JP2001330525A - Torque amount converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque amount converter capable of performing torque measurement with high sensitivity and with high accuracy while maintaining high torsional rigidity necessary for torque measurement. SOLUTION: A deformable part 5 is formed in the direction of a center axis L between a drive-side flange part 2 and a driven-side flange part 3 by a means such as cutting. An outer circumferential surface 8 of the deformable part 5 is formed into a circular arc shape (a round groove shape) around the center axis L. The wall thickness of the deformable part 5 is minimized at the middle part of the round groove. This can increase stresses concentrating in the thinnest wall part of the round groove. The thickness of the thinnest wall part of the round groove, acting as a distortion sensing part, can be therefore increased in comparison with a conventional shape having a flat part when the same amount of distortion is measured. Accordingly, the angle of distortion and the deflection of a shaft by bending can be decreased, the amount of torque can be measured with high sensitivity and with high accuracy, and high torsional rigidity with high responsiveness to a steep change in torque amount can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque transducer for measuring torque, and particularly to measuring a torque of a wheel rotating at a high speed while maintaining a high torsional rigidity required for the measurement. The present invention also relates to a torque converter that can measure torque with high sensitivity and high accuracy.

[0002]

2. Description of the Related Art As a measuring instrument for measuring a torque generated on a wheel or the like of an automobile rotating at a high speed, a driving force transmission system between a driving roller rotated by a wheel and a dynamometer or a brake device is generally used. One having a structure in which a cylindrical strain body is connected between a driving side coupling portion and a driven side coupling portion is used. A strain gauge is attached to the outer peripheral surface or inner peripheral surface of the cylindrical flexure element, and the strain is proportional to the torque generated when the rotational force is transmitted from the drive coupling section to the driven coupling section. The body's shear strain is measured electrically. In order to accurately measure the amount of strain using this strain body, it was necessary to reduce the outer diameter of the strain body or to reduce the thickness of the strain body to generate large strain. However, contrary to these required conditions, when measuring the amount of torque generated at the wheels of the vehicle, a sudden change in torque occurs in the power transmission system when the vehicle suddenly starts or stops. To measure sudden torque changes,
The flexure element must have high responsiveness, and therefore high torsional rigidity is required.Contrary to the conditions for realizing high sensitivity and high precision, increase the outer diameter of the flexure element or increase the strain. It was necessary to increase the body thickness. As described above, the conditions for measuring the strain amount with high sensitivity and high accuracy by using the strain body,
The conditions for increasing the responsiveness are contrary to each other, and it has not been easy to realize a measuring instrument satisfying all the conditions.

In order to solve such a problem,
JP-A-6-229853 and JP-A-7-229
Japanese Patent Application Publication No. 802 discloses a structure of a torque converter as described below. A thin cylindrical portion is provided in a predetermined narrow region in the rotation direction of the cylindrical strain body. By increasing the outer diameter of the thin-walled cylindrical portion as much as possible, when measuring the amount of torque generated in the wheels or the like of an automobile, it is possible to cope with a sudden change in torque at the time of sudden start or sudden stop.
It is possible to provide a transducer having high torsional rigidity.
Then, a predetermined portion of the outer peripheral surface of the thin-walled cylindrical portion is subjected to a sliding process in a planar shape to provide a thinner portion than the other thin-walled cylindrical portions, and a large strain is generated in the planar strain-generating portion. This enables highly accurate measurement. That is,
In a strain-generating body provided in a thin-walled cylindrical portion with a planar strain-generating portion having a thickness smaller than the thickness of other portions of the thin-walled cylindrical portion,
By arbitrarily setting the width, thickness, etc. of the width, outer diameter, and wall thickness of the thin cylindrical portion,
High sensitivity and high precision measurement can be performed while securing high torsional rigidity.

[0004]

In the torque transducer described in the above-mentioned publication, the flat strain-forming portion formed at a predetermined position of the thin cylindrical portion has a constant width as a flat thin portion. And is formed parallel to the central axis. However, this structure is liable to cause torsion and bending of the shaft, and is disadvantageous for measuring the torque amount with high accuracy. In this case, a method has been considered in which round ends are formed at both ends of the flat thin portion to prevent the influence of stress concentration. However, this is not a sufficient countermeasure method, and the thickness of the flat portion is increased for this countermeasure. However, there is a problem that it is necessary to enlarge the outer shape of the flexure element. Further, the cylindrical strain body disposed between the driving side coupling portion and the driven side coupling portion is formed separately. It is difficult to align the shaft,
There is a disadvantage that it takes time to assemble.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and realizes high responsiveness by having high torsional rigidity, and can measure a torque amount with high sensitivity and high accuracy. It is intended to provide a torque converter.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a driving side flange, a driven side flange, and a substantially cylindrical strain generating portion formed therebetween are provided. It is integrally formed, has an opening at the center thereof, and forms a groove having an arc-shaped cross section toward the central axis in the circumferential direction of the outer peripheral surface of the strain generating portion, and a part of a side surface of the opening. Wherein strain gauges are attached at equal intervals on the inner peripheral surface of the strain-generating portion, around the thinnest portion of the strain-generating portion. By making the shape of the thin portion formed in the strain generating portion an arc-shaped groove shape, it is possible to reduce the torsion angle generated in the thin portion and bending due to bending of the shaft,
High torsional rigidity for maintaining high responsiveness can be obtained.

According to a second aspect of the present invention, in the first aspect, the opening is formed from the drive side flange side to the driven side flange side. The bottom portion is formed in the driven-side flange, and a circuit board for mounting an electronic circuit is mounted in the opening.

According to a third aspect of the present invention, in order to solve the above-mentioned problem, a lid is attached to the opening in the first or second aspect. It is.

According to a fourth aspect of the present invention, there is provided the invention as set forth in any one of the first to third aspects, further comprising a transformer mounted on an outer portion of a diameter of the driven flange. It is characterized by having.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a torque converter according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan view showing an embodiment of a strain generating element of the torque converter according to the present invention, and FIG. 2 is a side view of FIG. 1 and a partial sectional view taken along line EE. As shown in the figure, the strain generating element 1 has a substantially cylindrical shape formed between the driving side flange 2, the driven side flange 3, and the driving side flange 2 and the driven side flange 3. It is roughly composed of a distortion portion 5.

An outer end surface (left side in the figure) of the drive side flange portion 2 is provided, for example, in a power transmission system intermediate between a measurement roller of a chassis dynamo rotated by wheels of an automobile and loads of a dynamometer, a brake mechanism, and the like. The drive-side connecting member (not shown) connected to the drive shaft 6 is connected using the screw hole 6. A plurality of screw holes 6 penetrate the drive side flange portion 2 and are provided at substantially equal concentric circles at equal intervals. In the driven side flange 3, a plurality of load members (not shown) of the driving force transmission system are provided at a plurality of screw holes 7, which pass through the driven side flange 3 and are provided at substantially regular intervals on a concentric circle.
Combined using In addition, the driving side flange portion 2, the driven side flange portion 3, and the strain generating portion 5 formed between them rotate when measuring the torque amount, so that they are necessary for the circuit for measuring the torque amount of the strain generating portion. Various methods have been adopted to transmit and receive a high power transmission and a signal corresponding to the measured torque amount from outside, that is, from a fixed side that does not rotate during measurement. FIG. 3 is a diagram illustrating an example in which power and signals are transmitted using a transformer between the driven side flange portion 3 that is the rotating side and the fixed side 20 disposed on the outer peripheral portion thereof. In this example, the secondary-side magnetic core portion 14 of an annular transformer that receives power from the fixed side 20 and transmits a signal corresponding to the amount of torque to the fixed side 20 is installed on the driven side flange portion 3, The fixed side 20 has a structure in which a primary magnetic core 24 of a transformer coupled thereto is installed in the form of a rotary transformer. That is, the fixed side 20 is connected to the driven side flange portion 3.
A primary magnetic core portion 24 of the transformer coupled to the secondary magnetic core portion 14 of the transformer provided on the outer peripheral portion of the transformer through a minute gap g. It is covered and fixed to a fixing base 21 with screws 23.

The strain generating portion 5 is a portion formed between the driving side flange portion 2 and the driven side flange portion 3 by means of cutting, grinding or the like toward the center axis L direction of the strain generating body 1. It is. The tip of the processed portion formed by this cutting, grinding, or the like, that is, the outer peripheral surface 8 of the strain-generating portion 5 is formed in an arc shape (R-groove shape) toward the central axis L, and the R-groove is formed. The central portion is formed such that the thickness of the strain generating portion 5 is minimized. Thus, by forming the R groove shape,
The thickness between the driving side flange portion 2 and the thinnest portion formed by the R groove, and the thickness between the driven side flange portion 3 and the thinnest portion formed by the R groove gradually change. Stress can be prevented from concentrating on the boundary region between the groove and the strain-generating portion 5, and the stress concentrated on the thinnest portion of the R groove can be increased. In comparison, when detecting the same amount of strain, the thickness of the thinnest portion of the R groove serving as the strain sensing portion can be increased. Therefore, it is possible to reduce the torsion angle and the bending caused by the bending of the shaft caused by thinning the wall thickness, and it is possible to measure the amount of torque with high accuracy, and to cope with a sudden change in the amount of torque. High torsional rigidity for high response can be obtained.

The thickness of the strain sensing portion becomes thicker as the distance from the thinnest portion, which is the center of the R groove, becomes lower due to the R groove shape, and the strain detection sensitivity decreases. Since the stress concentrated on the thinnest portion can be increased as described above, it is possible to design the thickness of the strain sensing portion in consideration of the decrease in the strain detection sensitivity. The driving-side flange portion 2 and the driven-side flange portion 3 are formed integrally with the strain-generating portion 5 to constitute the strain-generating body 1. The outer diameter and the wall thickness of the drive side flange portion 2 and the driven side flange portion 3 are formed to be larger than those of the strain generating portion 5 cut toward the center axis L. As a result, high torsional stiffness having high responsiveness to the measurement of a sudden change in torque can be obtained.

An opening 10 is formed at the center of the strain body 1 about the center axis L. The opening 10 is formed from the drive side flange portion 2 side to the driven side flange 3 side through the strain generating portion 5, and the bottom portion 12 reaches the inside of the driven side flange 3. The opening 10 has a lid 1.
1 is provided, and at normal times (when measuring the amount of torque),
It is in a closed cold state covered with. In the opening 10, a plurality of strain gauges (described later) attached to the side surface, an electronic circuit for processing the output of a Wheatstone bridge circuit composed of the strain gauges, and electric power transmitted from the outside as a power supply for the electronic circuit. A circuit board 13 on which a circuit to be converted is mounted is provided. By providing the lid 11 and closing the opening 10, the wind, centrifugal force, and the like generated due to high-speed rotation during measurement prevent problems such as peeling of the attached strain gauge and disconnection of the circuit wiring.

FIG. 4 is a plan view of the strain generating section 5. Eight strain gauges (A1 to A4, B1 to B4) are attached at predetermined intervals on the inner peripheral surface of the opening 10 formed through the strain generating portion 5. A dotted line 15 shown in the figure indicates the thinnest portion of the R groove formed on the outer peripheral surface of the strain generating portion 5, and the strain gauges (A1 to A4, B1 to B4) attached to the opening 10 are:
It is attached on the inner peripheral surface corresponding to the thinnest portion of the R groove. Each of the strain gauges is coated with butyl rubber, subjected to a moisture proof treatment, and then subjected to a potting treatment with silicon.

Further, strain gauges (A1 to A4, B1 to B4)
Are connected as shown in FIG. 5 to form a Wheatstone bridge circuit 16. The attached strain gauge is distinguished into a strain gauge that becomes a compressive strain and a strain gauge that becomes a tensile strain by a shearing force proportional to the amount of torque generated in the strain element 1, and a change in resistance of both strain gauges is output 17. Are formed in the connected electronic circuit (circuit board 13).

[0018]

As described above, according to the torque converter according to the present invention, the strain-generating portion is subjected to cutting or the like into an R-groove shape so that stress is concentrated on the thinnest portion of the strain-generating portion. As compared with the conventional flat-shaped strain-generating portion, the thickness of the thinnest portion required to detect the same amount of strain can be increased, that is, the strain sensing portion can be made thicker. A high torsional rigidity having a high response to a sudden change in the amount of torque can be obtained. Further, since the torsion angle and the bending due to the bending of the shaft can be reduced, the torque amount can be measured with high accuracy.

Further, since the driving side flange portion, the driven side flange portion, and the strain generating portion are integrally formed, the outer diameter and the thickness of the driving side flange portion and the driven side flange portion can be increased. A high torsional stiffness can be obtained, and ideal deformation of the strain sensing unit at the time of measuring the amount of torque can be realized, so that high-sensitivity and high-accuracy torque measurement can be performed.

Furthermore, since the lid is provided at the opening, it is possible to prevent the attached strain gauge from being separated or disconnected due to wind force, centrifugal force or the like due to high-speed rotation during measurement.
It is possible to prevent the circuit board and the like provided in the opening from being deteriorated due to the influence of moisture or dust from the outside.

[Brief description of the drawings]

FIG. 1 is a plan view showing one form of a flexure element of a torque converter according to the present invention.

FIG. 2 is a side view of FIG. 1 and a partial cross-sectional view taken along line EE.

FIG. 3A is a plan view showing one embodiment of a torque converter according to the present invention. (B) It is the side view of figure (a), and the fragmentary sectional view in the FF line.

FIG. 4 is a plan view showing one embodiment of a strain generating portion according to the present invention.

FIG. 5 is a diagram showing a Wheatstone bridge circuit constituted by a strain gauge.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 strain generating body 2 drive side flange portion 3 driven side flange portion 5 strain generating portion 6, 7 screw hole 8 outer peripheral surface 10 opening 11 lid 12 bottom 13 circuit board 14 secondary magnetic core portion 24 primary magnetic core portion

Claims (4)

[Claims] 1. A drive side flange, a driven side flange,
A substantially cylindrical strain-generating portion formed between them is integrally formed, and an opening is provided at the center thereof. In the circumferential direction of the outer peripheral surface of the strain-generating portion, a cross section is taken toward the central axis. An arc-shaped groove is formed, and strain gauges are attached at equal intervals on the inner peripheral surface of the strain-generating portion forming a part of the side surface of the opening, around a thinnest portion of the strain-generating portion. A torque converter comprising: 2. The opening is formed from the drive side flange side to the driven side flange side, and the bottom is formed in the driven side flange, and an electronic circuit mounting is formed in the opening. 2. The torque converter according to claim 1, further comprising a circuit board for mounting. 3. The torque converter according to claim 1, wherein a lid is attached to the opening. 4. The torque amount converter according to claim 1, wherein a transformer is mounted on a portion of the driven side flange in a radially outward direction.