مخفض آلية الدوران Toshiba SG025E-138 20/925447 لـ حفارة صغيرة Yanmar VIO70 VIO75 VIO80 CASE CX75 CX75SR CX80 C Sumitomo SH75X-3 SH75U-2 JCB 8080 8085 ZTS

1. Product Identification
Component: Main Hydraulic Swing Drive Motor Assembly (Upper-Structure Rotation Device)

Manufacturer Model Number: Toshiba / HYEST SG025E-138 (SG Series Architecture)

OEM Cross-Reference Part Numbers:

Yanmar: 172187-73311, 172187-73411, 172187-73370 (17218773311, 17218773411, 17218773370)

CASE : KAC0177

JCB: 20/925447, 20/951631, 20/951632 (20925447, 20951631, 20951632)

Machine Compatibility:

Yanmar: VIO70 / VIO75 / VIO80

CASE: CX75 / CX75SR / CX80 / CX80C

Sumitomo: SH75X-3 / SH75U-2

JCB: 8080 / 8085 ZTS

Link-Belt: 75 / 80 X3

Yuchai: YC85 / YC85-8

XCMG: XE80 / XE80C

Sunward: SWE80 / SWE90 Midi Excavators

Condition: Genuine Original New / Premium OEM Specification Equivalent

2. Technical Specifications
Motor Type: Fixed Displacement Axial Piston Swing Motor with Integrated Planetary Gearbox

Output Performance: Calibrated displacement, rotation speed, and torque profile engineered specifically for 7.0 to 9.0-ton midi excavator upper-structure swing controls.

Integrated Control Network: Features built-in crossover relief valves, anti-drift check valves, anti-cavitation logic, and an automatic mechanical dynamic parking brake.

Drive Interface: Precision-machined mounting flange and heavy-duty output shaft designed for direct engagement with the machine's slew ring bearing.

3. Critical Installation Requirements
Swing Motor Housing Priming (Mandatory)
Before starting the engine or engaging the swing control lever, pre-fill the swing motor housing with clean, fresh hydraulic fluid through its highest case drain port. Running an axial piston motor dry—even for a few track turns or swing passes—will score the cylinder block and piston slippers, causing immediate total failure.

Verify Case Drain Line Pressure
Inspect the low-pressure case drain hose leading back to the hydraulic oil reservoir. Ensure there are no kinks, sharp bends, or flow restrictions. High backpressure in the case drain line will blow out the main shaft seal and mix hydraulic fluid with gearbox lubricant.

Air Bleeding & Initial Startup Procedure
After mounting and filling the housing, loosen the top air bleed plug on the motor manifold. Crank the engine with the fuel delivery disabled until clear, bubble-free hydraulic oil flows out, then retighten the plug. Allow the machine to idle at low RPM with zero load for 10 to 15 minutes to purge remaining air.

Hydraulic System Decontamination
If replacing a motor that suffered catastrophic mechanical failure, thoroughly drain and flush the main hydraulic reservoir, clean oil cooler lines, and replace all return, suction, and pilot filter elements prior to starting the machine.

4. Frequently Asked Questions (FAQ)
Q: Are Yanmar part numbers 172187-73311, 172187-73411, and 172187-73370 fully interchangeable?
A: Yes. These part numbers represent standard Yanmar factory revisions, production updates, and supersessions across the VIO70, VIO75, and VIO80 model lines. All cross-reference directly to the Toshiba SG025E-138 platform with identical mounting bolt patterns, shaft splines, and hydraulic port threads.

Q: My JCB 8080 or Yanmar VIO75 drifts or rotates on its own when working on a hill. Is the swing motor failing?
A: Upper-structure drift or over-swing when stopping usually indicates worn internal mechanical brake friction discs, compromised crossover shock relief valve seats, or scored barrel-to-plate surfaces inside the motor housing. Replacing the motor assembly restores exact position holding and swing stopping control.

Q: Does this unit arrive complete with the control valve manifold installed?
A: Yes. The Toshiba SG025E-138 is delivered as a complete drop-in assembly, pre-assembled with the axial piston motor section, integrated planetary reduction gear stage, and pre-calibrated brake/relief valve manifold block.

5. Shipping & Logistics
Packaging: Preserved with rust-inhibiting storage oil, fitted with plastic port caps, and bolted securely inside an export-safe wooden crate.

Transit Time: Global express air freight via DHL/FedEx/UPS typically delivers within 3 to 7 business days directly to your workshop or job site.