330D, 336D and 340D Excavators Hydraulic System – Swivel



Illustration 1 g01171766

Swivel

(1) Retainer

(2) Cover

(3) Drain port

(4) Drain hole

(5) Port

(6) Seal

(7) Port

(8) Port

(9) Housing

(10) Port

(11) Port

(12) Flange

(13) Seal

(14) Rotor

(15) Port

(16) Port

(17) Port

(18) Port

(19) Port

(20) Port

(21) Swivel

Table 1
Identification Of Port And Circuit    
Ports (Housing)     Ports (Rotor)     Circuit    
7     17     Right travel (reverse)    
10     20     Right travel (forward)    
8     19     Left travel (forward)    
5     16     Left travel (reverse)    
3     18     Drain    
11     15     Change of Travel speed    

The swivel accomplishes two functions. The swivel supplies pump oil from the upper structure to the travel motors of the lower structure. The upper structure swings. The lower structure does not swing. Swivel (21) returns oil from the travel motors to the hydraulic tank.

Housing (9) is bolted to the upper structure at flange (12). Rotor (14) rotates within housing (9). A support arm is bolted to rotor (14) in order to prevent rotation. The ports of housing (9) are open to the ports of rotor (14). The passages in housing (9) and the passages in rotor (14) connect the ports.

Seal (6) for high pressure and seal (13) for low pressure are provided between the sliding surfaces of housing (9) and rotor (14). Seals (6) and (13) prevent oil leakage between the passages.