KR20150056056A - Block-shaped hausing of a hydraulic unit of a vehicle brake system - Google Patents

Abstract

A block-type housing (30) of a hydraulic unit of a vehicle braking system separated from a rod-shaped extrusion press profile (10) by a separation process, wherein the block-like housing (30) is provided with two opposed separating surfaces ) Is formed in the block-like housing, at least one of the separation surfaces (32, 34) is provided with an anode coating (44).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a block-shaped housing of a hydraulic unit of a vehicle brake system,

The present invention relates to a block-like housing of a hydraulic unit of a vehicle brake system separated from a rod-shaped extrusion press profile by a separating process, wherein the block-like housing is formed with two opposed separating surfaces. The present invention also relates to a method of manufacturing the block-type housing.

The hydraulic unit is used to provide controlled brake pressure to the brake system in an automobile, for example a passenger car or a freight car. Accordingly, the functions of the ABS system and / or the ESP system are implemented in particular. To this end, the hydraulic unit generally comprises a pump with a plurality of pump pistons, a plurality of electromagnetically controlled valves, a control device for controlling the valve, and a motor for moving the pump piston. In this case, the pump pistons are housed in a block-like housing or a so-called hydraulic block, which is disclosed, for example, in DE 10 2009 026 417 A1 and DE 10 2010 062 270 A1 in addition to the corresponding production method.

The individual block-type housings or pump housings are conventionally formed of aluminum. In addition, the control device and the corresponding motor are disposed in one interface on the pump housing. The control device and the motor are generally formed of iron or iron containing material and must at least include a protective layer that functions as a passivation for the interface or prevents corrosion or should be formed of stainless steel. Otherwise, contact corrosion occurs between the aluminum and the iron due to electrochemical heat, and the contact corrosion especially causes a so-called formula in the pump housing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a block-shaped housing having a high-quality corrosion-resistant separating surface and a method of manufacturing the housing.

This object is achieved by a block-like housing according to claim 1 and a manufacturing method according to claim 6.

According to the present invention there is provided a block-type housing of a hydraulic unit of a vehicle braking system separated from a rod-shaped extrusion press profile by a separating process, wherein the block-type housing is formed with a block- do. In this case, at least one of the separating surfaces includes an anode coating.

A positive electrode film means a layer, especially made of an aluminum oxide in the electrolyte and, Eloxal is an abbreviation for el ectrolytic Ox idation von Al uminium. The aluminum oxidized by the electrolyte is formed by electrolytic conversion of the top metal layer with aluminum to the block-shaped housing into an oxide or hydroxide, preferably by anodic oxidation. The aluminum- (III) -oxide (Al ₂ O ₃ ) formed by the terminal process by the oxidation process is not provided as a layer but acts as a particularly stable oxidation protection layer by being formed by oxidation of the uppermost aluminum layer. This oxidation protection layer protects the deeper layers of aluminum from corrosion, as long as there is no gap in the oxidation protection layer. These oxidation protective layers or anodic coatings are also extremely hard (approximately Mohs hardness 9) and are corrosion resistant and form correspondingly hard and corrosion resistant separating surfaces of very high quality.

The block-like housing or pump housing itself according to the invention is used as a functional part in the hydraulic unit, in particular for accommodating at least one pump piston and a motor shaft for moving the at least one pump piston.

According to the present invention, preferably at least one separating surface with an anodic coating is formed as a connecting surface for connecting additional functional components of the hydraulic unit, in particular a motor and / or control device. Thus, additional functional parts of the hydraulic unit can be connected or arranged on the separating surface itself. When arranged in this way, the anodic coating on the separating surface forms a particularly corrosion-resistant connection surface or interface for the additional functional part, and there is no risk of connection corrosion. Contact corrosion is due to different standard electrode potentials in the electrochemical column of different materials of the relevant part. In particular, aluminum (Al ^{3 +} / Al) having a standard potential E ° of -1.66 V is particularly negative, and therefore can be used with most other commonly used materials, such as iron with a standard potential E ° of -0.04 V Fe ^{3 +} / Fe), and alloys thereof. Acoustic properties mean that aluminum here pushes to release electrons as other contacted materials such as iron. When a functional component made of iron is placed in a block-like housing with aluminum, the aluminum releases electrons to the iron, and contact corrosion, especially so-called formulas, appears. As a result, moisture can penetrate into the hydraulic block, which can cause a failure of the entire hydraulic unit and thus the failure of the entire brake system.

Conventional interfaces have been formed to be protected from such contact corrosion by use of expensive, passivating coatings, for example aluminum with zinc-nickel alloy or by use of expensive stainless steel. These measures are implemented as secondary measures and generally in additional functional components. Compared to this interface manufactured in a conventional manner, the separating surface according to the invention in the block-shaped housing has the advantage that the block-shaped housing is itself passivated thereat by the anode coating. Thus, at least one protective layer is formed inexpensively and without additional material consumption in the block-like housing itself, and the protective layer is particularly corrosion-resistant.

The invention also applies to a hydraulic unit for a vehicle braking system comprising a block-like housing according to the invention as a functional part and at least one additional functional part connected thereto. The at least one additional functional component is preferably a motor and / or control device here.

The rod-shaped extrusion press profile is produced by an extrusion press method, in particular by extrusion method, and the separated block-shaped housing is formed from aluminum on at least one parting surface. Particularly preferably, the entire rod-shaped extrusion press profile and therefore the entire block-like housing is made of aluminum in particular in view of the manufacturing technique. When formed of aluminum in this manner, the block-like housing can be formed as an anode coating according to the present invention on at least one separating surface.

According to the invention, the anodic coating is preferably formed by a separating process which separates the block-like housing from the rod-shaped extrusion press profile, in particular by a wire discharge machining method. Since this anodic coating is simultaneously at least one separating surface, the block-like housing is separated from the extrusion press profile in one step in a cost-saving manner and corrosion protection measures are provided on at least one separating surface. Particularly, the anode coating is formed by the wire electric discharge machining method, so that a particularly well-formed, block-shaped housing is formed, and its shape and surface need not be further processed. Also, the surface has already been passivated by itself.

The wire discharge machining method is a highly accurate method of cutting a conductive material, which is based on an electric discharge process between the electrode and the conductive workpiece as a tool in general. Electric discharge processes are also called sparks, and the method is also called arc discharge or arc discharge machining. During arc discharge cutting, the machined wire is guided through the workpiece as an electrode, and the workpiece is placed in a non-conductive medium, a so-called dielectric. In this case, an arc is generated by the voltage pulse, and the material of the workpiece is transferred to the discharge machining wire and the dielectric. Very high cutting accuracy is achieved because the individual arcs always skip exactly at the point where the gap between the workpiece and the machining wire is minimal. In this case, the arc melts and evaporates the material of the workpiece in a point shape. Depending on the intensity, frequency, duration, length, gap width and polarity of the discharge, different removal results appear. Generally, the tool is provided with a positive charge and the workpiece is provided with a negative charge. Thus, electron transfer, in this case the transfer of charge of the workpiece in the direction of the discharge machining wire and dielectric away from the workpiece, is shown so that material removal takes place in the workpiece.

In the preferred wire discharge machining method according to the present invention, preferably a rod-shaped extrusion press profile with aluminum is used as the workpiece, and deionized water is particularly preferably used as the dielectric. Therefore, at the time of cutting the extruded press profile with the electric discharge machining wire or when separating the block-type housing, the aluminum oxide layer or the anode coating is simultaneously formed on the separation face of the housing which is in contact with the both sides. The individual separation surfaces formed in this manner are particularly flat and precisely formed.

In addition, the anode coating is formed according to the present invention preferably in a layer thickness of 1 micrometer to 16 micrometers, especially 2 micrometers to 8 micrometers. Thus, a very low corrosion resistance as well as a very low layer thickness are formed. With this low layer thickness, the material for the anode coating is very little consumed in the block-like housing formed together and can be used for additional functions, for example, for accommodating a piston pump. In particular, a block-type housing of a space saving type is formed as a whole.

In addition, the individual separating surfaces preferably have a uniformly rough surface structure according to the present invention, but have a surface structure without continuous rill or marks. Such a separating surface can be sealed with a particularly small sealing width, in particular as an interface to the additional functional parts. In comparison, the conventional interface has continuous fine marks on its surface due to manufacturing. These marks are formed during the manufacturing process by forming the conventional interface directly on the extrusion surface formed in the hydraulic block by the milling process or in the production of the extrusion press profile. These marks are difficult to seal with great expense because the sealant must be fully inserted into the individual marks to prevent penetration of the sealant through the marks. To this end, a sealant with a correspondingly large sealing width is required, which determines the width of the block-like housing.

According to the invention, if the at least one separating surface according to the invention is formed with a roughness depth of preferably less than 10 micrometers, preferably less than 9 micrometers, particularly preferably less than 8 micrometers, Width is achieved. In this case, the depth of roughness is a measure of the roughness and hence the unevenness of the surface of the individual separating surfaces. The depth of roughness is in particular the difference between the maximum and minimum of the width of the surface perpendicular to the plane of the separation surface. Preferably, the depth of roughness is measured at a plurality of points on the surface to obtain an average value R _z , the average roughness depth. Due to the depth of the roughness according to the invention, the individual separating surfaces have a particularly coarse surface structure. Thus, such a separating surface has a very large adhering surface, and additional parts, in particular functional parts, can be adhered on the adhering surface with particularly high adhesive strength. Preferably, for this purpose, the depth of the roughness has a minimum size of 3 micrometers, particularly preferably 5 micrometers. In this manner, the adhesive agent used for bonding can be gathered in the groove thus formed, and a stable bonding effect can be exhibited.

Also, the two separate facing surfaces of the block-like housing, according to the invention, are preferably formed with a separation tolerance of less than 0.10 millimeter, preferably less than 0.03 millimeter. The separation tolerance is the difference between the minimum and maximum spacing between two opposing separation surfaces. Particularly small separation tolerances in accordance with the present invention mean that the two opposing separation surfaces are placed approximately parallel to each other. Thus, the separation surfaces are formed very accurately, which facilitates further assembly of the block-like housing within the hydraulic unit. If two separate faces are used as the functional plane for each one interface to the controller and the motor, very high accuracy of the functional planes is ensured.

Furthermore, at least one separating surface is preferably produced according to the invention without burrs. The burr-free separating surface forms the most possible effective surface as a connecting surface in the block-like housing, which can be used for connection or mounting of additional parts, in particular functional parts, and / or for sealing purposes. Also, there is no protruding burr at risk of injury.

Furthermore, since at least one separating surface is preferably formed flat according to the present invention, it provides a very large effective surface as a connecting surface for connecting additional parts, in particular functional parts.

The present invention also relates to a method of preparing a rod-shaped extrusion press profile, And a separating step of separating at least one block-shaped housing from the rod-shaped extrusion press profile by a separating process, wherein the separating step uses a wire electric discharge machining method as the separating step. Type housings. With the above-described wire discharge machining method, since the accuracy is used to manufacture the block-shaped housing according to the present invention, the housing can be formed very accurately without any additional method steps that are conventionally required. At the same time, much less material of the rod-shaped extrusion press profile is consumed by the discharge machining wire during the separation process than with conventional separation methods, such as sawing. The sawing blade used in sawing generally has a thickness of about 3 millimeters, while the discharge machining wire used in accordance with the present invention preferably has a diameter of only about 0.2 millimeters.

According to the present invention, preferably, in the wire electric discharge machining method, at the same time, the anode coating is formed on at least one of the separation faces of the block-shaped housing. That is, in one step, the precise, block-shaped housing is separated from the extrusion press profile, and at least one of the separating surfaces is provided with a passivation or corrosion-resistant anode coating. Thus, time and materials are saved, and particularly short cycle times are achieved in industrial manufacturing processes.

In addition, the anode coating is formed according to the present invention preferably in a layer thickness of 1 micrometer to 16 micrometers, especially 2 micrometers to 8 micrometers. This low layer thickness can be formed very quickly and simultaneously at the same time by the wire electric discharge machining method according to the present invention.

It is also preferred in accordance with the invention in the wire discharge machining that at least one of the separation surfaces of the block-shaped housing has a roughness depth of less than 10 micrometers, preferably less than 9 micrometers, particularly preferably less than 8 micrometers, and / RTI > This depth of roughness can be manufactured very simply by means of the precise wire electrical discharge machining process, and the additional parts form individual separation surfaces which can be very simply attached, in particular glued and sealed. Particularly preferably, the individual separation surfaces are produced in the separation process according to the invention, in particular without a burr in the wire discharge processing process. Therefore, it is possible to omit later burr removal, which was necessary for the conventional separation method, and thus, a very short cycle time can be realized in the manufacture of the block-shaped housing according to the present invention.

Also, the two opposing separating surfaces in the block-like housing are preferably formed according to the invention with the aforementioned separation tolerances of less than 0.10 millimeters, preferably less than 0.03 millimeters. In this case, the two opposing separation surfaces can be used immediately as a motor interface and controller interface or as a solenoid valve interface (MV-interface). The two separation surfaces, including the solenoid valve, together with the seal form a side with which the motor can be attached with the control device and seal. Thus, in the manner of work and cost saving in particular, the later and other necessary plane and / or cutting of the block-like housing is omitted.

According to the present invention, preferably, also in the wire electric discharge machining method, a plurality of block-shaped housings are simultaneously cut from the rod-shaped extrusion press profile. The wire discharge machining method may be a so-called multi-cut method in which the rod-shaped extrusion press profile is cut at one point by a wire or an electric discharge machining wire or electrode which is a separating means at a plurality of points at the same time. Thus, block-type housings can be produced in large quantities very quickly and economically. If separating means, especially low-loss separating means, is used, the economical efficiency is preferably higher.

According to the present invention, there is provided a block-shaped housing having a high-quality corrosion-resistant separating surface and a method of manufacturing the housing.

Hereinafter, an embodiment of a solution according to the present invention will be described in detail with reference to the accompanying schematic drawings.

1 is a perspective view of a rod-shaped extrusion press profile according to the prior art and a block-like housing separated therefrom.
Figure 2 is a perspective view of the block-like housing according to Figure 1;
Figure 3 is an enlarged view of part III of Figure 2;
4 is a perspective view of one embodiment of a rod-shaped extrusion press profile and a plurality of block-shaped housings separated therefrom according to the present invention.
Figure 5 is a perspective view of the block-like housing according to Figure 4;
6 is an enlarged view of a portion VI of Fig. 5; Fig.

Figure 1 shows a rod-shaped extrusion press profile 10 with aluminum obtained from an aluminum strand by means of an extruder not shown, either by extrusion or extrusion. The blocks 12 are sacked perpendicular to the extrusion press direction 11 from the rod-shaped extrusion press profile 10. The block 12 is used as the base body of the block-like housing. As a result, the first rising surface 14 and the opposing second rising surface 16 are formed. The sawing surfaces together with the first extruding surface 18, the second extruding surface 20, the third extruding surface 22 and the fourth extruding surface 24 form a rectangular block 12. Further, on the extruding surfaces 18 to 24, burrs 25 are formed on the sides thereof, and the burrs must be removed in the subsequent method steps. Sawing surfaces 14 and 16 and extrusion surfaces 18 to 24 are all formed of aluminum as the interface of block 12 (Figure 2).

The block 12 is assembled in a hydraulic unit of the vehicle brake system, not shown, as a functional part in a subsequent method step, after the additional machining step as a block-like housing. To this end, two opposing extruded surfaces are required as connection surfaces or interfaces for later connection of additional functional components. Here, the extrusion surface 18 is used as an interface for the motor 26 and the extrusion surface 22 is used as an interface for the control device 27. [ The two extruding surfaces 18 and 22 include a surface that uniformly has a continuous rill (so-called tool mark 28), which is caused by processing during extrusion (Fig. 3). The successive tool marks 28 should be sealed with a sealing width that allows the sealant to be fully inserted into the tool mark 28 upon mounting of the motor 28 and controller 27, respectively. Therefore, penetration of the sealant through the tool mark 28, so-called seal penetration, must be prevented.

Block 12 also includes a manufacturing rounded edge having a radius 29 between extrusion surfaces 18,20, 22,24. The radius 29 is determined by the die of an extruder having a nearly rectangular cross section, which is used in the extrusion process, and the edge of the cross section is rounded to a radius 29. [ By means of such a die, the aluminum strand is pressed and / or drawn so that the rod-shaped extrusion press profile 10 always has a rounded edge with a radius 29. The radius 29 or the drawing radius determines the size of the face as an interface for mounting additional components, in particular functional components, which can be used in the first extrusion surface 18 and the third extrusion surface 22. The larger the radius 29, the less flat surface can be used as the interface undesirably. For this disadvantage, there is an advantage that a correspondingly long tool life is achieved by a relatively large radius 29 on the purely manufacturing technology.

Further, the motor 26 and the control device 27 are made of iron or iron-containing material in particular. The surfaces of the engine 26 and the control device 27 are coated with a passivated protective layer, for example a zinc-nickel alloy. Thus, contact corrosion of the aluminum of the block-like housing or block 12 is prevented in a conventional manner at a relatively high cost.

4 to 6, a rod-shaped extrusion press profile 10 made of aluminum is extruded aluminum strands which are separated by the separation process according to the invention. As a material, AlMg ₃ MnSi ₄ is used as an aluminum alloy. As a separation method, a multi-cut method of wire electric discharge machining is carried out here, and a plurality of discharge machining wires are wound as a tool (not shown) through the rod-shaped extrusion press profile 10 perpendicular to the extrusion press direction 11 Guidance. In this case, a plurality of blocks or block-shaped housings 30 are simultaneously cut with high accuracy. At the time of cutting, two separating surfaces 32 and 34 are formed on both sides of the penetrating tool, and the separating surfaces are formed with burrs and uniformly rough surfaces. The two opposed separating surfaces 32 and 34 comprise four extruded surfaces 36, 38, 40 and 42, respectively, in the individual block-like housing 30, and the extruded surfaces have no burrs . This eliminates the need for complicated deburring.

Between the extrusion surfaces 36, 38, 40, and 42, a radiused edge 43 is created, which occurs in the extrusion process as described above. However, in the solution according to the invention, the radius 43 has an influence on the surface as an interface used for the mounting of additional functional components only with a small enough size to be negligible compared to the block 12 manufactured in the conventional manner It goes crazy. As an interface or connection surface, at least one of the two separation surfaces 32 and / or 34 is provided in accordance with the present invention, and the edge of the separation surface is rounded to a radius 43. Thus, by the separation surfaces 32 or 34 when the external dimensions are the same, as the interface, which is larger than the conventional block 12 with edges each rounded at two opposing sides on the extrusion surface 18 or 22, A block-shaped housing 30 having an effective surface is formed. When rounded in this manner, the surface therein is not provided as a substantially planar effective surface (FIG. 5 vs. FIG. 2). As such, the edges of the separation surfaces 32, 34 can have a larger radius 43 than would be the case with the known radius 29 without damage. This larger radius 43 achieves a longer tool life in a cost saving manner in the extrusion process.

The radius 43 lies differently than the conventional radius 29 with respect to the individual interface. This is because the extrusion press direction 11 or the extrusion direction is changed in comparison with the conventional block 12 with respect to the individual interface. In the conventional manner, the extrusion press direction 11 extends parallel to the individual interface formed by the extrusion surface 18 or 22. According to the invention, the extrusion press direction 11 extends perpendicular to the individual interface formed by the separating surface 32 or 34. The extrusion press direction 11 thus changed is made possible by the wire electric discharge machining method according to the present invention. Thus, burr-free split faces 32 and 34 are formed and these split faces can be immediately used as an interface without further burr removal and additional surface treatment.

The two separating surfaces 32 and 34 are formed in the separating process so as to have one anode coating 44 on each side of the tool already having a layer thickness 46 of 2 to 8 micrometers. The anode coating 44 thus formed is produced as an aluminum- (III) -oxide (Al ₂ O ₃ ) by electrochemical conversion from the uppermost aluminum layer of the extrusion press profile 10, and is not provided as a layer. Therefore, the anode coating 44 is very firmly bonded to the aluminum of the block-shaped housing 30 and forms a reliable protection of aluminum against corrosion, in particular against contact corrosion described above. Thus, the motor 26 and the control device 27 are mounted as additional functional components in each one of the separation faces 32 and 34 by the block-like housing 30 according to the invention, Parts need not be protected from contact corrosion at high cost.

The uniformly roughened surface of the anodic coating 44 according to the present invention has a roughness depth R _Z (48) of less than 10 micrometers, on the average of about 7.1 micrometers. In addition, there is no systematic pattern of processing, for example, in the form of a continuous reel or mark. Due to the roughness depth 48 and the absence of a continuous mark, a further part, in particular a parting surface 32 or 34, is formed in which the functional part can be arranged and sealed with very simple and small sealing widths. It is particularly preferred that the additional parts can be glued with a high adhesive force simply because the corresponding, cohesive glues used can be gathered in the roughness depth 48. [

At the same time, the separating surfaces 32 and 34 face each other at approximately equal intervals or in parallel, since they are formed with very high dimensional accuracy and therefore with a very small separation tolerance of about 0.03 millimeters. The anodic coating 44 of the separation surfaces 32 and 34 is therefore intended to be used as a functioning surface or interface which is precisely formed for connection of the motor 26 and the control device 27 of the hydraulic unit. To this end, the interface of the control device is formed on the motor side without reference machining, so that further cutting is omitted in the material and time saving manner.

In the embodiment not shown, the rod-shaped extrusion press profile 10 has a square cross-section and at least one disc-shaped block-like housing 30 is cut by the wire discharge machining method from the extrusion press profile. This block-like housing 30 has two square separating surfaces 32, 34, which do not require characterization for subsequent processing in a material and work-saving manner due to their square shape.

10 Extrusion Press Profile
26 Motor
27 Control device
30 Housing
32, 34 separating surface
44 anodic coating
46 layer thickness
48 Roughness Depth

Claims (10)

A block-type housing (20) of a hydraulic unit of a vehicle brake system, which is separated by a separation process from a rod-shaped extrusion press profile (10), said block-like housing (30) being provided with two opposed separating surfaces 34) are formed in the block-like housing,
Characterized in that an anode coating (44) is provided on at least one of said separating surfaces (32, 34). The method according to claim 1,
Characterized in that at least one separating surface (32, 34) is formed with an anode coating (44) as a connecting surface for connecting additional functional components of said hydraulic unit, in particular motor (26) and / or controller (27) Shaped housing. 3. The method according to claim 1 or 2,
Characterized in that the anode coating (44) is formed in a separating step of separating the block-type housing (30) from the rod-shaped extrusion press profile (10), in particular by means of a wire discharge machining method. 4. The method according to any one of claims 1 to 3,
Characterized in that the anode coating (44) is formed with a layer thickness (46) of 1 micrometer to 16 micrometers, in particular 2 micrometers to 8 micrometers. 5. The method according to any one of claims 1 to 4,
The at least one separating surface 32, 34 is formed with a roughness depth 48 of less than 10 micrometers, preferably less than 9 micrometers, particularly preferably less than 8 micrometers, and / Features a block-like housing. And a separating step of separating at least one block-like housing (30) from the rod-shaped extrusion press profile (10) by a preparation step of a rod-shaped extrusion press profile (10) In a method of manufacturing a block-shaped housing (30) of a unit,
Wherein a wire electric discharge machining method is used as said separation step. The method according to claim 6,
Wherein an anode coating (44) is formed on at least one of the separation surfaces (32, 34) of the block-shaped housing at the same time in the wire discharge machining method. 8. The method of claim 7,
Characterized in that the anode coating (44) is formed with a layer thickness (46) of 1 micrometer to 16 micrometers, in particular 2 micrometers to 8 micrometers. 9. The method according to any one of claims 6 to 8,
In the wire electric discharge machining method, at least one of the separation surfaces (32, 34) of the block-like housing (30) has a roughness depth of less than 10 micrometers, preferably less than 9 micrometers, particularly preferably less than 8 micrometers (48) and without burrs. 10. The method according to any one of claims 6 to 9,
Wherein a plurality of block-like housings (30) are simultaneously detached from the rod-shaped extrusion press profile (10) in the wire electric discharge machining method.

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