Dynamometer, particularly for determining the seating weight in a motor vehicle

• US 7,069,796 B2
• Filed: 10/06/2003
• Issued: 07/04/2006
• Est. Priority Date: 11/11/2002
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Dukart, Anton
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US10/499,049
• Publication Number:
  US 20050103128A1
• Time in Patent Office: 1,002 Days
• Field of Search: 737/79, 738/626.9
• US Class Current: 73/862.69
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01G 7/02 by electromagnetic action

Abstract

A dynamometer (10; 10a; 10b) has a pickup element (11; 11a; 11b), in which a permanent magnet (32) and a sensor (35) are disposed. At least the permanent magnet (32) is surrounded by ferromagnetic material, and the spacing of the permanent magnet (32) from the ferromagnetic material changes upon imposition of a force (F) upon the pickup element (11; 11a; 11b). This change in the spacing causes a change in the field intensity of the permanent magnet (32), which is detected by means of the sensor (35) and converted into a corresponding signal.

Claims

1. A dynamometer (10;

10a;

10b), in particular for determining the weight on a seat in a motor vehicle, having a pickup element (11;

11a;

11b), which has two bearing points (16, 17) spaced apart from one another, having a recess (27;

27a;

27b) in the pickup element (11;

11a;

11b) in the region between the two bearing points (16, 17), having a rodlike element (37;

50) not subjected to bending forces, whose free end, when a load is exerted on the pickup element (11;

11a;

11b), is deflected by a force (F) to be measured, and having a measurement array (33) for detecting the deflection of the free end of the rodlike element (37;

50), wherein the measurement array (33) includes a magnet (32) and a magnetic-field-sensitive sensor (35), wherein the magnet (32) and the magnetic-field-sensitive sensor (35) are disposed stationary relative to one another, and wherein the magnet (32) is spaced closely apart from ferromagnetic material, characterized in that the magnet (32) is disposed inside an elongated recess (30;

30a;

30b) of the ferromagnetic material; and

that the longitudinal axis of the recess (30;

30a;

30b) extends transversely to the direction of the force (f) to be measured and to the length of the rodlike element (37;

50).

2. The dynamometer of claim 1, characterized in that the elongated recess is embodied as a slot (30;

30a;

30b).

3. The dynamometer of claim 1, characterized in that the recess (30b) is embodied in an extension (50) which protrudes into the recess (27b).

4. The dynamometer of claim 1, characterized in that the recess (30a;

30b) begins at the bottom of the first element (27;

27a) in the pickup element (11;

11a).

5. The dynamometer of claim 1, characterized in that the pickup element (11;

11a;

11b) is embodied as a double bending bar, with two rodlike bars (41, 42) disposed parallel to one another; and

that the rodlike element (37;

50) is disposed in the longitudinal axis (12) of the pickup element (11;

11a;

11b).

6. The dynamometer of claim 1, characterized in that the pickup element (11;

11a;

11b) is surrounded by a cup-shaped bearing element (23;

23a), which is coupled with the rocker (20;

20a) of a seat;

that the force (F) to be measured is introduced via the bearing element (23;

23a); and

that the pickup element (11;

11a;

11b) is connected on the one hand to a seat rail (19), as the first bearing point, and to the bearing element (23;

23a) on the opposite side, as the second bearing point.

7. The dynamometer of claim 6, characterized in that between the bearing element (23a) and the pickup element (11a) on the side toward the seat rail (19), a gap (49) is embodied which, if a defined allowable force (F) is exceeded, has the effect that the bearing element (23a) is seated on the pickup element (11a) and thus forms an overload stop.

8. The dynamometer of claim 6, characterized in that the bearing element (23;

23a;

23b) has a round, square or oval cross-sectional area.

9. The dynamometer of claim 6, characterized in that the bearing element (23a), on the side toward the seat rail (19), has an inward-protruding bearing collar (47), which engages a shoulder (46) of the pickup element (11a) from behind.

10. The dynamometer of claim 1, characterized in that the pole axis of the magnet (32) extends parallel to the direction of the force (F) to be measured.