The upper turntable of rotary device is one of the three parts of hydraulic excavator. In addition to the engine, hydraulic system, cab, counterweight, oil tank, etc., there is also a very important part in the rotary table - rotary device.

　　液壓挖掘機回轉裝置由回轉臺、回轉支承和回轉機構組成。旋轉裝置的外閥座環通過螺栓與轉盤連接，內帶齒的閥座環通過螺栓與底部框架連接，內、外圈之間有滾動體。挖掘機工作裝置作用于轉盤上的垂直載荷、水平載荷和傾覆力矩通過旋轉支承的外座環、滾動體和內座傳遞到底架上。旋轉機構的殼體固定在轉盤上，其小齒輪與旋轉支架內座環上的齒環相嚙合。

　　The slewing device of hydraulic excavator is composed of slewing table, slewing bearing and slewing mechanism. The outer valve seat ring of the rotating device is connected with the rotary table by bolts, the inner toothed valve seat ring is connected with the bottom frame by bolts, and there is a rolling body between the inner and outer rings. The vertical load, horizontal load and overturning moment of the working device of the excavator act on the turntable are transmitted to the base frame through the outer seat ring, rolling body and inner seat of the rotary support. The shell of the rotating mechanism is fixed on the rotary table, and its pinion gear is meshed with the tooth ring on the seat ring in the rotating support.

　　液壓挖掘機的回轉裝置必須能夠支撐轉臺的固定部分。不要翻車，要使轉彎輕而靈活。因此，液壓挖掘機設有回轉支承裝置(支承)和回轉傳動裝置(帶動轉盤轉向回轉)，統稱液壓挖掘機回轉裝置。

　　The slewing device of the hydraulic excavator must be able to support the fixed part of the turntable. Don't roll over. Make the turn light and flexible. Therefore, the hydraulic excavator is equipped with a slewing bearing device (support) and a slewing transmission device (driving the rotary table to turn), which are collectively referred to as the slewing device of the hydraulic excavator.

　　回轉支承的主要結構形式

　　Main structure of slewing bearing

　　1. 由擺動液壓馬達驅動的旋轉立柱支架如圖3-2所示。它由固定在旋轉體1上的上下支承軸4和6，以及上下支承軸3和7組成。軸承座用螺栓固定在框架5上。旋轉體與支承軸構成旋轉柱，旋轉柱插入軸承座的軸承內。殼體固定在機架5上的擺動式液壓缸輸出軸上，插入下支撐軸6，帶動旋轉體相對于機架旋轉。“匚”形式的轉子經常讓它,為了避免碰撞與回轉機構。工作裝置鉸接在旋轉體上，并隨旋轉體旋轉。

　　1. The rotating column bracket driven by the swing hydraulic motor is shown in Figure 3-2. It consists of upper and lower supporting shafts 4 and 6 fixed on the rotating body 1, and upper and lower supporting shafts 3 and 7. The bearing pedestal is bolted to frame 5. The rotating body and the supporting shaft form a rotating column which is inserted into the bearing of the bearing seat. The shell is fixed on the output shaft of the swinging hydraulic cylinder on the frame 5, and the lower support shaft 6 is inserted to drive the rotating body to rotate relative to the frame. The "zhe" type of rotor often lets it, in order to avoid collision with the slewing mechanism. The working device is hinged on the rotating body and rotates with the rotating body.

　　2. 滾動軸承回轉軸承實際上是一種大直徑滾動軸承。它與普通軸承的區別是它的速度很慢。挖掘機的轉速范圍為5~11r/min。此外，一般軸承的滾道直徑與高度之比為4~5，而回轉軸承可達10~15。因此，該軸承的剛度較差，工作時應依靠支撐連接結構來保證。

　　2. The rolling bearing is actually a large diameter rolling bearing. The biggest difference between it and ordinary bearing is its slow speed. The speed range of excavator is 5 ~ 11R / min. In addition, the ratio of the center diameter to the height of the raceway of the general bearing is 4-5, while that of the rotary bearing is 10-15. Therefore, the stiffness of the bearing is poor, and the support connection structure should be relied on to ensure the work.

　　典型的滾動軸承式回轉軸承結構。內環或外圈可加工成內環或外圈。帶有齒輪環的閥座環是一種固定環，用螺栓4和5沿圓周分布固定在底座上。無齒座環為旋轉環，通過螺栓與挖掘機轉臺連接。裝配時，先將閥座環1、3和滾動體8安裝成一個完整的部件，然后與挖掘機裝配。為保證轉動靈活，防止熱膨脹后卡死現象，回轉環應留有一定的軸向間隙。由于加工誤差和滾道和滾體的磨損，間隙會發生變化。因此，在兩個環之間有一個調整墊圈2，以調整裝配和修理期間的間隙。

　　Typical rolling bearing type slewing bearing structure. The inner ring or outer ring can be processed into the inner ring or outer ring. The seat ring with gear ring is a fixed ring, which is fixed on the base with bolts 4 and 5 along the circumference. The toothless seat ring is a rotating ring, which is connected with the turntable of the excavator through bolts. When assembling, first install the seat rings 1, 3 and the rolling elements 8 into a complete part, and then assemble with the excavator. In order to ensure the flexibility of rotation and prevent the seizure after thermal expansion, a certain axial clearance should be reserved for the rotating ring. Due to machining error and wear of raceway and roller body, clearance will change. Therefore, there is an adjusting washer 2 between the two rings in order to adjust the clearance during assembly and repair.

　　隔離體7是用來防止相鄰的滾壓體8的擠壓，減少滾壓體的磨損，起到導向作用。卷軸可以是一個球或滾軸。滾動軸承式回轉支承機構廣泛應用于全回轉液壓挖掘機中。它是在普通滾動軸承的基礎上發展起來的，相當于結構上的擴大滾動軸承。它與傳統的滾動軸承相比,具有體積小,結構緊湊,承載能力大,旋轉摩擦阻力小,小輥之間的差距和跟蹤,維護方便,使用壽命長,容易實現三個特點的一系列優勢,這是與普通滾動軸承相比,及其特點:普通滾動軸承的內圈與外圈之間的剛度依靠軸與軸承總成之間的剛度來保證，同時有轉盤和底盤來保證;回轉支承的轉速較低，通常承受軸向載荷，因此軌跡上接觸點的周數較少。

　　The separator 7 is used to prevent the extrusion of the adjacent rolling body 8, reduce the wear of the rolling body and play a guiding role. The reel can be a ball or a roller. The rolling bearing type slewing bearing mechanism is widely used in the full rotation hydraulic excavator. It is developed on the basis of common rolling bearing, which is equivalent to expanding rolling bearing in structure. Compared with the traditional rolling bearing, it has a series of advantages, such as small volume, compact structure, large bearing capacity, small rotating friction resistance, gap and tracking between small rolls, convenient maintenance, long service life, and easy to realize three characteristics. This is compared with the ordinary rolling bearing, Its characteristics: the rigidity between inner ring and outer ring of common rolling bearing depends on the rigidity between shaft and bearing assembly, and is guaranteed by turntable and chassis at the same time; the rotation speed of slewing bearing is low, usually bearing axial load, so the number of contact points on the track is less.