JP2509352Y2 - Self-aligning ball bearings - Google Patents

Self-aligning ball bearings

Info

Publication number
JP2509352Y2
JP2509352Y2 JP1989139016U JP13901689U JP2509352Y2 JP 2509352 Y2 JP2509352 Y2 JP 2509352Y2 JP 1989139016 U JP1989139016 U JP 1989139016U JP 13901689 U JP13901689 U JP 13901689U JP 2509352 Y2 JP2509352 Y2 JP 2509352Y2
Authority
JP
Japan
Prior art keywords
cage
ball
pocket
balls
outer ring
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP1989139016U
Other languages
Japanese (ja)
Other versions
JPH0377813U (en
Inventor
隆俊 飯谷
兆 丸山
圭三 小林
Original Assignee
エヌティエヌ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by エヌティエヌ株式会社 filed Critical エヌティエヌ株式会社
Priority to JP1989139016U priority Critical patent/JP2509352Y2/en
Publication of JPH0377813U publication Critical patent/JPH0377813U/ja
Application granted granted Critical
Publication of JP2509352Y2 publication Critical patent/JP2509352Y2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C23/00—Bearings for exclusively rotary movement adjustable for aligning or positioning
    • F16C23/06—Ball or roller bearings
    • F16C23/08—Ball or roller bearings self-adjusting
    • F16C23/082—Ball or roller bearings self-adjusting by means of at least one substantially spherical surface
    • F16C23/086—Ball or roller bearings self-adjusting by means of at least one substantially spherical surface forming a track for rolling elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
    • F16C19/14—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load
    • F16C19/18—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls
    • F16C19/181—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls with angular contact
    • F16C19/183—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls with angular contact with two rows at opposite angles

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Support Of The Bearing (AREA)

Description

【考案の詳細な説明】 〔産業上の利用分野〕 この考案は、自動調心玉軸受に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a self-aligning ball bearing.

〔従来の技術〕[Conventional technology]

上記自動調心玉軸受は、第３図に示すように、外輪１
の球状内面２と内輪３の外周に形成した複列のボール溝
４間に複数のボール５を組込み、そのボール５を保持器
６で保持した構成とされている。The self-aligning ball bearing, as shown in FIG.
A plurality of balls 5 are built in between the spherical inner surface 2 and a plurality of rows of ball grooves 4 formed on the outer periphery of the inner ring 3, and the balls 5 are held by a cage 6.

ここで、保持器６には、金属板をプレス成形したもの
や合成樹脂で成形したものがあり、合成樹脂より成る保
持器６はボール５を収容するポケット７を無理抜きによ
って成形する必要があるため、上記ポケット７は保持器
６の側面で開口する構成とされている。このため、保持
器６の幅寸法Ｗは、複列のボール５中心間の距離ａより
大きく、ボール５の外接平面間の寸法ｂより小さくなっ
ている。Here, the retainer 6 includes a press-formed metal plate and a synthetic resin, and the retainer 6 made of synthetic resin needs to have a pocket 7 for accommodating the balls 5 formed by force. Therefore, the pocket 7 is configured to open on the side surface of the cage 6. Therefore, the width dimension W of the cage 6 is larger than the distance a between the centers of the balls 5 in the double row and smaller than the dimension b between the circumscribing planes of the balls 5.

このような合成樹脂性保持器６を有する自動調心玉軸
受の組立ては、第４図に示すように、内輪３、ボール５
および保持器６を先に組み立てると共にポケット７の１
つは空とし、その組立品Ａの中心軸（イ）と外輪１の中
心軸（ロ）とを交差させ、空のポケット７を側部に位置
させた状態で外輪１の内側に組立品Ａを挿入する（第５
図参照）。次に組立品Ａを中心軸（イ）を中心に回動し
て第６図に示すように、空のポケット７を外輪１の外側
に位置させ、そのポケット７内にボール５を組込んだの
ち、外輪１の中心軸（ロ）に対して交差する直線（ハ）
を中心に組立品Ａを90°回転させ、組立品Ａの中心軸
（イ）と外輪１の中心軸（ロ）を一致させる。As shown in FIG. 4, the self-aligning ball bearing having the synthetic resin cage 6 is assembled with the inner ring 3 and the ball 5 as shown in FIG.
And retainer 6 are first assembled and pocket 7 is
One is empty, the central axis (a) of the assembly A and the central axis (b) of the outer ring 1 are crossed, and the assembly A is placed inside the outer ring 1 with the empty pocket 7 positioned on the side. Insert (5th
See figure). Next, the assembly A is rotated around the central axis (a) so that the empty pocket 7 is positioned outside the outer ring 1 and the ball 5 is incorporated into the pocket 7 as shown in FIG. Later, a straight line (C) that intersects the central axis (B) of the outer ring 1
The assembly A is rotated by 90 ° around, and the central axis (a) of the assembly A and the central axis (b) of the outer ring 1 are aligned.

自動調心玉軸受は上記のように、組立品Ａの中心軸
（イ）を外輪１の中心軸（ロ）に交差させた状態で外輪
１の内側に組立品Ａを挿入するため、第３図の鎖線で示
した外輪１の入口円（ニ）より外側に保持器６の一部が
突出していると、外輪１の内側に組立品Ａを挿入すると
き保持器６が外輪１の入口８に干渉し、外輪１の内側に
組立品Ａを挿入することができない。As described above, the self-aligning ball bearing inserts the assembly A inside the outer ring 1 with the center axis (a) of the assembly A intersecting the center axis (b) of the outer ring 1. When a part of the cage 6 projects outside the inlet circle (d) of the outer ring 1 shown by the chain line in the figure, when the assembly A is inserted inside the outer ring 1, the cage 6 receives the inlet 8 of the outer ring 1. Therefore, the assembly A cannot be inserted inside the outer ring 1.

そこで、保持器６は、上記入口円（ニ）内に納まる大
きさとされている。このため、ボール５のピッチ円上に
位置するポケット７の中心01から保持器６の円筒状外面
９までの保持器半径方向の厚みt1は、ボール溝４の溝深
さｈに略等しい大きさとされている。Therefore, the cage 6 is sized to fit within the entrance circle (d). Therefore, the thickness t 1 in the cage radial direction from the center 0 1 of the pocket 7 located on the pitch circle of the ball 5 to the cylindrical outer surface 9 of the cage 6 is substantially equal to the groove depth h of the ball groove 4. It is supposed to be large.

〔考案が解決しようとする課題〕[Problems to be solved by the device]

上記のように、従来の合成樹脂性保持器６は、ポケッ
ト中心01から保持器６の円筒状外面９までの保持器半径
方向の厚みt1がボール溝４の深さｈに略等しい大きさで
あるため、保持器６のポケット７内にボール５を組込
み、その保持器６を内輪３の外側に嵌め合わせようとす
ると、ボール５がポケット７から脱落する。As described above, in the conventional synthetic resin cage 6, the thickness t 1 in the cage radial direction from the pocket center 0 1 to the cylindrical outer surface 9 of the cage 6 is substantially equal to the depth h of the ball groove 4. Therefore, when the ball 5 is incorporated into the pocket 7 of the cage 6 and the cage 6 is fitted to the outside of the inner ring 3, the ball 5 falls out of the pocket 7.

このため、内輪３の外側に保持器６を嵌め合わせてか
ら保持器６の外径側よりポケット７内にボール５を組み
込む必要が生じる。したがって、これらの組立ては手作
業の組立てになり、組立ての自動化を行なうことができ
なかった。Therefore, it is necessary to fit the cage 6 to the outer side of the inner ring 3 and then incorporate the balls 5 into the pocket 7 from the outer diameter side of the cage 6. Therefore, the assembling of these is a manual assembling, and the assembling cannot be automated.

そこで、この考案は上記の不都合を解消し、ポケット
内にボールをはめ込んだ状態で保持器を内輪の外側に嵌
め合わせることができるようにして組立ての自動化を行
なうことができるようにした自動調心玉軸受を提供する
ことを技術的課題としている。Therefore, this invention solves the above-mentioned inconvenience, and enables the assembly to be automated by allowing the retainer to be fitted to the outside of the inner ring with the ball fitted in the pocket. The technical challenge is to provide ball bearings.

〔課題を解決するための手段〕[Means for solving the problem]

上記の課題を解決するために、この考案においては、
外輪の球状内面と内輪の外周に形成された複列のボール
溝間に多数のボールを組込み、そのボールを合成樹脂か
ら成る円筒形保持器で保持し、その保持器に形成された
ボール収納用ポケットが保持器の側面で開口する自動調
心玉軸受において、前記ボールのピッチ円上に位置する
ポケットの中心から保持器の円筒状外面までの保持器半
径方向の厚みをボール溝の溝深さより大きくし、保持器
の円筒状外面の両端部にぬすみを設け、そのぬすみが軸
受中心上に描かれる外輪両端の入口円より内側に位置さ
せた構成を採用している。In order to solve the above problems, in this invention,
A large number of balls are installed between the double-row ball grooves formed on the spherical inner surface of the outer ring and the outer circumference of the inner ring, and the balls are held by a cylindrical retainer made of synthetic resin, and the balls are stored in the retainer. In a self-aligning ball bearing in which the pocket opens on the side surface of the cage, the thickness in the cage radial direction from the center of the pocket located on the pitch circle of the ball to the cylindrical outer surface of the cage is determined from the groove depth of the ball groove. The cage is made larger and has a hollow at both ends of the cylindrical outer surface of the cage, and the hollow is located inside the inlet circles at both ends of the outer ring drawn on the center of the bearing.

ここで、ぬすみは、保持器の円筒状外面の両端面にテ
ーパ面を形成した構成とし、あるいは丸みをつけた構成
としてもよい。Here, the slime may have a configuration in which tapered surfaces are formed on both end surfaces of the cylindrical outer surface of the cage, or may be rounded.

〔作用〕[Action]

内輪、保持器およびボールの組み立てに際しては、保
持器のポケットにボールをはめ込んで保持器とボールを
先に組み立てたのち、上記保持器を内輪の外側にはめ合
わせる。その際、内輪の外径面上をボールが乗り越える
とき、ボールはボール溝の深さに対する距離だけ保持器
の外径方向に移動するが、ボールのピッチ円上に位置す
るポケット中心から保持器の円筒状外面までの保持器半
径方向の厚みは上記ボールの移動量より大きいため、ポ
ケットからボールが脱落するのを防止することができ
る。When assembling the inner ring, the cage and the balls, the balls are fitted into the pockets of the cage, the cage and the balls are assembled first, and then the cage is fitted to the outside of the inner ring. At that time, when the ball rides on the outer diameter surface of the inner ring, the ball moves in the outer diameter direction of the cage by a distance with respect to the depth of the ball groove, but from the center of the pocket located on the pitch circle of the ball of the cage. Since the thickness of the retainer in the radial direction up to the cylindrical outer surface is larger than the amount of movement of the ball, it is possible to prevent the ball from falling out of the pocket.

〔実施例〕〔Example〕

以下、この考案の実施例を第１図および第２図に基づ
いて説明する。なお、先に述べた第３図の部品と同一の
ものは同一符号を付して説明を省略する。An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The same parts as those in FIG. 3 described above are designated by the same reference numerals, and the description thereof will be omitted.

図示のように、保持器６は円筒状外面９を有し、その
外面９からボール５のピッチ円上に位置するポケット７
の中心01までの保持器半径方向の厚みt2は、内輪３に形
成されたボール溝４の深さｈより大きくなっている。As shown, the retainer 6 has a cylindrical outer surface 9 from which the pocket 7 located on the pitch circle of the ball 5.
The thickness t 2 of the cage in the radial direction of the cage up to the center 0 1 thereof is larger than the depth h of the ball groove 4 formed in the inner ring 3.

また、保持器６の円筒状外面９の両端部にはぬすみ10
が設けられている。ここで、ぬすみ10は、円筒状外面９
の両端部にテーパ面を形成した構成であってもよく、あ
るいは丸みをつけた構成であってもよい。このぬすみ10
は、軸受の中心上に描かれる外輪１両端の入口円（ニ）
より内側に配置されている。Also, there is a slack 10 on both ends of the cylindrical outer surface 9 of the cage 6.
Is provided. Here, the slime 10 is the cylindrical outer surface 9
It may have a structure in which tapered surfaces are formed at both ends of, or may have a rounded structure. This slime 10
Is the inlet circle (d) at both ends of the outer ring 1 drawn on the center of the bearing
It is located inside.

上記のように、ボール５のピッチ円上に位置するポケ
ット中心01から保持器６の円筒状外面９までの保持器半
径方向の厚みt2をボール溝４の深さｈより大きくしたこ
とにより、ポケット７内にボール５を組込んだ状態で保
持器６を内輪３に組込むことができる。すなわち、各ポ
ケット７内にボール５をはめ込み、ボール５と保持器６
の組立て品を内輪３の外側にはめ合わせると、ボール５
は内輪３の外径面を乗り越えるとき、第２図に示すよう
にボール溝４の深さｈに対応する距離だけボール５は外
径方向に移動するが、ポケット中心01から内筒状外面９
までの保持器半径方向の厚みt2が上記ボール５の移動量
より大きいため、ポケット７からボール５が脱落せず、
内輪３の外側に保持器６とボール５の組立て品を確実に
組込むことができる。As described above, the thickness t 2 in the cage radial direction from the pocket center 0 1 located on the pitch circle of the ball 5 to the cylindrical outer surface 9 of the cage 6 is made larger than the depth h of the ball groove 4. The cage 6 can be assembled to the inner ring 3 with the ball 5 assembled in the pocket 7. That is, the ball 5 is fitted into each pocket 7 and the ball 5 and the cage 6 are
When the assembly of is fitted to the outside of the inner ring 3, the ball 5
When moving over the outer diameter surface of the inner ring 3, the ball 5 moves in the outer diameter direction by a distance corresponding to the depth h of the ball groove 4 as shown in FIG. 2, but from the pocket center 0 1 to the inner cylindrical outer surface. 9
Since the thickness t 2 in the radial direction of the cage up to is larger than the movement amount of the ball 5, the ball 5 does not drop from the pocket 7,
The assembly of the retainer 6 and the ball 5 can be reliably incorporated into the outer side of the inner ring 3.

上記のようにして組立てた内輪３、ボール５および保
持器６の組立て品を外輪１の内側に組込むには、ポケッ
ト７の１つを空としておき、第４図および第６図に示す
順序に従って組み込むようにする。To assemble the assembly of the inner ring 3, the ball 5 and the cage 6 assembled as described above into the inner side of the outer ring 1, leave one of the pockets 7 empty and follow the order shown in FIGS. 4 and 6. Try to include it.

その組立てにおいて、保持器６の円筒状外面９の両端
部には、ぬすみ10が設けられているため、ポケット７の
１つを空とした保持器６を外輪１の内側に挿入する際、
保持器６が外輪１の両端の入口８に干渉せず、外輪１の
内側に保持器６を確実に組込むことができる。In the assembly, since the hollows 10 are provided at both ends of the cylindrical outer surface 9 of the cage 6, when inserting the cage 6 with one of the pockets 7 empty into the outer ring 1,
The cage 6 does not interfere with the inlets 8 at both ends of the outer ring 1, and the cage 6 can be reliably incorporated inside the outer ring 1.

〔考案の効果〕[Effect of device]

以上のように、この考案に係る自動調心玉軸受におい
ては、ボールのピッチ円上に位置するポケットの中心か
ら保持器の円筒状外面までの保持器半径方向の厚みをボ
ール溝の深さより大きくしたので、ポケット内にボール
を組込んだ保持器を内輪の外側に嵌め合わせることがで
きる。As described above, in the self-aligning ball bearing according to the present invention, the radial thickness of the cage from the center of the pocket located on the pitch circle of the ball to the cylindrical outer surface of the cage is made larger than the depth of the ball groove. Therefore, the cage having the balls incorporated in the pocket can be fitted to the outer side of the inner ring.

このため、内輪、ボールおよび保持器の組立ての自動
化を図ることができ、組立て作業の能率向上に大きな効
果を挙けることができる。Therefore, the assembly of the inner ring, the balls, and the cage can be automated, and the efficiency of the assembly work can be greatly improved.

また、保持器の円筒状外面の両端部にぬすみを形成し
てあるため、保持器を外輪の内側に組込む際に、保持器
が外輪の入口に干渉するのを防止することができ、内
輪、ボールおよび保持器の組立て品を従来と同様の組立
てによって外輪の内側に組む込むことができる。Further, since the hollows are formed at both ends of the cylindrical outer surface of the cage, it is possible to prevent the cage from interfering with the inlet of the outer ring when the cage is assembled inside the outer ring, The ball and cage assembly can be incorporated inside the outer ring by conventional assembly.

【図面の簡単な説明】[Brief description of drawings]

第１図は、この考案に係る自動調心玉軸受の一実施例を
示す断面図、第２図は内輪に保持器を組立てる際の途中
の状態を示す断面図、第３図は従来の自動調心玉軸受の
断面図、第４図乃至第６図は上記玉軸受の組立てを段階
的に示す斜視図である。 １……外輪、２……球状内面、３……内輪、４……ボー
ル溝、５……ボール、６……保持器、７……ポケット、
９……円筒状外面、10……ぬすみ、（ニ）……入口円。FIG. 1 is a sectional view showing an embodiment of a self-aligning ball bearing according to the present invention, FIG. 2 is a sectional view showing an intermediate state of assembling a cage to an inner ring, and FIG. 3 is a conventional automatic bearing. Sectional views of the centering ball bearing, and FIGS. 4 to 6 are perspective views showing the assembly of the ball bearing in stages. 1 ... Outer ring, 2 ... Spherical inner surface, 3 ... Inner ring, 4 ... Ball groove, 5 ... Ball, 6 ... Retainer, 7 ... Pocket,
9 ... Cylindrical outer surface, 10 ... Null, (D) ... Entrance circle.

Claims (1)

(57)【実用新案登録請求の範囲】(57) [Scope of utility model registration request] 【請求項１】外輪の球状内面と内輪の外周に形成された
複列のボール溝間に多数のボールを組込み、そのボール
を合成樹脂から成る円筒形保持器で保持し、その保持器
に形成されたボール収納用ポケットが保持器の側面で開
口する自動調心玉軸受において、前記ボールのピッチ円
上に位置するポケットの中心から保持器の円筒状外面ま
での保持器半径方向の厚みをボール溝の溝深さより大き
くし、保持器の円筒状外面の両端部にぬすみを設け、そ
のぬすみが軸受中心上に描かれる外輪両端の入口円より
内側に位置されていることを特徴とする自動調心玉軸
受。1. A large number of balls are installed between a plurality of rows of ball grooves formed on the spherical inner surface of the outer ring and the outer circumference of the inner ring, and the balls are held by a cylindrical retainer made of synthetic resin and formed on the retainer. In the self-aligning ball bearing in which the formed ball storage pocket opens on the side surface of the cage, the thickness of the ball in the radial direction from the center of the pocket located on the pitch circle of the ball to the cylindrical outer surface of the cage The automatic adjustment is characterized in that the groove is deeper than the groove depth, and the cage is provided with slacks at both ends of the cylindrical outer surface, and the slacks are located inside the inlet circles at both ends of the outer ring drawn on the bearing center. Heart ball bearing.
JP1989139016U 1989-11-29 1989-11-29 Self-aligning ball bearings Expired - Fee Related JP2509352Y2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1989139016U JP2509352Y2 (en) 1989-11-29 1989-11-29 Self-aligning ball bearings

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1989139016U JP2509352Y2 (en) 1989-11-29 1989-11-29 Self-aligning ball bearings

Publications (2)

Publication Number Publication Date
JPH0377813U JPH0377813U (en) 1991-08-06
JP2509352Y2 true JP2509352Y2 (en) 1996-09-04

Family

ID=31686087

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1989139016U Expired - Fee Related JP2509352Y2 (en) 1989-11-29 1989-11-29 Self-aligning ball bearings

Country Status (1)

Country Link
JP (1) JP2509352Y2 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008016977A1 (en) * 2008-04-03 2009-10-08 Schaeffler Kg Ball roller bearing and method for mounting such a ball roller bearing
JP5636887B2 (en) * 2010-11-09 2014-12-10 日本精工株式会社 Tandem angular contact ball bearings
CN113847336A (en) * 2021-08-16 2021-12-28 人本股份有限公司 Hub bearing

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5956418U (en) * 1982-10-06 1984-04-13 日本精工株式会社 spherical roller bearing

Also Published As

Publication number Publication date
JPH0377813U (en) 1991-08-06

Similar Documents

Publication Publication Date Title
US3938866A (en) Roller cages formed from apertured separators for roller bearings
JP2535587B2 (en) Thin cross roller bearing
JPH0155808B2 (en)
US2883244A (en) Bearing devices
US7828483B2 (en) Angular contact ball bearing
JP2509352Y2 (en) Self-aligning ball bearings
JPS626532U (en)
EP0375938A1 (en) Rolling-contact bearing
US20090080825A1 (en) Angular contact ball bearing
EP0718512A1 (en) Low friction roller bearing
JP2523874Y2 (en) Angular contact ball bearings
JPS6342177Y2 (en)
JPH02122215U (en)
JP3571490B2 (en) Double row angular contact ball bearing
JPH0648181Y2 (en) Synthetic resin cage for ball bearings
JPH0227693Y2 (en)
JP2527963Y2 (en) Synthetic resin cage for ball bearings
CN217055995U (en) Cylindrical roller retainer free of spring pin fixation
JP2001214930A (en) Interval body for ball bearing
JPS6114748Y2 (en)
JP4196390B2 (en) Spherical roller bearing
JPS6222320U (en)
JPS624622U (en)
JP2543929Y2 (en) Press cage for ball bearings
JPS61150524U (en)

Legal Events

Date Code Title Description
LAPS Cancellation because of no payment of annual fees