DE10019403A1 - Check valve for piston pump has holding component for valve shut-off element and is movably connected to it and formed in one piece with it - Google Patents

Abstract

The check valve(34) has a holding component(46) for the valve shut-off element(36) and is movably connected to it and formed in one piece with it. The check valve has a valve spring(38) formed in one piece with the valve element or in one piece with the holding component. The holding component has a valve seat(30) which interacts with the valve shut-off element. The holding component has a valve lift limiter.

Description

State of the art

The invention relates to a check valve for a piston pump according to the Genus of the main claim. The check valve is especially for Use in a piston pump of a slip control device having hydraulic vehicle brake system provided.

Such a check valve is known for example from DE 41 07 979 A1. The known check valve is at one end of a piston Piston pump arranged, the piston pump for conveying Brake fluid in a hydraulic, a slip control device having vehicle brake system is provided. The piston points Axial hole, the mouth of which forms a valve seat of the check valve. A ball arranged on the valve seat forms a valve closing body of the known check valve. In a manner known per se is included closed check valve the ball forming the valve closing body sealing on the valve seat and is open when the check valve is open Valve seat lifted off.  

The disadvantage is that the valve closing body of the known check valve is a separate component and that the check valve when assembled several parts, at least the valve closing body and the valve seat having pistons, and in addition, if necessary, a valve closing spring Include valve housing and / or a guide for the valve closing body, must be put together. Another disadvantage of the known Check valve is provided that a guide for the valve closing body must become.

Advantages of the invention

The check valve according to the invention with the features of claim 1 has a holding part for the valve closing body with which the Valve closing body movably connected and with which the valve closing body is in one piece. About the holding part is the valve closing body with the Check valve connected. The check valve according to the invention has the The advantage that its manufacture and in particular its assembly is simplified are. One-piece manufacture of the entire check valve is included in the Embodiments of the invention possible. The holding part of the invention Check valve can for example form a valve housing and / or Attach the valve closing body to the piston of a piston pump.

The subclaims have advantageous refinements and developments the subject of the invention specified in the main claim.

A further development of the invention provides that the valve closing body is in one piece to train with a valve spring (claim 2). The valve spring itself can also form the holding part of the valve closing body. According to claim 3 the valve spring connects the valve closing body in one piece with the holding part. These refinements of the invention have the advantage that the number of the individual parts of the check valve is reduced, which increases the number of  Manufacturing steps for the individual parts of the check valve and Assembly steps when assembling the check valve reduced.

According to claim 4, the holding part has a valve seat of the check valve with which the valve closing body for opening and closing the Check valve cooperates in a conventional manner. This Embodiment of the invention enables one-piece manufacture of the Check valve according to the invention.

In one embodiment of the invention, the check valve has one with the Holding part one-piece valve stroke limitation (claim 5). The Valve stroke limitation limits a distance by which the valve closing body by a valve seat can be lifted off. The valve stroke limitation has the advantage that a closing time of the check valve is limited. Furthermore forms the Valve stroke limitation a kind of guide that the valve closing body open check valve holds in an intended position, which is a closing the check valve ensures in the intended manner.

In one embodiment of the invention according to claim 6 is the Valve closing body, for example, via a flexible plastic band or Tab pivotally connected to the holding part. This configuration of the The invention has the advantage on the one hand that the valve closing body on the holding part is guided and on the other hand the advantage that the valve closing body through Swiveling when opening opens a large flow cross-section.

In a preferred embodiment of the invention, the valve closing body is in one piece with the holding part and the valve spring, if there is one, made in one piece from plastic (claim 7). The production takes place according to Claim 8 in particular in one operation quickly and inexpensively Injection molding.  

The check valve according to the invention is an inlet or outlet valve Piston pump and in particular for attachment to an end face of a Piston of the piston pump provided. The piston pump is according to the invention provided in particular as a pump in a brake system of a vehicle and is used when controlling pressure in wheel brake cylinders. Depending on the type of Brake system are the abbreviations ABS for such brake systems or ASR or FDR or EHB used. The pump is used in the brake system for example to return brake fluid from a Wheel brake cylinder or from several wheel brake cylinders in a main brake cylinder (ABS) and / or for pumping brake fluid from one Storage container in one wheel brake cylinder or in several wheel brake cylinders (ASR or FDR or EHB). The pump is used for example at a Brake system with a wheel slip control (ABS or ASR) and / or with one as a steering aid brake system (FDR) and / or at a electro-hydraulic brake system (EMS) required. With the wheel slip control (ABS or ASR) can block the wheels of the vehicle, for example during a braking process with strong pressure on the brake pedal (ABS) and / or a spinning of the driven wheels of the vehicle in strong Pressure on the accelerator pedal (ASR) can be prevented. With a steering aid (FDR) serving brake system is independent of an operation of the brake pedal or accelerator pedal a brake pressure in one or more wheel brake cylinders constructed, for example, to break out of the vehicle from the Prevent driver's desired lane. The pump can also be used with an electro hydraulic brake system (EMS), in which the pump is used Pumps brake fluid into the wheel brake cylinder or into the wheel brake cylinder, when an electric brake pedal sensor actuates the brake pedal detected or at which the pump to fill a memory of the brake system serves.

drawing

The invention is preferred below with reference to the drawing selected exemplary embodiments explained in more detail. Show it:

Figure 1 is an axial section of a first embodiment of a piston pump with a check valve according to the invention.

FIG. 2 shows the check valve from FIG. 1 in a perspective view;

Figure 3 is a detail view according to arrow II in Figure 1 of a modified embodiment.

Fig. 4 shows a second embodiment of the invention;

Fig. 5 shows a third embodiment of the invention;

Fig. 6 shows an inventive non-return valve of the piston pump of Figure 5 in axial section as a single part.

FIG. 7 shows a modification of the embodiment of the invention shown in FIG. 5; and

Fig. 8 shows an inventive non-return valve of the piston pump of FIG. 7 as a single part in side view.

Description of the first embodiment

The piston pump 10 shown in FIG. 1 is inserted into a hydraulic block 12 , which forms a pump housing and is referred to below as such. The hydraulic block 12 , of which only a fragment surrounding the piston pump 10 is shown in the drawing, contains a hydraulic control circuit of a slip-controlled vehicle brake system, which is otherwise not shown. In addition to the piston pump 10, other hydraulic components, not shown, such as solenoid valves, are inserted into the hydraulic block 12 and hydraulically connected to one another.

The hydraulic block forming the pump housing 12 is provided with a pump bore 14 into which a hollow cylindrical bushing 16 is inserted, which has a bushing base 18 which is integral with it.

The piston pump 10 has a piston 20 which is guided axially displaceably over part of its length in the liner 16 and on another part of its length protruding from the liner 16 in the pump bore 14 . The pump bore 14 and the liner 16 form a piston guide 14 , 16 . The piston 20 is composed of two parts substantially, it has a sleeve-shaped part 22 and an inserted into the formed part 22 valve seat member 24. The shaped part 22 is produced by deep drawing from a metal sheet, it has the shape of a hollow cylindrical sleeve which is closed on one side with an end wall 26 which is integral with the shaped part 22 . To increase the wear resistance, the formed part 22 is hardened, no other processing takes place, a surface quality of the formed part 22 is sufficient.

The valve seat part 24 pressed into the formed part 22 is made of plastic, it has approximately a cylindrical shape and projects from the formed part 22 with part of its length. The valve seat part 24 is penetrated by a continuous axial hole 28 , which opens out on a side of the valve seat part 24 protruding from the deformed part 22 with a conical valve seat 30 .

The valve seat part 24 has a circumferential sealing lip 32 in one piece with it on its area protruding from the shaped part 22 . The sealing lip 32 , which forms a piston seal, has the shape of a hollow truncated cone and has a free edge in the direction of the liner bottom 18 . The sealing lip 32 rests with a prestress on the inside of the liner 16 and seals the piston 20 in the liner 16 . The sealing lip 32 forms a piston seal on the high-pressure side; it is acted upon on the inside by the fluid (brake fluid) to be delivered with the piston pump 10 . If the pressure of the brake fluid rises during delivery, the sealing lip 32 loaded with the brake fluid is pressed more strongly against the bushing 16 in addition to its pretension, so that the sealing lip 32 also reliably seals against high pressure. At low or constant pressure, the sealing lip 32 seals due to its pretension. In this way, a reliable seal with different brake fluid pressures occurring during operation is achieved with low friction and low wear of the sealing lip 32 .

At the present in the bush 16, the front end of the piston 20 and the valve seat portion 24, an inventive non-return valve 34 is mounted, which is shown in magnification in Fig. 2. The check valve 34 has a hemispherical valve closing body 36 which interacts with the valve seat 30 of the valve seat part 24 . On a flat circular surface facing away from the valve seat 30 , the valve closing body 36 has a valve spring 38 which is integral with the valve closing body 36 . The valve spring 38 has a zigzag shape; it presses the valve closing body 36 against the valve seat 30 in the axial direction with a small preload force.

At one end remote from the valve closing body 36 , the valve spring 38 merges in one piece into a spring holder 40 , which in the exemplary embodiment shown is designed as an angle. One leg 42 of the spring holder 40 is arranged in a radial plane of the piston pump 10 and another leg 44 of the spring holder 40 is arranged approximately axially parallel in the region of a circumference of the valve seat part 24 . The spring holder 40 merges in one piece into a tubular holding part 46 which is placed on the end of the valve seat part 24 located in the liner 16 . The valve closing body 36 , the valve spring 38 , the spring holder 40 and the holding part 46 are produced in one piece with one another as an injection molded part made of plastic in a common mold or injection mold.

On its outer circumference, the tubular holding part 46 of the check valve 34 has an annular step 48 , which forms a support surface 48 for a piston return spring 50 of the piston pump 10 . The piston return spring 50 is designed as a helical compression spring which is inserted into the liner 16 . The piston return spring 50 is supported on the bushing bottom 18 and presses against the the support surface 48 forming the annular step 48 of the retainer 46 of the check valve 34th Via the holding part 46 , the piston return spring 50 presses the piston 20 against the circumference of an eccentric 52 which can be driven by an electric motor and which is arranged on an end face of the piston 20 protruding from the liner 16 . By rotating the eccentric 52 , the piston 20 is driven in a manner known per se to a stroke movement axially reciprocating in the pump bore 14 and in the liner 16 , which causes brake fluid to be conveyed in a manner known per se. At the same time, the piston return spring 50 holds the holding part 46 of the check valve 34 on the front end of the valve seat part 24 of the piston 20 located in the liner 16 .

For the admission of brake fluid, the valve seat part 24 is provided on a part pressed into the formed part 22 with axial grooves 54 on the circumference and with radial grooves 56 on the end face, which lead from through holes 58 punched out of a circumferential wall of the formed part 22 to the axial hole 28 of the valve seat part 24 . The fluid inlet takes place through an inlet bore 60 made in the pump housing 12 , which opens radially into the pump bore 14 , and further through the through holes 58 and the axial and radial grooves 54 , 56 into the axial hole 28 to the check valve 34 according to the invention, which is an inlet valve 34 of the piston pump 10 forms. The fluid to be pumped passes through the check valve 34 from the axial hole 28 into a pump chamber 61 .

The outlet from the pump chamber 61 of the piston pump 10 takes place through a center hole 62 in the liner bottom 18 , which opens out on an outside of the liner bottom 18 with a conical valve seat 64 of an outlet valve 66 . The outlet valve 66 is designed as a spring-loaded check valve. A helical compression spring as the valve spring 68 presses a valve ball 70 forming a valve closing body against the valve seat 64 . The valve ball 70 and the valve spring 68 are inserted into an axial blind hole 72 in a sealing plug 74 which is placed on the liner bottom 18 . The sealing plug 74 is fastened with a circumferential caulking 76 of the pump housing 12 in the pump bore 14 and is sealed pressure-tight. The brake fluid flowing out through the outlet valve 66 is discharged through radial channels 78 arranged in a star shape between the sealing plug 74 and the liner bottom 18 into the pump bore 14 and from there through an outlet bore 80 made radially to the pump bore 14 in the pump housing 12 .

The valve closing body of the check valve 34 according to the invention need not have a spherical shape, other shapes are also possible. For example, the valve closing body 82 can be designed as a circular disk as shown in the detail view of FIG. 3. In this embodiment variant, the valve seat 30 is formed by a peripheral edge provided on the valve seat part 24 . The edge forming the valve seat 30 is located on an end face of the valve seat part 24 facing the pump chamber 61 . For the rest, the check valve 34 and the piston pump 10 in FIGS. 1 and 3 are of the same design and function in the same way. To avoid repetition, reference is made to the above explanations for FIG. 1. The same reference numbers are used for the same components.

There is a latching connection 81 between the piston 20 and the holding part 46 of the check valve 34 . The latching connection 81 is formed by a circumferential bead 85 on an inner circumferential surface of the holding part 46 , which engages in a circumferential groove on the outer circumference of the valve seat part 24 . Because of the latching connection 81 , the piston 20 and the check valve 34 can be firmly plugged together before the piston 20 is installed in the pump housing 12 . This considerably simplifies the assembly of the piston pump 10 .

Description of the second embodiment

The same reference numerals are used to describe the piston pump 10 shown in FIG. 4 for the same components as FIG. 1. In contrast to the piston pump 10 from FIG. 1, which is designed as a single piston pump, the piston pump 10 from FIG. 4 is designed as a stepped piston pump. This means that the piston 20 of the piston pump 10 from FIG. 4 is guided and sealed in the liner 16 to a larger diameter than outside the liner 16 in the pump bore 14 in the pump housing 12 . Due to the design as a stepped piston pump, the piston pump 10 from FIG. 4 has an annular space 83 surrounding the shaped part 22 of the piston 20 in the pump bore 14 or in the liner 16 . A volume of this annular space 83 changes during the reciprocating stroke movement of the piston 20 and causes brake fluid to be sucked in even during a delivery stroke of the piston pump 10 .

The check valve 34 according to the invention of the piston pump 10 from FIG. 4 forming the inlet valve has a valve closing body 84 which has the shape of a circular disk. The valve closing body 84 is integral with the valve seat part 24 , which is part of the piston 20 and pressed into the shaped part 22 of the piston 20 , via a tab 86 made of plastic. The valve seat part 24 of the piston 20 also forms the holding part 46 of the check valve 34 according to the invention. The valve closing body 84 is produced in one piece and in one operation by injection molding with the valve seat part 24 forming the holding part 46 , with which the valve closing body 84 is pivotally connected via the tab 86 . When viewed in the radial direction, the tab 86 is quite thin. Can thereby be achieved that 84 within the tab 86, only small bending stresses occur during a pivoting movement of the valve closing body, which the durability of tab 86 substantially extended. The thickness of the tab 86 is preferably only 0.5 mm to 1 mm.

When the check valve 34 is closed, the valve closing body 84 lies sealingly against the mouth of the axial hole 28 in the valve seat part 24 . A circumferential front edge of the mouth forms the valve seat 30 of the check valve 34 . When the check valve 34 is opened , the valve closing body 84 lifts off the valve seat 30 with a pivoting movement, the valve closing body 84 being pivotably guided on the valve seat part 24 by the tab 86 connecting it to the valve seat part 24 .

The pivoting angle by which the valve closing body 84 can be lifted off the valve seat 30 is limited by a hook 88 , which is also integral with the valve seat part 24 of the piston 20 forming the holding part 46 of the check valve 34 and which is axially parallel to the valve seat part 24 on the circumference of the valve closing body 84 stands out. The hook 88 forms a valve stroke limitation 88 . It limits a valve lift, that is to say the swivel angle or the distance by which the valve closing body 84 can be lifted off the valve seat 30 . In this embodiment of the invention, all parts of the check valve 34 , namely its holding part 46 , the valve closing body 84 pivotally connected to the holding part 46 via the tab 86 , and the valve stroke limiter 88 are made in one piece and are made from plastic by injection molding. The check valve 34 therefore does not require any assembly steps for its individual parts; it is ready for operation immediately after it has been removed from the mold. Because the valve closing body 84 lifts only slightly from the valve seat 30 because of the valve stroke limitation 88 , the check valve 34 can be closed very quickly at the beginning of the delivery stroke. A special valve closing spring can therefore be dispensed with and the tab 86 can be designed to be very flexible.

The snap-in connection 81 provided between the support ring 90 and the valve seat part 24 of the piston 20 substantially reduces the effort involved in assembling the piston pump 10 .

The piston return spring 50 is supported in the piston pump 10 shown in FIG. 4 via a support ring 90 on the piston 20 , the support ring 90 being placed on the valve seat part 24 in the inner region of the sealing lip 32 .

Furthermore, the piston pump 10 shown in Fig. 4 agrees with the in Fig. 1 the piston pump 10 shown consistent and operates in the same way. To avoid repetition, reference is made to the comments on FIG. 1.

Description of the third embodiment

The piston pump 10 shown in FIG. 5 is designed like the piston pump from FIG. 4 as a stepped piston pump. Its piston 20 has sleeve-shaped shaped parts 24 , 92 , which are produced by deep drawing from a metal sheet. Both shaped parts 24 , 92 have a hollow cylindrical, stepped shape and are integral on one end with an end wall 26 , 94 . The two forming parts 24 , 92 are pressed into one another, both forming parts 24 , 92 being open in the same direction, namely in the direction of the liner 16 . The end wall 94 of the inner forming part 92 is provided with a center hole 96 for the passage of brake fluid.

A check valve 34 according to the invention is pressed into the internal molded part 92 of the piston 20 . The check valve 34 of the piston pump 10 shown in FIG. 4 is shown individually in an axial section in FIG. 6. The check valve 34 has a hollow cylindrical holding part 98 , which bears on the end wall 94 of the inner shaped part 92 of the piston 20 provided with the central hole 96 for the passage of brake fluid. An end edge of the holding part 98 facing away from the end wall 94 forms a valve seat 99 of the check valve 34 ; the holding part 98 is thus also a valve seat part. On the side of the holding part 98 facing away from the end wall 94 , a valve closing body 100 of the check valve 34 is arranged, which is cylindrical. The valve closing body 100 is connected to the holding part 98 so that it can be lifted and pivoted via a tab 102 arranged at one point on its circumference. The tab 102 is arranged axially parallel on a circumference of the valve closing body 100 and the tab 102 is corrugated. By stretching the tab 102 in the axial direction of the valve closing body 100 can stand out from the holding part 98 and the valve closing body 100 can be pivoted from the holding part 98 of the check valve 34th

Also in this embodiment of the check valve 34 according to the invention all parts of the check valve 34, namely, the holding part 98 and the associated over the tab 102 with the holding portion 98 of the valve closing body 100 are made in one piece and in each one working step by injection molding of plastic; there is no need to assemble the check valve 34 from individual parts.

When the check valve 34 is closed, its valve closing body 100 lies sealingly against the valve seat 99 of the holding part 98 . When opening the valve closing body is lifted off 100 by stretching the tab 102 from the holding part 98 and it pivots, so that it releases a large flow cross-section.

The bushing 16 of the piston pump 10 shown in FIG. 5 is made from a metal sheet by deep drawing. The liner 16 has a cylindrical shape with a bottom 104 on one end face. A free edge 106 of the liner 16 is flanged inwards, it holds the piston 20 on an annular step 108 in the liner 16 . A piston return spring 50 , which is designed as a helical compression spring, is inserted into the liner 16 . The piston return spring 50 is supported on the bottom 104 of the liner 16 and presses against an annular step 110 inside the piston 20 , which is formed on the inner molded part 92 of the piston 20 .

A center hole 112 is made in the bottom 104 of the liner 16 , the mouth of which forms a valve seat 64 of a check valve 66 . The check valve 66 forms an outlet valve of the piston pump 10. Like the outlet valve 66 of the piston pump 10 shown in FIG. 1, it is designed as a spring-loaded check valve with a valve ball 70 as a valve closing body.

For the rest, the piston pump 10 shown in FIG. 5 is of the same design and functions in the same way as the piston pump 10 shown in FIG. 1, and reference is made to the statements relating to FIG. 1.

The check valve 34 is pressed into the cup-shaped shaped part 92 via its cylindrical holding part 98 . This creates a clamping pressure 103 between the check valve 34 and the piston 20 . The clamping pressure 103 ensures that the fluid cannot flow back into the inlet bore 60 from the pump chamber 61 bypassing the check valve 34 . In addition, the clamping pressure 103 holds the check valve 34 firmly on the piston 20 not only during the operation of the piston pump 10 , but also before and during the assembly of the piston pump 10 . As a result, the outlay for producing the piston pump 10 is substantially reduced overall.

In the piston pump 10 shown in FIG. 7, the check valve 34 , which is shown individually in side view in FIG. 8, is designed differently from the check valve 34 of the piston pump 10 shown in FIG. 5. In contrast to FIG. 5, the check valve 34 of the piston pump 10 from FIG. 7 has several, for example three, tabs 102 which connect the valve closing body 100 to the holding part 98 . The tabs 102 are distributed over the circumference and are corrugated. To open the check valve 34 , the tabs 102 can be stretched due to their corrugation, so that the valve closing body 100 can be lifted axially from the holding part 98 . A pivoting of the valve closing body 100 is not possible here. The provision of a plurality of tabs 102 has the advantage of improved guidance of the valve closing body 100 on the holding part 98 and of a spring force exerted by the tabs 102 in the closing direction of the valve closing body 100 . At the same time, the tabs 102 form a valve stroke 88, which limit the valve, ie the distance by which the valve closing body 100 can be lifted from the holding part 98.

In the exemplary embodiment shown in FIGS . 7 and 8, the valve lift limiter 88 ensures that the valve closing body 100 only lifts off the valve seat 99 to a limited extent, so that the check valve 34 can close very quickly at the beginning of a delivery stroke, as is also the case in FIG Fig. 4 illustrated embodiment is explained.

Except for the difference mentioned that the check valve 34 of the piston pump 10 shown in FIG. 7 has several (three) tabs 102 , which connect the valve closing body 100 in one piece to the holding part 98 of the check valve 34 , this check valve 34 is constructed in the same way and functions in the same way manner as that of FIG. 5 and 6, there reference is made to the statements relating to FIGS. 5 and 6. The piston pump 10 from FIG. 7 is also constructed in accordance with that from FIG. 5 and functions in the same way, so that reference is also made here to the statements relating to FIG. 5.

Claims (11)

1. Check valve for a piston pump, the check valve having a valve closing body, characterized in that the check valve ( 34 ) has a holding part ( 46 ; 98 ) for the valve closing body ( 36 ; 82 ; 84 ; 100 ) with which the valve closing body ( 36 ; 82 ; 84 ; 100 ) movably connected and with which the valve closing body ( 36 ; 82 ; 84 ; 100 ) is in one piece. 2. Check valve according to claim 1, characterized in that the check valve ( 34 ) has a valve spring ( 38 ; 102 ) with which the valve closing body ( 36 ; 82 ; 100 ) is in one piece. 3. Check valve according to claim 2, characterized in that the valve spring ( 38 ; 102 ) is in one piece with the holding part ( 46 ; 98 ). 4. Check valve according to claim 1, characterized in that the holding part ( 46 ; 98 ) has a valve seat ( 30 ; 99 ) with which the valve closing body ( 36 ; 82 ; 84 ; 100 ) cooperates. 5. Check valve according to claim 1, characterized in that the holding part ( 46 ; 98 ) has a valve stroke limitation ( 88 ; 102 ). 6. Check valve according to claim 1, characterized in that the valve closing body ( 84 ; 100 ) is pivotally connected to the holding part ( 46 ; 98 ). 7. Check valve according to claim 1, characterized in that the valve closing body ( 36 ; 82 ; 94 ; 100 ) is made in one piece with the holding part ( 46 ; 98 ) made of plastic. 8. Non-return valve according to claim 6 or 7, characterized in that the valve closing body ( 36 ; 82 ; 84 ; 100 ) is an injection molded part made of plastic with the holding part ( 46 ; 98 ). 9. Check valve according to one of the preceding claims, characterized in that the valve closing body ( 36 ; 82 ; 84 ; 100 ) is integrally connected to the holding part ( 46 ; 98 ) via at least one flexible tab ( 86 ; 102 ). 10. Check valve according to one of the preceding claims, characterized in that the holding part ( 46 ; 98 ) via a latching connection ( 81 ) is connected to a piston ( 20 , 22 , 24 ; 92 ). 11. Check valve according to claim 1, characterized in that between the check valve ( 34 ) and a piston ( 20 ) a clamping pressure ( 103 ) is provided which holds the check valve ( 34 ) on the piston ( 20 ).