CN114643910A

CN114643910A - Device for adjusting a seat part, in particular a backrest, in a vehicle

Info

Publication number: CN114643910A
Application number: CN202111540981.5A
Authority: CN
Inventors: A·迈尔; J·芒什; J·施米德; K·沃尔施莱格尔; M·凯特勒
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-12-17
Filing date: 2021-12-16
Publication date: 2022-06-21
Also published as: DE102020216186A1

Abstract

The invention relates to a device (10) for adjusting a seat part (12), in particular a backrest (14), in a vehicle, having a first gear stage (15) which consists of a worm (20) and a worm wheel (22) which meshes with the worm (20); the device has a second gear stage (16) which is composed of an involute pinion (24) and an output wheel (26) which meshes with the involute pinion (24), wherein a worm wheel (22) which is inserted into the worm (20) is coupled in a rotationally fixed manner to the involute pinion (24), and the output wheel (26) has a hollow shaft contour (28) as an output element (29), into which a corresponding contour shaft (30) can be inserted in a form-fitting manner, and the hollow shaft contour (28) is formed eccentrically with respect to an axis of rotation (32) of the output wheel (26).

Description

Device for adjusting a seat part, in particular a backrest, in a vehicle

Technical Field

The invention relates to a device for adjusting a seat part, in particular a backrest, in a vehicle according to the type of the independent claim.

Background

DE 60208158T 2 describes an actuating drive for adjusting an exterior mirror of a motor vehicle, which actuating drive comprises a three-stage transmission, by means of which the actuating movement of an electric drive motor is transmitted to the exterior mirror. As a first stage, the gear mechanism comprises a worm which is arranged on the rotor shaft of the electric drive motor and a worm wheel which is in engagement with the worm. The second stage consists of an involute pinion (evoloid dritzel) and an intermediate wheel in engagement with the involute pinion. The involute pinion is designed in one piece with the worm gear. The third stage consists of a pinion and an output wheel which is in tabling engagement with the pinion and forms an internal gear. The connection between the intermediate wheel and the pinion is formed by a slip coupling. The drive wheel is designed in one piece with the mirror adjustment element.

Disclosure of Invention

The advantage of the device according to the invention with the features of the independent claims is that by the eccentric configuration of the hollow shaft profile (hohlwellenpenprofiler) in the output wheel, the profile shaft directly executes an eccentric rotational movement, with which it drives the seat part. The gear mechanism of the adjusting device comprises two gear stages connected in series, by means of which the rotational speed of the preferably electric drive motor is reduced to the seat part. The first gear stage consists of a worm and a worm wheel which meshes with the worm, wherein the worm is usually connected in a rotationally fixed manner to a rotor shaft of the drive motor. The second gear stage consists of an involute pinion and an output wheel which meshes with the involute pinion, wherein the output wheel directly or indirectly drives the movable component via a contour shaft. The coupling between the first and second gear stages is achieved by a rotationally fixed connection of the worm gear (which is part of the first gear stage) to the involute pinion (which is part of the second gear stage). A particular advantage results from the very compact design of the multi-stage transmission according to the invention in combination with the relatively high transmissible torques. This enables the use of a smaller and less expensive electric drive motor.

Advantageous refinements and improvements of the features specified in the dependent claims result from the measures cited in the dependent claims. By transmitting the drive torque via the involute gear to the hollow shaft profile, the profile shaft can transmit the drive torque simultaneously to two axially opposite seat parts. In this case, the continuous contour shaft engages directly in the receptacle of the seat hinge, so that, for example, the backrest can be tilted relative to the seat surface.

The output wheel is directly supported radially and in particular also axially in the transmission housing by means of a formed axial bearing block (Lagerstutze). Inside the bearing seat, the hollow shaft contour is shaped with a certain eccentricity relative to the rotational axis of the output wheel, so that a contour shaft which passes completely through the hollow shaft contour performs an eccentric rotational movement.

In order to adjust the backrest by means of a planetary or eccentric gear mechanism arranged in the backrest fitting, it is particularly advantageous if the contour shaft is rotated with an eccentricity of 1.0 mm to 3.0 mm, in particular 1.5 mm to 2.0 mm, relative to the axis of rotation of the output wheel. The contour shaft can thereby transmit the eccentric movement directly to the eccentric or planetary gear of the backrest fitting without unnecessary friction losses or deformations, so that the efficiency of the torque transmission is improved.

According to an advantageous further development, it is provided that the number of pinion teeth of the involute pinion is at most five. The number of pinion teeth is therefore in the range of three to five, wherein an involute pinion with exactly four pinion teeth is preferably used.

The worm wheel and the involute pinion are preferably embodied as a common component which forms an intermediate wheel, wherein the intermediate wheel is advantageously supported with its bore on a metal pin. In this case, the metal pins can be pressed or injected very cost-effectively into the housing shell of the gear mechanism housing and supported in the corresponding housing cover by means of pin bearings. The involute pinion can be injection molded from plastic in one piece with the worm gear. Alternatively, the involute pinion can be made of metal, preferably as a sintered component, and injection-molded as an insert during the injection molding of the worm gear.

The adjusting device is particularly suitable for the small installation space that is available when adjusting the backrest in a motor vehicle. The combination of the involute gear stage and the eccentric configuration of the hollow shaft contour in the output wheel makes it possible to reduce the installation space and weight considerably in comparison with conventional actuating drives. Furthermore, the noise formation of the interference is thereby effectively suppressed.

By selecting the parameters according to the invention for the involute gear according to DIN 3960, the strength of the involute pinion can also be increased significantly if it is supported on a metal pin. At the same time, the friction properties of the tooth pairs between the involute pinion and the output wheel are optimized with regard to wear and noise development. The involute pinion therefore advantageously has a tooth root height h greater than 0.9, preferably of about 0.9 to 1.1_fP1. The involute pinion has a tooth crest factor h of 0.3 to 0.8, preferably approximately 0.4 to 0.6_aP1And (4) forming. The output wheel has a tooth crest factor h of 0.3 to 0.6, preferably 0.4 to 0.5_aP2Wherein the tooth root height coefficient h of the output wheel_fP2Advantageously greater than 1.1. The output wheel has a positive profile modification (profiversebusing) x2 greater than zero, preferably from +0.7 to + 1.0. Also, the involute pinion has a positive profile modification of 0.9 to 1.3, preferably 0.9 to 1.1x1。

The seat back adjustment device according to the invention for adjusting the seat back by direct drive of an eccentric or planetary gear mechanism is particularly compact and very low-noise in the opposite seat back fitting (Sitzlehnenbechl ä ge). In this case, however, the involute toothing (evolvententeverzhahnng) is designed mechanically stable for the transmission of high torques, wherein a contour shaft which is mounted eccentrically in the output wheel interacts in a friction-optimized manner with an eccentric or planetary gear mechanism of the seat back fitting.

Drawings

Further advantages and suitable embodiments can be gathered from the further claims, the description of the figures and the drawings. In which is shown:

fig. 1 shows a perspective view of an adjusting device, with a single illustration of the components of the transmission,

FIG. 2 shows another embodiment of a seat back adjustment device incorporated into a vehicle seat, and

fig. 3 schematically shows a further gear unit with corresponding gear parameters.

Detailed Description

Fig. 1 shows a gear unit 18 for adjusting a movable component 11 in a vehicle, for example for adjusting a seat component 12. The gear unit 18 is designed in two stages, having a first gear stage designed as a worm gear 15 and a second gear stage designed as an involute gear 16. The worm gear 15 is composed of a worm 20 and a worm wheel 22, the worm 20 being connected in a rotationally fixed manner to a rotor shaft 52 of an electric drive motor 50, the worm wheel 22 being fitted into the worm 20. The first axis of rotation 21 of the worm 20 is arranged here substantially perpendicularly to the rotor axis 51 of the rotor shaft 52. The involute transmission 16 includes an involute pinion 24 and an output wheel 26 that meshes with the involute pinion 24, wherein the involute pinion 24 is disposed on the first rotational axis 21 of the worm gear 22. The output wheel 26 is arranged on an output wheel axis 32 which is offset parallel to the first axis of rotation 21. The worm wheel 22 and the involute pinion 24 are embodied as a common structural unit and together form an intermediate wheel 23, wherein the first axes of rotation 21 of the worm wheel 22 and the involute pinion 24 coincide. Preferably, the involute pinion 24 is made in one piece with the worm wheel 22 as the intermediate wheel 23. The involute pinion 24 and the worm wheel 22 can be produced by plastic injection molding or the involute pinion 24 can be injection molded as a metallic, in particular sintered, insert with the worm wheel 22 made of plastic.

As shown in fig. 1, the involute pinion gear 24 has preferably four pinion teeth 25. The number of pinion teeth 25 is between three and five. The intermediate wheel 23 has a through-opening 44 along the first axis of rotation 21, into which a rotationally fixed metal pin 42 engages. The metal pins 42 are, for example, pressed into the gear housing 38 or injection molded as inserts. The gear housing 38 is preferably produced as a plastic injection-molded part and has a housing cover 39 which is closed with a housing cover 40. Preferably, a metal pin 42 is fixed in the housing shell 39 in a rotationally fixed manner, onto which the intermediate wheel 23 is then slipped. After the complete assembly of the gear unit 18 in the assembly direction of the first rotational axis 21, the gear housing cover 40 is engaged in the assembly direction of the first rotational axis 21, wherein the free ends 43 of the metal pins 42 engage in corresponding pin bearings 45 in the gear housing cover 40.

A hollow shaft contour 28 is formed in the output wheel 26, which serves as an output element 29. The output wheels 26 each have a cylindrical bearing seat 34 formed in one piece along an output wheel axis 32, which each engage axially in a corresponding bearing receptacle 36 in the gear housing 30. The output wheel 26 is preferably made of plastic together with a bearing block 34, which is directly mounted radially in a bearing sleeve 37 of plastic of the bearing receptacle 36. Here, the bearing block 34 preferably passes through the gear housing 38 on both sides along the output wheel axis 32. The hollow shaft contour 28 is formed radially inside the bearing seat 34. The longitudinal axis 27 of the hollow shaft contour 28 does not coincide with the output wheel axis 32. More precisely, the longitudinal axis 27 is arranged eccentrically with respect to the output wheel axis 32, wherein the eccentricity 46 is in particular 1.0 to 2.0 mm. This means that the hollow shaft contour 20 is not designed concentrically with respect to the bearing seat 34, but rather is designed radially offset with respect to the output wheel axis 32. Hollow shaft contour 28 is designed, for example, as a multi-tooth inner contour 47 or approximately as an inner quadrilateral (innevierkant) 48, as is shown in fig. 2 and 3.

Fig. 2 shows a cut-out of a vehicle seat into which the electric adjustment device 10 for the backrest 14 is inserted. The adjusting device 10 has an electric motor 50 to which the gear mechanism housing 38 is flanged, which accommodates the gear mechanism unit 18. According to fig. 1, the gear unit 18 has a first worm gear 15 and a second involute gear 16. A metal pin 42 for supporting the intermediate wheel 23 is fixed in the gear housing 38, in particular in the gear housing cover 39. On the transmission housing cover 40, pin receptacles 45 are formed on the inside thereof, in which the pins 42 are supported after the transmission housing cover 40 has been assembled. The bearing receptacle 36 for the bearing seat 34 of the output wheel 26 is designed as a sleeve-shaped axial bore 37 in a transmission housing cover 40 and a transmission housing cover 39. The bearing blocks 34 engage axially into these bores 37 in order to support the output wheel 26 radially and in particular also axially. Radially inside the bearing seat 34, eccentrically thereto, a hollow shaft contour 28, which is designed here as an inner quadrilateral 48, is formed. A profile shaft 30, which is here a square profile, is inserted into the hollow shaft profile 28 and projects axially on both sides from a bearing seat 34 of the output wheel 26. By the eccentric arrangement of the longitudinal axis 27 of the hollow shaft contour 28 relative to the output wheel axis 32, the contour shaft 30 executes an eccentric movement with an eccentricity 46 about the output wheel axis 32. If the output wheel 26 is set in rotation by the involute drive 16, the torque is transmitted to the component 11 to be adjusted via a contour shaft 30 connected to the output wheel 26 in a form-fitting manner. In the seat back adjustment device 80, both free ends of the contour shaft 30 are fitted into corresponding shaft receiving portions of the seat back fitting 13, which form hinge portions between the backrest 14 and the seat surface 55. The shaft receptacles are preferably arranged on both sides in a corresponding planetary or eccentric gear of the seat back fitting 13, which are driven by the eccentric movement of the contour shaft 30 in order to rotate the seat back 14 relative to the seat surface 55. The drive motor 50 and the gear housing 38 are preferably fastened to the backrest 14, while the shaft receptacle for the contour shaft 30 is fastened to the seat surface 55.

Fig. 3 shows a further embodiment of a gear unit 18 with a worm gear 15 and an involute gear 16 following it. The involute pinion 24 is rotatably supported on the pin 42 together with the worm wheel 22. The involute pinion 24 has pinion teeth 25 with a tooth root height h according to DIN 3960 standard in 1987_fP1(62) And tooth crest height coefficient h_aP1(61) And a positive profile modification factor x1 (63). Accordingly, the corresponding toothing of the output wheel 26 has a root height h_fP2(62) And tooth crest height coefficient h_aP2(61) And a positive profile modification factor x2 (63). The involute pinion 24 is mechanically stable in particular in the tooth base region of the pinion teeth 25, so that a hole 44 for the standing pin 42 can be formed centrally. The longitudinal axis 27 of the hollow shaft contour 28 of the output wheel 26 is again arranged eccentrically offset with respect to the output wheel axis 32 by an eccentricity 46. The profile shaft 30, which is inserted axially into the hollow shaft profile 28, thereby executes an eccentric rotational movement. The hollow shaft contour 28 is designed here, for example, as a quadrangular inner contour 48, into which the outer quadrangular contour shaft 30 is inserted according to fig. 2.

Claims

1. A device (10) for adjusting a seat part (12), in particular a backrest (14), in a vehicle has a first gear stage (15) which consists of a worm (20) and a worm wheel (22) which meshes with the worm (20); the device has a second gear stage (16) which is composed of an involute pinion (24) and an output wheel (26) which meshes with the involute pinion (24), wherein a worm wheel (22) which is inserted into the worm (20) is coupled to the involute pinion (24) in a rotationally fixed manner, and the output wheel (26) has a hollow shaft contour (28) as an output element (29), into which a corresponding contour shaft (30) can be inserted in a form-fitting manner, and the hollow shaft contour (28) is formed eccentrically with respect to the rotational axis (32) of the output wheel (26).

2. The device according to claim 1, characterized in that the hollow shaft contour (28) passes completely through the output wheel (26) along the rotational axis (32) of the output wheel (26) and the contour shaft (30) extends axially from the output wheel (26) in two opposite directions (8) and fits into two opposite seat parts (12).

3. Device according to claim 1 or 2, characterized in that two opposite axial bearing seats (34) are formed on the output wheel (26), which fit into corresponding bearing receptacles (36) in a transmission housing (38) in order to rotatably support the output wheel (26) on the axis of rotation (32), and in that the hollow shaft contour (30) is formed eccentrically in the bearing seats (34) with respect to the bearing seats (34), and in that the hollow shaft contour (30) passes completely through the bearing seats (34) in the axial direction (8).

4. The device according to one of the preceding claims, characterized in that the longitudinal axis (27) of the hollow shaft contour (28) is arranged radially spaced from the rotational axis (32) of the output wheel (26) by 1.0 to 3.0 mm, in particular by approximately 1.5 mm.

5. Device according to any one of the preceding claims, characterized in that the involute pinion (24) has at least three and at most five, in particular exactly four, pinion teeth (25).

6. The device according to one of claims 1 to 6, characterized in that the worm wheel (22) and the involute pinion (24) form an intermediate wheel (23), and the intermediate wheel (23) is rotatably mounted by means of a bore (44) on a metal pin (42) which is pressed or injected into a housing cover (39) of the gear housing (38) and is supported in particular by means of a pin bearing (45) in a cover (40) of the gear housing.

7. The device according to one of the preceding claims, characterized in that the contour shafts (30) are respectively fitted into two opposite seat back fittings (13) as seat parts (12), wherein an eccentric or planetary gear is respectively arranged in the seat back fittings (13), which is driven by an eccentrically supported contour shaft (30) in order to adjust the backrest (14).

8. Device according to any of the preceding claims, characterized in that the involute pinion (24) has a tooth root height h greater than 0.9, preferably between 0.9 and 1.1_fP1（62）。

9. Device according to any one of the preceding claims, characterized in that said involute pinion (24) has a crest factor h of 0.3 to 0.8, preferably of about 0.4 to 0.6_aP1（61）。

10. Device according to any one of the preceding claims, characterized in that the output wheel (26) has a tooth crest factor h of 0.3 to 0.6, preferably 0.4 to 0.5_aP2(65) And in particular having a root height h of greater than 1.1_fP2（66）。

11. Device according to any one of the preceding claims, characterized in that the output wheel (26) has a profile modification factor x of more than 0, preferably of +0.7 to +1.0₂(67) And in particular the involute pinion (24) has a profile modification of 0.9 to 1.3, preferably 0.9 to 1.1Coefficient x₁（63）。

12. Seat back adjustment device (80) having a device (10) for adjusting a seat part (12) according to one of the preceding claims, characterized in that the seat part (12) is designed as a backrest (14) on which two opposite seat backrest fittings (13) are arranged, wherein an eccentric drive or a planetary drive is arranged in each case in the seat back fitting (13), the eccentric or planetary gear mechanism is driven by a contour shaft (30) eccentrically mounted in an output wheel (26) in order to adjust the backrest (14) relative to a seat surface (55), and in particular a drive motor (50) is fixedly secured to the backrest (14) together with the gear housing (38) and rotates together with the backrest (14) during adjustment.