Pump

Abstract

Liquid pump (1), comprising: a pump housing (10) defining a pump chamber (19); an electric motor (20) having a shaft (26) and being attached to the pump housing (10); a drive gear (30) fixed to the shaft (26) and received in the pump chamber (19), the drive gear (30) having a central body (31) and a plurality of vanes (32) extending radially outward from the central body (31); an inlet (12) in fluid communication with the pump chamber (19); and an outlet (13) in fluid communication with the pump chamber (19), the outlet (13) having a first end (13a) adjacent to the pump chamber (19) and a second end (13b) remote from the pump chamber (19), wherein a cross section S1 of the first end (13a) is smaller than a cross section S2 of the second end (13b), wherein the first end (13a) and the second end (13b) of the outlet (13) are separated by a distance L, wherein 0.035 ≤ (s 2 π − s 1 π ) / L ≤ 0.07 is.

Description

FIELD OF THE INVENTION

[0001] The invention relates to a pump and in particular to a pump for liquids. BACKGROUND OF THE INVENTION

[0002] Fluid pumps are found in many different machines and applications. In many vehicles, fluid pumps are used to spray water or a cleaning solution onto the vehicle's windshield or headlights.

[0003] Common pumps used in such applications typically have a pump casing with a circular cross-section and a liquid discharge pipe extending tangentially to the casing. While the discharge pipe may deliver a sufficient amount of liquid, the liquid pressure may be too low. Furthermore, many common liquid pumps, when operating at peak efficiency, discharge more liquid than necessary, which is why most of these common liquid pumps are not operating at peak efficiency.

[0004] US 5 180 280 A1 discloses a centrifugal pump with a cylindrical housing and a diffuser. JP H11 247 798 A and DE 29 17 029 A1 each disclose a centrifugal pump with a spiral-shaped pump chamber. DE 21 14 178 A relates to a fluid machine with a pump and a diffuser, wherein a diffuser axis is arranged tangentially to a circle described by the pump. US 2013 / 0 177 451 A1 discloses a pump for a windshield washer system. Furthermore, US 2004 / 0 179 949 A1 discloses a centrifugal pump unit for a multi-stage pump arrangement. OVERVIEW

[0005] The invention aims to create a more efficient liquid pump.

[0006] According to the invention, this is achieved by forming a diffuser in the outlet from the pump chamber.

[0007] According to one aspect of the present invention, a liquid pump is provided, comprising: a pump housing defining a pump chamber; a motor having a motor shaft and fixed to the pump housing; a drive gear fixed to the shaft and disposed within the pump chamber, the drive gear having a central body and a plurality of vanes extending radially outward from the central body; an inlet in fluid communication with the pump chamber; and an outlet in fluid communication with the pump chamber, the outlet having a first end adjacent to the pump chamber and a second end remote from the pump chamber, a cross-section of the first end S1 being smaller than a cross-section of the second end S2. The first end and the second end of the outlet are separated by a distance L, wherein 0.035≤(s2π−s1π)L≤0.07 is.

[0008] Preferably, the radially outer ends of the vanes of the drive wheel define a circle of diameter D1, and a radially outer surface of one vane of the plurality of vanes has an axial height of b, the cross-section S1 of the first end of the outlet being defined by Y×(πD1), where 0.01≤Y≤0.02.

[0009] Preferably, the radially outer ends of the vanes of the drive wheel define a circle of diameter D1, and the pump chamber has a substantially circular cross-section of diameter DV; where 1.04 ≤ D v / D1 ≤ 1.1.

[0010] Preferably, the plurality of vanes are evenly distributed circumferentially around the central body of the drive wheel.

[0011] Preferably the drive wheel has three blades.

[0012] Preferably, a circumferential width of a wing of the plurality of wings increases with the extension of the wing away from the central body.

[0013] Preferably, one of the plurality of wings has a rectangular cross-section.

[0014] Optionally, one of the plurality of wings has a T-shaped cross-section.

[0015] Preferably, an end cap is sealingly secured to an inner surface of the pump housing, the pump chamber being defined by an axial surface of the pump housing and the end cap, the motor being disposed in the pump housing and separated from the pump chamber by the end cap, and the shaft extending through the end cap for engagement with the drive gear in the pump chamber.

[0016] Preferably, the pump has an annular seal, and a groove is formed in a radially outer surface of the end cap to receive the annular seal, and the annular seal forms a sealed connection with the inner surface of the pump housing.

[0017] Preferably, the end cap has a sealing hole plate with a through opening through which the hub extends, wherein a sealing ring is arranged in the sealing hole plate and forms a seal between the end cap and the shaft.

[0018] Preferably, the sealing ring has an outer portion in contact with the sealing hole plate and an inner portion in contact with the shaft, the inner portion having a curved surface such that a first end and a second end of the inner portion are in contact with the shaft and a central portion of the inner portion is spaced from the shaft.

[0019] Preferably, the pump chamber has two outlets arranged such that the direction of rotation of the drive wheel determines through which outlet liquid is pumped.

[0020] Preferably, the inlet extends in a direction substantially parallel to an axial direction of the shaft.

[0021] Preferably, a portion of the central body of the drive wheel is received in the inlet.

[0022] Preferably the motor is a DC motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] A preferred embodiment of the invention will now be described by way of example with reference to the figures of the accompanying drawings. Identical structures, elements, or parts that appear in more than one figure are identified identically in all of those figures. The dimensions and features shown in the figures have been chosen for convenience of illustration and are not necessarily to scale. The figures are listed below. Fig. 1 shows a liquid pump according to a preferred embodiment of the present invention; Fig. 2 is a sectional view of the pump of Fig. 1; Fig. 3 is another sectional view of the pump of Fig. 1; Fig. 4 shows a pump in Fig. 1 end cap used; Fig. 5A, Fig. 5B and Fig. 5C are respectively a perspective view, top view and side view of a pump in the Fig. 1 drive wheel used; Fig. 6A and Fig. 6B are respectively a perspective view and a side view of an alternative drive wheel; Fig. 7 is a sectional view of a seal used in the pump; Fig. 8 is a perspective view of a liquid pump according to a second embodiment; and Fig. 9 is a perspective view of a liquid pump according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Fig. 1 shows a liquid pump 1 according to the preferred embodiment of the present invention. Fig. 2 is a sectional view of the pump 1 along the section plane (II), and Fig. Figure 3 is a sectional view of the pump 1 along the section plane (III). For ease of explanation, the terms "vertical" or "vertical direction" refer to a direction substantially parallel to an axial direction of the pump 1, while the terms "horizontal" or "horizontal direction" refer to a direction substantially perpendicular to the axial direction. In practice, the pump 1 can, of course, be oriented in a variety of directions.

[0025] The pump 1 has a pump housing 10, an end cap 14 mounted on the housing, a motor 20 fixed in the housing, and a drive wheel 30 configured for rotation with the motor 20. The pump housing 10 and the end cap 14 define a substantially cylindrical pumping chamber 19 in which the drive wheel 30 is arranged. An inlet 12 is located on an axial end wall 11 of the pump housing 10 and extends away from the housing substantially parallel to an axial direction of the pump. In other embodiments, the inlet 12 may extend in other directions. For example, as shown in Fig. As shown in Figure 8, the inlet 12 may extend in a direction substantially perpendicular to an axial direction of the pump. The axial direction of the pump is substantially the same as the axial direction of the motor 20.

[0026] In addition, one or more outlets 13 are located on a side wall of the pump housing 10 near the axial end wall 11 and extend outwardly in a direction substantially tangential to a circumference of the pump 1. In the preferred embodiment, the pump 1 has two outlets 13, each outlet 13 corresponding to a different fluid flow path. In other embodiments, as in Fig. 9, the pump may have only a single outlet 13.

[0027] The outlet 13 has a first end 13a connected to the pump chamber 19 and a second end 13b remote from the pump chamber. The first end 13a and the second end 13b may hereinafter be referred to as the outlet inlet 13a and the outlet outlet 13b, respectively. The cross-section of the outlet inlet 13a and the outlet outlet 13b (e.g., the cross-section substantially perpendicular to a direction of liquid flow in the outlet 13) may be defined as S1 and S2, respectively. To form the diffuser, S2 is larger than S1 (i.e., S2 > S1). In the preferred embodiment, the cross-section of the outlet 13 gradually increases from S1 to S2 along the direction of liquid flow.

[0028] Fig. Figure 4 shows the end cap 14 used in the preferred embodiments. On one side, facing the drive wheel, the end cap 14 has a substantially planar end face 15. A side wall 16 extends from a radially outer edge of the end face 15 in an axial direction and forms a radially outer surface of the end cap. A seal aperture plate 17 is formed by a central through-opening and extends axially and inwardly from the end face 15. The side wall 16 has a groove 18 extending circumferentially around the side wall 16. The groove 18 receives an annular seal 5 which forms a sealed connection with an inner surface of the pump housing 10 when the end cap is attached to the pump housing. Preferably, the annular seal 5 is a rubber O-ring. Thus, the end cap 14 defines one end of the pump chamber 19, i.e.the pump chamber 19 is formed in the pump housing 10 between the axial end wall 11 and the end cap 14.

[0029] The sealing hole plate 17 of the end cap 14 receives a sealing ring 6 through which the shaft 26 of the motor 20 extends for connection to the drive wheel. As the shaft 26 rotates during operation, it remains in contact with the sealing ring 6, preventing fluid contained in the chamber 19 from reaching the motor 20. Fig. As shown in Figure 7, the sealing ring 6 preferably comprises an outer ring 7, an inner ring 9, and a connecting ring 8 interposed between the outer ring 7 and the inner ring 9, connecting the rings together. Preferably, the inner ring 9 is curved or partially spherical (i.e., the axial ends of the inner ring 9 bulge or slope inward from a central portion of the inner ring 9) so that the axial ends of the inner ring 9 are in contact with the shaft 26, while a space is formed between a central portion of the inner ring 9 and the shaft 26. The seal thus forms two sealing connections with the shaft, and the space therebetween can be used for a lubricant to lubricate the sealing connections.

[0030] The motor 20 is attached to the pump housing 10 on a side of the end cap 14 remote from the chamber 19. The motor 20 may be a direct current (DC) motor having a stator 20a, an end plate 20b, and a rotor 20c. The stator 20a includes a motor housing 24 and a plurality of permanent magnets 25 received within the housing 24 (i.e., mounted to an inner surface of the housing 24). Furthermore, the housing 24 may form a bearing retainer located at an axial end of the housing. The stator 20a further has a bearing 23 mounted in the bearing retainer. The end plate 20b is mounted at an open end of the housing 24 and closes the open end. The end plate 20b supports a plurality of electric brushes 21 and a second bearing 22. The rotor 20c has a shaft 26, a commutator 27, and a rotor core 28 fixed to the shaft 26.A plurality of winding coils 29 are wound around the rotor core 28 and connected to the commutator 27, which is arranged to be in sliding contact with the brushes 21. The shaft 26 is journaled in the bearings 22, 23 so that the rotor 20c can rotate with respect to the stator 20a. During operation, electric current flows through the brushes 21 to the commutator 27, energizing the winding coils 28 and causing the rotor 20c to rotate within the stator 20a.

[0031] The motor 20 described above is a brushed DC motor. However, other motor types, such as a brushless DC motor, an alternating current (AC) motor, or other mechanical device capable of generating rotary motion, may of course be used in other embodiments.

[0032] The Fig. 5A-5D show the preferred drive wheel 30 used in the pump of Fig. 1. The drive wheel 30 has a body 31 extending in an axial direction and a plurality of vanes 32 extending radially from the body 31. The drive wheel 30 is disposed in the chamber 19 and mounted on the shaft 26 of the motor 20 such that it rotates with the shaft 26. Optionally, a portion of the body 31 is received in the inlet 12. In the illustrated embodiment, the drive wheel 30 has three vanes 32 evenly distributed circumferentially around the body 31. In other embodiments, the drive wheel 30 may, of course, have any number of vanes 32.

[0033] As shown, the vanes 32 have a square or rectangular cross-section, with the circumferential width gradually increasing as the vane 32 extends away from the body 31. A radially outer surface of the vanes 32 has a height b in the axial direction. As the drive gear 30 rotates, the vanes 32 define a circle of diameter D1.

[0034] During operation of the pump 1, the drive wheel 30 rotates with the shaft 26. Liquid flows through the inlet 12 into the chamber 19 and is driven by the rotating drive wheel 30 to the outlet inlet 13a, where the liquid leaves the pump housing 10 through the outlet outlet 13b. Due to the increasing cross-section between the outlet inlet 13a and the outlet outlet 13b, the outlet 13 forms a diffuser as the liquid flows from the outlet inlet 13a to the outlet outlet 13b. In the diffuser, the kinetic energy of the liquid flowing therein is converted into pressure, thereby increasing the pressure of the liquid flow. In embodiments with two outlets 13, such as in the preferred embodiment of the Fig. 1-3, the direction of rotation of the drive wheel 30 can be used to select the outlet 13 through which the liquid is pumped.

[0035] The side surfaces of the vanes 32 play an important role in moving the liquid through the outlets 13 as the vanes 32 rotate. The larger the side surface area of ​​the vanes 32, the greater the amount of liquid that can be pumped in a given period of time. However, for the pump 1 to operate effectively, the cross-section S1 of the outlet inlet 13a should be configured based on the amount of water driven by the vanes 32. For example, if S1 is too large, the space formed in the outlet inlet 13a is not sufficiently utilized. Conversely, if S1 is too small, not all of the liquid driven by the vanes 32 can enter the outlet 13. Therefore, the preferred size of the cross-section S1 of the outlet inlet 13a of the outlet 13 is defined by S1 = Y x (πbD1), where 0.01 ≤ Y ≤ 0.02.

[0036] It is understood that the shape of the wings 32 is not limited to that described above or in the Fig. 5A-C. For example, the Fig. 6A and Fig. 6B shows an alternative drive wheel 30 according to a second embodiment. In this embodiment, the vanes 32 have a cross-section that is substantially T-shaped (e.g., with a central portion extending beyond a pair of side portions), with an axial height of an outer surface of the vanes 32 defined as h.

[0037] The diffuser has a diffusion coefficient C d , which can be defined by the formula Cd=(s2π−s1π) / L, where L corresponds to a distance between the outlet inlet 13a and the outlet outlet 13b. If C d is too small, the diffusion effect may not be sufficient. If C dHowever, if the cross section is too large, this can lead to greater separation of the fluid flow, which is detrimental to the fluid pressure. In some embodiments, the cross sections S1 and S2 are specified as 0.0035 ≤ C d ≤ 0.07 to achieve a desired diffusion effect.

[0038] In addition, the ratio of the diameter of the chamber 19, D v , to the diameter D1 defined by the vanes 32 is an important consideration. If the ratio D v / D1 is too small, the gap between the vanes 32 and the side wall of the chamber 19 is too small, which leads to the fluid flow rate being too high and high friction losses occurring. If D v If D1 / D1 is too large, a smaller value of D1 is required, which reduces the pump's efficiency. Preferably, the size of the drive wheel 30 relative to the pump chamber 19 is specified as 1.04 ≤ D v / D1 ≤ 1.1.

[0039] Verbs such as "comprise," "comprise," "contain," and "have," and their variations, in the description and claims of this application are to be understood in an inclusive sense. They indicate the presence of the stated element, but do not exclude the presence of additional elements.

[0040] The invention has been described above with reference to one or more preferred embodiments. However, those skilled in the art will recognize that various modifications are possible. Therefore, the scope of the invention is determined by the appended claims.

Claims

[1] Liquid pump (1), comprising: a pump housing (10) defining a pump chamber (19); an electric motor (20) having a shaft (26) and being attached to the pump housing (10); a drive gear (30) fixed to the shaft (26) and received in the pump chamber (19), the drive gear (30) having a central body (31) and a plurality of vanes (32) extending radially outward from the central body (31); an inlet (12) in fluid communication with the pump chamber (19); and an outlet (13) in fluid communication with the pump chamber (19), the outlet (13) having a first end (13a) adjacent to the pump chamber (19) and a second end (13b) remote from the pump chamber (19), wherein a cross section S1 of the first end (13a) is smaller than a cross section S2 of the second end (13b), wherein the first end (13a) and the second end (13b) of the outlet (13) are separated by a distance L, wherein 0.035≤(s2π−s1π) / L≤0.07 is. [2] A pump (1) according to claim 1, wherein radially outer ends of the vanes (32) of the drive wheel (30) define a circle of diameter D1 and a radially outer surface of a vane (32) of the plurality of vanes (32) has an axial height of b, the cross section S1 of the first end (13a) of the outlet (13) being defined by Y x (πbD1), where 0.01 ≤ Y ≤ 0.

02. [3] Pump (1) according to claim 1 or 2, wherein radially outer ends of the vanes (32) of the drive wheel (30) define a circle of diameter D1 and wherein the pump chamber (19) has a substantially circular cross-section of diameter D v where 1.04 ≤ D v / D1 ≤ 1.

1. [4] Pump (1) according to one of claims 1 to 3, wherein the plurality of vanes (32) are uniformly distributed circumferentially around the central body (31) of the drive wheel (30). [5] Pump (1) according to one of claims 1 to 4, further comprising an end cap (14) sealingly attached to an inner surface of the pump housing (10), wherein the pump chamber (19) is defined by an end wall (11) of the pump housing (10) and the end cap (14), wherein the motor (20) is arranged in the pump housing (10) and is separated from the pump chamber (19) by the end cap (14), and wherein the shaft (26) extends through the end cap (14) for engagement with the drive gear (30) in the pump chamber (19). [6] Pump (1) according to claim 5, further comprising an annular seal (5), wherein a groove (18) receiving the annular seal (5) is formed in a radially outer surface of the end cap (14), and the annular seal (5) forms a sealing connection with the inner surface of the pump housing (10). [7] Pump (1) according to claim 5 or 6, wherein the end cap (14) has a sealing hole plate (17) with a through opening through which the shaft (26) extends, and wherein a sealing ring (6) is arranged in the sealing hole plate (17) and forms a seal between the end cap (14) and the shaft (26). [8] Pump (1) according to claim 7, wherein the sealing ring (6) has an outer region (7) in contact with the sealing hole plate (17) and an inner region (9) in contact with the shaft (26), the inner region (9) having a curved surface such that a first end and a second end of the inner region are in contact with the shaft (26) and a central region of the inner region is spaced from the shaft. [9] Pump (1) according to one of claims 1 to 8, wherein the pump chamber (19) has two outlets (13) arranged such that the direction of rotation of the drive wheel (30) determines through which outlet (13) liquid is pumped.

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