DE102009054933A1 - Fluid inlet device for supplying fluid into a piston pump - Google Patents

Abstract

In the case of a fluid inlet device (42) for supplying fluid into a piston pump (10) with a piston (16), the fluid inlet device (42) being designed as part of the piston (16), the fluid inlet device (42) has at least one elongated one Inflow groove (44) in the axial direction towards the piston (16), and the elongated inflow groove (44) penetrates radially completely through the piston (16).

Description

State of the art

The invention relates to a fluid inlet device for supplying fluid into a piston pump with a piston, wherein the fluid inlet device is formed as a part of the piston. Furthermore, the invention relates to a piston pump with such a fluid inlet device and a vehicle brake system with such a piston pump.

A component of modern vehicle braking systems is a hydraulic unit which is used in motor vehicles, such as passenger cars or trucks, to provide regulated brake pressures to the brake system. For dosing this brake pressure, the hydraulic unit to a pump, which is usually a piston pump, in which a piston is displaceable in a cylinder. The displacement of the piston takes place in a two-stroke. In this case, in a first cycle, a fluid to be delivered, for example brake fluid, is sucked through an inlet valve. In a second cycle, the fluid is expelled through an outlet valve. Such a piston pump is for example off DE 10 2005 017 131 A1 known. Usually, the fluid is supplied to the piston pump via a transverse bore in the piston.

Out DE 100 19 403 A1 Furthermore, a check valve for a piston pump of a vehicle brake system with a valve closing body, a valve spring and a holding part is known. The check valve is made in one piece by injection molding of plastic and connected via the holding part with a piston of the piston pump. The one-piece construction should reduce manufacturing costs and simplify the manufacture or assembly of the piston pump. For introducing brake fluid into the valve, a forming part of the piston is provided with axial grooves on the circumference and radial grooves on one end side. The radial grooves lead through through holes in a peripheral wall of the forming part to the check valve.

The object of the invention is to provide a fluid inlet device for a piston pump is available, which is inexpensive to manufacture, while ensuring a good flow characteristic of the fluid to an inlet valve of the piston pump.

Disclosure of the invention

According to the invention, there is provided a fluid inlet device for supplying fluid to a piston pump with a piston, wherein the fluid inlet device is formed as a part of the piston, and wherein the fluid inlet device has at least one elongate inflow groove in the axial direction to the piston, and the elongated inflow groove the piston fully penetrated radially.

The piston pump comprises a cylinder with a cylinder interior and a piston that can be extended and retracted into the cylinder interior and delimits a high-pressure area in the cylinder interior. For introducing and discharging a fluid into the high-pressure region, the piston pump has on an inflow side a fluid inlet device according to the invention with an inlet valve and on an outflow side an outlet valve. When the piston is extended out of the cylinder, a negative pressure is built up in the high-pressure region and fluid flows through the fluid inlet device and the then opened inlet valve into the high-pressure region. On retraction of the piston into the cylinder, however, the inlet valve is closed and the fluid is forced through the then opened outlet valve into a hydraulic system to perform work.

In the present case, a fluid is to be understood as meaning a liquid, a gas or a liquid-gas mixture, in particular a brake fluid.

The fluid inlet device according to the invention is designed as a part of the piston, that is, it travels in and out of the cylinder and also contributes to the build-up of overpressure and underpressure in the high pressure region. The fluid inlet device is advantageously produced as a separate part, in particular as a forming or injection-molded part. It forms a unit with the rest of the piston.

The fluid inlet device has at least one elongated inflow groove in the axial direction to the piston pump. This at least one elongated Zuströmnut penetrates the piston completely in the radial direction. Thus, in the component forming the fluid inlet device, at least one slot or an elongate opening is provided with an extension in the longitudinal direction of the piston. As a result, a relatively large inflow area for the fluid is made available and thus achieves a good pressure build-up dynamics. Upon extension of the piston from the cylinder and in the presence of a negative pressure in the high pressure region, the fluid is sucked into the piston pump substantially perpendicular to the direction of extension of the piston pump by the fluid inlet device. There are essentially no turbulent flows.

According to the invention, a fluid inlet device is provided which, in particular in the form of a forming or injection-molded component, can be produced inexpensively and in a simple manner with the remaining piston can be connected and installed in the piston pump.

According to a first advantageous development of the fluid inlet device according to the invention, webs are arranged next to the at least one elongated inflow groove, which are resilient in the radial direction.

In such a development, the fluid inlet device has a certain number of elongated Zuströmnuten, which are bounded by elongated webs with an extension direction axially of the piston. That is, elongated Zuströmnuten alternately alternate with elongated webs.

These elongate webs are resiliently configured in the radial direction and can form a frictional connection with a remaining component of the piston (eg, a hollow piston rod), such as by clamping in a cavity of a cup-shaped remainder of the component.

According to a second advantageous development of the fluid inlet device according to the invention, the fluid inlet device has 2 to 10, in particular 5 to 7, elongated inflow grooves.

By means of this development, a fluid inlet device is provided which has 2 to 10, in particular 5 to 7, inflow grooves and a corresponding number of webs. As a result, on the one hand a good Fluideinström- and pressure build-up dynamics accomplished by sufficiently many and large Zuströmnuten. On the other hand, the fluid inlet device can form a stable and firm connection with another component (piston rod) of the piston by clamping the webs in a cavity of the other component.

According to a third advantageous development of the fluid inlet device according to the invention, the fluid inlet device has a shoulder, which forms an inner and outer step, and in which webs are arranged on the inner step, which engage in a cavity of the piston.

The fluid inlet device has, on a side facing another component of the piston, a shoulder which forms an inner and outer step over the cross section of the device. In this development, the elongated webs are formed on the inner step and engage in the cavity of the other component. The other component rests on the one hand with an inner wall on the webs and borders with an end face against the shoulder. As a result, the fluid inlet device can be clamped or clamped particularly well with the housing of the piston.

According to a fourth advantageous development of the fluid inlet device according to the invention, a holding device for holding a valve closing body is further formed on the fluid inlet device.

Preferably, the holding device, in which a valve closing body, such as a ball or a plate, can be movably received integrally formed on the fluid inlet device, in particular in the form of a one-piece forming or injection component. Such a device is particularly inexpensive to produce and easy to mount together with the associated fluid inlet device in the piston pump. Such a holding device is also referred to as a valve housing, valve cage or valve cover.

According to a fifth advantageous development of the fluid inlet device according to the invention, the holding device has at least one latching hook for clamping a counter-pressure means.

This latching hook is suitable to clamp a counter-pressure means, such as a compression spring, in particular a helical, spiral or leaf spring, for exerting a defined pressure on a valve closing body. The latching hook is preferably integrally formed, in particular by injection molding, with the holding device. If a compression spring, such as a helical spring, is clamped by means of the latching hook, this spring holds at its circular end the latching hooks and thus the holding device radially inward together and allows good guidance of the valve-closing body in the holding device.

According to a sixth advantageous development of the fluid inlet device according to the invention, a valve seat is further formed on the fluid inlet device, against which a valve closing body can be pressed.

In such a development, a valve seat is preferably integrally formed, in particular by injection molding, on the fluid inlet device. Against the valve seat, a valve closing body for closing the inlet valve can be pressed. The fluid inlet device forms a component with the valve seat and is inexpensive to produce.

According to a seventh advantageous development of the fluid inlet device according to the invention, a sealing element, in particular a high-pressure sealing ring, is further formed on the fluid inlet device.

The sealing element is preferably formed integrally with the fluid inlet device, such as a forming or injection molded part. The sealing element is designed such that it defines the high-pressure region in the cylinder relative to the piston substantially fluid-tight. Furthermore, the sealing element ensures good guidance of the piston in the cylinder.

Furthermore, the object is achieved according to the invention by a piston pump with a fluid inlet device according to the invention.

Such a piston pump can be produced in a cost-effective manner, in particular by using a fluid inlet device in the form of a forming or injection-molded component, and can be assembled simply in the production process. By means of the use of the fluid inlet device according to the invention, an overall compact construction is made possible. Furthermore, due to the inflow grooves according to the invention, an optimized inflow geometry or good flow properties is ensured, turbulent flows or turbulences of the fluid flowing into the piston pump are minimized.

Furthermore, the object is achieved according to the invention by a vehicle brake system having a piston pump, which comprises a fluid inlet device according to the invention.

Such a vehicle brake system comprises a piston pump which can be produced cost-effectively and at the same time permits reliable operation by means of a good inflow characteristic during the delivery of the fluid into the piston pump.

Brief description of the drawings

Exemplary embodiments of the solution according to the invention are explained in more detail below with reference to the attached drawings, in which:

1 a longitudinal section of a piston pump according to the prior art,

2 the detail II in 1 on an enlarged scale,

3 a longitudinal section of a piston pump according to the invention with associated fluid inlet device according to the section VV in 5 .

4 a perspective view of a first embodiment of a fluid inlet device according to the invention, and

5 a perspective view of a second embodiment of a fluid inlet device according to the invention.

Description of embodiments

In the 1 and 2 is a piston pump 10 The prior art illustrates, inter alia, a piston assembly 12 which consists of a cylinder 14 and a piston slidably mounted therein 16 is formed. The piston assembly 12 further comprises an inlet valve 18 and an exhaust valve 20 , These valves 18 and 20 are intended for the piston 16 in his stroke movement in the cylinder 14 a fluid through an inlet 22 - A transverse bore in the piston - in a high pressure chamber or high pressure area 24 inside the cylinder 14 Aspirate and this fluid through an outlet 26 under pressure again from the high pressure area 24 can bring out. The fluid is present a brake fluid.

The piston 16 is in the axial direction by means of a high pressure area 24 located return spring 28 resiliently biased. The return spring 28 is related to 1 at its left end on the end face of the cylinder 14 supported and urges at its right end against a spring rest 30 , The spring pad 30 is with the piston 16 fixedly coupled, so that the return spring 28 according to the spring support 30 against the piston 16 urges.

Between the piston 16 and the cylinder 14 is also a sealing element 32 arranged with which the high pressure area 24 in the cylinder 14 is sealed. The sealing element 32 is ring-shaped and encloses the piston 16 on the outer lateral surface. At this lateral surface is the sealing element 32 by means of one on the piston 16 pushed valve cage or valve housing 34 of the inlet valve 18 kept stationary. On the valve body 34 is also the spring pad 30 shaped in the form of a paragraph. The thus-supported sealing element 32 lies radially inward against the inner surface of the cylinder 14 to glide along and seal it.

The valve housing 34 is cup-shaped designed as a cage, inside which a helical return spring 36 which is against a spherical closing body 38 urges. The closing body 38 lies thereby (in in 1 and 2 illustrated operating state) on a valve seat 40 at the front of the piston 16 is trained. The closing body 38 gets from this valve seat 40 against the force of the return spring 36 lifted off when the piston 16 based on 1 to the right out of the cylinder 14 is pulled out. In this movement, so the inlet valve 18 opened and fluid is in the high pressure area 24 sucked. The suction of the fluid takes place via the inlet 22 acting as a cross hole in the piston 16 is trained.

3 shows a piston pump according to the invention 10 , The piston pump 10 has - as in the cited prior art - a piston assembly 12 with a cylinder 14 and a piston displaceable therein 16 on. The piston 16 is an inlet valve 18 for supplying fluid to a high pressure area 24 of the cylinder 14 assigned. The cylinder 14 includes an outlet valve (not shown) through which the fluid from the high pressure area 24 of the cylinder 14 is conveyed into a downstream hydraulic system. The piston pump 10 is from a pump housing 65 surround.

The piston 16 In the present case, it is formed from two parts, namely from the fluid inlet device according to the invention 42 according to 4 and one the fluid inlet device 42 partially receiving cylindrical piston rod 66 , The fluid inlet device 42 grabs with the webs 46 resilient in a cavity 54 the piston rod 66 and is in this way with the piston rod 66 clamped non-positively. The piston rod 66 and the fluid inlet device 42 form a piston unit.

The fluid inlet device 42 has to supply the fluid to the inlet valve 18 the piston pump 10 elongated Zutrömnuten 44 with relatively large recesses on. These inflow grooves 44 are arranged such that the fluid via an inlet 22 - A recess in the pump housing 65 - directly radially through the inflow grooves 44 in the inlet valve 18 can flow.

The fluid inlet device 42 is also on an end face of the inlet valve 18 integrally formed. This inlet valve 18 includes a holding device 58 for receiving a valve ball 38 and a valve seat 40 according to the 4 discussed features. The holding device 58 includes four retaining bars 62 , at the ends retaining hooks 64 are arranged. The retaining bars 62 tighten the valve ball 38 elastic and ensure that these from the valve seat 40 can be raised and lowered. A coil spring 36 putting a force on the valve ball 38 exercises and this against the valve seat 40 presses, is from the latch hooks 64 fixed and clamped.

The piston 16 is with a in the high pressure area 24 located return spring 28 resiliently biased. When moving out of the piston 16 out of the cylinder 14 is in the high pressure area 24 built a negative pressure, whereby the valve ball 38 from the valve seat 40 is lifted. Fluid then flows through the inlet 22 and through the inflow grooves 44 the fluid inlet device 42 as well as through the opened inlet valve 18 in the high pressure area 24 ,

When the piston 16 via a (not shown) eccentric drive in the cylinder 14 is moved in, then the valve ball 38 by means of the coil spring 36 against the valve seat 40 pressed; the inlet valve 20 is closed. At the same time opens due to the built-up pressure in the high pressure area 24 the outlet valve and the fluid will be out of the high pressure area 24 challenged.

Furthermore, on an outer circumferential surface of the fluid inlet device 42 a high pressure sealing ring 56 integrally formed, which is radially against an inner circumferential surface of the cylinder 14 invests. The high-pressure sealing ring 56 slides when retracting and extending the piston 16 in the cylinder 14 on the lateral surface of the cylinder 14 over and seals the high pressure area 24 essentially fluid-tight with respect to the cylinder 14 from.

The fluid inlet device 42 according to 4 includes six elongated Zutrömnuten 44 in the axial direction to the piston pump 10 run. The inflow grooves 44 are alternating with elongated webs 46 arranged. They enforce that the webs 46 forming material so radially complete. Due to the radial complete breakthrough form the Zuströmnuten 44 a relatively large flow area and a very short flow path for the fluid. As a result, a good pressure build-up dynamics in the piston pump 10 allows. During the suction of the fluid in the piston pump 10 There are essentially no turbulent flows.

The fluid inlet device 42 according to 4 also has an end face of the inflow grooves 44 and footbridges 46 a paragraph 48 with two steps, namely an inner step 50 and an outer step 52 , being at the inner stage 50 the elongated Zuströmnuten 44 and footbridges 46 are arranged. The bridges 46 are designed so that they spring in the radial direction. As a result of the suspension, the webs 46 in a cavity 54 a remaining component or housing of the piston 16 be clamped. The fluid inlet device 42 then forms with the housing of the piston 16 a non-positive piston unit.

Paragraph 48 is present as a high pressure seal 56 designed. The high pressure ring 56 serves as a sealing element, which is the high pressure area 24 in the cylinder 14 seals (cf. 3 ).

The fluid inlet device 42 is made in one piece as a spray component and thus inexpensive to produce.

The fluid inlet device 42 according to 5 is similar to the fluid inlet device 42 in 4 designed. The fluid inlet device 42 according to 5 is however at the paragraph 48 Furthermore, a holding device 58 and a valve seat 40 in one piece by injection molding on the high-pressure sealing ring 56 on the opposite side of the inflow grooves 44 formed.

The holding device 58 serves to receive and guide a valve closing body, in this case a valve ball 38 , The valve ball 38 is by means of a coil spring 36 as a counterpressure against the valve seat 40 pressed. Such a holding device 58 Also referred to as valve body, valve cage or valve cover.

The holding device 58 is made of four elongated retaining struts 62 formed, at the ends in each case a latching hook 64 is arranged. The retaining bars 62 are resiliently supported in the radial direction and tension the valve ball 38 with a guide play, leaving the valve ball 38 from the valve seat 40 can be raised and lowered. The coil spring 36 lies with one end on the valve ball 38 on and is with their other end in the snap hook 64 clamped. The coil spring 38 thus exerts on the one hand a pressure on the valve ball 38 and presses it against the valve seat 40 , On the other hand exercises the coil spring 38 a pressure on the latching hook 64 in the axial direction. Among other things, this pressure prevents the locking hooks 64 during operation of the piston pump 10 could diverge in the radial direction.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005017131 A1 [0002]
• DE 10019403 A1 [0003]

Claims (10)

Fluid inlet device ( 42 ) for supplying fluid into a piston pump ( 10 ) with a piston ( 16 ), wherein the fluid inlet device ( 42 ) as a part of the piston ( 16 ), characterized in that the fluid inlet device ( 42 ) at least one elongated inflow ( 44 ) in the axial direction to the piston ( 16 ), and the elongated Zussömnut ( 44 ) the piston ( 16 ) Radially completely penetrated. Fluid inlet device ( 42 ) according to claim 1, characterized in that webs ( 46 ) next to the at least one elongate inflow groove ( 44 ) are arranged, which are designed resiliently in the radial direction. Fluid inlet device ( 42 ) according to claim 1 or 2, characterized in that the fluid inlet device ( 42 ) 2 to 10, in particular 5 to 7, elongated Zuströmnuten ( 44 ) having. Fluid inlet device ( 42 ) according to claim 2 or 3, characterized in that the fluid inlet device ( 42 ) a paragraph ( 48 ) having an inner and outer stage ( 50 . 25 ), and webs ( 46 ) at the inner stage ( 50 ) arranged in a cavity ( 54 ) of the piston ( 16 ) intervene. Fluid inlet device ( 42 ) according to one of the preceding claims, characterized in that at the fluid inlet device ( 42 ) further comprises a holding device ( 58 ) for receiving a valve closing body ( 38 ) is formed. Fluid inlet device ( 42 ) according to claim 5, characterized in that the holding device ( 58 ) at least one latching hook ( 64 ) for clamping a counter-pressure means ( 36 ) having. Fluid inlet device ( 42 ) according to one of the preceding claims, characterized in that at the fluid inlet device ( 42 ) a valve seat ( 40 ) is formed, against which a valve closing body ( 38 ) is depressible. Fluid inlet device ( 42 ) according to one of the preceding claims, characterized in that at the fluid inlet device ( 42 ) further a sealing element ( 56 ), in particular a high-pressure sealing ring ( 56 ), is formed. Piston pump ( 10 ) with a fluid inlet device ( 42 ) according to any one of the preceding claims. Vehicle brake system with a piston pump ( 10 ) according to claim 9.

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