Operating device for a brake system

Abstract

The invention relates to an actuating device (1) for a brake system (2) comprising an electric machine (21) arranged non-rotatably on a drive shaft (23) on which a rotor (22) of the electric machine (21) is rotatably supported, a displaceably supported pressure element (3) and a transmission (26) operatively connecting the drive shaft (23) with the pressure element (3), the transmission (26) having a displaceable threaded spindle (27) and a rotation locking element (35) connected non-rotatably with the threaded spindle (27), the rotation locking element (35) cooperating with a housing (7) of the actuating device (1) and / or with an element of the actuating device (1) arranged fixedly on the housing in order to form a twist protection (44) for the threaded spindle (27). It is provided that the non-rotatable connection between the rotation locking element (35) and the threaded spindle (27) is formed by a positive connection (36).

Description

[Technical field]

[0001] The invention relates to an actuating device for a braking system comprising an electric machine, the rotor of which is arranged non-rotatably on a drive shaft, on which the rotor is rotatably supported, a displaceably supported pressure element and a transmission operatively connecting the drive shaft with the pressure element, the transmission having a displaceable threaded spindle, a rotation locking element which is connected non-rotatably with the threaded spindle, the rotation locking element cooperating with a housing of the actuating device and / or with an element of the actuating device which is arranged fixedly on the housing in order to form a twist protection for the threaded spindle.

[0002] The present invention further relates to a braking system. [Background technology]

[0003] A hydraulic brake system of a motor vehicle typically comprises a number of friction brake devices, which are operatively connected to an actuating device of the brake system in such a way that the friction brake devices can be actuated by the actuating device of the brake system. As motor vehicles become increasingly electrified, the actuating device of the brake system is also increasingly electrified. In this connection, it is known to equip an actuating device for a brake system with an electric machine, the rotor of which is arranged non-rotatably on a rotatably supported drive shaft. To enable actuation of the friction brake devices by the actuating device, the actuating device further comprises a displaceably supported pressure element. The drive shaft is operatively connected to the pressure element by a transmission, i.e. the transmission is designed to convert the rotation of the drive shaft into a translational movement of the pressure element. For this purpose, the transmission often comprises a displaceable threaded spindle. To prevent rotation of the threaded spindle during the actuation of the actuating device, a rotation locking element is usually connected non-rotatably with the threaded spindle. The rotation locking element cooperates with the housing of the actuating device and / or with an element of the actuating device which is arranged fixedly on the housing in order to form a torsion protection for the threaded spindle. In operating devices known prior to this application, the rotation locking element is typically welded to the threaded spindle, so that the non-rotatable connection between the rotation locking element and the threaded spindle is formed by a fusion connection. Summary of the Invention

[0004] The operating device according to the invention with the features of claim 1 has the advantage that the operating device can be realized in a cost-effective manner. For this purpose, it is provided for in accordance with the invention that the rotation-tight connection between the rotation locking element and the threaded spindle is formed by a form-locking connection. The form-locking connection can be produced more simply during assembly of the operating device than the above-mentioned fused connection, which results in a lower assembly cost. This allows the manufacturing costs for the operating device to be reduced. In addition, the assembly of the operating device is also facilitated by the fact that the threaded spindle and the rotation locking element do not have to be spatially accessible to the welding machine. In particular, the rotation-tight connection between the rotation locking element and the threaded spindle is produced by simply snapping the two elements together. Preferably, the rotation locking element is arranged on the threaded spindle in a rotation-tight manner. According to an advantageous embodiment, the transmission has a spindle transmission, in which case the spindle transmission has a threaded spindle. According to an alternative embodiment, the transmission preferably has a ball screw transmission, in which case the ball screw transmission has a threaded spindle. Preferably, the threaded spindle is connected with the pressure element such that the pressure element is displaceable by the threaded spindle. Alternatively, the threaded spindle preferably forms the pressure element.

[0005] According to an advantageous embodiment, it is provided that the form-locking connection is formed by at least one radially projecting interlocking element. By means of an interlocking element of this kind, a mechanically robust form-locking connection can be realized. The interlocking element then projects, for example, radially inwardly or radially outwardly. Preferably, the threaded spindle and the rotation locking element each have at least one radially projecting interlocking element, which interlocking element then cooperate to form the anti-twisting connection.

[0006] According to an advantageous embodiment, it is provided that the interlocking body toothing of the rotation locking element meshes with the interlocking body toothing of the threaded spindle to form a form-locking connection. The interlocking body toothing has a number of tooth-like interlocking body elements arranged in series in the circumferential direction. By means of the interlocking body toothing, a mechanically particularly robust form-locking connection can be realized. In particular, it is achieved that the torque transmitted from the threaded spindle to the rotation locking element during the operation of the operating device acts on the rotation locking element with a uniform distribution in the circumferential direction of the rotation locking element.

[0007] According to an advantageous embodiment, it is provided that the rotary locking element is made of plastic. By making the rotary locking element from plastic, complex geometric forms, such as for example interlocking elements or interlocking teeth, can also be produced easily. In particular, the rotary locking element is made of plastic by an injection molding process. Particularly advantageously, the rotary locking element is made of glass-fiber reinforced plastic. This material has a high strength, so that the rotary locking element can be implemented in a comparatively compact or slim manner. This saves material costs and construction space.

[0008] Preferably, the rotary locking element is made of a metallic material, which also has a high strength, so that the rotary locking element can be implemented relatively compactly, thereby saving material costs and construction space. Particularly advantageously, the rotary locking element is made of steel. Preferably, the rotary locking element is made of a metallic material by a cold forming method, for example by cold extrusion.

[0009] According to an advantageous embodiment, it is provided that the rotary locking element has a skeleton construction by means of cut-outs. In particular, if the rotary locking element is made of glass-fiber-reinforced plastic or metal material, a solid construction of the rotary locking element is not necessary for sufficient mechanical strength. The provision of cut-outs therefore allows a further reduction in material costs.

[0010] Preferably, the threaded spindle is produced by a cold forming process. By means of the cold forming process, the necessary structural elements of the threaded spindle, such as, for example, the thread of the threaded spindle or the interlocking body element or interlocking body toothing, can be produced together without a post-processing step. This makes it possible to reduce the production costs of the threaded spindle. Alternatively, the threaded spindle is produced only in part by a cold forming process. For example, a blank for the threaded spindle is first produced by a cold forming process. The thread and / or the interlocking body element or interlocking body toothing are then formed by cutting manufacturing processes, such as, for example, milling or roller burnishing.

[0011] According to an advantageous embodiment, it is provided for the rotation locking element to be axially fixedly connected to the threaded spindle with respect to the displacement axis of the threaded spindle, whereby the fixing of the rotation locking element on the threaded spindle is mechanically particularly robust and the threaded spindle together with the rotation locking element can be easily handled, for example as a preassembled assembly within the assembly of the operating device. According to an alternative embodiment, it is provided for the rotation locking element to preferably have axial play with respect to the threaded spindle.

[0012] According to an advantageous embodiment, it is provided that the threaded spindle or the rotation locking element has an undercut or undercutting into which the rotation locking element or the threaded spindle engages, thus forming an axially fixed connection between the rotation locking element and the threaded spindle. The rotation locking element or the threaded spindle engages, in particular in the radial direction, into the undercut or undercutting, resulting in a mechanically robust axially fixed connection between the rotation locking element and the threaded spindle. Preferably, the undercut or undercutting extends through the threaded spindle or the rotation locking element over the entire circumference in the circumferential direction. Such an undercut or such an undercutting can be technically easily realized.

[0013] According to an advantageous embodiment, it is provided that the rotation locking element is axially fixedly connected to the threaded spindle by caulking the rotation locking element and / or by caulking the threaded spindle. In this way, the rotation locking element and / or the threaded spindle are shaped by caulking for an axially fixed connection of the rotation locking element with the threaded spindle. This allows a mechanically particularly robust frictional and / or form-locking connection to be achieved. Preferably, the rotation locking element is shaped by caulking in such a way that it engages, in particular radially, in an undercut or undercutting of the threaded spindle. Alternatively or additionally, the threaded spindle is shaped by caulking in such a way that it engages, in particular radially, in an undercut or undercutting of the rotation locking element.

[0014] According to an advantageous embodiment, it is provided that the threaded spindle has a first end part facing the pressure element and that the rotation locking element is arranged on said first end part. The first end part is easily accessible for arranging the rotation locking element, so that an arrangement on the first end part is advantageous. In addition, arranging the rotation locking element on the first end part has the advantage that the position of the first end part in the radial direction is particularly precisely defined, which is advantageous for a reliable transmission of thrust forces from the threaded spindle to the pressure element.

[0015] According to an advantageous embodiment, it is provided that the rotation locking element has a ring-shaped part and that the threaded spindle is inserted into a through-hole of the ring-shaped part. This advantageously allows a form-locking connection between the rotation locking element and the threaded spindle. For this purpose, preferably, the lateral inner surface of the rotation locking element, which forms the through-hole, has the interlocking body toothing of the rotation locking element. Preferably, the lateral outer surface of the threaded spindle, which is radially opposite to said lateral inner surface, has the interlocking body toothing of the threaded spindle. Preferably, at least one of the aforementioned cut-outs is formed in the ring-shaped part. Particularly preferably, the ring-shaped part has at least one ring-shaped cut-out and / or at least one ring-part-shaped cut-out.

[0016] Preferably, the rotation locking element has at least one radial projection, which radially engages in a radial recess of the housing of the operating device to form the twist protection. In this way, the rotation locking element cooperates with the housing of the operating device to form the twist protection. As a result, a particularly reliable twist protection is formed. Preferably, the rotation locking element has a number of radial projections, which radially engage in respective other radial recesses of the housing to form the twist protection. Particularly advantageously, the rotation locking element has two radial projections, which are arranged 180° offset in the circumferential direction of the rotation locking element. Preferably, at least one of the aforementioned cut-outs is formed in the radial projection. Particularly advantageously, the radial projection has one or more prismatic cut-outs.

[0017] Preferably, a sliding shoe is arranged on the radial projection, by means of which a frictionless guiding of the radial projection in the radial recess occurs.

[0018] Preferably, the housing is a cylindrical extrusion profile. Extrusion profiles can typically be produced cost-effectively, so that by forming the housing as an extrusion profile, the production costs for the operating device can be further reduced. The generally cylindrically formed element has a side wall that is at least substantially closed in the circumferential direction, the side wall forming or surrounding the axial penetration of the cylindrical element. Correspondingly, the cylindrical extrusion profile also has a side wall of this type and an axial penetration of this type, the axial penetration forming the housing interior of the extrusion profile. However, the expression "cylindrical" does not imply a cross section with a specific shape. Rather, the cross section of the extrusion profile may have various shapes. However, preferably, the axial penetration has an at least substantially circular cross section. Preferably, the extrusion profile is made of aluminum. In addition, forming the housing as an extrusion profile has the advantage that the above-mentioned radial recesses, into which the radial projections of the rotation locking element engage in the radial direction, can be realized without additional processing steps.

[0019] Next, the present invention will be described in more detail with reference to the drawings. [Brief description of the drawings]

[0020] [Figure 1] 1 is a longitudinal sectional view of an operating device for a brake system; [Diagram 2] FIG. 4 is another cross-sectional view of the operating device. [Diagram 3] FIG. 4 is a cross-sectional view of a transmission device of the operating device. [Figure 4] FIG. 4 is a plan view of a rotation lock element of the operating device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] 1 shows a longitudinal section through an actuating device 1 for a braking system 2 of a motor vehicle, not shown in detail. The actuating device 1 has a displaceably supported pressure element 3, which in the present embodiment is formed as a pressure bar 3. The pressure element 3 is displaceable along a displacement axis 4 in a first direction 5 and in a second direction 6 opposite to the first direction 5. The displacement axis 4 corresponds to a longitudinal central axis of the pressure element 3.

[0022] The pressure element 3 is arranged at least partially in a housing 7 of the operating device 1. In this embodiment, the housing 7 is a cylindrical extrusion profile 7. In this respect, the housing 7 has a circumferentially closed side wall 8. The side wall 8 forms or surrounds an axial through-hole 9 of the housing 7, the axial through-hole 9 forming a housing interior 10 of the housing 7. In this embodiment, the axial through-hole 9 has a circular cross-section. The pressure element 3 is arranged in the housing 7 or in the housing interior 10 such that the displacement axis 4 is oriented perpendicular to the cross-section of the housing 7.

[0023] A brake master cylinder 11 of the actuating device 1 is fixedly arranged in the housing 7. In the present embodiment, the brake master cylinder 11 is arranged on a first end face 12 of the side wall 8. A first hydraulic piston 13 and a second hydraulic piston 14 are supported in the brake master cylinder 11 so as to be displaceable, i.e. in a first direction 5 and in a second direction 6. The brake master cylinder 11 has a number of hydraulic connections 15, 16. If the actuating device 1 is installed in the brake system 2 as specified, the hydraulic connections 15, 16 are fluidically connected with slave cylinders of a friction brake device of the brake system 2. The friction brake device can then be actuated in the first direction 5 by the displacement of the hydraulic pistons 13, 14. The pressure element 3 is connected to the hydraulic pistons 13 and 14 in such a way that the hydraulic pistons 13 and 14 can be displaced in the first direction 5 by the pressure element 3. In this way, the friction brake device can be actuated by displacing the pressure element 3.

[0024] A housing plate 17 is further arranged on the housing 7 and fixed thereto. In the present embodiment, the housing plate 17 is arranged on a second end face 18 of the side wall 8, facing away from the first end face 12. The housing plate 17 at least partially closes the axial through-hole 9.

[0025] The operating device 1 further comprises a drive unit 19. An embodiment of the drive unit 19 is explained in detail below with reference to FIG. 2, which shows a cross section of the operating device 1 for this purpose. The drive unit 19 comprises a motor housing 20, in which an electric machine 21 is arranged. A ring-shaped rotor 22 of the electric machine 21 is arranged non-rotatably on a drive shaft 23, which is supported rotatably about a rotation axis 24. A ring-shaped stator 25 of the electric machine 21 is arranged in a housing-fixed manner in the motor housing 20 and surrounds the rotor 22 radially with respect to the rotation axis 24. The motor housing 20 is fixed to the housing 7.

[0026] The drive shaft 23 is connected to the pressure element 3 by a transmission 26 in such a way that the pressure element 3 can be displaced by the electric machine 21. FIG. 3 shows a cross-sectional view of the transmission 26. The transmission 26 has a threaded spindle 27 which is displaceable in a first direction 5 and in a second direction 6. The threaded spindle 27 is connected to the pressure element 3 in such a way that the pressure element 3 can be displaced at least in the first direction 5 by means of the threaded spindle 27. The threaded spindle 27 has a thread 28. The thread 28 forms a drive toothing of the threaded spindle 27. The threaded spindle 27 is part of a transmission 29 of the transmission 26 which is formed for converting a rotation into a translational movement of the threaded spindle 27. In the present embodiment, the transmission 29 is formed as a spindle transmission 29. In addition to the threaded spindle 27, the spindle transmission 29 has a rotatably supported spindle nut 30. The spindle nut 30 and the threaded spindle 27 are arranged coaxially with respect to one another. The driven toothing 60 of the spindle nut 30 meshes with the thread 28 of the threaded spindle 27 in such a way that the threaded spindle 28 is displaceable by rotation of the spindle nut 30. According to a further embodiment, the transmission 29 is not formed as a spindle transmission but as a ball screw transmission.

[0027] According to the embodiment shown in the figures, the transmission 26 further comprises a worm gear transmission 31 with a worm shaft 32 and a worm gear 33, the worm shaft 32 being formed by the drive shaft 23. The worm gear 33 is arranged non-rotatably on the spindle nut 30 in this embodiment. According to a further embodiment, the spindle nut 30 and the worm gear 33 are formed integrally with one another.

[0028] A rotation locking element 35 is arranged on a first end part 34 of the threaded spindle 27 facing the pressure element 3 or attached to the pressure element 3. Figure 4 shows a plan view of the rotation locking element 34, the viewing direction in this case corresponding to the second direction 6. The rotation locking element 35 is connected to the threaded spindle 27 in a non-rotatable manner. The non-rotatable connection between the rotation locking element 35 and the threaded spindle 27 is formed by a form-locking connection 36.

[0029] According to the embodiment shown in the figures, the rotation locking element 35 has a ring-shaped part 61 with a through-hole 37. The threaded spindle 27 is inserted into the through-hole 37. The inner lateral surface 38 of the rotation locking element 35, which forms the through-hole 37 or which surrounds it, has a first interlocking toothing 39 with a number of tooth-like first interlocking elements 40. The first interlocking elements 40 project radially inwards from the inner lateral surface 38. The outer lateral surface 41 of the threaded spindle 27, which faces radially opposite the inner lateral surface 38, has a second interlocking toothing 42 with a number of tooth-like second interlocking elements 43. The second interlocking elements 43 project radially outwards from the outer lateral surface 41. The first interlocking toothing 39 meshes with the second interlocking toothing 42 to form the form-locking connection 36.

[0030] The rotation locking element 35 cooperates with the housing 7 to form a twist protection 44 for the threaded spindle 27. According to another embodiment, the rotation locking element 35 does not cooperate with the housing 7, but with a housing fixing element. In this embodiment, the rotation locking element 35 has two radial projections 45 which project radially outward from the ring-shaped part 61. However, other quantities of radial projections 45 are also possible. In this embodiment, the radial projections 45 are arranged 180° offset in the circumferential direction of the rotation locking element 35. The radial projections 45 radially engage in respective other radial recesses 46 of the housing 7 to form the twist protection 44. In this embodiment, a sliding shoe 48 is arranged on each radial outer end 47 of the radial projections 45. The sliding shoes 48 ensure a friction-free guiding of the radial projections 45 into the radial recesses 46.

[0031] In this embodiment, the rotation locking element 35 is made from a glass fiber reinforced plastic, for example by injection molding. This material has such strength that a solid formation of the rotation locking element 35 is not necessary. In order to reduce material costs, the rotation locking element 35 is provided with a number of cutouts 49, so that the rotation locking element 35 is of a skeleton construction. In this embodiment, the ring-shaped part 61 has two ring-shaped cutouts 49a. The radial projections 45 each have a number of prism-shaped cutouts 49b. According to another embodiment, the rotation locking element 35 is preferably made from a metallic material, for example by cold forming. If made from a metallic material, the rotation locking element 35 also preferably has a number of cutouts 49. The threaded spindle 27, including the thread 28 and the second interlocking body toothing 42, is preferably made by cold forming.

[0032] The rotation locking element 35 is furthermore axially fixedly connected to the threaded spindle 27. For this purpose, in the present embodiment, the threaded spindle 27 has an undercut 50, which extends along the entire circumference of the threaded spindle 27. The rotation locking element 35 is formed by caulking, such that it radially engages in the undercut 50. Alternatively, the rotation locking element 35 is axially fixedly connected to the threaded spindle 27, preferably by means of a locking connection. For this purpose, for example, the rotation locking element 35 has at least one locking projection which radially engages in the undercut 50. According to another embodiment, the rotation locking element 35 has an undercut 50 and the threaded spindle 27 radially engages in the undercut 50 for an axially fixed connection of the rotation locking element 35 with the threaded spindle 27.

[0033] The actuating device 1 further comprises an actuating element 51 which is displaceably supported in an axial through-hole 52 of the threaded spindle 27. A first end 53 of the actuating element 51 can be coupled or is connected by an input rod 54 to a brake pedal of the brake system 2, so that the actuating element 51 is displaceable by actuation of the brake pedal. A second end 55 of the actuating element 51 is connected to the pressure element 3 such that the pressure element 3 is displaceable by the actuating element 51. In this way, the friction brake device can also be actuated by actuation of the brake pedal. [Explanation of symbols]

[0034] 1 Operating device 3 Pressure Elements 7 Control device housing 21 Electrical Machinery 22 Rotor 23 Drive shaft 26 Transmission 27 Threaded spindle 34 First end portion of the threaded spindle 35 Rotation Locking Elements 36 Shape-restricted joints 39 First interlocking body teeth 40 First interlocking element 42 Second interlocking body teeth 43 Second interlocking element 44 Anti-twist section 45 Radial protrusion of rotation locking element 46 Radial recess of housing 48 Slippery Shoes 49 Hollow section 50 Undercut 61 Ring-shaped part

Claims

1. An operating device for a brake system, comprising an electric machine (21), the rotor (22) of which is arranged non-rotatably on a rotatably supported drive shaft (23), a displaceably supported pressure element (3), and a transmission (26) operatively connecting the drive shaft (23) with the pressure element (3), the transmission (26) having a displaceable threaded spindle (27), a rotation locking element (35) being arranged to rotate relative to the threaded spindle (27).

1. An actuating device for a brake system, in which the rotation locking element (35) is non-rotatably connected to the threaded spindle (27) and the rotation locking element (27) cooperates with a housing (7) of the actuating device (1) and / or with an element of the actuating device (1) that is fixedly arranged on the housing to form a torsion protection (44) for the threaded spindle (27), characterized in that the non-rotatable connection between the rotation locking element (35) and the threaded spindle (27) is formed by a form-locking connection (36).

2. 2. An operating device according to claim 1, characterized in that the form-binding connection (36) is formed by at least one radially projecting interlocking element (40, 43).

3. 3. An actuating device according to claim 1 or 2, characterized in that an interlocking toothing (39) of the rotation locking element (35) meshes with an interlocking toothing (42) of the threaded spindle (27) to form the form-restrictive connection (36).

4. 4. An operating device according to claim 1, wherein the rotation locking element (35) is made of plastic, in particular of glass-fibre reinforced plastic.

5. 4. An operating device according to claim 1, wherein the rotation locking element (35) is made of metallic material, in particular by a cold forming method.

6. 6. An operating device according to claim 1, characterized in that the rotation locking element (35) is of skeleton construction with cutouts (49).

7. 7. An operating device according to claim 1, wherein the threaded spindle (27) is produced by a cold forming process.

8. 8. An operating device according to claim 1, wherein the rotation locking element (35) is axially fixedly connected to the threaded spindle (27).

9. 9. An operating device according to claim 8, characterized in that the threaded spindle (27) or the rotation locking element (35) has an undercut (50) or an undercutting portion, into which the rotation locking element (35) or the threaded spindle (27) engages to form an axially fixed connection between the rotation locking element (35) and the threaded spindle (27).

10. 10. An actuation device according to claim 8 or 9, characterized in that the rotation locking element (35) is axially fixedly connected to the threaded spindle (27) by caulking the rotation locking element (35) and / or by caulking the threaded spindle (27).

11. 11. The actuation device according to claim 1, wherein the threaded spindle (27) has a first end portion (34) on the pressure element (3) side and the rotation locking element (35) is arranged on the first end portion (34).

12. 12. An operating device according to claim 1, characterized in that the rotation locking element (35) has a ring-shaped part (61) and the threaded spindle (27) is inserted into a through-hole (37) of the ring-shaped part (61).

13. 13. The operating device according to claim 1, wherein the rotation locking element (35) has at least one radial protrusion (45), which radially engages with a radial recess (46) of the housing (7) of the operating device (1) to form the anti-twist portion (44).

14. 14. An operating device according to claim 13, characterized in that a sliding shoe (48) is arranged on the radial projection (45).

15. 15. An operating device according to any one of the preceding claims, characterized in that the housing (7) is a cylindrical extrusion profile (7).

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