Gear pump device

Abstract

To provide a gear pump device which efficiently increases an oil film pressure in a gap between a section projection part and a rotor unit in one example.SOLUTION: A gear pump device according to the embodiment includes: a rotor unit having an inner gear and an outer gear; and a housing having a wall provided with a rotor chamber for storing the rotor unit and positioned away from the rotor unit in an axial direction along the rotational shaft and a partition projection part projecting from the wall toward the rotor unit and that partitions the rotor chamber into a low pressure region and a high pressure region. The partition projection part includes at least one groove with a cross section decreasing toward a low-pressure side direction or a shrinking direction which is a direction between a rotation direction and the low-pressure side direction, and away from the low-pressure region and the high-pressure region.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a gear pump device. [Background technology]

[0002] A gear pump device including a rotor unit and a housing is known. The gear pump device rotates an inner gear and an outer gear of the rotor unit to transfer fluid between the meshing external teeth of the inner gear and the meshing internal teeth of the outer gear from a low-pressure region to a high-pressure region.

[0003] The housing accommodates the rotor unit. The housing has a partition protrusion that protrudes from the wall toward the rotor unit and separates the low-pressure region from the high-pressure region. A small gap is provided between the partition protrusion and the rotor unit to prevent direct contact between the partition protrusion and the rotor unit.

[0004] The dividing convex portion may have, for example, a generally V-shaped groove tapering in the rotation direction of the inner gear and the outer gear. When the fluids collide with each other at the tip of the groove, the pressure in the gap increases (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-116797 Summary of the Invention [Problem to be solved by the invention]

[0006] However, because of the pressure difference between the high-pressure and low-pressure regions, the direction of fluid flow in the gap does not match the direction of rotation of the inner gear and outer gear, and therefore does not match the direction of tapering of the groove. As a result, in conventional configurations, the collision of fluid at the tip of the groove may be weak.

[0007] Therefore, the present invention has been made in consideration of the above, and provides a gear pump device that can efficiently increase the oil film pressure in the gap between the partition convex portion and the rotor unit. [Means for solving the problem]

[0008] As an example, a gear pump device according to an embodiment of the present invention includes a rotor unit having an inner gear rotatable about a rotation axis and an outer gear surrounding the inner gear, wherein a plurality of external teeth provided on the inner gear mesh with a plurality of internal teeth provided on the outer gear, a rotor chamber accommodating the rotor unit, an intake passage communicating with the rotor chamber, and a discharge passage communicating with the rotor chamber, and includes a wall spaced from the rotor unit in an axial direction along the rotation axis, and a low-pressure region communicating with the intake passage and a high-pressure region communicating with the discharge passage, the wall protruding from the wall toward the rotor unit. The rotor unit includes a housing having a partitioning protrusion that partitions the high-pressure region, and at least a portion of the low-pressure region is spaced from the high-pressure region in a low-pressure direction, which is either radially inward or radially outward, perpendicular to the rotation axis. When the inner gear rotates in a rotational direction around the rotation axis, the rotor unit transports fluid in a gap between the plurality of external teeth and the plurality of internal teeth from the low-pressure region to the high-pressure region. The partitioning protrusion has at least one groove whose cross-sectional area decreases in a reduction direction, which is either the low-pressure direction or a direction between the rotational direction and the low-pressure direction, and which is spaced from the low-pressure region and the high-pressure region. Thus, for example, when the inner gear and the outer gear rotate in the rotational direction, the fluid flows in the rotational direction. Meanwhile, when the fluid is transported from the low-pressure region to the high-pressure region, the pressure in the high-pressure region increases, creating a pressure difference between the high-pressure region and the low-pressure region. Due to this pressure difference, the fluid in the high-pressure region also flows into the low-pressure region through a gap between the partitioning protrusion and the rotor unit. That is, in the gap, the fluid flows in a contraction direction, which is the low-pressure side direction or a direction between the rotation direction and the low-pressure side direction. In the gap, the fluid flows through the groove and converges in the contraction direction. When the fluids collide with each other at the ends of the groove in the contraction direction, the oil film pressure in the gap increases, and the distance between the partition convex portion and the rotor unit is maintained. Because the fluid flows in the contraction direction, the cross-sectional area of ​​the groove decreases in the contraction direction, and the groove does not communicate with either the low-pressure region or the high-pressure region, the gear pump device can efficiently increase the oil film pressure in the gap. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing a gear pump device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a part of the gear pump device of the first embodiment taken along line F2-F2 in FIG. [Figure 3] FIG. 3 is a cross-sectional view schematically showing a part of the gear pump device of the first embodiment taken along line F3-F3 in FIG. [Figure 4] FIG. 4 is a front view showing the ring seal of the first embodiment. [Figure 5] FIG. 5 is a front view showing a part of the ring seal of the first embodiment. [Figure 6] FIG. 6 is a front view showing a part of the rotor unit of the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a part of a gear pump device according to a second embodiment. [Figure 8] FIG. 8 is a front view showing a part of the ring seal according to the first modified example. [Figure 9] FIG. 9 is a front view showing a part of a ring seal according to a second modified example. [Figure 10] FIG. 10 is a front view showing a part of a ring seal according to a third modified example. [Figure 11] FIG. 11 is a front view showing a part of a ring seal according to a fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) The first embodiment will be described below with reference to FIGS. 1 to 6. In this specification, components according to the embodiment and descriptions of the components may be described using multiple expressions. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. Furthermore, the components may also be described using expressions different from those in this specification.

[0011] In the following description, "inhibit" is defined as, for example, preventing an event, action, or effect from occurring or reducing the magnitude of an event, action, or effect.

[0012] Fig. 1 is a cross-sectional view showing a gear pump device 10 of a first embodiment. Fig. 2 is a cross-sectional view showing a part of the gear pump device 10 of the first embodiment, taken along line F2-F2 in Fig. 1. As shown in Fig. 2, the gear pump device 10 of this embodiment is an internal gear pump (trochoid pump). The gear pump device 10 has a shaft 11, a rotor unit 12, a key 13, a housing 14, and a plurality of outer circumferential seals 15.

[0013] As shown in Fig. 1, the shaft 11 is formed in a generally cylindrical shape extending approximately along a first central axis Ax1. The first central axis Ax1 is an example of a rotation axis. The first central axis Ax1 is the central axis of the shaft 11. However, the first central axis Ax1 is not limited to this example.

[0014] The shaft 11 is mainly made of metal. However, the shaft 11 may be made of other materials. The shaft 11 is rotated in a first circumferential direction Dc1 about a first central axis Ax1 by a power source such as a motor. The first circumferential direction Dc1 is an example of a rotational direction and a first circumferential direction.

[0015] For convenience, the terms axial direction, radial direction, and circumferential direction are defined herein. The axial direction is a direction along the first central axis Ax1. The radial direction is a direction perpendicular to the first central axis Ax1. The circumferential direction is a direction around the first central axis Ax1. The first circumferential direction Dc1 is included in the circumferential direction.

[0016] As shown in FIG. 2, the rotor unit 12 has an inner gear 21 and an outer gear 22. The inner gear 21 may also be referred to as an inner rotor. The outer gear 22 may also be referred to as an outer rotor. The inner gear 21 and the outer gear 22 are mainly made of a metal such as iron. However, the inner gear 21 and the outer gear 22 may also be made of other materials.

[0017] Fig. 3 is a cross-sectional view schematically showing a portion of the gear pump device 10 of the first embodiment taken along line F3-F3 in Fig. 2. As shown in Fig. 3, the inner gear 21 is formed in a substantially disk shape. The first central axis Ax1 is also, for example, the central axis of the inner gear 21. The inner gear 21 has two side surfaces 21a and an outer peripheral surface 21b.

[0018] The two side surfaces 21a are provided on both axial ends of the inner gear 21. The side surfaces 21a are formed to be approximately flat and face the axial direction. The outer peripheral surface 21b is a curved surface having an approximately cylindrical shape that extends in the circumferential direction and faces radially outward.

[0019] As shown in FIG. 1 , the inner gear 21 is provided with an insertion hole 23 and a key groove 24. The insertion hole 23 extends along the first central axis Ax1 and passes through the inner gear 21 in the axial direction. The shaft 11 extends axially through the insertion hole 23. In other words, the shaft 11 passes through the insertion hole 23. The key groove 24 is recessed radially outward from the insertion hole 23.

[0020] 2, a plurality of external teeth 25 are provided on an outer peripheral surface 21b of the inner gear 21. The external teeth 25 protrude radially outward from the outer peripheral surface 21b and are arranged in the circumferential direction. The outer peripheral surface 21b forms the tooth bottoms of the external teeth 25.

[0021] The outer gear 22 is formed in a generally annular shape extending around a second central axis Ax2. That is, the second central axis Ax2 is the central axis of the outer gear 22. The second central axis Ax2 extends generally parallel to the first central axis Ax1 and is slightly spaced radially from the first central axis Ax1. Therefore, the axial direction is also the direction extending along the second central axis Ax2. The radial direction is roughly equal to the direction perpendicular to the second central axis Ax2. The circumferential direction is roughly equal to the direction of rotation around the second central axis Ax2.

[0022] The outer gear 22 surrounds the inner gear 21. In other words, the inner gear 21 is located inside the outer gear 22. As shown in Fig. 3, the outer gear 22 has two side surfaces 22a, an inner peripheral surface 22b, and an outer peripheral surface 22c.

[0023] The two side surfaces 22a are provided on both axial ends of the outer gear 22. The side surfaces 22a are formed substantially flat and face the axial direction. The side surfaces 22a of the outer gear 22 are positioned substantially flush with the side surfaces 21a of the inner gear 21.

[0024] As shown in Fig. 2, the inner circumferential surface 22b is a substantially cylindrical curved surface extending around the second central axis Ax2 and facing inward in the radial direction. The inner circumferential surface 22b faces the outer circumferential surface 21b of the inner gear 21 via a gap. The outer circumferential surface 22c is located on the opposite side of the inner circumferential surface 22b and is a substantially cylindrical curved surface extending around the second central axis Ax2. The outer circumferential surface 22c faces outward in the radial direction.

[0025] A plurality of internal teeth 27 are provided on the inner peripheral surface 22b of the outer gear 22. The internal teeth 27 protrude from the inner peripheral surface 22b and are arranged in the circumferential direction. Therefore, the inner peripheral surface 22b forms the tooth bottoms of the internal teeth 27. The multiple internal teeth 27 mesh with the multiple external teeth 25.

[0026] A plurality of gaps 29 are provided between the plurality of external teeth 25 and the plurality of internal teeth 27. The inner gear 21 on which the external teeth 25 are provided is eccentric with respect to the outer gear 22 on which the internal teeth 27 are provided. Therefore, the sizes of the plurality of gaps 29 are different from one another.

[0027] The key 13 is attached to the shaft 11 and protrudes radially outward from the shaft 11. The key 13 fits into the key groove 24. This allows the key 13 to transmit the rotation of the shaft 11 to the inner gear 21. In other words, the inner gear 21 can rotate integrally with the shaft 11 around the first central axis Ax1.

[0028] 1, the housing 14 includes a cylinder 31, a plug 32, a casing 33, and two ring seals 34. The cylinder 31, the plug 32, and the casing 33 are aligned in the axial direction. The casing 33 is located between the cylinder 31 and the plug 32.

[0029] The casing 33 is formed in a generally annular shape extending around the second central axis Ax2. The casing 33 has an inner circumferential surface 33a. The inner circumferential surface 33a is a generally cylindrical curved surface extending around the second central axis Ax2 and facing inward in the generally radial direction.

[0030] The housing 14 is provided with a rotor chamber 35, a suction passage 36, and a discharge passage 37. The rotor chamber 35 is provided inside the housing 14. The rotor chamber 35 is defined by the cylinder 31, the plug 32, and an inner circumferential surface 33a of the casing 33. A portion of the shaft 11 and the rotor unit 12 are housed in the rotor chamber 35.

[0031] The suction passage 36 and the discharge passage 37 are provided in the cylinder 31 and communicate with the rotor chamber 35. The discharge passage 37 is spaced apart from the suction passage 36 in a substantially radial direction. In the radial direction, the first central axis Ax1, the second central axis Ax2, and the shaft 11 are located between the suction passage 36 and the discharge passage 37. Note that the positions of the suction passage 36 and the discharge passage 37 are not limited to this example.

[0032] 2, the rotor unit 12 is disposed inside the inner circumferential surface 33a. Therefore, the inner circumferential surface 33a of the casing 33 faces the outer circumferential surface 22c of the outer gear 22. The diameter of the inner circumferential surface 33a is larger than the diameter of the outer circumferential surface 22c.

[0033] Two recesses 38 are provided in the casing 33. The recesses 38 are recessed from the inner peripheral surface 33a of the casing 33 at positions spaced apart from each other in the circumferential direction and communicate with the rotor chamber 35. The recesses 38 open toward the outer peripheral surface 22c of the outer gear 22 housed in the rotor chamber 35.

[0034] 1, one of the two ring seals 34 is located between the cylinder 31 and the rotor unit 12. The other of the two ring seals 34 is located between the plug 32 and the rotor unit 12. Therefore, the rotor unit 12 is located between the two ring seals 34. The two ring seals 34 are formed in mirror symmetry with respect to a virtual plane that is approximately perpendicular to the first central axis Ax1.

[0035] 3, the ring seal 34 is mainly made of a metal such as iron. However, the ring seal 34 may be made of other materials such as synthetic resin. The ring seal 34 has a wall 41, an outer peripheral protrusion 42, and a partition protrusion 43.

[0036] The wall 41 is formed in a disk shape that is approximately perpendicular to the first central axis Ax1. The wall 41 is spaced apart in the axial direction from the rotor unit 12. The wall 41 has a side surface 41a. The side surface 41a is formed to be approximately flat and faces the axial direction. The side surface 41a faces the side surface 21a of the inner gear 21 and the side surface 22a of the outer gear 22 via a gap.

[0037] 4 is a front view showing the ring seal 34 of the first embodiment. As shown in FIG. 4, a wall 41 is provided with an insertion hole 45, an intake port 46, and a plurality of discharge ports 47. The insertion hole 45 penetrates the wall 41 in the axial direction along the first central axis Ax1 and opens to the side surface 41a. The shaft 11 extends through the insertion hole 45.

[0038] The suction port 46 and the discharge port 47 each penetrate the wall 41 in the axial direction and open to the side surface 41a. The suction port 46 communicates with the suction passage 36 of the cylinder 31. The discharge port 47 communicates with the discharge passage 37 of the cylinder 31.

[0039] The outer peripheral protrusion 42 protrudes from the edge of the side surface 41a of the wall 41 on the radially outer side toward the casing 33. The outer peripheral protrusion 42 is formed in a substantially annular shape extending around the second central axis Ax2. The outer peripheral protrusion 42 of the ring seal 34 abuts against the casing 33. Note that the outer peripheral protrusion 42 may be slightly spaced from the casing 33.

[0040] As shown in Fig. 3, the partitioning protrusion 43 protrudes from the side surface 41a of the wall 41 toward the rotor unit 12. The partitioning protrusion 43 has a sealing surface 43a. The sealing surface 43a is located at the end of the partitioning protrusion 43 in the axial direction and faces the rotor unit 12 via a small gap G. Note that the sealing surface 43a may temporarily come into contact with the rotor unit 12.

[0041] 4, the partitioning protrusion 43 extends in a substantially C-shape so as to surround the shaft 11 and the insertion hole 45. Both ends of the partitioning protrusion 43 are connected to the outer peripheral protrusion 42. The partitioning protrusion 43 has an upstream portion 51, a downstream portion 52, and a land portion 53. Each of the upstream portion 51, the downstream portion 52, and the land portion 53 is part of the partitioning protrusion 43, and partially has a sealing surface 43a.

[0042] The upstream portion 51 and the downstream portion 52 each extend from the outer peripheral convex portion 42. In the circumferential direction, the upstream portion 51 and the downstream portion 52 are each located between the suction port 46 and the discharge port 47. The land portion 53 extends in a substantially arc shape around the first central axis Ax1 between the upstream portion 51 and the downstream portion 52. In the radial direction, the land portion 53 is located between the insertion hole 45 and the discharge port 47, and is spaced apart from the shaft 11 and the insertion hole 45.

[0043] 2, the partitioning protrusion 43 divides the rotor chamber 35 into a low-pressure region 35L and a high-pressure region 35H between the wall 41 and the rotor unit 12. As shown in FIG. 1, the low-pressure region 35L communicates with the suction passage 36. The high-pressure region 35H communicates with the discharge passage 37.

[0044] 2, in this embodiment, the shaft 11 and the insertion holes 23, 45 are provided in the low pressure region 35L. The shaft 11 and the insertion holes 23, 45 may also be provided in the high pressure region 35H.

[0045] The portion of the low-pressure region 35L near the shaft 11 and the insertion holes 23, 45 is spaced radially inward from the high-pressure region 35H. Hereinafter, the radially inward direction will be referred to as the low-pressure side direction Dl. The radially outward direction will be referred to as the high-pressure side direction Dh. The high-pressure side direction Dh is the opposite direction to the low-pressure side direction Dl. In the radial direction, the land portion 53 is located between the low-pressure region 35L and the high-pressure region 35H. Note that at least a portion of the low-pressure region 35L may be spaced radially outward from the high-pressure region 35H. In this case, the low-pressure side direction Dl is the radially outward direction.

[0046] The low pressure region 35L and the high pressure region 35H may communicate with each other through a gap G. However, the gap G is set to be narrow so that a pressure difference between the low pressure region 35L and the high pressure region 35H can be maintained while the gear pump device 10 is in operation.

[0047] 2, the multiple external teeth 25 of the inner gear 21 and the multiple internal teeth 27 of the outer gear 22 are arranged across the low-pressure region 35L and the high-pressure region 35H. Therefore, the external teeth 25 and the internal teeth 27 circulate between the low-pressure region 35L and the high-pressure region 35H as the inner gear 21 and the outer gear 22 rotate.

[0048] When the shaft 11 rotates the inner gear 21 in the first circumferential direction Dc1, the outer gear 22 also rotates approximately in the first circumferential direction Dc1 around the second central axis Ax2 due to the meshing of the external teeth 25 and the internal teeth 27. As a result, the gap 29 between the external teeth 25 and the internal teeth 27 moves approximately in the first circumferential direction Dc1 while expanding and contracting. As a result, the gap 29 moves from the low-pressure region 35L to the high-pressure region 35H.

[0049] A fluid such as brake fluid is supplied from the intake passage 36 through the intake port 46 to the low-pressure region 35L. The brake fluid flows into the gap 29 in the low-pressure region 35L. As the inner gear 21 and the outer gear 22 rotate in the first circumferential direction Dc1, the rotor unit 12 transports the fluid in the gap 29 from the low-pressure region 35L to the high-pressure region 35H. The brake fluid transported to the high-pressure region 35H is discharged from the gap 29 through the discharge port 47 to the discharge passage 37.

[0050] The rotor chamber 35 further includes a first boundary region 35B1 and a second boundary region 35B2. The first boundary region 35B1 and the second boundary region 35B2 are located between the low pressure region 35L and the high pressure region 35H. The first boundary region 35B1 and the second boundary region 35B2 are spaced apart from each other in the circumferential direction.

[0051] The first boundary region 35B1 includes, among the gaps 29 moving in the first circumferential direction Dc1 from the low pressure region 35L to the high pressure region 35H, the gaps 29 located between the upstream portions 51 of the partitioning protrusions 43 of the two ring seals 34. The seal surfaces 43a of the upstream portions 51 face the first boundary region 35B1. The volume of the gaps 29 is greatest in the first boundary region 35B1.

[0052] The second boundary region 35B2 includes, among the gaps 29 that move from the high-pressure region 35H to the low-pressure region 35L in the first circumferential direction Dc1, the gaps 29 that are located between the downstream portions 52 of the partitioning protrusions 43 of the two ring seals 34. The seal surfaces 43a of the downstream portions 52 face the second boundary region 35B2. In the second boundary region 35B2, the volume of the gaps 29 is minimum.

[0053] In the first boundary region 35B1, the side surfaces 21a of the external teeth 25 of the inner gear 21 and the side surfaces 22a of the internal teeth 27 of the outer gear 22 face the upstream portion 51 of the partitioning protrusion 43 via a gap G. In addition, in the second boundary region 35B2, the side surfaces 21a of the external teeth 25 and the side surfaces 22a of the internal teeth 27 face the downstream portion 52 of the partitioning protrusion 43 via a gap G.

[0054] Each of the two recesses 38 houses one of the two outer circumferential seals 15. The two recesses 38 and the two outer circumferential seals 15 are each located between the low pressure region 35L and the high pressure region 35H in the circumferential direction.

[0055] Each of the two peripheral seals 15 includes a seal member 61 and an elastic body 62. The seal member 61 may also be called a chip seal. The elastic body 62 may also be called a chip ball.

[0056] The seal member 61 is made of, for example, synthetic resin, but the material of the seal member 61 is not limited to this example. The seal member 61 is formed in the shape of a block having a substantially triangular cross section.

[0057] The elastic body 62 is made of an elastomer such as synthetic rubber. The elastic body 62 is not limited to this example and may be another elastic body such as a coil spring. The elastic body 62 of this embodiment is formed in a substantially spherical or substantially ellipsoidal shape. The shape of the elastic body 62 is not limited to this example and may be formed in, for example, a substantially cylindrical shape.

[0058] The seal member 61 is interposed between the outer gear 22 and the elastic body 62. The elastic body 62 is compressed between the casing 33 and the seal member 61, and presses the seal member 61 toward the outer peripheral surface 22c of the outer gear 22 by its elastic force.

[0059] The seal member 61 abuts against the outer peripheral surface 22c, thereby sealing the low pressure region 35L and the high pressure region 35H between the outer peripheral surface 22c of the outer gear 22 and the inner peripheral surface 33a of the casing 33. The seal member 61 and the outer peripheral surface 22c may be slightly spaced apart, for example, via brake fluid.

[0060] The two recesses 38 are spaced apart from each other at an angle less than 180° around the second central axis Ax2, so that the two outer circumferential seals 15 press the outer gear 22 approximately toward the contact point P in FIG.

[0061] At contact point P, the outer peripheral surface 22c of the outer gear 22 contacts the inner peripheral surface 33a of the casing 33. The position of contact point P is determined by, for example, the differential pressure (discharge pressure) between the low pressure region 35L and the high pressure region 35H and the force with which the two outer peripheral seals 15 press against the outer gear 22.

[0062] Fig. 5 is a front view showing a portion of the ring seal 34 of the first embodiment. As shown in Fig. 5, a plurality of grooves 70 are provided on the sealing surface 43a of the land portion 53 of the partitioning protrusion 43. Therefore, the grooves 70 communicate with the gap G. The grooves 70 may also be referred to as texturing.

[0063] The groove 70 is provided in the sealing surface 43a by, for example, laser processing. The groove 70 may be formed by other methods. The length (depth) of the groove 70 in the axial direction is smaller than the length of the gap G.

[0064] Each of the plurality of grooves 70 is formed in a substantially V-shape. That is, each of the plurality of grooves 70 has two linear portions 71, 72. Each of the linear portions 71, 72 is a groove that extends linearly along the sealing surface 43a. One end of the linear portion 71 and one end of the linear portion 72 are connected to each other.

[0065] The two straight portions 71, 72 extend such that the groove 70 tapers in a first reduction direction Dr1 in FIG. 5. That is, the cross-sectional area of ​​the groove 70 reduces in the first reduction direction Dr1. The first reduction direction Dr1 is an example of a reduction direction. In the example of FIG. 5, the first reduction direction Dr1 is a direction between the first circumferential direction Dc1 and the low-pressure side direction Dl. Note that the first reduction direction Dr1 may also be the low-pressure side direction Dl. That is, the angle θ1 between the first reduction direction Dr1 and the first circumferential direction Dc1 is greater than 0° and less than or equal to 90°.

[0066] As described above, the first circumferential direction Dc1 is a direction around the first central axis Ax1. As shown in Fig. 5, the first circumferential direction Dc1 for one groove 70 is also a direction perpendicular to a virtual line connecting the groove 70 and the first central axis Ax1.

[0067] The plurality of grooves 70 form a plurality of rows 75. In the example of Fig. 5, each of the plurality of rows 75 includes five grooves 70. However, the number of rows 75 is not limited to this example. The plurality of rows 75 are arranged at approximately equal intervals in the circumferential direction.

[0068] In each of the multiple rows 75, the multiple grooves 70 are aligned in the first reduction direction Dr1. Furthermore, two adjacent rows 75 overlap in the first reduction direction Dr1. In other words, a portion of one groove 70 and a portion of another groove 70 are disposed at the same position in the first reduction direction Dr1.

[0069] The seal surface 43a is divided into three equal regions R1, R2, and R3 in the radial direction as shown in Figure 5. Region R1 has an edge 43b of the seal surface 43a in the low-pressure side direction Dl. Region R2 has an edge 43c of the seal surface 43a in the high-pressure side direction Dh. Region R3 is located between the two regions R1 and R2.

[0070] The grooves 70 are provided in the regions R1 and R3. Therefore, the distance between the edge 43b of the seal surface 43a and the grooves 70 in the low-pressure side direction Dl is shorter than the distance between the edge 43c of the seal surface 43a and the grooves 70 in the high-pressure side direction Dh.

[0071] The grooves 70 are spaced apart from the edges 43b, 43c of the sealing surface 43a. That is, the grooves 70 are spaced apart from the low pressure region 35L and the high pressure region 35H and do not directly communicate with either the low pressure region 35L or the high pressure region 35H. However, the grooves 70 indirectly communicate with the low pressure region 35L and the high pressure region 35H through the gap G.

[0072] Fig. 6 is a front view showing a portion of the rotor unit 12 of the first embodiment. As shown in Fig. 6, a plurality of grooves 80 are provided on the side surfaces 21a of the external teeth 25 of the inner gear 21 and the side surfaces 22a of the internal teeth 27 of the outer gear 22. Therefore, the grooves 80 communicate with the gap G, for example, in the first boundary region 35B1 and the second boundary region 35B2. The grooves 80 may also be referred to as texturing.

[0073] The grooves 80 are provided in the side surfaces 21a, 22a by, for example, laser processing. The grooves 80 may be formed by other methods. The length (depth) of the grooves 80 in the axial direction is smaller than the length of the gap G.

[0074] Each of the plurality of grooves 80 is formed in a substantially V-shape. That is, each of the plurality of grooves 80 has two linear portions 81, 82. Each of the linear portions 81, 82 is a groove that extends linearly along the sealing surface 43a. One end of the linear portion 81 and one end of the linear portion 82 are connected to each other.

[0075] The two straight line portions 81, 82 extend such that the groove 80 tapers in the second reduction direction Dr2 in FIG. 6. That is, the cross-sectional area of ​​the groove 80 reduces in the second reduction direction Dr2. In the example of FIG. 6, the second reduction direction Dr2 is a direction between the second circumferential direction Dc2 and the low-pressure side direction Dl. The second circumferential direction Dc2 is the opposite direction to the first circumferential direction Dc1. Note that the second reduction direction Dr2 may be the low-pressure side direction Dl. That is, the angle θ2 between the second reduction direction Dr2 and the second circumferential direction Dc2 is greater than 0° and less than or equal to 90°.

[0076] The plurality of grooves 80 form a plurality of rows 85. In the example of FIG. 6, each of the plurality of rows 85 includes five grooves 80. However, the rows 85 are not limited to this example. In each of the plurality of external teeth 25 and the plurality of internal teeth 27, the plurality of rows 85 are arranged at approximately equal intervals in the circumferential direction. In each of the plurality of rows 85, the plurality of grooves 80 are aligned in the second reduction direction Dr2. Furthermore, two adjacent ones of the plurality of rows 85 overlap in the second reduction direction Dr2.

[0077] The grooves 80 are spaced apart from the edges of the side surfaces 21 a of the external teeth 25 and the edges of the side surfaces 22 a of the internal teeth 27. In addition, the length of each of the grooves 80 in the circumferential direction is shorter than the length of the first boundary region 35B1 and shorter than the length of the second boundary region 35B2.

[0078] At the boundary between low pressure region 35L and first boundary region 35B1, groove 80 communicates with low pressure region 35L but is spaced apart from high pressure region 35H. At the boundary between high pressure region 35H and first boundary region 35B1, groove 80 communicates with high pressure region 35H but is spaced apart from low pressure region 35L.

[0079] At the boundary between low pressure region 35L and second boundary region 35B2, groove 80 communicates with low pressure region 35L but is spaced apart from high pressure region 35H. At the boundary between high pressure region 35H and second boundary region 35B2, groove 80 communicates with high pressure region 35H but is spaced apart from low pressure region 35L.

[0080] As described above, each of the multiple grooves 80 is separated from at least one of the low pressure region 35L and the high pressure region 35H. That is, each of the multiple grooves 80 does not simultaneously and directly communicate with both the low pressure region 35L and the high pressure region 35H.

[0081] The plurality of grooves 70 and the plurality of grooves 80 are spaced apart from each other. In the present embodiment, the plurality of grooves 80 are farther away from the first central axis Ax1 than the plurality of grooves 70. Note that at least one of the plurality of grooves 70 and at least one of the plurality of grooves 80 may be in communication with each other through a gap G.

[0082] Brake fluid is present not only in the low pressure region 35L, the high pressure region 35H, the first boundary region 35B1, and the second boundary region 35B2, but also in the gap G. The brake fluid in the gap G generates an oil film pressure, which can keep the rotor unit 12 and the partition protrusion 43 spaced apart from each other.

[0083] When the inner gear 21 and the outer gear 22 rotate in the first circumferential direction Dc1, the inner gear 21 and the outer gear 22 push (pull) the brake fluid present in the gap G in the first circumferential direction Dc1. This can cause the brake fluid to flow in the first circumferential direction Dc1 in the gap G.

[0084] On the other hand, the pressure in the high-pressure region 35H is higher than the pressure in the low-pressure region 35L. This creates a pressure difference between the high-pressure region 35H and the low-pressure region 35L. This pressure difference causes the brake fluid in the high-pressure region 35H to flow through the gap G to the low-pressure region 35L. That is, a flow of brake fluid in the low-pressure direction Dl can occur in the gap G. Note that because the gap G is narrow, the flow of brake fluid from the high-pressure region 35H to the low-pressure region 35L is small.

[0085] 5, a flow of brake fluid occurs in the first circumferential direction Dc1 and a flow of brake fluid in the low-pressure side direction Dl, and therefore a flow Ff of brake fluid occurs in the gap G in the first narrowing direction Dr1. That is, in the gap G, the brake fluid flows along the multiple grooves 70.

[0086] Brake fluid flows through the multiple grooves 70. Therefore, the brake fluid flowing through the straight portion 71 and the brake fluid flowing through the straight portion 72 collide with each other at the tip ends 70a of the grooves 70 in the first reduction direction Dr1. The collision of the brake fluids increases the oil film pressure in the gap G.

[0087] The plurality of grooves 70 are aligned in the first contraction direction Dr1 and overlap with the first contraction direction Dr1, so that the brake fluids collide with each other multiple times in the first contraction direction Dr1, causing a cumulative increase in oil film pressure.

[0088] The cross-sectional area of ​​the groove 70 decreases in the first direction Dr1, and the brake fluid flows in the first direction Dr1. As a result, the brake fluids collide strongly with each other at the tip 70a, and the oil film pressure increases efficiently.

[0089] The first reduction direction Dr1 is set, for example, according to the normal rotation speed of the inner gear 21 and the outer gear 22. When the normal rotation speed of the inner gear 21 and the outer gear 22 is slow, the first reduction direction Dr1 can coincide with the low-pressure side direction Dl. The first reduction direction Dr1 does not have to completely coincide with the direction in which the brake fluid flows.

[0090] When the gear pump device 10 is driven, the ring seal 34 may be deformed due to the pressure distribution in the rotor chamber 35. For example, as shown by the two-dot chain line in Figure 3, the ring seal 34 is deformed so that the center of the ring seal 34 protrudes toward the rotor unit 12.

[0091] The land portion 53 has a smaller radial width than the upstream portion 51 and the downstream portion 52. Furthermore, the vicinity of the land portion 53 has a relatively low rigidity due to the presence of the discharge port 47. For this reason, the ring seal 34 is significantly deformed in the vicinity of the land portion 53. This deformation brings the land portion 53 closer to the rotor unit 12, increasing the surface pressure on the seal surface 43a of the land portion 53. Region R1 of the seal surface 43a is closer to the rotor unit 12 than region R2, and the surface pressure is higher there than in region R2.

[0092] As described above, the seal surface 43a of the land portion 53 is provided with a plurality of grooves 70, which efficiently increases the oil film pressure. This allows the rotor unit 12 and the partition protrusion 43 to be kept spaced apart. The gear pump device 10 can suppress the occurrence of friction loss due to sliding between the rotor unit 12 and the partition protrusion 43, thereby improving efficiency.

[0093] The plurality of grooves 70 are provided in regions R1 and R3. Region R1 is closest to the rotor unit 12, but contact with the rotor unit 12 can be suppressed by the increase in oil film pressure caused by the plurality of grooves 70.

[0094] As described above, the inner gear 21 and the outer gear 22 rotate in the first circumferential direction Dc1. Conversely, in the gap G, the brake fluid rotates relative to the inner gear 21 and the outer gear 22 in the second circumferential direction Dc2.

[0095] Because a flow of brake fluid occurs in the second circumferential direction Dc2 and a flow of brake fluid in the low-pressure side direction Dl due to the pressure difference, a flow of brake fluid occurs in the gap G in the second reduction direction Dr2 relative to the inner gear 21 and the outer gear 22. That is, in the gap G, the brake fluid flows along the multiple grooves 80.

[0096] The brake fluid flows through the multiple grooves 80. Therefore, the brake fluid flowing through the straight portion 81 and the brake fluid flowing through the straight portion 82 collide with each other at the tip ends 80a of the grooves 80 in the second contraction direction Dr2. The collision of the brake fluids increases the oil film pressure in the gap G.

[0097] The plurality of grooves 80 are aligned in the second contraction direction Dr2 and overlap with each other in the second contraction direction Dr2. Therefore, the brake fluids collide with each other multiple times in the second contraction direction Dr2, causing a cumulative increase in oil film pressure.

[0098] The cross-sectional area of ​​the groove 80 decreases in the second decreasing direction Dr2, and the brake fluid flows in the second decreasing direction Dr2. As a result, the brake fluids collide strongly with each other at the tip 80a, and the oil film pressure increases efficiently.

[0099] The inner gear 21 and the outer gear 22 may be tilted relative to the first central axis Ax1 and the second central axis Ax2. The tilt of the inner gear 21 brings the external teeth 25 close to the partition convex portion 43, and the tilt of the outer gear 22 brings the internal teeth 27 close to the partition convex portion 43.

[0100] As described above, the plurality of grooves 80 are provided on the side surfaces 21 a of the external teeth 25 and the side surfaces 22 a of the internal teeth 27, thereby efficiently increasing the oil film pressure. This allows the rotor unit 12 and the partition protrusions 43 to be kept spaced apart from each other. The gear pump device 10 can suppress the occurrence of friction loss due to sliding between the rotor unit 12 and the partition protrusions 43, thereby improving efficiency.

[0101] The grooves 80 are farther away from the first central axis Ax1 than the grooves 70. Therefore, the external teeth 25 and the internal teeth 27 are longer in the circumferential direction than the land portions 53, and the number of grooves 80 can be greater than the number of grooves 70. Therefore, the grooves 80 can efficiently increase the oil film pressure. Furthermore, because the inner gear 21 and the outer gear 22 rotate, the positional accuracy of the grooves 80 in the circumferential direction may be low.

[0102] In the gear pump device 10 according to the first embodiment described above, at least one groove 70 is provided in the partitioning protrusion 43. The cross-sectional area of ​​the groove 70 decreases in the low-pressure side direction Dl or in a first reduction direction Dr1, which is a direction between the first circumferential direction Dc1 and the low-pressure side direction Dl. The groove 70 is spaced apart from the low-pressure region 35L and the high-pressure region 35H. When the inner gear 21 and the outer gear 22 rotate in the first circumferential direction Dc1, brake fluid flows in the first circumferential direction Dc1. Meanwhile, when brake fluid is transported from the low-pressure region 35L to the high-pressure region 35H, the pressure in the high-pressure region 35H increases, creating a pressure difference between the high-pressure region 35H and the low-pressure region 35L. Due to this pressure difference, brake fluid in the high-pressure region 35H also flows into the low-pressure region 35L through the gap G between the partitioning protrusion 43 and the rotor unit 12. That is, in the gap G, the brake fluid flows in the low-pressure side direction Dl or in a first contraction direction Dr1, which is a direction between the first circumferential direction Dc1 and the low-pressure side direction Dl. In the gap G, the brake fluid flows through the grooves 70 and converges in the first contraction direction Dr1. As the brake fluid collides with each other at the tips 70a of the grooves 70 in the first contraction direction Dr1, the oil film pressure (dynamic pressure) in the gap G increases, and the distance between the partition protrusion 43 and the rotor unit 12 is maintained. Because the brake fluid flows in the first contraction direction Dr1, the cross-sectional area of ​​the grooves 70 contracts toward the first contraction direction Dr1, and the grooves 70 do not communicate with either the low-pressure region 35L or the high-pressure region 35H, the oil film pressure in the gap G increases efficiently. As described above, the gear pump device 10 can prevent the partitioning protrusion 43 and the rotor unit 12 from coming into contact (sliding) with each other, and as a result, the efficiency of the gear pump device 10 can be improved.

[0103] A plurality of grooves 70 are provided in the partitioning protrusion 43. The plurality of grooves 70 are aligned in the first contraction direction Dr1. That is, increases in oil film pressure in the grooves 70 occur intermittently multiple times in the first contraction direction Dr1. Therefore, the gear pump device 10 can efficiently increase the oil film pressure over a wide range, and can prevent, for example, contact (sliding) between the rotor unit 12 and the partitioning protrusion 43 due to relative inclination.

[0104] Two adjacent grooves 70 overlap in the first contraction direction Dr1. That is, the leading end 70a of one groove 70 in the first contraction direction Dr1 and the leading end 70a of another groove 70 in the first contraction direction Dr1 are close to each other. Because the two positions where the oil film pressure increases are close to each other, the oil film pressure can increase cumulatively. Therefore, the gear pump device 10 can efficiently increase the oil film pressure in the gap G.

[0105] The partitioning protrusion 43 has a sealing surface 43a facing the rotor unit 12 and provided with a groove 70. The distance between the edge 43b of the sealing surface 43a in the low-pressure side direction Dl and the groove 70 is shorter than the distance between the edge 43c of the sealing surface 43a in the high-pressure side direction Dh opposite the low-pressure side direction Dl and the groove 70. For example, the wall 41 may be deformed due to the pressure distribution in the rotor chamber 35 and the rigidity of the wall 41. The wall 41 deforms so that the edge 43b of the sealing surface 43a in the low-pressure side direction Dl is closer to the rotor unit 12 than the edge 43c of the sealing surface 43a in the high-pressure side direction Dh. The groove 70 is biased and positioned near the edge 43b of the sealing surface 43a in the low-pressure side direction Dl. This allows the gear pump device 10 to efficiently prevent the edge 43b of the sealing surface 43a in the low-pressure side direction Dl and the rotor unit 12 from contacting (sliding) with each other.

[0106] At least one groove 80 is provided in at least one of the inner gear 21 and the outer gear 22. The cross-sectional area of ​​the groove 80 decreases in the low-pressure side direction Dl or in a second decreasing direction Dr2, which is a direction between the low-pressure side direction Dl and a second circumferential direction Dc2 opposite to the first circumferential direction Dc1. The groove 80 is spaced apart from at least one of the low-pressure region 35L and the high-pressure region 35H. As the inner gear 21 and the outer gear 22 rotate in the first circumferential direction Dc1, the brake fluid flows in the second circumferential direction Dc2 relative to the inner gear 21 and the outer gear 22. Meanwhile, due to the pressure difference, the brake fluid in the high-pressure region 35H also flows into the low-pressure region 35L through the gap G between the partition protrusion 43 and the rotor unit 12. That is, in the gap G, the brake fluid flows in the low-pressure side direction Dl or in a second contraction direction Dr2, which is a direction between the second circumferential direction Dc2 and the low-pressure side direction Dl, relative to the inner gear 21 and the outer gear 22. In the gap G, the brake fluid flows through the groove 80 and converges in the second contraction direction Dr2. The brake fluid collides with each other at the tips 80a of the grooves 80 in the second contraction direction Dr2, thereby increasing the oil film pressure in the gap G and maintaining the distance between the partition protrusion 43 and the rotor unit 12. Because the brake fluid flows in the second contraction direction Dr2, the cross-sectional area of ​​the groove 80 contracts toward the second contraction direction Dr2, and the groove 80 does not communicate with at least one of the low-pressure region 35L and the high-pressure region 35H, the oil film pressure in the gap G increases efficiently. As described above, the gear pump device 10 can prevent the partitioning protrusion 43 and the rotor unit 12 from coming into contact (sliding) with each other, and as a result, the efficiency of the gear pump device 10 can be improved.

[0107] (Second embodiment) The second embodiment will be described below with reference to Fig. 7. In the following description of the embodiments, components having the same functions as components already described are given the same reference numerals as the components already described, and further description may be omitted. Furthermore, components given the same reference numerals do not necessarily have all the same functions and properties, and may have different functions and properties according to each embodiment.

[0108] Fig. 7 is a cross-sectional view schematically showing a portion of a gear pump device 10 according to a second embodiment. As shown in Fig. 7, a groove 200 is provided in the inner gear 21 of the second embodiment instead of the groove 80. The groove 200 is substantially the same as the groove 80, except for the points described below. In addition, in the second embodiment, the groove 70 of the partitioning protrusion 43 and the groove 80 of the outer gear 22 are omitted.

[0109] The groove 200 is provided in an area 21d of the side surface 21a of the inner gear 21 that faces the land portion 53. Depending on the rotation of the inner gear 21, the area 21d may also face the upstream portion 51, the downstream portion 52, or the side surface 41a of the wall 41 of the low-pressure region 35L.

[0110] As described above, brake fluid flows in the second circumferential direction Dc2 and in the low-pressure side direction Dl due to the pressure difference, and thus, in the gap G, brake fluid flows in the second reduction direction Dr2 relative to the inner gear 21 and the outer gear 22. The brake fluid flows through the multiple grooves 200 and collides with each other at the tips of the grooves 200 (corresponding to the tips 80a of the grooves 80), increasing the oil film pressure in the gap G. As a result, the rotor unit 12 and the partition protrusion 43 can be kept spaced apart. The gear pump device 10 can suppress friction loss caused by sliding between the rotor unit 12 and the partition protrusion 43, thereby improving efficiency.

[0111] (Variation) Fig. 8 is a front view showing a portion of the ring seal 34 according to a first modified example. Fig. 9 is a front view showing a portion of the ring seal 34 according to a second modified example. Fig. 10 is a front view showing a portion of the ring seal 34 according to a third modified example. Fig. 11 is a front view showing a portion of the ring seal 34 according to a fourth modified example.

[0112] 8, 9, 10 and 11, the gear pump apparatus 10 may be provided with a plurality of grooves 300, 400, 500 and 600 instead of the grooves 70, 80 and 200. The grooves 300, 400, 500 and 600 are substantially identical to the grooves 70, 80 and 200, except as described below.

[0113] As shown in FIG. 8, each of the plurality of grooves 300 is formed in a substantially diamond shape (quadrangle, rectangle). As shown in FIG. 9, each of the plurality of grooves 400 has two semicircular portions 401, 402. Each of the two semicircular portions 401, 402 is formed in a substantially semicircular shape. The ends of the two semicircular portions 401, 402 in the first reduction direction Dr1 (or the second reduction direction Dr2) are connected to each other. As shown in FIG. 10, each of the plurality of grooves 500 is formed in a substantially triangular shape. As shown in FIG. 11, each of the plurality of grooves 600 is formed in a substantially semi-elliptical shape.

[0114] 8 to 11, the cross-sectional areas of the grooves 300, 400, 500, and 600 provided on the sealing surface 43a of the partitioning protrusion 43 decrease in a first reduction direction Dr1. When the grooves 300, 400, 500, and 600 are provided on at least one of the inner gear 21 and the outer gear 22, the cross-sectional areas of the grooves 300, 400, 500, and 600 decrease in a second reduction direction Dr2.

[0115] As described above, the multiple grooves 70, 80, 200, 300, 400, 500, and 600 can be formed in various shapes. The grooves may also be formed in other shapes. Furthermore, the grooves 70, 200, 300, 400, 500, and 600 are provided in the land portion 53, and the groove 80 is provided in the external teeth 25 of the inner gear 21 and the internal teeth 27 of the outer gear 22. However, the grooves may also be provided in other locations in the partitioning protrusion 43, the inner gear 21, and the outer gear 22.

[0116] The gear pump device according to at least one embodiment described above, for example, includes an inner gear rotatable about a rotation axis and an outer gear surrounding the inner gear, wherein a plurality of external teeth provided on the inner gear mesh with a plurality of internal teeth provided on the outer gear; a rotor chamber accommodating the rotor unit; an intake passage communicating with the rotor chamber; and a discharge passage communicating with the rotor chamber; and further includes a wall spaced from the rotor unit in an axial direction along the rotation axis, and a low-pressure region that protrudes from the wall toward the rotor unit and communicates with the discharge passage. The rotor unit includes a housing having a partitioning protrusion that partitions the rotor unit into a high-pressure region and a low-pressure region, and at least a portion of the low-pressure region is spaced from the high-pressure region in a low-pressure direction, which is either radially inward or radially outward, perpendicular to the rotation axis. When the inner gear rotates in a rotational direction around the rotation axis, the rotor unit transports fluid in a gap between the plurality of external teeth and the plurality of internal teeth from the low-pressure region to the high-pressure region. The partitioning protrusion has at least one groove whose cross-sectional area decreases in a reduction direction, which is either the low-pressure direction or a direction between the rotational direction and the low-pressure direction, and which is spaced apart from the low-pressure region and the high-pressure region. Thus, as an example, when the inner gear and the outer gear rotate in the rotational direction, the fluid flows in the rotational direction. Meanwhile, when the fluid is transported from the low-pressure region to the high-pressure region, the pressure in the high-pressure region increases, creating a pressure difference between the high-pressure region and the low-pressure region. Due to this pressure difference, the fluid in the high-pressure region also flows into the low-pressure region through a gap between the partitioning protrusion and the rotor unit. That is, in the gap, the fluid flows in a contraction direction, which is the low-pressure side direction or a direction between the rotation direction and the low-pressure side direction. In the gap, the fluid flows through the groove and converges in the contraction direction. When the fluids collide with each other at the ends of the groove in the contraction direction, the oil film pressure in the gap increases, and the distance between the partition convex portion and the rotor unit is maintained. Because the fluid flows in the contraction direction, the cross-sectional area of ​​the groove decreases in the contraction direction, and the groove does not communicate with either the low-pressure region or the high-pressure region, the oil film pressure in the gap increases efficiently.As a result, the gear pump device can prevent the partitioning protrusion and the rotor unit from coming into contact (sliding) with each other, thereby improving the efficiency of the gear pump device.

[0117] In the gear pump device, for example, the partition convex portion is provided with a plurality of the grooves, and the plurality of the grooves are aligned in the contraction direction. Therefore, for example, increases in oil film pressure in the grooves occur intermittently multiple times in the contraction direction. Therefore, the gear pump device can efficiently increase the oil film pressure over a wide range, and can suppress, for example, contact (sliding) between the rotor unit and the partition convex portion due to relative tilt.

[0118] In the above-described gear pump device, for example, two adjacent grooves among the plurality of grooves overlap in the contraction direction. Therefore, for example, an end of one groove in the contraction direction and an end of another groove in the contraction direction are close to each other. In other words, since two positions where the oil film pressure increases are close to each other, the oil film pressure can increase cumulatively. Therefore, the gear pump device can efficiently increase the oil film pressure in the gap.

[0119] In the above-described gear pump device, as an example, the partitioning protrusion has a seal surface facing the rotor unit and having the groove formed therein, and the distance between the edge of the seal surface and the groove in the low-pressure side direction is shorter than the distance between the edge of the seal surface and the groove in the high-pressure side direction opposite the low-pressure side direction. Therefore, as an example, the wall may be deformed due to, for example, the pressure distribution in the rotor chamber and the rigidity of the wall. The wall deforms so that the edge of the seal surface in the low-pressure side direction is closer to the rotor unit than the edge of the seal surface in the high-pressure side direction. The groove is biased and positioned near the edge of the seal surface in the low-pressure side direction. This allows the gear pump device to efficiently prevent the edge of the seal surface in the low-pressure side direction and the rotor unit from contacting (sliding) with each other.

[0120] The gear pump device according to at least one embodiment described above, as an example, includes an inner gear rotatable about a rotation axis and an outer gear surrounding the inner gear, and includes a rotor unit in which a plurality of external teeth provided on the inner gear mesh with a plurality of internal teeth provided on the outer gear, a rotor chamber accommodating the rotor unit, a suction passage communicating with the rotor chamber, and a discharge passage communicating with the rotor chamber, a wall spaced from the rotor unit in an axial direction along the rotation axis, and a partitioning protrusion protruding from the wall toward the rotor unit and partitioning the rotor chamber into a low-pressure region communicating with the suction passage and a high-pressure region communicating with the discharge passage, and and a housing, a portion of which is spaced from the high-pressure region in a low-pressure direction, which is either radially inward or radially outward, perpendicular to the rotation axis, wherein the rotor unit transports fluid in gaps between the plurality of external teeth and the plurality of internal teeth from the low-pressure region to the high-pressure region as the inner gear rotates in a first circumferential direction about the rotation axis, and at least one of the inner gear and the outer gear has a side surface facing the partition convex portion, and a cross-sectional area thereof decreases in a decreasing direction, which is either the low-pressure direction or a direction between a second circumferential direction opposite to the first circumferential direction and the low-pressure direction, and at least one groove is provided in the side surface, spaced from at least one of the low-pressure region and the high-pressure region. Thus, as an example, as the inner gear and the outer gear rotate in the first circumferential direction, fluid flows in a second circumferential direction relative to the inner gear and the outer gear. Meanwhile, as the fluid is transported from the low-pressure region to the high-pressure region, the pressure in the high-pressure region increases, creating a pressure difference between the high-pressure region and the low-pressure region. This pressure difference causes the fluid in the high-pressure region to also flow into the low-pressure region through the gap between the partition convex portion and the rotor unit. That is, in this gap, the fluid flows toward the low-pressure side or in a contraction direction, which is a direction between the second circumferential direction and the low-pressure side direction, relative to the inner gear and the outer gear. In this gap, the fluid flows through the groove and converges in the contraction direction. As the fluids collide with each other at the ends of the groove in the contraction direction, the oil film pressure in the gap increases, and the distance between the partition convex portion and the rotor unit is maintained.The fluid flows in the contraction direction, the cross-sectional area of ​​the groove contracts in the contraction direction, and the groove does not communicate with at least one of the low-pressure region and the high-pressure region, so the oil film pressure in the gap increases efficiently. As a result, the gear pump device can prevent the partition convex portion and the rotor unit from contacting (sliding against) each other, thereby improving the efficiency of the gear pump device.

[0121] While the embodiments of the present invention have been described above, the above-described embodiments and modifications are merely examples and are not intended to limit the scope of the invention. The above-described embodiments and modifications can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the configurations and shapes of each embodiment and each modification can be partially interchanged. [Explanation of symbols]

[0122] 10...gear pump device, 12...rotor unit, 14...housing, 21...inner gear, 21a...side surface, 22...outer gear, 22a...side surface, 25...external teeth, 27...internal teeth, 29...gap, 35...rotor chamber, 35L...low pressure region, 35H...high pressure region, 41...wall, 43...compartment convex portion, 43a...sealing surface, 43b, 43c...edge, 70, 80, 200, 300, 400, 500, 600...groove, Ax1...first central axis (rotation axis), Dc1...first circumferential direction (rotation direction), Dc2...second circumferential direction, Dr1...first reduction direction, Dr2...second reduction direction.

Claims

1. a rotor unit including an inner gear rotatable about a rotation axis and an outer gear surrounding the inner gear, wherein a plurality of external teeth provided on the inner gear mesh with a plurality of internal teeth provided on the outer gear; a housing provided with a rotor chamber that accommodates the rotor unit, an intake passage that communicates with the rotor chamber, and an exhaust passage that communicates with the rotor chamber, the housing having a wall that is spaced from the rotor unit in an axial direction along the rotation axis, and a partitioning protrusion that protrudes from the wall toward the rotor unit and partitions the rotor chamber into a low-pressure region that communicates with the intake passage and a high-pressure region that communicates with the exhaust passage, at least a portion of the low-pressure region being spaced from the high-pressure region in a low-pressure side direction that is either inward or outward in a radial direction perpendicular to the rotation axis; Equipped with the rotor unit transports fluid in gaps provided between the plurality of external teeth and the plurality of internal teeth from the low-pressure region to the high-pressure region as the inner gear rotates in a rotational direction around the rotation axis; The partitioning convex portion has at least one groove whose cross-sectional area decreases in a direction of decrease, which is the low-pressure side direction or a direction between the rotation direction and the low-pressure side direction, and which is spaced apart from the low-pressure region and the high-pressure region. Gear pump device.

2. A plurality of the grooves are provided in the partitioning convex portion, The plurality of grooves are aligned in the reduction direction.

2. The gear pump device of claim 1.

3. two adjacent grooves among the plurality of grooves overlap in the reduction direction; 3. The gear pump device according to claim 2.

4. the partitioning protrusion has a sealing surface facing the rotor unit and provided with the groove, a distance between an edge of the sealing surface and the groove in the low-pressure side direction is shorter than a distance between the edge of the sealing surface and the groove in a high-pressure side direction opposite to the low-pressure side direction; 4. The gear pump device according to claim 1.

5. a rotor unit including an inner gear rotatable about a rotation axis and an outer gear surrounding the inner gear, wherein a plurality of external teeth provided on the inner gear mesh with a plurality of internal teeth provided on the outer gear; a housing provided with a rotor chamber that accommodates the rotor unit, an intake passage that communicates with the rotor chamber, and an exhaust passage that communicates with the rotor chamber, the housing having a wall that is spaced from the rotor unit in an axial direction along the rotation axis, and a partitioning protrusion that protrudes from the wall toward the rotor unit and partitions the rotor chamber into a low-pressure region that communicates with the intake passage and a high-pressure region that communicates with the exhaust passage, at least a portion of the low-pressure region being spaced from the high-pressure region in a low-pressure side direction that is either inward or outward in a radial direction perpendicular to the rotation axis; Equipped with the rotor unit transports fluid in gaps provided between the plurality of external teeth and the plurality of internal teeth from the low-pressure region to the high-pressure region as the inner gear rotates in a first circumferential direction around the rotation axis, At least one of the inner gear and the outer gear has a side surface facing the partition convex portion, and a cross-sectional area thereof decreases in a decreasing direction, which is the low-pressure side direction or a direction between the low-pressure side direction and a second circumferential direction opposite to the first circumferential direction, and at least one groove spaced from at least one of the low-pressure region and the high-pressure region is provided on the side surface. Gear pump device.

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