Internal gear pump

Abstract

The internal gear pump (1) includes: a gear set (13) including a pinion (3) and a ring gear (4); a housing (10); a fixed crescent-shaped member (54); and an inlet passage (8) having an inlet (8a) communicating with the suction section (11) of the housing and an outlet (8b) connected to the movement trajectory (FL1) of the pinion tooth tip or the movement trajectory of the ring gear tooth tip between the suction section and the discharge section (12), and the inlet passage (8) causes the working oil flowing in from the inlet to flow out from the outlet to the tooth groove of the pinion or to the tooth groove of the ring gear.

Description

Technical Field

[0001] The technology disclosed here relates to an internal gear pump. Background Technology

[0002] Patent document 1 describes a conventional internal gear pump. This internal gear pump has a crescent-shaped component. The crescent-shaped component is located between the pinion and the ring gear. The outer teeth of the pinion and the inner teeth of the ring gear respectively abut against the crescent-shaped component. The crescent-shaped component of this internal gear pump is a fixed type, which neither moves towards the outer teeth nor towards the inner teeth.

[0003] The conventional internal gear pump also features a pressure transmission oil passage. This passage is formed in the ring gear side region, specifically in the region containing the crescent-shaped pinion and the ring gear side region, and connects the outlet to the space between the ring gear teeth. The pressure transmission oil passage directs a portion of the high-pressure working oil from the outlet to the space between the ring gear teeth, thus pre-pressurizing this space. Because the pressure difference between the outlet pressure and the pressure in the ring gear space is reduced, pressure fluctuations in this space when it opens to the outlet are suppressed. This conventional internal gear pump reduces noise caused by pressure fluctuations.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2023-183867 Summary of the Invention The problem that the invention aims to solve Internal gear pumps with a fixed crescent-shaped insert are used at relatively low speeds. This is because higher speeds cause cavitation at the pump's suction section. Cavitation occurs because the working oil pressure in the suction section decreases due to pressure loss. The maximum speed of internal gear pumps with a fixed crescent-shaped insert is limited to below the speed at which cavitation occurs. In conventional internal gear pumps, the maximum speed is also relatively low because cavitation occurs at relatively low speeds.

[0005] On the other hand, there is a need to increase the discharge flow rate of internal gear pumps. To increase the discharge flow rate without increasing the size of the internal gear pump, its rotational speed must be increased. However, as mentioned earlier, the maximum rotational speed of conventional internal gear pumps is relatively low.

[0006] The technology disclosed here aims to increase the maximum speed of internal gear pumps.

[0007] Solution for solving the problem The inventors of this application applied a structure that suppresses the decrease in suction pressure to an internal gear pump, thereby suppressing cavitation and increasing the rotational speed of the internal gear pump.

[0008] Specifically, the technology disclosed herein relates to an internal gear pump. This internal gear pump has the following features: A gear set, the gear set comprising a pinion with external teeth that is driven to rotate by a shaft and a ring gear with internal teeth that mesh with the external teeth; A housing having an intake and discharge portion for working oil, and housing the gear set in a manner that allows the gear set to rotate. A fixed crescent-shaped component, said fixed crescent-shaped component being located at the point of engagement and disengagement of the pinion and the ring gear; and The inlet path has an inlet communicating with the suction section and an outlet between the suction section and the discharge section that connects to the movement trajectory of the tooth tip of the pinion or the movement trajectory of the tooth tip of the ring gear. The inlet path allows working oil flowing in from the inlet to flow out from the outlet into the tooth groove of the pinion or the tooth groove of the ring gear.

[0009] In an internal gear pump, the rotation of the gear set gradually disengages the pinion and ring gear in the suction section. As the pinion and ring gear separate, working oil is drawn into the tooth grooves of the pinion and ring gear. It should be noted that the tooth groove is the clearance between the teeth of the gears. The drawn-in working oil is transported from the suction section to the discharge section as the gear set rotates. Then, in the discharge section, as the separated pinion and ring gear gradually approach and mesh again, the working oil in the tooth grooves of the pinion and ring gear is discharged through the discharge section.

[0010] The crescent-shaped component abuts against the tooth tips of the pinion and ring gear respectively between the suction and discharge sections. This crescent shape suppresses leakage flow and improves the efficiency of the internal gear pump.

[0011] Internal gear pumps have an inlet path. The inlet path includes an inlet and an outlet. The inlet communicates with the suction section. The outlet connects to the movement trajectory of the pinion tooth tip or the ring gear tooth tip between the suction and discharge sections. It should be noted that the movement trajectory of the gear tooth tip corresponds to the gear's addendum circle. The addendum circle is the circle connecting the tips of the teeth of the gear.

[0012] The outlet connects to the tooth grooves of the rotating pinion or ring gear. Working oil flows not only into the tooth grooves of the pinion or ring gear at the suction section, but also through the inlet passage. The inlet passage reduces the pressure loss of the internal gear pump. This low pressure loss suppresses the pressure drop of the working oil at the suction section, even as the speed of the internal gear pump increases. In other words, because the pressure of the working oil at the suction section can be maintained at a relatively high level even as the speed of the internal gear pump increases, cavitation is suppressed, thus allowing for an increase in the maximum speed of the internal gear pump.

[0013] Therefore, this type of internal gear pump can achieve a large discharge flow rate even with a small size by operating at high speed.

[0014] The inlet path can also be formed on the crescent-shaped component.

[0015] The inlet path formed in the crescent-shaped part allows the working oil to flow smoothly into the tooth groove of the pinion or the tooth groove of the ring gear.

[0016] Alternatively, the following approach can be adopted: the crescent-shaped component has a first arcuate wall that abuts against the outer teeth and a second arcuate wall that abuts against the inner teeth. The inlet path is formed by removing at least a portion of the arcuate wall of at least one of the first arcuate wall and the second arcuate wall.

[0017] In other words, the guide path is formed between the movement trajectory of the pinion tooth tip and the crescent-shaped component, or between the movement trajectory of the ring gear tooth tip and the crescent-shaped component. As part of the guide path, the crescent-shaped component suppresses the generation of eddies within the guide path and functions to rectify the flow of working oil through it. The guide path can suppress the pressure drop of the working oil at the suction section without reducing the efficiency of the internal gear pump.

[0018] Alternatively, the crescent-shaped component can extend from a first end that connects to the edge of the suction section to a second end on the discharge section side. The inlet path extends from the first end of the crescent-shaped member toward the outlet.

[0019] Because the inlet path extends from the first end of the crescent-shaped component, the working oil flows easily from the suction section into the inlet, resulting in low flow resistance in the inlet path. Since the low flow resistance of the inlet path helps to prevent pressure drop in the working oil at the suction section, the maximum speed of the internal gear pump can be further increased. Furthermore, the low flow resistance of the inlet path promotes the flow of working oil into the tooth grooves of the pinion or ring gear, thus increasing the discharge flow rate of the internal gear pump.

[0020] Alternatively, the extension range of the inlet path can be: extending from the first end to above the pitch of the gear that connects to the outlet, but not exceeding the midpoint between the first end and the second end of the crescent-shaped component.

[0021] If the inlet path extends too far towards the discharge section, leakage flow will increase, potentially reducing the efficiency of the internal gear pump. Conversely, if the inlet path is too short, its effect on reducing pressure loss will be minimal. As long as the inlet path extends from the suction section to the middle of the crescent-shaped part, pump efficiency can be maintained while reducing pressure loss. Furthermore, as long as the length of the inlet path is greater than the pitch of the gear (i.e., the distance between the gear teeth) connected to the outlet, the outlet will always be in communication with the gear tooth grooves, allowing working oil to flow out into the gear tooth grooves.

[0022] Alternatively, the housing can have a supporting surface that is orthogonal to the shaft, and this supporting surface supports the side of the gear set. The housing also has a second inlet passage, which includes a second inlet opening at the intake section and a second outlet opening on the support surface between the intake section and the discharge section, at least at a position corresponding to the position between the addendum circle and the dedendum circle of the pinion, or at a position corresponding to the position between the addendum circle and the dedendum circle of the ring gear. The second inlet passage allows working oil flowing in from the second inlet to flow out from the second outlet into the tooth groove of the pinion or into the tooth groove of the ring gear. It should be noted that the dedendum circle is the circle at the root of each tooth of the gear.

[0023] The second inlet path, like the first inlet path, allows the working oil to flow into the tooth grooves of the pinion or the ring gear. The internal gear pump equipped with both the first and second inlet paths further increases its maximum speed due to lower pressure loss.

[0024] Alternatively, the housing may have a first support surface and a second support surface, with the first support surface supporting a first side surface of the gear set, and the second support surface being the surface opposite to the first support surface, supporting a second side surface of the gear set. The second guide path is formed on at least one of the first support surface and the second support surface.

[0025] Whether the second inlet path is formed on the first support surface or the second support surface, it can suppress the pressure drop of the working oil at the suction section.

[0026] Invention Effects Because the inlet path of the aforementioned internal gear pump suppresses the pressure drop of the working oil at the suction section, its maximum speed can be increased. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of an internal gear pump.

[0028] Figure 2 This is an exploded view of an internal gear pump.

[0029] Figure 3 The import path is shown.

[0030] Figure 4 It is a slanted view of the imported road.

[0031] Figure 5 The import path is shown according to a variant example.

[0032] Figure 6 The import path is shown according to a variant example.

[0033] Figure 7 The import path is shown according to a variant example.

[0034] Figure 8 The import path is shown according to a variant example.

[0035] Figure 9 The import path is shown according to a variant example.

[0036] Figure 10 It is a perspective view of the first and second inlet paths. Detailed Implementation

[0037] The following description, with reference to the accompanying drawings, illustrates an embodiment of an internal gear pump. The internal gear pump described herein is an example.

[0038] (Overall structure of an internal gear pump) Figure 1 or Figure 2 An example of an internal gear pump 1 is provided. It should be noted that... Figure 2 This is an exploded view after the front cover 6 of the internal gear pump 1 has been removed from the gear housing 5. The gear housing 5 and the front cover 6 together constitute the housing 10 of the internal gear pump 1.

[0039] The internal gear pump 1 includes a shaft 2. The shaft 2 is along... Figure 1 Extending horizontally along the middle of the paper. The front end of axis 2, that is... Figure 1 The left end of the shaft extends from the housing 10. The front end of the shaft 2 is connected to a prime mover (not shown in the figure). The prime mover is, for example, an electric motor.

[0040] The internal gear pump 1 includes a pinion 3. The pinion 3 is integrally formed with the shaft 2 at the middle position. The pinion 3 is coaxial with the shaft 2. The pinion 3 rotates together with the shaft 2. The pinion 3 has external teeth 31.

[0041] The internal gear pump 1 includes a ring gear 4. The ring gear 4 meshes with a pinion 3. The ring gear 4 is eccentric relative to the shaft 2. Figure 2 C1 is the rotation axis of the pinion 3, and C2 is the rotation axis of the ring gear 4. Internal teeth 41 are formed on the inner circumferential surface of the ring gear 4. Figure 2 In the right figure, in the area on the left side of the paper, a portion of the external teeth 31 of the pinion 3 meshes with a portion of the internal teeth 41 of the ring gear 4.

[0042] The pinion 3 and the ring gear 4 together form the gear set 13 of the internal meshing gear pump 1.

[0043] The gear housing 5 houses the pinion 3 and the ring gear 4. An inner hole 53 is formed on the gear housing 5. The base end of the shaft 2, i.e. Figure 1 The right end is located in the inner hole 53.

[0044] The pinion 3 and the ring gear 4 are rotatably housed within the gear housing 5. The gear housing 5 has a sliding surface 51 for sliding the outer peripheral surface 42 of the ring gear 4. The outer peripheral surface 42 of the ring gear 4 has a circular cross-section. The sliding surface 51 of the gear housing 5 also has a circular cross-section. The sliding surface 51 is eccentric relative to the shaft 2.

[0045] The gear housing 5 has a first support surface 52 orthogonal to the sliding surface 51. The first support surface 52 is a surface orthogonal to the shaft 2. The sliding surface 51 and the first support surface 52 form a space 50 for accommodating the pinion 3 and the ring gear 4. This space 50 is... Figure 1 The left side of the paper is open. The first side surface 32 of the pinion 3 and the first side surface 43 of the ring gear 4 are respectively supported on the first support surface 52 of the gear housing 5, and slide along the first support surface 52. It should be noted that the first side surface 32 of the pinion 3 is a surface orthogonal to the rotation axis C1 of the pinion 3. Figure 1 The right-hand side of the paper. The first side 43 of the ring gear 4 is a surface orthogonal to the rotation axis C2 of the ring gear 4. Figure 1 The right side of the paper.

[0046] The front cover 6 is disposed adjacent to the gear housing 5. The front cover 6 and the gear housing 5 are fixed together to form a single unit. The front cover 6 is connected to the gear housing 5 and has a second support surface 61 that encloses the space 50. The second side surface 33 of the pinion 3 and the second side surface 44 of the ring gear 4 are respectively supported on the second support surface 61 of the front cover 6 and slide along the second support surface 61. It should be noted that the second side surface 33 of the pinion 3 is a surface orthogonal to the rotation axis C1 of the pinion 3. Figure 1 The left-hand side of the paper. The second side 44 of the ring gear 4 is a surface orthogonal to the rotation axis C2 of the ring gear 4. Figure 1 The left side of the paper.

[0047] A support hole 62 is formed through the front end cover 6 for the shaft 2 to pass through. The shaft 2 is rotatably supported on the front end cover 6 and the gear housing 5 by a bearing 63 and a bearing member 64. The opening of the support hole 62 is sealed by a sealing member 621.

[0048] The front cover 6 and gear housing 5 have a suction section 11. Working oil is drawn from the suction section 11 into the internal space 50 of the housing 10. Figure 1 As shown, the inlet of the suction section 11 opens on the outer peripheral surface of the front cover 6. (As indicated...) Figure 1 and Figure 2 As shown, the outlets of the intake section 11 open on the second support surface 61 of the front end cover 6 and the first support surface 52 of the gear housing 5, respectively. The outlets of the intake section 11 also extend circumferentially along the rotation direction of the shaft 2.

[0049] The front cover 6 and gear housing 5 also have a discharge section 12. Working oil is discharged from the internal space 50 of the housing 10 through the discharge section 12. Figure 1 As shown, the outlet of the discharge section 12 opens on the outer peripheral surface of the gear housing 5. Furthermore, the orientation of the inlet of the suction section 11 and the orientation of the outlet of the discharge section 12 can be as follows: Figure 1 The directions shown are different, but they can also be the same.

[0050] The inlets of the discharge section 12 open on the second support surface 61 of the front cover 6 and the first support surface 52 of the gear housing 5, respectively. For example... Figure 2 As shown, the inlet of the discharge section 12 is also on the opposite side of the suction section 11 across the shaft 2, and extends circumferentially along the rotation direction of the shaft 2.

[0051] A crescent-shaped component 54 is provided in the gear housing 5. The crescent-shaped component 54 is disposed at the meshing and disengagement point of the pinion 3 and the ring gear 4. The crescent-shaped component 54 suppresses leakage flow from the discharge section 12 to the intake section 11.

[0052] The crescent-shaped component 54 extends circumferentially within a specified angle range along the rotation direction of axis 2. For example... Figure 2 As shown, the crescent-shaped component 54 has an arc shape or a crescent shape when viewed along the axial direction of shaft 2. The first end 543 of the crescent-shaped component 54 is connected to the edge of the intake portion 11, and the second end 544 is connected to the edge of the discharge portion 12. The crescent-shaped component 54 also has two arc-shaped walls, namely a first arc-shaped wall 541 and a second arc-shaped wall 542. The first arc-shaped wall 541 and the second arc-shaped wall 542 are respectively connected to the first end 543 and the second end 544. The first arc-shaped wall 541 and the second arc-shaped wall 542 are respectively erected on the first support surface 52 of the gear housing 5.

[0053] The tip of the outer tooth 31 of the pinion 3 abuts against the first arcuate wall 541 of the crescent-shaped member 54. The tip of the inner tooth 41 of the ring gear 4 abuts against the second arcuate wall 542 of the crescent-shaped member 54. Both the first arcuate wall 541 and the second arcuate wall 542 are fixed walls that do not move toward the outer tooth 31 or the inner tooth 41.

[0054] The following is a brief description of the operation of the internal gear pump 1. When the prime mover drives the shaft 2 according to... Figure 2 When rotated counterclockwise as shown in the middle right figure, the pinion 3 and the ring gear 4 will rotate from the intake section 11 through the crescent-shaped part 54 to the discharge section 12.

[0055] At the suction section 11 inside the housing 10, as the external teeth 31 of the meshing pinion 3 separate from the internal teeth 41 of the ring gear 4, working oil is drawn from the suction section 11 into the space between the external teeth 31 and the internal teeth 41. The drawn-in working oil is transported from the suction section 11 to the discharge section 12 via the crescent-shaped member 54 as the pinion 3 and the ring gear 4 rotate.

[0056] At the discharge section 12 inside the housing 10, the outer teeth 31 of the separated pinion 3 gradually approach and mesh with the inner teeth 41 of the ring gear 4. As a result, working oil is discharged from between the outer teeth 31 and the inner teeth 41 through the discharge section 12.

[0057] The crescent-shaped component 54, by abutting against the tooth tips of the pinion 3 and the ring gear 4 respectively between the suction section 11 and the discharge section 12, suppresses leakage flow within the space 50. The crescent-shaped component 54 improves the efficiency of the internal gear pump 1.

[0058] (Structure to increase the maximum speed of an internal gear pump) The internal gear pump 1 includes an inlet passage 8. The inlet passage 8 reduces the pressure loss of the internal gear pump 1, suppressing pressure drop at the suction section 11 during operation. Because pressure drop at the suction section 11 is suppressed, the rotational speed of the internal gear pump 1 can be increased without cavitation. In other words, the inlet passage 8 can increase the maximum rotational speed of the internal gear pump 1.

[0059] like Figure 2 or Figure 3 As shown, the guide path 8 is formed on the crescent-shaped member 54. More specifically, the guide path 8 is formed on the first arcuate wall 541 of the crescent-shaped member 54.

[0060] like Figure 4 As shown in the shaded area, the inlet path 8 is formed by cutting away a portion of the first arcuate wall 541. More specifically, the inlet path 8 includes an inlet 8a and an outlet 8b. Figure 3 or Figure 4 As shown by the double-dotted line, the inlet 8a is located at the first end 543 of the crescent-shaped member 54 and communicates with the suction section 11. Figure 3 or Figure 4 As shown by the double-dotted line, the outlet 8b extends from the edge of the outlet of the suction section 11, along the movement trajectory FL1 of the pinion 3's tooth tip, towards the discharge section 12. During operation, the outlet 8b of the internal gear pump 1 contacts the tooth groove of the rotating pinion 3. Working oil flowing from the inlet 8a into the guide path 8 flows out from the outlet 8b into the tooth groove of the pinion 3. The working oil flows not only into the tooth grooves of the pinion 3 and the ring gear 4 in the suction section 11, but also into the tooth groove of the pinion 3 through the guide path 8. The guide path 8 reduces the pressure loss of the internal gear pump 1.

[0061] Because the inlet path 8 reduces the pressure loss of the internal gear pump 1, the pressure drop of the working oil at the suction section 11 is suppressed even when the rotational speed of the internal gear pump 1 increases. In other words, cavitation is suppressed even when the rotational speed of the internal gear pump 1 increases. In the internal gear pump 1, the rotational speed at which cavitation occurs increases. As a result, the maximum rotational speed of the internal gear pump 1 increases. By operating at high speed, the internal gear pump 1 can increase the discharge flow rate even with its small size.

[0062] Furthermore, since the guide passage 8 is formed by removing a portion of the first arcuate wall 541 of the crescent-shaped member 54, the guide passage 8 is formed between the movement trajectory FL1 of the pinion 3's tooth tip and the crescent-shaped member 54. The radial width of the guide passage 8 gradually narrows as it moves away from the inlet 8a. The guide passage 8 allows the working oil to flow smoothly into the tooth groove of the pinion 3. In addition, due to the division by the crescent-shaped member 54, the radial width of the guide passage 8 is relatively narrow. At the formation of the guide passage 8, the crescent-shaped member 54 suppresses the generation of eddies within the guide passage 8 and performs the function of rectifying the flow of working oil through the guide passage 8. The guide passage 8 can suppress the pressure drop in the suction section 11 without reducing the efficiency of the internal gear pump 1.

[0063] Furthermore, the inlet passage 8 extends from the first end 543 of the crescent-shaped member 54 toward the discharge portion 12, and the outlet 8b also extends relatively long from the first end 543 of the crescent-shaped member 54 toward the discharge portion 12. The inlet passage 8 has low flow resistance. The low flow resistance of the inlet passage 8 further suppresses the pressure drop of the working oil at the suction portion 11. The circumferentially extended inlet passage 8 makes it possible to further increase the maximum speed of the internal gear pump 1. In addition, the low flow resistance of the inlet passage 8 promotes the inflow of working oil from the suction portion 11 to the tooth groove of the pinion 3. This is beneficial for increasing the discharge flow rate of the internal gear pump 1.

[0064] Here, the shape of import path 8 is explained in further detail. For example... Figure 3 As shown, regarding the circumferential length (or angle θ) of the inlet path 8, the following approach can be adopted: the extension range of the inlet path 8 extends from the suction section 11 to above the pitch P of the pinion 3 that connects to the outlet 8b, but does not exceed the midpoint M between the first end 543 and the second end 544 of the crescent-shaped member 54. It should be noted that the circumferential length is expressed here using the angle θ centered on the rotation axis C1.

[0065] This is because if the inlet path 8 extends too far towards the discharge section 12, leakage flow within the space 50 will increase, potentially reducing the efficiency of the internal gear pump 1. Furthermore, if the circumferential length of the inlet path 8 is too short, the amount of working oil introduced through it will decrease, resulting in an insignificant effect on reducing flow resistance at the suction section 11. As long as the inlet path 8 extends within the range of the midpoint M from the suction section 11 to the crescent-shaped member 54, both maintaining the efficiency of the internal gear pump 1 and reducing flow resistance can be achieved. Additionally, as long as the length of the inlet path 8 is above the pitch of the gear connected to the outlet 8b, the outlet 8b will always be connected to the gear tooth groove, allowing working oil to flow out into the gear tooth groove.

[0066] The shape of the guide path 8, formed by cutting off a portion of the crescent-shaped member 54, is not limited to, for example... Figure 3 The smooth curved surface shape shown can also be a planar shape that appears as a straight line when viewed along the extension direction of axis 2. Alternatively, the shape of the guide path 8 can also be a shape formed by connecting multiple curved surfaces or planes circumferentially.

[0067] In addition, such as Figure 5 As shown, the first end 543 of the crescent-shaped part 54 can also be formed with a smooth curved surface. The flow resistance of the inlet path 8 will be reduced.

[0068] The guide path 8 can also be formed in a portion of the height direction of the crescent-shaped member 54. The height direction of the crescent-shaped member 54, as referred to here, means the direction in which the crescent-shaped member 54, which is erected vertically from the first support surface 52 of the gear housing 5, moves away from the first support surface 52. For example, as... Figure 6 As shown in (a), in the height direction of the crescent-shaped member 54, the guide path 81 may be formed in contact with the second support surface 61, rather than on the side of the first support surface 52. Furthermore, in the height direction of the crescent-shaped member 54, the guide path may be formed in contact with the first support surface 52, rather than on the side of the second support surface 61. Further, the guide path may be formed at the center of the crescent-shaped member 54 in the height direction, rather than being formed in contact with both the first support surface 52 and the second support surface 61.

[0069] in addition, Figure 6 As shown in (b), multiple guide paths 82 arranged in the height direction of the crescent-shaped member 54 can also be formed on the crescent-shaped member 54.

[0070] The guide path is not limited to being formed on one side of the first arcuate wall 541 of the crescent-shaped member 54. For example, as... Figure 7 As shown, by cutting away the first arcuate wall 541 and the second arcuate wall 542 of the crescent-shaped member 54, the internal gear pump 1 can also have an inner guide passage 83 on the side of the pinion 3 that clamps the crescent-shaped member 54, and an outer guide passage 84 on the side of the ring gear 4 that clamps the crescent-shaped member 54. The inlet 83a of the inner guide passage 83 is located at the first end 543, and the outlet 83b extends towards the discharge section 12 along the movement trajectory FL1 of the tooth tip of the pinion 3. The inlet 84a of the outer guide passage 84 is located at the first end 543, and the outlet 84b extends towards the discharge section 12 along the movement trajectory FL2 of the tooth tip of the ring gear 4. In addition, the structure or shape of the inner guide passage 83 and the structure or shape of the outer guide passage 84 can adopt the various structures or shapes described above.

[0071] Alternatively, the internal gear pump 1 may omit the inner guide path on the side of the pinion 3 that clamps the crescent-shaped part 54, and only have the outer guide path on the side of the ring gear 4 that clamps the crescent-shaped part 54.

[0072] Furthermore, the guide path is not limited to being formed by cutting off the first arcuate wall 541 or the second arcuate wall 542 of the crescent-shaped member 54. For example, as Figure 8 As shown in (a), an inlet path 85 may also be formed inside the crescent-shaped member 54. Specifically, the inlet 85a of the inlet path 85 opens at the first end 543 of the crescent-shaped member 54. The inlet path 85 extends from the first end 543 toward the discharge portion 12 inside the crescent-shaped member 54. Then, the inlet path 85 connects to the outlet 85b, which opens in the first arcuate wall 541 of the crescent-shaped member 54. The outlet 85b is in contact with the movement trajectory of the tooth tip of the pinion 3 due to the opening in the first arcuate wall 541. The inlet path 85 allows the working oil flowing in from the inlet 85a to flow from the outlet 85b into the tooth groove of the pinion 3.

[0073] Alternatively, the outlet of the inlet path 85 may open on the second arcuate wall 542 instead of the first arcuate wall 541. Furthermore, the outlet of the inlet path 85 may also open on both the first arcuate wall 541 and the second arcuate wall 542.

[0074] The crescent-shaped component 54 can also be formed from multiple components. For example, such as Figure 8 As shown in (b), the crescent-shaped member 54 can also be formed by a first crescent-shaped member 545 and a second crescent-shaped member 546. The number of components forming the crescent-shaped member 54 is not limited to two, but can also be three or more.

[0075] The first crescent-shaped member 545 is positioned close to the suction section 11, and the second crescent-shaped member 546 is positioned away from the suction section 11. Figure 8 In example (b), the guide path 86 is formed by the first crescent-shaped member 545. The sidewall 861 of the first crescent-shaped member 545 is located radially outward from the movement trajectory FL1 of the pinion 3 tooth tip. The guide path 86 extends from the intake portion 11 to the discharge portion 12 between the sidewall 861 and the pinion 3. Furthermore, the structure or shape of the guide path formed by the first crescent-shaped member 545 can adopt the various structures or shapes described above.

[0076] Alternatively, the first crescent-shaped member 545 may also form an inlet path between itself and the ring gear 4, or between itself and the pinion 3, and between itself and the ring gear 4.

[0077] Alternatively, the first crescent-shaped member 545 may not be part of the crescent-shaped member 54, but rather a guide path member used to form the guide path 86. In this case, the first end of the crescent-shaped member is the first end 543 of the crescent-shaped member 546. The first end 543 of the crescent-shaped member 546 is located away from the edge of the outlet of the suction section 11.

[0078] Multiple components forming a crescent shape, such as Figure 8 As shown in (b), they can be connected to each other or separated from each other. For example, as Figure 9 As shown in (a), the first crescent-shaped member 545 and the second crescent-shaped member 546 are separate from each other.

[0079] Alternatively, the inlet path can also be formed by multiple components that form a crescent shape. Figure 9 In (a), the guide path 87 extends across the side wall 861 of the first crescent-shaped member 545 and the first arcuate wall 541 of the second crescent-shaped member 546, respectively.

[0080] like Figure 9As shown in (b), a portion of the guide path 88 may also be formed inside the first crescent-shaped member 545. Specifically, the inlet 88a of the guide path 881 opens at the first end 547 of the first crescent-shaped member 545. The guide path 881 extends through the interior of the first crescent-shaped member 545 from the first end 547 toward the discharge portion 12. Then, the guide path 881 connects to the outlet 88b, which opens at the second end 548 of the first crescent-shaped member 545. Since the second end 548 of the first crescent-shaped member 545 and the first end 543 of the second crescent-shaped member 546 are separate from each other, the outlet 88b communicates with the guide path 882 formed by the first arcuate wall 541 of the second crescent-shaped member 546. The guide path 882 is in contact with the movement trajectory of the tooth tip of the pinion 3. The guide path 88, formed by the guide path 881 and the guide path 882, allows the working oil flowing in from the inlet 88a to flow into the tooth groove of the pinion 3.

[0081] Figure 10 This indicates an internal gear pump 1 equipped with a first inlet path 8 and a second inlet path 9 as inlet paths. The first inlet path 8 and... Figure 4 The guide path 8 shown is the same. The second guide path 9 is formed in the gear housing 5.

[0082] The second inlet channel 9 is located radially inside the crescent-shaped member 54, abutting the first arcuate wall 541 of the crescent-shaped member 54, and extending circumferentially along the first arcuate wall 541. The second inlet channel 9 has the shape of a groove recessed from the first support surface 52. The second inlet channel 9 includes an inlet 9a and an outlet 9b. The inlet 9a opens into the suction section 11. The outlet 9b opens into the first support surface 52. The outlet 9b extends from the edge of the outlet of the suction section 11 toward the discharge section 12 at the first support surface 52.

[0083] The outlet 9b of the second inlet path 9 is located on the first side 32 of the pinion 3 and is connected to the tooth groove of the pinion 3. When the internal gear pump 1 is running, the working oil flows into the second inlet path 9 from the inlet 9a and flows out from the outlet 9b into the tooth groove of the pinion 3.

[0084] The working oil can flow into the tooth grooves of the pinion 3 and the ring gear 4 through the first inlet passage 8 and the second inlet passage 9. The first inlet passage 8 and the second inlet passage 9 can reduce the pressure loss of the internal gear pump 1, thereby helping to increase the maximum speed of the internal gear pump 1.

[0085] Alternatively, the second guide path 9 can also be formed adjacent to the second arcuate wall 542 on the radially outer side of the crescent-shaped member 54. Alternatively, the second guide path 9 can also be formed on both the radially inner and outer sides of the crescent-shaped member 54.

[0086] Alternatively, the second guide path 9 may be formed on either the first support surface 52 or the second support surface 61. The second guide path 9 may also be formed on both the first support surface 52 and the second support surface 61.

[0087] Symbol Explanation 1. Internal gear pump; 10. Shell; 13. Gear set; 2. Axis; 3. Small gear; 31, external teeth; 32, (of the small gear) the first lateral surface; 33, (of the pinion) the second lateral surface; 4. Ring gear; 41, internal teeth; 43, (of the ring gear) the first lateral surface; 44. (The second lateral surface of the ring gear); 52, First support surface; 54. Crescent-shaped component; 541, First circular arc wall; 542, Second circular arc wall; 543, First End; 544, the second end; 545, First crescent-shaped component; 546, Second crescent-shaped component; 547, First End; 548, the second end; 61, Second support surface; 8. Import path; 8a, Inlet; 8b, Outlet; 81, Import path; 82, Pathway; 83, inner guide path; 83a, inlet; 83b, Outlet; 84, outer access path; 84a, inlet; 84b, Outlet; 85, Pathway; 85a, inlet; 85b, Outlet; 86, Pathway; 87, Import path; 88, import path; 88a, inlet; 88b, Outlet; 881, import path; 882, import path; 9. Second inlet path; 9a, Inlet; 9b, Outlet; FL1, the movement trajectory of the tip of the pinion; FL2, the movement trajectory of the tooth tip of the ring gear.

Claims

1. An internal gear pump, the internal gear pump comprising: A gear set, the gear set comprising a pinion with external teeth that is driven to rotate by a shaft and a ring gear with internal teeth that mesh with the external teeth; A housing having an intake and discharge portion for working oil, and housing the gear set in a manner that allows the gear set to rotate. A fixed crescent-shaped component is located at the point where the pinion and the ring gear mesh and separate. as well as The inlet path has an inlet communicating with the suction section and an outlet between the suction section and the discharge section that connects to the movement trajectory of the tooth tip of the pinion or the movement trajectory of the tooth tip of the ring gear. The inlet path allows working oil flowing in from the inlet to flow out from the outlet into the tooth groove of the pinion or the tooth groove of the ring gear.

2. The internal gear pump according to claim 1, wherein, The inlet path is formed on the crescent-shaped member.

3. The internal gear pump according to claim 2, wherein, The crescent-shaped component has a first arcuate wall that abuts against the outer teeth and a second arcuate wall that abuts against the inner teeth. The inlet path is formed by removing at least a portion of the arcuate wall of at least one of the first arcuate wall and the second arcuate wall.

4. The internal gear pump according to claim 2 or 3, wherein, The crescent-shaped member extends from a first end that connects with the edge of the suction section to a second end on the discharge section side. The inlet path extends from the first end of the crescent-shaped member toward the outlet.

5. The internal gear pump according to claim 4, wherein, The extension range of the inlet path is: extending from the first end to above the pitch of the gear that connects to the outlet, but not exceeding the midpoint between the first end and the second end of the crescent-shaped component.

6. The internal gear pump according to any one of claims 1 to 5, wherein, The housing has a support surface, which is orthogonal to the shaft, and the support surface supports the side of the gear set. The housing also has a second inlet path, which includes a second inlet opening at the intake section and a second outlet opening on the support surface between the intake section and the discharge section, at least at a position corresponding to the position between the addendum circle and the dedendum circle of the pinion, or at a position corresponding to the position between the addendum circle and the dedendum circle of the ring gear. The second inlet path allows working oil flowing in from the second inlet to flow out from the second outlet into the tooth groove of the pinion or into the tooth groove of the ring gear.

7. The internal gear pump according to claim 6, wherein, The housing has a first support surface and a second support surface, which serve as the support surface. The first support surface supports a first side surface of the gear set, and the second support surface is the surface opposite to the first support surface, supporting a second side surface of the gear set. The second guide path is formed on at least one of the first support surface and the second support surface.

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