JPS59501971A - Brushless DC motor with reversing magnet cup - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Background of the invention of brushless DC motor with reversing magnet cup The present invention relates to brushless DC motors, particularly for use in rotating disk systems. Related to brushless DC motors designed for Furthermore, the present invention A bra that can balance itself as a unit with seven balanced states. Related to Sires DC motors.

Brushless DC motors are used in electronic devices with rotating elements such as magnetic disk storage systems. The use of data has become commonplace. There are two reasons for this. That is, ( 1) The rotational speed of such equipment must be accurately controlled, and brushless direct Flow motor, together with its electronic control system, precise speed control is easily achieved and (2) the brushless DC motor has a mechanical support structure. body part, thereby saving both space and cost.

In some cases when brushless DC motors are used, the rotating elements of the motor are at an acceptable level. must be balanced. If the correct balance level is not achieved, Electronic devices using motors may not be able to function as desired or may be installed due to an imbalance. The life of the motor is shortened due to stress on the bearings from the vibration.

Balanced operation of a brushless DC motor involves balancing each rotating element of the motor individually. This has been realized with prior art. Each rotating element is then assembled and The correct balancing behavior of the assembled unit is checked. other additional Balance movements are often required.

If the motor is used, e.g. for its maintenance or for the maintenance of the entire system in which it is used. If it has to be disassembled for action is required. This means that the individual components of the motor are This is because they are no longer reassembled as accurately as before. This additional balance step One method has been used in the prior art to avoid this drop. That is, (1) Individual motor elements are manufactured to sufficient tolerances and therefore component reassembly is not possible. proper balance is ensured regardless of the method of and alignment holes are selectively placed within the component, which allows the A fixed relationship is maintained between them. Provide sufficient tolerance, use keybins or adjustment holes This allows the motor to be reassembled without the need for rebalancing. However, these methods are disadvantageous because they increase the cost of the motor.

Therefore, what is needed here is low cost and the desired balance of the rotating element. A simple brushless DC motor where maintaining the lance is no longer a problem. This includes designing data.

3 Summary of the invention The present invention balances the rotating elements of the motor before they are incorporated into the motor. In addition, it is possible to use a brake that does not require extra balancing operations after motor assembly. The purpose is to provide a SIRES DC motor.

The present invention further provides for disassembly, if necessary, without balancing after reassembly. The purpose is to provide a motor that can be reassembled.

The present invention provides a brushless DC motor in which all rotating elements can be assembled as subassemblies. The design of the data satisfies the above objectives and other objectives. Here the above The small assembly is balanced and incorporated as a fixed element of the motor. subordinate balanced before being incorporated into the stationary phase, and there are no additional parts. The rotating element does not need to be balanced after assembly with the stationary element.

Furthermore, since the rotating elements of the motor are defined as balanced subassemblies, Therefore, there is no need to disassemble the assembly. Therefore, whenever it is necessary to disassemble the motor, In addition, the balanced subassembly can be immediately removed from the fixed elements of the motor. The reeds can also be reinstalled. Moreover, balanced sub-assemblies can be reused. Never requires balancing.

The rotating elements included in the balanced I-drive assembly of the present invention include a shaft and a shaft. a spindle hub (to which the rotating disc or discs are fixed) and a cover. and a cup assembly (to which the permanent magnet is fixed). Traditional methods The cup assembly is secured to the end of the shaft using a cup adapter and spins Whereas the dollar hub had to be fixed to the other end of the shaft, the present invention The top assembly and spindle hub are conveniently secured to the same end of the shaft. Give it your own small assembly. Therefore, once assembled and balanced And this subassembly never needs to be disassembled.

Brief description of the drawing The above objects and other objects, as well as advantages and features of the present invention can be understood from the following drawings. It will become clearer from the following description of preferred embodiments, which are described with reference to them.

Figure 1 is a cross-sectional view of a prior art brushless DC motor, which requires balance. and the manner in which these elements are assembled together with the stationary elements of the motor. It shows.

FIG. 2 is a cross-sectional view of a brushless DC motor designed according to the present invention. The following description shows the same details as in Figure 1 and is considered the best at this time for practicing the invention. It provides a method for This description is intended to explain the general principles of the invention. Even if it is given as Yes, there are no restrictions whatsoever. The true scope of the invention is determined by the appended claims. It may be helpful to refer to the

In order to more fully understand the features and advantages of the present invention, reference may be made to the prior art. A more detailed explanation of conventional brushless DC motors used for disk drive applications. First of all, it is necessary to The rattling motor is shown in cross-section in FIG. Rotation of motor The element is shaft 10. Spindle hub //, cup adapter 72. and rotating magnet Consists of 3 stone cups. The solid rectangle /4 and /j are shown in the diagram. Several permanent magnets are fixed to the inner edges of the rotating magnet cup/3.

The fixed elements of the motor are arranged around the periphery as illustrated as rectangles/7 and/or rectangles. It consists of a spindle housing with a plurality of motor magnets. These etc. The magnet is usually an electromagnet that supplies a direct current of the desired polarity to a coil associated with the magnet. It is excited by energizing the coil winding.

The rotating element shaft 10 is a ball bearing,,20~! 7. Spindle of fixed element Supported by Usingu Otsu.

A ball bearing can be either a rotating element, a stationary element, or neither. It can be thought of as the 7th part of the ), 2. 27 rotates together with the shaft 10, then remove it and stand still. In addition, the ball bearings 20 to 23 rotate between the inner and outer races to support the load of the rotating elements. It's a good thing. Although ball bearings are shown in the figure, this means that suitable rotating bearings are mechanically For example, for roller bearings, ball bearings, square pin bearings, etc. It's not.

The mechanical structure of the device in which the fixed element spindle housing/2 uses a motor It is attached to the mount 30 of. The method of fixation is not critical to the invention.

In conventional DC motors (not brushless motors), the magnet is It forms part 7 of the fixed part. These magnets are either permanent magnets or electromagnets. , excitation by passing an appropriate DC current through a coil installed inside the motor housing. be done. The motor windings form part of the rotating portion of the motor. Direct current flows through a commutator, i.e. Winding through a grooved and insulated segment of copper (or other conductive material) The commutator is connected to a rotating system through carbon brushes that brush against the commutator. It will be made into part 7 of the shaft. Pairs of commutator segments connect electrically to individual pairs of motor windings. connected to. / The current in the motor windings of the pair generates a magnetic field, which opposing the magnetic field of the fixed magnet in the fixed part of the shaft, thus causing rotation of the shaft i) Armed forces will occur. As the shaft and therefore the commutator rotate, different motor windings Therefore, rotation of the shaft continues. Conventional DC motor 7 In contrast, the fixed elements of a brushless DC motor are 7 parts of the fixed element of the motor. Also, the permanent magnet is part of the rotating element. To develop most of the torque , the permanent magnets are typically spaced as radially as possible from the centerline of the shaft. There is. Therefore, rather than simply attaching a magnet to the side of shaft 10, as shown in FIG. As shown, magnet cup assembly 3 is used to move the magnets to the maximum radial spacing position. so that it is placed in

Thus, in FIG. Located at a large distance, opposite the motor windings /7 to /g. Motor winding suitable for DC The magnetic force is electrically switched to a pair of wires, which generates a magnetic force t1, which is generated by a permanent magnet, This causes rotation of all rotating elements of the motor.

It is advantageous if the rotational speed of a brushless DC motor can be easily measured. for example , the grooved plate can be part of the rotating part of the motor. The grooves in the plate are the light source. and the photosensitive diode, it has a frequency proportional to the rotational speed of the motor. A pulse train is generated. Switching the current to the moi winding using this pulse train Therefore, the speed of the motor can be controlled accurately.

In this way, the speed of the brushless DC motor can be accurately controlled. This allows such motors to be used in many applications, such as traditional DC motors such as disk drives. It becomes possible to use it for applications that could not be done with data. However, it takes The application also requires precise balancing of rotating elements. As already explained, the Although it is possible to accurately balance the motor shown in Figure 1, This is what is lost when the motor is disassembled. To explain this further, Shaft 10 and spindle hub // (see Figure 1) manufactured from separate pieces of metal be done. Next, this spindle Permanently fixed to the shaft 10 by the interference fit be done. The resulting subassemblies are then dynamically balanced. this rose A speed motion typically involves rotating an object at a desired speed, e.g. This is done by measuring the amount of imbalance using light or the like. object is stopped , the amount of material equal to the imbalance is usually caused by surface treatment or drilling. is removed from the appropriate part of the object. The object is rotated again and some imbalance occurs. measurement is performed again.

This process is repeated until the amount of residual imbalance is within predetermined limits.

Cup adapter/2 and rotating magnet cup/3 must be balanced in the same way. Must be done. Once all rotating elements 10~/j are balanced, their the law of nature The elements are reassembled with fixing elements to achieve a complete motor assembly. For use Therefore, depending on the amount of imbalance allowed, the resulting complete motor assembly may require further balancing. Also, as already explained, the mode If the motor still has to be disassembled, the cost used in the manufacture of the rotating parts must be Depending on the circumstances, the balancing operation may be required again during reassembly. There is enough.

FIG. 2 is a sectional view of a brushless DC motor constructed in accordance with the present invention. Is it a figure? As can be seen, the rotating magnet cup 'I-3 is attached to the shaft along with the permanent magnets p+~gt. Attached to the spindle hub // (as shown in the prior art) in place of the opposite end of the The motor winding ≠ 7~ttg is attached to the spindle housing ≠ the spindle of Otsu. Located at the hub end. Magnet Hiroshi≠～1l-j (These are single donut-shaped cores a piece, selectively magnetized, or a plurality of individually magnetized pieces) motor winding 417~≠ which selected outer surface. The juxtaposition (depending on the rotational position of the shaft) is maintained. Shaft 10 is an axis Rotate j0 to Akashi. The disk j2 usually has a central hole jlI inside it. When the motor is used to drive the disk, it is attached to the spindle hub//.

These features of the present invention allow all of the rotating elements of the motor, namely the shaft 10. Spindle hub 772 rotating magnet cup≠3. and permanent magnet G≠~4', 5- is This makes it possible to manufacture the product using conventional manufacturing methods. so that the elements are balanced , so no extra cost is required. Then the rotating element is a single compact assembled into subassemblies. This subassembly is balanced as described above. is taken. The balanced subassembly is then installed on the fixed element of the motor. It can be done.

A unique feature of the invention is that once the rotating assembly is assembled into a subassembly, , there is no need to disassemble them. Therefore, once the balance is Once taken, the rotating subassembly can be rotated without the need for extra balancing operations. This feature can be installed, removed, and reinstalled in only one subassembly. All you need to do is take a balance, and you only need to perform a 7-degree balance operation. This greatly reduces manufacturing and maintenance costs for data assembly.

Although it is a simple change at first glance, rotating magnet cup / 3° permanent magnet / G ~ / 3. and mo Connect the motor windings /7 to /g to the spindle hub end of the motor housing shown in Figure 2. This is a significant advance over the prior art.

All disc-driven brushless DC motors according to the prior art known to the applicant are A magnetic cup/3 is placed on the opposite end of the shaft from the handle, and this It is possible to distribute the inertia of the motor more evenly along the length of the motor. . Such an inertial force distribution is necessary and consistent, as shown in the prior art. , thus the stress of the rotating shaft along the entire length of the shaft is properly distributed and the motor The moment of inertia is maintained more or less centered within the data housing. Become. As shown in Figure 2, most of the motor's inertia is tied to the end of the shaft. By doing so, the problems suggested by the prior art are not caused. against this The reason is that a suitable dynamic buffer can be By achieving and maintaining the lance, if not, uneven motor Ignoring inertia force distribution (i.e. most of the inertia of the motor coupled to the shaft/end) We believe that this reduces the wear and distortion that would otherwise make the product impossible. It is being In any case, what has been achieved so far using the motor configuration shown in Figure 2? The results obtained are surprisingly satisfying and predictable.

Therefore, the present invention, because of the advantages it provides, is a It is planned for use in many disk-driven products.

'FIGURE I.

FIGURE 2゜ international search report

Claims (1)

[Claims] /, housing, a shaft secured for friction-reducing rotation within the housing; a motor winding disposed around an exterior surface of the housing; a spindle hub fixed to the first end of the shaft; A magnetic cup fixed to the spindle hub and a shell, the magnetic cup being fixed to the magnetic cup. at least one permanent magnet defined by said motor winding. A brushless DC motor that maintains a selected and juxtaposed non-contact relationship with the external surface of the wire. Data. 2. The shaft, spindle hub, and magnetic cup are the first mechanical assembly. assembly, and said housing and motor windings are connected to a second mechanical assembly. Additionally, the first assembly is attached to the second assembly. The motor is removably secured to permit selected disassembly and reassembly of the motor. The brushless DC motor according to claim 1. 3. said first assembly rotates about the longitudinal axis of said shaft; The brushless DC motor according to claim 2, which is dynamically balanced. O Hiro: The second assembly is such that the first and second assemblies are fixed together. Claim 3 further comprising a friction reducing bearing supporting said shaft. The brushless DC motor described in . It is provided for use in a disk drive and has a motor winding, and the winding selectively spaced around an outer surface of the housing; a device for securing to the disk drive; a shaft rotatably fixed to the housing; and a shaft fixed to a seventh end of the shaft. inside the disk whose upper side is to be driven by said disk drive. The spindle is adapted to engage the core and includes seven permanent magnets, The magnet maintains a selected and juxtaposed non-contact relationship with the outer surface of the motor winding. An improved, low cost, magnetic cup positioned to Topless DC motor. B, the above-mentioned chanet, spindle hub, and magnetic cup are assembled into the first assembly. the shaft before being inserted into the housing and securing the first assembly to the housing. The improved formula according to claim 5 is dynamically balanced around the circumference of a solid axis. Low cost, compact brushless DC motor. ／≠ 7. said first assembly is selectively detached from said housing; The motor is disassembled for maintenance or other purposes, and the first assembly is disassembled. The first assembly can be reassembled without the need for initial disassembly. The improvement according to claim 4, which does not need to be dynamically balanced after the performance operation. Formula low cost, con i? A simple brushless DC motor. g. The motor is fixed to a housing and an outer surface of the housing, and a fixed winding located substantially in a plane perpendicular to the central longitudinal axis of the housing; a shaft, a spindle hub, and an inner diameter greater than or equal to the diameter of said housing and winding; It has a magnetic cup, (,) A plurality of permanent magnets are selectively spaced around the inner peripheral surface of the magnetic cup. (b) securing said spindle hub to said first end of said shaft; the step of wearing (c) Fix the magnetic cup to the shaft side of the spindle hub, and Shape the first assembly consisting of the shaft, hub and magnetic cup. the steps to (d) dynamically moving said first assembly about a central longitudinal axis of said shaft; A balancing step, (e) rotatably and removably securing said first assembly to said housing; , so that the longitudinal axes of said housing and shaft coincide, thus The magnet of the magnet cup is substantially flush with the motor windings without physically contacting the windings. Steps that rotate within A manufacturing method for low-cost brushless DC motors that can be used to power contact/force. /