DOUBLE-AXIAL, SHOCK-RESISTANT ROTATION RATE SENSOR WITH NESTED, LINEARLY OSCILLATING SEISMIC ELEMENTS

• US 20120279301A1
• Filed: 09/09/2010
• Published: 11/08/2012
• Est. Priority Date: 09/09/2009
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Company HG (Continental AG)
• Inventors: Günthner, Stefan, Schmid, Bernhard, Sivaraman, Ramnath, Lohmann, Jasmin
• Granted Patent: US 9,068,834 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5642 using vibrating bars or beams
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion

Abstract

A micromechanical rotation rate sensor, including a substrate whose base surface is aligned parallel to the x-y plane of a Cartesian coordinate system, with the rotation rate sensor having at least one first seismic mass and a second seismic mass which are coupled to at least one first drive device and are suspended such that the first and the second seismic masses are driven such that they are deflected in antiphase in one drive mode, with the rotation rate sensor being designed such that it can detect rotation rates about at least two mutually essentially orthogonal sensitive axes, wherein at least the second seismic mass is in the form of a frame which at least partially surrounds the first seismic mass with respect to the position on the x-y plane.

Claims

1-15. -15. (canceled)

16. A micromechanical rotation rate sensor, comprising a substrate whose base surface is aligned parallel to the x-y plane of a Cartesian coordinate system, with the rotation rate sensor having at least one first seismic mass and a second seismic mass which are coupled to at least one first drive device and are suspended such that the first and the second seismic masses are driven such that they are deflected in antiphase in one drive mode, with the rotation rate sensor being designed such that it can detect rotation rates about at least two mutually essentially orthogonal sensitive axes, wherein

at least the second seismic mass is in the form of a frame which at least partially surrounds the first seismic mass with respect to the position on the x-y plane.

17. The rotation rate sensor as claimed in claim 16, wherein the first and second seismic masses are coupled to one another by at least one first and one second coupling device such that, when a first rotation rate is detected about the first sensitive axis, they oscillate in antiphase in a first read mode, and when a second rotation rate is detected about the second sensitive axis, they likewise oscillate in antiphase in a second read mode.

18. The rotation rate sensor as claimed in claim 16, wherein the first and the second seismic masses have essentially the same mass and the rotation rate sensor is designed and the first and second seismic masses are designed and arranged such that the center of gravity of the entire rotation rate sensor remains essentially at rest with respect to the deflections of the seismic masses in the drive mode.

19. The rotation rate sensor as claimed in claim 17, wherein the rotation rate sensor has a single drive device, which drives the first and the second seismic masses of the rotation rate sensor in antiphase, for which purpose the seismic masses are suspended, and are coupled to one another by the first coupling device, in an appropriate manner.

20. The rotation rate sensor as claimed in claim 16, wherein the rotation rate sensor is designed such that the first sensitive axis lies on the x-y plane, that is to say on the base surface of the substrate, the first sensitive axis is designed to be parallel to the x axis or to the y axis, and the second sensitive axis is designed to be parallel to the z axis, that is to say at right angles to the base surface of the substrate.

21. The rotation rate sensor as claimed in claim 17, wherein the first and second seismic masses of the rotation rate sensor are designed, suspended and coupled by at least the first and second coupling devices such that they are suspended such that they can move exclusively for their respective deflections within the drive mode, for their respective deflections within the first read mode and for their respective deflections within the second read mode, and the first and second seismic masses are suspended stiffly with respect to all other deflections, that is to say all deflections in other directions and all in-phase deflections of the first and second seismic masses are suppressed.

22. The rotation rate sensor as claimed in claim 16, wherein the deflection of the first and second seismic masses in each of the at least two read modes are detected in a duplicated and differential manner, with the deflection of one of the two seismic masses in each case being detected in opposite senses by two read devices with respect to the antiphase deflection, that is to say to one seismic mass in phase and to the other seismic mass in antiphase, that is to say that the first and second seismic masses and/or the devices which are also deflected with at least one of the seismic masses are each associated with at least two read devices which are each designed and arranged such that one of these two read devices detects a capacitance increase when the other read device detects a capacitance decrease.

23. The rotation rate sensor as claimed in claim 17, wherein the first and second coupling devices each comprise at least one essentially rigid coupling beam, which is coupled by spring elements on the one hand to the first seismic mass and on the other hand to the second seismic mass, and which is suspended on at least one torsion spring element which is designed such that it allows rotational deflections of the coupling beam about one or two axes, and suppresses further rotational deflections and all translational deflections of the coupling beam.

24. The rotation rate sensor as claimed in claim 23, wherein the first coupling device is designed such that it forces antiphase deflections of the seismic masses with respect to the drive mode and suppresses in-phase deflections with respect thereto, and the first and the second coupling devices are designed such that they force antiphase deflections of the seismic masses with respect to the first and with respect to the second read modes, and suppress in-phase deflections with respect thereto, suppressing all in-phase deflections of the first and second seismic masses.

25. The rotation rate sensor as claimed in claim 23, wherein at least one coupling beam of at least one of the coupling devices is associated with two or more read devices which are designed and arranged such that they detect the rotational deflection of this coupling beam with respect to the first or second read mode in phase and in antiphase, in this case one of them in phase and the other in antiphase.

26. The rotation rate sensor as claimed in claim 25, wherein the this coupling beam is designed to be essentially c-shaped, with a base surface essentially parallel to the x-y plane in a rest state, with at least two edge segments and one connection segment, with the connection segment being connected essentially centrally to the torsion spring element such that the two edge segments can be deflected rotationally in antiphase, with this torsion spring element not being completely stiff at least with respect to a parasitic rotational deflection about the y axis, for which reason the two read devices which are associated with this coupling beam are arranged such that the centers of their longitudinal sides, essentially in the direction of the longitudinal side of the two edge segments, are each arranged with respect to the x-y alignment opposite the center of the longitudinal side of one of the edge segments, such that possible in-phase rotational deflections of the two edge segments about the y axis, which result from these two edge segments then being in an inclined position, are essentially not detected by the two read devices, with these two read devices being arranged parallel to the two edge segments in a rest state, in each case with respect to the base surfaces.

27. The rotation rate sensor as claimed in claim 16, wherein the at least one drive device is rigidly connected to the first or to the second seismic mass.

28. The rotation rate sensor as claimed in claim 16, wherein the at least one drive device is coupled to the first or to the second seismic mass by at least one spring element, such that translational coupling is provided in the drive direction between the drive unit and the first or second seismic mass, and decoupling is provided in all other at least translational directions.

29. The rotation rate sensor as claimed in claim 28, wherein the drive device is in this case additionally suspended on the substrate by at least one further spring element, with this suspension being designed to be stiff on the x-y plane and in this case at right angles to the drive direction, such that deflections of the drive device on the x-y plane in a direction other than the output-drive direction are suppressed.

30. The use of a rotation rate sensor as claimed in claim 16 in motor vehicles, for detection of the yaw rate, that is to say rotation about the vertical axis of the vehicle, and for detection of a roll rate or a pitch rate of the vehicle.