JPH0244651B2 - - Google Patents
Info
- Publication number
- JPH0244651B2 JPH0244651B2 JP60202583A JP20258385A JPH0244651B2 JP H0244651 B2 JPH0244651 B2 JP H0244651B2 JP 60202583 A JP60202583 A JP 60202583A JP 20258385 A JP20258385 A JP 20258385A JP H0244651 B2 JPH0244651 B2 JP H0244651B2
- Authority
- JP
- Japan
- Prior art keywords
- driving
- jig
- assembled
- insertion hole
- assembly
- 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 - Lifetime
Links
- 238000003780 insertion Methods 0.000 claims description 38
- 230000037431 insertion Effects 0.000 claims description 38
- 238000000034 method Methods 0.000 claims description 15
- 230000000630 rising effect Effects 0.000 claims description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 238000003754 machining Methods 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、自動組付におけるシヤフト、ピン等
の組付部品を打込み治具の打込み線上に移動し、
該打込み治具により当該組付部品を被組付部品の
被挿入孔に打込むときの組付部品と被組付部品の
被挿入孔との芯合せ方法に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for moving assembly parts such as shafts and pins onto the driving line of a driving jig in automatic assembly,
The present invention relates to a method for aligning an assembly part and an insertion hole of an assembled part when driving the assembly part into an insertion hole of an assembled part using the driving jig.
第４図は従来の芯合せ方法に用いる装置の断面
図を示す。該装置の構成を説明する。図におい
て、１は打込み治具で、該打込み治具１は棒状の
打込み部２と該打込み部２を駆動する打込みシリ
ンダ３とから構成されている。４は当該装置の本
体を示す。打込み部２の下方に被組付部品５が位
置決めされて保持されている。その位置決めは、
ラフガイド６により前記打込み治具１の打込み線
方向（同図の上下方向）と直交方向（同図の水平
方向）に少し移動自在に仮保持されて組付パレツ
ト７上に載置され、且つ該パレツト７に植立され
た位置決めノツク８，８を被組付部品５に設けた
ノツク挿入孔９に挿入することにより行なわれて
いる。
FIG. 4 shows a cross-sectional view of an apparatus used in a conventional alignment method. The configuration of this device will be explained. In the figure, reference numeral 1 denotes a driving jig, and the driving jig 1 is composed of a rod-shaped driving part 2 and a driving cylinder 3 that drives the driving part 2. 4 indicates the main body of the device. A part to be assembled 5 is positioned and held below the driving part 2. Its positioning is
The driving jig 1 is temporarily held by the rough guide 6 so as to be slightly movable in the driving line direction (vertical direction in the figure) and orthogonal direction (horizontal direction in the figure), and is placed on the assembly pallet 7. This is done by inserting the positioning notches 8, 8 set up on the pallet 7 into the notch insertion holes 9 provided in the parts 5 to be assembled.
１０はシヤツター治具で、該シヤツター治具１
０はシユート用チユーブ１１から送られてくるシ
ヤフト等の組付部品１３を一個ずつ受け、これを
前記打込み治具１の打込み線上に移動するもので
ある。１４はシヤツター治具１０を往復動するシ
リンダーである。また、１５はガイドブシユで、
該ガイドブシユ１５は前記打込み線と軸芯を一致
させて本体４に取り付けられており、前記シヤツ
ター治具１０に保持されている組付部品１３の非
組付部品５の被挿入孔１６への挿入をガイドする
ものである。 10 is a shutter jig, and the shutter jig 1
0 receives assembly parts 13 such as shafts sent from the chute tube 11 one by one and moves them onto the driving line of the driving jig 1. 14 is a cylinder that reciprocates the shutter jig 10. Also, 15 is a guide bush,
The guide bush 15 is attached to the main body 4 with its axis aligned with the driving line, and the guide bush 15 is inserted into the insertion hole 16 of the unassembled component 5 of the assembled component 13 held in the shutter jig 10. It is a guide.
次に、上記装置の使用方法を説明する。先ず、
位置決めノツク８，８がノツク挿入孔９に挿入す
るように被組付部品５を組付パレツト７上に載置
保持する。これにより、前記位置決めノツク８，
８が、当該被組付部品５の被挿入孔１６が打込み
治具１の打込み線上に位置するように予め形成さ
れているため、組付部品１３と被組付部品５の被
挿入孔１６との芯合せが完了する。この後、シリ
ンー４によりシヤツター治具１０を往復させて組
付部品１３を前記打込み線上に位置させ、打込み
シリンダ３により打込み部２を下動させ、前記シ
ヤツター治具１０に保持されている組付部品１３
を被組付部品５の被挿入孔１６に押し込んで組み
付ける。 Next, how to use the above device will be explained. First of all,
The part to be assembled 5 is placed and held on the assembly pallet 7 so that the positioning notches 8, 8 are inserted into the notch insertion holes 9. As a result, the positioning notches 8,
8 is formed in advance so that the insertion hole 16 of the part to be assembled 5 is located on the driving line of the driving jig 1, so that the insertion hole 16 of the part to be assembled 13 and the part to be assembled 5 are alignment is completed. Thereafter, the shutter jig 10 is reciprocated by the cylinder 4 to position the assembly part 13 on the driving line, and the driving cylinder 3 moves the driving part 2 downward, and the assembly held in the shutter jig 10 is moved back and forth by the cylinder 4. Part 13
is pushed into the insertion hole 16 of the part to be assembled 5 and assembled.
ところで、従来の芯合せ方法は、被組付部品５
に予めノツク挿入孔９，９を穿設し、更に組付パ
レツト７に位置決めノツク８，８を設けておかな
ければならないため、被組付部品５に余分な加工
が必要となると共に、組付パレツト７の構造も複
雑化し、更にコストアツプの原因ともなつてい
た。
By the way, in the conventional alignment method, the parts to be assembled 5
Since the notch insertion holes 9, 9 must be drilled in advance in the assembly pallet 7, and the positioning notches 8, 8 must be provided in the assembly pallet 7, extra machining is required on the parts 5 to be assembled, and the assembly The structure of the pallet 7 also became complicated, which further increased costs.
本発明の目的は、被組付部品にノツク挿入孔９
といつた余分な加工をすることなく、また組付パ
レツト７に位置決めノツク８形成することなく、
芯合せをすることのできる組付部品と被組付部品
の被挿入孔との芯合せ方法を提供せんとするもの
である。 An object of the present invention is to provide a notch insertion hole 9 in a part to be assembled.
without the need for extra processing such as, and without forming positioning notches 8 on the assembly pallet 7.
It is an object of the present invention to provide a method for aligning an assembly part and an insertion hole of an assembled part, which can be aligned.
本発明は、上昇端位置と下降端位置間で上下動
する打込み治具の打込み線上に移動治具によつて
組付部品を移動し、該打込み治具により当該組付
部品を被組付部品の被挿入孔に打込みときの組付
部品と被組付部品の被挿入孔との芯合せ方法にお
いて、前記被組付部品をラフガイドによりその被
挿入孔の孔芯線と前記打込み線とを略一致させ且
つ前記打込み線と直交方向に移動可能に仮保持
し、先ず前記打込み治具を下降端位置まで下動さ
せて被組付部品の被挿入孔に前記組付部品が無い
状態で挿入した後、上昇端位置まで上動させる挿
脱操作をして芯合せし、次いで前記移動治具によ
り組付部品を打込み治具の打込み線上に移動し、
再び打込み治具を下動させて当該組付部品を被組
付部品の被挿入孔に打込むと共に、打込み治具に
形成されている段部を前記移動治具の上面に当接
させて該打込み治具を前記下降端位置の手前でそ
の下動を停止させることによつて前記組付部品の
打込み位置を規制するものである。すなわち、被
組付部品をラフガイドにより打込み治具の打込み
線と直交方向に移動自在に仮保持し、先ず打込み
治具を被組付部品の被挿入孔に挿入離脱して芯合
せをした後、組付部品を打込み治具の打込み線上
に移動し、該打込み治具により当該組付部品を被
組付部品の被挿入孔に打ち込むようにしたもので
ある。
The present invention uses a moving jig to move an assembly part onto a driving line of a driving jig that moves up and down between a rising end position and a lowering end position, and the driving jig moves the assembly part to a part to be assembled. In the method of aligning the part to be assembled and the insertion hole of the part to be assembled when driving the part into the hole to be inserted, the part to be assembled is roughly aligned with the hole core line of the hole to be inserted and the driving line by a rough guide. The driving jig was temporarily held so as to be aligned and movable in a direction orthogonal to the driving line, and the driving jig was first moved down to the lower end position and inserted into the insertion hole of the part to be assembled without the part to be assembled. After that, perform an insertion/removal operation to move it upward to the rising end position for centering, and then move the assembly part to the driving line of the driving jig using the moving jig,
Move the driving jig downward again to drive the assembly part into the insertion hole of the part to be assembled, and bring the stepped part formed on the driving jig into contact with the upper surface of the moving jig so as to The driving position of the assembly component is regulated by stopping the downward movement of the driving jig before the lowering end position. In other words, the part to be assembled is temporarily held by a rough guide so that it can move freely in the direction perpendicular to the driving line of the driving jig, and the driving jig is first inserted into and removed from the insertion hole of the part to be assembled, and then aligned. The part to be assembled is moved onto the driving line of the driving jig, and the part to be assembled is driven into the insertion hole of the part to be assembled by the driving jig.
この方法により、打込み治具の１回目の駆動に
より、被組付部品の被挿入孔を、打込み線上に位
置させるように芯合せをし、２回目の駆動により
組付部品を被挿入孔に打込んで組み付けると共
に、打込み治具の段部を移動治具の上面に当接さ
せてその下動を下降端位置手前の一定位置で停止
させることにより、打込み治具の被挿入孔内への
打込み深さを一定に規制できるようにしたもので
ある。 With this method, the first drive of the driving jig aligns the inserted hole of the part to be assembled so that it is located on the driving line, and the second drive drives the part to be assembled into the inserted hole. At the same time, the stepped part of the driving jig is brought into contact with the top surface of the movable jig and its downward movement is stopped at a certain position before the lowering end position, so that the driving jig can be driven into the inserted hole. This allows the depth to be regulated at a constant level.
第１図は本発明の芯合せ方法に用いる装置を示
す断面図である。第４図に示した従来の装置と略
同様の構成であり、次の点が構造的に単純化され
ている。すなわち、従来の位置決めノツク８及び
ノツク挿入孔９が設けられていない。その他は従
来の構成をそのまま利用できるものである。
FIG. 1 is a sectional view showing an apparatus used in the alignment method of the present invention. The configuration is substantially the same as that of the conventional device shown in FIG. 4, and the following points are structurally simplified. That is, the conventional positioning notch 8 and notch insertion hole 9 are not provided. For the rest, the conventional configuration can be used as is.
被組付部品５は、組付パレツト上に載置され、
ラフガイド６に離間して囲われ、打込み治具１の
打込み線と直交方向に少し移動自在にセツトされ
ている。ここで、ラフガイド６は、被組付部品５
をラフガイド６内に単におくだけで被挿入孔１６
の孔芯が前記打込み線とラフな状態ではあるが略
一致するように設けられている。そして、打込み
治具１の打込み部２先端にはテーパが形成され、
ラフな芯合せ状態において打込み部２を下動させ
たとき、前被被挿入孔１６内に入りやすいように
形成されている。 The parts to be assembled 5 are placed on the assembly pallet,
It is surrounded by a rough guide 6 and set so as to be slightly movable in a direction orthogonal to the driving line of the driving jig 1. Here, the rough guide 6 is the part to be assembled 5
Simply place it inside the rough guide 6 to insert it into the insertion hole 16.
The center of the hole is provided so that it roughly coincides with the driving line, although it is in a rough state. A taper is formed at the tip of the driving part 2 of the driving jig 1,
It is formed so that when the driving part 2 is moved downward in a rough alignment state, it can easily enter the front insertion hole 16.
次に、第２図及び第３図を参照して、本装置を
用いて本発明の芯合せ方法を説明する。先ず、シ
リンダー３により打込み治具１の打込み部２を下
動させると、ラフに芯合せされた被組付部品５の
被挿入孔１６内に先端テーパ部分が挿入し、更に
下動させると被組付部品５は打込み線と直交方向
すなわち、図の水平方向に少し移動され、当該被
組付部品５の被挿入孔１６は前記打込み線上に位
置するようになる。すなわち、被挿入孔１６の芯
合せが完了する（第２図）。この後、打込み部２
を上動させ、シヤツター用シリンダー１４により
シヤツター治具１０を往動させ、保持している組
付部品１３を打込み治具１の打込み線上に移動さ
せる。再び、シリンダー３により打込み部２を下
動させれば、組付部品１３は、既に芯合せの行な
われている被組付部品５の被挿入孔１６内に打込
まれる（第３図）。すなわち、本発明に係る芯合
せ方法は、上昇端位置と下降端位置間で上下動す
る打込み治具１の打込み線上に移動治具であるシ
ヤツター治具１０によつて組付部品１３を移動
し、該打込み治具１により当該組付部品１３を被
組付部品５の被挿入孔１６に打込みときの組付部
品と被組付部品の被挿入孔との芯合せ方法におい
て、前記被組付部品５をラフガイド６によりその
被挿入孔１６の孔芯線と前記打込み線とを略一致
させ且つ前記打込み線と直交方向に移動可能に仮
保持し、先ず前記打込み治具１を下降端位置まで
下動させて被組付部品５の被挿入孔１６に前記組
付部品１３が無い状態で挿入した後、上昇端位置
まで上動させる挿脱操作をして芯合せし、次いで
前記移動治具１０により組付部品１３を打込み治
具１の打込み線上に移動し、再び打込み治具１を
下動させて当該組付部品１３を被組付部品５の被
挿入孔１６に打込むと共に、打込み治具１に形成
されている段部１７を前記移動治具１０の上面に
当接させて該打込み治具１を前記下降端位置の手
前でその下動を停止させることによつて前記組付
部品１３の打込み位置を規制するものである。
尚、本実施例の装置では、シヤツター治具１０の
厚みｌを組付部品１３の長さと略同じに形成し、
更に打込み部２に段部１７を設けることにより、
芯合せ時（第２図）と打込み時（第３図）におけ
る打込み部２０下降端位置が調整されている。 Next, with reference to FIGS. 2 and 3, the alignment method of the present invention using this apparatus will be explained. First, when the driving part 2 of the driving jig 1 is moved downward by the cylinder 3, the tapered tip part is inserted into the insertion hole 16 of the assembled part 5, which is roughly aligned, and when it is further moved downward, the inserted part 2 is inserted. The part to be assembled 5 is moved a little in the direction perpendicular to the driving line, that is, in the horizontal direction in the figure, so that the insertion hole 16 of the part to be assembled 5 is positioned on the driving line. That is, the alignment of the insertion hole 16 is completed (FIG. 2). After this, the driving part 2
is moved upward, the shutter jig 10 is moved forward by the shutter cylinder 14, and the held assembly part 13 is moved onto the driving line of the driving jig 1. When the driving part 2 is moved downward again by the cylinder 3, the assembly part 13 is driven into the insertion hole 16 of the assembled part 5, which has already been aligned (FIG. 3). That is, in the alignment method according to the present invention, the assembly part 13 is moved by the shutter jig 10, which is a moving jig, onto the driving line of the driving jig 1, which moves up and down between the ascending end position and the descending end position. , in the method of aligning the assembly part and the insertion hole of the assembled part when driving the assembly part 13 into the insertion hole 16 of the assembled part 5 using the driving jig 1, The component 5 is temporarily held by the rough guide 6 so that the hole core line of the insertion hole 16 and the driving line are substantially aligned and movable in a direction perpendicular to the driving line, and first the driving jig 1 is moved to the lowering end position. After moving the assembly part 5 downward and inserting it into the insertion hole 16 of the assembly part 5 without the assembly part 13 therein, the moving jig is moved upward to the upper end position for alignment. 10, the assembly part 13 is moved onto the driving line of the driving jig 1, and the driving jig 1 is moved down again to drive the assembly part 13 into the insertion hole 16 of the to-be-assembled part 5. The assembly is performed by bringing the stepped portion 17 formed on the jig 1 into contact with the upper surface of the movable jig 10 and stopping the downward movement of the driving jig 1 before the lowering end position. This is for regulating the driving position of the component 13.
In the device of this embodiment, the thickness l of the shutter jig 10 is formed to be approximately the same as the length of the assembly part 13,
Furthermore, by providing the stepped portion 17 in the driving portion 2,
The lowering end position of the driving part 20 is adjusted during alignment (FIG. 2) and driving (FIG. 3).
本発明によれば、打込み治具の１回目の駆動に
より被組付部品の挿入孔を打込み線上に位置する
ように芯合せし、２回目の駆動により組付部品を
既に芯合せの行なわれている前記被挿入孔に打込
んで組み付けると共に、打込み治具の段部を移動
治具の上面に当接させてその下動を下降端位置手
前の一定位置で停止するようにしたので、被組付
部品に芯合せのための余分な加工をする必要がな
くなる。同様に組付けパレツトにも芯合せ用の余
分な加工をする必要がなくなり、芯合せ作業を単
純化することができる。更に組付部品を被組付部
品の被挿入孔内に一定の深さで組み付けることが
できる。
According to the present invention, the first driving of the driving jig aligns the insertion hole of the part to be assembled so that it is located on the driving line, and the second driving aligns the part to be assembled so that it is located on the driving line. At the same time, the stepped part of the driving jig is brought into contact with the top surface of the moving jig and its downward movement is stopped at a certain position before the lowering end position, so that the assembled There is no need to perform extra processing for alignment on attached parts. Similarly, there is no need to perform extra machining for alignment on the assembled pallet, and the alignment work can be simplified. Furthermore, the part to be assembled can be assembled into the insertion hole of the part to be assembled at a constant depth.
第１図は、本発明の芯合せ方法に用いる装置を
示す断面図、第２図は同装置の芯合せ時を示す要
部断面図、第３図は同装置の打込み時を示すを要
部断面図であり、第４図は従来の芯合せ方法に用
いる装置の断面図を示す。
１…打込み治具、３…組付部品、５…被組付部
品、６…ラフガイド、１６被挿入孔。
FIG. 1 is a sectional view showing the device used in the alignment method of the present invention, FIG. 2 is a sectional view of the main part of the device during alignment, and FIG. 3 is a sectional view of the main part of the device during driving. FIG. 4 shows a cross-sectional view of an apparatus used in a conventional alignment method. DESCRIPTION OF SYMBOLS 1... Driving jig, 3... Parts to be assembled, 5... Parts to be assembled, 6... Rough guide, 16 Inserted hole.
Claims (1)
み治具の打込み線上に移動治具によつて組付部品
を移動し、該打込み治具により当該組付部品を被
組付部品の被挿入孔に打込みときの組付部品と被
組付部品の被挿入孔との芯合せ方法において、 前記被組付部品をラフガイドによりその被挿入
孔の孔芯線と前記打込み線とを略一致させ且つ前
記打込み線と直交方向に移動可能に仮保持し、先
ず前記打込み治具を下降端位置まで下動させて被
組付部品の被挿入孔に前記組付部品が無い状態で
挿入した後、上昇端位置まで上動させる挿脱操作
をして芯合せし、次いで前記移動治具により組付
部品を打込み治具の打込み線上に移動し、再び打
込み治具を下動させて当該組付部品を被組付部品
の被挿入孔に打込むと共に、打込み治具に形成さ
れている段部を前記移動治具の上面に当接させて
該打込み治具を前記下降端位置の手前でその下動
を停止させることによつて前記組付部品の打込み
位置を規制することを特徴とする組付部品と被組
付部品の被挿入孔との芯合せ方法。[Scope of Claims] 1. A moving jig moves an assembled part onto a driving line of a driving jig that moves up and down between a rising end position and a lowering end position, and the driving jig covers the assembled part. In the method of aligning the assembly part with the insertion hole of the assembly part when driving into the insertion hole of the assembly part, the assembly part is aligned with the hole center line of the insertion hole and the driving line by a rough guide. The driving jig is temporarily held so as to be substantially coincident with the driving line and movable in a direction perpendicular to the driving line, and the driving jig is first moved down to the lowering end position so that there is no part to be assembled in the insertion hole of the part to be assembled. After inserting it, perform an insertion/removal operation to move it up to the upper end position to align the centering, then use the moving jig to move the assembled part onto the driving line of the driving jig, and move the driving jig down again. drive the assembly part into the insertion hole of the part to be assembled, and bring the step formed in the driving jig into contact with the top surface of the moving jig to move the driving jig to the lower end position. A method for aligning an assembly part and an insertion hole of an assembled part, characterized in that the driving position of the assembly part is restricted by stopping the downward movement before the assembly part.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20258385A JPS6263028A (en) | 1985-09-13 | 1985-09-13 | Method for alignment between assembling parts and inserted hole of assembled parts |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20258385A JPS6263028A (en) | 1985-09-13 | 1985-09-13 | Method for alignment between assembling parts and inserted hole of assembled parts |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6263028A JPS6263028A (en) | 1987-03-19 |
| JPH0244651B2 true JPH0244651B2 (en) | 1990-10-04 |
Family
ID=16459887
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20258385A Granted JPS6263028A (en) | 1985-09-13 | 1985-09-13 | Method for alignment between assembling parts and inserted hole of assembled parts |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6263028A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5555152B2 (en) * | 2010-12-24 | 2014-07-23 | ヤマハ発動機株式会社 | Parts press-fitting device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59129631A (en) * | 1983-01-14 | 1984-07-26 | Mitsubishi Motors Corp | Apparatus for attaching oil seal cap of transmission |
-
1985
- 1985-09-13 JP JP20258385A patent/JPS6263028A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59129631A (en) * | 1983-01-14 | 1984-07-26 | Mitsubishi Motors Corp | Apparatus for attaching oil seal cap of transmission |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6263028A (en) | 1987-03-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3973863A (en) | Drill changing device | |
| JPH0244651B2 (en) | ||
| WO2000023222A1 (en) | Method and device for replacing pipe electrode for small-hole electric discharge machining and electrode magazine | |
| JPH06226557A (en) | Inserting method for axial parts | |
| CN111546039B (en) | Method for completing press mounting of multiple bearings by one-time clamping | |
| JPS64165B2 (en) | ||
| CN112025255A (en) | Method for pressing bearings at two ends of rotor | |
| JP3070312B2 (en) | Jig for press-fitting crank pin | |
| JP3034320B2 (en) | Automatic piston assembly device | |
| JPH05329721A (en) | Assembling method and assembling device for needle roller | |
| CN212682531U (en) | Drill jig | |
| CN217493522U (en) | Clamping device of rocker arm machining center | |
| JPS61274833A (en) | Automatic tool changer | |
| CN217647520U (en) | Be used for rocking arm processing equipment | |
| JP2999984B2 (en) | Pin driving device | |
| JPH0453878Y2 (en) | ||
| JP3918591B2 (en) | Optical fiber insertion device | |
| JPH0414908Y2 (en) | ||
| JPH0324247Y2 (en) | ||
| JPH01141059A (en) | Wire pass through jig | |
| JPS606312A (en) | Insertion of needle into workpiece having dummy shaft | |
| JPS6250022A (en) | Method and device for positioning in sheet metal work line | |
| CN111463009A (en) | Material transferring type winding machine | |
| JPS6377613A (en) | Parts feeding mechanism | |
| JPS5943815A (en) | Groove indexing device cylindrical parts having grooves on inside circumference |