CN217575337U

CN217575337U - Electric drive

Info

Publication number: CN217575337U
Application number: CN202221677680.7U
Authority: CN
Inventors: 周日炎; 陈永辉; 唐海勇; 胡永美
Original assignee: Bosch Automotive Products Changsha Co Ltd
Current assignee: Bosch Automotive Products Changsha Co Ltd
Priority date: 2022-07-01
Filing date: 2022-07-01
Publication date: 2022-10-14
Anticipated expiration: 2032-07-01

Abstract

The present application provides an electric drive. Wherein the transmission is dynamically coupled to the armature shaft to output rotation from the output shaft upon rotation of the armature shaft. The output shaft includes an inner section and an outer section. The inner section is located in the transmission cavity. The inner section includes axially opposed first and second ends. The second end is located between the first end and the outer section, and the outer section is located outside the housing. A rolling bearing is mounted between the second end and the housing so that the resistance to rotation is less. The electric drive can fulfill the requirement of a large load at very low cost and with low operating noise.

Description

Electric drive

Technical Field

The present application relates to drive devices, and more particularly to electric drives.

Background

The electric driver of the steering column is adjusted to provide the function of electrically adjusting the position of the steering wheel of the automobile, so that comfortable experience is provided for a driver to adjust the steering wheel. The electric driver comprises an armature and a speed changer, wherein the armature generates rotation, and the rotation of the armature is reduced and increased in torque through the speed changer and then outputs rotation torque through an output shaft. According to the operation command, the electric driver repeatedly acts in two opposite directions of extension and retraction within a certain stroke. In the case of a belt-loaded steering column, the armature speed in the retraction direction will be less than the armature speed in the extension direction, sometimes too low to meet the steering column adjustment requirements. Therefore, an armature of greater nominal rotational speed is often required to power an electric drive. However, a higher speed armature will produce more noise.

SUMMERY OF THE UTILITY MODEL

The present application mainly solves at least one technical problem existing in the prior art.

To solve the above technical problem, the present application provides an electric drive including:

the transmission device comprises a shell, a transmission and a control circuit, wherein an armature cavity and a transmission cavity which are communicated with each other are arranged in the shell;

an armature comprising a stator and a rotor mounted in the armature chamber, the rotor driving an armature shaft to rotate in operation; and

a transmission mounted in the transmission cavity, the transmission being dynamically coupled between the armature shaft and an output shaft so as to output a rotation of changed rotational speed from the output shaft when the armature shaft rotates, the output shaft including an inner section and an outer section, the inner section being located in the transmission cavity, the inner section including a first end and a second end axially opposite to each other, the second end being located between the first end and the outer section, the outer section being located outside the housing, a rolling bearing being mounted between the second end and the housing.

In some embodiments, a lead screw having an external thread is provided on the outer section, a nut member having an internal thread engaged with the external thread is attached to the lead screw, and the nut member is moved in a direction away from the inner section while being held in a non-rotational manner on the lead screw when the armature is rotated in the normal direction, and moved in a direction toward the inner section while being held in a non-rotational manner on the lead screw when the armature is rotated in the reverse direction.

In some embodiments, the rolling bearing limits the output shaft from moving axially closer to the housing without limiting rotation of the output shaft, and an axial end face of the first end has a point contact with the housing, the point contact limiting axial movement of the output shaft toward the first end without limiting rotation of the output shaft.

In some embodiments, the second end is provided with a step, the rolling bearing is supported between the step and the housing, and the inner section is provided with an output worm gear located between the first end and the second end.

In some embodiments, the intermediate shaft has an intermediate worm wheel and an intermediate worm, the intermediate worm wheel is coaxially disposed with the intermediate worm, the intermediate worm is meshed with the output worm wheel, and the armature shaft has an armature worm, the armature worm is meshed with the intermediate worm wheel.

In some embodiments, the intermediate shaft is substantially perpendicular to the armature shaft, the output shaft is substantially parallel to the armature shaft, and the armature and the outer segment are located on the same side of the intermediate shaft.

In some embodiments, the rolling bearing is a flat thrust bearing, the rolling bearing includes a cage, a race, and a plurality of rollers, the rollers are cylindrical, the number of the races is one or two, the cage keeps the rollers rolling on the race at intervals, and the rotation axes of the rollers are substantially perpendicular to the output shaft.

In some embodiments, the housing is provided with a mounting portion, the mounting portion being located outside the housing, the mounting portion being for securing the electric drive to a device to which the electric drive is applied, the mounting portion being proximate the first end of the output shaft.

In some embodiments, the housing includes a transmission case and an armature case, a main body of the armature case is formed by stamping, a main body of the transmission case is formed by injection molding or casting, the armature cavity is located in the armature case, and the transmission cavity is located in the transmission case.

In some embodiments, a wedge fork is installed between the housing and the rolling bearing, a preloaded spring is installed between the wedge fork and the housing, the spring applies a force to the wedge fork towards a first direction, and the distance between the housing and the rolling bearing is increased when the wedge fork moves towards the first direction.

According to the technical scheme of the application, the rolling bearing is arranged between the second end of the inner section of the output shaft and the shell, and the inventor unexpectedly finds that under the condition of driving the steering column with a belt load, an armature with a larger nominal rotating speed is not needed, the rotating speed of the armature in the shrinking direction can keep a higher rotating speed, and the requirement for adjusting the steering column can be well met. At the same time, the noise of the armature is also kept substantially at its original level. The need for a large load is achieved at very little cost.

Drawings

Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 shows an exploded schematic view of an electric drive according to one embodiment;

FIG. 2 shows a schematic diagram of an embodiment of an electric drive;

FIG. 3 shows an enlarged partial schematic view of a bearing portion of an electric drive;

FIG. 4 shows a schematic view of rollers and a bracket of a bearing of an electric drive from the axial direction; and

fig. 5 shows a schematic view of a spacer of a bearing of an electric drive from the axial direction.

Detailed Description

Referring to fig. 1 to 3, an electric drive 100 according to some embodiments of the present application includes a housing 1, an armature 2, and a transmission 3.

The housing 1 is assembled from a plurality of parts. The housing 1 includes a transmission case 12 and an armature case 11. The body of the armature housing 11 is formed by stamping. The armature case 11 is formed by drawing processing using a steel plate, for example. An armature chamber 110 is formed in the armature housing 11. The main body of the transmission case 12 is formed by injection molding or casting. For example, the transmission cover 122 and the transmission seat 121 are formed by injection molding with plastic, and the transmission cover 122 and the transmission seat 121 are assembled to form the transmission case 12. A transmission cavity 120 is provided in the transmission housing 12. The armature chamber 110 and the transmission chamber 120 communicate with each other. The armature 2 comprises a stator and a rotor mounted in an armature chamber 110, the rotor driving the armature shaft 20 in rotation in operation.

The transmission 3 is mounted in the transmission chamber 120. The transmission 3 includes an intermediate shaft 32 and an output shaft 30. Output shaft 30 is substantially parallel to armature shaft 20, intermediate shaft 32 is substantially perpendicular to armature shaft 20, and intermediate shaft 32 is also substantially perpendicular to output shaft 30. The armature 2 is located on the same side of the intermediate shaft 32 as the outer section 306. The intermediate shaft 32 has an intermediate worm wheel 320 and an intermediate worm 322. The intermediate worm wheel 320 is disposed coaxially with the intermediate worm 322, the intermediate worm 322 meshes with the output worm wheel 308, and the armature shaft 20 has the armature worm 22. The armature worm 22 meshes with the intermediate worm wheel 320, thereby achieving dynamic coupling of the transmission 3 with the armature shaft 20. The transmission 3 performs two-stage speed reduction and conversion of the rotation of the armature shaft 20, reduces the rotation speed and increases the torque, and outputs power from the output shaft 30. That is, when the armature shaft 20 rotates, rotation with a reduced rotation speed is output from the output shaft 30.

The output shaft 30 includes an inner section 301 and an outer section 306. The inner section 301 is located within the transmission cavity 120 and the outer section 306 is located outside the housing 1. The inner section 301 includes axially opposed first and

second ends

302, 304, the second end 304 being located between the first and

outer sections

302, 306.

An axial end face of the first end 302 of the output shaft 30 has a point contact 303 with the housing 1, and the point contact 303 restricts the axial movement of the output shaft 30 toward the first end 302 without restricting the rotation of the output shaft 30. Between the second end 304 and the housing 1 is mounted a rolling bearing 4. The rolling bearing 4 restricts the movement of the output shaft 30 in the direction approaching the housing 1 without restricting the rotation of the output shaft 30. In some embodiments, the rolling bearing 4 is a flat thrust bearing 4. The rolling bearing 4 is mainly axially supported and does not provide radial support. That is, the movement of the inner section 301 of the output shaft 30 toward the opposite ends in the axial direction is restricted by the point contact 303 and the rolling bearing 4, respectively, but the resistance to the rotation of the output shaft 30 is small.

The rolling bearing 4 includes a cage 40, a race 42, and a plurality of rollers 44. The rollers 44 are cylindrical, and the cage 40 keeps the plurality of rollers 44 rolling on the race 42 in a spaced relationship with the rotational axes of the rollers 44 substantially perpendicular to the output shaft 30. The number of races 42 is one or two. In the case where the number of the raceways 42 is two, the cage 40 is installed between the two raceways 42, and the rollers 44 roll between the two raceways 42 while contacting the two raceways 42, respectively. In some embodiments, the second end 304 of the inner section 301 of the output shaft 30 is provided with a step 305. The rolling bearing 4 is mounted between the step 305 and the housing 1, and the rolling bearing 4 provides support to the step 305 and the housing 1 without restricting the axial direction of rotation. An output worm gear 308 is disposed in the inner section 301, the output worm gear 308 being located between the first end 302 and the second end 304.

A wedge fork 6 is arranged between the shell 1 and the rolling bearing 4, a preloaded spring 68 is arranged between the wedge fork 6 and the shell 1, the spring 68 applies force towards the first direction to the wedge fork 6, and the distance between the shell 1 and the rolling bearing 4 is increased when the wedge fork 6 moves towards the first direction. For example, the wedge 6 has a wedge shape with a thin front and a thick rear, and the pre-compressed spring 68 abuts on the rear end of the wedge 6, and the spring 68 applies a forward elastic force to the wedge 6. Therefore, if a gap occurs in the axial direction of the output shaft 30, the wedge fork 6 is urged by the spring 68 to advance in the radial direction of the output shaft 30. Axial play is avoided by eliminating the step 305 and the axial clearance between the rolling bearing 4 and the housing 1 by the wedge 6.

The outer section 306 is provided with a screw rod 307 with an external thread, the screw rod 307 is provided with a nut component 5, the nut component 5 is provided with an internal thread, and the internal thread is meshed with the external thread. The housing 1 is provided with a mounting portion 14, the mounting portion 14 being located outside the housing 1, the mounting portion 14 being for fixing the electric drive 100 to a device to which the electric drive 100 is applied, the mounting portion 14 being located near the first end 302 of the output shaft 30. In some embodiments, the electric drive 100 is mounted to a steering column (not shown) with bolts (not shown) through holes in the mounting portion 14. When the armature 2 rotates forward, the nut member 5 held in a non-rotating state moves on the lead screw 307 in a direction away from the inner stage 301, and the steering column is driven to extend. At this time, the housing 1 provides an axial thrust to the axial end face of the first end 302 of the output shaft 30 through the point contact 303. When the armature 2 rotates reversely, the nut member 5 held in a non-rotating state moves on the lead screw 307 in a direction to approach the inner stage 301, and the steering column is driven to shorten. At this time, the housing 1 provides axial thrust to the second end 304 of the output shaft 30 through the rolling bearing 4. The output shaft 30 is supported by sufficient thrust force with little rotational resistance regardless of the normal rotation or the reverse rotation of the armature 2. Therefore, in the case where the armature 2 outputs a small capacity, a rotation power in accordance with the demand can be output through the output shaft 30. The noise of the product armature of the electric drive 100 is kept low to achieve the need for a large load at very little cost.

Notwithstanding the above description, the scope of protection of the present application is defined by the claims.

Description of the reference numerals

Electric drive 100

Housing 1

Armature case 11

Armature chamber 110

Transmission case 12

Transmission cavity 120

Speed changing seat body 121

Speed changing cover 122

Mounting portion 14

Armature 2

Armature shaft 20

Armature worm 22

Transmission 3

Output shaft 30

Inner segment 301

First end 302

Point contact 303

Second end 304

Step 305

Outer section 306

Screw 307

Output worm gear 308

Intermediate shaft 32

Intermediate worm gear 320

Intermediate worm 322

Rolling bearing 4

Retainer 40

Seat ring 42

Roller 44

Nut member 5

Wedge fork 6

A spring 68.

Claims

1. Electric drive, characterized in that it comprises:

a housing (1) in which an armature chamber (110) and a transmission chamber (120) are provided that are in communication with each other;

an armature (2) comprising a stator and a rotor mounted in the armature chamber (110), the rotor, in operation, driving an armature shaft (20) in rotation;

a transmission (3) mounted in the transmission cavity (120), the transmission (3) being dynamically coupled between the armature shaft (20) and an output shaft (30) so as to output a rotation of changed rotation speed from the output shaft (30) when the armature shaft (20) rotates, the output shaft (30) including an inner section (301) and an outer section (306), the inner section (301) being located in the transmission cavity (120), the inner section (301) including a first end (302) and a second end (304) which are axially opposite to each other, the second end (304) being located between the first end (302) and the outer section (306), the outer section (306) being located outside the housing (1), and a rolling bearing (4) being mounted between the second end (304) and the housing (1).

2. The electric drive according to claim 1, wherein a threaded spindle (307) having an external thread is provided on the outer section (306), a nut member (5) is mounted on the threaded spindle (307), the nut member (5) having an internal thread which meshes with the external thread, the nut member (5) being held against rotation on the threaded spindle (307) to move away from the inner section (301) in the forward rotation of the armature (2), and the nut member (5) being held against rotation on the threaded spindle (307) to move closer to the inner section (301) in the reverse rotation of the armature (2).

3. Electric drive according to claim 1, wherein the rolling bearing (4) limits the movement of the output shaft (30) in the direction close to the housing (1) without limiting the rotation of the output shaft (30), and wherein an axial end face of the first end (302) has a point contact (303) with the housing (1), the point contact (303) limiting the axial movement of the output shaft (30) towards the first end (302) without limiting the rotation of the output shaft (30).

4. Electric drive according to claim 1, wherein the second end (304) is provided with a step (305), the rolling bearing (4) is supported between the step (305) and the housing (1), and an output worm gear (308) is provided at the inner section (301), the output worm gear (308) being located between the first end (302) and the second end (304).

5. Electric drive according to claim 4, comprising an intermediate shaft (32), wherein the intermediate shaft (32) has thereon an intermediate worm wheel (320) and an intermediate worm (322), the intermediate worm wheel (320) being arranged coaxially with the intermediate worm (322), the intermediate worm (322) meshing with the output worm wheel (308), the armature shaft (20) having thereon an armature worm (22), the armature worm (22) meshing with the intermediate worm wheel (320).

6. Electric drive according to claim 5, wherein the intermediate shaft (32) is substantially perpendicular to the armature shaft (20), the output shaft (30) is substantially parallel to the armature shaft (20), and the armature (2) is located on the same side of the intermediate shaft (32) as the outer section (306).

7. Electric drive according to claim 1, wherein the rolling bearing (4) is a flat thrust bearing (4), the rolling bearing (4) comprising a cage (40), a race (42) and a plurality of rollers (44), the rollers (44) being cylindrical, the number of races (42) being one or two, the cage (40) keeping the plurality of rollers (44) rolling on the race (42) at a mutual distance, the rotational axes of the rollers (44) being substantially perpendicular to the output shaft (30).

8. Electric drive according to claim 1, wherein the housing (1) is provided with a mounting portion (14), the mounting portion (14) being located outside the housing (1), the mounting portion (14) being intended for fixing the electric drive to a device to which the electric drive is applied, the mounting portion (14) being close to the first end (302) of the output shaft (30).

9. The electric drive according to claim 1, wherein the housing (1) comprises a transmission housing (12) and an armature housing (11), a body of the armature housing (11) being formed by stamping, a body of the transmission housing (12) being formed by injection molding or casting, the armature cavity (110) being located in the armature housing (11), the transmission cavity (120) being located in the transmission housing (12).

10. Electric drive according to claim 1, wherein a wedge fork (6) is mounted between the housing (1) and the rolling bearing (4), a preloaded spring (68) is mounted between the wedge fork (6) and the housing (1), the spring (68) exerting a force on the wedge fork (6) towards a first direction, the distance between the housing (1) and the rolling bearing (4) increasing in case the wedge fork (6) moves towards the first direction.