranged to draw the brake fluid at the intake port from the brake fluid pressure generator through the auxiliary conduit and to discharge the brake fluid at the discharge port toward the braking force generator through the main conduit.   
     
     
         11 . 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.   
     
     
         12 . The rotary pump according to  claim 11 , wherein
 the concave portion communicates with only one of the plurality of gap portions, and does not simultaneously communicate with two of the plurality of gap portions.   
     
     
         13 . The rotary pump according to  claim 11 , wherein
 the concave portion has a width dimension in a rotational direction, and the width dimension of the concave portion is smaller than a teeth width dimension of the outer teeth part and the inner teeth part in the rotational direction.   
     
     
         14 . The rotary pump according to  claim 11 , wherein
 the outer rotor has a center axis and the inner rotor has a center axis, a center line being defined by connecting the center axis of the outer rotor and the center axis of the inner rotor with each other, and   the concave portion is located adjacent to the discharge port with respect to the center line.   
     
     
         15 . A brake device comprising:
 the rotary pump according to  claim 11 ;   a brake fluid pressure generator which generates a brake fluid pressure based on a depression force;   a braking force generator which generates a braking force to a wheel based on the brake fluid pressure;   a main conduit connected to the brake fluid pressure generator to transmit the brake fluid pressure to the braking force generator; and   an auxiliary conduit connected to the brake fluid pressure generator to supply brake fluid to the main conduit so as to raise the braking force generated by the braking force generator, wherein   the rotary pump is arranged to draw the brake fluid at the intake port from the brake fluid pressure generator through the auxiliary conduit and to discharge the brake fluid at the discharge port toward the braking force generator through the main conduit.