JPH0231307A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain the magnetic head small in temperature dependency by including a part, in which magnetic saturation is easily generated, into one part of a magnetic circuit. CONSTITUTION:The magnetic head is composed of an I core 4, an L core 4 to be composed of a ferrite, a back core 2, whose saturation magnetic flux density is effectively low, to be composed of the sintered body of the ferrite and non-magnetic ceramics and a gap part 1. Since the saturation magnetic flux density is small for the back core 2, a magnetic flux goes to be constant in case that recording and magnetizing force over a certain degree is loaded. The recording and magnetizing force for the constant magnetic flux is determined according to the product of a recording current and a coil. Here, since the recording current is caused to be 10mApp, for example, the magnetic flux goes to be constant. Then, with being reflected by this constant magnetic flux, an output voltage goes to be constant without depending on a temperature or the recording current. Thus, the temperature dependency can be decreased for the output voltage of the magnetic head.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic head for a magnetic recording device.

[Conventional technology]

An example of a conventional magnetic head is shown in FIG. This magnetic head is composed of an echo core 4, an L core 5, and a back core 3 made of ferrite, and has a gap 1. In this example, recording and reproduction are performed by the same magnetic head. By passing a recording current through the winding 6, a magnetic field is generated in the gap 1, and recording is performed. Further, during reproduction, the magnetic flux of the recording medium detected through the gap 1 applies a voltage to the winding 6.

[Problem to be solved by the invention]

However, in a magnetic hesedo with such a configuration, as is clear from the relationship diagram of the recording current and output voltage in a conventional magnetic head shown in Figure 7, the recording current is not kept constant at the actual current value shown in the diagram. However, there is a problem in that the output voltage fluctuates significantly due to temperature changes, and the performance of the recording device also has a large temperature dependence.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and an object of the present invention is to provide a magnetic head with less temperature dependence.

[Means to solve the problem]

The magnetic head of the present invention is a magnetic head used in a magnetic recording device, and is characterized in that a portion of the magnetic circuit includes a portion where magnetic saturation is likely to occur.

〔Example〕

FIG. 1 is a schematic diagram of an embodiment of the present invention.

This magnetic head consists of an echo core 4 and an L core 5 made of ferrite, a back core 2 made of a sintered body of ferrite and nonmagnetic ceramics and having an effectively low saturation magnetic flux density, and a gap portion 1.

Before explaining the embodiments, the causes of the temperature dependence of the output voltage will be outlined.

The soft magnetic material used in the magnetic head, such as the ferrite used in this example, must have a large magnetic permeability, so a material whose Curie point is slightly higher than room temperature is used. be done. In the case of ferrite, the temperature is over 100 degrees Celsius. However, in general, magnetic permeability has a large temperature dependence near the carry point and increases as the temperature approaches the carry point. In such a magnetic head made of a material whose magnetic permeability is highly dependent on temperature, even if the magnetomotive force applied to the head during recording is constant, the recording magnetic field generated in the gap will change due to the increase in magnetic permeability as the temperature rises. It becomes larger because the magnetic resistance decreases. This is the cause of the temperature dependence of the output voltage. As a countermeasure against this problem, it is sufficient to make the write magnetic field generated in the gap constant regardless of the temperature.

Now, in this embodiment, since the back core 2 has a small saturation magnetic flux density, the saturation magnetic flux density is small to a certain extent as shown in the relationship diagram between the recording magnetomotive force and the magnetic flux in the magnetic circuit shown in FIG. 2 for explaining one embodiment of the present invention. If the above recording magnetomotive force is applied, the magnetic flux becomes constant at φS. Note that φS is equal to the saturation magnetic flux of the back core. or,
The recording magnetomotive force is the product of the recording current and the number of turns. In Figure 3,
As shown in the relationship diagram between recording current and output voltage in one embodiment of the present invention, reflecting the fact that the magnetic flux is constant at φS,
The output voltage remains constant regardless of temperature or recording current at a certain recording current, in this example, 10 mApp or more.

FIG. 4 is a schematic diagram of another embodiment of the invention.

In this embodiment, since there is no back core, a member with a low saturation magnetic flux density is sandwiched between the two cores.

FIG. 5 is a schematic diagram of another embodiment of the invention. In this embodiment, magnetic saturation is caused by providing a portion 8 with a reduced cross-sectional area in a part of the magnetic circuit.

Note that although the output voltage has been explained, the temperature dependence of other characteristics is also improved.

〔Effect of the invention〕

As described above, according to the present invention, a part of the magnetic head is provided with a part where magnetic saturation is likely to occur, and during recording, magnetic saturation is caused in this part to make the magnetic circuit constant magnetic flux, that is, substantially The temperature dependence of the output voltage of the magnetic head can be reduced by keeping the magnetic flux flowing through the magnetic circuit constant, and by keeping the recording magnetic field generated in the gap constant regardless of temperature etc., depending on the value of the saturation magnetic flux in the part where magnetic saturation is likely to occur. This has the effect of eliminating the

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between recording magnetomotive force and magnetic flux in a magnetic circuit for explaining one embodiment of the present invention. FIG. 3 is a diagram showing the relationship between recording current and output voltage in one embodiment of the present invention. FIG. 4 is a schematic diagram of another embodiment of the present invention. FIG. 5 is a schematic diagram of another embodiment of the present invention. FIG. 6 is a schematic diagram of a conventional magnetic head. FIG. 7 is a diagram showing the relationship between recording current and output voltage in a conventional magnetic head. 1... Gap 2... Back core 3 with low saturation magnetic flux density... Back core 4... Eco core 5... L core 6... Winding 7... Member 8 with low saturation magnetic flux density ...more than the portion with a reduced cross-sectional area Applicant Seiko Epson Co., Ltd. agent Patent attorney Kizobe Suzuki and 1 other person! Gear v7 Diagram Hair 4 Lifting 1 Power Diagram 2 Diagram Diagram Diagram Diagram Kichiran Mitsuru Diagram

Claims (1)

[Claims] A magnetic head used in a magnetic recording device, characterized in that a part of its magnetic circuit includes a portion where magnetic saturation is likely to occur.