A spindle drive unit for an electromechanical brake pressure generator, an electromechanical brake pressure generator

Abstract

The invention relates to a spindle drive unit (1) for an electromechanical brake pressure generator (2) in a hydraulic brake system of a vehicle, for converting the rotational movement of a drive shaft (3) of an electric motor (4) into a translational movement of a piston (5) coupled to the spindle drive unit (1). According to the invention, the spindle drive unit (1) and / or the piston (5) are at least partially surrounded by an adapter sleeve (6), which has an external thread (7) for screwing into a housing (8) of the brake pressure generator (2). The invention also relates to an electromechanical brake pressure generator (2) having such a spindle drive unit (1).

Description

Technical Field

[0001] The present invention relates to a spindle drive unit for an electromechanical brake pressure generator in a hydraulic brake system of a vehicle according to the preamble of claim 1. With the spindle drive unit according to the invention, the rotational movement of a drive shaft of an electric motor can be converted into a translational movement of a piston coupled to the spindle drive unit.

[0002] The present invention also relates to an electromechanical brake pressure generator having a spindle drive unit according to the present invention. The electromechanical brake pressure generator should be capable of providing a brake-assisting force and, in so-called "brake-by-wire" systems, also of generating only a braking force. In this embodiment, it can be used, in particular, for generating a braking force or brake pressure in autonomously driven vehicles. Background Art

[0003] The spindle drive unit for an electromechanical brake pressure generator is typically housed together with the electric motor in a common housing. The drive shaft of the electric motor can be arranged axially parallel or coaxially with the piston. In the case of an axially parallel arrangement, the axial distance between the drive shaft and the spindle drive unit is bridged by a gear transmission. In addition to a first gear or pinion coupled to the drive shaft and a second gear coupled to the spindle transmission, the gear transmission may also include an intermediate gear. The intermediate gear allows the diameters of the first and second gears to be reduced. Furthermore, the housing can accommodate the electronics, valves, and / or sensors of the electromechanical brake pressure generator.

[0004] Based on the above-mentioned prior art, the object of the present invention is to simplify the assembly of an electromechanical brake pressure generator, in particular when the drive shaft and the spindle drive are arranged axially parallel. In addition, a particularly compact structural arrangement is to be provided.

[0005] To achieve this object, a spindle drive unit is proposed having the features of claim 1 and an electromechanical brake pressure generator having the features of claim 9. Advantageous developments of the invention are disclosed in the corresponding dependent claims. Summary of the Invention

[0006] A spindle drive unit for an electromechanical brake pressure generator in a hydraulic brake system of a vehicle is proposed, with the aid of which the rotational motion of a drive shaft of an electric motor can be converted into a translational motion of a piston coupled to the spindle drive unit. According to the invention, the spindle drive unit and / or the piston are at least partially enclosed by an adapter sleeve having an external thread for screwing into a housing of the brake pressure generator.

[0007] The spindle drive unit, the piston, and the adapter sleeve can be preassembled and easily installed or screwed into the housing of the brake pressure generator as a preassembled component. As a preassembled component, the proposed spindle drive unit reduces the complexity of assembling the brake pressure generator. This is also associated with cost advantages. The threaded connection between the adapter sleeve and the housing simultaneously enables the preassembled component to be fixed in the housing, which can absorb high tensile forces. At the same time, the fixation via the threaded connection requires relatively little structural space in the radial direction, in particular compared to a clamping connection that requires a C-ring as an additional component. Therefore, in the case of an axially parallel arrangement, the axial distance between the spindle drive unit and the drive shaft of the electric motor can be reduced. This in turn allows the intermediate gear to be omitted, thereby saving an additional component.

[0008] Preferably, the spindle drive unit and the drive shaft are arranged axially parallel, since the advantages of the invention become particularly apparent here.

[0009] Furthermore, a rolling bearing or ball bearing is preferably placed, preferably press-fitted, onto the adapter sleeve. In this way, the rolling bearing or ball bearing forms another component of the preassembled assembly and can be installed into the housing together with the spindle drive unit via the adapter sleeve and fixed therein. The press-fit connection is preferably established via the inner ring of the rolling bearing or ball bearing. The press-fit of the rolling bearing or ball bearing can also transmit tensile forces acting on the piston.

[0010] Furthermore, the rolling bearing or ball bearing preferably supports the stop element of the adapter sleeve in the axial direction, i.e., in the main force direction. This axial support provides additional positional fixation in addition to the press-fit connection. To form the stop element, the adapter sleeve can, for example, have an annular collar. Alternatively, a clamping ring can be used to form the stop element.

[0011] In addition, propose that the main shaft drive unit comprises a gear for coupling with the drive shaft, preferably for directly or indirectly coupling with the pinion of the drive shaft. In this case, the gear constitutes another part of the preassembled assembly, thereby further simplifying the assembling of the brake pressure generator.

[0012] To form a torque support, it is proposed that the adapter sleeve have an inner contour with at least one groove. The principle is that a torque support is required in a spindle drive to convert the rotational motion of the drive shaft into the translational motion of the piston. For a particularly robust design of the torque support, the number of grooves can also be two, three, or four. The torque to be supported is then distributed across the plurality of grooves. Advantageously, the grooves are arranged at equal angular spacings to evenly distribute the torque to be supported.

[0013] In order to construct the torque support, it is further proposed that the spindle or the spindle nut of the spindle drive unit has an outer contour with at least one wing engaging in a groove of the adapter sleeve. The at least one wing engaging in the groove of the adapter sleeve causes a form lock in the direction of rotation between the spindle or the spindle nut and the adapter sleeve, thereby realizing torque support. When the spindle is driven, the at least one wing is constructed on the spindle nut. When the spindle nut is driven, the spindle has the at least one wing. Alternatively, it is proposed that the piston is connected to the spindle of the spindle drive unit in a rotationally fixed manner and has an outer contour with at least one wing engaging in the groove.

[0014] Preferably, the number and shape of the wings, whether constructed on the spindle, the spindle nut or the piston, correspond to the number and shape of the grooves of the adapter sleeve. Furthermore, preferably, the wings are also arranged at the same angular spacing from one another.

[0015] According to a preferred embodiment of the present invention, the adapter sleeve is made of metal, in particular steel or aluminum. Metallic materials, such as steel or aluminum, allow for the formation of precisely fitting external threads, thereby enabling the desired fixing of the adapter sleeve and the resulting preassembled assembly in the housing. This is particularly true since the housing is often also made of metallic material, in particular steel or aluminum.

[0016] In a further development of the present invention, the drive-side end of the spindle drive unit comprises a cover having at least one opening on the end for receiving an assembly tool. This cover can be used, for example, to securely hold together individual, preferably all, components of a preassembled assembly. This ensures that the assembly can be installed as a unit into the housing of the brake pressure generator. This further simplifies the assembly of the brake pressure generator. Furthermore, the cover protects the spindle drive unit from the intrusion of harmful particles. To this end, the cover preferably comprises a flange that surrounds not only the end of the spindle drive unit but also, at least partially, the adapter sleeve and / or the rolling bearing or ball bearing.

[0017] Preferably, the number and angular position of the at least one opening provided on the end face of the cover corresponds to the number and angular position of the at least one groove of the adapter sleeve. This ensures accessibility to the at least one groove of the adapter sleeve. This is because in order to screw the adapter sleeve or the preassembled component into the housing of the brake pressure generator, an assembly tool must be introduced through the at least one end face opening of the cover into the at least one groove of the adapter sleeve.

[0018] Furthermore, to achieve the aforementioned objectives, an electromechanical brake pressure generator for a hydraulic brake system of a vehicle is proposed, comprising a spindle drive unit according to the present invention. The spindle drive unit is screwed into the housing of the brake pressure generator via an adapter sleeve, which also accommodates the electric motor. The drive shafts of the spindle drive unit and the electric motor are preferably arranged axially parallel. In this arrangement, the advantages of the spindle drive unit according to the present invention are optimally utilized. In particular, a compact brake pressure generator that is easy to assemble can be provided.

[0019] Advantageously, the spindle drive unit, which is screwed into the housing via the adapter sleeve, is secured against loosening by the direction of rotation of the adapter sleeve's external thread and / or by an additional locking device, for example in the form of a coating on the external thread. In this way, the adapter sleeve, and thus the preassembled assembly, can be permanently fixed in the housing of the brake pressure generator. The additional locking device can be implemented, for example, by means of a lacquer and / or adhesive, which is preferably applied to the external thread of the adapter sleeve before the adapter sleeve is screwed into the housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Figure 1 shows a longitudinal section through an electromechanical brake pressure generator having a spindle drive unit according to the invention,

[0022] Figure 2a and Figure 2b Shown respectively Figure 1 A perspective view of the adapter sleeve of the spindle drive unit, Figure 3 Shown Figure 1 A perspective view of the spindle nut of the spindle drive unit, and

[0023] Figure 4 Shown Figure 1 A perspective view of the spindle drive unit. DETAILED DESCRIPTION

[0024] exist Figure 1 The electromechanical brake pressure generator 2 shown in FIG. 1 comprises a housing 8 in which a spindle drive unit 1 according to the invention having a piston 5 and an electric motor 4 having a drive shaft 4 are accommodated. The piston 5 and the drive shaft 3 are arranged axially parallel to each other. In other words, the longitudinal axis A1 of the piston 5 and the longitudinal axis A2 of the drive shaft 4 are oriented parallel. In this embodiment, the piston 5 is designed as a hollow cylinder that is closed at one end.

[0025] The drive shaft 4 is connected to a pinion 11, which meshes with a gear 12 of the spindle drive unit 1, thereby transmitting the rotational movement of the drive shaft 4 to the spindle drive unit 1. To convert the rotational movement of the drive shaft 4 into a translational movement of the piston 5, the spindle drive unit 1 includes a spindle 14 and a spindle nut 15, which, in the illustrated embodiment, are accommodated in the hollow cylindrical piston 5. The piston 5 is, in turn, at least partially surrounded by an adapter sleeve 6 having an external thread 7, via which the spindle drive unit 1 is screwed into the housing 8 of the brake pressure generator 2. The spindle drive unit 1 with the spindle 14 and spindle nut 15, the piston 5, and the adapter sleeve 6 form an assembly that is preassembled and installed or screwed as a unit into the housing 8 of the brake pressure generator 2. The screw connection simultaneously ensures the assembly's securement in the housing 8.

[0026] exist Figure 1 In the embodiment shown in FIG, the preassembled assembly has further components. These include the ball bearing 9 pressed onto the adapter sleeve 6 and the cover 17. The ball bearing 9 pressed onto the adapter sleeve 6 is supported in the axial direction on a stop 10, which in this case is formed by an annular collar 19 of the adapter sleeve 6 (see also FIG). Figure 2a and Figure 2b ). The cover 17 surrounds the ball bearing 9 and the end of the spindle drive unit 1 protruding from the housing 8, so that the spindle drive unit is protected by the cover 17. In addition, all parts of the preassembled assembly are held in a loss-proof manner by the cover 17, which makes it easier to install and / or screw into the housing 8. Preferably, screwing is performed with the help of an assembly tool (not shown), which engages through the opening 18 of the cover 17 in the groove 13 of the adapter sleeve 6 (see Figure 2a ) and in Figure 4 ) is shown in ).

[0027] The torque support of the spindle drive unit 1 is simultaneously achieved by the groove 13 of the adapter sleeve 6. For this purpose, the spindle nut 15 has an outer contour with wings 16 (see Figure 3 ), said wings engage in the grooves 13 of the adapter sleeve 6.

[0028] The spindle drive unit 1 according to the invention comprises all components of a preassembled assembly. Figure 4 That is to say, the spindle drive unit can further include a gear 12.

Claims

1. A spindle drive unit (1) for an electromechanical brake pressure generator (2) in a hydraulic brake system of a vehicle, the spindle drive unit being used to convert the rotational movement of a drive shaft (3) of an electric motor (4) into a translational movement of a piston (5) coupled to the spindle drive unit (1), characterized in that The spindle drive unit (1) and / or the piston (5) are at least partially surrounded by an adapter sleeve (6), which has an external thread (7) for being screwed into a housing (8) of the brake pressure generator (2). wherein the adapter sleeve (6) has an inner contour with at least one groove (13) for forming a torque support, The drive-side end of the spindle drive unit (1) has a cover (17), which has at its end at least one opening (18) for engaging an assembly tool, wherein the number and angular position of the at least one opening (18) correspond to the number and angular position of the at least one groove (13) of the adapter sleeve (6).

2. The spindle drive unit (1) according to claim 1, characterized in that A rolling bearing or ball bearing (9) is placed on the adapter sleeve (6), which is also supported on a stop (10) of the adapter sleeve (6).

3. The spindle drive unit (1) according to claim 1 or 2, characterized in that: The main shaft drive unit (1) comprises a gear (12) for coupling with the drive shaft (3).

4. The spindle drive unit (1) according to claim 1 or 2, characterized in that: The inner contour has two, three or four grooves (13) for forming a torque support.

5. The spindle drive unit (1) according to claim 4, characterized in that The spindle (14) or the spindle nut (15) of the spindle drive unit (1) has an outer contour with at least one wing (16) engaging in the groove (13).

6. The spindle drive unit (1) according to claim 4, characterized in that The piston (5) is connected to the spindle (14) of the spindle drive unit (1) in a rotationally fixed manner and has an outer contour with at least one wing (16) engaging in the groove (13).

7. The spindle drive unit (1) according to claim 1 or 2, characterized in that The adapter sleeve (6) is made of metal.

8. The spindle drive unit (1) according to claim 2, characterized in that The rolling bearing or ball bearing (9) is pressed onto the adapter sleeve (6).

9. The spindle drive unit (1) according to claim 2, characterized in that The rolling bearing or ball bearing (9) is supported in the axial direction on a stop (10) of the adapter sleeve (6).

10. The spindle drive unit (1) according to claim 3, characterized in that The gear (12) is configured to be directly or indirectly coupled to the pinion (11) of the drive shaft (3).

11. The spindle drive unit (1) according to claim 7, characterized in that The adapter sleeve (6) is made of steel or aluminum.

12. An electromechanical brake pressure generator (2) for a hydraulic brake system of a vehicle, comprising a spindle drive unit (1) according to any one of claims 1 to 11, wherein: The spindle drive unit (1) is screwed via the adapter sleeve (6) into the housing (8) of the brake pressure generator (2), in which the electric motor (4) is accommodated.

13. Electromechanical brake pressure generator (2) according to claim 12, characterized in that The spindle drive unit (1) screwed into the housing (8) via the adapter sleeve (6) is secured against loosening of the screw connection by the rotational direction of the external thread (7) of the adapter sleeve (6) and / or by an additional locking device.

14. Electromechanical brake pressure generator (2) according to claim 13, characterized in that The additional anti-loosening device is in the form of a coating of the external thread (7).

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