JP2837563B2 - On-axis torque measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a rotating shaft (rotating shaft).
Particularly, two multipole magnets fixed to two linear portions separated from each other in the axial direction on a rotating shaft, and a process in which the magnetism of the multipole magnet is sensed and proportional to the torque The present invention relates to a rotating shaft torque measuring device having a fixed pickup for outputting a signal. The invention further relates to an apparatus for measuring the rotation speed of a rotating shaft and the power transmitted via the rotating shaft.

[0002]

2. Description of the Related Art French Patent No. FR-A-2,626,368 discloses that each pickup which outputs "Yes, No" as an output signal reads the angular position of each magnet, and the rising edge of a processing signal obtained from both pickups ( A device for measuring the torsional moment of a shaft by the phase difference of the front) is described.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for controlling a shaft even when the shaft is blocked or when the rotational speed of the shaft fluctuates.
The object is to make it possible to measure the torque on the shaft. It is another object of the present invention to provide an apparatus having a simple and economical structure capable of measuring a small twist angle.

[0004]

According to the torque measuring device provided by the present invention, the pickup means is disposed between the multipole magnets, and the pickup means detects two sine induction magnetic fields generated by the multipole magnet. It is characterized in that it has detection elements, and the centers of the detection elements are displaced in the angular direction by an interval equal to one-fourth of the period of the induced magnetic field. Other features and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings.

[0005]

FIG. 1 shows a shaft part via a deformable elastic connection constituted by a torsion bar 11.
10 is connected to the shaft part 12. The shaft part 10 is the input shaft,
The shaft portion 12 is connected to a driving device (not shown), and is connected to a driven device (not shown). When the mechanical resistance of the driven device is added to the rotational motion of the shaft portions 10 and 12 and the rotational motion applied by the driving device, the torsional rod is coaxially and concentrically arranged with the shaft portions 10 and 11. Communicated via 11. The rotational movement of the shaft part 10 is guided by a roll bearing 13 provided on a support surface supporting a torsion bar 11. Groove sleeve with play in the angular direction between drive shaft 10 and output shaft 12
The torsion bar 11 can be displaced in the angular direction by an angle corresponding to the play of the grooved sleeve 14. When the angle value corresponding to the play of the groove-shaped sleeve 14 is exceeded, the side surfaces of the tip grooves of the shaft portion 10 and the shaft portion 12 come into contact with each other, and they are directly connected and rotate. A ball bearing 20 having an inner ring 21 and an outer ring 22 is fastened and fixed to the output shaft 12. The inner surface 23 of the inner ring 22 of the ball bearing 20 constitutes a support surface for the multipole magnet 40. The multipole magnet 40 is fixed to a linear portion of the shaft portion 12. This fixing is achieved, for example, by simultaneously supporting the support surface 24 of the shaft portion 12 and the inner surface 23 of the inner ring 21 with the shaft portion.
It can be done by bonding to 12. The sleeve 25 slidably mounted on the input shaft 10 so that the position can be adjusted has a contact shoulder 26 that supports the multipolar magnet 41. The multipole magnet 41 is fixed to the support surface 27 formed on the sleeve 25 in which the linear portion of the shaft portion 10 is fitted, and to the contact shoulder 26. This fixation can be performed by simultaneously bonding the multipolar magnet 41 to the support surface 27 and the contact shoulder 26. Part of the spacing between the two multipole magnets 40 and 41 is a sleeve
It depends on the length of the 25 support surfaces 27. That is, the distal end surface 28 of the sleeve 25 is in contact with the distal end surface 29 of the support surface 24 of the driven shaft 12. The fixing of the sleeve 25 on the drive shaft 10 can be performed by the fixing screw 30

The Hall effect or magnetoresistance (magnet
An oresistance) type pickup 31 is mounted on a support plate 32. The support plate 32 supports the electric connection lines and the electric output lines. This support plate 32
Is accommodated in a fixed casing 35 having a hole 37 through which electric wires pass, and between a shoulder 36 of the fixed casing 35 and an annular spacer 38 abutted on the inner surface of the outer ring 22 of the ball bearing 20. It is fitted. That is, the fixed casing 35 includes a pair of multipole magnets 40 and 41, the pickup 31,
The ball bearing 20 is accommodated therein, and the end 39 of the ball bearing 20 is bent inward at the axial end 43 of the ball bearing 20. Further, between the inner ring 22 and the outer ring 21 of the ball bearing 20, a fixed casing 35 and the fixed casing 35
Sealing joints 44 and 45 are respectively provided between the sleeve 25 and the sleeve 25 for closing.

FIG. 2A is an exploded view of a measuring part. The multipole magnets 40 and 41 are formed of a ferromagnetic material such as plast ferrite made of ferromagnetic particles and a plastic binder. These multipole magnets are magnetized by a known multipole magnetizing method so that the surfaces 401 and 411 are the same. The magnetized magnetic surfaces 401 and 411 face each other. The above-mentioned Hall effect or magnetoresistive pickup 31 is arranged between these two magnetic surfaces 401 and 411 so as not to contact each other. As shown in FIG. 2b, the multi-pole magnets 40, 41 emit induction magnetic fields H40, H41 in a direction perpendicular to the magnetic surfaces 401, 411. The induction fields H40, H41, measured at the midpoint between the magnetic surfaces 401 and 411 in a direction perpendicular to the magnetic surfaces, have a profile represented by a function of a periodic sinusoid. The value measured by the Hall effect or the magnetoresistive pickup 31 is a magnetic induction value generated by adding the induction magnetic fields H40 and H41.

FIG. 3 shows that induction magnetic fields H40 and H41 having a phase difference (phase shift) S at a measurement point located at an intermediate point between the multipole magnets 40 and 41 are applied to a parallel line parallel to the magnetic surfaces 401 and 411. (directr
It is a development view represented by a function of a position on ice). The sum induction magnetic field HR at each point of the quasi-line is equal to the algebraic sum of the magnetic fields H40 and H41 of each sinusoidal curve. This added induction magnetic field HR is composed of two magnetic fields H
This is a sine function with the same period P as 40 and H41. Magnetic phase difference S
Is adjusted by rotating the sleeve 25 with respect to the input shaft 10. This initial adjustment value is fixed by the fixing screw 30.

FIG. 4A is a developed view showing two induction magnetic fields H40 and H41 whose phases match each other when the phase difference S is zero. In this case, the added induction magnetic field HR is 2 at all measurement points.
It is twice the value of one of the two magnetic field components. FIG. 4b shows two induced magnetic fields H40, H41 having opposite phases whose phase difference S is equal to one half period of one of the two magnetic fields H40, H41.
In this case, the value of the added induction magnetic field is zero at all the measurement points. When the value of the initial magnetic phase difference is adjusted to zero, a torsional torque is applied between the input shaft portion 10 and the output shaft portion 12, and the magnets 40 and 41 pass through the torsion shaft 11.
Are mutually displaced in the angular direction, this angular displacement appears as a change in the magnetic phase difference S between the induction magnetic fields H40 and H41. In this case, the added induction field HR is smaller than the initial value shown in FIG. 4A, and when the torsion shift is equal to the half cycle phase difference (S = P / 2), the added induction magnetic field HR becomes zero. If the torque is zero, the shaft portions 10 and 12 are elastically returned to their initial position by the torsion shaft 11, and the induced magnetic field HR returns to its initial value.

FIG. 5 shows a change in the added induction magnetic field HR with respect to three numerical values of the torsional torque. The initial value S = 0 is adjusted when no torque is applied. The added induction magnetic field HR when no torque is applied has a peak value of + 2b as shown in FIG. When a moderate torque is applied, the magnets 40 and 41 are driven to rotate relative to each other, and the induction magnetic field H
The phase difference between 40 and H41 appears as a phase difference of 0 <S <P / 2. In this case, the peak value of the added induction magnetic field HR is + 2b.
Smaller (+ a). When torque is applied to the limit of possible measurement, the magnets 40 and 41 rotate relative to each other, and the induced magnetic field H40
And H41 have a phase difference of S = P / 2, and the added induction magnetic field HR
Becomes zero. The above value a is the value of S (0 <S <P / 2)
, All values between + 2b and 0 can be taken. This value S depends only on the torsional moment applied on the torsion bar 11 via the input shaft 10 and the output shaft 12,
The relationship between the applied torque value and the phase difference S is the torsion bar
Determined solely by 11 physical properties and torsional stiffness. The pickup 31 converts a change in the added induction magnetic field HR, which is a function of the torsional moment, into an electric signal. The pickup 31 is composed of substantially the same Hall effect or magnetoresistive sensing elements 301 and 302, and outputs an output voltage proportional to the added induction magnetic field HR across them.

As shown in FIG. 6, the centers C1 and C2 of the sensing elements 301 and 302 are substantially out of phase with respect to the sinusoidal induction magnetic field HR by 1/4 wavelength, that is, the distance d = (2n + 1). ) (Where n is a positive integer or zero).

FIG. 7 shows the change in the signal indicating the torque measured on the rotating shaft. When a constant torque is applied to the torsion bar 11, the input shaft 10, the torsion bar 11, and the output shaft 12 rotate by the angle θ, and each of the sensing elements 3
01 and 302 output voltage signals V301 and V302. The amplitude of these signals for a constant voltage V ₀ is proportional to the value of the additive induction field HR across each element. These signals are of equal amplitude, have the same characteristics, and have a sinusoidal induction field H.
It changes at the same cycle P as R, and the phases are shifted from each other by P / 4. The center of these signals is a value V ₀ corresponding to the voltage developed by one of the sensing elements in the absence of a magnetic field.
Becomes The value of the angle θ corresponds to the value V ₂ values V ₁ and signal V302 of the signal V301, following relationship: V _q = ^{_{[(V 1 -V 0) 2 +}} (V 2 -V 0) 2 The mean square value V _q expressed by ^1/2 is independent of the angle θ at which the input shaft 10, the torsion shaft 11 and the output shaft 12 rotate simultaneously, and is related only to the amplitudes of the signals V301 and V302. It is related only to the value of the torque applied between the peak value of the added induction magnetic field HR and the input shaft 10 and the output shaft 12. This numerical value V _q is
If the value of V ₀ is known, by measuring the voltages V1, V2, can be obtained directly using known electrical process or processing method. This value V _q is displayed in Figure 7 the initial value of V _0.

[0013] Figure 8 shows the relationship between the torsional torque C _t applied to the V _q and torsion shaft 11 in the case of adjusting the initial magnetic phase difference to zero. In this case, the value of V _q varies in inverse proportion to the applied torque. The initial magnetic phase difference is S =
The value of V _q in the case of fixing to P / 2 varies in proportion to the torque applied as shown in FIG.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment in which the present invention is applied to a rotating shaft having elastic connecting means constituted by a torsion bar.

FIG. 2A is a schematic view of a measuring part of the apparatus of the present invention. FIG. 2b is a diagram illustrating the distribution of the induced magnetic field at the pickup means of the present invention.

FIG. 3 is a schematic diagram showing a change in a magnetic field generated by each magnet and an added induction magnetic field.

FIG. 4A is a schematic diagram showing a change in each magnetic field whose phase matches and a change in an induced magnetic field; FIG. 4B is a schematic diagram showing changes in magnetic fields of opposite phases and the addition induction magnetic field.

FIG. 5 is a schematic diagram showing a change in an added induction magnetic field when torsional moments have different values.

FIG. 6 is a schematic diagram showing a pickup unit in an added induction magnetic field.

FIG. 7 is a change curve of an output signal as a function of a deviation of an angle of a shaft.

FIG. 8 is a schematic diagram showing a change in an output signal as a function of a change in torque when the initial magnetic phase difference is adjusted to zero.

FIG. 9 is a schematic diagram showing a change in an output signal as a function of a change in torque when an initial magnetic phase difference is set to S = P / 2.

[Explanation of symbols]

10 Input shaft 11 Elastic connection means 12 Output shaft 20 Ball bearing 25 Angle adjusting means 31 Pickup means 35 Fixed casing 40, 41 Multipole magnet 44, 45 Sealed joint 301, 302 Induction magnetic field detecting element C1, C2 Center of induction magnetic field detecting element

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01L 3/10 WPI / L (QUESTEL)

Claims (4)

(57) [Claims] 1. Two multipole magnets (40, 41) each fixed to two axially separated linear sections on axes (10, 11, 12), and these two multipole magnets (40, 41). Fixed pickup means (31) for sensing the magnetic field of (40, 41) and outputting an output signal proportional to the torsional moment.
In the device for measuring the torsional moment applied to (10, 11, 12), the pickup means (31) is arranged between the multipole magnets (40, 41), and the pickup means (31) is connected to the multipole magnet (40). 40, 4
1) Two detection elements (301,
302), and that the centers (C1, C2) of the respective detection elements (301, 302) are angularly displaced by a distance (d) equal to one-fourth of the period of the induction magnetic field. Characteristic device. 2. Apparatus according to claim 1, wherein one of the multipole magnets (40, 41) is supported by angle adjusting means (25). 3. The pick-up means (31) wherein the shafts (10, 11, 12) are constituted by two shaft portions (10, 12) connected via elastically deformable connecting members (11). 3. The device according to claim 1, wherein the device is supported via a bearing (20) in a fixed casing (35) supporting the device. 4. A fixed casing (35) comprising two multipole magnets (4).
Device according to any of the preceding claims, containing the first, second, third and fourth housings (0, 41), wherein each end of the pick-up means (31) is closed by a sealing joint (44, 45).