CN1808855A - Small-sized motor with decelerator - Google Patents

Abstract

In order to secure a sufficient reverse rotation resistance by employing an inexpensive material for a worm wheel even if its strength is low without requiring an additional working process and an additional mechanism or component. The invention integrally assembles a motor part and a reduction gear part by accommodating in a gear case a metal worm connected to a motor shaft of the motor part and a worm wheel meshed with the worm. When the motor shaft rotates, the rotation leads to the reduced rotation of the worm wheel through the medium of a metal worm, thereby driving an external output shaft coupled to the worm wheel. The metal worm is finished by form rolling only. The worm wheel is formed by molding polyacetal taken as its material. The advancement angle of the worm gear falls between 3 degree and 3 degree 30''.

Description

The miniature motor of band decelerator

Technical field

The present invention relates to motor spindle its rotation of when rotation and make the worm gear reducer rotation by worm screw, thus the band decelerator miniature motor that joining output shaft is with it driven.

Background technology

For the miniature motor such as the employed band decelerator of automobile electric window, it has degeneration-resistant commentaries on classics special requirement.So-called degeneration-resistant commentaries on classics mainly is meant from motor one side can high efficiency drive vehicle window, though the external force that acts on fenestrate deadweight and window is opened in vehicle window one side on the other hand, the ability that motor can not reverse yet, window also can not be opened.

As everyone knows, in the past, the degeneration-resistant commentaries on classics in order to ensure the miniature motor of being with decelerator will be provided with clutch or brake component (with reference to patent documentation 1 or patent documentation 2).For example, in patent documentation 2, the front end of the motor spindle that is integrally formed with it worm screw is installed the resin component (polyimides) of special substance, in the occasion that produces rotation from worm gear one side, thus owing to the effect that is delivered to the axial thrust on the motor spindle with brake disc that resin component contact between generation frictional force braked and prevent to rotate.But these mechanisms or parts are set will influence the raising of the miniaturization of decelerator unit, reliability and the reduction of cost.In addition, because main shaft and worm screw are one, thereby are subjected to and can't do the worm screw external diameter bigger, the restriction such as little grade of the choice of the specification of tooth.

In addition, people know, in order to guarantee degeneration-resistant commentaries on classics, worm screw are carried out the surface roughness of surface treatment with the increase flank of tooth, thereby improve the technology (with reference to patent documentation 3 or patent documentation 4) of coefficient of friction.But this needs certainly and carries out the surface-treated manufacturing procedure, thereby the processing cost height.

In addition, as the worm gear that is activated with worm engaging,, using materials such as glass fibre filled nylon in order to guarantee its intensity.But its fee of material height needs higher cost.But also exist, and, glass fibre causes problems such as worm screw one lateral wearing because of scratching the worm screw surface because of the form accuracy difference produces noise.

[patent documentation 1] spy opens the 2001-346355 communique

[patent documentation 2] spy opens the 2002-369447 communique

No. 2636958 communique of [patent documentation 3] Japan Patent

[patent documentation 4] spy opens the 2003-97671 communique

Summary of the invention

The present invention proposes in order to address the above problem, its purpose is, do not need to increase manufacturing procedures such as worm screw surface treatment, do not need to increase mechanism or parts such as clutch or brake component, though and the low but cheap material of worm gear working strength, thereby guarantee enough degeneration-resistant commentaries on classics.

In addition, the present invention also aims to, the low material of worm gear working strength is not only in order to reduce cost, but also can therefore reduce noise and reduce the wearing and tearing of worm screw one side.

The miniature motor of band decelerator of the present invention is that motor part and decelerator portion are assembled into one, described decelerator portion be with the motor spindle that is connected in this motor part on the worm screw of metal manufacturing and the worm gear that is engaged be contained in the gear box and constitute, when motor spindle rotates, its rotation makes the worm gear reducer rotation via worm screw of metal manufacturing, thereby joining output shaft is with it driven.It is characterized in that the worm screw of this metal manufacturing is only finished fine finishining through roll extrusion, worm gear is to use polyacetals to form as its material and to it and forms, and the spiral lead angle of worm gear pairs is in 30 minutes scope of 3 degree～3 degree.

According to the present invention, owing to do not use clutch and brake component etc. and simple in structure, thereby degeneration-resistant commentaries on classics can change because of the change of environmental condition hardly, in addition, owing on worm screw, do not carry out surface treatment, thereby degeneration-resistant commentaries on classics can reduce hardly along with the time.In addition, owing to do not use clutch and brake component, thereby can reduce the parts cost, owing to change the material of worm gear into the resin more cheap (polyacetals) than glass fibre filled nylon, thereby can reduce the cost of raw material.

Description of drawings

Fig. 1 is the three-dimensional exploded view that is assembled with as the miniature motor of the band decelerator of the worm and worm wheel of feature of the present invention.

Fig. 2 is the accompanying drawing that the formation as the worm screw of feature of the present invention and the worm gear that is engaged with is described.

Fig. 3 is that spiral lead angle γ is set fixed value, is transverse axis with the coefficientoffriction, is the curve chart of the longitudinal axis with the efficiency eta.

Embodiment

The invention is characterized in the formation of the worm screw that is fixed on the motor spindle and the worm gear that is engaged with, and before being explained, roughly the miniature motor of the band decelerator that is assembled with them is carried out general description in conjunction with Fig. 1.Fig. 1 is the three-dimensional exploded view that is assembled with as the miniature motor of the band decelerator of the worm and worm wheel of feature of the present invention.

The miniature motor of illustrated band decelerator is assembled into one by motor part and decelerator portion and forms.Motor part can be made of common small direct current motor.As decelerator portion, be connected in worm screw on the motor spindle and the worm gear that is engaged with etc. and be contained in its gear box.In addition, buffer unit is housed in the worm gear, worm gear connects with output shaft through buffer unit.They are supported rotatably centering on fixed axis.The Plug Division by the connector case lid among the figure provides power supply to motor, and it still is used for taking out the electric connection part of motor rotating signal.

Owing to as above constitute, thus when motor driven, the motor spindle rotation, this rotation makes the worm gear reducer rotation via worm screw, and then buffer unit and output shaft are rotated.Like this, along with the rotation of this output shaft, the window-glass of automobile is opened and closed via not shown driving mechanism.

Fig. 2 is the accompanying drawing that the formation as the worm screw of feature of the present invention and the worm gear that is engaged with is described.Chimeric being fixed on the motor spindle of worm screw of metal manufacturing as shown in the figure, (for example iron).Thisly fixing can be as usually process and on worm screw, to have embedded hole implementing annular knurl on the motor spindle, add in the Ministry of worker and fix by worm screw being entrenched in this annular knurl.Like like this, worm screw and motor spindle are constituted separately, can make external diameter of worm screw and main shaft external diameter not have dependence, even if the motor of minor diameter main shaft also can make up with large diameter worm screw.

Worm screw used in the present invention is only finished fine finishining by roll extrusion.Owing to the surface treatment of not passing by to be carried out, thereby not only can reduce processing charges and can make steady quality.During particularly with continuous roll extrusion autofrettage roll extrusion worm screw, can also reduce cost significantly.Roll extrusion autofrettage itself is known as the manufacture method of worm screw continuously, but the round iron rod that described here is with cut-and-dried length, in the middle of the roll die of two rotations, pass through, make pole be the manufacture method that is sent when worm forms on rotation limit, limit.It is cut into set length, carry out being entrenched on the main shaft after the perforate processing.

As with the material of the worm gear of worm engaging, be not glass fibre filled nylon in the past, the back use but polyacetals that will be cheap is shaped.Like like this, the material of worm gear is not used glass fibre, thereby improves the useful life of mould, and has effects such as precision height, noise are low, stable performance, long service life.

In addition, the spiral lead angle (torsion angle) of worm wheel body of the present invention is guaranteed degeneration-resistant commentaries on classics with this in 30 minutes scope of 3 degree～3 degree.The spiral lead angle of worm screw and the torsion angle of worm gear form with identical angle.

Below, with regard to worm screw as mentioned above only by roll extrusion finish fine finishining, the worm gear material uses spiral lead angle this three's in 30 minutes scopes of 3 degree～3 degree of polyacetals and worm wheel body combinations that the guaranteed problem of degeneration-resistant commentaries on classics is described.We know that the efficiency calculation formula of worm wheel body can be represented with following formula.So-called positive transfer efficient be the transmission efficiency from worm screw side direction worm gear side, and counter-rotating efficient is the reciprocal transmission efficiency from worm gear side direction worm screw side.

Positive transfer efficient η 1:

[formula 1]

$\mathrm{\η}1=\frac{\cos \mathrm{\α}\cos \mathrm{\γ}-\mathrm{\μ}\sin \mathrm{\γ}}{\cos \mathrm{\α}\sin \mathrm{\γ}+\mathrm{\μ}\cos \mathrm{\γ}}\tan \mathrm{\γ}$

Counter-rotating efficiency eta 2:

[formula 2]

$\mathrm{\η}2=\frac{\cos \mathrm{\α}\sin \mathrm{\γ}+\mathrm{\μ}\cos \mathrm{\γ}}{\cos \mathrm{\α}\cos \mathrm{\γ}+\mathrm{\μ}\sin \mathrm{\γ}}\frac{1}{\tan \mathrm{\γ}}$

Wherein, α: pressure angle, γ: spiral lead angle, μ: coefficient of friction.

Fig. 3 is to be that set fixed value, transverse axis is that coefficientoffriction, the longitudinal axis are the curve chart of efficiency eta according to the spiral lead angle γ that above-mentioned formula is drawn.As an example, pressure angle α=20 ° in this curve chart.Even also present the identical trend that is close to when pressure angle is 14.5 °.

By this curve chart as can be known, there are differences between positive transfer efficient and the counter-rotating efficient.With respect to high more good more positive transfer efficient, counter-rotating efficient is in the zone of bearing 0% below, thereby can guarantee degeneration-resistant commentaries on classics (self-locking).Make worm screw and adopt polyacetals to form by roll extrusion, the combination of these two makes coefficientoffriction near 0.06.By curve chart as can be known, be between 3 ° 00 ' to 3 ° 30 ' at spiral lead angle (torsion angle), efficiency eta 2 is in the negative zone below 0%.That is to say,, can guarantee degeneration-resistant commentaries on classics by combinations thereof.And from curve chart as can be known, the positive transfer efficient of this moment can reach well-content degree.

The occasion of the polyacetals a little less than worm gear material working strength by strengthening the worm screw external diameter, increasing area of contact, can be guaranteed the intensity of worm gear.Therefore, the present invention has used the main shaft and the worm screw of independent formation.Like this, can increase the choice of the specification of tooth, do the external diameter of worm screw bigger.Can reduce wear and be out of shape by increasing total number of teeth in engagement and strengthening area of contact, thereby can be improved useful life.

Usually, require finished product to accomplish the low and miniaturization of price, want to satisfy this requirement, motor and decelerator unit all must be selected small-sized.In general, its torque of compact motor is also correspondingly little.Therefore, must with the big decelerator unit combination of speed reducing ratio to obtain necessary torque.And for the decelerator unit, speed reducing ratio senior general causes the big thereby volume increase of worm gear external diameter.Want under the situation that suppresses the worm gear external diameter, to increase speed reducing ratio (for example speed reducing ratio is 83～99), just must reduce the modulus of tooth.Therefore, when thinking to make its price hang down with miniaturization as far as possible, the miniature motor little by the torque that price is low used in the mode of high speed rotating, and the modulus that makes the tooth of decelerator unit is 0.8～0.7 or littler, just can reach requirement.Thus, can realize miniaturization with the miniature motor integral body of decelerator.

Claims (4)

1. miniature motor with decelerator, motor part and decelerator portion are assembled into one, described decelerator portion be with the motor spindle that is connected in this motor part on the worm screw of metal manufacturing and the worm gear that is engaged be contained in the gear box and constitute, when motor spindle rotates, its rotation makes the worm gear reducer rotation via the worm screw of metal manufacturing, thereby joining output shaft is with it driven, it is characterized in that

The worm screw of above-mentioned metal manufacturing is only finished fine finishining through roll extrusion,

Above-mentioned worm gear is to use polyacetals to form as its material and to it and forms,

The spiral lead angle of worm gear pairs is in 30 minutes scope of 3 degree～3 degree.

2. the miniature motor of band decelerator as claimed in claim 1 is characterized in that, the worm screw of above-mentioned metal manufacturing is a chimeric fixedly all-in-one-piece after forming with motor spindle split ground.

3. the miniature motor of band decelerator as claimed in claim 1 is characterized in that, the worm screw of above-mentioned metal manufacturing is made by continuous roll extrusion.

4. the miniature motor of band decelerator as claimed in claim 1 is characterized in that, the modulus of tooth is 0.5～0.7.

Images