Electromechanical brake actuator, drive module for electromechanical brake actuator, and method for 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] Electromechanical brake boosters are typically used to enhance the operating force manually generated by a brake pedal, which is achieved by operating the master brake cylinder by an electric motor. In a so-called "brake-by-wire" system where a position adjustment signal is generated by operating the brake pedal or other means and an electrohydraulic actuator is operated based on the position adjustment signal to generate brake pressure, an actuator configured in a similar manner, such as an electrohydraulic 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 and converts 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, the transmission device that connects the electric motor to the 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 by 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 by the housing before the master brake cylinder is assembled.

Prior Art Documents

[0006] [Patent Document 1] German Patent No. 102013213888 Specification [Patent Document 2] German Patent Application Publication No. 102008038320 Specification [Patent Document 3] German Patent Application Publication No. 102008054852 Specification [Overview of the project]

[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 for assembling an electromechanical brake actuator having the constituent elements of claim 10 are intended.

[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 on the end face of the housing which is coaxially positioned with respect to the major axis and extends laterally with respect to the major axis; a transmission device housed in the housing having a guide portion which is slidably guided in the guide groove; at least one retaining member which is fixed in the guide groove, protruding from the end face of the housing with respect to the major axis and receding into the end face opening with respect to a radial direction which extends perpendicular to the major axis; and a return spring supported by the retaining member and the transmission device to exert an initial stress on the transmission device which 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 and a master brake cylinder having a cylinder housing with a flange having a support surface and a piston slidable within the cylinder housing, wherein the cylinder housing is 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 the respective housing notches of the flange, a return spring supported by the support surface of the flange, and the piston connected to a transmission device.

[0010] A third aspect of the present invention is intended to be a method for assembling a brake actuator according to a second aspect of the present invention. This method includes connecting the piston of a master brake cylinder to a transmission of a drive module, positioning the master brake cylinder relative to the drive module so that each retaining member is inserted into the respective housing notch of the flange, and a return spring contacts the support surface of the flange so that it disengages with respect to the long axis from the retaining member, and mounting the flange to the housing of the drive module.

[0011] The fundamental idea behind this invention is to hold the return spring of the drive module with a retaining member to prevent it from falling out during assembly. This retaining member is fixed in a guide groove provided to guide the guide portion of the transmission device, and supports only a discrete region of the circumference of the return spring. In this way, the retaining member is fixed in the pre-existing guide groove, protrudes from the guide groove beyond the end face side of the housing, and enters radially into the end face opening of the housing. Thus, the return spring also protrudes from the end face opening at one end. Therefore, for assembly, the spring can be compressed by the support surface on the flange of the master brake cylinder housing, and the retaining member fits into the respective notches on the flange or support surface.

[0012] Securing the retaining member within the pre-existing guide groove offers the advantage of improved functional integration. In particular, it enables a more compact drive module configuration for the long axis. Another advantage is that the housing does not become mechanically fragile due to the additional fixing structure for holding the retaining member.

[0013] Preferred embodiments and variations will become apparent from other dependent claims and from the description made with reference to the drawings.

[0014] In some embodiments, the housing may have a first guide groove and a second guide groove, each extending longitudinally, and a first retaining member may be fixed in the first guide groove and a second retaining member in the second guide groove, with the return spring being supported by the retaining members. In this way, the return spring is held by the retaining members at spaced intervals around its circumference. These guide grooves may be arranged in the tubular internal space of the housing, particularly facing each other, offset by, for example, 180 degrees.

[0015] The constituent elements disclosed here for one retaining member are disclosed for all retaining members if one or more retaining members are provided. In this case, it is preferable that these retaining members are identically configured.

[0016] In some embodiments, the retaining member has a base web and two side webs extending laterally to the base web and elastically deformable relative to the base web, the base web protruding radially into an end face opening, and the retaining member may be intended to elastically deform so that the side webs abut against the side walls of the guide groove. Thus the retaining member is configured substantially as a U-shaped clip, and these side webs can be bent by elastic deformation to move closer to or away from each other. In this manner, the retaining member is preferably bent inward into the guide groove and may be fixed there by, for example, a shape joint, a friction joint, or a material joint. The elastic deformability, and the fact that the side webs are subjected to initial stress by the side walls of the guide groove, result in secure and defined positioning of the retaining member, regardless of the method of fixation, thus reducing the risk of noise generation.

[0017] In some embodiments, the retaining member has leg-like webs projecting laterally from each side web, and these leg-like webs may be intended to be housed in slits formed in the housing and extending laterally to the guide grooves. These leg-like webs project away from each other or protrude from the outer surface of each side web. The slits may be located in the end regions of each guide groove, particularly facing the end face openings. The slits form pockets or notches in the opposing side walls of the guide grooves, into which the leg-like webs protrude. This enables a simple method of shape-joint fixing of the retaining member within the guide grooves.

[0018] In some embodiments, it may be intended that a slope is formed between each side web and the base web, extending radially into the end face opening, gradually increasing in the direction of the base web. This slope constitutes a kind of spacer that prevents the base web from contacting the movement area of ​​the return spring when the retaining member is displaced radially, for example, when the drive module is assembled with the master brake cylinder. This effectively prevents noise generation. In particular, this method allows the spring to be brought closer to the circumferential wall of the housing in which the guide groove is formed, thereby realizing an even more compact structure.

[0019] In some embodiments, the guide groove may be intended to communicate with an end face opening; that is, the guide groove may terminate at the end face of the housing. In this way, the retaining member can be made to protrude from the guide groove in a simple manner, and the assembly of the retaining member within 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 turn of the spiral spring contacts the retaining member. In particular, the last turn of the spiral spring may contact an inclined surface of a retaining member, which may be provided when the drive module is assembled with the master brake cylinder. Since the last turn is immobile or stationary relative to the housing, no noise is generated by the inclined surface contacting the last turn of the spiral spring during operation.

[0021] In some embodiments, the transmission device may have a threaded spindle that is non-rotatably coupled to a guide portion, and a 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 a transmission. This electric motor may be located in, mounted on, or housed within a housing.

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

Brief Description of the Drawings

[0024] [Figure 1] It is a partial view showing a brake actuator based on one embodiment of the present invention in a sectional view. [Figure 2] It is a perspective view showing a holding member of a brake actuator based on one embodiment of the present invention. [Figure 3] It is a plan view showing an end face of a housing of the brake actuator of FIG. 1. [Figure 4] It is a partial sectional view obtained when the brake actuator of FIG. 1 is cut along the long axis. [Figure 5] It is a perspective view showing a master brake cylinder of a brake actuator based on one embodiment of the present invention. [Figure 6] It is a schematic view showing the procedure of a method based on one embodiment of the present invention.

Modes for Carrying Out the Invention

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

[0026] FIG. 1 shows, as an example, a broken sectional view of an electromechanical brake actuator 300 that can be used in a vehicle's brake system, for example, as a brake booster or as a pressure generation 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 Figure 1, the drive module 100 includes a housing 1, a transmission device 2 (only partially shown in Figure 1), first and second retaining members 3A, 3B, and a return spring 4. Furthermore, an electric drive motor (not shown) may be part of the drive device 100.

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

[0029] As shown in Figures 1, 3, and 4, the housing 1 has a first guide groove 11 and a second guide groove 12 extending along or parallel to the long axis L1, preferably communicating with or ending at an end face opening 13. The guide grooves 11 and 12 are formed in particular on the circumferential wall of the housing 1, as illustrated in Figures 3 and 4. As further shown in Figure 3, it may be optionally intended that slits 14 be formed in the housing 1, particularly on the circumferential wall, extending laterally to and intersecting with the guide grooves 11 and 12, at the end regions of each guide groove 11 and 12 facing the end face opening 13.

[0030] As further shown in Figure 3, the end face 1a may optionally have an assembly hole 16, through which the master brake cylinder 200 can be attached to the housing 1, which will be explained further below.

[0031] The transmission device 2, shown only partially in Figure 1, includes a guide portion 20 and a threaded spindle 21 mounted to the guide portion 20 in a manner that prevents relative rotation. Furthermore, the transmission device 2 may have a coupling module 22 kinematically coupled to the threaded spindle 21, thereby slidable along the long axis L1. The guide portion 20 may be configured, for example, as a disc, and is guided to slide along the long axis L1 within guide grooves 11, 12. For example, the guide portion 20 may have guide projections 20A that protrude into the grooves 11, 12. The threaded spindle 21 is configured for, or coupled to, an electric drive motor (not shown), and is slidable along the long axis L1, thereby operating the master brake cylinder 200.

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

[0033] In the drive module 100 shown as an example in Figures 1, 3, and 4, first and second guide grooves 11, 12 and first and second guide members 3A, 3B are provided. In particular, one retaining member 3 may be provided for each guide groove 11, 12. However, it is also conceivable that there may be more guide grooves 11, 12 than retaining members 3. Alternatively, only one guide groove 11 and only one retaining member 3 may be provided. Therefore, the constituent requirements disclosed here for one retaining member 3 apply to all retaining members 3, and especially to the first and second retaining members 3A, 3B.

[0034] Figure 2 shows the retaining member 3 purely as an example. As shown in Figure 2, the retaining member 3 may be substantially configured as a U-shaped clip. In particular, the retaining member 3 may have one base web 30 and two side webs 31. Optionally, a leg-shaped web 32 may be provided for each side web 31.

[0035] The base web 30 is embodied as a rectangular web. The side webs 31 extend laterally from the base web 30. In particular, the side webs 31 project from the base web 30 with respect to a first direction X1 that extends perpendicularly or laterally to the base web 30. As shown in Figure 2, these side webs 31 can be folded and extended relative to each other, so that the distance d31 between them increases as the distance from the base web 30 increases. Here, the side webs 31 are sized to be elastically deformable relative to the base web 30, and in particular, to be alignable parallel to each other. The base web 30 extends in particular in planes defined by second and third directions X2 and X3 that extend perpendicularly to the first direction X1, respectively. As seen in Figure 2, the base web 30 has a width b30 that is wider with respect to the second direction X2 than the width b31 of the longitudinal web 31 in the second direction X2. As shown in Figure 2, it is optional that a slope 33 be formed between each side web 31 and the base web 30. As shown in Figure 2, the slope 33 is defined by the width b31 of the side web 31 that extends toward the base web 30 in the second direction X2.

[0036] As further illustrated in Figure 2, the optional leg-shaped webs 32 each project outward from the respective side webs 31, or in a third direction X3. In particular, the leg-shaped webs 32 may be positioned at the ends of each side web 31 opposite to the base web 30. Optionally, the leg-shaped webs 32 extend perpendicularly to the side webs 31.

[0037] The retaining member 3 may be made of a metal material in particular. For example, a semi-finished product can be milled from a thin sheet, and the base web 30, side webs 31, and optionally leg-shaped webs 32 can be manufactured by bending the milled semi-finished product.

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

[0039] In particular, as seen in Figure 4, which shows the first retaining member 3A and the first guide groove 11 purely as an example, the side webs 31 may be elastically deformed so as to extend parallel or substantially parallel to each other and be subjected to an initial stress toward the side wall 15 of the guide groove 11, thereby contacting it. An optional leg-shaped web 32 may be housed in the slit 14. The retaining member 3 is thus fixed in the guide groove 11 by a shape joint with respect to the long axis L1 and by a friction joint with respect to the radial direction R1. However, the present invention is not limited thereto, and other methods of fixing the retaining member 3 in the respective guide grooves 11, 12 are also conceivable. Furthermore, the retaining member 3 protrudes from the end face 1a of the housing 1 by the side webs 31. In particular, as seen in Figures 1 and 3, the base web 30 protrudes radially into the end face opening 13. The return spring 4 may be configured as a spiral spring and housed in the internal space 10 of the housing as shown in Figure 1. In particular, the return spring 4 may be arranged coaxially with the long axis L. As shown in Figure 1, the spring 4 is supported by the transmission device 2 at its first end, for example, by a centering sleeve 23 coupled to the connecting module 22. When the drive module 100 is in an unassembled state and not assembled with the master brake cylinder 200, the spring 4 is supported by the retaining member 3 at its second end, for example, at the last turn 40 of the spiral spring. This causes the return spring 4 to exert an initial stress on the transmission device 2, particularly the threaded spindle 21, directed away from the opening 13 along the long axis L1.

[0040] In this way, at least one retaining member 3 holds the return spring 4 so that it does not fall out of the end face opening 13 when the drive module 100 is not assembled, and holds the return spring 4 in the desired position.

[0041] The master brake cylinder 200 includes a cylinder housing 210 and a piston 220 guided axially slidably within the cylinder housing 210, as schematically and purely illustrative in Figures 1 and 5. The piston 220 serves to displace the working fluid to generate pressure increases and decreases in a wheel brake (not shown) connected to or connectable to the master brake cylinder 200.

[0042] The cylinder housing 210 has a flange 212, particularly as shown in Figure 5. The flange 212 may 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 screws (not shown). The flange 212 has an end face or support surface 212a, through which a number of accommodating notches 213 corresponding to the number of retaining members 3 of the drive module 100 are formed. The support surface 212a is preferably realized as a flat surface. As shown in Figure 5, the support surface 212a may further have an insertion opening 214 through which the piston 220 is inserted. Optionally, the flange 212 may also have a centering structure on the support surface 212a for centering the return spring 4. The centering structure may be in the form of an annular projection surrounding the insertion notch 214, protruding from the end face 212a, as shown purely as an example in Figure 5.

[0043] In Figure 1, the master brake cylinder 200 and the drive module 100 are mounted side by side by screws (not shown) that pass through mounting holes 16 and 216 in the housing 1 and cylinder housing 210, respectively. As shown in Figure 1, the support surface 212a of the flange 212 of the master brake cylinder 200 faces the end face 1a of the housing 1 of the drive module 100. Furthermore, Figure 1 shows that the respective retaining members 3A and 3B protrude into their respective housing notches 213 in the flange 212, and the return spring 4 is supported by the support surface 212a of the flange 212. That is, the retaining members 3A and 3B are load-reduced in the axial direction, or along the long axis L1. In particular, the base web 30 is no longer in contact with the spring 4. As shown in Figure 1, the inclined surface 33, which may be provided, may be in contact with the support surface 212a and remain stationary with respect to the long axis L1 even when the initial stress spring 40 is compressed or extended, and may also be in contact with the last winding 40 of the initial stress spring 4. This allows the inclined surface 33 to slide radially inward when the respective retaining members 3A and 3B are in a state where the axial load is reduced, preventing it from coming into contact with the movable winding of the spring 4, for example, by the side web 31.

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

[0045] Figure 6 schematically illustrates the procedure for method M of assembling the brake actuator 300, which will be described below, using the brake actuator described above as an example.

[0046] In step M1, the piston 220 of the master brake cylinder 200 is connected to the transmission device 2 of the drive module 100, 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, and each retaining member 3A, 3B is inserted into the respective housing notches 213 of the flange 212, and the return spring 4 contacts the support surface 212a of the flange 212, disengaging with the retaining members 3A, 3B with respect to the long axis L1. For example, the drive module 100 and the master brake cylinder 200 can be moved closer to each other along the long axis L1, thereby inserting the retaining members 3A, 3B into the housing notches 213 of the flange 212 and the return spring 4 contacts the support surface 212a of the flange 212. When a force acting along the long axis L1 is applied, the return spring 4 is compressed, thereby disengaging with the retaining members 3A, 3B with respect to the long axis L1.

[0048] In step M3, the flange 212 of the drive module 100 is finally attached to the housing 1. For example, screws (not shown) can be passed through the assembly holes 16,216 of the housing 1 and the cylinder housing 210 and secured with nuts (not shown).

[0049] Although the present invention has been described above with reference to examples, it is not limited to these and can be modified in various forms. In particular, combinations of the above examples are also possible. [Explanation of Symbols]

[0050] 1 Housing 1a End face 2. Transmission device 3A,3B Holding member 4. Return spring 11, 12 Guide grooves 13 End opening 14 slits 15 Side wall 20 Information section 21 Threaded spindle 30 Base Web 31 Sideweb 32 Leg-shaped webs 40 Wall 100 drive module 200 Master Brake Cylinder 210 Cylinder Housing 212 Flange 212a Support surface 213 Flange 220 pistons 300 Electromechanical brake actuators L1 long axis R1 Radial direction M method M1 connection M2 Positioning M3 Installation

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 the long axis (L1) and an end face opening (13) formed on the end face (1a) of the housing (1) which is positioned coaxially with respect to the long axis (L1) and extends laterally with respect to the long axis (L1), A transmission device (2) housed in the housing (1) has a guide portion (20) that is slidably guided within the guide grooves (11, 12), At least one retaining member (3) is fixed within the guide grooves (11, 12), protrudes from the end face (1a) of the housing (1) with respect to the long axis (L1), and enters the end face opening (13) with respect to the radial direction (R1) perpendicular to the long axis (L1), The retaining member (3) and the return spring (4) supported by the transmission device (2) are used to apply an initial stress to the transmission device (2) that is directed away from the opening (13) along the long axis (L1), A drive module including this.

2. The drive module (100) according to claim 1, wherein the housing (1) has a first guide groove (11) and a second guide groove (12) extending in the direction of the long axis (L1), a first retaining member (3A) is fixed in the first guide groove (11), and a second retaining member (3B) is fixed in the second guide groove (12), and the return spring (4) is supported by the retaining members (3A, 3B).

3. The drive module (100) according to claim 1 or 2, wherein the retaining 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 retaining member (3) is elastically deformed such that the side webs (31) abut against the side walls (15) of the guide grooves (11, 12).

4. The drive module (100) according to claim 3, wherein each of the retaining members (3) has a leg-shaped web (32) that protrudes laterally from each of the side webs (31), and the leg-shaped web (32) is housed in a slit (14) formed in the housing (1) and extending laterally with respect to the guide grooves (11, 12).

5. The drive module (100) according to claim 3, wherein a slope (33) is formed between each of the side webs (31) and the base web (30) and protrudes into the end face opening (13) in the radial direction (R1) such that it gradually increases in the direction of the base web (30).

6. The drive module (100) according to claim 1 or 2, wherein the guide grooves (11, 12) communicate with the end face opening (13).

7. The drive module (100) according to claim 1 or 2, wherein the return spring (4) is configured as a spiral spring, and only the last turn (40) of the spiral spring is in contact with the retaining member (3).

8. The drive module (100) according to claim 1 or 2, wherein the transmission device (2) has a threaded spindle (21) that is coupled to the guide portion (20) in a manner that prevents relative rotation, and the return spring (3) applies a return force to the threaded spindle (21).

9. An electromechanical brake actuator (300) comprising a drive module (100) according to claim 1 or 2, The system comprises a cylinder housing (210) having a flange (212) with a support surface (212a), and a master brake cylinder (200) having a piston (220) that is slidable within the cylinder housing (210), The cylinder housing (210) is attached to the housing (1) of the drive module (100) by the flange (212), and the support surface (212a) faces the end face (1a) of the housing (1). Each of the retaining members (3) protrudes into the respective housing notches (213) of the flange (212), and the return spring (4) is supported on the support surface (212a) of the flange (212). The piston (220) is an electromechanical brake actuator connected to the transmission device (2).

10. In the method (M) for assembling the brake actuator (300) according to claim 9, The piston (220) of the master brake cylinder (200) is connected (M1) to the transmission device (2) of the drive module (100), The master brake cylinder (200) is positioned (M2) relative to the drive module (100), each of the retaining members (3) is inserted into the respective housing notches (213) of the flange (212), and the return spring (4) contacts the support surface (212a) of the flange (212) so that the engagement with the retaining member (3) is disengaged with respect to the long axis (L1). A method comprising attaching (M3) the flange (212) to the housing (1) of the drive module (100).

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