Internal gear pump

Abstract

The utility model discloses make the inner gear pump miniaturization. The inner gear pump has the shell, forms on the cover portion of shell, has the spout - suck transfer interval, suck - spout transfer interval and multiple insert through -hole, and the cover portion is divided into multiple imaginary regions through the first imaginary line of the midpoint of spout - suck transfer interval and the center of drive shaft and the second imaginary line of the center of drive shaft perpendicularly through drive shaft relative to first imaginary line and drive shaft, and the insert through -hole is formed respectively in the spout - suck area of spout - suck transfer interval side compared with the second imaginary line and the suck - spout area of suck - spout transfer interval side compared with the second imaginary line, and at least one of the insert through -hole of spout - suck area is formed in the position of being closer to drive shaft compared with the insert through -hole of suck - spout area.

Description

Technical Field

[0001] This utility model relates to an internal gear pump. Background Technology

[0002] Japanese Patent Application Publication No. JP2022-150294A discloses a cycloidal gear pump comprising a motor section and a pump section. The motor section has a drive shaft supported by a motor housing for free rotation, and the drive shaft is rotated to drive the pump section. The pump section rotates due to the driving force of the drive shaft, drawing in and ejecting fluid. The motor housing, which houses the motor section and the pump section, is covered by a pump cover. The pump cover is fixed to the pump body of the motor housing by being threaded with multiple bolts. The multiple bolts are arranged on the same circle. Utility Model Content

[0003] The internal gear pump described in Japanese Patent Application Publication No. JP2022-150294A is mounted to the mounted body in a contact manner. Therefore, the smaller the internal gear pump, the better its installability to the mounted body. From the viewpoint of installability, miniaturization of the internal gear pump is desirable.

[0004] The purpose of this invention is to miniaturize the internal gear pump.

[0005] According to one aspect of the present invention, an internal gear pump comprises: a pump section that rotates via a drive shaft to eject liquid; and a housing that houses the pump section. The pump section has: an inner rotor having a plurality of external teeth and connected to the drive shaft; and an outer rotor having a plurality of internal teeth meshing with the external teeth and disposed outside the inner rotor. The housing comprises: a body section that houses the pump section; and a cover section mounted on the body section and covering the pump section. The cover section has a suction port, an ejection port, an ejection-suction transfer section, a suction-ejection transfer section, and a plurality of through holes. The suction port guides liquid to the pump section, the ejection port guides liquid ejected from the pump section, and the ejection-suction transfer section is located between the top end of the ejection port and the rear end of the suction port in the rotational direction of the drive shaft. The transfer interval is located between the top end of the suction port and the rear end of the ejection port in the rotation direction of the drive shaft. The plurality of through holes are used for fastening components to be inserted to fix the cover to the body. The cover is divided into a plurality of imaginary regions by a first imaginary line passing through the midpoint of the ejection-suction transfer interval and the center of the drive shaft, and a second imaginary line passing perpendicularly to the first imaginary line and the center of the drive shaft. The through holes are respectively formed in the ejection-suction region on the side of the ejection-suction transfer interval compared with the second imaginary line, and in the suction-ejection region on the side of the suction-ejection transfer interval compared with the second imaginary line. At least one of the through holes formed in the ejection-suction region is formed at a position closer to the drive shaft than the through hole formed in the suction-ejection region.

[0006] Preferably, at least two of the through holes formed in the ejection-inhalation region and the through holes formed in the inhalation-ejection region are formed on a line parallel to the second imaginary line.

[0007] Preferably, at least two insertion holes are formed in both the ejection-inhalation region and the inhalation-ejection region, and the distance between the two insertion holes in the ejection-inhalation region that are closer to the ejection-inhalation transfer interval is less than the distance between the two insertion holes in the inhalation-ejection region that are closer to the inhalation-ejection transfer interval.

[0008] Preferably, the shortest distance between the insertion hole and the adjacent suction port or ejection port is formed to be the same.

[0009] Preferably, the plurality of through holes are formed on the same circle centered on the outer rotor, and the outer periphery of the suction port and the outer periphery of the ejection port are formed on the same circle centered on the outer rotor and different from the same circle on which the plurality of through holes are formed. Attached Figure Description

[0010] Figure 1 This is a perspective view of the internal gear pump involved in the embodiment of this utility model. Figure 2 This is a top view of the pump section of an internal gear pump according to an embodiment of the present invention. Figure 3 This is a top view of the pump section of the internal gear pump according to an embodiment of the present invention, showing the state with the cover removed. Figure 4 This is a top view showing the back of the cover. Detailed Implementation

[0011] Hereinafter, with reference to the accompanying drawings, an internal gear pump 100 according to an embodiment of the present invention will be described. The internal gear pump 100 is, for example, mounted in a vehicle and sprays coolant (liquid) for cooling an electric motor mounted in the vehicle, or oil (liquid) for lubricating gears mounted in the vehicle. The internal gear pump 100 can also be used as a fluid pressure supply source for spraying working fluid (liquid) for driving equipment. Furthermore, the internal gear pump 100 can also be mounted in industrial machinery other than vehicles.

[0012] Figure 1 This is a 3D view of the internal gear pump 100. Figure 2 , Figure 3 This is a top view of the pump section 10 of the internal gear pump 100. Figure 3 The diagram shows the state after the cover 40, described later, has been removed. Additionally, Figure 2 , Figure 3 From Figure 1 A top view of the pump section 10 as seen from the lower side. (See image below.) Figure 2 , Figure 3 As shown, the internal gear pump 100 includes: a pump section 10, which is driven by a drive shaft 1 (see reference 1). Figure 3 The pump unit 10 is rotated to spray liquid; the motor unit 15 drives the pump unit 10 by rotating the drive shaft 1; the control unit 17 controls the motor unit 15; and the housing 20 houses the pump unit 10, the motor unit 15, and the control unit 17. Additionally, Figure 3 , Figure 4 The arrow indicates the direction of rotation of drive shaft 1.

[0013] like Figure 3As shown, the pump unit 10 has an inner rotor 11 connected to the drive shaft 1 and an outer rotor 12 disposed outside the inner rotor 11. The inner rotor 11 and the outer rotor 12 are housed in the housing 20 (specifically, the body 30 described later), and are arranged eccentrically to each other and covered by the cover 40 of the housing 20. Specifically, the inner rotor 11 is arranged with its center aligned with the center of the drive shaft 1, and the outer rotor 12 is arranged with its center extending from the drive shaft 1 towards... Figure 2 , Figure 3 The lower side is offset. The inner rotor 11 has multiple external teeth 11a on its outer circumferential surface, and the outer rotor 12 has multiple internal teeth 12a on its inner circumferential surface that slide in contact with the external teeth 11a. The external teeth 11a and internal teeth 12a are formed in a manner with different numbers of teeth, and the pump chamber 13 is divided by the adjacent external teeth 11a of the inner rotor 11 and the internal teeth 12a of the outer rotor 12. Multiple pump chambers 13 are formed in the pump chamber 10.

[0014] Figure 4 This is a top view showing the rear side of the cover 40 that covers the pump section 10. (See attached image.) Figure 2 , Figure 4 As shown, a suction port 42 for guiding liquid from the outside to the pump section 13 is formed on the cover 40 (see reference). Figure 4 ) and suction port 43, and discharge port 44 that guides the liquid ejected from pump chamber 13 to the outside (see reference) Figure 4 The inner rotor 11 and outer rotor 12 rotate when the drive shaft 1 is rotated by the motor 15. The outer teeth 11a of the inner rotor 11 slide into contact with the inner teeth 12a of the outer rotor 12. As the inner rotor 11 and outer rotor 12 rotate, the volume of the pump chamber 13 repeatedly expands and contracts. In the expansion region (suction region) of the expanding pump chamber 13, liquid is drawn in through the suction port 42 and suction inlet 43. In the contraction region (ejection region) of the contracting pump chamber 13, liquid is ejected and guided to the outside through the ejection port 44 and ejection outlet 45. The detailed structure of the cover 40 will be described later.

[0015] like Figure 2 , Figure 3 As shown, the housing 20 includes: a body portion 30, which houses the pump portion 10, the motor portion 15, and the control portion 17; and a cover portion 40 (see reference 1). Figure 2 It is mounted on the body part 30 and covers the pump part 10. The body part 30 and the cover part 40 are arranged in a manner that is axially aligned with the drive shaft 1 (hereinafter also referred to as "axial").

[0016] like Figure 3As shown, the body portion 30 has an insertion hole (not shown) for inserting the drive shaft 1 and a pump receiving recess 31 for receiving the pump portion 10. The pump receiving recess 31 is a recessed portion with a concave bottom, which internally receives the inner rotor 11 and the outer rotor 12 of the pump portion 10 in an eccentric manner. Specifically, the center of the pump receiving recess 31 coincides with the center of the outer rotor 12 and is formed offset from the center of the drive shaft 1. A plurality of fastening members 50 for mounting the cover portion 40 are formed on the end face 30a of the body portion 30 (see reference). Figure 2 The fastening hole 32 is for fastening. The fastening component 50 is a bolt. The fastening hole 32 is formed in a manner corresponding to the insertion hole 47 of the cover 40, which will be described later.

[0017] like Figure 2 As shown, the cover portion 40 is provided to cover the pump receiving recess 31 that houses the inner rotor 11 and the outer rotor 12. The cover portion 40 is mounted to the end face 30a of the body portion 30 by a fastening member 50. The cover portion 40 has: a disc-shaped cover body portion 41, which is mounted to the end face 30a; and a cylindrical protrusion 48, which is formed to protrude axially from the cover body portion 41.

[0018] The cover body portion 41 is formed such that it protrudes axially from the region opposite to the inner rotor 11 and the outer rotor 12. For example... Figure 2 , Figure 4 As shown, the aforementioned suction port 42 is formed on the cover body portion 41 (see reference). Figure 4 ), Ejection port 44 (refer to) Figure 4 ), and intake port 43, and shaft receiving portion 46 for receiving the top end of drive shaft 1 (see reference) Figure 4 The cover 40 is fixed to the body 30 by inserting the fastening member 50 through a plurality of through holes 47. Additionally, the aforementioned nozzle 45 is formed in the protrusion 48 (see reference). Figure 2 ).

[0019] like Figure 4As shown, the suction port 42 and the ejection port 44 are formed on an arc on the back side of the cover body portion 41. The suction port 42 is formed in the suction region, and the ejection port 44 is formed in the ejection region. The inner peripheries 42a and 44a of the suction port 42 and the ejection port 44 are formed on a circle A1 centered on the drive shaft 1, and the outer peripheries 42b and 44b are formed on a circle B1 centered on the outer rotor 12. An ejection-suction transfer zone 60 is formed between the top end portion 44a of the ejection port 44 and the rear end portion 42d of the suction port 42 in the rotation direction of the drive shaft 1, and an suction-ejection transfer zone 61 is formed between the top end portion 42c of the suction port 42 and the rear end portion 44d of the ejection port 44 in the rotation direction of the drive shaft 1. The cover body 41 is divided into multiple imaginary regions by a first imaginary line 62 passing through the midpoint of the ejection-intake transfer zone 60 and the center of the drive shaft 1, and a second imaginary line 63 passing perpendicularly to the first imaginary line 62 and the center of the drive shaft 1. Specifically, an ejection-intake region 65 is formed on the side closer to the ejection-intake transfer zone 60 than on the second imaginary line 63, and an intake-ejection region 66 is formed on the side closer to the intake-ejection transfer zone 61 than on the second imaginary line 63. The intake port 42 and the ejection port 44 are formed in a line-symmetrical manner with respect to the first imaginary line 62.

[0020] The suction port 43 is formed on an arc on the surface of the cover body 41 and communicates with the suction port 42. The suction port 43 is formed so as to face the suction port 42 as a whole (see reference). Figure 4 ).like Figure 4 As shown, a shaft receiving portion 46 is concavely formed at the center of the back side of the cover body portion 41, and the top end of the drive shaft 1 is housed inside, supporting the drive shaft 1 to rotate freely. The nozzle 45 is formed such that it passes through the protrusion 48 in the axial direction and communicates with the discharge port 44. In the internal gear pump 100, the protrusion 48 is inserted into a hole (not shown) provided in the device for mounting the internal gear pump 100, and the suction port 43 and the nozzle 45 are respectively connected to the flow path (not shown).

[0021] like Figure 4As shown, multiple through holes 47 are formed in the ejection-intake region 65 and the intake-ejection region 66, respectively. Furthermore, the through holes 47a formed in the ejection-intake region 65 and the through holes 47b formed in the intake-ejection region 66 are formed on different circles centered on the center of the drive shaft 1. Specifically, two through holes 47 are formed on the same circle in the ejection-intake region 65 (circle A2 centered on the axis of the drive shaft 1) and two on the same circle in the intake-ejection region 66 (circle A3 centered on the axis of the drive shaft 1). The through holes 47a formed in the ejection-intake region 65 are positioned closer to the drive shaft 1 than the through holes 47b formed in the intake-ejection region 66. In other words, the diameter of circle A2 formed for the through holes 47a is smaller than the diameter of circle A3 formed for the through holes 47b. Furthermore, through holes 47a and 47b are formed on lines 63a and 63b that are parallel to the second imaginary line 63, respectively.

[0022] Thus, in the internal gear pump 100, the through-hole 47a formed in the ejection-suction region 65 is positioned closer to the drive shaft 1 than the through-hole 47b formed in the suction-ejection region 66. Therefore, compared to the case where all the through-holes 47 are formed on the same circle, the outer diameter of the ejection-suction region 65 can be reduced, thereby reducing the size of the ejection-suction region 65 in the cover portion 40. This allows for miniaturization of the internal gear pump 100.

[0023] Furthermore, in the internal gear pump 100, the pressure in the pump chamber 13 is higher in the ejection-suction transfer zone 60 compared to the suction-ejection transfer zone 61. Therefore, a greater force acts on the ejection-suction transfer zone 60 side of the cover portion 40. However, since the through-hole 47a on the ejection-suction transfer zone 60 side is formed closer to the drive shaft 1, the shortest distance D1 between the through-hole 47a and the adjacent suction port 42 or ejection port 44 is smaller compared to the case where all through-holes 47 are formed on the same circle. Therefore, the internal gear pump 100 is miniaturized while deformation of the cover portion 40 is suppressed.

[0024] Furthermore, two through holes 47 are formed in both the ejection-suction region 65 and the suction-ejection region 66. The distance D2 between the through holes 47a formed in the ejection-suction region 65 is smaller than the distance D3 between the through holes 47b formed in the suction-ejection region 66. Therefore, when a relatively large pressure acts on the ejection-suction region 65 of the cover 40 from the pump chamber 13 as described above, the smaller distance D2 between the through holes 47a suppresses deformation of the cover 40.

[0025] Furthermore, the shortest distance D1 between the through-hole 47 and the adjacent intake port 42 or ejection port 44 is formed to be the same. In other words, since all through-holes 47 are formed on a circle B2 centered on the outer rotor 12, the shortest distance D1 between them and the outer periphery 42b of the intake port 42 or the outer periphery 44b of the ejection port 44, which are formed on the same circle B1 centered on the outer rotor 12, is the same (see reference). Figure 4 The diameter of circle B2 is larger than the diameter of circle B1. This prevents the cover 40 from deforming locally due to pressure within the pump chamber 13, thus allowing the cover 40 to deform uniformly. Therefore, it prevents communication between the ejection and suction sides of the pump section 10, or leakage of liquid from the pump section 10 between the cover 40 and the main body 30. This improves the performance of the internal gear pump 100.

[0026] According to the above implementation method, the following effects are achieved.

[0027] In the internal gear pump 100, the through hole 47a formed in the ejection-suction region 65 is formed at a position closer to the drive shaft 1 than the through hole 47b formed in the suction-ejection region 66. Therefore, the ejection-suction region 65 in the cover 40 can be reduced, thereby enabling the internal gear pump 100 to be miniaturized.

[0028] Next, variations of this embodiment will be described. The following variations are also within the scope of this invention, and it is possible to combine the structures shown in the variations with the structures described in the above embodiments, or to combine the structures described in the following different variations with each other.

[0029] <Modified Example> In the above embodiment, two through holes 47 are formed on the same circle (circle A2) of the ejection-intake region 65 and on the same circle (circle A3) of the intake-ejection region 66, respectively. The distance D2 between the through holes 47a in the ejection-intake region 65 is less than the distance D3 between the through holes 47b formed in the intake-ejection region 66. Furthermore, the shortest distance D1 between the through hole 47 and the adjacent intake port 42 or ejection port 44 is formed to be the same. However, the above structure is not mandatory.

[0030] For example, one of the multiple through holes 47a in the ejection-intake region 65 may be formed at a position closer to the drive shaft 1 than the through hole 47b in the intake-ejection region 66. Specifically, one of the through holes 47a in the ejection-intake region 65 may be formed on circle A2, while the other through holes 47a in the ejection-intake region 65 and the through holes 47b in the intake-ejection region 66 may be formed on circle A3, which has a larger diameter than circle A2. Alternatively, two through holes 47 may be formed (one in the ejection-intake region 65 and one in the intake-ejection region 66), or more than five through holes 47 may be formed. Alternatively, through holes 47 may be formed in the ejection-inhalation region 65 and the intake-ejection region 66, respectively, and at least one of the through holes 47a formed in the ejection-inhalation region 65 may be formed at a position closer to the drive shaft 1 than the through hole 47b formed in the intake-ejection region 66.

[0031] Furthermore, in order to suppress deformation of the cover 40, when a relatively high pressure is exerted from the liquid in the pump section 10 on the ejection-suction region 65, at least two through holes 47 need to be formed in both the ejection-suction region 65 and the suction-ejection region 66. Moreover, it is acceptable if at least two of the through holes 47a formed in the ejection-suction region 65 and the through holes 47b formed in the suction-ejection region 66 are formed on lines parallel to the second imaginary line 63 (63a, 63b), and the distance D2 between the two through holes 47a closest to the ejection-suction transfer section 60 is less than the distance D3 between the two through holes 47b closest to the suction-ejection transfer section 61.

[0032] The structure, function, and effects of the embodiments of this utility model are summarized and explained below.

[0033] The internal gear pump 100 includes: a pump section 10 that rotates via a drive shaft 1 to eject liquid; and a housing 20 that houses the pump section 10. The pump section 10 has: an inner rotor 11 having a plurality of external teeth 11a and connected to the drive shaft 1; and an outer rotor 12 having a plurality of internal teeth 12a that mesh with the external teeth 11a and disposed outside the inner rotor 11. The housing 20 has: a body section 30 that houses the pump section 10; and a cover section 40 that is mounted on the body section 30. The cover 40 covers the pump section 10 and has a suction port 42, a discharge port 44, a discharge-suction transfer section 60, a suction-discharge transfer section 61, and a plurality of through holes 47. The suction port 42 guides liquid to the pump section 10, and the discharge port 44 guides liquid sprayed from the pump section 10. The discharge-suction transfer section 60 is located between the top end 44c of the discharge port 44 and the rear end 42d of the suction port 42 in the rotation direction of the drive shaft 1. The inhalation-ejection transfer zone 61 is located between the top end 42c of the inhalation port 42 and the rear end 44d of the ejection port 44 in the rotation direction of the drive shaft 1. The plurality of through holes are used for fastening members 50 to be inserted to fix the cover 40 to the body 30. The cover 40 is divided into a plurality of imaginary regions by a first imaginary line 62 passing through the midpoint of the ejection-inhalation transfer zone 60 and the center of the drive shaft 1, and a second imaginary line 63 passing perpendicularly to the first imaginary line 62 and the center of the drive shaft 1. Through holes 47 are respectively formed in the ejection-inhalation region 65 on the side of the ejection-inhalation transfer zone 60 compared with the second imaginary line 63, and in the inhalation-ejection region 66 on the side of the inhalation-ejection transfer zone 61 compared with the second imaginary line 63. At least one of the through holes 47a formed in the ejection-inhalation region 65 is formed at a position closer to the drive shaft 1 than the through hole 47b formed in the inhalation-ejection region 66.

[0034] In this structure, at least one of the through holes 47a formed in the ejection-suction region 65 is located closer to the drive shaft 1 than the through holes 47b formed in the suction-ejection region 66. Therefore, compared to the case where multiple through holes 47 are formed on the same circle, the ejection-suction region 65 in the cover portion 40 can be reduced. As a result, the internal gear pump 100 can be miniaturized.

[0035] Furthermore, in the internal gear pump 100, at least two insertion holes 47a formed in the ejection-suction region 65 and at least two insertion holes 47b formed in the suction-ejection region 66 are formed on lines 63a and 63b that are parallel to the second imaginary line 63.

[0036] Furthermore, in the internal gear pump 100, at least two through holes 47 are formed in both the ejection-suction region 65 and the suction-ejection region 66. The distance D2 between the two through holes 47a that are closer to the ejection-suction transfer interval 60 in the ejection-suction region 65 is less than the distance D3 between the two through holes 47b that are closer to the suction-ejection transfer interval 61 in the suction-ejection region 66.

[0037] In this structure, when a large pressure is exerted from the liquid in the pump chamber 10 on the ejection-suction region 65 of the cover 40, the distance D2 between the through holes 47a is small, thus suppressing the deformation of the cover 40.

[0038] Furthermore, in the internal gear pump 100, the shortest distance D1 between the through hole 47 and the adjacent suction port 42 or discharge port 44 is formed to be the same.

[0039] In addition, in the internal gear pump 100, a plurality of through holes 74 are formed on the same circle (B2) centered on the outer rotor 12, and the outer periphery 42b of the suction port 42 and the outer periphery 44b of the discharge port 44 are formed on the same circle (B1) centered on the outer rotor 12 and different from the same circle on which the plurality of through holes 74 are formed.

[0040] In the above structure, the cover 40 is prevented from being locally deformed due to the pressure of the liquid inside the pump section 10, and the liquid inside the pump section 10 is prevented from leaking out.

[0041] The embodiments of the present invention have been described above. However, the above embodiments are only a part of the application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific structure of the above embodiments.

[0042] This application claims priority based on Japanese Patent Application 2023-51951 filed with the Japan Patent Office on March 28, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. An internal gear pump, characterized in that, have: The pump unit sprays out liquid by rotating a drive shaft; A housing that encloses the pump unit. The pump unit has: An inner rotor having multiple external teeth and connected to the drive shaft; An outer rotor having a plurality of internal teeth that mesh with the external teeth, and being disposed outside the inner rotor. The outer casing has: The main body houses the pump unit; A cover portion, which is installed on the body portion and covers the pump portion, The cover portion has an intake port, an exhaust port, an exhaust-intake transfer zone, an intake-exhaust transfer zone, and multiple through holes. The suction port directs liquid to the pump unit. The ejection port guides the liquid ejected from the pump section. The ejection-inhalation transfer zone is located between the top end of the ejection port and the rear end of the inhalation port in the rotational direction of the drive shaft. The inhalation-ejaculation transfer zone is located between the top end of the inhalation port and the rear end of the ejaculation port in the rotational direction of the drive shaft. The plurality of through holes are used for fastening components to be inserted to fix the cover to the body. The cover is divided into multiple imaginary regions by a first imaginary line passing through the midpoint of the ejection-inhalation transfer zone and the center of the drive shaft, and a second imaginary line passing perpendicularly to the first imaginary line and the center of the drive shaft. The insertion holes are respectively formed in the ejection-inhalation region on the side of the ejection-inhalation transfer interval compared to the second imaginary line, and in the inhalation-ejection region on the side of the inhalation-ejection transfer interval compared to the second imaginary line. At least one of the through holes formed in the ejection-intake region is formed at a position closer to the drive shaft than the through holes formed in the intake-ejection region. The shortest distance between the insertion hole and the adjacent suction port or ejection port is respectively formed to be the same.

2. The internal gear pump as described in claim 1, characterized in that, The insertion hole formed in the ejection-inhalation region and the insertion hole formed in the inhalation-ejection region are each formed in at least two on a line parallel to the second imaginary line.

3. The internal gear pump as described in claim 1, characterized in that, At least two insertion holes are formed in both the ejection-inhalation region and the inhalation-ejection region. The distance between two through holes that are closer to the ejection-inhalation transfer zone in the through holes formed in the ejection-inhalation region is less than the distance between two through holes that are closer to the inhalation-ejection transfer zone in the through holes formed in the inhalation-ejection region.

4. The internal gear pump as described in claim 1, characterized in that, The plurality of through holes are formed on the same circle centered on the outer rotor. The outer periphery of the inhalation port and the outer periphery of the ejection port are formed on the same circle centered on the outer rotor and different from the same circle on which the plurality of through holes are formed.

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