Reservoir fastening element of a hydraulic unit of a vehicle brake system and use of a reservoir fastening element

Abstract

In a reservoir fastening element (50, 152) of a hydraulic unit (12, 140) of a vehicle brake system for fastening a reservoir (38) to a hydraulic housing (10, 142), wherein the reservoir fastening element (50, 152) has a shank (106) and a shank head (104) on an axial end of the shank (106), the shank head (104) is provided with a radially inner rotary drive (126).

Description

[0001] Description

[0002] title

[0003] Reservoir fastening element of a hydraulic unit of a vehicle brake system and use of a reservoir fastening element

[0004] State of the art

[0005] The invention relates to a reservoir fastening element of a hydraulic unit of a vehicle brake system for fastening a reservoir to a hydraulic housing, wherein the reservoir fastening element has a shaft and a shaft head at one axial end of the shaft. Furthermore, the invention relates to the use of such a reservoir fastening element in a hydraulic unit of a vehicle brake system.

[0006] Conventional vehicle braking systems include hydraulic housings, which are usually designed as hydraulic blocks with various bores for receiving hydraulic components. These components form a hydraulic unit that serves to provide controlled braking pressure to the wheel brakes of a motor vehicle. Controlled braking pressures are required in control systems such as ABS, ASR, and / or ESP or FDR controls, as well as in semi-autonomous or autonomous driving. To generate braking pressure, electro-hydraulic power brake systems have a power cylinder of an electrically controllable pressure device, from which pressure medium is supplied to the wheel brakes using electrical energy during control operation. For emergency operation or a fallback mode, a master brake cylinder that is operated using muscle power is often also provided.

[0007] The required pressure medium is stored in a reservoir located on the hydraulic housing and connected to the mounts for the master brake cylinder and / or power cylinder. The reservoir is attached to one side of the hydraulic housing. Depending on the vehicle type and size, different types of brake systems with associated, sometimes different or differently sized hydraulic components are required. The components are each housed in a corresponding type of hydraulic housing depending on the vehicle brake system, its performance, and operating mode. The reservoir is then attached to the respective type of hydraulic housing, with the different types usually being different sizes. This also requires adapting the attachment of the reservoir to the hydraulic housing.

[0008] Disclosure of the invention

[0009] According to the invention, a reservoir fastening element or fastening element of a hydraulic unit of a vehicle brake system for fastening a reservoir to a hydraulic housing or housing is provided, wherein the fastening element has a shaft and a shaft head at one axial end of the shaft. The shaft head is designed with a radially inner rotary drive. The shaft head can thus be rotated in a very space-saving manner to fasten the reservoir to a reservoir side of the housing, in particular by means of a turning tool engaging in the rotary drive on its radial inner region. An otherwise required working space radially outward around the shaft head is eliminated. This enables a very space-saving fastening of the reservoir to the housing. Furthermore, the fastening element can always be rotated reliably, regardless of its external environment.This allows a uniform or customized reservoir to be attached to different types of housings using a single type of fastener. Different types of hydraulic units can thus be manufactured very cost-effectively using a single type of fastening.

[0010] According to the invention, the rotary drive is advantageously designed as a hexalobular or hexagon socket for excellent power transmission. Alternatively, the rotary drive can be designed simply as a hexagon socket.

[0011] Furthermore, according to the invention, the shaft advantageously has a cylindrical section axially opposite the shaft head and a threaded section axially located between the cylindrical section and the shaft head, which is designed with a thread. The shaft therefore has only a partial thread in a cost-effective manner, which is also arranged axially close to the shaft head. This enables particularly good force transmission when the shaft is screwed into the housing. In particular, with a self-tapping thread, such a position of the threaded section is extremely advantageous. With high force transmission, the threaded section grooves itself into a material of the housing, which is preferably made of aluminum, when the shaft is screwed in. The thread is preferably a trilobular external thread, which has a triangular cross-section as a so-called triangular round, in which a large and a small roundness are opposite each other.This ensures that the threaded section has a constant rolling diameter and is also self-locking. No additional components are required to secure the thread.

[0012] Particularly preferably, the cylindrical section is designed without a thread, thus creating a shaft region axially opposite the shaft head with a smooth outer surface. On such a cylindrical section, the fastening element for attaching the reservoir can be pushed without great resistance through an associated channel in the housing and / or an opening in the reservoir. The cylindrical section preferably has a smaller cross-sectional diameter than the threaded section. This facilitates insertion with additional play on the cylindrical section, while at the same time, the threaded section provides particular stability for the thread to be grooved into the housing material.

[0013] Furthermore, according to the invention, a stop region is advantageously provided axially between the threaded section and the shaft head. The stop region is a region with which the fastening element, after being introduced into a channel in the housing, strikes against a material of the housing and preferably against an associated step of the channel. For this purpose, the stop region is preferably designed as a ring that projects radially from the shaft largely at right angles, so that an acting stop force can be transmitted over its entire surface to the housing. Particularly preferably, the stop region is designed to be radially inclined or conical. The stop region is thus designed as a conical section or with a chamfer that narrows from the shaft head towards the threaded section. Thus, when the fastening element is mounted and in the mounted state, forces acting from the conical section are transmitted obliquely over a wide area into the housing, which is preferably designed as a block.

[0014] In particular, the shaft head has a larger cross-sectional diameter than the threaded section, and the threaded section has a larger cross-sectional diameter than the cylinder section. A stepped fastening element with three functional areas is created, each designed with sufficient material for each of its functional areas. This needs-based design saves material for the fastening element and saves installation space for a mounting in the housing and / or reservoir.

[0015] The invention further relates to the use of at least one such reservoir fastening element or fastening element in a hydraulic unit of a vehicle brake system for fastening a reservoir to a housing. In addition, the invention is also directed to a corresponding hydraulic unit with a reservoir and a housing. In this case, the housing has at least one open recess on its reservoir side facing the reservoir, which is crossed or penetrated by a channel arranged in the housing. The reservoir comprises at least one eyelet which projects from a bottom side of the reservoir facing the housing in the direction of the housing and projects into the associated open recess in the housing, and which has a through-opening aligned with the channel. In this case, the at least one fastening element is or is arranged in the channel with its shaft penetrating the respective associated through-opening.The channel has a channel opening directed towards a housing side adjacent to the reservoir side, which is adjoined by a channel section extending from the channel opening to a radially inwardly directed channel constriction. The associated fastening element is or is placed against the channel constriction with its shaft head, wherein the shaft head is designed in particular with the radially inward rotary drive. By means of the channel section and the channel constriction, a receiving space is created inside the housing, in which the individual fastening element according to the invention is or is accommodated in a space-saving manner. In particular in combination with the radially inward rotary drive of the shaft head, a particularly space-saving fastening is thus created.Preferably, the fastening element is screwed into the channel using a tool engaging the rotary drive in such a way that the threaded portion grooves into the housing material surrounding the channel. This groove is continued until the shaft head rests against the channel constriction. For this purpose, the channel constriction is preferably designed as a step and particularly preferably with a chamfer tapering into the interior of the housing, against which a correspondingly counter-shaped, conical stop area of ​​the fastening element rests.

[0016] In particular, depending on the position of the channel constriction, the channel section is designed to be axially longer or shorter. This allows the channel to be easily adapted to different types of hydraulic housing. Preferably, the housing side adjacent to the reservoir side, which has the channel opening, is a motor side of the housing, on which a motor for driving an external pressure device is to be arranged. Opposite the motor side is a control unit side, on which an electronic control unit is to be arranged. The control unit side and the motor side preferably form two wide sides of the housing, between which there are four narrow sides of a cuboid, which determine the housing thickness. One narrow side is preferably the reservoir side. The channel extends in particular along the housing thickness. The housing thickness varies depending on the type or type of hydraulic unit.Depending on the housing thickness, the channel section facing the channel opening can be adjusted in length using the channel constriction, and in particular, a position of the channel constriction adapted to the housing thickness. Preferably, a bearing section of the channel facing from the channel constriction into the housing interior is also adjustable in length. Particularly preferably, the bearing section is designed with a constant length even for different housing thicknesses, while the channel section is designed to be correspondingly longer for larger housing thicknesses. This makes it particularly easy to achieve demand-based production.

[0017] According to the invention, the shaft head is advantageously completely accommodated in the channel section. This means that the shaft head has no axial projection from the housing and can nevertheless always be reliably rotated in the channel section by means of its inventively radially inner rotary drive, regardless of the length of the channel section. Furthermore, according to the invention, the individual fastening element advantageously has a distance from a material of the housing surrounding the channel at its axial end opposite the shaft head. This means that the fastening element does not touch the housing at its axial end on the shaft. This distance creates a clearance which prevents unwanted chiseling out of the adjacent housing wall when screwing in the fastening element or during operation.

[0018] Furthermore, according to the invention, at least two connection receptacles are advantageously arranged on the reservoir side, into which a respective associated connection piece of the reservoir is or is introduced for pressure-medium-conducting contact with the housing. In particular, a blind receptacle is additionally arranged on the reservoir side, with which no pressure-medium-conducting contact can be established. Further components can be introduced into the blind receptacle. This provides additional design freedom. Preferably, a preferably bush-shaped sealing element is or is introduced into each of the connection receptacles, into which the respective associated connection piece of the reservoir is introduced radially in the center. In particular, a sealing element is also introduced into the advantageous additional blind receptacle, which is preferably designed like the aforementioned sealing element. This sealing element is then a blind sealing element that does not serve for sealing.Rather, the blind sealing element, when the reservoir is mounted on the housing, provides a surprisingly simple way to balance any forces that occur. The blind sealing element and the two sealing elements from the reservoir to the housing are preloaded. This preload at three points on the reservoir side prevents unwanted tilting of the reservoir.

[0019] This enables a relatively uniform design of the reservoir side while simultaneously meeting different requirements for an associated braking system. If required, two connection receptacles on the reservoir side are advantageously arranged in a line parallel to the adjacent housing side or along a longitudinal extent of the reservoir side. The blind receptacle is preferably arranged deviating from this line, in particular such that an imaginary triangle is formed by the centers of the two connection receptacles and the blind receptacle. Any clamping and compressive forces arising from all sealing elements, the reservoir and the housing are then distributed particularly evenly. The reservoir is preferably attached with just one fastening element and just one associated channel between the two connection receptacles in a way that saves components and installation space. In particular, the distance between the two connection receptacles and the channel is designed to be the same.Preferably, the reservoir comprises two eyelets, each of which is received in an open recess on the reservoir side in a fastening line and penetrated by a single fastening element.

[0020] Such a requirement is met, for example, by a braking system with two spatially separated units or blocks. A first unit, as the actuation unit, comprises elements for generating brake pressure, and a second unit, as the modulation unit, comprises elements for regulating or modulating the generated brake pressure. The elements of the actuation unit are arranged in a housing to which the reservoir is coupled as described. In particular, the reservoir has two pressure-medium-separated chambers, each of which is connected to a connection receptacle. Such a braking system is also referred to as a two-box system or Decoupled Power Brake (DPB).

[0021] Furthermore, according to the invention, a first, second and third connection receptacle are advantageously arranged on the reservoir side, into each of which a corresponding connection piece of the reservoir is introduced for pressure-medium-conducting contact with the housing. The third connection receptacle connects an external power cylinder receptacle to an associated third connection piece of the reservoir and is arranged on the reservoir side, in particular between the first and second connection receptacles. The first and second connection receptacles are preferably arranged along the longitudinal extent of the reservoir side, while the third connection receptacle is arranged between the first and second connection receptacles at an offset to the longitudinal extent. This arrangement has proven to be particularly advantageous in a very compact braking system with only one unit, which comprises actuation and modulation. Such a braking system is also referred to as a one-box system orIntegrated Power Brake (IPB). The reservoir has three chambers, each of which is assigned to one of the three connection receptacles. The third chamber, assigned to the third connection receptacle, is connected to the external power cylinder receptacle and thus to the external power pressure generator via the third connection piece.

[0022] The third connection receptacle and the third chamber are preferably arranged away from a pedal side and thus, when mounted in the vehicle, away from an adjacent firewall of the vehicle. This ensures that during braking maneuvers, in which the pressure medium moves away from the firewall due to its inertia, sufficient pressure medium is available to suck the fluid into the external pressure generator or plunger. Furthermore, the third connection receptacle is arranged close to the plunger. This minimizes hydraulic resistance, which is advantageous for sucking the fluid back into the system, especially when the plunger volume is exhausted in an ABS control system.

[0023] Furthermore, two channels are advantageously provided, each accommodating a fastening element, and the three connection receptacles are arranged between the two channels. This ensures mechanical strength, particularly with sealing elements that are axially preloaded between the reservoir and the reservoir side.

[0024] The described arrangement of two or three connection receptacles is particularly preferred for a so-called regular hydraulic unit, in which a mechanical actuation area, particularly defined by a master brake cylinder, is arranged between a power cylinder and the reservoir side. A different arrangement is preferred for an inverse hydraulic unit, in which the mechanical actuation area defined by the master brake cylinder is arranged on a side of the power cylinder facing away from the reservoir side.

[0025] Furthermore, the invention is directed to a use of at least one such fastening element, in which a first type of hydraulic unit and an associated first type of housing with a first channel having a first channel section, as well as a second type of hydraulic unit and an associated second type of housing with a second channel having a second channel section are provided, and a first fastening element is received in the first channel and a second fastening element is received in the second channel. The two fastening elements are designed identically, while the two channels differ in that the second channel section has a greater axial length than the first channel section. Preferably, the different lengths of the two channel sections are the only difference between the two channels. In particular, the two different channel sections belong to different housing thicknesses of the two housings.This allows different types of housings, especially those with different housing thicknesses, to be attached to a respective reservoir using only a single type of at least one fastening element. This ensures identical attachment of the reservoir for different types of hydraulic units, each with associated housings of different thicknesses, particularly by means of the radially inner rotary drive of the shaft head. Such a modular principle, in which one fastening element serves for housings of different sizes, significantly reduces manufacturing costs.

[0026] In addition, the invention is also directed to a hydraulic unit series with at least the said first type of hydraulic unit and the said second type of hydraulic unit.

[0027] In the following, exemplary embodiments of the inventive solution are explained in more detail with reference to the attached schematic drawings. It shows:

[0028] Fig. 1 is an oblique view of a first embodiment of a hydraulic housing on which the invention is based,

[0029] Fig. 2 is a side view of an associated first embodiment of a hydraulic unit with the hydraulic housing according to Fig. 1, Fig. 3 is a housing-side oblique view of a variant of a reservoir belonging to the hydraulic unit according to Fig. 2,

[0030] Fig. 4 is a reservoir-side oblique view of the hydraulic unit according to Fig. 2 without reservoir,

[0031] Fig. 5 shows the partial section VV according to Fig. 4 with reservoir, Fig. 6 shows the partial section VI-VI according to Fig. 4 with reservoir, Fig. 7 is an oblique view of an embodiment of a reservoir fastening element according to the invention,

[0032] Fig. 8 shows the detail VIII according to Fig. 2, Fig. 9 shows the detail IX according to Fig. 6, Fig. 10 shows a plan view of a second embodiment of a hydraulic housing on which the invention is based,

[0033] Fig. 11 shows the partial section XI-XI according to Fig. 10 of an associated second embodiment of a hydraulic unit with the hydraulic housing according to Fig. 10,

[0034] Fig. 12 is an oblique view of a third embodiment of a hydraulic unit according to the invention without a reservoir and Fig. 13 is a comparative plan view of the reservoir side of two types of hydraulic unit, each with a type of hydraulic housing according to the first embodiment.

[0035] Fig. 1 shows a hydraulic housing 10 of a hydraulic unit 12 (Fig. 2) of a power-driven vehicle braking system (not shown in detail). The hydraulic housing 10 or casing 10 is cuboid-shaped, preferably formed from an extruded aluminum block. For this purpose, a rod-shaped extruded profile was produced in an extrusion process along an extrusion direction 14, from which a block for the housing 10 was separated, forming two opposing separating surfaces 16, 18. The two separating surfaces 16, 18 form two narrow sides of the housing 10, between which lie two further narrow sides 20, 22 and two broad sides. One broad side of this serves as the engine side 24 and the broad side opposite the engine side 24 serves as the control unit side 26. Furthermore, a separating surface 16 is a fastening side 28 or pedal side, into which a pedal (not shown) is to be inserted and to which the housing 10 is fastened to a bulkhead 30 or vehicle wall (see Fig.10 and 13) of a vehicle not shown.

[0036] The housing 10 was manufactured using a special stop concept during the extrusion process and a subsequent machining process. During the extrusion process, a first stop point 32 is provided on the narrow side 20 of the housing 10, which is adjacent to the fastening side 28 and runs along the extrusion direction 14. The first stop point 32 is arranged approximately centrally to a longitudinal extension 34 of the narrow side 20 and thus of the housing 10 as a whole, as well as close to the motor side 24. This allows the narrow side 20 to be extruded very precisely and then used in the hydraulic unit 12 as a reservoir side 36 for arranging a reservoir 38 (Fig. 2). During the machining process, the block of the housing 10 is then placed against three stop points. The first stop point 32 of the extrusion process also serves as a stop in the machining process.In addition, a second stop point 40 and a third stop point 42 are provided for machining on the parting surface 16, which are arranged in a line along a longitudinal extent 44 of the parting surface 16 and close to the control unit side 26. The second stop point 40 is arranged at a distance 46 from the narrow side 20 on the parting surface 16. The third stop point 42 is arranged only slightly spaced from the narrow side 22 opposite the reservoir side 36. With the three stop points 32, 40 and 42, the block of the housing 10 is clearly defined during machining and at the same time not over-determined. The block still has a certain freedom of movement, with which stresses are reliably avoided. This freedom of movement leads to tolerances in the direction of the narrow side 22, so that tolerances extend away from the reservoir side 36.This ensures that the reservoir side 36 is so precise that further machining, particularly milling, is unnecessary. The stop and clamping concept thus saves work steps and costs during the manufacture of the housing 10.

[0037] In a first clamping position, at least one receiving bore or channel 48 for receiving a fastening element 50 or reservoir fastening element 50 is machined on the motor side by a stepped tool. In a subsequent process, the individual channel 48 is re-machined on the motor side or from the motor side 24 using an end mill, resulting in a channel constriction 52. In a subsequent clamping position, at least one open recess 54 or pocket is machined on the reservoir side. In addition to the at least one open recess 54, at least two connection receptacles 56, 58, and 60 are machined on the reservoir side 36.

[0038] A respective connection piece 62 of the reservoir 38, shown in Fig. 3, is to be received in each of the at least two connection receptacles 56, 58 and 60. A pressure-medium-conducting contact is to be established between the respective connection receptacle 56, 58 or 60 and the reservoir 38 using the individual connection piece 62. Furthermore, the at least two connection receptacles 56, 58 and 60 are pressure-medium-conductingly connected to a pressure generator (not shown) by lines (not shown). A first connection receptacle 56 is arranged towards the fastening side 28 and is to be connected to a first chamber of the pressure generator designed as a tandem master brake cylinder. A second connection receptacle 58 is arranged facing the separating surface 18 opposite the fastening side 28 and is to be connected to a second chamber of the master brake cylinder.The master brake cylinder is to be arranged as a pressure generator parallel to the longitudinal extension 34 of the reservoir side 36 in a cylinder holder 64 open towards the fastening side 28.

[0039] Furthermore, between the first and second connection receptacles 56, 58 there is a third connection receptacle 60, which is to be connected to an external force pressure generator (not shown), such as a plunger, in a pressure-medium-conducting manner. The first and second connection receptacles 56, 58 are arranged in an imaginary line along the longitudinal extent 34. The third connection receptacle 60 is arranged between them at an offset to this imaginary line. Transverse to the connection receptacles 56, 58 and 60 and transverse to the cylinder receptacle 64, parallel to the reservoir side 36 in the housing 10, there is an external force cylinder receptacle 66. The external force pressure generator is to be accommodated therein as a cylinder-piston unit, which is to be actuated by an electric motor 68 (Fig. 2) as an external force. With the three connection receptacles 56, 58, 60, the housing 10 is intended for a one-box system. In addition, the housing 10 according to Fig. 1 forms a so-called regular hydraulic unit 12.Regular means that a mechanical actuation area, particularly determined by the master brake cylinder, is arranged between the external power cylinder receptacle 66 and the reservoir side 36.

[0040] Furthermore, the housing 10 contains additional receptacles, which are not described or named in detail and are connected to each other by means of lines. In addition to the pressure generators, other hydraulic components, such as valves, sensors, and damper chambers, are to be installed in these.

[0041] Fig. 2 shows the hydraulic unit 12 in the assembled state, looking towards the motor side 24 to which the motor 68 is attached. Opposite the control unit side 26 is an electronic control unit 70, of which only its connector housing 72 is visible. This electronic control unit 70 projects laterally beyond the control unit side 26 opposite the fastening side 28 and partially covers the separating surface 18 there. Arranged on the fastening side 28 is a mounting flange 74 with stud bolts 76 projecting perpendicular to the housing 10, with which the hydraulic unit 12 is attached to the firewall 30 of the vehicle. A projecting sleeve 78 is held on the housing 10 by the mounting flange 74, in which sleeve a piston (not shown) of the master brake cylinder is guided.

[0042] The reservoir 38 is attached to the upper narrow side 20 or reservoir side 36 adjacent to the attachment side 28, which is the upper narrow side when installed in the vehicle. The reservoir 38 is filled with brake fluid through a filler neck 80 and serves to equalize the supply of brake fluid as a pressure medium. For this purpose, at least two connection nozzles 62 are provided on a bottom side 82 of the reservoir 38 facing the housing 10 (Fig. 3). Each individual connection nozzle 62 projects into the respective associated connection receptacle 56, 58 and 60 and connects the reservoir 38 to the housing 10 and its hydraulic components. This requires sealing from the environment, for which purpose a sealing element 84 is arranged in each connection receptacle 56, 58, 60 (see also Fig. 4). Each of the sealing elements 84 is of identical design and protrudes from the reservoir side 36.For this purpose, the individual sealing element 84 is a bush-shaped sealing ring which accommodates the connection piece 62 in its interior and seals it circumferentially.

[0043] Fig. 3 shows the reservoir 38 in its unattached state with the connecting pieces 62 protruding from the bottom side 82. Furthermore, four fastening pins or eyelets 86, 88 are arranged on the bottom side 82. Two first eyelets 86, each with an associated through-opening 90, are arranged in a line along a width 92 of the reservoir 38 on a side that, in the assembled state, faces the fastening side 28. Two second eyelets 88, each with an associated through-opening 90, are arranged in a line along the width 92, which, in the assembled state, faces away from the fastening side 28. The connecting pieces 62 are located between the two second and the two first eyelets 86, 88.

[0044] Figs. 4 to 9 show a fastening of the reservoir 38 to the housing 10 by means of two fastening elements 50. For a better overview, Fig. 4 shows the hydraulic unit 12 without the reservoir 38, while the sections in Figs. 5 and 6 also show the reservoir 38. Furthermore, Figs. 7 to 9 show the individual fastening element 50 alone and in the assembled state in various detailed views.

[0045] Fig. 4 shows the sealing elements 84 arranged in the connection receptacles 56, 58 and 60 and protruding from the reservoir side 36. Furthermore, three open recesses 54 for fastening the reservoir 38 are provided on the reservoir side 36. Two of these recesses 54 are circular and are located in a line along the housing 10 with its width 94 facing the fastening side 28 and thus the mounting flange 74. In the assembled state, an eyelet 86 of the reservoir 38 is received in each of the two circular recesses 54. The third recess 54 is designed as a separate elongated hole, arranged opposite the pedal-side recesses 54 and open to the reservoir side 36 as well as open to the narrow side or separating surface 18 opposite the fastening side 28. In the assembled state, both eyelets 88 are accommodated together in the third recess 54.

[0046] In addition, there are two channels 48 in the housing 10, each of which accommodates the corresponding fastening element 50. For this purpose, the two channels 48 run perpendicularly along the width 94 of the housing 10 from the motor side 24 toward the control unit side 26. Both channels 48 end in a blind hole-like manner, or in such a way that material 96 remains on the housing 10 toward the control unit side 26. One of the two channels 48 is pierced by the two circular recesses 54 and is aligned with the through-openings 90 of the two pedal-side eyelets 86. The other channel 48 is pierced by the elongated hole-shaped recess 54 and is aligned with the through-openings 90 of the two eyelets 88 facing away from the fastening side 28.

[0047] Each channel 48 is stepped and has a channel opening 98 facing the motor side 24, adjacent to which is a channel section 100 extending from the channel opening 98 to the aforementioned channel constriction 52. The channel constriction 52 is directed radially inward as a step and has a tapered bevel 102 radially inside. The fastening element 50 rests against the channel constriction 52 with its shaft head 104, and its shaft 106 penetrates the associated channel 48 as well as the through-openings 90 of the respective eyelets 86 and 88.

[0048] In detail, the fastening element 50 is designed with a corrosion-resistant surface and has a shaft head 104 at one axial end of its shaft 106, which protrudes radially from the shaft 106. A chamfer 110 is provided at an axial end 108 opposite the shaft head 104, which tapers towards the end 108. Adjoining the chamfer 110 in the direction of the shaft head 104 is a cylindrical section 112 having a constant diameter and being designed without a thread. Adjoining the cylindrical section 112 is a conical section 114 widening towards the shaft head 106, which is followed by a threaded section 116 having a larger diameter than the cylindrical section 112. A conical stop region 118 widening towards the shaft head 104 is arranged axially between the threaded section 116 and the shaft head 104.With the stop area 118, the fastening element 50, in the assembled state, rests against the correspondingly counter-shaped chamfer 102 of the channel constriction 52, transmitting forces evenly. Forces acting on the chamfer 102 are transmitted obliquely into the housing 10 over a wide area or larger surface.

[0049] The threaded portion 116 has a self-tapping, trilobular thread 120 on its outer surface, which is designed with a standard pitch and as an M5 thread. Thus, when the fastening element 50 is screwed in, the threaded portion 116 grooves into the material 96 surrounding the channel 48. By means of a groove portion 121 of the housing 10 formed in this way, the fastening element 50 is held in the housing 10 at the threaded portion 116 in a form-fitting, stable manner and without play (Fig. 9).

[0050] At the same time, the thread 120 on the shaft 106 is only applied sequentially by means of the threaded section 116 and does not impair the cylinder section 112. Thus, the cylinder section 112 is designed to be particularly stable against transverse forces. A smaller diameter of the cylinder section 112, which is designed with a smooth outer surface, compared to the larger diameter of the threaded section 116, which is designed with the thread 120, does not have a destabilizing effect. By means of the cylinder section 112 designed in this way and the terminal chamfer 110, the fastening element 50 can be inserted easily and without tilting into the channel 48 and the through-openings 90 with clearance. In the assembled state, the reservoir 38 is retained by the cylinder section 112 on the housing 10. At the same time, the reservoir 38 is pushed away from the housing 10 by means of the then deformed and stressed sealing elements 34 by means of a prestressing force 122 against the cylinder section 112.This results in several abutments 123 on the housing 10, which act against the preload force 122 and with which the reservoir 38 is positively bonded to the housing 10. According to Fig. 5, the abutment 123 is formed in the channel 48 traversed by the slot-like recess 54 in the region of its blind-hole-like end 124, in which the axial end 108 of the fastening element 50 is trapped. In addition, the grooved section 121 serves as an abutment 123. According to Fig. 6, the abutment 123 is formed in the channel 48 traversed by two circular recesses 54 from the material 96 of the housing 10 between the two recesses 54. Here, too, the grooved section 121 serves as an additional abutment 123.

[0051] With the abutments 123, and here in particular with the grooved section 121, the fastening element 50 is so stably supported on the housing 10 that no abutment to the housing 10 is necessary directly at its axial end 108. Rather, the end 108 has a distance 125 from the material 96 of the housing 10, so that contact of the axial end 108 with the housing 10 is avoided during screwing in.

[0052] For screwing in, the fastening element 50 has a radially inner rotary drive 126 on its shaft head 104, which in this case is designed as a hexalobular socket. This eliminates the need for a working space radially outward around the shaft head 104, so that the channel section 100, with its diameter, is only slightly larger than the shaft head 104. Accordingly, more material 96 remains close to the reservoir side 36, thus stabilizing the housing 10. Furthermore, the length of the channel section 100 can be adapted to the respective housing thickness depending on the housing thickness defined by the width extension 94. A bearing section 128 facing from the channel constriction 52 into the interior of the housing 10 remains the same regardless of the housing thickness.Regardless of the housing thickness, the same fastening element 50 is always used, which can be easily rotated by means of the radially inner rotary drive 126 even in the channel section 100 with a greater length.

[0053] According to Fig. 8, in the present embodiment, the channel 48 is designed to be open at its channel section 100 toward the reservoir side 36. In an alternative not shown, the channel section 100 is designed to be axially closed. This is particularly advantageous for larger housing thicknesses.

[0054] Fig. 10 shows a housing 10 in a plan view of the reservoir side 36 and Fig. 11 shows a section of the associated hydraulic unit 12 in the assembled state. The hydraulic unit 12 shown is also a regular hydraulic unit 12 which, in contrast to the exemplary embodiment described in Figs. 1 to 9, is preferably used in a two-box system with only two connection receptacles 56 and 58. The two connection receptacles 56, 58 are arranged in an imaginary line along the longitudinal extent 34. Centrally between the two connection receptacles 56, 58 there is only a single channel 48 along the width extent 94. The channel 48 is pierced by two open recesses 54 towards the reservoir side 36, in each of which an eyelet 86 of the reservoir 38 with the through opening 90 is received. The fastening element 50 is arranged in the channel 48 and the through openings 90 as already described.This provides a uniform mounting for hydraulic units of 12 different braking systems.

[0055] The section according to Fig. 11 shows how each sealing element 84, due to its preload force 122 in the respective connection receptacle 56, 58, presses against the reservoir 38 in the assembled state. The reservoir 38 is pushed away from the housing 10, so that the eyelets 86 engage the fastening element 50 at the cylinder section 112 there. The fastening element 50 is provided with the described abutments 123 on the housing 10, with which the reservoir 38 is held to the housing 10 in a form-fitting and force-fitting manner. This holding and fastening principle applies to all exemplary embodiments.

[0056] For this purpose, each sealing element 84 is generally applied to the corresponding connecting piece 62 of the reservoir 38 for assembly of the fastening. The connecting pieces 62 thus surrounded by the sealing element 84 are inserted into the corresponding connection receptacles 56, 58, 60 of the reservoir side 36 of the housing 10. The sealing elements 84 are pressed against the housing 10 by a force introduction via rails with an assembly force on the reservoir 38 and are thus preloaded. One fastening element 50 is inserted into each of the corresponding channel 48 and the corresponding eyelets 86, 88. The fastening element 50 has play on its shaft 106. By means of the rotary drive 126 on the shaft head 104, a moment is transmitted to the fastening element 50 so that its threaded section 116 grooves into the material 96 of the housing 10.The torque is absorbed by the conical channel constriction 52, against which the fastening element 50 rests with its likewise conical stop area 118. The assembly force is then released, causing the sealing elements 84 to push the reservoir 38 away from the housing 10 due to their preload force 122.

[0057] According to Fig. 10, the recess 54 on the reservoir side 36 directed towards the motor side 24 is circular with two opposing bulges 130 extending transversely at right angles to the channel 48. Furthermore, the recess 54 directed towards the control unit side 26 is circular with two bulges 132 converging obliquely to the channel 48 and in the direction of the channel 48. Thus, a depression 134 is formed between the two bulges 132, within which the channel 48 extends in the direction of the control unit side 26. At the depression 134, the channel 48 forms an additional abutment 123 with its blind-hole-like end 124 between the two bulges 132 (as in the embodiment according to Fig. 12).

[0058] In the exemplary embodiment according to Fig. 12, in addition to the two connection receptacles 56 and 58 on the reservoir side 36, a blind receptacle 136 is arranged, with which no pressure-conducting contact can be established. Nevertheless, a sealing element 138 or blind sealing element which is identical in construction to the other sealing elements 84 and is prestressed accordingly is accommodated in the blind receptacle 136. The two connection receptacles 56 and 58 are arranged in a line along the longitudinal extent 34 of the reservoir side 36 close to the control unit side 26, while the blind receptacle 136 is offset from it and arranged close to the motor side 24 to balance the forces. Fig. 13 shows two different hydraulic units with different widths 94 and housing thicknesses. The hydraulic unit 12 is a first type of hydraulic unit 12 with the associated first type of housing 10 with a smaller housing thickness.In comparison, a second type of hydraulic unit 140 with a second type of hydraulic housing or housing 142 with a greater housing thickness is shown.

[0059] The first type of housing 10 is designed with at least one first channel 48, which has the associated first channel section 100 from the first channel opening 98 to the first channel constriction 52. The second type of housing 142 further comprises at least one second channel 144, which has an associated second channel section 146 from a second channel opening 148 to a second channel constriction 150. The two channels 48, 144 differ only in that the second channel section 146 is each axially longer than the first channel section 100. Otherwise, the channels 48, 144 are designed identically. The first fastening element 50 is accommodated in each first channel 48, and a second reservoir fastening element 152 is accommodated in each second channel 144. Both fastening elements 50, 152 are designed identically.Thanks to the internal rotary drive 126, the second fastening element 152 can be easily screwed into the axially longer second channel section 146. This allows the housings 10, 142 to be prepared with different housing thicknesses, particularly for different plunger sizes, by machining the channel sections 100, 146 to different depths. A uniform type of fastening element 50, 152 is used to attach the reservoir 38. Furthermore, in both types of hydraulic unit 12, 140, the control unit side 26 with its associated connections has a connection area 156 of the same design and thickness. In the second type of hydraulic unit 140, there is more space between the connection area 156 and the motor side 24, in particular for a larger external pressure generator and also for a larger master brake cylinder as a pressure generator.This enables the needs-based assembly of, for example, pressure generators while at the same time enabling cost-effective modular production of the two housings 10, 142.

[0060] In contrast to the first type of hydraulic unit 12, in the second type of hydraulic unit 140, the channel 144 facing away from the fastening side 28 is perforated by two second open recesses 154, instead of a single slot-shaped recess 54. The two recesses 154 are also designed as slots, each having a smaller axial extent than the slot-shaped recess 54 of the first type of hydraulic unit 12. For stabilizing purposes, a material 96 of the housing 142 surrounding the channel 144 is provided between the two recesses 54 and additionally serves as an abutment 123. Both types of hydraulic unit 12, 140 and hydraulic housing 10, 142 are of regular design and adapted for use in a one-box system.

[0061] In variants not shown, two such channels 48, 144 with channel sections 100 and 146 of different lengths are used in two types of hydraulic unit 12, 140 with the same fastening elements 50, 152, each for a two-box system, as shown in Fig. 10 and 12.

[0062] In addition, in variants (also not shown) in different types of an inverse hydraulic unit, the same fastening elements 50, 152 are always used in channels 48, 144 with channel sections 100, 146 of different lengths. Inverse means that a block underlying the housing 10 is used rotated by 180°. Thus, in the inverse hydraulic unit, in the installed position in the vehicle, a mechanical actuation area determined by the master brake cylinder is arranged on one side of the power cylinder receptacle 66, which is facing away from the reservoir side 36.

Claims

Claims 1. Reservoir fastening element (50, 152) of a hydraulic unit (12, 140) of a vehicle brake system for fastening a reservoir (38) to a hydraulic housing (10, 142), wherein the reservoir fastening element (50, 152) has a shaft (106) and a shaft head (104) at an axial end of the shaft (106), characterized in that the shaft head (104) is designed with a radially inner rotary drive (126).

2. Reservoir fastening element according to claim 1, characterized in that the rotary drive (126) is designed as a hexalobular socket.

3. Reservoir fastening element according to claim 1 or 2, characterized in that the shaft (106) has a cylindrical section (112) axially opposite the shaft head (104) and a threaded section (116) axially between the cylindrical section (112) and the shaft head (104), which is designed with a thread (120) which is in particular self-tapping.

4. Reservoir fastening element according to claim 3, characterized in that a stop region (118) is provided axially between the threaded portion (116) and the shaft head (104), which stop region is in particular conical in shape.

5. Use of at least one reservoir fastening element (50, 152) according to one of claims 1 to 4 in a hydraulic unit (12, 140) of a vehicle brake system for fastening a reservoir (38) to a hydraulic housing (10, 142), wherein the hydraulic housing (10, 142) has at least one open recess (54, 154) on its reservoir side (36) facing the reservoir (38). which is crossed by a channel (48, 144) arranged in the hydraulic housing (10, 142), and the reservoir (38) comprises at least one eyelet (86, 88) which projects from a bottom side (82) of the reservoir (38) facing the hydraulic housing (10, 142) in the direction of the hydraulic housing (10, 142) and projects into the associated open recess (54, 154) on the hydraulic housing (10, 142), and has a through-opening (90) aligned with the channel (48, 144), wherein the at least one reservoir fastening element (50, 152) is arranged with its shaft (106) penetrating the respective associated through-opening (90) in the channel (48, 144), wherein the channel (48, 144) has a Reservoir side (36) adjacent housing side (24), characterized in that a channel section (100, 146) adjoins the channel opening (98, 148) and extends from the channel opening (98, 148) to a channel constriction (52,150) and the associated reservoir fastening element (50, 152) is applied with its shaft head (104) to the channel constriction (52, 150).

6. Use according to claim 5, characterized in that the shaft head (104) is completely received in the channel section (100, 146).

7. Use according to claim 5 or 6, characterized in that the individual reservoir fastening element (50, 152) has, with its axial end (108) opposite the shaft head (104), a distance (125) from a material (96) of the hydraulic housing (10, 142) surrounding the channel (48, 144).

8. Use according to one of claims 5 to 7, characterized in that at least two connection receptacles (56, 58, 60) are arranged on the reservoir side (36), into which a respective associated connection piece (62) of the reservoir (38) is introduced for pressure-medium-conducting contact with the hydraulic housing (10, 142), and in particular a blind receptacle (136) is additionally arranged on the reservoir side (36), with which no pressure-medium-conducting contact can be established.

9. Use according to one of claims 5 to 8, characterized in that a first, second and third connection receptacle (56, 58, 60) is arranged on the reservoir side (36), into each of which an associated connection piece (62) of the reservoir (38) is introduced for pressure-medium-conducting contact with the hydraulic housing (10, 142), wherein the third connection receptacle (60) connects an external power cylinder receptacle (66) to an associated third connection piece (62) of the reservoir (38) and is arranged on the reservoir side (36) in particular between the first connection receptacle (56) and the second connection receptacle (58).

10. Use according to one of claims 5 to 9, wherein the hydraulic unit (12, 140) is a first type of hydraulic unit (12) and the hydraulic housing (10, 142) is an associated first type of hydraulic housing (10, 142) with a first channel (48) having a first channel section (100), furthermore, a second type of hydraulic unit (140) and an associated second type of hydraulic housing (142) with a second channel (144) are provided, which has a second channel section (146), and a first reservoir fastening element (50) is received in the first channel (48) and a second reservoir fastening element (152) is received in the second channel (144), characterized in that the two reservoir fastening elements (50, 152) are of the same design and the two channels (48, 144) differ in that the second channel section (146) has a greater axial length than the first channel section (100).

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