Drive device for a vehicle interior fitting, adjustment device and headrest

Abstract

Drive device (10) for a vehicle interior equipment component (13) comprising an adjustment motor (16) and a control unit (17), wherein the adjustment motor (16) is controlled by means of the control unit (17), wherein a sensor is associated with the drive device (10) with the adjustment motor (16) and a transmission (36), wherein a pulse rate modifier (18) is interposed between the adjustment motor (16) and the control unit (17), which modifies a pulse rate (P) received from the adjustment motor (16). Motor ) modified such that they are within a pulse rate (P) range that can be processed by the control unit (17). Steuergerät Max ) and wherein the pulse rate modifier (18) is a modified value of the pulse rate (P Reduz) forwards to the control unit (17), characterized in that the pulse rate modifier (18) comprises a mechanical transmission (36) whereby the speed of the adjusting motor (16) can be modified by the transmission (36) such that it lies within a value range of the pulse rate to be processed by the control unit (17), wherein a sensor is assigned to a transmission stage of the transmission (36) which measures the speed (n Getriebe ) which is in a specific gear ratio to the rotational speed (n Motor ) of the adjustment motor (16) in the gear stage and sends a correlating pulse rate to the control unit (17).

Description

[0001] The invention relates to a drive device for a vehicle interior component. The vehicle is, for example, a land, air, or water vehicle.

[0002] Such a drive device is known from prior use. Equipment components, such as height-adjustable headrests of vehicle seats, are equipped with an electric adjustment motor that moves the headrest section relative to the backrest, e.g., up or down. The adjustment motor is controlled by a control unit, e.g., the seat control unit, according to the desired adjustment range and direction.

[0003] The seat control unit uses a signal from the adjustment motor, which is provided to it in the form of a pulse rate corresponding to the motor's rotational speed. For this purpose, the adjustment motor includes a sensor that detects the rotational speed and converts it into a pulse rate corresponding to that speed. This could be, for example, a Hall sensor.

[0004] The design of the accessory requires that the adjustment motor be compact, lightweight, and / or have a low noise level and / or minimal noise variation. The noise level of the adjustment motor is influenced, for example, by the load acting upon it. This load depends, for instance, on the direction of adjustment. Different loads act on the adjustment motor depending on whether the accessory is adjusted upwards (against gravity) or downwards (in the direction of gravity). For example, when a headrest is adjusted against gravity, the load on the adjustment motor is greater. This generally results in a different noise level than when the headrest is adjusted downwards (in the direction of gravity).

[0005] Similarly, higher loads, caused by increased friction in the guides of the component or by lower temperatures, lead to a higher noise level from the adjustment motor. If conditions change across the adjustment range, fluctuations in the noise level can occur during operation of the adjustment motor.

[0006] It is generally accepted that load fluctuations have a greater impact on running noise at high operating speeds than at low operating speeds.

[0007] To meet the requirements for low weight and small size of the component, small adjustment motors are used. However, these must be operated at higher speeds. Load fluctuations then lead to greater noise fluctuations compared to adjustment motors with lower operating speeds.

[0008] The required motor power depends on the maximum load possible within the system. This is determined by the existing friction coefficients of the guides, the influence of the headrest mass, and the influence of temperature changes.

[0009] In small adjustment motors, this power is generally generated via high speeds, so that with variable loads, the operating speed is sometimes in a range where the pulse rate transmitted by a sensor can no longer be processed by standard control units and leads to failure of the control or drive system.

[0010] German patent DE 10 2015 000 937 A1 concerns a drive device for a vehicle interior accessory. To meet the requirements for low weight and small size of the accessory, small actuator motors with high speeds are used, where the pulse rate transmitted by a sensor cannot be processed by standard control units and leads to failure of the control or drive system.

[0011] The invention solves the problem by inserting a pulse rate modifier between the sensor of the adjustment motor and the control unit.

[0012] As an example of such a pulse rate modifier, DE 10 2015 000 937 A1 discloses in paragraph 15 an electronic component, e.g. a frequency divider.

[0013] Alternatively, paragraph 16 proposes a software solution as a pulse rate modifier, which is processed by a controller.

[0014] German patent application DE 10 2008 036 644 A1 relates to an adjustment device for a motor vehicle seat with an electric motor and a gearbox connected to it. The objective of DE 10 2008 036 644 A1 was to reduce the weight and volume of the adjustment device. This is achieved by using a smaller electric motor with a high speed. Paragraph 8 of DE 10 2008 036 644 A1 mentions that the small, high-speed motors used require an additional gearbox stage, which can be constructed cost-effectively.

[0015] A pulse rate modification with regard to the pulse rate to be processed by a controller is not mentioned in DE 10 2008 036 644 A1.

[0016] The object of the invention was to modify the signals provided to the control unit by a sensor on a drive device for a vehicle interior accessory in such a way that their pulse rate lies within a range that can be processed by commercially available control units for all load ranges. In particular, the drive device comprises a high-speed adjustment motor.

[0017] The problem was initially solved by a drive device having the features of claim 1.

[0018] The drive unit is designed for adjusting a vehicle interior trim component relative to a mounting bracket. The drive unit comprises an adjustment motor, a control unit, and an adjustment mechanism that translates the motor's movement into movement of the trim component. The control unit regulates the speed and direction of rotation of the adjustment motor. The drive unit, which includes a high-speed adjustment motor, is equipped with a sensor that transmits a pulse rate corresponding to the rotational speed to the control unit from a gear stage of a transmission. The transmission of control data from the control unit to the adjustment motor and the transmission of the pulse rate from the drive unit's sensor to the control unit occur via wired connections or wirelessly using standard wireless technologies such as Wi-Fi, Bluetooth, etc.

[0019] According to the invention, a pulse rate modifier in the form of a mechanical transmission is associated with the adjustment motor. The transmission is part of the drive device and modifies the speed of the adjustment motor such that it lies within a pulse rate range that can be processed by the control unit. In other words, the adjustment motor is connected to a transmission that modifies the speed of the output stage of the transmission. The modified speed is detected by a sensor at a transmission stage, such as a gear, converted into a pulse rate corresponding to the speed, and sent to the control unit.

[0020] In this way, adjustment motors can be controlled by commercially available control units, whereby a pulse rate corresponding to the maximum speed of the adjustment motor can be greater or less than the pulse rate to be processed by the control unit.

[0021] The advantage of mechanical frequency division is the ability to adapt the pulse rate or period to the mechanical requirements. Through the interplay of the gear ratio in the individual gear stages and the possibility, due to the larger dimensions of the gear shaft, of using multiple pole pairs for sensing per revolution, a more precise determination of the output shaft's rotational position is possible.

[0022] To clarify: When sensing on the motor shaft, a ring magnet with one pole pair is usually used, while on the gearbox shaft, due to the larger dimensions of the component, a ring magnet with 6 pole pairs can be used.

[0023] The pulse rate of the adjustment motor can be modified, for example, exclusively by the gearbox or by parts of the gearbox. For instance, the pulse rate modification can be performed by two interacting gear teeth within the gearbox.

[0024] Additionally, the pulse rate modifier can also include an electronic component that modifies the pulse rate in addition to the transmission. The pulse rate modifier then sends the modified pulse rate value to the control unit.

[0025] If, according to one embodiment, the pulse rate modifier additionally comprises an electronic component, this component is, in particular, a commercially available electronic component. The electronic component is, for example, a frequency divider. Frequency dividers are commercially available electronic components that are inexpensive and readily available on the market. With the frequency divider, it is easy to reduce the pulse rate, for example, by halving it, in accordance with the motor speed. According to an alternative, however, the electronic component can also apply a different function to the pulse rate. In this way, the pulse rate modifier can effect a reduction or an increase in the pulse rate.

[0026] The sensor associated with the drive device can, for example, be a Hall sensor. However, any other suitable sensor is also possible. The number of signals output by the sensor depends on the product of the gear ratio and the number of pole pairs of the magnet in contact with the drive. A Hall sensor carrying a current provides an output voltage that is proportional to the product of the magnetic flux density and the current when placed in the magnetic field of a magnet. Different magnets can have different numbers of pole pairs.

[0027] According to one embodiment, the sensor can be selectively positioned on one of several parts of the gearbox. In this way, the sensor's position allows for the control of its sensitivity to mechanical influences and its degree of accuracy. For example, the sensor can be selectively positioned on a first, faster-rotating part of the gearbox or on a second, slower-rotating part. Positioning it on the second, slower-rotating part increases the signal period, thus reducing sensitivity. Conversely, positioning it on the first, faster-rotating part reduces the signal period, thereby increasing sensitivity.

[0028] The period can also be influenced by varying the number of pole pairs of the magnet. A larger number of pole pairs decreases the period of the measurement signal, and a smaller number of pole pairs, e.g., 1, increases the period.

[0029] The gearbox can be housed in a casing, for example. The motor can also be housed in that casing.

[0030] The invention also relates to an adjustment device comprising a vehicle interior fitting and a holding part, wherein the fitting is movable relative to the holding part by means of the drive device according to the invention.

[0031] Furthermore, the invention relates to a headrest. The headrest comprises a head section which is mounted to the backrest of the vehicle seat by at least one support rod. The head section is adjustable relative to the backrest. The head section and the backrest form the adjustment device according to the invention, wherein the head section is a vehicle interior fitting and the backrest is a retaining element. The head section is movable relative to the backrest by means of the drive device according to the invention. Support rods are associated with the head section. For example, the head section is adjustable relative to support rods fixed to the backrest. According to an alternative, the support rods are fixed to the head section and are movable relative to the backrest.

[0032] Further advantages become apparent from an exemplary embodiment shown schematically in the figures. They show: Fig. 1 a vehicle seat with a backrest and with an electrically height-adjustable headrest comprising the drive device according to the invention, Fig. 2. A perspective view of the headrest from the front, whereby the head support plate is not shown for the sake of clarity. Fig. 3 a perspective view of the housing with drive motor and gearbox as well as the drive spindle, Fig. 4 a section view according to section line IV - IV in Fig. 5, Fig. 5 a top view of the engine housing, with the engine housing cover not shown, Fig. 6 a section view according to section line VI - VI in Fig. 5, and Fig. 7 a sectional view of the spindle nut.

[0033] A drive device as a whole is designated by reference numeral 10 in the figure.

[0034] In the present embodiment, the drive device 10 is provided for controlling a headrest 11 adjustable in directions z1 and z2, which is mounted on the backrest 12 of a vehicle seat 13. The headrest 11 comprises a head section 14 and support rods 15. The head section 14 is held by the support rods 15. The support rods 15 are themselves mounted in a bearing fixed to the backrest. The head section 14 is mounted so that it can be moved relative to the backrest 12 in directions z1 and z2 by means of an electric adjustment motor 16. For example, the head section 14 can be moved relative to the support rods 15, while the support rods 15 can be mounted, for example, so that they are fixed relative to the backrest 12.

[0035] According to an alternative design, the support rods 15 could also be moved relative to the backrest-fixed bearings by means of the adjustment motor, with the head section 14 being mounted immovably relative to the support rods 15.

[0036] The adjustment motor 16 is controlled by a seat control unit 17. As indicated by lines 19 and 20, the adjustment motor 16 and the seat control unit 17 are connected by data lines, enabling data transmission. This can be done, for example, via cable, radio, Wi-Fi, etc. The seat control unit 17 can control the adjustment motor 16 using data lines 19 and 20. To control the adjustment motor 16, the seat control unit 17 requires the current speed nMotor of the adjustment motor 16. A sensor is provided for this purpose, which can detect the speed n and convert it into a pulse rate P corresponding to that speed. This could be, for example, a Hall sensor.

[0037] The seat control unit 17, which only processes pulses with a half-period duration greater than 3.6 ms, can receive a maximum pulse rate PSteuergerätMax of 8333 rpm. If the adjustment motor delivered 1 pulse / revolution to the seat control unit, this meant, according to the prior art, that a maximum motor speed nMotorMax = 8333 rpm could be processed. If the seat control unit received higher pulse rates PMotor > 8333 rpm, a system failure occurred.

[0038] To meet the requirements for size, weight, and adjustment noise, it is advantageous to use a smaller adjustment motor 16 whose maximum speed nMotorMax is greater than, for example, 8333 rpm, e.g., 12000 rpm. According to the invention, the processing of the adjustment motor's speed by the seat control unit 17 is possible because a pulse rate modifier 18 in the form of a mechanical transmission is arranged between the adjustment motor 16 and the seat control unit 17. The speed nMotor is modified by the transmission, which is coupled to a motor shaft. A pulse rate PGearbox, corresponding to the speed of the transmission part nGearbox part, is sent from a sensor to the pulse rate modifier 18 via line 19.

[0039] If the pulse rate modifier 18 operates, for example, with a ratio of 1:23, the input speed at the transmission stage is reduced to 1 / 23. The number of pulses transmitted to the seat control unit 17 depends on the number of pole pairs of the ring magnet used at this stage. The pulse rate is thus determined by the gear ratio and the number of pole pairs. The reduced pulse rate value, PReduz, must be below the maximum pulse rate that the seat control unit, PSteuergerätMax, can process. With a half-period duration of the seat control unit greater than 3.6 ms, PSteuergerätMax = 8333 rpm. The reduced pulse rate value, PReduz, is transmitted to the seat control unit 17 via line 19.

[0040] In the present embodiment, the maximum pulse rate of the motor PMotorMax = 12000 rpm. With a pulse rate modifier division ratio of 2:1, the maximum pulse rate arriving at the seat control unit is PReduz = 6000 rpm. This prevents a system failure due to a pulse rate transmitted to the seat control unit 17 exceeding PSteuergerätMax. Nevertheless, a reduced pulse rate PReduz, proportional to the motor speed nMotor, is delivered to the seat control unit 17.

[0041] In Fig. Figure 2 shows a perspective view of the headrest 11. A base part 21 of the headrest 14 is adjustable relative to the support rods 15 in the directions z1 and z2. A housing 22 is fixedly connected to the base part 21. A spindle 23 is mounted to a crossbeam that connects the two support rods 15 in a rotationally secure manner. The spindle 23 is fixedly engaged with a spindle nut of a gearbox located in the housing 22. The gearbox is in Fig. 2 not discernible. The gearbox is assigned to an adjustment motor. Depending on the direction of rotation of the adjustment motor's shaft, the base part 21 is moved in the directions z1 or z2.

[0042] Furthermore, a holder adjustable in directions x1 and x2 is mounted on the base part 21, to which a head assembly (not shown) can be attached. The head assembly will not be discussed further here.

[0043] In Fig. Figure 3 shows the housing 22 and the spindle 23. The housing 22 comprises a shell 26 and a cover 27, which can be attached to the shell 26.

[0044] Fig. Figure 5 shows a top view of the shell 26 with the lid removed. The housing 22 comprises two receiving chambers 28 and 29. The body of an electric motor, hereinafter referred to as motor 30, is arranged in the receiving chamber 28. The motor 30 comprises a shaft 31 on which a worm gear 32 is mounted. The worm gear 32 engages with an external toothing 33 of the spindle nut 34. The spindle nut 34 also comprises an internal thread 35 which engages with the external thread of the spindle 23. The worm gear 32, the external toothing 33, the internal threads 35, and the spindle toothing form a gearbox 36.

[0045] In the present embodiment, the pulse rate modifier 18 is formed by the gearbox 36. A gear ratio of 1:23 exists between the worm gear 32 and the external gear 33. This means that the maximum motor speed nmotormax of 12,000 rpm is reduced, so that the spindle nut 34 has a maximum speed of 6,000 rpm. The spindle nut 34 delivers one pulse per revolution, with the pulses being detected by a sensor (not shown) and the pulse rate being transmitted to the seat control unit 17.

Claims

[1] Drive device (10) for a vehicle interior equipment component (13) comprising an adjustment motor (16) and a control unit (17), wherein the adjustment motor (16) is controlled by means of the control unit (17), wherein a sensor is associated with the drive device (10) with the adjustment motor (16) and a transmission (36), wherein a pulse rate modifier (18) is interposed between the adjustment motor (16) and the control unit (17), which modifies a pulse rate (P) received from the adjustment motor (16). Motor ) modified such that they are within a pulse rate (P) range that can be processed by the control unit (17). Steuergerät Max ) and wherein the pulse rate modifier (18) is a modified value of the pulse rate (P Reduz ) forwards to the control unit (17), characterized by, that the pulse rate modifier (18) comprises a mechanical transmission (36) whereby the speed of the adjusting motor (16) can be modified by the transmission (36) such that it lies within a value range of the pulse rate to be processed by the control unit (17), wherein a sensor is assigned to a transmission stage of the transmission (36) which measures the speed (n Getriebe ) which is in a specific gear ratio to the rotational speed (n Motor ) of the adjustment motor (16) in the gear stage and sends a correlating pulse rate to the control unit (17). [2] Drive device (10) according to claim 1, characterized by , that the pulse rate modifier (18) additionally includes an electronic component. [3] Drive device (10) according to one of claims 1 or 2, characterized by , that the gearbox (36) is arranged in a housing (22) in which a motor (30) is also accommodated. [4] Drive device (10) according to one of the preceding claims, characterized by , that the sensor is arranged on a part of at least two parts of the transmission (36) so that the sensitivity to mechanical influences and the degree of accuracy can be determined by the arrangement of the sensor. [5] Adjustment device comprising a vehicle interior equipment part (14) and a holding part (12), wherein the equipment part (14) is movable relative to the holding part (12) by means of a drive device (10) according to any one of claims 1 to 4. [6] Headrest (11) with a head section (14) which is mounted with at least one support rod (15) in at least one bearing on the backrest (12) of a vehicle seat (13), wherein the head section (14) is adjustable relative to the backrest (12), characterized by, that the headboard (14) and the backrest (12) form an adjustment device according to claim 5, wherein the headboard (14) is a fitting part (14) and the backrest (12) is a retaining part (12) and wherein the headboard (14) is movable relative to the backrest (12) by means of a drive device (10) according to one of claims 1 to 3.

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