DE102007048242A1 - Piston pump sub-assembly for use in piston pump of hydraulic brake system of vehicle, has sealing element arranged to counteract transfer of medium to be conveyed from front-sided opening of cylinder sleeve to drive section - Google Patents

Abstract

The sub-assembly (120) has a cylinder sleeve (200) accommodating a piston (190) in an axially displaceable manner and partially supporting the piston. The cylinder sleeve has a front-sided opening to make a reciprocal effect of the piston with a drive section (500). A sealing element (220) accommodated in the cylinder sleeve is provided between the piston and the cylinder sleeve in a sealing manner. The sealing element is arranged to counteract the transfer of a medium to be conveyed from the front-sided opening of the cylinder sleeve to the drive section. An independent claim is also included for a method for mounting a piston pump sub-assembly.

Description

Technical area

The The invention relates to a piston pump. In particular, the invention relates a piston pump for use in the field of hydraulic brake systems of vehicles.

background

hydraulic Braking systems have been used in vehicles for quite some time Type used. For vehicles with driver assistance or driver-independently activated brake systems is common the use of hydraulic pumps that are able to To generate or maintain a hydraulic pressure in the brake system receive. Unlike previous systems where the Hydraulic pumps only low demands on the service life had to satisfy, are in current systems, the automated or semi-automatic brake activations so often, that service lives for the hydraulic pumps in the range of 1000 Operating hours and more are required.

For This task piston pumps have proven, usually be actuated by an electric motor and their pistons To reduce wear in bushings are added. In connection with hydraulically operated brake systems For example, a number of such piston pumps are known in the art.

In the German patent application DE 197 32 817 A1 a piston pump for use in a brake system of a vehicle is described. The piston pump comprises a piston which is accommodated in an axially movable manner in a two-part bush, which in turn is accommodated in a piston pump housing.

At an end face of a first, simultaneously designed as a fluid filter Laufbuchsenteils the piston is partially out and is in engagement with an electric motor driven eccentric element. A first sealing element seals the piston in this area from the piston pump housing. A second Bushing part extends in extension of the first Bushing part in a direction away from the eccentric element, wherein the two bushing parts mitein other engaged. With respect to the second bushing part, the piston is by means of a second sealing element sealed, which stationary with respect of the piston is provided.

to Assembly of the piston pump is initially at least the Piston and the two bushing parts comprehensive subassembly preassembled. The first barrel part here has a over the front edge of the second barrel portion inwardly standing captive on which holds the piston in the two-piece liner. The preassembled subassembly is then in the pump housing used.

The German patent application DE 100 15 295 A1 proposes a similar arrangement to prevent loss of the piston during assembly of a subassembly comprising the piston into a piston pump housing. In contrast to DE 197 32 817 A1 Here is the filter element slidably attached to a bushing part and prevents loss of the piston in that it engages behind an undercut of the piston.

Of the The invention is based on the object of specifying a piston pump, used in a simple way in a pump housing can be and is inexpensive to produce.

Short outline

According to one In the first aspect, a piston pump subassembly includes a piston, an axially displaceable receiving the piston and the piston at least partially supporting bush, wherein the bushing has an end opening, to an interaction of the piston with a drive element to allow, and one in the liner sealing between the piston and the bushing received first sealing element, which is arranged to prevent the passage of a person to be promoted Medium from the front opening of the liner to Counteract drive element.

The first sealing element may be substantially stationary with respect to the bushing be fixed. But it would also be possible to fix the first sealing element on the piston and thus movable with respect to the liner.

at a stationary with respect to the liner first sealing element the first sealing element in a parallel to the axis of movement of the Piston extending direction on one side of a shoulder of the liner be supported. The first sealing element can be immediate rest against the shoulder or by means of a rigid intermediate element be spaced from this.

Furthermore, the first sealing element can be supported on one side in a direction parallel to the axis of movement of the piston by means of a fixing element fastened to the bushing. The fixing may be provided in addition to the above-mentioned shoulder or act in a different direction and, for example by means of egg ner mechanical locking, be fixed by gluing or by a fit to the liner.

The first seal member may near a drive element facing Be arranged front side of the bushing. For example, that can first sealing element at a distance from the end face of the liner be arranged, which is smaller than the approximate diameter of the piston is. In one embodiment, in the area between the first sealing element and the drive element except the Bushing no piston bearing or sealing elements attached.

Between the piston and the bushing, a second sealing element be provided to a transfer of the to be promoted Medium between the piston and the liner of a medium inlet to a medium outlet of the liner and in the reverse direction counteract. The second sealing element can be adapted to any, known to those skilled in the art as a high-pressure seal be low friction forces with a sufficient Combining sealing effect. The material of the first as the second sealing element, for example, on metal, ceramic, Plastic, in particular an elastomer, or rubber based.

The second sealing element may be near a drive element facing away from Be arranged front side of the piston. The piston can rise up the side facing away from the sealing element of the second sealing element but also continue. In one embodiment, the second sealing element further from the drive element facing end side of the liner remotely located as the first sealing element.

The Bushing can be constructed in two or more parts, wherein the Piston may be stored in at least two of the bushing parts. The first and second sealing elements can their sealing effect concerning the same or different bushing parts exercise. The individual barrel parts can immediately adjacent to each other or spaced from each other.

Between at least two adjacent bushing parts can at least one Be arranged connecting element. The at least one connecting element can the bushing parts in a predetermined, minimum, maximum or keep a fixed distance. The at least one connecting element can be connected to one or both adjacent parts of the barrel be.

The Piston pump subassembly may comprise at least one filter element, to impurities in one of the piston pump to be promoted Retain hydraulic fluid. In one embodiment can such a filter element integrated into the liner and, for example be arranged in the region of at least one connecting element.

At least one of the connecting elements may comprise the filter element or fix. The filter element can therefore be integral with the connecting element be formed, for example in the form of a porous Plastic or ceramic material. Alternatively, the filter element be executed separately from the connecting element (ie z. B. bear against webs formed as connecting elements).

The first sealing element can exert a frictional force on the piston, which counteracts falling out of the piston from the liner. Preferably, by the first sealing member on the Piston exerted frictional force as low as possible, to avoid unnecessary friction losses during operation to avoid the piston pump, but at the same time big enough, to prevent falling out of the piston due to gravity and to provide a sufficient sealing effect.

The first sealing element can be designed in the form of a quad-ring be. A quad ring is reminiscent of an integral version two adjacent pairs of concentric O-rings. Alternatively to a Quad-ring can also be any other known sealing element be used, for example, a circumferential elastomer ring with a different cross-sectional shape, a shaft seal or a stuffing box.

According to one The second aspect includes a method of mounting a piston pump subassembly with the features described above the step of mounting the preassembled piston pump subassembly in a piston pump housing. In one embodiment, it is not necessary in the piston pump housing Install additional piston pump elements before the piston pump subassembly is mounted. In particular, for example, no support or sealing elements inserted into the piston pump housing to become.

According to a third aspect, a piston pump comprises at least one piston pump subassembly accommodated in the piston pump housing according to the features described above. In this case, the piston pump may be supported on one or more shoulders of a bore formed in the piston pump housing for the piston pump subassembly. Additionally or alternatively For this purpose, the piston pump subassembly can also be supported on one or more cones (or inclined surfaces) on the piston pump housing.

Short description of the drawing

The single figure shows a schematic view of a longitudinal section by a piston pump according to an embodiment of the present invention.

Description of a preferred embodiment

The single figure shows a piston pump 100 and an actuated and electric motor driven eccentric arrangement 500 , The piston pump 100 includes a piston pump housing 110 in which a piston pump subassembly 120 and a valve subassembly 150 are arranged. Rotates the eccentric arrangement 500 around its axis, so does an oscillating motion on the piston pump subassembly 120 or included pistons 190 transferred, and a hydraulic fluid (not shown) is from a low-pressure channel 130 (Inlet) of the piston pump housing 110 to a high pressure channel 140 (Outlet), as detailed below.

The piston pump housing 110 has a multi-step, in the figure to the left gradually tapered bore 110.5 into which the piston pump subassembly 120 and the valve subassembly 150 are introduced from the right.

The elements of the piston pump subassembly 120 are pre-assembled to a separately manageable unit, which in one operation in the piston pump housing 110 can be mounted. In one embodiment, the piston pump subassembly 150 at least temporarily at the piston pump subassembly 120 be attached before both assemblies together in the piston pump housing 110 to be built in. An attachment can be made for example by a clamping fit or a snap-in connection.

When fully assembled, the piston pump subassembly is supported 120 on her from the eccentric arrangement 500 opposite side to the valve subassembly 150 from. The valve subassembly 150 includes a plug 160 , a feather 170 and a ball acting as a valve element 180 , The stopper 160 is sealing with the piston pump housing 110 connected, for example, by caulking, pressing, gluing, screwing, shrinking, welding, soldering or mechanical locking. In the area between the plug 160 and the piston pump housing 110 may be arranged one or more sealing elements, such as O-rings, flat gaskets, labyrinth seals, etc. The ball 170 and the spring 180 the valve subassembly 150 act as a check valve for hydraulic fluid, as described in more detail below.

The piston pump subassembly 120 includes the already mentioned piston 190 , a first liner part 200. and a second liner part 210 , The piston 190 is in each of the two bushing parts 200. . 210 partially included, and the liner parts 200. . 210 are after assembly of the piston pump subassembly 120 in the piston pump housing 100 sealingly absorbed in this. For this recording, any, known in the art connection technology can be used, for example, one of the above in connection with the plug 160 described connection technology. Each of the liner parts 200. and 210 can be made of plastic, metal, ceramic or other, sufficiently resistant material. In one embodiment, each bushing part can also be designed in several pieces, for example in the form of a multilayer component.

The first liner part 200. is at the cones 110.1 and 110.2 as well as on the shoulder 110.3 of the piston pump housing 110 supported. The cones 110.1 and 110.2 cause a radial pressing action on the first bushing part 200. This in improved condition to the piston 190 holds. The shoulder 110.3 limits movement of the first bushing part 200. in the direction of the left. A seal of the first liner part 200. opposite the piston pump housing 110 can be achieved by means of an optional sealing element (not shown), for example by means of a gasket along the shoulder 110.3 , or by means of a circumferential seal, such as an elastomeric O-ring.

The second liner part 210 is in a respect to the eccentric arrangement 500 distant direction of the first liner part 200. arranged and can be attached to an optional shoulder 110.4 of the piston pump housing 110 be supported in the figure with respect to a movement to the left.

The first liner part 200. takes a quad ring 220 , an investment element 230 and a fixing element 240 on. The quad ring 220 seals the piston 190 opposite the first liner part 200. from. So the quad ring 200. stationary relative to the first bushing part 200. and the movable piston 190 is fixed, he lies on his left in the figure on a flat annular contact element 230 which in turn is on one shoulder 200.4 of the first bushing part 200. supported. This arrangement prevents movement of the quad ring 220 to the left. On its right side is the quad ring 220 on an annular fixing element 240 which is in the first liner part 200. is fixed in place. In one embodiment, the quad-ring suffice 220 on the piston 190 applied radial forces to the piston 190 before and during assembly of the piston pump assembly 110 secure against falling out.

The first liner part 200. covers on its the eccentric arrangement 500 side facing a sleeve section 250 and a connecting element 260 , At its in the figure right front side of the sleeve section 250 on the shoulder 210.1 of the second bushing part 210 at. At its opposite end is the sleeve section 250 with the connecting element 260 also connected to the left in the figure portion of the first liner part 200. connected is. The connecting element 260 also has a shoulder 260.2 on which the left end side of the second bushing part 210 is applied.

The connecting element 260 has the priority task, the sleeve section 250 at a predetermined minimum distance to the left in the figure portion of the first liner part 200. to keep. The connecting element 260 can this example, as an annular, concentric with the piston 190 be arranged element arranged. The connecting element 260 may be porous or may have one or more apertures (not shown) to facilitate exchange of hydraulic fluid between its outer and inner surfaces. In another embodiment, the connecting element 260 in the form of one or more parallel to the axis of the piston 190 be designed extending webs. The connecting element 260 can be integral with the sleeve section 250 and / or the left in the figure portion of the first liner part 200. be formed or as a separate element on one or both of the elements 200. . 250 be attached. The connecting element 260 can be made of plastic, metal, ceramic or other, sufficiently stable material.

The connecting element 260 also stands with the right in the figure, the end face of the fixing 240 in contact and additionally supports this to the right. A filter element 270 is so in the region of the connecting element 260 arranged that there are impurities from a the piston pump 100 flows back through hydraulic fluid. The filter element 270 may be, for example, a nonwoven, a porous solid or a fabric. Indicates the connection element 260 Breakthroughs on, so the filter element 270 be fixed directly in these. Alternatively, the filter element 270 be executed for example in the form of a filter ring and the connecting element 260 or cover its openings from the outside or inside. In one embodiment, the connecting element 260 be made in an injection molding of plastic and integral with the filter element 270 be educated. In yet another embodiment, the filter element 270 in an injection molding process on or in the connecting element 260 be sprayed.

The piston 190 indicates at its from the eccentric arrangement 500 remove front side a coaxial blind hole 280 on. One in the area of the connecting element 260 arranged transverse bore 290 of the piston 190 is in connection with the blind hole 280 , allowing hydraulic fluid through the transverse bore 290 in the pistons 190 enter and through the blind hole 280 can escape again, or vice versa. On his with respect to the cross hole 290 from the eccentric arrangement 500 distant side, the piston points 190 one shoulder 190.1 on, at the a piston seal 300 abuts which the piston 190 opposite the second liner part 210 seals. The piston seal 300 can be like the quad ring 220 for example, on metal, ceramic, plastic, in particular an elastomer, or based on rubber.

The piston seal 300 is on her shoulder 190.1 of the piston 190 facing away from a spring basket 310 at. The spring basket 310 Partially penetrates into the piston seal 300 and carries a widening to the left Außenko nus. The piston seal 300 carries in the contact area an at least partially corresponding inner cone. The spring basket 300 is by a spring 320 , which are in the second liner part 210 supported to the right, pressed to the left. This affects the spring basket 310 a spreading effect on the piston seal 300 what their sealing effect with respect to the second liner part 210 improved. In addition, the left-acting force of the spring cage 310 over the piston seal 300 to the piston 190 passed, so that this pressed to the left and in abutment with the eccentric arrangement 500 is held.

In the spring basket 310 are a feather 330 and a ball acting as a valve element 340 added. The feather 330 rests to the right at the bottom of the spring cage 310 and push the ball 340 one the valve seat 190.2 of the piston 190 , Thereby, a flow of hydraulic fluid from a pump chamber 350 in the blind hole 280 prevented. A flow of hydraulic fluid in the reverse direction is possible when the pressure in the blind hole 280 hydraulic fluid is large enough, the ball 340 against the force of the spring 330 and in the pump chamber 350 prevailing pressure from the valve seat 190.2 withdraw. As indicated above, pushes the spring 170 the ball 180 against the valve seat 210.2 of the second bushing part 210 , whereby a flow of hydraulic fluid from the chamber 340 in the direction of the high-pressure channel 140 allows, but in the opposite direction is prevented.

At one through the eccentric arrangement 500 initiated movement of the piston 190 to the right is a in the pump chamber 350 located hydraulic fluid in the direction of the high-pressure channel 140 pushed out. Allows the eccentric arrangement 500 a movement of the piston 190 To the left, this is due to the force of the spring 320 in contact with the eccentric arrangement 500 held and moves to the left. Hydraulic fluid flows from the low pressure channel 130 through the filter element 270 in the cross hole 290 of the piston, and from there on through the blind hole 280 in the pump chamber 350 , Subsequently, the eccentric arrangement moves 500 the piston back to the right and a new pump stroke begins.

By arranging the bushing parts 200. and 210 It is possible to mount the first bushing part 200. in the piston pump housing 110 required axial forces when inserting the piston pump subassembly 120 in the piston pump housing 110 from the right by the second bushing part 210 is pressed to the left. In one embodiment, in the same operation, the valve subassembly 150 into the piston pump housing 110 be inserted by applying a leftward force to the valve subassembly 150 this is partially applied to the valve subassembly 120 is passed on. In this case is for the assembly of the entire piston pump subassembly 120 and the valve subassembly 150 in the piston pump housing 120 only a single press-in required.

This type of mounting can be used in the production of the piston pump 100 By saving work steps considerable costs can be saved. In addition to conventional piston pumps, which require pressing individual sealing or support rings in a piston pump housing before a piston pump subassembly is used, there is the additional advantage that tilting of elements to be pressed in that the piston pump subassembly 120 is preassembled, and by action of the shoulders and cones 110.1 to 110.4 the piston pump housing is practically excluded.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19732817 A1 [0004, 0007]
• DE 10015295 A1 [0007]

Claims (16)

Piston Pump Subassembly ( 120 ), with a. a piston ( 190 ); b. one the piston ( 190 ) axially displaceable receiving and the piston ( 190 ) at least partially bearing liner ( 200. . 210 ), with the liner ( 200. . 210 ) has an end opening in order to prevent an interaction of the piston with a drive element ( 500 ); and c. one in the bush ( 200. . 210 ) sealing between the piston ( 190 ) and the liner ( 200. . 210 ) received first sealing element ( 220 ), which is arranged to the passage of a medium to be conveyed from the frontal opening of the liner ( 200. . 210 ) to the drive element ( 500 ) counteract. Piston Pump Subassembly ( 120 ) according to the preceding claim, characterized in that the first sealing element ( 220 ) substantially stationary with respect to the liner ( 200. . 210 ) is fixed. Piston Pump Subassembly ( 120 ) according to claim 2, characterized in that the first sealing element ( 220 ) at one in the liner ( 200. . 210 ) trained shoulder ( 200.1 ) is supported. Piston Pump Subassembly ( 120 ) according to one of claims 2 or 3, characterized in that the first sealing element ( 220 ) on one at the bushing ( 200. . 210 ) fixed fixing element ( 240 ) is supported. Piston Pump Subassembly ( 120 ) according to one of the preceding claims, characterized in that the first sealing element ( 220 ) near a drive element ( 500 ) facing end face of the liner ( 200. . 210 ) is arranged. Piston Pump Subassembly ( 120 ) according to one of the preceding claims, characterized in that between the piston ( 190 ) and the liner ( 200. . 210 ) a second sealing element ( 300 ) is provided to a transfer of the medium to be pumped between the piston ( 190 ) and the liner ( 200. . 210 ) from a medium inlet to a medium outlet of the liner ( 200. . 210 ) or vice versa. Piston Pump Subassembly ( 120 ) according to the preceding claim, characterized in that the second sealing element ( 300 ) near a drive element ( 500 ) facing away from the end face of the piston is arranged. Piston Pump Subassembly ( 120 ) according to one of the preceding claims, characterized in that the bushing ( 200. . 210 ) is constructed in two or more parts, wherein the piston ( 190 ) in at least two of the bushing parts ( 200. . 210 ) is stored. Piston Pump Subassembly ( 120 ) according to the preceding claim, characterized in that between at least two adjacent bushing parts ( 200. . 210 ) at least one connecting element ( 260 ) is arranged. Piston Pump Subassembly ( 120 ) according to one of the preceding claims, characterized in that at least one filter element ( 270 ) is present in order to remove impurities in one of the piston pump ( 100 ) to retain the medium to be promoted. Piston Pump Subassembly ( 120 ) according to claims 8 to 10, characterized in that the at least one connecting element ( 260 ) the at least one filter element ( 270 ) comprises or fixes. Piston Pump Subassembly ( 120 ) according to one of the preceding claims, characterized in that the first sealing element ( 220 ) a frictional force on the piston ( 190 ), which is a falling out of the piston ( 190 ) from the liner ( 200. . 210 ) counteracts. Piston Pump Subassembly ( 120 ) according to one of the preceding claims, characterized in that the first sealing element ( 220 ) is designed in the form of a quad-ring. Method for mounting a piston pump subassembly ( 120 ) according to one of claims 1 to 13, comprising the step of mounting the preassembled piston pump subassembly ( 120 ) in a piston pump housing ( 110 ). Piston pump comprising a piston pump housing ( 110 ) and at least one, in the piston pump housing ( 110 ) received piston pump subassembly ( 120 ) according to one of claims 1 to 13. Piston pump according to claim 15, characterized in that the piston pump subassembly ( 120 ) on at least one shoulder ( 110.3 . 110.4 ) and / or at least one cone ( 110.1 . 110.2 ) in the piston pump housing ( 110 ) formed bore for the piston pump subassembly ( 120 ) is supported.