Constant pressure pump is generally used in such hydraulic systems: the beginning of the requirements of low-voltage fast-forward, and then slowly turned around, and finally stops moving and packing, as the hydraulic machine is. Here variable pump care - the pressure is constant pressure pump set packing system pressure required. Here, "the decision by the load pressure of the hydraulic system, and the relief is applied to define the" basic principles should say is met. To better understand the pump control system, can be considered to "determine the variable displacement pump system pressure maintenance by the load - while adding to the limit by the constant pressure pump." Like the example of the press reaction force moldings can be large, depending how much adjustment is applied by the constant pressure pump. Manual variable displacement axial piston pump, which is characterized by the body and body composition variables; body from the pump casing (12), drive shaft (1), the cylinder (15), a plurality of pistons (11), the shoe (10 ), return plate (9), the return spring (13), the sleeve (20), one-way thrust ball bearings (18), a small spring (14), ball joints (8), thimble (22), retainer holes (19), with the oil pan (16) and pump body (17) composition; shaft (1) and the cylinder (15) between the splined coupling, a plurality of plungers (11) respectively mounted in the cylinder (15) hole on the plunger, the plunger (11) of the ball head and the shoe (10) is associated, the shoe (10) in the return plate hole card (9), the return plate (9) of the central hole and ball joints (8) cooperates, the thimble (22) mounted in the cylinder (15) on the thimble hole, the return spring (13) and bushing sleeve small spring (14) after the (20) mounted on the drive shaft (1) and cylinder (15) between the pump body (17) and casing (12) between the variables associated with the screw pump Training - with oil pan (16) mounted on the cylinder (15) and pump (17 between); hole retainer (19) mounted on the cylinder (15) near the end of the oil pan (16); variable by variable housing body (2), the variable head (3), a small dial blocks (4 ), dial column (5), variable valve (6) and a large dial blocks (7), with the top screwed in the variable housing (2) variable valve (6), variable head (3) with variable case ( 2) Inter through bush (23) linked to a small dial blocks (4) mounted on the rear derailleur column (5) mounted in the variable valve (6), the lower dial column (5) is inserted in the large dial blocks (7) hole on the big dial block (4) with screws in the variable head (3), between the main body and the variables associated with screws, end drive shaft (1) through a bearing mounted on the pump (17), The other end by bearings mounted in the variable housing (2), the one-way thrust ball bearings (18) installed between the pump bearings and bushings (17) (20). Variable pump sales - crystal create a hydraulic (certified), variable pump from Jinan Jing Chong hydraulic machinery Limited. Jinan Jing Chong Hydraulic Machinery Co., Ltd. (www.jnjcyy.com) (www.jnjcyy.com) Shandong Jinan, mining machinery leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum meet customer needs. In the crystal to create a hydraulic leadership with the staff warmly welcome all inquiries negotiations to create the crystal to create a better future for the hydraulic.