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Title:
TORSIOMETER
Document Type and Number:
WIPO Patent Application WO/2020/188512
Kind Code:
A1
Abstract:
A torsiometer (1) for determining torsiometric characteristics of a component (100) of an automotive transmission system, comprising a spindle (6) configured to receive the first member (101) of the component (100), a motor unit (5) connected to the spindle and configured to drive it in rotation, a reaction unit (10) facing the spindle and provided with a restraining element (79) for the second member (102) of the component (100), an encoder (9) configured to measure the rotation angles of the spindle (6) and a torsiometric cell (8) configured to measure the torque transmitted to the component, wherein the torsiometric cell (8) is interposed between the motor unit (5) and the spindle (6), coaxially with the latter, and is connected to the motor unit (5) through a multi-stage universal joint (28) that absorbs the bending loads.

Inventors:
CASTRO DAMIANO (IT)
Application Number:
PCT/IB2020/052516
Publication Date:
September 24, 2020
Filing Date:
March 19, 2020
Export Citation:
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Assignee:
DAYCO EUROPE SRL (IT)
International Classes:
G01L3/04; F16F15/00; F16F15/10; G01M13/025; G01M15/04
Foreign References:
US20110011169A12011-01-20
CN108152030A2018-06-12
Attorney, Agent or Firm:
FRANZOLIN, Luigi et al. (IT)
Download PDF:
Claims:
CLAIMS

1. A torsiometer, particularly for determining a torsiometric characteristic of a component (100) of an automotive transmission system, said component (100) comprising at least a first member (101) and a second member (102) rotationally coupled together by at least one elastic member (103) interposed therebetween, the torsiometer (1) comprising:

a spindle (6) having a rotation axis (A) and configured to receive the first member (101) of said component (100);

a motor unit (5) connected to the spindle (6) and designed to drive said spindle (6) to rotate about said axis (A);

a reaction unit (10) facing the spindle (6) and provided with a restraining element (79) for the second member (102) of said component (100);

an encoder (9) configured to measure the rotation angles of the spindle ( 6 ) ; and

a torsiometric cell (8) configured to measure the torque transmitted to the component (100);

characterized in that the torsiometric cell (8) is interposed between the motor unit (5) and the spindle (6), coaxially with the latter, and is connected to at least one of the spindle (6) and the motor unit (5) through a joint (28) configured to absorb the bending loads .

2. The torsiometer as claimed in claim 1, characterized in that said joint (28) is a multi-stage universal joint.

3. The torsiometer as claimed in claim 2, characterized in that said universal joint (28) comprises a plurality of elements (29, 30, 31, 32, 33) constrained to each other in a rotatable manner about mutually orthogonal axes (B, C, D, E) .

4. The torsiometer as claimed in claim 2 or 3, characterized in that said universal joint (28) defines four axes (B, C, D, E) of relative rotation between said elements (29, 30, 31, 32, 33), said axes being mutually orthogonal pair-wise axes.

5. The torsiometer as claimed in claim 3 or 4, characterized in that at least three of said elements (29, 30, 31) are annular and are telescopically mounted one inside the other.

6. The torsiometer as claimed in any one of the preceding claims, characterized in that said joint (28) is arranged between an output member (7) of the motor unit (5) and said torsiometric cell (8) .

7. The torsiometer as claimed in claim 6, characterized in that the torsiometric cell (8) is arranged between an output member (32) of the universal joint (28) and a flange (50) of said spindle ( 6 ) .

8. The torsiometer as claimed in one of the preceding claims, characterized in that the output member of the motor unit (5) comprises a tubular sleeve (7) and the spindle (6) comprises at least one portion (56) supported coaxially inside the tubular sleeve ( 7 ) .

9. The torsiometer as claimed in claim 8, characterized in that the spindle (6) is supported axially with respect to the sleeve (7) through a constraint system (72) configured so as to filter every force and torque exchanged between the spindle (6) and the sleeve (7) except for an axial constraint reaction.

10. The torsiometer as claimed in claim 9, characterized in that said constraint system comprises at least one punctiform axial support .

11. The torsiometer as claimed in claim 10, characterized in that the punctiform axial support is formed between at least one axial pin (67) rigidly connected to the spindle (6) and at least one bar mounted in a diametric direction through the spindle (6), said bar being constrained to the sleeve (7) at its ends.

12. The torsiometer as claimed in claim 11, characterized in that the axial constraint system comprises two bars (64) and two pins (67) defining opposite punctiform axial supports, each bar (54) being constrained to the sleeve (7) by means of adjustable end axial supports (68) opposite to the respective pin (67), each bar (64) being furthermore constrained to the sleeve (7) in a radial and transverse direction.

13. The torsiometer as claimed in one of claims 8 to 12, characterized in that the motor unit (5) comprises an electric motor (14) and a reduction gear (15) actuating a hollow shaft (18) rigidly connected to the sleeve (7), said encoder (9) having a casing (70) fixed to a casing of the reduction gear (15) and a mobile unit connected to the spindle (6) through a shaft (57) internally coaxial to said hollow shaft (18) .

14. The torsiometer as claimed in any of the preceding claims, characterized in that said reaction unit (10) comprises a reaction element (79) configured to block the second member (102) of the component and at least one slide (75, 78) for adjusting the position of the reaction element (79) with respect to the spindle (6) .

Description:
"TORS IOMETER"

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no. 102019000004079 filed on 20/03/2019, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a torsiometer, and particularly to a torsiometer for torsional measurements on components of automotive transmission systems such as, for example, tensioners for belt transmission systems.

For greater clarity, reference shall be made hereinafter to this application by way of non-limitative example.

BACKGROUND ART

As is known, tensioners for belt transmission systems basically comprise a base designed to be fastened to the engine, an arm rotatable on a pin carried by the base and a pulley carried by the arm at one end thereof and designed to cooperate with the belt to transmit a tensioning force thereto.

For this purpose, the tensioner comprises a spring having an end constrained to the base and an end constrained to the arm, so as to transmit a tensioning torque to the arm.

In order to check the performance of the tensioners, a torsiometer is normally used in which rotation angles of the arm are set with respect to the base and the tensioning torque is measured .

Known torsiometers normally comprise a motor unit constituted by an electric motor equipped with a spindle on which the base of the tensioner is mounted and a torsiometric unit comprising a torsiometric cell facing the spindle and coaxial thereto. The torsiometric cell is interposed between a fixed support, the position of which relative to the spindle is adjustable by a slide, and a reaction member on which the arm discharges its force in response to the rotation of the base. The angle of rotation of the base is measured by an encoder associated with the spindle.

Torsiometers of the previously described type suffer from a certain number of causes of error.

A first cause of error is linked to the fact that transducers of the torsiometric cell, no matter how opportunely oriented, also "sense" a flexural component of the deformation, in addition to the torsional one. The resulting error is proportional to the torque.

A second cause of error is linked to the fact that the tensioner generates radial forces that tend to misalign the spindle and the torsiometric cell; the shift grows with wear and causes systematic errors, the influence of which increases as the length of the tensioner's arm decreases.

Another cause of error is the flexure of the spindle, proportional to the torque.

Finally, another cause of error is constituted by the fact that the encoder detects angles not exactly corresponding to the actual rotation, as part of the stress that should cause pure torsional deformation of the spring, in reality produces flexural deformations.

From the combined foregoing considerations, the need emerges for producing a torsiometer that reduces measurement uncertainty. DISCLOSURE OF INVENTION

The aforementioned object is achieved by a torsiometer according to claim 1, wherein the torsiometric cell is interposed between the motor unit and the spindle, coaxially with the latter, and is connected to at least one of the spindle and the motor unit by a joint configured to absorb bending loads.

In this way, the above described causes of error are eliminated.

According to a preferred embodiment of the invention, the joint is a multi-stage universal joint. Preferably, this joint comprises a plurality of elements telescopically mounted one inside the other and constrained to each other in a rotatable manner about mutually orthogonal pair-wise axes.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, a preferred embodiment is described hereinafter, by way of non-limitative example and with reference to the accompanying drawings, in which :

Figure 1 is a perspective view of a torsiometer according to the invention;

Figure 2 is a section of the torsiometer of Figure 1 along an axial centre plane;

Figure 3 is an enlarged view of a detail of Figure 2;

Figure 4 is a section along the line IV- IV of Figure 3;

Figure 5 is a perspective view of a joint of the torsiometer of Figure 1; and

Figure 6 is an exploded perspective view of the joint of Figure

5.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figures 1 and 2, reference numeral 1 indicates, as a whole, a torsiometer for testing tensioners for belt transmission systems.

The torsiometer 1 essentially comprises:

- a fixed support structure 2, comprising a horizontal table 3 and a vertical wall 4;

- a motor unit 5 supported by the vertical wall 4;

- a spindle 6 rotationally coupled to an output member 7 of the motor unit 5 by a torsiometric cell 8 and extending in a cantilever fashion above the table 3;

- an encoder 9 associated with the spindle 6 and designed to measure the rotation angles thereof; and

- a reaction unit 10 mounted on the table 3 in an adjustable position and facing the spindle 6.

More specifically, the motor unit 5 comprises an electric motor 14 and a reduction gear 15, not described in detail as it does not form part of the present invention. The reduction gear 15 comprises an outer casing 16 fixed to the vertical wall 4 in a cantilever fashion on the opposite side of the table 3, and a hollow shaft 18 lying on axis A, extending through an opening 19 in the vertical wall 4 and terminating with a flange 20 (Figure 2) . The hollow shaft 18 receives the motion from an output member of the reduction gear 15, not shown, through a tongue 21 (Figures 3 and 4) .

A sleeve lying on axis A, constituting the output member 7 of the motor unit 5 and therefore referred to hereinafter as "sleeve Ί " for brevity, is fixed to the flange 20.

The sleeve 7 extends over the table 3 and is supported, in proximity of its opposite end 25, by an adjustable support 26 fixed to the table 3 by a radial bearing 27.

The end 25 of the sleeve 7 is connected to the load cell 8 by a multi-stage universal joint 28, shown in detail in Figures 5 and 6.

With reference to these figures, the universal joint 28 basically comprises three rings 29, 30, 31 and an output flange 32, telescopically mounted one inside the other.

The outer ring 29 is constrained to the sleeve 7 with rotational freedom about an axis B orthogonal to the axis A and incident therewith. This constraint is implemented by means of a pair of diametrically opposite brackets 33, radially fixed in an outwardly cantilever fashion on the end 25 of the sleeve 7, and a pair of radial pins 34 lying on axis B, engaging respective holes 35 of the brackets 33 in an angularly free manner and embedded in respective diametrically opposite radial holes 36 of the outer ring 29 (Figures 3 and 6) .

The intermediate ring 30 is constrained to the outer ring 29 with rotational freedom about an axis C orthogonal to the axis B. This constraint is implemented by means of a pair of radial pins 37 lying on axis C, engaging respective holes 38 of the outer ring 29 in an angularly free manner and embedded in respective diametrically opposite radial holes 39 of the intermediate ring 30.

In an entirely similar manner, the inner ring 31 is constrained to the intermediate ring 30 with rotational freedom about an axis D perpendicular to the axis C. This constraint is implemented by means of a pair of radial pins 42 lying on axis D, engaging respective holes 43 of the intermediate ring 30 in an angularly free manner and embedded in respective diametrically opposite radial holes 44 of the inner ring 31.

Finally, the output flange 32, this also having an annular shape, is constrained to the inner ring 31 with rotational freedom about an axis E perpendicular to the axis D. This constraint is implemented by means of a pair of radial pins 45 lying on axis E, engaging respective holes 46 of the inner ring 31 in an angularly free manner and embedded in respective diametrically opposite radial holes 47 of the output flange 7.

The flange 32 is connected to the spindle 6 by the torsiometric cell 8.

More specifically, the spindle 6 comprises a shaft 48 lying on axis A, which is radially supported by a bearing 49 housed in the end 25 of the sleeve 7 and extends passing through the universal joint 28, and an end flange 50 facing the flange 32 of the joint. The torsiometric cell 8, having an annular shape, is housed coaxially with the shaft 48 between the flange 32 and the flange 50 of the spindle 6, and has respective end flanges 51, 52, which are respectively fixed to the flange 32 and the flange 50 of the spindle 6 by respective pluralities of axial screws. In Figures 3 and 4, only the screws 53 for connection to the output flange 7 are shown.

The spindle 6 is integrally connected to an elongated shaft 57 housed inside the hollow shaft 18. For this purpose, the spindle 6 comprises a spacer 56 lying on axis A, arranged inside the sleeve 7 and connected to the shaft 48 and to the shaft 57 by respective threaded connections 58, 59. The spacer 56 is radially supported with respect to the sleeve 7 by a bearing 60 at its end 61 opposite to the shaft 48, into which the shaft 57 screws. It is important to note that the bearings 49, 60 support the spindle 6 radially, but in an axially free manner, so as to avoid undesired exchanges of forces.

The axial positioning of the spindle 6 is defined by a constraint system 72 configured so as to avoid the transmission of forces or torque between the spindle 6 and the sleeve 7 (except for the axial constraint reaction) .

This constraint system 72 preferably comprises a punctiform axial support produced as described below.

The sleeve 7 (Figure 4) is equipped with a pair of diametric through slots 62, parallel to each other, which have an elongated section in the axial direction and are aligned with each other in this direction.

In turn, the spacer 56 is provided with a pair of corresponding diametric through slots 63, parallel to each other, which have an elongated section in the axial direction and are aligned with each other in this direction.

The slots 62 and 63 house respective elongated bars 64 with axial clearance. The bars 64 are housed with transversal clearance in the slots 63 of the spacer 56, and instead housed in a sliding manner, but without transversal clearance, in the slots 62.

The bars 64 are provided with respective slots 65, elongated in the axial direction, which are engaged in a sliding manner by respective pins 66 carried by the sleeve 7, so as to create a purely radial (longitudinal) constraint for the bars 64.

The bars 64 rest centrally, with their axial ends facing each other, on axial pins 67 lying on axis A and carried by the spacer

5.

The punctiform axial support ensures that no torque is exchanged between the sleeve 7 and the spindle 6, except for the axial constraint reaction.

The bars 64 are also axially constrained to the sleeve 7 by respective pairs of grub screws 68 housed in respective axial holes 69 of the sleeve 7 and acting axially on the opposite ends of the bars 64, on the side opposite to pins 67. The shaft 57 is connected, in a known manner that is not shown, to the mobile unit of the encoder 9, the casing 70 of which is fixed to the outer casing 16 of the reduction gear 15 by a bracket 71.

The reaction unit 10 (Figures 1 and 2) basically comprises a first slide 75 sliding in a direction parallel to the axis A on guides 76 arranged on the table 3. The first slide 75 carries a vertical support 77 for a second slide 78, sliding with respect thereto in a horizontal direction perpendicular to the axis A. The second slide 78 carries a reaction pin 79 extending in a cantilever fashion in a direction parallel to the axis A (Figures 1 and 4 ) .

The torsiometric cell 9, the encoder 10 and the electric motor 14 are connected to an electronic control unit, which is designed to control the electric motor to perform the measurement cycles and record torque data as a function of the angle of rotation, in a manner which is in itself known.

The operation of the torsiometer 1 is as follows.

Figure 4 schematically shows a tensioner 100 for which it is wished to determine the torsiometric characteristic.

The tensioner 100 comprises, in a known manner, a base 101, an arm 102 rotatable on the base 101 against the action of a spring 103 interposed between them in a known manner, and an idler pulley 104 mounted on an end of the arm 102.

The base 101 of the tensioner is fixed on the flange 50 of the spindle 6 so that the axis of rotation of the arm 102 with respect to the base 101 coincides with the axis A.

The slides 75, 78 of the reaction unit 10 are configured and locked so as to arrange the reaction pin 79 in a position for interacting with the arm 102 of the tensioner 100 mounted on the spindle 6.

The measurement cycle comprises a first step of approach in which the electric motor 14, via the reduction gear 15, the hollow shaft 18, the sleeve 7, the universal joint and the torsiometric cell 8, makes the spindle 6 and the tensioner 100 rotate about the axis A, until the arm 102 comes into contact with the reaction pin 79 (Figure 4) .

From this moment, a further rotation of the spindle 6 produces a deformation of the spring of the tensioner 100, as the arm 102 is locked by contact with the reaction pin 79, and the torsiometric cell 8 reads the torque transmitted in a manner in itself known; the angle of rotation of the spindle 6 is transmitted through the spacer 56 and shaft 57 to the encoder 9 and measured by the latter.

Since the torsiometric cell 8 is connected directly to the spindle 6 and is integral therewith, all error components related to parasitic eccentricities that might occur in known torsiometers , in which, as has been said, the torsiometric cell is usually arranged in the reaction unit, are eliminated.

Furthermore, due to the multi-stage universal joint 28, subjecting the torsiometric cell 8 to flexural stresses is avoided, therefore ensuring that the cell reads the pure torsion torque .

Finally, the punctiform axial support between the sleeve 7 and the spindle 6 ensures that, even in the presence of parasitic load components, albeit avoided due to the configuration of the constraints, there can be no torque transmitted between the sleeve 7 and the spindle 6.

Finally, it is clear that modifications and variants can be made to the described torsiometer 1 without departing from the scope defined in the claims.

For example, the joint 28 could be interposed between the load cell and the spindle 6, instead of between the sleeve 7 and the load cell 8.

Furthermore, the joint 28 and the constraint system 72 could be made in a different manner, as long as they are functionally equivalent.

The torsiometer 1 could be used for determining the torsional characteristic of different components, for example torsion dampers, by opportunely configuring the spindle 6 and the reaction member 79.