Drive unit for actuation device of brake system, actuation device for brake system, brake system

Abstract

The invention relates to a drive unit (13) for an actuating device (1) of a brake system (2), comprising a motor housing (14), an electric motor (15) arranged in the motor housing (14), a rotor (19) of the electric motor (15) being arranged non-rotatably in a motor shaft (20) which is rotatably mounted in the motor housing (14), and a planetary gear (23) which is rotatably mounted in the motor housing (14). The motor shaft (20) can be connected to or to an actuating element (3) of the actuating device (1) by means of a planetary gear train (23), the planetary gear train (23) having a rotatably mounted planet carrier (25), and the planet carrier (25) having an output shaft (27) and a carrier section (26) on which at least one planet gear (33) is rotatably mounted. According to the invention, the output shaft (27) and the carrier section (26) are produced independently of one another and are connected to one another in a rotationally fixed manner.

Description

Technical Field

[0001] The present invention relates to a drive unit for an operating device of a braking system, the drive unit having a motor housing and an electric motor arranged in the motor housing, wherein the rotor of the electric motor is arranged in a non-rotatable manner in a motor shaft, and the motor shaft is rotatably supported in the motor housing, the drive unit also having a planetary gear transmission mechanism, through which the motor shaft can be connected to or with an actuating element of the operating device, wherein the planetary gear transmission mechanism has a rotatably supported planetary gear carrier, and wherein the planetary gear carrier has an output shaft and a support section, and at least one planetary gear is rotatably supported on the support section.

[0002] The invention further relates to an actuating device for a brake system, which has an actuating element and a drive unit for driving the actuating element.

[0003] The invention also relates to a braking system. Background Art

[0004] Drive units of the type described at the outset are known in the prior art. With the increasing degree of electrification of motor vehicles, the operating devices of the brake systems are also becoming increasingly electrified. For this purpose, the operating device has a drive unit, which has an electric motor arranged in a motor housing. The rotor of the electric motor is arranged here in a rotationally fixed manner on a motor shaft, which is rotatably supported in the motor housing. In order to achieve high torques, a planetary gear mechanism is usually connected downstream of the motor shaft, so that the motor shaft can be connected to or with the actuating element of the operating device via the planetary gear mechanism. Usually, the planetary gear mechanism has a rotatably supported planetary gear carrier, which has an output shaft and a carrier section, on which at least one planetary gear is rotatably supported. In previously known drive units, the output shaft and the carrier section are usually constructed integrally with each other. Summary of the invention

[0005] The drive unit according to the invention having the features of claim 1 has the advantage of low manufacturing costs for the drive unit. For this purpose, it is provided according to the invention that the output shaft and the support section are manufactured independently of each other and are non-rotatably connected to each other. In general, the planetary gear carrier has a relatively complex geometry due to the support section and the output shaft, so the costs of manufacturing the planetary gear carrier in one piece are relatively high. The manufacturing costs can be reduced by independently manufacturing the output shaft and the support section. This is especially because the independent manufacturing of the support section and the output shaft allows the use of a technically simpler manufacturing process. In addition, due to the independent manufacturing, the support section and the output shaft can be easily made of different materials. Therefore, materials that are particularly suitable for the corresponding elements can be selected for the support section and the output shaft respectively. Preferably, the support section and the output shaft are made of different materials.

[0006] Preferably, the support section is made of plastic. Thus, the manufacturing costs of the support section can be further reduced. In addition, if the support section is made of plastic, its mass is small.

[0007] According to a preferred embodiment, it is provided that the output shaft is made of a metal material. As a result, the output shaft is particularly suitable for transmitting high torques. Particularly preferably, the output shaft is made of steel or aluminum.

[0008] According to a preferred embodiment, the output shaft and / or the carrier section are manufactured by extrusion. Extrusion allows the output shaft and the carrier section to be manufactured cost-effectively and in high yield. Since the output shaft and the carrier section are manufactured independently of one another, shapes that require subsequent processing of the planetary gear carrier when the planetary gear carrier is manufactured in one piece by extrusion can also be achieved in the case of independent manufacturing.

[0009] Preferably, the output shaft and the support section are connected to each other in a rotationally fixed manner by a form-fit connection. Even high torques can be reliably transmitted by the form-fit connection. In addition, the structures required for forming the form-fit connection can be realized at least substantially without additional costs, in particular when the support section and the output shaft are manufactured by extrusion. According to an alternative embodiment, the output shaft and the support section are connected to each other in a rotationally fixed manner, for example by an interference fit or by an adhesive connection.

[0010] According to a preferred embodiment, the support section has an axial recess, and the end region of the output shaft is inserted into the axial recess to form a form-fit connection. In this design of the planetary gear carrier, it is technically easy to realize the form-fit connection. For this purpose, the side wall of the support section forming the axial recess preferably has the following structure, which cooperates with a structure of the end region of the output shaft to form a form-fit connection. Preferably, the axial recess is configured as an axial penetration. This design is particularly easy to realize technically. Alternatively, the axial recess is configured, for example, as an axial recess having a bottom.

[0011] According to a preferred embodiment, the side wall of the support section forming the axial recess has an internal toothing which meshes with the external toothing of the inserted end region to form a positive connection. Such a design of a positive connection is particularly mechanically stable, which is advantageous for the transmission of high torques.

[0012] Preferably, the output shaft has a first bearing location and a second bearing location arranged at a distance from the first bearing location, wherein the first bearing location is arranged between the support section and the second bearing location. By providing two bearing locations spaced apart from each other, it is possible to achieve an accurate support of the planet carrier. Since the bearing location is formed on the output shaft, i.e. the shaft-shaped element, a relatively small diameter rotary bearing can be used to support the planet carrier. This has a favorable effect on the manufacturing costs of the drive unit. Preferably, the output shaft has an output toothing between the bearing locations.

[0013] Preferably, the diameter of the first bearing location is smaller than the diameter of the section of the output shaft arranged between the bearing locations. As mentioned above, a smaller diameter or a smaller radial extension is advantageous for the bearing location, because a small diameter rotary bearing can be used to support the bearing location. Since the output shaft and the support section are manufactured independently of each other, the rotary bearing can first be pushed onto the first bearing location when assembling the drive unit. The output shaft and the support section are then connected to each other in a non-rotatable manner. If the planetary gear carrier is of integral construction, it would be unsuitable for the diameter of the first bearing location to be smaller than the diameter of the section arranged between the bearing locations. This is because this section would hinder the pushing of the rotary bearing onto the first bearing location.

[0014] The support section is preferably designed in a plate-shaped manner. The support section thus has a high rigidity, so that even high torques can be transmitted at least substantially without deformation of the support section.

[0015] Preferably, the carrier section has at least one planetary gear shaft which is integrally formed with the carrier section. By integrally forming the planetary gear shaft and the carrier section, the number of individual parts is reduced. Furthermore, the integral formation of the planetary gear shaft and the carrier section can be achieved in a technically simple manner, in particular by extrusion.

[0016] According to a preferred embodiment, the support section is arranged in the motor housing and the output shaft protrudes from the motor housing. By arranging the support section in the motor housing, the drive unit is designed to be compact and space-saving. Since the output shaft protrudes from the motor housing, it is technically easy to achieve a transmission-technical coupling of the output shaft to a transmission element connected downstream in terms of transmission technology.

[0017] The actuating device according to the invention having the features of claim 13 is characterized in that the drive unit is designed according to the invention. This also results in the advantages already mentioned. Further preferred features and feature combinations are derived from the above description and the claims.

[0018] The brake system according to the invention having the features of claim 14 is characterized by an actuating device according to the invention. This also results in the advantages already mentioned. Further preferred features and combinations of features are derived from the above description and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be explained in more detail below with reference to the accompanying drawings. The accompanying drawings show:

[0020] Figure 1 is a cross-sectional view of an operating device for a brake system; and

[0021] Figure 2 It is the planetary gear carrier of the planetary gear transmission mechanism of the operating device. DETAILED DESCRIPTION

[0022] Figure 1 A sectional view of an actuating device 1 for a brake system 2 (not shown in detail) of a motor vehicle is shown.

[0023] The operating device 1 has a movably supported pressure element 3 or actuating element 3, which in the present case is designed as a push rod 3. The actuating element 3 can be moved in a first direction 4 and in a second direction 5 opposite to the first direction 4. The actuating element 3 is at least partially arranged in a housing 6 of the operating device 1. The master brake cylinder 7 of the operating device 1 is arranged fixedly on the housing 6 relative to the housing. A first hydraulic piston 8 and a second hydraulic piston 9 are supported in the master brake cylinder 7 movably, that is, movably in the first direction 4 and the second direction 5. The master brake cylinder 7 has a plurality of hydraulic couplings 10, 11. If the operating device 1 is installed in the brake system 2 as specified, the hydraulic couplings 10, 11 are fluidically connected to the slave cylinders of the friction brake device of the brake system 2. The friction brake device can then be actuated by moving the hydraulic pistons 8 and 9 in the first direction 4. The actuating element 3 is coupled to the hydraulic pistons 8 and 9 so that the hydraulic pistons 8, 9 can be moved in the first direction 4 by the actuating element 3. Therefore, the friction brake device can be actuated by moving the actuating element 3.

[0024] The actuating device 1 further comprises a transmission housing 12. The housing 6 and the transmission housing 12 are fixed to one another. In the present case, the transmission housing 12 is designed in the form of a hood.

[0025] The operating device 1 also has a drive unit 13. The drive unit 13 has a motor housing 14, in which an electric motor 15 is arranged. The motor housing 14 is fixed to the transmission housing 12. In the present case, the mounting surface of the motor housing flange 16 of the motor housing 14 is flatly abutted against the mounting surface of the transmission housing flange 17 of the transmission housing 12. The stator 18 of the electric motor 15 is arranged in the motor housing 14 in a manner fixed relative to the housing. The rotor 19 of the electric motor 15 is arranged on the motor shaft 20 in a rotationally fixed manner. The motor shaft 20 is supported in the motor housing 14 in a manner rotatable about the rotation axis 21.

[0026] The motor shaft 20 is coupled to the actuating element 3 via a transmission 22, so that the actuating element 3 can be moved by the motor 15. The transmission 22 has a planetary gear mechanism 23, which can be driven or rotated by the motor shaft 20. For this purpose, the sun gear 24 of the planetary gear mechanism 23 is arranged on the motor shaft 20 in a rotationally fixed manner. The planetary gear mechanism 23 has a rotatably supported planetary gear carrier 25. The rotation axis of the planetary gear carrier 25 coincides with the rotation axis 21 of the motor shaft 20. Figure 2 The design of the planetary gear carrier 25 is explained in more detail. To this end, Figure 2 A perspective view of the planet carrier 25 is shown.

[0027] The planetary gear carrier 25 has a support section 26 and an output shaft 27. The output shaft 27 and the support section 26 are manufactured independently of each other and are connected to each other in a rotationally fixed manner. That is, the planetary gear carrier 25 is constructed in multiple pieces. In the present case, the support section 26 and the output shaft 27 are respectively manufactured by stamping. The support section 26 is preferably made of plastic. The output shaft 27 is preferably made of a metal material, for example, steel or aluminum.

[0028] The output shaft 27 is an elongated or shaft-shaped component. The output shaft 27 has a first bearing location 28 and a second bearing location 29. The planet carrier 25 can be supported or supported by means of the bearing locations 28 and 29. Here, the first bearing location 28 is arranged adjacent to the carrier section 26. The second bearing location 29 is axially spaced apart from the first bearing location 28 relative to the rotation axis 21 of the motor shaft 20 or the planet carrier 25. The diameter of the bearing locations 28 and 29 is smaller than the diameter of the section 30 of the output shaft 27 located between the bearing locations 28 and 29. The section 30 located between the bearing locations 28 and 29 has an output toothing 31.

[0029] The carrier section 26 is plate-shaped. The carrier section 26 has a plurality of planetary gear shafts 32, which are integrally formed with the carrier section 26. Figure 1If the carrier section 26 is installed in the drive unit 13 or the operating device 1, a plurality of planetary gears 33 are rotatably supported on the carrier section 26 by means of planetary gear shafts 32. The carrier section 26 has a radial recess 34 between two planetary gear shafts 32 arranged successively in the circumferential direction of the carrier section 26. The radial recess 34 reduces the mass of the carrier section 26.

[0030] according to Figure 2 In the exemplary embodiment of the planetary carrier 25 shown, the output shaft 27 is connected to the carrier section 26 in a rotationally fixed manner via a positive connection 35. In the present case, the carrier section 26 has a centrally located axial penetration 36 with an internal toothing 37. An end region 38 of the output shaft 27 is inserted into the axial penetration 36. To form the positive connection 35, the end region 38 has an external toothing 39 that meshes with the internal toothing 37 of the axial penetration 36. As an alternative to the external toothing 39 and the internal toothing 37, the positive connection 35 can also be formed by providing the end region 38 and the axial penetration 36 with other cross sections than a circular shape.

[0031] from Figure 1 It can be seen that the support section 26 is arranged in the motor housing 14. The output shaft 27 protrudes axially from the motor housing 14. The planet carrier 25 is rotatably supported by bearings of the bearing points 28 and 29 of the output shaft 27. For this purpose, the drive unit 13 has a bearing cover 40 fixed relative to the housing, which supports the first bearing point 28. The bearing cover 40 has a sleeve-shaped bearing section 41, which radially surrounds the first bearing point 28. In the present case, the bearing section 41 carries a rolling element bearing 42, which acts between the bearing section 41 and the first bearing point 28. The bearing cover 40 also has a sleeve-shaped fixing section 43. The fixing section 43 rests radially against the side wall 44 of the motor housing 14 from the inside. In the present case, the bearing cover 40 is pressed into the motor housing 14. The second bearing point 29 of the output shaft 27 is rotatably supported by the gear housing 12. In the present case, the gear housing 12 has an axial penetration 45 for this purpose, through which the output shaft 27 protrudes axially. The inner side 46 of the transmission housing 12, which forms the axial penetration 45, carries a rolling element bearing 47, which acts between the transmission housing 12 and the second bearing point 29 of the output shaft 27. The gear 52 is arranged in a rotationally fixed manner between the bearing points 28 and 29 on the output shaft 27. In the present case, the gear 52 has an internal toothing (not visible in the figure) which meshes with the output toothing 31 of the section 30 of the output shaft 27 and is thus connected to the output shaft 27 in a rotationally fixed manner.

[0032] The planetary gear mechanism 23 also has a ring gear 48 fixed relative to the housing. The planetary gears 33 mesh with the sun gear 24 on the one hand and with the ring gear 48 on the other hand. The side wall outer surface 49 of the ring gear 48 is radially against the fixed section 43 of the bearing cover 40 from the inside. Therefore, the bearing cover 40 carries the ring gear 48.

[0033] In the present case, the diameter of the ring gear 48 is greater than the diameter of the electric motor 15. This allows a planetary gear mechanism 23 with a large gear ratio to be realized. The motor housing 14 is of stepped design and is thus adapted to the dimensions of the electric motor 15 and the ring gear 48. For this purpose, the motor housing 14 has a first axial section 50 assigned to the electric motor 15 and a second axial section 51 assigned to the planetary gear mechanism 23, wherein the diameter of the first axial section 50 is smaller than the diameter of the second axial section 51.

[0034] The transmission 22 further comprises a screw drive 53 with a rotatably mounted spindle nut 54. The axis of rotation 55 of the spindle nut 54 coincides with the longitudinal center axis of the actuating element 3. Furthermore, the axis of rotation 55 of the spindle nut 54 is oriented parallel to the axis of rotation 21 of the motor shaft 20. The spindle drive 53 further comprises a movable threaded spindle 56. The threaded spindle 56 can be moved by rotating the spindle nut 54, i.e., in the first direction 4 and in the second direction 5. The threaded spindle 56 is coupled to the actuating element 3 in this case, so that the actuating element 3 can be moved at least in the first direction 4 by the threaded spindle 56. The spindle drive 53 is arranged in an axial penetration 57 of the transmission housing 12.

[0035] The transmission device 22 also has another gear 58. The other gear 58 is arranged on the spindle nut 54 in a relatively rotationally fixed manner. The output tooth portion 59 of the gear 52 meshes with the drive tooth portion 60 of the other gear 58. Therefore, the other gear 58 can be rotated by the rotation of the gear 52. Therefore, the spindle transmission mechanism 53 can be driven by the motor 15, that is, it can be rotated.

[0036] On the side of the electric machine 15 facing the planetary gear 23, the motor shaft 20 is supported by a further bearing shield 61 fixed to the housing. The carrier section 26 of the planetary carrier 25 is arranged between the bearing shield 40 and the further bearing shield 61. The further bearing shield 61 has a sleeve-shaped bearing section 62 which radially surrounds the motor shaft 20 and supports the motor shaft 20. In the present case, the bearing section 62 of the further bearing shield 61 carries a rolling element bearing 63 which acts between the bearing section 62 and the motor shaft 20. In the present case, the further bearing shield 61 is pressed into the motor housing 14. The further bearing shield 61 is therefore fixed to the motor housing 14 by an interference fit acting between the further bearing shield 61 and the side wall 44 of the motor housing 14. On the side of the electric machine 15 facing away from the planetary gear 23, the motor shaft 20 is supported by a bottom 64 of the motor housing 14. For this purpose, the bottom 64 has a sleeve-shaped bearing section 65 which radially surrounds the motor shaft 20. In the present case, the bearing section 65 carries a rolling element bearing 66 which acts between the bearing section 65 and the motor shaft 20 .

[0037] The operating device 1 further comprises a control unit 67 which is designed to actuate the electric motor 15 . The control unit 67 is arranged on the housing 6 on the side of the electric motor 15 facing away from the planetary gear 23 .

[0038] The actuating device 1 further comprises an actuating element 68, which is movably supported in an axial penetration 69 of the threaded spindle 56. A first end 70 of the actuating element 68 can be coupled to or to a brake pedal of the brake system 2 via an input rod 71, so that the actuating element 68 can then be moved by actuating the brake pedal. A second end 72 of the actuating element 68 is coupled to the actuating element 3, so that the actuating element 3 can be moved by the actuating element 68. Thus, the friction brake device can also be actuated by actuating the brake pedal.

Claims

1. A drive unit for an actuating device of a brake system, the drive unit comprising a motor housing (14), an electric motor (15) arranged in the motor housing (14), wherein: The rotor (19) of the electric motor (15) is non-rotatably arranged on a motor shaft (20), which is rotatably supported in the motor housing (14), and the drive unit also has a planetary gear mechanism (23), through which the motor shaft (20) can be connected to or with an actuating element (3) of the operating device (1), wherein the planetary gear mechanism (23) has a rotatably supported planetary gear carrier (25), and wherein the planetary gear carrier (25) has an output shaft (27) and a support section (26), and at least one planetary gear (33) is rotatably supported on the support section (26), characterized in that the output shaft (27) and the support section (26) are manufactured independently of each other and are non-rotatably connected to each other.

2. The drive unit according to claim 1, characterized in that: The support section (26) is made of plastic.

3. Drive unit according to any one of the preceding claims, characterized in that The output shaft (27) is made of metal material.

4. Drive unit according to any one of the preceding claims, characterized in that The output shaft (27) and / or the support section (28) are produced by extrusion.

5. Drive unit according to any one of the preceding claims, characterized in that The output shaft (27) and the support section (26) are connected to one another in a rotationally fixed manner via a positive connection (35).

6. The drive unit according to claim 5, characterized in that: The support section (26) has an axial recess (36), and an end region (38) of the output shaft (27) is inserted into the axial recess (36) to form the form-fit connection (35).

7. The drive unit according to claim 6, characterized in that: The side wall of the support section (26) forming the axial recess (36) has an internal toothing (37) which meshes with an external toothing (39) of the inserted end region (38) to form the form-fitting connection (35).

8. Drive unit according to any one of the preceding claims, characterized in that The output shaft (27) has a first bearing point (28) and a second bearing point (29) which is arranged spaced apart from the first bearing point (28), wherein the first bearing point (28) is arranged between the support section (26) and the second bearing point (29).

9. The drive unit according to claim 8, characterized in that: The diameter of the first bearing point (28) is smaller than the diameter of a section (30) of the output shaft (27) which is arranged between the bearing points (28, 29).

10. Drive unit according to any one of the preceding claims, characterized in that The support section (26) is designed in the form of a plate.

11. Drive unit according to any one of the preceding claims, characterized in that The carrier section (26) has at least one planetary gear shaft (32) which is formed integrally with the carrier section (26).

12. Drive unit according to any one of the preceding claims, characterized in that The support section (26) is arranged in the motor housing (14), and the output shaft (27) protrudes from the motor housing (14).

13. An operating device for a brake system, comprising an actuating element (3) and a drive unit (13) for driving the actuating element (3), characterized in that: The drive unit (13) is constructed according to any of the preceding claims.

14. Braking system having an actuating device (1) according to the preceding claim.

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