705-12-40110 hydraulic gear pump for Komatsu wheel loader WA500-3

What is a gear pump?

A gear pump is a type of positive displacement (PD) pump.  It moves a fluid by repeatedly enclosing a fixed volume using interlocking cogs or gears, transferring it mechanically using a cyclic pumping action. It delivers a smooth pulse-free flow proportional to the rotational speed of its gears. Gear pumps use the actions of rotating cogs or gears to transfer fluids.  The rotating element develops a liquid seal with the pump casing and creates suction at the pump inlet.  Fluid, drawn into the pump, is enclosed within the cavities of its rotating gears and transferred to the discharge. There are two basic designs of gear pump: external and internal gear pump.

What are the main features and benefits of a gear pump?

Gear pumps are compact and simple with a limited number of moving parts. They are unable to match the pressure generated by reciprocating pumps or the flow rates of centrifugal pumps but offer higher pressures and throughputs than vane or lobe pumps.

Gear pumps are particularly suited for pumping oils and other high viscosity fluids. Of the two designs, external gear pumps are capable of sustaining higher pressures (up to 3000 psi) and flow rates because of the more rigid shaft support and closer tolerances.

Internal gear pumps have better suction capabilities and are suited to high viscosity fluids, although they have a useful operating range from 1cP to over 1,000,000cP. Since output is directly proportional to rotational speed, gear pumps are commonly used for metering and blending operations. Gear pumps can be engineered to handle aggressive liquids. While they are commonly made from cast iron or stainless steel, new alloys and composites allow the pumps to handle corrosive liquids such as sulphuric acid, sodium hypochlorite, ferric chloride and sodium hydroxide.

External gear pumps can also be used in hydraulic power applications, typically in vehicles, lifting machinery and mobile plant equipment. Driving a gear pump in reverse, using oil pumped from elsewhere in a system (normally by a tandem pump in the engine), creates a hydraulic motor. This is particularly useful to provide power in areas where electrical equipment is bulky, costly or inconvenient. Tractors, for example, rely on engine-driven external gear pumps to power their services.

Basic design and structure of the external gear pumps for Construction Machinery:

External gear pumps, the most popular pumps used in modern hydraulics systems. These hydraulic gear pumps and motors can work under heavy duty operating conditions and transmit high hydraulic power, feature good hydraulic, mechanical and volumetric efficiency, low noise level and, last but not least, compact dimensions and low weight to power ratio. Ideal for both industrial and mobile industry sectors.

The basic components consist of a gear set supported by two aluminum bushings, a body, a securing flange and a cover. The shaft of the driving gear projecting beyond the flange mounts a seal ring coupled with a metallic ring to strengthen the setup. Both rings are held in place by an elastic securing ring. The body is made of a special aluminium alloy with high strength for minimized deformation even when subject to high pressure.

There are also cast iron bodied pumps and motors now available for applications requiring high pressures, optimal performance and endurance. Flange and cover are made out of cast iron or aluminium alloy, depending on the model series type, manufactured through a process of continuous flow casting and with a final surface treatment of phosphating.

Gears are made of special grade steel. Their manufacturing process includes case-hardening and quench hardening. The gears are ground and fine finished to achieve a high degree of surface finishing. Good tooth profile design and geometric proportions ensure low pulsation levels and low noise levels during motor operation.

Bushings are made of special low-friction and high-resistant aluminium alloy and manufactured from die-casting that have excellent high strength and anti-friction characteristics. Also equipped with anti-friction DU bearings with tight tolerance.

Special and symmetric compensation zones onto bushings, insulated by special preformed seals with special anti-extrusion ring, allow full free axial and radial movement to the bushings, which is proportional to motor operating pressure. In this way, internal leakage is dramatically reduced, ensuring very good pump performance (both in terms of mechanical and total efficiencies) and proper lubrication of pump moving parts.

Why buy Wanxun hydraulic gear pump?

Shaft sleeves are imported from DAIDO Japan.

Oil sealing is made by NOK Japan.

Hydraulic pump Case is an extrusion molding which is produced by extruding machine (press power is 7200 Ton). Pls check pic as below:

Smooth surface, hard density of material.

Complete variety for international pump parts (more than 300 kinds of Hydraulic pumps)

Note before quotation:

For fast and accurate quotation information, we need more details:

1. Your specs model of construction Vehicle

2. The hydraulic pump part number  (most important)

3. The photos of pump

4. The direction of rotation for the pump (anticlockwise or  clockwise)

Installation and Operation Manual of the gear pump:

The Hydraulic Oil must be clean and fresh, the bad condition of Oil will damage and reduce working life of pump. Please add in HYD Oil in the pump before installation. It will affect working efficiency of pumps when the old pump and new pump connect. In developed industry market, the spare parts of gear pump achieved sophisticated. Therefore, check of clean oil with operation before using pump. The installation should be according to the ex-works technical documents of gear pump, and related specification of this manual, also the pump structure should be taken into consideration.

1) Before installation, please fill the inlet holes with enough clean hydraulic oil, please use new oil to ensure the oil quality is clean. Only when the oil is filled up, when the machine is started, a vacuum will be formed inside the pump body, so there will be pressure/power to vehicles.

2) Before installing the new pump, clean the filter element, oil pipe and oil tank to ensure that the hydraulic oil is sufficiently clean.

3) Please check whether the pressure control valve of the vehicle is stuck by long-term accumulated impurities, and clean it up in time. Otherwise, the valve needle will be insensitive, cannot open and close normally, and the pressure will be abnormal.

4) Run the vehicle at low speed for about 15 minutes, and then put it into work after everything is normal.

The Gear Pumps Maintenance Issues:

Gear pumps require good, robust installation, a PRV to protect the pump from overpressure and an assured supply of clean liquid. Those with outboard bearings require the bearings to be lubricated. Mechanical seals introduce there own set of problems and if possible select pumps that do not use them. If mechanical seals are fitted it becomes critical that shafts run true and the process pressures and flows are steady and do not fluctuate wildly to load up the bearings and gear teeth unevenly.

The gear teeth must not be run dry. Unlubricated teeth will rub together and wear away. If these pumps are run dry and temperatures rise the cogs will expand and start rubbing on the housing. This will tear-up the housing and teeth. Either the pump is destroyed or the fine housing clearances are lost which then allows recirculation within the pump. The best protection against dry running is to install a flow switch in the suction line that turns power off to the pump if there is no flow.

Application for komatsu/Shantui/Kawasaki/Caterpillar machine:

Wanxun Hydraulic Gear Pump Factory Show:

More than 30 years experience in gear pump design and research. Professional

specialized in hydraulic pump components of Komatsu construction Vehicle since 1983.

Our products include: Komatsu and Caterpillar Steering pumps, hydraulic pumps, gear pumps, work pumps, valves, crankshafts, frictions, PCBN, pistons, Shan Tui torques, bearings, cylinder sleeves, piston rings, motors, generators, filter elements, service kits, superchargers and fuel injectors. Our products are used in bulldozers, loaders, excavators, such as D80A-12, D85A-18, D150A-1, D155A-1, D155A-3, D355A-3, WA470, WA470-3, WA500-3, Shan Tui, Huang He TY130, TY160, TY180, TY220, TY230, TY320, SD13, SD16, SD22, SD42 and SD42-3.

Wanxun Hydraulic Gear Pump Workshop:

We care much on the quality control system in each step, from the raw material choosen, machine use, professional worker to make sure client get the best quality product!

Wanxun test system:

Each piece hydraulic gear pump is tested by worker to make sure each customer from the global get the rest assured product, we highly welcome you to test the sample!

Wanxun Hydraulic Gear Pump Series:

Our package warehouse, all the package is ready when you need the hydraulic gear pump, we can deliver it as fast as we could!

My factory take exibition around the world:

We are confident of our quality, and get approved and positive feedback from clients from the global!