JP2002137656A - Movable magnet type meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a movable magnet type meter capable of lowering costs. SOLUTION: This movable magnet type meter is provided with a rotor magnet 1 magnetized so that polarities of adjacent magnetic poles are different from each other, a pair of coils 5 and 6 arranged around the rotor magnet 1 while crossing their winding center axes C1 and C2 mutually at an angle other than a right angle, a controlling means 120 processing an input signal based on a measured quantity and supplying driving signals with different electrical angles to the respective coils 5 and 6 for rotationally driving the rotor magnet, and a pointer P turning by using the rotor magnet 1 as a driving source. When the number of magnetic poles in the rotor magnet 1 is represented by n while an acute angle formed between the winding center axes C1 and C2 crossing each other is represented by r, the acute angle r is set to be an angle found by driving 360 by 2n (n is an even number not less than 4).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a movable magnet type instrument for driving a pointer.

[0002]

2. Description of the Related Art As an instrument movement applied to a vehicle meter, for example, a moving magnet instrument of a cross coil type is generally well known. Such a movable magnet type instrument is also called an air core movement, in which a N- and S-polarized two-pole magnetized rotor magnet is housed in a space formed in a housing, and a rotor shaft fixed to the rotor magnet is fixed to the housing by a housing. Axial support, one end of which is projected outside of the housing, a pointer is attached, and a pair of coils are wound around the outer periphery of the housing so as to be orthogonal to each other. Specifically, 90 in electrical angle
A voltage signal having a sin waveform and a cos waveform having different degrees of phase is supplied, and a rotor magnet (pointer) is rotated around an axis by a composite magnetic field generated by each coil by supplying the driving signal. A driving signal is supplied to each coil. Is controlled in accordance with the measured amount such as the vehicle speed and the engine rotation, so that the pointer can be caused to angularly move in accordance with the measured amount.

In such a movable magnet type instrument, two
The main part of the movable magnet type instrument was covered with a shield case made of a magnetic material such as permalloy so that the rotor magnet which was poled was not affected by geomagnetism.

[0004]

By the way, in the above-mentioned movable magnet type instrument, a shield case made of a magnetic material such as permalloy is required in consideration of magnetic interference with a rotor magnet or the like and magnetic efficiency. For this reason, the number of parts could not be reduced, and magnetic materials such as permalloy forming the shield case were expensive, so that it was difficult to reduce costs.

The present invention has been made in view of this point, and a main object of the present invention is to provide a movable magnet type instrument capable of reducing costs.

[0006]

In order to achieve the above object, the present invention provides a rotor magnet which is magnetized so that adjacent magnetic poles are different from each other, and is provided around the rotor magnet and its winding is provided. A pair of coils whose central axes intersect non-perpendicularly, and control means for processing an input signal based on an amount to be measured, supplying drive signals having different electrical angles to each of the coils, and rotationally driving the rotor magnet. And a pointer that rotates using the rotor magnet as a drive source. When the number of magnetic poles of the rotor magnet is n and the acute angle formed by the winding center axis is r, the acute angle r is 360 / 2n ( n is 4 or more and a multiple of 2).

Further, a protection cover made of a non-magnetic material for protecting the coil is provided.

Further, a transmission means for transmitting the rotation of the rotor magnet to the pointer is provided between the pointer and the rotor magnet, and the pointer rotates at a lower speed than the rotor magnet through the transmission means.

[0009]

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

FIGS. 1 to 7 show a first embodiment of the present invention. FIG. 1 is a plan view of a movable magnet type instrument, FIG. 2 is a sectional view taken along the line A--A of FIG. 4 is a plan view showing the transmission means, FIG. 4 is a block diagram showing the control means, FIG. 5 is a waveform diagram of a drive signal supplied to the coil, and FIG. 6 shows the number of magnetic poles and the winding center axis of the coil in the present embodiment. FIG. 7 is an explanatory diagram showing a relationship between acute angles, and FIG. 7 is an explanatory diagram showing a relationship between the number of magnetic poles and an acute angle formed by a winding center axis of a coil in a modification of the present embodiment;
FIG. 7 is an explanatory diagram showing a relationship between the number of magnetic poles and an acute angle formed by a winding center axis of a coil in a modification of the present embodiment.

A movable magnet type instrument shown in FIGS. 1 and 2 has a rotor magnet 1 and a first shaft 2 supporting the rotor magnet 1.
A second shaft 3 provided side by side with the first shaft 2 at a predetermined interval, and supporting the first and second shafts 2 and 3 together with the rotor magnet 1 and a A housing 4 for accommodating a transmission mechanism to be driven, a pair of coils 5 and 6 wound around the outside of the housing 4,
6, a plurality of terminals T to which respective ends of the coils 5 and 6 are conductively connected, and a protective case 7 that covers a required portion of the housing 4 including a part of the housing 6. There is provided a pointer P attached to the tip, and transmission means TR interposed between the rotor magnet 1 and the pointer P and transmitting the rotation of the rotor magnet 1 to the pointer P.

The rotor magnet 1 is a disk magnetized in the radial direction with a total of four poles and an equal area ratio of 1/4 so that adjacent magnetic poles have different poles between the N pole and the S pole. Consisting of a plastic magnet (see Fig. 3)
The first shaft 2 is rotated (interlocked) with the first shaft 2
Through the housing 4.

The transmission means TR is fixed to the first shaft 2,
A first gear TR1 interlocked with the rotor magnet 1;
And a second gear TR2 that is fixedly connected to the second shaft 3 and is interlocked with the second shaft 3, and in the present embodiment, the first gear TR1 is a second gear TR2. T
It is formed with a smaller diameter than R2, and "14" continuous teeth (teeth) are formed on the outer periphery thereof. Also, the second gear TR2
Are formed with a larger diameter than the first gear TR1, and "56" continuous teeth (teeth) are formed on the outer periphery thereof.

The housing 4 is made of a synthetic resin.
The first and second frames 41 and 42 are divided and formed into a first frame 41 located on the middle and lower sides and a second frame 42 located on the upper side, and a cavity S is formed between the first and second frames 41 and 42. The hollow magnet S accommodates the rotor magnet 1 and the transmission means TR and supports the first and second shafts 2 and 3, and one end of the second shaft 3 projects outside from the housing 4. At the tip, as described above,
The pointer P is attached.

The coils 5 and 6 are located on the radial outer periphery of the rotor magnet 1 where the second gear TR2 is not disposed.
The winding diameter corresponding to the radial peripheral surface of the rotor magnet 1 is provided so as to gradually increase toward the rotor shaft 3. At this time, the rotors are arranged along the winding center axes C 1 and C 2 of the coils 5 and 6. The axis extending toward the shaft 2 intersects at the rotation center RC of the rotor magnet 1 (intersection point CP), and the acute angle r formed by the intersection of the winding center axes C1 and C2 at this time is set to approximately 45 degrees in this embodiment. Have been.

The direction of the winding center axes C1 and C2 of the coils 5 and 6 is the direction in which the coils 5 and 6 generate a magnetic field.

As shown in FIG. 6, in the case of the four-pole rotating magnet of the present embodiment, the acute angle r of 45 ° The angle is 45 degrees, which is an intermediate angle of 90 degrees formed between the pole and the N pole on the opposite side and one of the adjacent south poles.

For example, as shown in FIG. 7, in the case of a rotating magnet having six poles, the acute angle r is, for example, 180 degrees opposite to the south pole when the north pole is opposed to the coil 5, and the opposite south pole. And 30 degrees, which is an intermediate angle between the angles of 60 degrees formed by the adjacent one of the N poles.

The angle at which the acute angle r formed by intersecting the winding center axes C1 and C2 is 45 degrees may be formed by the arrangement of the coils 5 and 6 as shown in FIG.

A cup-shaped protective case 7 is mounted on the housing 4 around which the coils 5 and 6 are wound. In the present embodiment, a required area of the housing 4 excluding an area corresponding to the second gear TR2 is provided. That is, only the region of the housing 4 which is not included in the corresponding region of the second gear TR <b> 2 and is on the opposite side to the pointer P side is covered by the protective case 7. Protective case 7
Is made of a non-magnetic material such as aluminum, and is provided to protect the coils 5 and 6. Since the protective case 1 is formed without using such an expensive magnetic material, the cost can be reduced. The material of the protective cover 7 is not limited to aluminum but may be a synthetic resin.

The movable magnet type instrument configured as above is
As shown in FIG. 4, it is driven by a control unit 120 including a control unit 100 and a drive processing unit 110.

The control unit 100 comprises a microcomputer, a CPU for executing a control program, a ROM for storing the control program, a RAM for temporarily storing the processed data, and an external signal. Input interface (I / F), these CPs
U, ROM, RAM, and a bus that connects each of the interfaces are installed on the vehicle body side. In this case, a sensor 130 that detects rotation of the output shaft of the transmission and outputs a predetermined pulse signal is connected.

When a pulse signal (input signal based on the measured amount) from the sensor 130 is input, the control unit 100
Calculates the pulse period, converts the pulse period into an indicated position on a dial (not shown) described later, and performs a process of obtaining the indicated angle data of the pointer P on the dial.
The designated angle data is output to the drive processing unit 110 at the subsequent stage.

The drive processing unit 110 stores the RO data storing the energization amount data of the coils 5 and 6 according to the designated angle data.
A control unit which includes an M unit, a D / A conversion unit for converting an output value of each ROM unit into a corresponding analog amount, and a drive output unit for supplying a drive voltage corresponding to the analog amount to each of the coils 5 and 6; The designated angle data from 100 is supplied by the drive processing unit 110 to drive signals having different electrical angles (phase angles), more specifically, sin waveforms and cos waveforms having electrical angles different in phase by 90 degrees as shown in FIG. The signal is converted into a signal or a voltage signal having a waveform similar to the signal and supplied to the coils 5 and 6.

As a result, a combined magnetic field vector corresponding to the measured amount is formed by the coils 5 and 6, and the rotor magnet 1 is rotated by an angle corresponding to the measured amount according to the combined magnetic field vector. The pointer P is also rotated to indicate the measured amount on the dial.

In the case of this embodiment, in the transmission means TR, the number of teeth of the first gear TR1 is "14" and the number of teeth of the second gear TR2 is "56".
Since the gear ratio of No. 2 is set to 1/4, the transmission means TR functions as a deceleration transmission means, whereby the pointer P is decelerated to 1/4 with respect to the rotor magnet 1. In order to rotate P by a predetermined swing angle, the rotor magnet 1 needs a rotation angle that is four times the swing angle (rotation angle) of the pointer P. For example, when the input signal from the sensor 130 corresponds to the deflection angle of the pointer P of 90 degrees, it is necessary to rotate the rotor magnet 1 by 360 degrees in mechanical angle. Therefore, the control unit 120 rotates the rotor magnet 1 by 360 degrees in mechanical angle. As a drive signal for rotation, a drive signal corresponding to an electrical angle of 2π (one cycle) is repeatedly supplied to each of the coils 5 and 6 twice.

Therefore, in the case of this embodiment, the electric angle is 2π.
The rotation angle of the rotor magnet 1 obtained by supplying a drive signal corresponding to a minute (hereinafter referred to as 2π signal supply) is a mechanical angle of 180 degrees, and the deflection angle (rotation angle) of the pointer P through the transmission means TR is the same. The mechanical angle is 45 degrees, and the deflection angle of the pointer P larger than 45 degrees, for example, 90 degrees, 135 degrees, 180 degrees
In order to obtain a degree of swing angle, signal supply for 2π is continuously and repeatedly supplied.

With the above configuration, the rotor magnet 1 can be driven with less influence from the earth magnetism and the like than in the case where the rotor magnet 1 is bipolar magnetized. Therefore, even if it is not necessary to cover the rotor magnet 1 with a magnetic material, the rotor magnet 1 can be driven, and only for the purpose of protecting the coils 5 and 6 from physical damage or the like,
It is only necessary to form and provide the protective cover with an inexpensive material other than a magnetic material, and the cost can be reduced as compared with a conventional movable magnet type instrument.

When the rotor magnet 1 is rotationally driven by supplying drive signals having different electrical angles to the pair of coils 5 and 6,
The number n of the magnetic poles of the rotor magnet 1 may be 4 or more (a natural number (N) times 2), and at this time, the pair of coils 5 and 6
When the number of magnetic poles is “4”, the acute angle r formed by intersecting the magnetic field directions generated by supplying the drive signal to
As shown in FIG. 6, the angle is approximately 45 degrees as in the present embodiment,
When the number of magnetic poles is "6", the angle may be set to 30 degrees as shown in FIG. 7, and the acute angle r may be set to half (1/2) of (360 degrees / number of magnetic poles). Although not shown, when the number of magnetic poles is “8”, the acute angle r is (360 degrees /
It may be set to 22.5 degrees which is half (1/2) of the number of magnetic poles n).

In this embodiment, the transmission means TR is constituted by the two gears TR1 and TR2. However, the number of gears constituting the transmission means TR is arbitrary. For example, FIG. As shown in FIG. 9, the transmission means TR is held together with the rotor magnet 1 so as to be independently rotatable with respect to the first shaft 2 and rotates together with the rotor magnet 1, and a second gear TR 11. A second gear TR12 fixed to the shaft 3 and rotating together with the second shaft 3;
12 and the second gear TR12
A third gear TR13 rotating together with the first gear TR
And a fourth gear TR14 fixed to the first shaft 2 together with the first shaft 2 and rotating together with the first shaft 2.
The rotation of the first gear TR11 interlocked with the second gear TR
2 and the rotation of the second gear TR2 is transmitted to the third gear TR1.
3, the pointer P may be transmitted to the fourth gear TR14, thereby driving the pointer P mounted on the first shaft 2.

As described above, the provision of the transmitting means TR for decelerating rotation can further suppress the influence of the geomagnetism on the rotor magnet 1 and provide a movable magnet type instrument capable of giving a high-precision instruction. it can.

The transmission means T described in each of the above embodiments
A configuration in which the pointer P is directly provided on the first shaft 2 without providing the R may be adopted.

In each of the above embodiments, the protective case 7 is provided. However, when it is not necessary to protect the coils 5, 6, etc., the shield case made of a magnetic material is not required.
Further, the protective case 7 need not be provided. With this configuration, the number of components can be reduced. It is also possible to reduce costs.

[0034]

As described in detail above, it is possible to provide a movable magnet type instrument which can achieve the intended purpose and can reduce the cost.

[Brief description of the drawings]

FIG. 1 is a plan view of a movable magnet meter according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a plan view showing a transmission unit.

FIG. 4 is a block diagram showing control means.

FIG. 5 is a waveform diagram of a drive signal supplied to a coil.

FIG. 6 is an explanatory diagram showing a relationship between the number of magnetic poles and an acute angle formed by a winding central axis of the coil in the embodiment.

FIG. 7 is an explanatory diagram showing a relationship between the number of magnetic poles and an acute angle formed by a winding center axis of a coil in a modified example of the embodiment.

FIG. 8 is an explanatory diagram showing a relationship between the number of magnetic poles and an acute angle formed by a winding center axis of a coil in a modification of the embodiment.

FIG. 9 is a sectional view of a movable magnet type instrument according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 rotor magnet 5, 6 coil 7 protective cover 120 control means C1, C2 winding center axis n number of magnetic poles P pointer r acute angle TR transmission means

Claims (3)

[Claims] 1. A rotor magnet that is magnetized so that adjacent magnetic poles are different from each other, a pair of coils provided around the rotor magnet, and whose winding central axes intersect non-perpendicularly, Control means for processing the input signal based on the amount and supplying drive signals having different electric angles to each of the coils to rotationally drive the rotor magnet; and a pointer for rotating the rotor magnet as a drive source. When the number of magnetic poles of the rotor magnet is n and the acute angle formed by the intersection of the winding center axes is r, the acute angle r is an angle determined by 360 / 2n (n is 4 or more and a multiple of 2). A movable magnet type instrument characterized by the following. 2. The movable magnet type instrument according to claim 1, further comprising a protective cover made of a non-magnetic material for protecting said coil. 3. A transmission means for transmitting the rotation of the rotor magnet to the pointer between the pointer and the rotor magnet, wherein the pointer rotates at a lower speed than the rotor magnet through the transmission means. The movable magnet type instrument according to claim 1 or 2, wherein: