Positive displacement pump and method for manufacturing a positive displacement pump

Abstract

The invention relates to a positive displacement pump, in particular a vane pump, for a motor vehicle, comprising: a rotor (5), wherein in the peripheral surface of the rotor (5) over the width of the rotor (5) substantially radially extending slits are arranged in which radially movable vanes are guided; a cam ring (3), wherein the rotor (5) rotates in the cam ring (3); and wherein the cam ring (3) is closed from each side with an end plate (6) forming a housing and with a control plate (8); wherein the end plate and control plate (6, 8) are produced by a casting process; and wherein the end plate and / or control plate (6) contain inserts (7a, 7b) which minimize wear at the end plate and control plate (6, 8) at specific points.

Description

Technical Field

[0001] This invention relates to a positive displacement pump, particularly a vane pump for conveying fluid to the load of a motor vehicle. Furthermore, this invention also relates to a method for manufacturing a positive displacement pump, particularly a vane pump. Background Technology

[0002] Positive displacement pumps are known for providing a pressurized medium flow to a load in a motor vehicle. These pumps are, for example, constructed as vane pumps, in which a rotor rotates within a cam ring. The cam ring is closed from each side by end plates forming the housing and by a control plate. The cam ring has a profile extending coaxially with respect to the rotor's axis and forms the pump space. In the circumferential surface of the rotor, substantially radially extending slots are arranged within the width of the rotor, guiding radially movable vanes within these slots. As the rotor rotates about its axis, the vanes are guided along the profile of the cam ring, wherein chambers with varying volumes are formed between each pair of adjacent vanes.

[0003] Currently, end plates and control plates are mostly manufactured using aluminum pressure casting. Aluminum is used primarily for cost reasons, but it is relatively softer than steel. Consequently, especially in transmission applications, this material tends to increase wear. Increased wear, or cavitation, occurs partly when vigorous foaming fluids are used inside the transmission mechanism and under specific operating conditions. This can be seen, for example, in cam rings embedded in the functional surfaces of end plates and control plates, and can also manifest as cavitation wear.

[0004] As an alternative, the end plate and control plate can be manufactured by casting or sintering steel. However, this is significantly more expensive and negatively impacts the pump's weight. Furthermore, wear-resistant coatings are known to be used, but these coatings only provide limited wear resistance and further increase cost. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide a positive displacement pump, particularly a vane pump, for conveying fluid to a load, wherein wear at the end plate and control plate is minimized, and wherein the positive displacement pump should remain inexpensive. Furthermore, the present invention also provides a method for manufacturing such a positive displacement pump.

[0006] The task is accomplished by a positive displacement pump, particularly a vane pump, according to the invention, comprising: a rotor, wherein a substantially radially extending slit is arranged in the circumferential surface of the rotor within the width of the rotor, in which radially movable vanes are guided; a cam ring, in which the rotor rotates; and wherein the cam ring is closed from each side by end plates forming a housing and by control plates; wherein the end plates and control plates are manufactured by an aluminum pressure casting process; the end plates and / or control plates include inserts made of steel that minimize wear at the end plates and control plates at specific locations within the contour of the cam ring, wherein the end plates and / or control plates include the inserts at specific locations within the contour of the cam ring where increased fluid-induced wear occurs, wherein the inserts are positioned at the ends of grooves. Furthermore, the task is accomplished using a method for manufacturing the positive displacement pump according to the invention, comprising the steps of: providing a pressure casting mold; positioning one or more wear-resistant inserts in the pressure casting mold, the inserts being capable of minimizing wear on the positive displacement pump; filling the pressure casting mold with aluminum; and removing the casting.

[0007] Increased wear always occurs at specific locations on the end plates and control plates. To specifically protect these locations, according to the invention, wear-resistant inserts are positioned in the casting mold during the casting process. The end plates and control plates are typically cast using an aluminum pressure casting process. The components are cast. Finally, the casting is removed.

[0008] The insert can be, for example, a square or cylindrical component made of steel. Attached Figure Description

[0009] The embodiments are illustrated with reference to the accompanying drawings. Wherein: Figure 1 The structure of a vane pump is shown; Figure 2 An end plate of a vane pump according to the invention is shown; Figure 3 A cross-section of the end plate according to the invention is shown. Detailed Implementation

[0010] The positive displacement pump is constructed as a vane pump. Figure 1 The common structure of a vane pump is visible. An outer ring 2 and a cam ring 3 are inserted into a housing 1, and a drive shaft 4 carrying a rotor 5 is placed within the housing 1. A working chamber is constructed between the cam ring 3 and the rotor 5. The working chamber is defined axially by a control plate 8 and an end plate 6. The control plate 8 is essentially designed as a cover.

[0011] exist Figure 2 The end plate 6 of the vane pump according to the invention is visible in the image. The end plate 6 includes wear-resistant inserts 7a, 7b at specific locations. For example, such inserts 7a are positioned at the ends of grooves, where wear often occurs due to cavitation.

[0012] exist Figure 3 The end plate 6 according to the invention is visible in the cross-section. It is evident that the insert 7a is inserted into the aluminum material of the end plate 6.

Claims

1. A positive displacement pump for use in motor vehicles, comprising: Rotor (5), wherein a slit extending substantially radially is arranged in the circumferential surface of the rotor (5) within the width of the rotor (5), and blades capable of radial movement are guided in the slit; Cam ring (3), wherein the rotor (5) rotates in the cam ring (3); and The cam ring (3) is closed from each side by means of the end plate (6) forming the housing and by means of the control plate (8); The end plates and control plates (6, 8) are manufactured using an aluminum pressure casting process; Its features are, The end plate and / or control plate (6, 8) include inserts (7a, 7b) made of steel, which minimize wear on the end plate and control plate (6) at specific locations within the contour of the cam ring (3). The end plate and / or control plate (6, 8) includes the insert (7a, 7b) at a specific location within the contour of the cam ring (3) where increased wear caused by fluid occurs. The insert is positioned at the end of the groove.

2. The positive displacement pump according to claim 1, Its features are, The inserts (7a, 7b) are square or cylindrical components made of steel.

3. A method for manufacturing a positive displacement pump according to claim 1, comprising the steps of: Provide pressure casting molds; One or more wear-resistant inserts (7a, 7b) are positioned in the pressure casting mold, the inserts (7a, 7b) being able to minimize the wear of the positive displacement pump; The pressure casting mold is filled with aluminum; Remove the casting.

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