201121740 六、發明說明： 【發明所屬之技術領域】 [0001] 本發明涉及一種機器人，尤其涉及一種具有依次連接之 複數手腕單元之工業機器人。 【先前技術】 [〇〇〇2]工業機器人通常具備：可繞第一轴線轉動之第一手腕單 元，該第一手腕單元之前端一側形成一叉形結構；可轉 動地設於該叉形結構之二側部間之第二手腕單元；以及 於該第二手腕單元之前端—側，可轉動設置之第三手腕 單兀。第二手腕單元作為卫業機器人之末端軸，如六軸 工業機器人之第六輛，可用於裝設失具、切削工具及探 測器等末端執行器以執行各種任務。上述第一及第三手 腕單元之旋轉轴線通常分別與第二手腕單元之旋轉轴線 I： .. ......... 正交’故’第三手腕單元及末端執行器跟隨第二手腕單 元轉動過程中易碰觸第一手腕單元，使第二手腕單元之 旋轉角度受到限制，不能繞其旋轉軸線全方位轉動。 [0003]另，第一手腕單元之叉形結構處設有第一電機以及第一 減速元件’第一減速元件用於減速第一電機轉速且驅動 第二手腕單元；第二手腕單元之前端一侧設有第二電機 以及第二減速元件，第二減速元件用於減速第二電機轉 速且驅動第三手腕單元。上述結構增加了手腕單元之體 積及佔用之空間，不利於工業機器人於較狹小操作空間 中之應用，且第二手腕單元及第三手腕單元重量較重， 從而慣性矩較大，不利於提高控制之準確性及快速性。 【發明内容】 098144874 表單編號A0101 第4頁/共19頁 0982076653-0 201121740 [0004] [0005] 鑒於上述内容，有必要提供一種結構緊湊、佔用空間較 小之工業機器人。 ❹ 〇 [0006] 一種工業機器人，包括可繞第一軸線轉動之第一手腕單 元、可繞第二軸線轉動且被第一手腕單元支撐之第二手 腕單元、可繞第三軸線轉動且被第二手腕單元支撐之第 三手腕單元、驅動該第二手腕單元之第一電機及第一傳 動鏈、驅動該第三手腕單元之第二電機及第二傳動鏈以 及控制該第一電機及第二電機分別動作之控制裝置。第 三手腕單元為該工業機器人之最終軸，該第一軸線、第 二軸線及第三轴線相交於一交點。該第二轴線與第三軸 線之夾角大於0度小於90度；該第一傳動鏈包括第一錐齒 輪組，該第一錐齒輪組中之一錐齒輪相對於該第二手腕 單元固定；該第二傳動鏈包括與該第二手腕單元轉動連 接之中間轴及沿中間轴之旋轉軸線間隔設置之第二錐齒 輪組及第三錐齒輪組，該第三錐齒輪組中之一錐齒輪相 對於該第三手腕單元固定，並且該中間軸之旋轉軸線通 過該交點且與第二轴線正交。 上述工業機器人之第二軸線與第三轴線之夾角大於0度小 於90度，即第二軸線與第三軸線斜交，第三手腕單元於 跟隨第二手腕單元轉動時可避免與第一手腕單元相交， 從而第二手腕單元繞第二軸線之轉動角度可不受限制、 作全方位之轉動。另，藉由配置第一至第三錐齒輪組及 中間軸，可將第一電機及第二電機之動力傳遞至第二手 腕單元及第三手腕單元，並可減小第二手腕單元及第三 手腕單元沿各自旋轉軸向之尺寸，使工業機器人結構緊 098144874 表單編號Α0101 第5頁/共19頁 0982076653-0 201121740 湊，佔用空間減小，可實現手腕單元之小型化，使工業 機器人可於更狹窄之作業空間内作業。 【實施方式】 [0007] [0008] [0009] 098144874 下面結合附圖及實施例對本發明之工業機器人作進一步 的詳細說明，並以六軸工業機器人為例進行說明。 圖1所示為本發明實施方式之工業機器人100簡略示意圖 。機器人100為六軸工業機器人，其包括基座11、轉動地 設置於基座11之機架12、可轉動地設置於機架12—端之 大臂13、與大臂13轉動連接之連接手腕14、依次轉動連 接之第一至第三手腕單元15、16、18以及控制裝置19。 其中，第一手腕單元15與連接手腕14轉動連接，第三手 腕單元18作為工業機器人100之末端軸，可用於裝設夾具 、刀具或者探測儀器等末端執行器。控制裝置19用於產 生控制指令，以控制各驅動裝置，如電機等動作，使工 業機器人100獲得預設之位置及姿勢。 第一至第三手腕單元15、16、18可分別繞第一至第三軸 線A、B、C旋轉。第一至第三軸線A、B、C相交於一交點D ，且第二軸線B與第三軸線C斜交，換言之，第二軸線B與 第三軸線C之夾角0大於0度小於90度。第二軸線B可與第 一軸線A正交，亦可與第一軸線A斜交，換言之，第二軸 線B與第一轴線A間之夾角/3可為90度，亦可大於0度小於 90度。本實施方式中，夾角0、/3均為45度。機架12、 大臂13及連接手腕14亦可分別繞軸線121、131、141旋 轉。 因第二軸線B與第三軸線C斜交，當第二手腕單元16帶動 表單編號A0101 第6頁/共19頁 0982076653-0 [0010] 201121740 第三手腕單元18旋轉時，第三手腕單元18及與之連接之 末端執行器可避開與第一手腕單元15相觸碰之位置，從 而第二手腕單元16繞第二軸線Β之轉動範圍不受限制，可 作360度全方位轉動。 [0011] ο [0012] 圖2及圖3示出了第一至第三手腕單元15、16、18之詳細 結構。第二手腕單元16由第一電機21及第一傳動鏈（圖 未標）驅動，第三手腕單元18由第二電機31及第二傳動 鏈（圖未標）驅動。第一電機21及第二電機31均設於第 一手腕單元15上。 第一手腕單元15包括一體成型之第一連接部151及第二連 接部152。第一連接部151大致呈半球形殼體，第二連接 部152形成於第一連接部151上，並大致為沿第一軸線Α方 向延伸之圓柱體。第二連接部152中部沿第一軸線A方向 貫通形成一中空部153。 [0013] 〇 [0014] 第二手腕單元16大致為一圓形蓋體，並貫通開設有複數 連接孔161及一沿第二轴線B方向延伸之安裝孔162。安裝 孔162用於安裝第三手腕單元18。 第二手腕單元16可轉動地設置於第一連接部151之前端一 侧，並被第一手腕單元15懸臂支撐。第三手腕單元18可 轉動地穿設於第二手腕單元16之安裝孔162，並被第二手 腕單元16懸臂支撐。第二手腕單元16與第一手腕單元15 相配合形成一與中空部153相連通之容置部160。容置部 160内可收容第一傳動鏈及第二傳動鏈之部分結構。第一 手腕單元15設有第一交又滚子轴承155，用於支撐第二手 098144874 表單編號A0101 第7頁/共19頁 0982076653-0 201121740 [0015] [0016] [0017] [0018] 腕單元16。第二手腕單元U設有第二交又滾子軸承163， 用於支樓第二手腕單元18。因交叉滚子轴承之内輪與外 輪間，間隔交叉之滚子彼此成直角方式排列，具有可同 柃承受來自多方向之载荷且變形較小之優點，可確保配 合之緊密性以及轉動之剛性。 第一傳動鏈包括第一傳動軸221，設於第一傳動軸221 — 端之第一錐齒輪組223。第一電機21設於第一傳動轴221 之另一端，以驅動第一傳動轴221。第一傳動軸221由轴 承2211可轉動地支撐於第一手腕單元15之中空部153内 。本實施例中，第一傳動軸221沿軸向開設一貫穿孔2212 。第一錐齒輪組223為單級齿.輪，其t 一錐齒輪223a相對 於第二手腕單元16固定設置，可藉由將複數螺紋件156分 別穿設於第二手腕單元16之連接孔161將錐齒輪223a與 第二手腕單元16鎖固。另一錐齒輪223b相對於第一傳動 軸221固定設置，其連接方式可為鍵連接或過盈連接等。 錐齒輪223a中部設有沿軸向貫通之中心孔2232。 第二傳動鏈包括依次設置之第二傳動軸321、第二錐齒輪 組323、中間轴324以及第三錐齒輪組325。 第二傳動軸321穿設於第一傳動轴221之貫穿孔2212，且 其二端分別伸出貫穿孔2212外’並由設於第一傳動軸221 内壁與第二傳動軸321間之軸承3211可轉動支撐。且第二 傳動軸321及第一傳動轴221之旋轉軸線與第一軸線A重合 〇 第二電機31及第二錐齒輪組323分別設置於第二傳動轴 098144874 表單編號A0101 第8頁/共19頁 0982076653-0 201121740 [0019] Ο [0020] 〇 321二端，且於第一軸線Α方向上，第一電機21及第二電 機31相互偏置，且分別設置於第一手腕單元15沿軸向之 相對二侧。第一電機21及第二電機31之輸出軸分別藉由 齒輪組（圖未標）與第一傳動轴221及第二傳動軸321連 接。 中間軸324穿設錐齒輪223a之中心孔2232，且二端分別 藉由軸承3241、3242與第二手腕單元16可轉動連接。中 間軸324之旋轉轴線E通過交點D且與第二轴線B正交，以 使第三手腕單元18跟隨第二手腕單元16轉動時，第二電 機31仍可藉由第二傳動鏈將動力傳送至第三手腕單元18 〇 .......... 戀蒙^ 第二錐齒輪組323及第三錐齒輪組325沿中間軸324之軸 向間隔設置，且分別鄰近中間軸324之二端。第二錐齒輪 組323及第三錐齒輪組325均為單級齒輪。其中，第二錐 齒輪組323中之一錐齒輪323a與第二傳動轴321固定連接 ，另一錐齒輪323b與中間轴324固定連接。錐齒輪323a 與錐齒輪223b於第二轴線B方向上相互偏置，從而錐齒輪 323a及錐齒輪223a於垂直第一軸線A之平面之投影可部 分重合，從而減小整體結構之徑向尺寸。第三錐齒輪組 325中之一錐齒輪325a相對於第三手腕單元18固定設置 以帶動第三手腕單元18繞第三軸線C旋轉，另一錐齒輪 325b與中間轴324固定連接。 上述工業機器人100之第一電機21及第二電機31均設於第 一手腕單元15上，並藉由第一傳動鏈及第二傳動鏈將動 力分別傳遞至第二手腕單元16及第三手腕單元18，第二 098144874 表單編號A0101 第9頁/共19頁 0982076653-0 [0021] 201121740 手腕單元16及第三手腕單元18僅需分別與錐齒輪223a及 錐齒輪323a直接連接，使得第二手腕單元16及第三手腕 單元18沿各自軸向之尺寸均較小，可實現手腕單元之小 型化，有利於工業機器人100於較狹窄之作業空間内與週 圍物體無觸碰地進行作業。同時，還減輕了第二手腕單 元16之慣性矩，有利於對第二手腕單元16及第三手腕單 元18進行準確、快速控制。另，上述第一至第三錐齒輪 組223、323、325均採用單級齒輪，並可採用傳統之錐 齒輪結構，可降低製造成本。 [0022] 以下主要介紹工業機器人100第二、第三手腕單元16、18 之動作情況，工業機器人100之其他機構，例如機架12、 大臂13、第一手腕單元15之動作情況與習知工業機器人 相似。 [0023] 控制裝置19中預設有控制指令，並包括一補償單元（圖 未示）。當控制裝置19發出控制指令驅動第一電機21轉 動時，第一電機21之動力藉由第一傳動鏈傳遞至第二手 腕單元16，使第二手腕單元16繞第二軸線B旋轉。與此同 時，第三手腕單元18將跟隨第二手腕單元16繞第二軸線B 旋轉，第二錐齒輪組323及第三錐齒輪組325之二齒輪相 互嚙合，導致第三手腕單元18繞第三軸線C轉動一定角度 ，此處稱該轉動之角度為跟隨轉動。為防止第三手腕單 元18因跟隨第二手腕單元16之轉動而失去定位之基準， 控制裝置19於控制第二手腕單元16旋轉之同時發出控制 指令控制第二電機31轉動，以驅動第二傳動鏈帶動第三 手腕單元18繞轴線C旋轉相應角度以抵消上述跟隨轉動， 098144874 表單編號A0101 第10頁/共19頁 0982076653-0 201121740 使第二手腕單元16旋轉時，第三手腕單元〗8繞線c仍保持 於當前位置。當需要單獨調整第三手腕單元18繞軸線C之 旋轉角度時，控制裝置19再次發出控制指令使第三手腕 單元18轉動至預設之角度，第三手腕單元18之運動不影 響第二手腕單元16之動作。 [0024]可以理解，工業機器人100之第一傳動鏈及第二傳動鏈還 可進一步增加傳動齒輪之級數以獲得需要之減速比。另 亦可將第一傳動抽321 δ曼為空心結構，而將第一傳動轴 221可轉動地穿設於第二傳動轴321。 [〇〇25] 可以理解，本發明之機器人1〇〇不限於為六轴機器人，其 亦可為具有較少軸數之機器人’如四轴或者五軸機器人 等。 · [0026] 綜上所述，本發明確已符合發明專利之要件，遂依法提 出專利申請。惟’以上所述者僅為本發明之較佳實施方 式，自不能以此限制本索之申請專利範圍.:。舉凡熟悉本 案技藝之人士援依本發明之精神所作之等效修飾或變化 ... η 1..+ .¾、 I | ;ί ，皆應涵蓋於设〒爭請專利旄蕾$:6 【圖式簡單說明】 [0027] 圖1係簡略表示本發明實施例之工業機器人之侧視圖。 [0028] 圖2係圖1所示之機器人之手腕結構之立體組裝圖，圖中 省略了電機及設於電機輸出端之齒輪組。 [0029] 圖3係圖2所示手腕結構沿ΙΙΙ-ΙΠ方向之剖面示意圖。 【主要元件符號說明】 [0030] 機器人100 098144874 表單編號 Α0101 第11頁/共19頁 0982076653-0 201121740 [0031] 基座11 [0032] 機架12 [0033] 大臂13 [0034] 連接手腕14 [0035] 第一手腕單元 15 [0036] 第二手腕單元 16 [0037] 第三手腕單元 18 [0038] 控制裝置19 [0039] 軸線 121、131、 141 [0040] 第一電機21 [0041] 第二電機31 [0042] 第一連接部151 [0043] 第二連接部152 [0044] 中空部1 5 3 [0045] 連接孔161 [0046] 安裝孔162 [0047] 容置部160 [0048] 第一交叉滚子轴承 155 [0049] 第二交叉滾子轴承 163 098144874 表單編號A0101 第12頁/共19頁 0982076653-0 201121740 [0050] 第一傳動軸2 2 1 [0051] 第一錐齒輪組223 [0052] 第二錐齒輪組323 [0053] 第三錐齒輪組325 [0054]軸承 2211、3211、3241、3242 [0055]貫穿孔 2 21 2 Ο [0056] 錐齒輪 223a、223b [0057] 325a、325b 323a、323b [0058] 螺紋件156 [0059] 中心孔 2232 [0060] 第二傳動軸321 [0061] 中間軸324 ❹ 098144874 表單編號A0101 第13頁/共19頁 0982076653-0201121740 VI. Description of the Invention: [Technical Field] The present invention relates to a robot, and more particularly to an industrial robot having a plurality of wrist units connected in series. [Prior Art] [〇〇〇2] An industrial robot generally has a first wrist unit rotatable about a first axis, and a front side of the first wrist unit forms a fork structure; rotatably disposed on the fork a second wrist unit between the two sides of the shape structure; and a third wrist unit rotatably disposed at a front end side of the second wrist unit. The second wrist unit acts as the end shaft of the Guardian robot, such as the sixth of the six-axis industrial robots, which can be used to install end-effectors such as dislocations, cutting tools and detectors to perform various tasks. The rotation axes of the first and third wrist units are generally orthogonal to the rotation axis I: . . . of the second wrist unit, respectively, so that the third wrist unit and the end effector follow During the rotation of the second wrist unit, the first wrist unit is easily touched, so that the rotation angle of the second wrist unit is limited, and the rotation of the second wrist unit cannot be performed in all directions. [0003] In addition, the first motor and the first deceleration element are provided at the fork structure of the first wrist unit. The first deceleration element is used to decelerate the first motor speed and drive the second wrist unit; the front end of the second wrist unit is The second motor and the second reduction element are provided on the side, and the second reduction element is used to decelerate the second motor speed and drive the third wrist unit. The above structure increases the volume and space occupied by the wrist unit, which is disadvantageous for the application of the industrial robot in the narrow operation space, and the weight of the second wrist unit and the third wrist unit is heavier, so that the moment of inertia is large, which is not conducive to improving the control. Accuracy and speed. SUMMARY OF THE INVENTION 098144874 Form No. A0101 Page 4 of 19 0982076653-0 201121740 [0004] [0005] In view of the above, it is necessary to provide an industrial robot with a compact structure and a small footprint.工业 〇 [0006] An industrial robot comprising a first wrist unit rotatable about a first axis, a second wrist unit rotatable about a second axis and supported by a first wrist unit, rotatable about a third axis and being a third wrist unit supported by the second-hand wrist unit, a first motor driving the second wrist unit and a first transmission chain, a second motor and a second transmission chain driving the third wrist unit, and controlling the first motor and the second The control device for the motor to operate separately. The third wrist unit is the final shaft of the industrial robot, and the first axis, the second axis, and the third axis intersect at an intersection. The angle between the second axis and the third axis is greater than 0 degrees and less than 90 degrees; the first transmission chain includes a first bevel gear set, and one bevel gear of the first bevel gear set is fixed relative to the second wrist unit; The second transmission chain includes an intermediate shaft rotatably coupled to the second wrist unit and a second bevel gear set and a third bevel gear set spaced apart along an axis of rotation of the intermediate shaft, one bevel gear of the third bevel gear set Fixed relative to the third wrist unit, and the axis of rotation of the intermediate shaft passes through the intersection and is orthogonal to the second axis. The angle between the second axis of the industrial robot and the third axis is greater than 0 degrees and less than 90 degrees, that is, the second axis is oblique to the third axis, and the third wrist unit can avoid the first wrist when following the rotation of the second wrist unit. The units intersect so that the angle of rotation of the second wrist unit about the second axis is unrestricted and omnidirectional. In addition, by configuring the first to third bevel gear sets and the intermediate shaft, the power of the first motor and the second motor can be transmitted to the second wrist unit and the third wrist unit, and the second wrist unit and the second wrist unit can be reduced. The dimensions of the three wrist units along their respective axes of rotation make the structure of the industrial robot tight 098144874 Form No. Α0101 Page 5 / Total 19 pages 0982076653-0 201121740 Together, the footprint is reduced, the wrist unit can be miniaturized, and the industrial robot can be Work in a narrower working space. [Embodiment] [0007] [0009] [0009] 098144874 The industrial robot of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, and a six-axis industrial robot will be described as an example. Fig. 1 is a schematic view showing an industrial robot 100 according to an embodiment of the present invention. The robot 100 is a six-axis industrial robot including a base 11, a frame 12 rotatably disposed on the base 11, a boom 13 rotatably disposed at the end of the frame 12, and a connecting wrist rotatably coupled to the boom 13. 14. The first to third wrist units 15, 16, 18 and the control device 19 are sequentially rotated. Among them, the first wrist unit 15 is rotatably connected to the connecting wrist 14, and the third wrist unit 18 is used as an end shaft of the industrial robot 100, and can be used for installing an end effector such as a jig, a cutter or a detecting instrument. The control device 19 is operative to generate control commands for controlling the actions of the respective drive devices, such as motors, to cause the industrial robot 100 to obtain a preset position and posture. The first to third wrist units 15, 16, 18 are rotatable about the first to third axes A, B, and C, respectively. The first to third axes A, B, and C intersect at an intersection D, and the second axis B is oblique to the third axis C. In other words, the angle 0 between the second axis B and the third axis C is greater than 0 degrees and less than 90 degrees. . The second axis B may be orthogonal to the first axis A or may be oblique to the first axis A. In other words, the angle /3 between the second axis B and the first axis A may be 90 degrees or greater than 0 degrees. Less than 90 degrees. In the present embodiment, the angles 0 and /3 are both 45 degrees. The frame 12, the boom 13 and the connecting wrist 14 can also be rotated about the axes 121, 131, 141, respectively. Since the second axis B is oblique to the third axis C, when the second wrist unit 16 drives the form number A0101, page 6 / 19 pages 0982076653-0 [0010] 201121740, the third wrist unit 18 rotates, the third wrist unit 18 And the end effector connected thereto can avoid the position touched by the first wrist unit 15, so that the rotation range of the second wrist unit 16 about the second axis is not limited, and can be rotated 360 degrees. [0012] FIGS. 2 and 3 show the detailed structures of the first to third wrist units 15, 16, 18. The second wrist unit 16 is driven by the first motor 21 and the first transmission chain (not shown), and the third wrist unit 18 is driven by the second motor 31 and the second transmission chain (not shown). The first motor 21 and the second motor 31 are both disposed on the first wrist unit 15. The first wrist unit 15 includes an integrally formed first connecting portion 151 and a second connecting portion 152. The first connecting portion 151 is substantially a hemispherical housing, and the second connecting portion 152 is formed on the first connecting portion 151 and is substantially a cylindrical body extending in the Α direction of the first axis. A central portion of the second connecting portion 152 penetrates in the direction of the first axis A to form a hollow portion 153. [0013] The second wrist unit 16 is substantially a circular cover body, and has a plurality of connection holes 161 and a mounting hole 162 extending in the second axis B direction. Mounting holes 162 are used to mount the third wrist unit 18. The second wrist unit 16 is rotatably disposed on the front side of the first connecting portion 151 and is cantilevered by the first wrist unit 15. The third wrist unit 18 is rotatably threaded through the mounting hole 162 of the second wrist unit 16 and is cantilevered by the second wrist unit 16. The second wrist unit 16 cooperates with the first wrist unit 15 to form a receiving portion 160 that communicates with the hollow portion 153. The receiving portion 160 can accommodate a part of the structure of the first transmission chain and the second transmission chain. The first wrist unit 15 is provided with a first roller bearing 155 for supporting the second hand 098144874. Form No. A0101 Page 7 / 19 pages 0982076653-0 201121740 [0015] [0017] [0018] Unit 16. The second wrist unit U is provided with a second roller bearing 163 for the second wrist unit 18 of the branch. Because the inner and outer wheels of the crossed roller bearing are arranged at right angles to each other, they have the advantage of being able to withstand loads from multiple directions and having less deformation, ensuring the tightness of the fit and the rigidity of the rotation. The first transmission chain includes a first transmission shaft 221 and a first bevel gear set 223 disposed at the end of the first transmission shaft 221. The first motor 21 is disposed at the other end of the first transmission shaft 221 to drive the first transmission shaft 221. The first transmission shaft 221 is rotatably supported by the bearing 2211 in the hollow portion 153 of the first wrist unit 15. In this embodiment, the first transmission shaft 221 defines a permanent through hole 2212 in the axial direction. The first bevel gear set 223 is a single-stage gear wheel. The t-bevel gear 223a is fixedly disposed with respect to the second wrist unit 16 and can be respectively disposed through the connecting hole 161 of the second wrist unit 16 by the plurality of screw members 156. The bevel gear 223a and the second wrist unit 16 are locked. The other bevel gear 223b is fixedly disposed with respect to the first transmission shaft 221, and may be connected by a key connection or an interference connection or the like. A central hole 2232 is formed in the middle of the bevel gear 223a in the axial direction. The second drive train includes a second drive shaft 321, a second bevel gear set 323, an intermediate shaft 324, and a third bevel gear set 325. The second transmission shaft 321 is disposed through the through hole 2212 of the first transmission shaft 221, and the two ends of the second transmission shaft 321 extend outwardly from the through hole 2212 and are supported by the bearing 3211 disposed between the inner wall of the first transmission shaft 221 and the second transmission shaft 321 Rotating support. The rotation axes of the second transmission shaft 321 and the first transmission shaft 221 coincide with the first axis A. The second motor 31 and the second bevel gear set 323 are respectively disposed on the second transmission shaft 098144874. Form No. A0101 Page 8 of 19 Page 0982076653-0 201121740 [0019] [0020] 〇321 two ends, and in the first axis Α direction, the first motor 21 and the second motor 31 are mutually offset, and are respectively disposed along the axis of the first wrist unit 15 To the opposite side. The output shafts of the first motor 21 and the second motor 31 are respectively coupled to the first transmission shaft 221 and the second transmission shaft 321 by a gear set (not shown). The intermediate shaft 324 is threaded through the central bore 2232 of the bevel gear 223a, and the two ends are rotatably coupled to the second wrist unit 16 by bearings 3241, 3242, respectively. When the rotation axis E of the intermediate shaft 324 passes through the intersection D and is orthogonal to the second axis B, so that the third wrist unit 18 follows the rotation of the second wrist unit 16, the second motor 31 can still be driven by the second transmission chain. Power is transmitted to the third wrist unit 18 〇.......... 蒙蒙^ The second bevel gear set 323 and the third bevel gear set 325 are axially spaced along the intermediate shaft 324 and are adjacent to the intermediate shaft, respectively. The second end of 324. The second bevel gear set 323 and the third bevel gear set 325 are each a single stage gear. The bevel gear 323a of the second bevel gear set 323 is fixedly coupled to the second transmission shaft 321, and the other bevel gear 323b is fixedly coupled to the intermediate shaft 324. The bevel gear 323a and the bevel gear 223b are mutually offset in the direction of the second axis B, so that the projections of the bevel gear 323a and the bevel gear 223a on the plane perpendicular to the first axis A may partially coincide, thereby reducing the radial dimension of the overall structure. . One of the bevel gears 325 of the third bevel gear set 325 is fixedly disposed relative to the third wrist unit 18 to drive the third wrist unit 18 to rotate about the third axis C, and the other bevel gear 325b is fixedly coupled to the intermediate shaft 324. The first motor 21 and the second motor 31 of the industrial robot 100 are respectively disposed on the first wrist unit 15 and transmit power to the second wrist unit 16 and the third wrist respectively through the first transmission chain and the second transmission chain. Unit 18, second 098144874 Form No. A0101 Page 9/Total 19 Page 0982076653-0 [0021] 201121740 The wrist unit 16 and the third wrist unit 18 need only be directly connected to the bevel gear 223a and the bevel gear 323a, respectively, so that the second wrist The unit 16 and the third wrist unit 18 are small in size in each axial direction, and the wrist unit can be miniaturized, which is advantageous for the industrial robot 100 to work without touching the surrounding objects in a narrow working space. At the same time, the moment of inertia of the second wrist unit 16 is also reduced, which facilitates accurate and rapid control of the second wrist unit 16 and the third wrist unit 18. Further, the first to third bevel gear sets 223, 323, and 325 are each a single-stage gear, and a conventional bevel gear structure can be employed, which can reduce the manufacturing cost. [0022] The following mainly describes the operation of the second and third wrist units 16, 18 of the industrial robot 100, and the operation and other functions of other mechanisms of the industrial robot 100, such as the frame 12, the boom 13, and the first wrist unit 15. Industrial robots are similar. [0023] The control device 19 is pre-configured with a control command and includes a compensation unit (not shown). When the control device 19 issues a control command to drive the first motor 21 to rotate, the power of the first motor 21 is transmitted to the second wrist unit 16 by the first chain, and the second wrist unit 16 is rotated about the second axis B. At the same time, the third wrist unit 18 will follow the second wrist unit 16 about the second axis B, and the two gears of the second bevel gear set 323 and the third bevel gear set 325 mesh with each other, resulting in the third wrist unit 18 being wound around the second wrist unit 18 The three axes C are rotated by a certain angle, and the angle of the rotation is referred to herein as following rotation. In order to prevent the third wrist unit 18 from losing the reference of the positioning due to the rotation of the second wrist unit 16, the control device 19 issues a control command to control the rotation of the second motor 31 while controlling the rotation of the second wrist unit 16 to drive the second transmission. The chain drives the third wrist unit 18 to rotate about a corresponding angle around the axis C to counteract the following following rotation, 098144874 Form No. A0101 Page 10 / Total 19 Page 0982076653-0 201121740 When the second wrist unit 16 is rotated, the third wrist unit is 8 The winding c remains in the current position. When it is necessary to separately adjust the rotation angle of the third wrist unit 18 about the axis C, the control device 19 again issues a control command to rotate the third wrist unit 18 to a preset angle, and the movement of the third wrist unit 18 does not affect the second wrist unit. 16 action. It will be appreciated that the first drive train and the second drive train of the industrial robot 100 may further increase the number of stages of the drive gear to achieve the desired reduction ratio. Alternatively, the first transmission 321 can be a hollow structure, and the first transmission shaft 221 can be rotatably disposed through the second transmission shaft 321. [〇〇25] It can be understood that the robot 1 of the present invention is not limited to a six-axis robot, and may be a robot having a small number of axes such as a four-axis or five-axis robot. [0026] In summary, the present invention has indeed met the requirements of the invention patent, and the patent application is filed according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Anyone who is familiar with the skill of this case will be able to use the equivalent modification or change in accordance with the spirit of the present invention... η 1..+ .3⁄4, I | ; ί , all should be included in the design of the patent 旄蕾 $:6 [ BRIEF DESCRIPTION OF THE DRAWINGS [0027] FIG. 1 is a side view schematically showing an industrial robot according to an embodiment of the present invention. 2 is a perspective assembled view of the wrist structure of the robot shown in FIG. 1, in which the motor and the gear set provided at the output end of the motor are omitted. 3 is a schematic cross-sectional view of the wrist structure shown in FIG. 2 along the ΙΙΙ-ΙΠ direction. [Main component symbol description] [0030] Robot 100 098144874 Form number Α 0101 Page 11 / 19 pages 0982076653-0 201121740 [0031] Base 11 [0032] Rack 12 [0033] Boom 13 [0034] Connecting the wrist 14 [0035] First Wrist Unit 15 [0036] Second Wrist Unit 16 [0037] Third Wrist Unit 18 [0038] Control Device 19 [0039] Axis 121, 131, 141 [0040] First Motor 21 [0041] Second motor 31 [0042] first connecting portion 151 [0043] second connecting portion 152 [0044] hollow portion 1 5 3 [0045] connecting hole 161 [0046] mounting hole 162 [0048] accommodating portion 160 [0048] A crossed roller bearing 155 [0049] Second crossed roller bearing 163 098144874 Form No. A0101 Page 12 of 19 0982076653-0 201121740 [0050] First drive shaft 2 2 1 [0051] First bevel gear set 223 [0052] Second Bevel Gear Set 323 [0053] Third Bevel Gear Set 325 [0054] Bearings 2211, 3211, 3241, 3242 [0055] Through Hole 2 21 2 Ο [0056] Bevel Gears 223a, 223b [0057] 325a 325b 323a, 323b [0058] Screw 156 [0059] Center Hole 2232 [0060] Second Drive Shaft 321 [0061] Intermediate shaft 324 ❹ 098144874 Form number A0101 Page 13 of 19 0982076653-0