CN113675993A

CN113675993A - Vehicle, electronic brake booster thereof and motor system

Info

Publication number: CN113675993A
Application number: CN202010402283.8A
Authority: CN
Inventors: 李冠奏
Original assignee: Bozewalsburg Automotive Parts Europe
Current assignee: Bozewalsburg Automotive Parts Europe; Brose Fahrzeugteile SE and Co KG
Priority date: 2020-05-13
Filing date: 2020-05-13
Publication date: 2021-11-19

Abstract

The invention relates to a vehicle, an electronic brake booster thereof and a motor system. The motor system comprises a shell, a stator, a rotor, a lead screw and a nut, wherein the stator, the rotor, the lead screw and the nut are arranged on the inner side of the shell, and the nut is meshed with the lead screw. According to the invention, the rotor is fixed with the nut on the inside. The electronic brake booster comprises the motor system. The vehicle comprises the electronic brake booster. The arrangement of the invention does not require a correspondingly large size of the housing and components therein. The motor system can thus be designed more compact and can be manufactured at lower costs.

Description

Vehicle, electronic brake booster thereof and motor system

Technical Field

The invention relates to the field of vehicles, in particular to a motor system for an electronic brake booster. The invention also relates to an electronic brake booster and a vehicle comprising the electronic brake booster.

Background

Fig. 1 and 2 show an example of a motor system for an electric brake booster of the related art, the motor system 1 including a housing 10, a stator 20, a rotor 30, a hollow shaft 40, a ball screw 50, a ball nut 60 engaged with the ball screw 50, a push rod 70, front and

rear bearings

80 and 90, and fixing means 100 and 110. The housing 10 is of cylindrical configuration and the above-mentioned components, with the exception of the housing 10, are mounted on the housing 10 or on the inside of an imaginary extension thereof, wherein the rotor 30 is fixed on the inside with the hollow shaft 40, the hollow shaft 40 is fixed on the inside with the ball screw 50, and the push rod 70 is fixed on the ball nut 60. As shown in the drawing, balls (not shown) are provided between the ball screw 50 and the ball nut 60 to form a ball screw transmission mechanism, the ball screw 50 passes through the hollow shaft 40, a rear end (right end in the drawing) thereof is fixed to the hollow shaft 40 by a fixing device 100, and the hollow shaft 40 is fitted in the housing 10 through front and rear bearings 80 so as to be rotatable with respect to the housing 10. In addition, in order to fix and protect the front bearing 80, a bearing shield 120 is provided, which is fixed inside the housing 10, and the front bearing 80 is fixed by the bearing shield 120. In order to fix and protect the rear bearing 90, a fixing device 100 fixes the inner race of the rear bearing 90 to the hollow shaft 40, and a fixing device 110 is provided which fixes the outer race of the rear bearing 90 to the housing 10. In this example of the prior art, the fixing means 100 are in the form of screws and the fixing means 110 are in the form of threaded rings which engage with complementary threads on the inner wall of the housing 10.

Fig. 1 and 2 show the motor system in a rest position in which the ball nut 60 is at its right end limit position, and in an operating position in which the ball nut 60 is moved leftward along the ball screw 50, respectively. When the motor system starts to operate, the ball screw 50 starts to rotate along with the hollow shaft 40 as the rotor 30 rotates. Furthermore, an anti-rotation device 130 is provided, which is in the form of a sleeve. With the rotation preventing means 130, the ball nut 60 can perform only a linear movement along the ball screw 50. Then, the push rod 70 is pushed forward (moved leftward in the pushing direction P' in fig. 2) to push the brake oil in the brake oil tank (not shown), thereby achieving the auxiliary braking action.

Accordingly, when the rotor 30 is rotated in the reverse direction, the ball screw 50 is linearly moved from right to left, returning the motor system from the operating position to the non-operating position.

The problems with such prior art motor systems are: the hollow shaft 40 needs to be additionally provided and many components (such as the assembly of the ball screw 50, the ball nut 60, the push rod 70 and the rotation preventing device 120) need to be fitted inside the hollow shaft 40, which means more space is required in the motor system. Moreover, there are many components (such as the housing 10, the stator 20, the rotor 30, and the bearing shield 110) that need to be designed larger than without the hollow shaft, which results in higher manufacturing costs. Further, since the ball nut 60 linearly moves along the ball screw 50, the push rod 70 fixed to the ball nut 60 needs to be provided with a through hole for the ball screw 50 to pass through, which complicates the design and also increases the manufacturing cost.

CN102483142A discloses a linear unit for applying axial force, comprising a transmission case and a motor, wherein the transmission case comprises a lead screw and a nut arranged in a transmission case housing, the motor comprises a rotor and a stator arranged in a motor housing, and the lead screw is rotatably and axially fixedly supported in the transmission case housing and connected with the rotor outside the transmission case housing.

CN105793613A discloses a linear actuator having a first and a second electric drive units, a first and a second rotary-translational drive mechanism driven by the respective electric drive units, the first and the second drive units having a first and a second drive shafts, the first drive shaft being a hollow shaft, the first and the second mechanism having a first and a second lead screw and a nut, respectively, the second drive shaft being connected with the second lead screw in a relatively non-rotatable manner through the first drive shaft.

WO2019057623a1 discloses a hollow shaft motor having a rotatably driven hollow shaft, a ball screw arranged in the hollow shaft and a ball nut which is connected to the hollow shaft in a rotationally fixed and axially movable manner.

Disclosure of Invention

The object of the present invention is to overcome the above-mentioned drawbacks of the prior art.

According to an aspect of the present invention, a motor system for an electronic brake booster is provided. The motor system comprises a shell, a stator, a rotor, a lead screw and a nut, wherein the stator, the rotor, the lead screw and the nut are arranged on the inner side of the shell, and the nut is meshed with the lead screw. According to an embodiment, the rotor is fixed with the nut on the inside, unlike the prior art arrangement (rotor fixed or connected with the screw). With this arrangement, a hollow shaft required in the prior art is no longer required, and then a large space is no longer required in the motor system, so that the motor system is more compact, and the space utilization rate is improved.

According to an embodiment, balls are provided between the screw and the nut, forming a ball screw transmission.

According to an embodiment, the motor system further comprises a push rod fixed at the front end of the lead screw.

According to an embodiment, the screw comprises a threaded section and an unthreaded section.

According to an embodiment, anti-rotation means are also provided, for example in the form of lugs projecting from the outer periphery of the non-threaded section, so that the screw can only move linearly.

According to an embodiment, the housing is of a cylindrical configuration with a closed rear end, comprising a cylindrical front section of larger diameter and a cylindrical rear section of smaller diameter, the front section and the rear section being connected by a step.

According to an embodiment, the rear section of the housing has an axially extending linear guide groove along which the anti-rotation device can be moved.

According to an embodiment, the motor system further comprises a front bearing and a rear bearing. The nut is fitted in the housing through front and rear bearings, thereby being rotatable with the rotor relative to the housing.

According to an embodiment, the step of the housing is provided with a shoulder against which the rear bearing is supported.

According to an embodiment, the electric machine system further comprises a bearing shield to protect the front bearing, which is fixed within the housing, the front bearing being fixed by the bearing shield.

According to another aspect of the present invention, there is provided an electric brake booster including the motor system described above.

According to still another aspect of the present invention, there is provided a vehicle including the electronic brake booster described above.

By replacing the linear movement of the nut in the prior art with the linear movement of the threaded spindle, the arrangement according to the invention no longer requires an additional hollow shaft and therefore no housing and components within the housing (such as stator, rotor and bearing shield) of correspondingly large dimensions. The motor system can thus be designed more compact and can be manufactured at lower costs.

Drawings

The features of the present invention and its advantages will be apparent from the following detailed description of embodiments of the invention with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. Based on the embodiments of the present invention, those skilled in the art can obtain other embodiments without creative efforts, and the embodiments are all within the protection scope of the present invention. In the drawings:

FIG. 1 is a schematic view of a prior art electric power assisted brake motor system with the motor system in an inoperative position;

FIG. 2 is a schematic illustration of the electric assist brake motor system of FIG. 1 in an operating position;

FIG. 3 is a schematic view of an electric assist brake motor system according to an embodiment of the present invention, wherein the motor system is in an inoperative position;

FIG. 4 is a schematic illustration of the electric assist brake motor system of FIG. 3 in an operating position;

FIG. 5 is a perspective view of a ball screw of the electric assist brake motor system of FIG. 3; and is

FIG. 6 is a perspective schematic view of a rear section of a housing of the electric assist brake motor system of FIG. 3.

The drawings are not necessarily to scale. Like reference symbols in the various drawings indicate like elements.

List of reference numerals

1 prior art electronic power-assisted brake motor system

10 casing

20 stator

30 rotor

40 hollow shaft

50 ball screw

60 ball nut

70 push rod

80 front bearing

90 rear bearing

100 fixing device

110 fixing device

120 bearing shield

130 anti-rotation device

P' push direction

200 electronic power-assisted brake motor system of embodiment of the invention

210 casing

211 shoulder

212 guide groove

220 stator

230 rotor

250 ball screw

251 thread segment

252 non-threaded section

253 anti-rotation device

260 ball nut

270 push rod

280 front bearing

290 rear bearing

320 bearing shield

P push direction

Detailed Description

The motor system for an electric brake booster according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. For convenience of description, directional terminology is used in the description with reference to the orientation of the figures, which may vary from actual orientation to actual orientation. For example, the left in the figure refers to the forward direction and the right refers to the backward direction.

Fig. 3 and 4 show a motor system for an electric brake booster according to an embodiment of the present invention in a non-operating position and an operating position, respectively. The motor system 200 includes a housing 210, a stator 220, a rotor 230, a ball screw 250, a ball nut 260 engaged with the ball screw 250, a push rod 270, front and

rear bearings

80 and 290, and a bearing shield 320. The housing 210 has a cylindrical configuration with a closed rear end, and includes a cylindrical front section having a large diameter and a cylindrical rear section having a small diameter, which are connected by a step, and the components except the housing 210 are mounted inside the housing 210 or an imaginary extension thereof. Balls (not shown) are disposed between the ball screw 250 and the ball nut 260 to form a ball screw transmission mechanism. Unlike the motor system 1 shown in fig. 1 and 2, in the motor system 200, the rotor 230 is fixed with the ball nut 260, and the push rod 270 is fixed to the front end (left end in the drawing) of the ball screw 250. As shown in the drawings, the ball nut 26 is fitted in the housing 210 through front and

rear bearings

280 and 290 to be rotatable with the rotor 230 relative to the housing 210. In addition, in order to fix and protect the front bearing 280, a bearing shield 320 is provided, which is fixed in the housing 210, and the front bearing 280 is fixed by the bearing shield 320. To secure and protect the rear bearing 290, the step of the housing 210 is provided with a shoulder 211 for the rear bearing 290 to rest against.

Fig. 5 shows a detail of the ball screw 250, which includes a threaded section 251 and an unthreaded section 252, the length of the unthreaded section 252 being set according to the desired travel of the push rod 270. In addition, in order for the ball screw 250 to perform only linear movement, a rotation preventing means 253 is further provided. In this example, the anti-rotation device 253 is in the form of a lug that projects from the outer periphery of the non-threaded portion 252. Fig. 6 shows a corresponding rear section of the housing 210, which has an axially extending guide groove 212, along which guide groove 212 the anti-rotation device 253 can be moved.

In the rest position shown in fig. 3, the ball screw 250 is in its right-hand end limit position, in which the anti-rotation device 253 bears against the closed rear end of the housing 210. When the motor system is operated from this rest position, the rotor 230 turns and the ball nut 260 rotates with the rotor 230, which moves the ball screw 250 to the left. The ball screw 250 can move only linearly by the rotation preventing means 253 and the guide groove 212. Then, the push rod 270 is pushed forward (moved leftward in the pushing direction P in fig. 4) to push the brake oil in the brake oil tank (not shown), thereby achieving the effect of auxiliary braking.

In the operating position shown in fig. 4, the ball screw 250 has moved into its left-hand extreme position, wherein the ball screw 250 can no longer move to the left relative to the ball nut 260 due to the unthreaded section 252.

Accordingly, when the rotor 230 is rotated in the reverse direction, the ball screw 250 is linearly moved from right to left, returning the motor system from the operating position to the non-operating position.

In some cases, features disclosed in this application may be used independently of other features. On the other hand, when necessary, the features disclosed in the present invention may be combined to provide various combinations. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles disclosed herein.

Claims

1. A motor system for an electronic brake booster, the motor system comprising a housing and, mounted inside the housing, a stator, a rotor, a screw spindle and a nut engaging with the screw spindle, characterized in that the rotor is fixed with the nut inside.

2. The motor system of claim 1, further comprising a push rod secured to a front end of the lead screw.

3. The motor system of claim 1 or 2, wherein the lead screw comprises a threaded section and an unthreaded section.

4. The electric machine system according to claim 3, wherein the non-threaded section is provided with an anti-rotation device.

5. The electric motor system set forth in claim 4, wherein the housing is of closed-rearward cylindrical configuration comprising a cylindrical forward section of greater diameter and a cylindrical rearward section of lesser diameter, the forward and rearward sections being connected by a step.

6. The electric motor system set forth in claim 5, wherein the rear section of the housing has an axially extending linear guide slot along which the anti-rotation device is movable.

7. The electric machine system according to claim 1 or 2, wherein the electric machine system further comprises a front bearing and a rear bearing, the nut being fitted in the housing through the front and rear bearings.

8. The electric machine system of claim 7, further comprising a bearing shield to protect the front bearing, the front bearing being secured within the housing by the bearing shield.

9. The electric motor system set forth in claim 6, wherein the lead screw is linearly movable relative to the nut between a first position in which the anti-rotation device abuts the rear end of the housing and a second position.

10. Electronic brake booster, characterized in that it comprises an electric machine system according to any one of claims 1 to 9.

11. Vehicle, characterized in that it comprises an electronic brake booster according to claim 10.