Electromechanical brake actuator, drive module for an electromechanical brake actuator, and method of assembling an electromechanical brake actuator

Abstract

A drive module (100) for an electromechanical brake actuator (300) includes a housing (1) having at least one guide groove (11, 12) extending along a long axis (L1) and an end face opening (13) formed in an end face (1a) of the housing positioned coaxially with the long axis and extending laterally with respect to the long axis, a transmission (2) housed in the housing and having a guide portion (20) slidably guided in the guide groove, at least one holding member (3) fixed in the guide groove, protruding from the end face of the housing with respect to the long axis, and protruding into the end face opening with respect to a radial direction (R1) extending perpendicular to the long axis, and a return spring (4) supported by the holding member and the transmission to exert an initial stress on the transmission that is directed away from the opening along the long axis.

Description

Technical Field

[0001] The present invention relates to an electromechanical brake actuator, a drive module for an electromechanical brake actuator, and a method for assembling an electromechanical brake actuator.

Background Art

[0002] An electromechanical brake booster is typically used to enhance the operating force manually generated by a brake pedal, which is achieved by operating a master brake cylinder with an electric motor. In a so-called "brake-by-wire" system where a position adjustment signal is generated by operating the brake pedal or in other ways, and an electro-hydraulic actuator is operated based on the position adjustment signal to generate a brake pressure, an actuator configured in a similar manner, such as an electro-hydraulic brake booster, is also used.

[0003] Patent Document 1 discloses a hydraulic actuator for a brake system having a master brake cylinder, an electric motor, and a transmission device that connects the electric motor to the master brake cylinder to convert the movement of the motor into the operation of the master brake cylinder. At this time, the transmission device is housed in a housing, and the master brake cylinder is positioned at an opening of the housing.

[0004] Normally, a transmission device that connects an electric motor to a master brake cylinder is biased by a return force through a return spring, thereby supporting the movement of the transmission device to its initial position when the force generated by the electric motor is eliminated. This is described, for example, in Patent Document 2 and Patent Document 3.

[0005] The return spring is usually directly supported on a flange, and through this flange, the master brake cylinder is connected to the housing in which the transmission device is housed. Therefore, the return spring is usually held in the housing before the master brake cylinder is assembled.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0007] According to the present invention, a drive module for an electromechanical brake actuator having the constituent elements of claim 1, an electromechanical brake actuator having the constituent elements of claim 9, and a method of assembling an electromechanical brake actuator having the constituent elements of claim 10 are contemplated.

[0008] In a first aspect of the present invention, a drive module for an electromechanical brake actuator includes a housing having at least one guide groove extending along a major axis and an end face opening formed in an end face of the housing positioned coaxially with the major axis and extending laterally with respect to the major axis, a transmission accommodated in the housing having a guide portion slidably guided in the guide groove, at least one holding member fixed in the guide groove, protruding from an end face of the housing with respect to the major axis, extending perpendicularly to the major axis, and protruding into the end face opening in the radial direction, and a return spring supported by the holding member and the transmission for exerting an initial stress on the transmission that is directed away from the opening along the major axis.

[0009] In a second aspect of the present invention, an electromechanical brake actuator includes a drive module according to the first aspect of the present invention, a master brake cylinder having a cylinder housing with a flange provided with a support surface and a piston slidable within the cylinder housing, the cylinder housing being attached to the housing of the drive module by the flange, the support surface facing the end face of the housing, each retaining member protruding into a respective receiving notch of the flange, the return spring being supported on the support surface of the flange, and the piston being connected to a transmission device.

[0010] In a third aspect of the present invention, a method of assembling a brake actuator according to the second aspect of the present invention is contemplated. The method includes connecting the piston of the master brake cylinder to the transmission device of the drive module, positioning the master brake cylinder relative to the drive module such that each retaining member is inserted into a respective receiving notch of the flange, bringing the return spring into contact with the support surface of the flange such that the engagement with the retaining member is disengaged with respect to the major axis, and attaching the flange to the housing of the drive module.

[0011] The idea underlying the present invention is to hold the return spring of the drive module by a retaining member so as not to fall off during assembly, and this retaining member is fixed in a guide groove provided for guiding a guide portion of the transmission device and supports only discrete regions of the circumference of the return spring. In this way, the retaining member is fixed in the originally provided guide groove, protrudes from the guide groove beyond the end face side end of the housing, and radially protrudes into the end face opening of the housing. In this way, the return spring also protrudes from the same end face opening at one end. Therefore, for assembly, the spring can be compressed by the support surface with the flange of the housing of the master brake cylinder, while the retaining member enters into each notch in the flange or the support surface.

[0012] Fixing the holding member in the originally provided guide groove offers the advantage of improved integration of functional aspects. In particular, it is possible to realize a more compact configuration of the drive module with respect to the long axis. A further advantage is that the housing is not mechanically weakened by an additional fixing structure for holding the holding member.

[0013] Preferred embodiments and developments will become apparent from the other dependent claims, as well as from the description with reference to the figures of the drawings.

[0014] In some embodiments, the housing has a first guide groove and a second guide groove each extending in the longitudinal direction, the first holding member is fixed in the first guide groove, and the second holding member is fixed in the second guide groove, and the return spring may be intended to be supported by the holding member. In this way, the return spring is held in its circumference at spaced locations by the holding member. These guide grooves may be arranged in the tubular inner space of the housing, in particular facing each other, for example offset by 180 degrees.

[0015] The features disclosed for one holding member apply to all holding members when one or more holding members are provided. In this case, it is preferred that these holding members are identically configured.

[0016] In some embodiments, the retaining member has a base web and two side webs that extend transversely to the base web and are elastically deformable relative to the base web. The base web projects into the end face opening in the radial direction, and the retaining member may be intended to elastically deform such that the side webs abut against the side walls of the guide groove. In this way, the retaining member is configured substantially as a U-shaped clip, and these side webs can be bent so as to approach each other or move away from each other by elastic deformation. In such a manner, the retaining member is preferably bent inwardly into the guide groove and fixed there, for example, in a form-fitting, friction-fitting, or material-fitting manner. The elastic deformability and the fact that the side webs are initially stressed by the side walls of the guide groove result in a reliable and defined positioning of the retaining member regardless of the type of fixation, thereby reducing the risk of noise generation in this way.

[0017] In some embodiments, the retaining member has leg-shaped webs that project transversely from each side web, and the leg-shaped webs may be intended to be received in slits formed in the housing and extending transversely to the guide groove. These leg-shaped webs project away from each other or project from the outer surfaces of the respective side webs. The slits may be arranged, in particular, in the end region of each guide groove facing the end face opening. The slits form pockets or notches, respectively, in the opposing side walls of the guide groove, into which the leg-shaped webs project. Thereby, a form-fitting fixation of the retaining member in the guide groove is realized in a simple manner.

[0018] In some embodiments, it may be intended that a slope is formed between each side web and the base web, which slopes radially into the end face opening so as to gradually increase in the direction of the base web. This slope acts as a kind of spacer that prevents the return spring's movement area from contacting the base web when the holding member is displaced radially, for example when the drive module is assembled with the master brake cylinder. Thereby, noise generation is effectively prevented. In particular, in such a manner, the spring can be brought closer to the circumferential wall of the housing in which the guide groove is formed, thereby realizing a more compact structure.

[0019] In some embodiments, it may be intended that the guide groove communicates with the end face opening. That is, the guide groove may end at the end face of the housing. In this way, the holding member can be protruded from the guide groove in a simple manner, and the assembly of the holding member in the guide groove is further simplified.

[0020] In some embodiments, the return spring may be configured as a spiral spring, and it may be intended that only the last winding of the spiral spring contacts the holding member. In particular, the last winding of the spiral spring may contact the slope of the holding member provided optionally when the drive module is assembled with the master brake cylinder. Since the last winding is relatively stationary or fixed with respect to the housing, no noise is generated when the slope abuts against the last winding of the spiral spring during operation.

[0021] In some embodiments, the transmission device may have a threaded spindle non-rotatably coupled to the guide portion, and the return spring may be intended to apply a return force to the threaded spindle.

[0022] In some embodiments, the drive module may be intended to have an electric motor kinematically coupled to the transmission device. This electric motor may be arranged on the housing, or attached to the housing, or housed in the housing.

[0023] Next, the present invention will be described with reference to the drawings of the drawings. The drawings show the following:

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0025] In each figure, unless otherwise noted, the same reference numerals represent the same components or components with the same function.

[0026] FIG. 1 shows, by way of example, a broken sectional view of an electromechanical brake actuator 300 that can be used in a vehicle's braking system, for example, as a brake booster or as a pressure generating device independent of the brake pedal. The brake actuator 300 has a drive module 100 and a master brake cylinder 200. FIG. 3 shows a plan view of an end face of the drive module 100. FIG. 4 shows another sectional view of the drive module 100, where some components are omitted. FIG. 5 shows a perspective view of the master brake cylinder 200.

[0027] As shown in FIG. 1, the drive module 100 has a housing 1, a transmission device 2 (only partially shown in FIG. 1), first and second holding members 3A, 3B, and a return spring 4. Further, an electric drive motor (not shown) may be part of the drive device 100.

[0028] The housing 1 delimits an internal space 10. In particular, the internal space 10 may be delimited at least regionally by a cylindrical circumferential wall. Generally, the housing 1 extends along, for example, a major axis L1 that may be defined by the cylindrical axis of the internal space 10. The housing 1 has an end face opening 13 at the end face 1a that connects the end face 1a to the internal space 10. The central axis of the end face opening 13 is arranged coaxially with the major axis L1. As shown in FIG. 3, the end face opening 13 can have, for example, a circular perimeter.

[0029] As shown in FIGS. 1, 3, and 4, the housing 1 has a first guide groove 11 and a second guide groove 12 that extend along or parallel to the major axis L1, preferably communicate with the end face opening 13, or end at the end face 1a. The guide grooves 11, 12 are formed in particular in the circumferential wall of the housing 1, and the manner thereof is illustrated as an example in FIGS. 3 and 4. As further shown in FIG. 3, in the end region of each guide groove 11, 12 that faces the end face opening 13, a slit 14 that extends transversely to each guide groove 11, 12 and intersects the guide grooves 11, 12 may optionally be formed in the housing 1, in particular in the circumferential wall.

[0030] As further shown in FIG. 3, the end face 1a can optionally have a mounting hole 16 through which a master brake cylinder 200 can be mounted to the housing 1, which will be described again below.

[0031] The transmission device 2 is only partially shown in FIG. 1 and includes a guide portion 20 and a threaded spindle 21 fixedly attached to the guide portion 20 against relative rotation. Further, the transmission device 2 can have a connection module 22 kinematically connected to the threaded spindle 21 and thereby slidable along the major axis L1. The guide portion 20 may be configured, for example, as a disk and is guided to be slidable along the major axis L1 in the guide grooves 11, 12. For example, the guide portion 20 can have guide protrusions 20A that project into the grooves 11, 12. The threaded spindle 21 is configured for connection to or connected to an electric drive motor (not shown), is slidable along the major axis L1, and thereby operates the master brake cylinder 200.

[0032] As shown in FIGS. 1 and 3, the transmission device 2 is housed in the internal space 10 of the housing 1.

[0033] In the drive module 100 illustrated as an example in FIGS. 1, 3, and 4, first and second guide grooves 11, 12 and first and second guide members 3A, 3B are provided. In particular, one holding member 3 may be provided for each of the guide grooves 11, 12. However, it is also conceivable that more guide grooves 11, 12 than holding members 3 are provided. As an alternative, only one guide groove 11 and only one holding member 3 may be provided. Therefore, the components disclosed here for one holding member 3 apply to all holding members 3, particularly the first and second holding members 3A, 3B.

[0034] FIG. 2 shows the holding member 3 purely by way of example. As shown in FIG. 2, the holding member 3 may be configured as a substantially U-shaped clip. The holding member 3 can particularly have one base web 30 and two side webs 31. Optionally, leg-shaped webs 32 may be additionally provided for each of the side webs 31.

[0035] The base web 30 is embodied as a rectangular web. The side webs 31 extend transversely with respect to the base web 30 starting from the base web 30. In particular, the side webs 31 protrude from the base web 30 with respect to a first direction X1 that extends perpendicular or transversely to the base web 30. As shown in FIG. 2, these side webs 31 can be bent and extended particularly with respect to each other, whereby the distance d31 between them widens as the distance from the base web 30 increases. Here, the side webs 31 are dimensioned such that they can be elastically deformed relative to the base web 30 and, in particular, can be aligned parallel to each other. The base web 30 extends in a plane defined by second and third directions X2, X3 that extend perpendicular to the first direction X1, respectively. As can be seen in FIG. 2, the base web 30 has a width b30 that is wider than the width b31 of the longitudinal web 31 in the second direction X2 with respect to the second direction X2. As can be seen in FIG. 2, optionally, an inclined surface 33 may be formed between each side web 31 and the base web 30. As shown in FIG. 2, the inclined surface 33 is defined by the width b31 of the side web 31 that widens towards the base web 30 with respect to the second direction X2.

[0036] As further illustrated in FIG. 2 as an example, optional leg-shaped webs 32 protrude outwardly from each side web 31, or with respect to the third direction X3. In particular, the leg-shaped webs 32 may be respectively arranged at the ends of each side web 31 that are located opposite to the base web 30. Optionally, the leg-shaped webs 32 extend perpendicular to the side webs 31.

[0037] The holding member 3 may be particularly composed of a metal material. For example, a semi-finished product can be milled from a thin plate, and the base web 30, the side webs 31, and optionally the leg-shaped webs 32 can be produced by bending the milled semi-finished product.

[0038] As shown in FIGS. 1, 3, and 4, the holding members 3A, 3B may be inserted into the guide grooves 11, 12 of the housing 1 such that the holding members 3A, 3B project from the end face 1a of the housing 1 with respect to the major axis L1 and enter into the end face opening 13 with respect to the radial direction R1 extending perpendicular to the major axis L1, and may be fixed there.

[0039] In particular, as can be seen in FIG. 4 where the first holding member 3A and the first guide groove 11 are shown purely by way of example, the side webs 31 may extend parallel or substantially parallel to each other and be elastically deformed so as to apply an initial stress toward the side wall 15 of the guide groove 11 and thereby abut against it. Optional leg-shaped webs 32 may be received in the slits 14 in some cases. Thereby, the holding member 3 is fixed in the guide groove 11 in a form-fitting manner with respect to the major axis L1 and in a friction-fitting manner with respect to the radial direction R1. However, the present invention is not limited thereto, and other methods of fixing the holding member 3 in each of the guide grooves 11, 12 are also conceivable. Further, the holding member 3 projects from the end face 1a of the housing 1 with the side webs 31. In particular, as can be seen in FIGS. 1 and 3, the base web 30 projects into the end face opening 13 in the radial direction. The return spring 4 may be configured in particular as a spiral spring and is received in the internal space 10 of the housing as shown in FIG. 1. In particular, the return spring 4 may be arranged coaxially with the major axis L. As shown in FIG. 1, the spring 4 is supported by the transmission device 2 with a first end, for example, on a centering sleeve 23 coupled to the connection module 22. When the drive module 100 is in a non-assembled state where it is not assembled with the master brake cylinder 200, the spring 4 is supported by the holding member 3 with a second end, for example, with the last winding 40 of the spiral spring. Thereby, the return spring 4 exerts an initial stress on the transmission device 2, in particular on the threaded spindle 21, in a direction away from the opening 13 along the major axis L1.

[0040] In this way, at least one holding member 3 holds the return spring 4 so as not to fall off from the end face opening 13 when the drive module 100 is in an unassembled state, and holds the return spring 4 at a desired position.

[0041] As schematically and purely by way of example shown in FIGS. 1 and 5, the master brake cylinder 200 includes a cylinder housing 210 and a piston 220 slidably guided axially within the cylinder housing 210. The piston 220 serves to displace the working fluid in order to generate a pressure increase and a pressure decrease in a wheel brake (not shown) connected or connectable to the master brake cylinder 200.

[0042] The cylinder housing 210 has a flange 212, as particularly shown in FIG. 5. The flange 212 can have, for example, mounting holes 216 through which the cylinder housing 210 can be attached to the housing 1 of the drive module 100, for example by means of screws (not shown). The flange 212 has an end face or support surface 212a on which a number of receiving notches 213 corresponding to the number of holding members 3 of the drive module 100 are formed. The support surface 212a is preferably realized as a flat surface. As shown in FIG. 5, furthermore, the support surface 212a can have an insertion opening 214 through which the piston 220 is inserted. Furthermore, optionally, the flange 212 can have a centering structure on the support surface 212a for centering the return spring 4. The centering structure can be configured, purely by way of example as shown in FIG. 5, in the form of an annular projection protruding from the end face 212a and surrounding the insertion notch 214.

[0043] In FIG. 1, the master brake cylinder 200 and the drive module 100 are mounted side by side, for example, by screws (not shown) passed through the mounting holes 16, 216 of the housing 1 and the cylinder housing 210. As shown in FIG. 1, the support surface 212a of the flange 212 of the master brake cylinder 200 faces the end surface 1a of the housing 1 of the drive module 100. Further, it can be seen from FIG. 1 that each holding member 3A, 3B projects into the respective receiving notch 213 of the flange 212, and the return spring 4 is supported on the support surface 212a of the flange 212. That is, the holding members 3A, 3B are axially, or along the major axis L1, load-reduced. In particular, the base web 30 is no longer in contact with the spring 4. As can be seen in FIG. 1, the optionally provided inclined surface 33 may contact the last winding 40 of the initial stress spring 4, which abuts against the support surface 212a and is stationary with respect to the major axis L1 even when the initial stress spring 40 is compressed or extended. Thereby, the inclined surface 33 slides radially inward when the respective holding members 3A, 3B are in a state of being axially load-reduced, for example, with the side web 31, to prevent contact with the movable windings of the spring 4.

[0044] The piston 220 is connected to the transmission 2, and for example, as illustrated in FIG. 1 by way of example, the operating rod 24 of the connecting module 22 may be connected to the piston 220.

[0045] FIG. 6 schematically shows the steps of a method M for assembling a brake actuator 300, which will be described below with reference to the brake actuator described above by way of example.

[0046] In step M1, the piston 220 of the master brake cylinder 200 is connected to the transmission 2 of the drive module 100, which is effected, for example, by inserting the operating rod 24 into the corresponding interface of the piston 220 or generally by connecting it thereto.

[0047] In step M2, the master brake cylinder 200 is positioned relative to the drive module 100 such that each of the holding members 3A, 3B is inserted into a respective receiving notch 213 of the flange 212, the return spring 4 abuts against the support surface 212a of the flange 212, and the engagement with the holding members 3A, 3B is disengaged with respect to the major axis L1. For example, the drive module 100 and the master brake cylinder 200 can be moved closer to each other along the major axis L1, whereby the holding members 3A, 3B are inserted into the receiving notches 213 of the flange 212 and the return spring 4 abuts against the support surface 212a of the flange 212. By applying a force acting along the major axis L1, the return spring 4 is compressed, whereby the engagement with the holding members 3A, 3B is disengaged with respect to the major axis L1.

[0048] In step M3, finally, the flange 212 is attached to the housing 1 of the drive module 100. For example, for this purpose, a screw (not shown) can be passed through the assembly holes 16, 216 of the housing 1 and the cylinder housing 210 and fixed with a nut (not shown).

[0049] Although the present invention has been described by way of example with reference to the embodiments above, the present invention is not limited thereto and can be modified in various forms. In particular, combinations of the above embodiments are also conceivable.

Explanation of reference numerals

[0050] 1 Housing 1a End face 2 Transmission device 3A, 3B Holding members 4 Return spring 11, 12 Guide grooves 13 End face opening 14 Slit 15 Side wall 20 Guide portion 21 Threaded spindle 30 Base web 31 Side web 32 Leg-shaped web 40 Wall portion 100 Drive Module 200 Master Brake Cylinder 210 Cylinder Housing 212 Flange 212a Support Surface 213 Flange 220 Piston 300 Electro-Mechanical Brake Actuator L1 Long Axis R1 Radial Direction M Method M1 Connection M2 Positioning M3 Mounting

Claims

1. In a drive module (100) for an electromechanical brake actuator (300), a housing (1) having at least one guide groove (11, 12) extending along a long axis (L1) and an end face opening (13) formed in an end face (1a) of the housing (1) positioned coaxially with the long axis (L1) and extending laterally with respect to the long axis (L1); a transmission device (2) housed in the housing (1), having a guide portion (20) slidably guided in the guide grooves (11, 12); at least one holding member (3) fixed in the guide grooves (11, 12), protruding from the end face (1a) of the housing (1) with respect to the long axis (L1), and protruding into the end face opening (13) with respect to a radial direction (R1) extending perpendicular to the long axis (L1); a return spring (4) supported by the holding member (3) and the transmission device (2) to exert an initial stress on the transmission device (2) that is directed away from the opening (13) along the long axis (L1); A drive module comprising.

2. The housing (1) has a first guide groove (11) and a second guide groove (12) each extending in the longitudinal direction (L1), a first holding member (3A) is fixed in the first guide groove (11), and a second holding member (3B) is fixed in the second guide groove (12), and the return spring (4) is supported by the holding members (3A, 3B). The drive module (100) according to Claim 1.

3. The holding member (3) has a base web (30) and two side webs (31) extending laterally with respect to the base web (30) and elastically deformable relative to the base web (30). The base web (30) protrudes into the end face opening (13) in the radial direction (R1), and the holding member (3) elastically deforms such that the side webs (31) contact the side walls (15) of the guide grooves (11, 12). The drive module (100) according to Claim 1 or 2.

4. The holding member (3) has leg-shaped webs (32) protruding laterally from the respective side webs (31), and the leg-shaped webs (32) are housed in slits (14) formed in the housing (1) and extending laterally with respect to the guide grooves (11, 12). The drive module (100) according to claim 3.

5. Between each of the side webs (31) and the base web (30), a slope (33) that protrudes into the end face opening (13) in the radial direction (R1) so as to gradually increase in the direction of the base web (30) is formed. The drive module (100) according to claim 3 or 4.

6. The drive module (100) according to any one of claims 1 to 5, wherein the guide grooves (11, 12) communicate with the end face opening (13).

7. The return spring (4) is configured as a spiral spring, and only the last winding (40) of the spiral spring contacts the holding member (3). The drive module (100) according to any one of claims 1 to 6.

8. The transmission device (2) has a threaded spindle (21) fixedly coupled to the guide portion (20), and the return spring (3) applies a return force to the threaded spindle (21). The drive module (100) according to any one of claims 1 to 7.

9. In an electromechanical brake actuator (300), the drive module (100) according to any one of claims 1 to 8, a cylinder housing (210) having a flange (212) with a support surface (212a) and a master brake cylinder (200) having a piston (220) slidable within the cylinder housing (210), the cylinder housing (210) is attached to the housing (1) of the drive module (100) with the flange (212), and the support surface (212a) faces the end face (1a) of the housing (1), each of the holding members (3) protrudes into the respective receiving notches (213) of the flange (212), and the return spring (4) is supported by the support surface (212a) of the flange (212), The piston (220) is connected to the transmission device (2). An electromechanical brake actuator.

10. A method (M) of assembling the brake actuator (300) according to claim 9, wherein the piston (220) of the master brake cylinder (200) is connected (M1) to the transmission (2) of the drive module (100), the master brake cylinder (200) is positioned (M2) relative to the drive module (100) such that each of the holding members (3) is inserted into a respective receiving notch (213) of the flange (212), the return spring (4) abuts against the support surface (212a) of the flange (212), and engagement with the holding member (3) is disengaged with respect to the major axis (L1), and the flange (212) is attached (M3) to the housing (1) of the drive module (100).

Images