JP2015501399A - Tubular filter for vehicle brake system piston pump - Google Patents

Abstract

Tubular of a piston pump (10) for a vehicle brake device having an annular area (46) for surrounding the slidable piston (14) in axial alignment with a seal ring (26) also surrounding the piston (14). According to the invention, the filter (40) has a passage (48) for guiding at least one fluid to the section (46) from the side facing away from the seal ring (26) of the section (46). To the side of the zone (46) facing the seal ring (26). [Selection] Figure 3

Description

  The invention relates to a tubular filter of a piston pump for a vehicle brake device, having an annular area for surrounding a slidable piston, axially aligned with a seal ring also surrounding the piston. The invention further relates to the use of such a tubular filter in a pump member of a piston pump for a vehicle brake device.

  Filters are used to ensure that dirt particles are not carried to the associated intake and discharge valves, particularly in the piston pumps of hydraulic systems in vehicle brake devices. Dirt particles can negatively affect the closing behavior of the valve, and can lead to permanent damage to the attached valve seat and closure.

  There is a seal ring for the piston in axial alignment with the tubular filter of this kind of piston pump. In addition to its filtering function, the filter additionally has the function of guiding it to the target position when assembling the seal ring and keeping it there with reliable operability. However, in known piston pumps for vehicle brake devices, problems such as insufficient positioning and increased wear occur partially in the seal ring.

  A piston pump comprising such a type of filter is known from US Pat. The filter of this document is formed in a tubular shape and surrounds an attached piston. The positioning of the seal ring is solved in this piston pump by the fact that the filter additionally has a guide ring and a seal ring for the piston.

German Patent Application Publication No. 19902019A1

  It is an object of the present invention to provide a vehicle brake device with a piston pump that allows the seal ring to be correctly positioned with the filter during assembly and at the same time remains accurately positioned during operation. is there.

  According to the present invention, there is provided a tubular filter of a piston pump for a vehicle brake device, having an annular area for surrounding a slidable piston, axially aligned with a seal ring also surrounding the piston, said area comprising at least One fluid guiding passage is provided from the side of the zone facing away from the seal ring to the side of the zone facing the seal ring.

  The knowledge on which the present invention relies is that the filter may be deformed by inserting the piston together with the filter and the seal ring when assembling the piston pump for the vehicle brake device. Such a deformation can lead to a situation where the clearance normally provided between the area of the filter surrounding the piston and the piston itself is reduced to a minimum. The filter is then substantially abutted against the piston by its annular area during operation of the piston pump, so that wetting of the piston by brake fluid under said area is reduced. In part, the zone may act like a scraper and even prevent the formation of a liquid film at the piston.

  This loss of piston wetting can result in significant wear, mispositioning, and possibly even ignition of the side-by-side seal rings. In contrast, the solution according to the invention ensures a regular and good flow of brake fluid into the seal ring. The dry operation of the seal ring is reliably prevented. This ensures that the seal ring remains correctly positioned throughout its useful life and maintains its sealing action. The eye of the present invention provides at least one passage for the filter in the area surrounding the piston facing the seal ring, which ensures that the brake fluid passes through the area and reaches the seal ring. There is something you can do. The passage part is configured to remain fluid-permeable by itself, especially when the filter is deformed due to assembly. This kind of at least one passage according to the invention ensures the lubrication of the seal ring even at low temperatures and when the brake fluid has a low viscosity.

  The at least one fluid guiding passage is preferably configured as a groove facing the piston in the annular section. In such a region of the groove, it is ensured that a fluid guiding connection is maintained through the area surrounding the piston, and furthermore, no brake fluid is scraped off from the piston in the region of the groove. In this way, the fluid film of the piston is reliably maintained in the region of the groove during operation and during piston movement in the associated filter.

  It is particularly preferred that a plurality of grooves are arranged, particularly regularly spaced, on the inner circumference of the annular area surrounding the piston. With the plurality of grooves, the effect obtained according to the present invention can be realized by being distributed over the entire circumference of the piston.

  The passage part for guiding at least one fluid is preferably produced by injection molding together with a tubular filter. With such a manufacturing method, a plurality of passage portions can be manufactured in the filter according to the present invention without substantially changing the cost. Furthermore, the injection molding process has the advantage that it can be used to mold one or more metal filter sheaves together in a filter.

  Furthermore, it is preferred that the at least one fluid guiding passage is configured to have a sectionally rectangular cross-sectional shape. This kind of shape gives rise to a preferred opening cross-sectional area of the passage part at the same time, in particular due to the high stability and shape stability of the filter when assembled with the seal ring in the housing surrounding the piston on the outside.

  The solution according to the invention further comprises the use of such a tubular filter according to the invention in a pump member of a piston pump for a vehicle brake device for supplying lubricating brake fluid to a seal ring. Yes.

  Embodiments of the solution according to the invention will now be described in detail with reference to the attached schematic drawings. The drawing shows the following:

FIG. 3 is a partial longitudinal sectional view showing a piston pump according to the prior art having a filter disposed therein and a seal ring provided alongside the filter; It is a perspective view which shows the filter of FIG. It is a perspective view which shows the Example of the filter by this invention.

  FIG. 1 partially shows a piston pump 10 in which a piston 14 is slidably supported in a cylinder 12. The piston 14 can be mechanically driven by an eccentric (not shown) on the right side in FIG.

  A take-in line 16 passes radially through the cylinder 12 to a take-in passage 18 formed in the piston 14. The inflowing liquid, in this example, the brake fluid, reaches the pressure chamber 22 through the intake valve 20 from here. That is, the pressure chamber 22 is on the left side of the piston 14 as viewed in FIG. When the piston 14 moves, the pressure chamber 22 narrows, whereby fluid is pushed out of the cylinder 12 under pressure through a discharge valve (not shown).

  The piston 14 is surrounded radially by a filter 24 which serves to filter the fluid supplied through the intake line 16 and dirt particles reach the intake valve 20 and the discharge valve. To prevent. A seal ring 26, a support ring 28, and a guide ring 30 are arranged on the filter 24 in the axial direction and on the right side as viewed in FIG. The seal structure thus configured is held in the housing 32 to prevent fluid from reaching the eccentric side from the intake line 16.

  The filter 24 is constituted by a tubular body 34 which is injection-molded from plastic and in which a plurality of metal filter lattices 36 are cast and arranged circumferentially in the region of the intake line 16. The metal filter grating 36 is a fine fabric made of very thin metal lines.

  The filter 24 is configured with an annular section 38 on the side facing the seal ring 26 that surrounds the piston 14 in its entire circumference. The inner circumference of the annular section 38 is circular and is configured with a diameter that is slightly larger than the diameter of the piston 14.

  FIG. 3 shows a filter 40 according to the present invention, also configured to have a tubular body 42 and a plurality of filter grids 44 disposed therein. The body 42 is substantially the same configuration as the body 34 in terms of its outer dimensions, but its inner circumference is not circular in the annular section 46.

  Rather, the section 46 of the filter 40 has a groove 48 with a generally rectangular cross section extending axially over the entire area 46 on its inner circumference. The groove 48 serves as a fluid guiding passage, even when the annular section 46 surrounds the piston 14 in other locations, for example, almost liquid tightly due to deformation or thermal expansion. It is ensured that the adjacent seal ring 26 receives a sufficient supply of lubricating fluid for lubrication. In an embodiment not shown, such a plurality of grooves 48 are evenly spaced from one another over the inner circumference of the section 46.

DESCRIPTION OF SYMBOLS 10 Piston pump 14 Piston 26 Seal ring 40 Filter 46 Annular area 48 Passing part

Claims (6)

Tubular of a piston pump (10) for a vehicle brake device having an annular area (46) for surrounding the slidable piston (14) in axial alignment with a seal ring (26) also surrounding the piston (14). In the filter (40):
The section (46) has at least one fluid guiding passage (48) facing away from the seal ring (26) of the section (46) from the side of the seal ring (46) of the seal ring (46). 26) A tubular filter, characterized in that it is provided on the side facing towards 26).   Tubular according to claim 1, characterized in that said passage (48) for fluid guidance is configured as a groove (48) facing the piston (14) in the annular section (46). filter.   3. Tubular filter according to claim 1 or 2, characterized in that a plurality of grooves (48) are arranged at regular intervals in the inner circumference surrounding the piston of the annular section (46). .   The tubular filter according to any one of claims 1 to 3, characterized in that the passage (48) for fluid guidance is produced by injection molding together with the tubular filter (40).   The tubular filter according to any one of claims 1 to 4, characterized in that the passage (48) for fluid guidance is configured to have a sectionally rectangular cross-sectional shape.   Use of a tubular filter (40) according to any one of claims 1 to 5 in a pump member of a piston pump (10) for a vehicle brake device, wherein the brake fluid to be lubricated is sealed with a seal ring (26). Usage to supply to.

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