JP2011032892A - Trochoid type rotary pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a trochoid type rotary pump locating an outer rotor at the center in a housing only by groove machining to the outer peripheral surface of the outer rotor. <P>SOLUTION: Oil grooves 12 are formed at fixed intervals in the outer peripheral surface 3b of the outer rotor 3. In the oil groove 12, right and left side portions 12a, 12a of the same are formed obliquely to lie upstream in a rotation direction 9 as advancing to the center from axial ends of the outer peripheral surface 3b of the outer rotor 3, and the oil groove has a V shape with a bottom 12b of the same lying uppermost stream in the rotation direction 9. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a trochoidal rotary pump including an inner rotor and an outer rotor, and more particularly to improvement of bias and inclination of an outer rotor.

  An automatic transmission mounted on a vehicle such as an automobile includes an oil pump that generates hydraulic pressure for various types of hydraulic control and supply of lubricating oil.

  In such an oil pump, an outer rotor that is rotatably accommodated in a rotor accommodating portion of a pump housing, and an inner rotor that has outer teeth meshing with the inner teeth of the outer rotor and is rotatably arranged in the outer rotor; A trochoidal rotary pump is employed in which a moving oil chamber is formed by the inner teeth and the outer teeth, and the oil sucked from the suction holes is compressed and pressurized and discharged from the discharge holes.

  In this type of trochoidal rotary pump, the outer rotor is pressed against the pump cover side or the pump housing side in the drive shaft direction by the discharge pressure, and is pressed against the suction side in the radial direction. There is a problem that bias and inclination occur.

  Due to the bias and inclination, there is a problem that the shear resistance of the oil film and metal wear increase, the driving torque of the oil pump increases, and the durability of the pump decreases.

  As a solution to the above-mentioned problem, for example, in Patent Document 1, a cylindrical member is interposed between the outer rotor and the housing, and ports (suction side and discharge side) are formed on the inner peripheral surface of the cylindrical member. A structure is disclosed in which an escape groove that communicates the pump chamber and the port is formed on the end face of the outer rotor. In this structure, the hydraulic pressure from the pump chamber is guided to the port to lubricate the outer periphery of the outer rotor, the opposing area of the intake side port is increased, and the outer rotor is pushed back to the discharge side.

  Further, in Patent Document 2, a plurality of oil reservoirs elongated in the axial direction are provided on the outer peripheral surface of the outer rotor at predetermined intervals in the circumferential direction, and a slight amount is provided between the end of the oil reservoir and the outer peripheral edge of the outer rotor. A structure is disclosed in which a land portion is provided and adjacent oil reservoirs are formed so as to overlap each other in the circumferential direction. In this structure, the lubricity of the sliding surface between the outer rotor and the housing is improved, and foreign matter is collected in the oil reservoir.

Japanese Utility Model Publication No. 6-73385 Japanese Utility Model Publication No. 6-28285

  However, the trochoidal rotary pump of Patent Document 1 requires complicated processing such as forming a port on the inner peripheral surface of the cylindrical member and forming a relief groove on the end surface of the outer rotor. There is a problem that it is difficult to set the facing area for positioning in the center.

  Further, in the trochoidal rotary pump of Patent Document 2, the outer rotor cannot be positioned at the center in the housing because of the structure. As a result, the outer rotor is biased and tilted, resulting in an increase in pump driving torque and a decrease in durability.

  The present invention has been made in view of the above-described conventional situation, and it is an object of the present invention to provide a trochoidal rotary pump capable of positioning the outer rotor at the center in the housing only by groove processing on the outer peripheral surface of the outer rotor. It is said.

  The invention of claim 1 includes a housing, an inner tooth, an outer rotor rotatably disposed in the housing, an outer tooth meshing with the inner tooth, the rotor being rotatable in the outer rotor, and the outer rotor. In a trochoidal rotary pump comprising an outer rotor rotating shaft and an eccentric inner rotor, oil grooves are formed at regular intervals on the outer circumferential surface of the outer rotor, and the oil grooves are axially arranged on the outer circumferential surface of the outer rotor. It is characterized by being formed obliquely so as to be located on the upstream side in the rotational direction from the end toward the center.

  According to a second aspect of the present invention, in the trochoidal rotary pump according to the first aspect, the oil groove has a V-shape whose bottom is positioned upstream in the rotational direction.

  According to the first aspect of the present invention, the oil grooves are formed at regular intervals on the outer peripheral surface of the outer rotor, and the oil grooves are positioned on the upstream side in the rotational direction from the axial end of the outer peripheral surface of the outer rotor toward the center. It is formed diagonally. Therefore, with the rotation of the outer rotor, the oil on the outer peripheral surface can be concentrated on the axial center of the outer peripheral surface of the outer rotor, and a certain oil film can be secured on the entire outer peripheral surface of the outer rotor. As a result, the bias and inclination of the outer rotor can be suppressed, and an increase in pump driving torque and a decrease in durability can be suppressed.

  Further, it is only necessary to perform groove processing on the outer peripheral surface of the outer rotor, the structure is simple, and the productivity is good.

  According to the second aspect of the present invention, the oil groove has a V shape whose bottom is located upstream in the rotation direction. Therefore, the oil on the outer peripheral surface is supplied to the outer periphery of the outer rotor as the outer rotor rotates. It is possible to concentrate more reliably on the axial center portion of the surface, and it is possible to further suppress the deviation and inclination of the outer rotor.

It is a front view of the trochoid rotary pump by Example 1 of this invention. It is a cross-sectional side view (II-II line cross-sectional view of FIG. 1) of the trochoid rotary pump. It is a front view of the housing of the trochoid rotary pump. It is a front view of the outer rotor of the trochoid rotary pump. It is a side view of the outer rotor. It is a side view which shows the shape of the oil groove of the outer peripheral surface of the said outer rotor. It is a front view which shows the shape of the oil groove of the said outer rotor outer peripheral surface. It is a perspective view of the outer rotor. FIG. 5 is a schematic diagram showing the flow of oil from both axial end portions of the outer rotor outer peripheral surface to the central portion. FIG. 3 is a schematic diagram illustrating a positional relationship in a radial direction of the outer rotor in a housing when hydraulic pressure is balanced in the first embodiment. FIG. 6 is a schematic diagram showing a positional relationship between the outer rotor in a radial direction and an axial direction in a housing when the hydraulic pressure is balanced. It is a perspective view of the outer rotor of the trochoid rotary pump by Example 2 of this invention.

  1 to 11 are diagrams for explaining a trochoidal rotary pump according to a first embodiment of the present invention.

  In the figure, reference numeral 1 denotes a trochoidal rotary pump. The pump 1 includes a housing 2, an outer rotor 3 disposed in a rotor chamber 2 a of the housing 2 so as to be rotatable about a rotation axis X, and the outer rotor 3. And an inner rotor 4 disposed so as to be rotatable around the rotation axis Y.

  The housing 2 includes a housing body 2b in which the rotor chamber 2a is recessed, and a housing cover 2c that is detachably attached thereto.

  The outer rotor 3 has a ring shape and has a plurality of inner teeth 3a that can seal all teeth. The inner rotor 4 has a ring shape, meshes with the inner teeth 3a, and has one fewer external teeth 4a than the inner teeth 3a. The inner rotor 4 is fitted to the drive shaft 5 and is fixed by a key 5a. The inner rotor 4 is assembled in the outer rotor 3 in a state where the rotation shaft Y of the drive shaft 5 is eccentric with respect to the rotation shaft X of the outer rotor 3. It has been.

  A plurality of closed gaps 10 a are formed by the inner teeth 3 a of the outer rotor 3, the outer teeth 4 a of the inner rotor 4, and the housing 2. As the inner rotor 4 rotates, the gap 10a gradually increases in the right portion of the straight line passing through the rotation axes X and Y of the outer rotor 3 and the inner rotor 4, and gradually decreases in the left portion. A suction port 6 and a discharge port 7 are formed in the right and left portions of the housing 2. The suction port 6 is connected to the suction passage 6a and communicates with the plurality of gap portions 10a 'in the right side portion. The discharge port 7 is connected to the discharge passage 7a and communicates with the plurality of gaps 10a '' on the left side portion.

  When the inner rotor 4 is rotationally driven around the rotational axis Y of the inner rotor 4 by the drive shaft 5, the outer rotor 3 is driven to rotate about the rotational axis X. Accordingly, the gap portion 10a 'in the right side portion gradually increases, and the gap portion 10a' 'in the left side portion gradually decreases.

  Of the plurality of gaps 10a, the gap 10a having the largest volume is formed at a position that does not communicate with either the suction port 6 or the discharge port 7. A differential pressure between the suction pressure and the discharge pressure at the discharge port 7 is maintained.

  A plurality of oil grooves 12 are formed at regular intervals on the outer peripheral surface 3 b of the outer rotor 3. The oil groove 12 has a V shape, and the left and right side portions 12a and 12a are located upstream of the rotational direction 9 from the axial end of the outer peripheral surface of the outer rotor 3 toward the center. Therefore, the bottom 12b is located on the most upstream side in the rotation direction 9. Further, both ends 12c, 12c of the oil groove 12 open to the left and right side surfaces 3c, 3c of the outer rotor 3 and face the rotor chamber 2a.

  When the inner rotor 4 and the outer rotor 3 rotate, the oil from the outside is sucked into the gap portion 10a ′ through the suction passage 6a and the suction port 6, and the oil in the gap portion 10a ″ is discharged into the discharge port 7 and It is discharged to the outside through the discharge passage 7a.

  Part of the oil sent to the discharge port 7 is guided from the discharge port 7 to the outer peripheral surface 3 b of the outer rotor 3 through the gap 11 between the outer rotor 3 and the rotor chamber 2 a of the housing 2.

  The oil guided to the outer peripheral surface 3b is guided in the direction of the arrow 13 (see FIG. 9) due to the centrifugal force accompanying the rotation of the outer rotor 3 and the oil groove 12 being V-shaped, so that the outer rotor 3 concentrates on the axial center part 14 of the outer peripheral surface, and forms a constant oil film over the entire circumference of the gap 11. This oil film keeps the hydraulic pressure balance in the radial direction constant and suppresses the radial deviation of the outer rotor 3 (see FIG. 10).

  Furthermore, a part of the oil supplied from the discharge port 7 to the gap 11 is maintained between the housing main body 2b and the outer rotor 3 via the oil groove 12 in a state where the hydraulic pressure balance in the radial direction is kept constant. It is supplied to the gap 15 between the side surface 3c and the gap 16 between the housing cover 2c and the side surface 3c of the outer rotor 3, respectively. Thereby, the hydraulic pressure balance in the axial direction in the gap 15 and the gap 16 is kept constant (see FIG. 11). As a result, the radial deviation of the outer rotor 3 is suppressed, and the axial deviation and inclination are suppressed.

  The oil grooves 12 formed at regular intervals on the outer peripheral surface 3b of the outer rotor 3 are not limited to V-shapes. FIG. 12 shows an outer rotor of a trochoidal rotary pump according to a second embodiment of the present invention. In the second embodiment, the oil groove 22 is formed obliquely on the outer peripheral surface 3b of the outer rotor 3 so as to be positioned on the upstream side in the rotational direction 9 as it goes from the axial end to the center. They are staggered at regular intervals.

  According to the present embodiment, the oil grooves 22 formed at regular intervals on the outer peripheral surface 3b of the outer rotor 3 are arranged upstream of the rotational direction 9 from the axial end of the outer peripheral surface 3b of the outer rotor 3 toward the center. Since the outer rotor 3 rotates, the oil on the outer peripheral surface 3 b concentrates on the axial center 14 of the outer peripheral surface 3 b of the outer rotor 3, and the outer rotor 3 has an outer periphery. A constant oil film can be secured over the entire circumference of the surface 3b, and the deviation and inclination of the outer rotor 3 can be suppressed.

DESCRIPTION OF SYMBOLS 1 Trochoidal rotary pump 2 Housing 3 Outer rotor 3a Inner tooth 3b Outer peripheral surface 4 Inner rotor 4a Outer tooth 12 Oil groove 12b Bottom X Outer rotor rotating shaft Y Inner rotor rotating shaft

Claims (2)

A housing, an inner rotor having an inner tooth, and an outer rotor rotatably disposed in the housing; and an outer tooth meshing with the inner tooth, the rotor being rotatable in the outer rotor and decentered from a rotation axis of the outer rotor In a trochoid rotary pump with an inner rotor arranged
Oil grooves are formed at regular intervals on the outer peripheral surface of the outer rotor,
The trochoidal rotary pump is characterized in that the oil groove is formed obliquely so as to be positioned on the upstream side in the rotational direction from the axial end of the outer peripheral surface of the outer rotor toward the center. The trochoidal rotary pump according to claim 1,
The trochoid rotary pump characterized in that the oil groove has a V-shape whose bottom is located upstream in the rotational direction.

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