JPH0634692Y2 - Cross coil type indicator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention rotates a magnet rotor by a synthetic magnetic field generated by a cross coil, and indicates a predetermined measurement amount by a pointer that rotates in cooperation with the magnet rotor. The present invention relates to a cross coil type indicating instrument.

[Conventional technology]

Generally, as shown in FIG. 7, the driving unit of a cross coil type instrument has a pair of cross coils L ₁ ,
L ₂ , a magnet rotor Mg rotatably arranged in a synthetic magnetic field generated by the cross coil, and the magnet rotor
Pointer A provided at the end of the rotation axis at the center of Mg, scale plate B for indicating the measurement amount from the rotation position of pointer A, and scale plate B
The zero point stopper pin P is provided at the zero point position for restricting the rotation of the pointer A, and the full spring C for urging the pointer A and the magnet rotor Mg toward the stopper pin P.

In the above structure, as shown in FIG. 8, the cross coil L ₁ ,
Magnetic fields Φ ₁ , which are generated when currents i ₁ and i ₂ flow through L ₂ , respectively
Φ ₂ is Φ ₁ = μ ₁ i ₁ n ₁ S ₁ (1) Φ ₂ = μ ₂ i ₂ n ₂ S ₂ (μ _1,2 : permeability of coils L ₁ and L ₂ , n _{1 , 2} : Number of turns, S _1,2 :
Cross-sectional area). On the other hand, since the magnet rotor Mg rotates in the direction of the combined magnetic field of the magnetic fields Φ ₁ and Φ ₂ , if the rotation angle is α, Therefore, if the coils L ₁ and L ₂ are the same, the equation (2) becomes Therefore, the rotation angle α is set by the drive currents i ₁ and i ₂ . Here, if i ₁ and i ₂ are i ₁ = I _0cos θ i ₂ = I _0cos θ (4) and the angle θ is a value corresponding to a predetermined measurement amount, equations (3) and (4) are obtained. Than, Since α = θ, the direction of the synthetic magnetic field generated by the cross coils L ₁ and L ₂ is the angle θ as shown in FIG.
The magnet rotor Mg rotates to the position of the rotation angle θ corresponding to the predetermined measurement amount against the total dance spring C. Therefore, by reading the position of the pointer A, which rotates together with the magnet rotor Mg, with the scale plate B, the measured amount can be recognized. At this time, the indicated value is Zenmai Spring C
The driving current values i ₁ and i ₂ that determine the magnitude of the combined magnetic field so that they do not deviate significantly from the predetermined value due to the biasing force of
It is preset in consideration of the urging force so as to sufficiently overcome the urging force of all dance springs C.

By the way, there has been proposed an indicating instrument using a pulse current having a duty according to a predetermined calculation amount as a drive current applied to the cross coil. FIG. 5 has a conventional configuration of a cross-coil type indicator instrument based on such pulse current. In FIG. 5, the detection sensor 1 outputs a pulse signal having a frequency corresponding to a measured amount such as vehicle speed or engine speed. The F / V converter 2 converts the pulse signal into a DC voltage. The DC voltage is input to the duty calculation circuit 3 and the sine and cosine of the rotation angle θ of the pointer A according to the DC voltage (sin θ and
cos θ) is obtained, and the corresponding predetermined duty is obtained from the characteristic of the duty which varies depending on sin θ and cos θ shown in FIG. The duty pulse generation circuit 4 generates a pulse signal based on this duty, and the pulse current based on the pulse signal is cross-coiled through the output circuit 5.
Supply to L ₁ and L ₂ . · The cross coil L _1, L ₂ is supplied pulse voltage having a duty than the duty pulse generating circuit 4, and is configured so that the pulse current flows through the cross coil L _1, L _2.

In the above configuration, the pulse signal from the vehicle speed sensor 1 is F /
It is input to the V converter 2, converted into a DC voltage, and input to the duty calculation circuit 3. The circuit 3 calculates θ according to the DC voltage and calculates the sine and cosine of the θ.
θ and cos θ) are calculated and the sin θ, cos
The duty according to θ is calculated. The duty pulse generating circuit 4 and an output circuit 5 generates a pulse voltage having the duty, the current i ₁ flowing by applying to the cross coil L _1, L _2, each cross coil L _1, L _2, i ₂
Is a value proportional to sin θ and cos θ, similar to the value shown in equation (4). Therefore, as described above, the angle .theta. In the synthetic magnetic field direction changes corresponding to the predetermined measurement amount, the pointer A rotates against the total dance spring C, and the rotation angle of the pointer A is read from the scale plate B. Thus, the measured amount can be recognized.

Since the rotation angle range of the pointer A is preset from the display range of the scale plate B, the duty calculation circuit 3 is set so that the pointer A rotates within this rotation angle range according to a predetermined measurement amount.
The duty is set according to sin θ and cos θ of the output rotation angle θ. Further, the pointer A is biased in the direction of the stopper pin P by the full spring C, and the pointer A contacts the stopper pin P when the measured amount is zero, and the pin P
Indicating the indicated value of the scale plate B (for example, "O" for a speedometer or the like, "E" for a fuel amount).

[Problems to be Solved by the Invention] In the above-described conventional configuration, pulse current is supplied to the cross coils L ₁ and L ₂ , and the duty thereof changes according to a predetermined measurement amount to drive the pointer A. Vibration is constantly applied to A. When it hits the stopper pin P, an abnormal noise is generated. Especially when applied to a speedometer, the pointer A is constructed so as not to separate from the stopper pin P when the power is normally turned on and at a low speed. Therefore, the pointer A vibrates to contact the pointer A and the stopper pin P. Repeated separation causes abnormal noise.

Therefore, it is an object of the present invention to provide a cross-coil type indicating instrument in which abnormal noise due to contact with a stopper pin is suppressed at an arbitrary rotation angle of a pointer according to a predetermined measurement amount.

[Means for Solving the Problems]

In order to solve the above problems, a cross-coil type indicator according to the present invention comprises a pair of cross-coils that intersect each other, and a pulse-current supply means for supplying the cross-coils with a pulse current having a duty corresponding to a predetermined measurement amount. A magnet rotor that rotates in a direction of a synthetic magnetic field generated by the cross coil by the pulse current, a pointer that is supported by the magnet rotor and rotates in cooperation with the magnet rotor, and a stopper pin that restricts rotation of the pointer. In the case of instructing a predetermined measurement amount from a deflection angle due to the rotation of the pointer, the pulse current supply means may cause the pointer rotation angle corresponding to the predetermined measurement amount to contact the pointer and the stopper pin when the pulse current is supplied. Supplying to the pair of cross coils by means of detection means for detecting a certain rotation angle range and output from the detection means Characterized in that it comprises a duty control means for reducing the duty of the two pulse currents in the same ratio that.

[Action]

In the above configuration, when the detection means detects that the rotation angle of the pointer according to the predetermined measurement amount is at the rotation angle at which the pointer and the stopper pin may come into contact with each other, the duty control means is driven to cause a pair of cross coils. Supply 2
The duty according to the predetermined measurement amount of one pulse current is reduced at the same ratio, and the pulse current with the reduced duty is supplied to the cross coil. This reduces the rotating torque of the pointer, weakens the contact force with the stopper pin, and suppresses the generation of abnormal noise.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a cross coil type indicator according to the present invention. In FIG. 1, the same parts as those in FIG. 5 are designated by the same reference numerals.

In FIG. 1, a detection circuit 6 that detects the magnitude of the DC voltage from the F / V converter 2 and a correction circuit that is controlled by the output of the detection circuit 6 and corrects the duty output from the duty calculation circuit 3 7 is provided.

In the above configuration, the detection circuit 6 drives the rotation angle of the pointer A based on the DC voltage corresponding to the predetermined measurement amount output from the F / V converter 2 and the pulse current is supplied to the cross coil. In the state, it is determined whether or not the pointer A and the stopper pin P are in an angular range in which they may come into contact with each other. If it is not within this angle range, the correction circuit 7 directly inputs the duty calculated by the duty calculation circuit 3 to the duty pulse generation circuit 4 without performing the correction operation, and the fifth
Similar to the figure, the pulse current of the duty is cross-coiled.
Supply to L ₁ and L ₂ . Further, if the DC voltage from the F / V converter 2 is within the angle range, the correction circuit 7 is operated by the output of the detection circuit 6, and the duty from the duty calculation circuit 3 has a predetermined coefficient β (0 <β <1. ) Is multiplied and the multiplied duty is input to the duty pulse generation circuit 4.

That is, as shown in FIG. 3, the pointer A corresponding to the measured amount
If the rotation angle θ of the angle range θ ₁ where the pointer A and the stopper pin P may come into contact, sin θ, cos θ
Is multiplied by a coefficient β according to the above to make the duty smaller than the duty corresponding to the measured amount. As a result, the rotating torque of the pointer A decreases, weakening the force with which the pointer A contacts the stopper pin P,
Suppress the generation of abnormal noise. At this time, since the duty of the pulse current supplied to each coil L ₁ and L ₂ is multiplied by β of the same coefficient, the combined magnetic field direction of the cross coil is the same direction as the pulse current with the original duty, and therefore The pointer A indicates the position of the rotation angle according to the measured amount, and the angle θ
_Even within the range of ₁ , no error occurs in the measurement amount instruction.

Further, as shown in FIG. 2, the duty calculation circuit 3, the detection circuit 6 and the correction circuit 7 in the embodiment of FIG. FIG. 4 is a flow chart showing the work performed by the CPU 8 in such an embodiment by the CPU 8. In the figure, the F / V converter 2 is omitted and the pulse signal from the detection sensor 1 is directly input to the CPU 8.

In the flowchart, first, the frequency of the pulse signal from the detection sensor 1 is calculated in step S1, and then the process proceeds to step S2 to calculate the rotation angle θ corresponding to the frequency. Then, in step S3, sin θ of this rotation angle θ
And duty according to cos θ, and then step
In S4, it is determined whether the duty is a duty corresponding to the angle range θ ₁ . If it is not within the angle range, the process proceeds to step S6 and the duty obtained in step S3 is output to the duty pulse generating circuit 4. If it is within the angle range, the process proceeds to step S7, the duty in step S3 is multiplied by the coefficient β, and this duty is output to the duty pulse generating circuit 4 in step S6.

In each of the above-described embodiments, the duty calculation circuit 3 and the CPU 8 consider the urging force so as to maintain a large torque enough to overcome the urging force of the total dance spring C when obtaining the duty corresponding to the rotation angle. Calculate.

[Effect] As described above, according to the present invention, it is possible to suppress an abnormal noise at the time of contact with the stopper pin due to the vibration of the pointer without causing a pointer pointing error.

[Brief description of drawings]

1 and 2 are views showing an embodiment of a cross-coil type indicating instrument according to the present invention, respectively, and FIG. 3 is a view showing characteristics of duty given to the cross-coil with respect to a rotation angle of a pointer in the instrument according to the present invention. FIG. 4 is a diagram showing a flow chart processed by the CPU in the embodiment of FIG. 2, FIG. 5 is a diagram showing a configuration example of a conventional instrument, and FIG. 6 is a cross coil with respect to a rotation angle of a pointer in the instrument of FIG. Showing the characteristics of the duty applied to the cross coil, FIG. 7 is a view showing the appearance of a general cross coil type indicator, and FIGS. 8 and 9 show the cross coil and the combined magnetic field direction for explaining the operation of the cross coil. It is a figure which respectively shows. 1 ... Detection sensor, 2 ... F / V converter, 3 ... Duty calculation circuit, 4 ... Duty pulse generation circuit, 5 ...
Output circuit, 6 ... Detection circuit, 7 ... Correction circuit, 8 ... CP
U, L ₁ , L ₂ ...... Cross coil, A ・ ・ ・ pointer, B …… scale, C …… all-spring, P …… stopper pin, Mg …… magnet rotor.

Claims (1)

[Scope of utility model registration request] 1. A pair of cross coils intersecting with each other, a pulse current supply means for supplying a pulse current having a duty corresponding to a predetermined measurement amount to the cross coils, and a direction of a synthetic magnetic field generated by the cross coils by the pulse currents. A magnet rotor that rotates around, a pointer that is supported by the magnet rotor and rotates in cooperation with the magnet rotor, and a stopper pin that regulates the rotation of the pointer, and indicates a predetermined measurement amount from the deflection angle due to the rotation of the pointer. In the cross coil type indicator, the pulse current supply means detects that the pointer rotation angle corresponding to the predetermined measurement amount is within the rotation angle range in which the pointer and the stopper pin may come into contact during pulse current supply. The detection means and the duty of the two pulse currents supplied to the pair of cross coils by the output from the detection means Flip cross coil type indicating instrument, characterized in that it comprises a duty control means for reducing a ratio.