CN2044668U

CN2044668U - Gear with circum-scribed teeth

Info

Publication number: CN2044668U
Application number: CN 89202223
Authority: CN
Inventors: 季爱国
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-03-06
Filing date: 1988-03-06
Publication date: 1989-09-20

Abstract

The utility model discloses a gear with circum-scribed teeth, belonging to a novel gear of the gear drive in the mechanical drive. The geometric structure is that a centre point on the graduation line of a graduated circle circum-scribes an excircle in the graduation line by a circle with a gear-form radius 4 as the tooth form line, ascertaining a tooth width 5, and forming the circum-scribed teeth; the gear with circum-scribed teeth is formed by the circum-scribed teeth equidistantly distributed on the graduation line. The utility model has small friction angle of the teeth, big contact face, big abrasive resistance, fine drive cooperation and almost no impact between the teeth; the pressure angle is reduced when the number of the teeth is increased, making the radial force of the gear tend to zero; the drive noise is small; the gear form is thick and difficult to undercut or beat the teeth. The application of the gear with circum-scribed teeth can effectively increase the gear drive performance and prolong the service life.

Description

Gear with circum-scribed teeth

The circumscribed gear gear is a kind of new gear of mechanical transmission middle gear transmission.

Used gear transmission, what it generally adopted is Involutes Gears Transmission: though Involutes Gears Transmission has unarguable advantage, but certain shortcoming is arranged also: the normal radius of curvature of working flank is little because the pairing tooth is line contact, to axle to misalign receptance big; By its be the frictional loss that produces greatly owing to the slip effect in the gear teeth meshing and the gear teeth impact and pressure angle big, and undercut takes place in the gear teeth easily.

The purpose of invention circumscribed gear gear is for the mechanical transmission performance and the working life of improving gear, and can effectively overcome or reduce the shortcoming in the said gear transmission.

The utility model gear is like this design: equate the outer tangent line of the mutually circumscribed circle that forms of circle line according to two radius, the gear as the gear teeth formation of flank profil is called the circumscribed gear gear.Utilize circumscribed gear thus, just can design different shape cylinder. circular cone. straight-tooth. helical teeth or herringbone tooth gear and gear ring and tooth bar.

Because circumscribed gear is knuckle-tooth shape, centre point is on the reticule of gear and be evenly distributed on certain equal radii circular arc line phase circumscribed figure exterior feature, so constitute for its how much and uncomplicated; And profile of tooth is to be meshed with circular arc line, so just caused friction angle little, and surface of contact is big, then just strengthened the wear resistance of the gear teeth, and be difficult for taking place undercut.Again because tooth top and tooth root are that circular arc is linear, no corner angle, and also setback meshes and carries out simultaneously, so fundamentally overcome gear teeth impact substantially.Particularly the pressure angle of circumscribed gear gear is that the profile of tooth radius is half of the corresponding core wheel of string angle, so relative many more of the gear teeth, its pressure angle is just more little thereupon.So like this radial force that is subjected to of gear can be littler, thereby outstanding more for the many gear transmissions of the number of teeth, demonstrates the transmission performance of the superior uniqueness of circumscribed gear gear.

The geometrical shape constituent relation of circumscribed gear gear and gear teeth meshing transmission situation are provided by following example and accompanying drawing thereof:

Fig. 1 is circumscribed gear profile of tooth figure.

Fig. 2 is the dimension name figure of circumscribed gear gear each several part.

Fig. 3 is a circumscribed gear gear engagement situation schematic representation.

Fig. 4 is the instantaneous setback engagement of a circumscribed gear gear situation schematic representation.

Fig. 5 is that the circumscribed gear gear meshes the situation schematic representation fully.＜the slightly round line arrow of Fig. 3 .4.5 is represented to turn to 〉

Wherein: 1--tip diameter 10--space width

2--standard pitch diameter 11--circular pitch

3--root diameter 12--active force

4--profile of tooth radius 13--point of action＜contact points 〉

The meshing line of 5--facewidth 14--

6--tooth depth 15--pressure angle

7--addendum 16--gear centre point

The instantaneous motion direction of 8--dedendum of the tooth 17--point of action

The 9--transverse tooth thickness

In conjunction with the accompanying drawings 1 the explanation circumscribed gear basic geometrical construction.

With size arrow 2 is that the circular arc that standard pitch diameter is drawn is a reticule, represents with dot and dash line.Centre point with the profile of tooth radius 4 reticule outer arc of drawing, then is the tooth top outer profile on reticule; And then with radius 4 at standard pitch circle line and the mutually circumscribed line in top circle profile both sides to the inboard camber line of drawing of standard pitch circle, then be the tooth root outer profile, so just formed a complete profile of tooth outer profile.There has been the flank profil line to determine the facewidth 5 again, just formed circumscribed naturally.We just are called circumscribed gear with circumscribed as the gear teeth.

The constituent relation of 2 explanation circumscribed gear gear each several part sizes in conjunction with the accompanying drawings.

Specifically Fig. 2 is circumscribed gear straight toothed spur gear figure, is not difficult to find out from figure: above-mentioned circumscribed gear, with certain number of teeth with standard pitch circle line five equilibrium, so just determined profile of tooth radius 4.The type tooth of size is equally distributed on the reticule like this, has just formed complete circumscribed gear gear.On gear, addendum 7 and dedendum of the tooth 8 all equal profile of tooth radius 4; So tooth depth 6 just equals the profile of tooth diameter, then tip diameter 1 equals standard pitch diameter 2 and adds two profile of tooth radiuses 4, and root diameter 3 then equals standard pitch diameter 2 and deducts two profile of tooth radiuses 4.Transverse tooth thickness 9 equals the distance of between cog 10, then circular pitch 11 be transverse tooth thickness and between cog apart from sum.The width of tooth is determined by the facewidth 5.

3 circumscribed gear gear engagement situations are described in conjunction with the accompanying drawings.

Among Fig. 3.Gear centre point 16 is the axle center, and the contact points 13 of two gear teeth also is the snap point of two gear teeth, is the instantaneous motion direction 17 of point of action in the tangent direction of contact points, and meshing line 14 also overlaps with the tangent line of contact points simultaneously.Thereby the centre point of the profile of tooth of engaging tooth circle then be the direction of power 12, so the angle of the direction of power and instantaneous motion direction is exactly a pressure angle 15 to contact points 13; And the profile of tooth radius as the string of standard pitch circle half of right gear central angle, just in time equal pressure angle 15.Therefore the number of teeth that gear is relative is many more, and then the profile of tooth radius is more little, so pressure angle also just reduces thereupon.

In accompanying drawing 4, carry out because the gear teeth withdraw from when entering engagement, thus snap point 13 with instantaneous two pairs meshing on since turnover engagement time be subjected to the existence of momentary force 12, just impel gear stressed continuously, so fundamentally eliminate or the impact of minimizing between cog.And the pressure angle 15 of strength of gear is constant when turnover is meshing.

Accompanying drawing 5 is equivalent to the engagement situation that the gear teeth enter six pressure angles 15 of meshing commentaries on classics, and at this moment active force 12 is along the tangent direction of driven gear contact points 13, so this instantaneous pressure angle that do not exist.

Claims

1, a kind of circumscribed gear gear, the circle mutually circumscribed connection reticule inside and outside circle line on reticule that it is characterized in that profile of tooth radius 4 is the profile of tooth profile, determined the facewidth 5, just formed circumscribed gear, equidistantly to be evenly distributed on the reticule be exactly the circumscribed gear gear to circumscribed gear thus.