Double-axial, shock-resistant rotation rate sensor with nested, linearly oscillating seismic elements

• US 9,068,834 B2
• Filed: 09/09/2010
• Issued: 06/30/2015
• Est. Priority Date: 09/09/2009
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Gnthner, Stefan, Sivaraman, Ramnath, Schmid, Bernhard, Lohmann, Jasmin
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Shabman, Mark A
• Application Number:
  US13/391,314
• Publication Number:
  US 20120279301A1
• Time in Patent Office: 1,755 Days
• Field of Search: 735/041.2
• US Class Current: 1/1
• 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. A micromechanical rotation rate sensor, comprising a substrate whose base surface is aligned parallel to a plane comprising an x-axis and a y-axis, 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 configured to 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 plane,

wherein the first and second seismic masses are coupled to one another by at least one first and one second coupling device that comprises at least one essentially rigid coupling beam and at least one torsion spring for allowing rotational deflection about one or two axes and for suppressing further rotational deflections and all translational deflections of the least one essentially rigid coupling beam coupling beam.

2. The rotation rate sensor as claimed in claim 1, wherein, 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.

3. The rotation rate sensor as claimed in claim 2, 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.

4. The rotation rate sensor as claimed in claim 2, wherein the first and second seismic masses of the rotation rate sensor are suspended and coupled by at least the first and second coupling devices and are configured to move exclusively along 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 and all in-phase deflections of the first and second seismic masses are suppressed.

5. The rotation rate sensor as claimed in claim 2, wherein the at least one essentially rigid coupling beam is coupled by spring elements on one side to the first seismic mass and on an other side to the second seismic mass.

6. The rotation rate sensor as claimed in claim 5, wherein the first coupling device is configured to force 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 configured to force antiphase deflections of the seismic masses with respect to the first read mode and with respect to the second read mode, and suppress in-phase deflections with respect thereto, suppressing all in-phase deflections of the first and second seismic masses.

7. The rotation rate sensor as claimed in claim 5, wherein at least one coupling beam of at least one of the coupling devices is associated with two or more read devices which are configured to detect the rotational deflection of this coupling beam with respect to the first or second read mode in phase and in antiphase, one of the read modes being in phase and the other read mode being in antiphase.

8. The rotation rate sensor as claimed in claim 7, wherein the coupling beam is 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 stiff at least with respect to a parasitic rotational deflection about the y axis, wherein the centers of longitudinal sides of the two read devices, 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.

9. The rotation rate sensor as claimed in claim 1, wherein the first and the second seismic masses have essentially the same mass and wherein 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.

10. The rotation rate sensor as claimed in claim 1, wherein the rotation rate sensor comprises a first sensitive axis that lies on the plane, the first sensitive axis is parallel to the x axis or to the y axis, and the second sensitive axis is parallel to z axis, the z axis being at a right angle to the plane.

11. The rotation rate sensor as claimed in claim 1, wherein the at least one drive device is rigidly connected to the first or to the second seismic mass.

12. The rotation rate sensor as claimed in claim 1, 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 translational decoupling is provided in all other directions.

13. The rotation rate sensor as claimed in claim 12, wherein the drive device is in this case additionally suspended on the substrate by at least one further spring element, with this suspension configured to be stiff on the x-y plane and 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.

14. The use of a rotation rate sensor as claimed in claim 1 in motor vehicles, for detection of the yaw rate and for detection of a roll rate or a pitch rate of the vehicle.

15. A micromechanical rotation rate sensor, comprising:

a substrate whose base surface is aligned parallel to a plane comprising an x-axis and a y-axis, 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 configured to 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 plane, and

wherein the deflection of the first and second seismic masses in each of at least two read modes are detected, with the deflection of one of the two seismic masses in each case being detected in opposite phases by two read devices with respect to the antiphase deflection, wherein one seismic mass is in phase and to the other seismic mass is in antiphase, and at least two read devices for detecting a capacitance increase when the other read device detects a capacitance decrease.