Rotational speed sensor having a coupling bar

• US 8,261,614 B2
• Filed: 03/12/2007
• Issued: 09/11/2012
• Est. Priority Date: 03/10/2006
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Hartmann, Bernhard, Günthner, Stefan
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US12/281,699
• Publication Number:
  US 20100037690A1
• Time in Patent Office: 2,010 Days
• Field of Search: 735/041.2, 735/040.4, 735/041.4, 735/041.6
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion
• CPC Class Codes: G01P 15/0888 for indicating angular acceleration
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.

Abstract

A rotational speed sensor including at least one substrate, at least two base elements which each have a frame, a means for suspending the frame from the substrate, at least one seismic mass and one means for suspending the seismic mass from the frame. One or more drive means are provided for driving one or more base elements and one or more reading devices. The at least two base elements are coupled to one another by means of at least one coupling bar.

Claims

1. A rotational speed sensor comprising:

at least one substrate having a base area oriented parallel to an x-y plane of a Cartesian coordinate system,

at least two base elements each having a frame, a means for suspending the frame from the at least one substrate, at least one seismic mass and a means for suspending the seismic mass from the frame,

at least one drive means for driving at least one base element and at least one reading device, wherein the at least one reading device is connected to the at least one substrate for sensing deflections of the seismic masses and/or the frames, and

at least one coupling bar for coupling the at least two base elements, wherein the coupling bar includes two ends, and each end of the coupling bar is coupled to one or more of the seismic masses, either directly or by one or more spring elements, to suppress translatory deflections of the seismic masses in the same direction in at least one reading mode.

2. The rotational speed sensor as claimed in claim 1, wherein the at least one drive means acts on at least one frame, at least one seismic mass, or at least one frame and at least one seismic mass.

3. The rotational speed sensor as claimed in claim 1, wherein the at least one drive means is configured to drive the at least two base elements in a y-direction, and the rotational speed sensor is configured to sense rotational speeds about an x-axis, a z-axis, or both axes.

4. The rotational speed sensor as claimed in claim 1, wherein the coupling bar is suspended from at least one spring element which is clamped to the substrate and forms at least one anchoring point with the substrate, wherein the spring element is clamped or attached so as to limit translatory deflections of the coupling bar.

5. The rotational speed sensor as claimed in claim 4, wherein the coupling bar is suspended from the at least one spring element in the region of a center of gravity of the coupling bar.

6. The rotational speed sensor as claimed in claim 5, wherein the center of gravity of the coupling bar coincides with a center of gravity of the rotational speed sensor.

7. The rotational speed sensor as claimed in claim 6, wherein the center of gravity of the coupling bar coincides with a center of gravity of the rotational speed sensor with respect to the x-y plane.

8. The rotational speed sensor as claimed in claim 4, wherein the at least one spring element is a torsion spring that permits a rotational deflection of the coupling bar about the z-axis, the x-axis, or the z-axis and the x-axis.

9. The rotational speed sensor as claimed in claim 1, wherein the seismic masses are each suspended so as to be deflectable about a torsion axis, wherein the torsion axis extends essentially parallel to a driving direction.

10. The rotational speed sensor as claimed in claim 1, wherein at least two seismic masses have a center of gravity which lie in a z-direction and outside of a plane extending through a respective frame.

11. The rotational speed sensor as claimed in claim 1, wherein each of the seismic masses is assigned a reading device.

13. The rotational speed sensor as claimed in claim 1, said rotational speed sensor being configured to sense a rotational speed about an x-axis,

wherein the base elements are driven in a y-direction,

wherein the frames of the base elements are each suspended from the substrate by spring elements which are elastic in the y-direction and substantially rigid in an x-direction and a z-direction,

the seismic masses of each base element are suspended from a respective frame by spring elements which are configured to (i) permit torsion about a y-axis, (ii) be elastic in the z-direction, or (iii) permit torsion about the y-axis and be elastic in the z-direction,

the coupling bar is suspended from the substrate by a torsion spring which permits torsion about the x-axis and is rigid in the x-direction and the y-direction.

14. The rotational speed sensor as claimed in claim 1, said rotational speed sensor being configured to sense a rotational speed about an x-axis and a z-axis,

wherein the base elements are driven in a y-direction,

wherein the frames of the base elements are each suspended from the substrate by spring elements which are substantially rigid in an x-direction and a z-direction and elastic in the y-direction,

the seismic masses each have a center of gravity that lies in the z-direction and outside of a plane extending through the respective frame,

the seismic masses each being suspended from the respective frame by spring elements which (i) substantially permit torsion about a y-axis, (ii) are elastic in the z-direction, or (iii) substantially permit torsion about the y-axis and are elastic in the z-direction,

the coupling bar is suspended from the substrate by a torsion spring that permits torsion about the x-axis and is rigid in the x-direction and the z-direction, and

at each end of the coupling bar a separate part of the coupling bar is coupled to a central piece of the coupling bar by a torsion spring, said torsion spring being substantially rigid in the x, y and z-directions and permits torsion about the y-axis, wherein the separate parts of the coupling bar are each coupled to the seismic masses of a respective base element by spring elements.

15. The rotational speed sensor as claimed in claim 1, said rotational speed sensor being configured to sense a rotational speed about an x-axis and a z-axis,

wherein the base elements are driven in a y-direction,

wherein the frames of the base elements are each suspended from the substrate by spring elements that are substantially rigid in a z-direction and elastic in a y-direction and x-direction,

the seismic masses of each base element are suspended from the respective frame by spring elements that (i) substantially permit torsion about a y-axis, (ii) are elastic in the z-direction, or (iii) substantially permit torsion about the y-axis and are elastic in the z-direction, and

the coupling bar is suspended from the substrate by a torsion spring that permits torsion about the x-axis and the z-axis and is substantially rigid in the x-direction and the z-direction.

16. The rotational speed sensor as claimed in claim 1, wherein said rotational speed sensor is a micro-electric mechanical system (MEMS) or MEMS module.

17. The rotational speed sensor as claimed in claim 16, wherein the MEMS or MEMS module has mechanical and electronic means for (i) connecting to further MEMS modules, (ii) interacting with further MEMS modules, (iii) interacting with at least one electronic signal processing circuit, or (iv) any combination thereof.

18. A method for manufacturing the rotational speed sensor of claim 16, comprising the step of forming micromechanical elements of the rotational speed sensor by means of a manufacturing process for manufacturing micromechanical systems from a substrate.

19. The method of claim 18 comprising the step of forming micromechanical elements of the rotational speed sensor by means of a manufacturing process for manufacturing micromechanical systems from a substrate composed of crystalline silicon, a plurality of layers of semiconductor material, metal, metals, or any combination thereof.

20. The method of claim 18 further comprising the step of forming the rotational speed sensor at least in parts.

12. The rotational speed sensor as claimed in 1, wherein a sensed rotational speed can be determined from a difference signal of the at least one reading device and another reading device which are each assigned to respective seismic masses of a base element, and from the difference signal of the reading devices that are assigned to different base elements.