DE102008002769A1 - Helical bevel gear, particularly worm gear for electrical power steering for motor vehicle, has screw bevel connected with drive shaft of electrical driving motor and screw bevel is arranged in transmission case - Google Patents

Abstract

The helical bevel gear (100) has a screw bevel (103) connected with a drive shaft of an electrical driving motor. The screw bevel is arranged in a transmission case and stands in contact with a bevel gear (104). A preload device is provided for improving the contact to impinge the screw bevel radially with a prestressing force. A tiltably arranged sleeve (120) is provided in the transmission case in which the screw bevel is stored. The preload device directly acts on the sleeve.

Description

The The invention relates to a helical gear, in particular a worm gear, according to the preamble of claim 1 and a equipped electric power steering system, according to the Preamble of the independent claim.

From the DE 101 61 715 A1 a generic helical gear in the configuration of a worm gear for use in an electric power steering system is known. The 1 shows the known Schraubradgetriebe 1 that in a housing 2 is arranged and a snail 3 and a worm wheel 4 having, wherein the screw 3 by means of a coupling 8th with the one in a warehouse 11 mounted drive shaft 9 an electric drive motor 10 connected is. In the construction shown is the worm 3 pivotable perpendicular to the axis of rotation and in a swivel or self-aligning bearing 5 stored, which can be achieved to keep the teeth clearance constant throughout the life of the transmission. For this purpose, the snail 3 acted upon radially with a biasing force and permanently against the teeth of the worm wheel 4 or helical wheel pressed. In the construction shown a biasing device is provided for this purpose, which is a biasing spring 13 and a printing device 12 has a play-free engagement between the screw 3 and the worm wheel 4 and to compensate for the operating forces occurring. The printing device 12 can z. B. with a hydraulic device 14 and a pressure piece actuated therefrom 15 Be provided on the local camp 16 or the snail 3 itself acts. Thus, the over the lifetime adjusting wear can be compensated automatically, so that the backlash does not increase as possible and vibration noise can be avoided. However, it has been found in such a known construction that also on the pivotable bearing 5 Noises can occur that can only be eliminated to a limited extent by using an expensive special bearing.

Of the The invention is therefore based on the object, the pivotal movement of the Schraubritzels or the worm perpendicular to the axis of rotation and in the direction of the screw or worm wheel overcoming to allow the above-mentioned disadvantages constructive.

Solved the object is achieved by a Schraubradgetriebe, in particular worm gear, with the features of claim 1.

Therefore is a Schraubrad- or worm gear for an electrical Power steering proposed, which is characterized in that the transmission housing a pivotally mounted sleeve is provided, in which the screw pinion or the worm stored is, with the biasing device directly on the sleeve acts.

By Such a designed Schraubrad- or worm gear can in particular the use of a special pivot bearing or self-aligning bearing for a pivotal mounting of Schraubritzels or the screw omitted. The storage of the sleeve can be relatively simple and inexpensive, B. by journals, can be realized. Overall, a result cost-effective to manufacture and easy to assemble to be handled construction of a low-noise helical or worm gear.

According to the invention also proposed an electric power steering system equipped with it.

advantageous Further developments and embodiments of the invention will become apparent the dependent claims and from the below with reference to the drawing schematically illustrated embodiments, wherein:

2 shows a first cross-sectional view of the Schraubradgetriebes invention;

3 a cross-sectional view of another embodiment of the helical gear according to the invention;

4a , B further cross-sectional views of the embodiments according to 2 and 3 (along a sectional area EE);

5a , B further cross-sectional views of the embodiments according to 2 and 3 (along a sectional area BB) shows; and

6 an exploded view of the Schraubradgetriebes invention shows.

The in the 2 - 6 illustrated embodiments show an example of a worm gear designed according to the invention. However, the invention is not limited to worm gears in particular, but can be generally applied to any type of Schraubradgetrieben.

As can be seen from these figures, the Schraubradgetriebe 100 a connectable to a drive shaft of an electric drive motor screw 103 on that in a gearbox 102 is arranged and with a worm wheel 104 engaged. To improve the engagement is a biasing device 112 provided, which the snail 103 radially with a leader acted upon force. According to the invention, the biasing device acts 112 not on the snail 103 itself, but on one in the gearbox 102 pivotally mounted sleeve 120 in which the snail 103 is stored.

Under storage here is the restriction of the degrees of freedom of the screw 103 understood by a fixed bearing as well as a floating bearing, so that the snail 103 can only rotate around its axis of rotation. The sleeve 120 Here is rotatably connected via journal with the gear housing, wherein the connection is realized so that the sleeve 120 in the direction of the worm wheel 104 or wrench can pivot. The snail 103 and the sleeve 120 thus form a pivotally mounted screw assembly. Due to the illustrated fixation of the screw assembly in the transmission housing 102 is no further bearing point of the sleeve 120 required.

The pretensioner 112 or adjusting device, whose spring force directly on the sleeve 120 acts, ensures that the screw assembly always towards the worm wheel 104 or helical wheel is pressed.

There the worm or helical gear assembly is preferably made by elastomeric or plastic plain bearing decoupled from the gear housing is, a further noise reduction can be achieved.

through the generated biasing force can the worm with the worm wheel kept free of play while operating staff preferably compensated by a hydraulic damping become. Thus, it is possible to have a small preload force to choose and at the same time by the hydraulic damping To achieve such a damping that easily high Operating forces can be intercepted.

Consequently Not only can rattling and vibration noises but can also be a jamming or jamming of the Worm gear by a too large extent certain Materials are reliably avoided. The shown Construction achieves advantageously a backlash-free gearing engagement of the worm gear and a compensation of occurring high operating forces.

Also if the invention exemplifies trained according to the invention Worm gears has been described, so is the invention not limited to worm gear in particular, but can generally be applied to any type of helical gearboxes.

1

helical gears in the form of a worm gear (according to the prior art) with:

2

casing

3

slug

4

worm

5

swiveling camp

6

Four point contact bearings

7

swivel

8th

clutch

9

drive shaft

10

drive motor

11

camp (Drive shaft)

12

hydraulic print Setup

13

biasing spring

14

hydraulic device

15

Pressure piece

16

camp (Slug)

100

helical gears or worm gear) (embodiment of the invention) With:

102

casing

103

slug (Sprockets)

104

worm (Helical gear)

112

print Setup

116

camp (Slug)

120

shell

121

pivot

122

camp (Slug)

123

camp (Sleeve)

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10161715 A1 [0002]

Claims (7)

Helical gear ( 100 ) for an electric power steering system, wherein the Schraubradgetriebe ( 100 ) connectable to a drive shaft of an electric drive motor screw pinion ( 103 ), which in a transmission housing ( 102 ) is arranged and with a helical gear ( 104 ), wherein to improve the engagement, a pretensioning device ( 112 ) is provided to the screw pinion ( 103 ) act upon radially with a biasing force, characterized in that in the transmission housing ( 102 ) a pivotally mounted sleeve ( 120 ) is provided, in which the sprocket ( 103 ) is mounted, wherein the biasing device ( 112 ) directly on the sleeve ( 120 ) acts. Helical gear ( 100 ) according to claim 1, characterized in that the sleeve ( 120 ) via trunnions ( 121 ) with the transmission housing ( 102 ) is pivotally connected. Helical gear ( 100 ) according to claim 1 or 2, characterized in that in the sleeve ( 120 ) the sprocket ( 103 ) by means of a fixed storage ( 116 ) and / or a floating bearing ( 122 ) is mounted rotatably only about its axis of rotation. Helical gear ( 100 ) according to one of the preceding claims, characterized in that the Schraubradgetriebe as worm gear ( 100 ), wherein the helical gear as worm wheel ( 104 ) is formed and the screw pinion as a screw ( 103 ) is formed, which with the worm wheel ( 104 ) and in which in the transmission housing ( 102 ) pivotally mounted sleeve ( 120 ) is rotatably mounted. Schraubradgetriebe, in particular worm gear ( 100 ), according to one of the preceding claims, characterized in that the pretensioning device ( 112 ) is provided with a spring element and / or with an electromagnetic actuator and / or with a pressure device, in particular a hydraulic pressure device. Schraubradgetriebe, in particular worm gear ( 100 ), according to one of the preceding claims, characterized in that the screw pinion or the screw ( 103 ) and the sleeve ( 120 ) form a screw assembly, which by means of a storage ( 123 ), in particular a noise-damping elastomer and / or plastic plain bearing, and / or an axially preloaded roller bearing, rotatable about an axis, in the transmission housing (in 102 ) is arranged. Electric power steering system for motor vehicles with a helical gear, in particular worm gear ( 100 ), which is connectable to a drive shaft of an electric drive motor screw pinion, in particular a screw ( 103 ), which in a transmission housing ( 102 ) is arranged and with a helical gear, in particular worm wheel ( 104 ), wherein to improve the engagement, a biasing device ( 112 ) is provided to the screw pinion or the screw ( 103 ) act upon radially with a biasing force, characterized in that in the transmission housing ( 102 ) a pivotally mounted sleeve ( 120 ) is provided, in which the screw pinion or the screw ( 103 ) is mounted, wherein the biasing device ( 112 ) directly on the sleeve ( 120 ) acts.