CN103184990B - Oblique plunger type pure water hydraulic swash plate pump - Google Patents

Abstract

The invention relates to an inclined plunger type pure water hydraulic swash plate pump, which adopts a spherical flow distribution structure of a conical cylinder body. The plunger forms an included angle with the transmission shaft, and the plunger forms a conical layout relative to the transmission shaft. The centripetal force generated during work is beneficial to the return stroke of the plunger. The main shaft is connected with the tapered cylinder through the spline, and the plunger and the sliding shoe are matched through the ball joint. The disc spring is pressed between the ball joint and the conical cylinder to provide the return force of the plunger during the working process and realize the sealing of the sliding shoe pair and the distribution pair. The distribution plate adopts a spherical distribution structure, which is conducive to balancing the overturning moment generated by the conical cylinder and improving the self-positioning of the conical cylinder and the distribution plate; the structure of the conical cylinder and the spherical distribution plate makes the distribution window of the distribution plate The diameter of the circle is reduced to reduce the water suction flow rate and enhance the self-priming ability of the pump. The pump uses filtered fresh water or sea water as the working medium, which overcomes the problems of poor self-priming ability and difficult return stroke of existing pure water hydraulic plunger pumps, and has obvious technical advantages.

Description

Inclined plunger pure water hydraulic swash plate pump

technical field

The invention relates to an inclined plunger type pure water hydraulic swash plate pump, which can be used as a power element in a pure water hydraulic transmission system and belongs to the technical field of fluid transmission and control.

Background technique

Pure water hydraulic technology is a new technology that uses natural fresh water or sea water instead of mineral oil as the working medium of the hydraulic system. In recent years, based on the increasing emphasis on safety and sanitation, energy conservation, environmental protection and ocean development, the research on pure water hydraulic technology has become a frontier research topic in the international hydraulic industry. Compared with hydraulic transmission using other types of media, pure water hydraulic transmission has the following advantages:

(1) Environmentally friendly and pollution-free. Generally, the leaked water does not need to be recycled, and will not pollute the environment. It avoids the problem of incompatibility with the environment when using oil as the medium, and realizes the "green" of the transmission process.

(2) Good flame retardancy, non-combustible. Due to the physical and chemical properties of water, there is no need to worry about serious accidents such as fires after leakage.

(3) Low cost, convenient storage and transportation. Water resources are widely distributed and easy to use, so there is no need for special storage and transportation, which saves expenses and improves efficiency accordingly.

(4) The pure water hydraulic system has a simple structure and is easy to maintain.

The water hydraulic pump is the core of the pure water hydraulic transmission system. Currently, the most widely used water hydraulic pumps include centrifugal pumps, two-piston pumps and three-piston pumps. Centrifugal pumps have disadvantages such as low pressure and high noise, and cannot fully meet the pump source requirements of pure water hydraulic transmission systems; two-plunger pumps and three-plunger pumps have disadvantages such as small flow, large volume, and large vibration and noise, and cannot be widely used. Various pure water hydraulic transmission systems. The swash plate plunger pump and the inclined shaft plunger pump have the advantages of high pressure and large flow, small size, convenient maintenance, and can meet the requirements of noise and vibration, and have attracted the attention of scholars all over the world. Developed countries have developed relatively mature products and occupied a considerable part of the market.

The Danfoss series pumps in Denmark, the TWHC and Fenner series pumps in the UK generally adopt the swash plate type plate flow distribution structure, and have all been marketed. However, these types of pumps have too high requirements on the filtration accuracy of the working medium (generally ≤10um), and their anti-pollution ability and self-priming ability are poor.

Our country is still in the research and development stage in this technical field, and the prototypes developed are not mature enough to be commercialized yet. Chinese patent (CN 1554869A) discloses a pure water hydraulic axial plunger pump or motor with full water lubricated end face distribution. The pump adopts the outer bearing of the cylinder to support the tapered cylinder, and the plunger pair adopts gap seal, which is difficult to process. Poor anti-pollution ability.

Chinese patent (CN 102155370A) discloses a pure water hydraulic through-shaft spherical flow distribution axial plunger pump, which uses two front and rear sliding bearings to support the main shaft and a spherical flow distribution structure. Judging from the published structural diagram, the front and rear bearings are in a closed cavity, which cannot circulate with the water in the housing cavity, and the front and rear bearings cannot be effectively lubricated and cooled. In the working process of the pump, it will inevitably cause severe wear and failure of the front and rear bearings, and the practicability is not strong.

Chinese patent (CN 102141022A) discloses a double swash plate valve distribution axial plunger type water hydraulic shielded pump. When the pump works, the rotor drives the conical cylinder to rotate, and the distribution valve rotates in the conical cylinder. The rotation of the distribution pair is likely to cause insufficient water suction of the pump. Therefore, the self-priming ability of this kind of pump is poor, and the speed is difficult to increase.

Chinese patent (CN 102734109) discloses a kind of all-water lubricated valve distribution plunger water pump, the main shaft drives the swash plate to rotate when the pump is working, and is supported by roller bearings. When this kind of pump is working, the swash plate has a problem of dynamic unbalance, and the roller bearing is not suitable for the occasion of full water lubrication.

Contents of the invention

In order to overcome the disadvantages of the existing pure water hydraulic plunger pumps such as complex structure, poor self-priming ability, large fluid noise, and easy failure of sliding bearings, it provides high-pressure water with sufficient pressure and flow for the pure water hydraulic transmission system. The invention provides an inclined plunger type pure water hydraulic swash plate pump. Through reasonable structural design, the self-priming ability of the pure water hydraulic plunger pump is improved, the working conditions of key components are improved, and the utility model is very strong.

The present invention adopts the following technical means, an inclined plunger type pure water hydraulic swash plate pump, in which the front end cover 3, the housing 10, and the rear end cover 16 are connected as one; the main shaft 1 is connected with the tapered cylinder body 11 to form the main shaft- Tapered cylinder assembly; the front sliding bearing 28 is embedded in the front end cover 3 and connected to the main shaft 1; the rear support shaft 15 is in interference connection with the rear end cover 16, and the rear sliding bearing 12 is embedded in the inside of the tapered cylinder 11; the front sliding The bearing bushes of the bearing 28 and the rear sliding bearing 12 are provided with spiral water passage grooves 13; the main shaft 1 is provided with cross water passage holes B22 and radial water passage holes 25, and the rear support shaft is provided with cross water passage holes A14. The cover 3 is provided with an annular water channel 5 , an oblique water hole 4 and an axial water hole 27 , which connect the lubricating grooves of the front sliding bearing 28 and the rear sliding bearing 12 with the cavity of the housing 10 .

One end of the spherical hinge 8 cooperates with the inner circle of the return disk 7 to form a spherical hinge pair. Several holes are evenly distributed on the return disk 7, and the same number of sliding shoes 23 are attached to the swash plate 6; the other end of the spherical hinge 8 is connected to the tapered cylinder. The bodies 11 are connected by disc springs 24 .

The cylinder holes 19 and the center line of the main shaft 1 are evenly distributed at an angle, and a cylinder liner 20 is press-fitted into each cylinder hole 19, and the ball head of the plunger 21 and the ball socket of the sliding shoe 23 form a plunger assembly. The plunger assembly constitutes a plunger pair; the plunger 21 communicates with the waist-shaped groove 17.2 on the distribution plate 17 through the corresponding cylinder hole 19; the inner spherical surface 11.1 at the bottom of the conical cylinder and the outer spherical surface 17.1 of the distribution plate form a spherical flow distribution pair; the flow distribution The disk 17 is installed on the rear end cover 16 by screws 18, and an O-ring is assembled on the reverse side to realize sealing.

In the present invention, the included angle between the cylinder hole 19 and the centerline of the main shaft 1 is 1°-15°.

The realization of the bearing pair of the present invention: the front sliding bearing 28 and the rear sliding bearing 12 are all made of wear-resistant materials such as polymer composite materials or ceramics, and then they are interference-fitted on the front end cover 3 and the tapered cylinder body 11, or by injection molding process, the polymer composite material is directly injected into the front end cover 3 and the conical cylinder 11; the bearing bush is provided with a spiral water channel 13, and the groove passes through the annular water channel 5 opened by the front end cover 3, and the oblique water channel The hole 4 and the axial water hole 27 communicate with the cavity of the housing 10 . The fluid inside the bearing can form a circulating flow with the fluid in the casing cavity, fully realizing the lubrication and cooling of the bearing.

The implementation of the plunger pair of the present invention: the cylinder liner 20 is made of corrosion-resistant alloy or ceramic material, and the cylinder liner 20 made of corrosion-resistant alloy is heat-treated to improve its hardness and wear resistance, and its inner circle is subjected to surface strengthening treatment The surface of the plunger base 21.1 is inlaid with a plunger sleeve 21.2 made of polymer composite material, and is fixed by a compression nut 21.4, and the lock nut is axially limited by a pin 21.5; the plunger hole of the plunger 21 passes through The excess pressure enters the plugging rod 21.3 to reduce the volume of the plunger cavity.

Implementation of the shoe pair in the present invention: the shoe 23 includes a metal substrate provided with a plurality of threaded holes, and a layer of polymer composite material is injection-molded on the substrate for the friction surface, and constitutes a shoe pair with the swash plate 6 . The swash plate 6 is made of corrosion-resistant alloy material, and the hardness and wear resistance of the friction slope are improved through heat treatment and surface modification.

The realization of the distribution pair of the present invention: the distribution plate 17 includes a metal base with a plurality of threaded holes, a layer of polymer composite material is injected on the base, and the front of the distribution plate is processed into an outer spherical surface 17.1 for friction surface; The inner spherical surface 11.1 at the bottom of the cylinder body is heat-treated and surface-modified to improve its hardness and wear resistance, and forms a flow distribution pair with the outer spherical surface 17.1 of the distribution plate.

The polymer composite material used in the present invention is PEEK or other wear-resistant engineering plastics, the material of the plugging rod 21.3 is nylon or other engineering plastics, and the corrosion-resistant alloy is stainless steel or titanium alloy.

The present invention can obtain following beneficial effect:

1. The bearing pair adopts a spiral lubricating groove structure, and the fluid in the lubricating groove and the fluid in the pump body form a cycle, which is beneficial to the lubrication and cooling of the bearing, and improves the service life and working reliability of the bearing.

2. The semi-shaft structure is adopted, the front bearing supports the main shaft, and the rear inner bearing supports the tapered cylinder body. The bearing layout is reasonable, which makes the PV value of the front and rear bearings evenly distributed, and avoids serious wear of the bearings due to uneven force. At the same time, the rear sliding bearing can balance the overturning moment of the valve plate, which improves the working stability of the pump.

3. The plunger is arranged in a conical shape relative to the drive shaft. The centripetal force generated during work is beneficial to the return stroke of the plunger. The conical cylinder reduces the pitch circle diameter of the distribution window of the distribution plate, reduces the water absorption flow rate, enhances the self-priming capacity, and reduces Fluid noise.

4. The spherical distribution structure is adopted, which is beneficial to balance the overturning moment generated by the conical cylinder during work, improves the self-positioning of the conical cylinder and the distribution plate, and cancels the floating liner of the existing swash plate hydraulic plunger pump The structure reduces the difficulty of processing and makes the structure of the pump more compact.

5. Disc springs are used to provide the pre-compression force of the sliding shoe pair and the distribution pair and the return force of the plunger, which overcomes the shortcoming of the cylindrical coil springs used in other hydraulic plunger pumps that are prone to failure, and enhances the work of the pump return spring longevity and reliability.

6. The main friction pairs are all made of polymer composite materials and matched with corrosion-resistant alloys or ceramics, which can meet the requirements of pure water hydraulic pumps for friction, wear and corrosion resistance of key friction pairs.

7. A number of small threaded holes are opened on the metal substrate of the sliding shoe and the distribution plate, so that the injected polymer composite material can be embedded in the threaded small holes, and the connection between the injection layer and the metal substrate is enhanced.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic diagram of the structure of a tapered cylinder;

Figure 3 is a schematic diagram of the structure of the distribution plate;

Figure 4 is a schematic structural view of the plunger pair.

In the figure: 1 main shaft, 2 shaft seal, 3 front end cover, 4 oblique water hole, 5 annular water channel, 6 swash plate, 7 return plate, 8 spherical hinge, 9 exhaust screw plug, 10 shell, 11 cone shaped cylinder, 11.1 inner spherical surface, 12 rear sliding bearing, 13 spiral water channel, 14 cross channel A, 15 rear support shaft, 16 rear end cover, 17 distribution plate, 17.1 outer spherical surface, 17.2 waist groove, 16.3 High-pressure waist groove, 18 screws, 19 cylinder bore, 20 cylinder liner, 21 plunger, 21.1 plunger base, 21.2 plunger sleeve, 21.3 plugging rod, 21.4 lock nut, 22 cross water hole B, 23 sliding shoe, 24 disk springs, 25 radial water holes, 26 positioning pins, 27 axial water holes, 28 front sliding bearings.

Detailed ways

The implementation of the present invention will be described in more detail below with reference to the accompanying drawings 1 to 4 in some embodiments of the present invention. Obviously, the described embodiments are only a part of all embodiments of the present invention. Other embodiments obtained directly or associatively from the disclosure of the present invention by persons of ordinary skill in the art without creative work, all belong to the protection scope of the present invention.

An embodiment of the present invention provides an inclined plunger type pure water hydraulic swash plate pump. As shown in Figure 1, the front end cover 3, the housing 10, and the rear end cover 16 are connected as one; the main shaft 1 is connected with the tapered cylinder 11 to form a main shaft-tapered cylinder assembly; the front sliding bearing 28 is embedded in the front end cover 3 In the middle, it is connected with the main shaft 1; the rear support shaft 15 is in interference connection with the rear end cover 16, and the rear sliding bearing 12 is embedded in the inside of the tapered cylinder body 11; Groove 13; main shaft 1 is provided with cross water hole B 22 and radial water hole 25, rear support shaft is provided with cross water hole A 14, front end cover 3 is provided with annular water channel 5, oblique water channel The hole 4 and the axial water hole 27 communicate the lubricating grooves of the front sliding bearing 28 and the rear sliding bearing 12 with the cavity of the housing 10 . A screw plug 9 is installed on the casing 10, which is opened when the pump is not working to discharge air and prevent cavitation, and the shaft seal 2 is used to seal the end face of the main shaft 1.

One end of the spherical hinge 8 cooperates with the inner circle of the return disk 7 to form a spherical hinge pair. Several holes are evenly distributed on the return disk 7, and the same number of sliding shoes 23 are attached to the swash plate 6; the other end of the spherical hinge 8 is connected to the tapered cylinder. The bodies 11 are connected by disc springs 24 .

The cylinder holes 19 and the center line of the main shaft 1 are evenly distributed at an angle, and a cylinder liner 20 is press-fitted into each cylinder hole 19, and the ball head of the plunger 21 and the ball socket of the sliding shoe 23 form a plunger assembly. The plunger assembly constitutes a plunger pair; the plunger 21 communicates with the waist-shaped groove 17.2 on the distribution plate 17 through the corresponding cylinder hole 19; the inner spherical surface 11.1 at the bottom of the conical cylinder and the outer spherical surface 17.1 of the distribution plate form a spherical flow distribution pair; the flow distribution The disk 17 is installed on the rear end cover 16 by screws 18, and an O-ring is assembled on the reverse side to realize sealing.

In the inclined plunger type pure water hydraulic swash plate pump, the included angle between the cylinder bore 19 and the centerline of the main shaft 1 is 1°-15°.

Inclined plunger type pure water hydraulic swash plate pump, its suction and drainage, lubrication and cooling work process is as follows: before the pump starts, the working water flows into the cavity of the casing 10 from the water inlet of the pump, and the low-pressure water in the casing cavity is respectively pumped by the main shaft The cross water hole B 22 on the top, the annular water groove 5 on the front end cover 3, the axial water hole 27, and the oblique water hole 4 enter the spiral water groove 13 of the rear sliding bearing 12 and the front sliding bearing 28 , and make the cavity of the whole pump body evenly filled with working medium water; when the pump is working, the water in the casing 10 passes through the waist-shaped groove 17.2 on the distribution plate 17, and is sucked into the plunger cavity by the plunger 21, when the plunger moves When reaching the top dead center of the swash plate, the water absorption ends; after the plunger 21 turns over the top dead center, the drainage process starts. Now the low-pressure water in the pump chamber is discharged from the pump body through the waist-shaped groove 17.2 of the distribution plate by the plunger 21 on one side, and is continuously replenished from the water inlet of the pump on the one hand. The flow circulation effect of water in the pump chamber is formed, and the heat generated by each friction pair is taken away, which is beneficial to the lubrication and cooling of the friction pair. Since the plunger 21 has a conical layout relative to the main shaft 1, the centripetal force generated during work is beneficial to the return stroke of the plunger 21. The conical cylinder 11 reduces the pitch circle diameter of the flow distribution window of the flow distribution plate 17, reduces the water absorption flow rate, and enhances self-improvement. Suction capacity, reduce fluid noise.

The implementation of the plunger pair of the present invention: as shown in Figure 4, the plunger base 21.1 is made of corrosion-resistant alloy, the surface is inlaid with a plunger sleeve 21.2 made of polymer composite material, and the lock nut 21.4 is used to fix the lock tight to ensure that the plunger sleeve 21.2 does not fall off during the operation of the pump; the lock nut is axially limited by the pin 21.5; the plugging rod 21.3 is pressed into the plunger hole of the plunger 21 to reduce the volume. The cylinder liner 20 matched with the plunger 21 is made of corrosion-resistant alloy or ceramic material, and its hardness and wear resistance are improved through heat treatment and surface strengthening treatment of the inner circle.

The realization of the bearing pair of the present invention: the front sliding bearing 28 and the rear sliding bearing 12 are all made of wear-resistant materials such as polymer composite materials or ceramics, and then they are interference-fitted on the front end cover 3 and the tapered cylinder body 11, or by injection molding process, the polymer composite material is directly injected into the front end cover 3 and the conical cylinder 11; the bearing bush is provided with a spiral water channel 13, and the groove passes through the annular water channel 5 opened by the front end cover 3, and the oblique water channel The hole 4 and the axial water hole 27 communicate with the cavity of the housing 10 . The fluid inside the bearing can form a circulating flow with the fluid in the casing cavity, and the sliding bearing can be fully lubricated and cooled.

The realization method of the automatic compensation of the end surface friction pair of the present invention: the two ends of the disc spring 24 are in contact with the ball joint 8 and the tapered cylinder 11 respectively. Under the action of the spring force, the conical cylinder 11 can produce a small amount of floating in the axial direction. When the conical cylinder is subjected to the overturning moment generated by the swash plate 6 and slightly tilted in the axial direction, due to the inner spherical surface at the bottom of the conical cylinder The structure of 11.1 and the outer spherical surface of the distribution plate 17.1 compensates the inclination caused by the axial partial load under the action of the spring force, ensuring that the conical cylinder 11 is always close to the distribution plate 17, and automatically compensates the conical cylinder 11 and the distribution plate 17 to reduce the amount of leakage; when the wear amount of the end face of the sliding shoe 23 and the distribution plate 17 increases, under the action of the disc spring 24, the sliding shoe 23 and the swash plate 6, the distribution plate 17 and the tapered cylinder Body 11 fits tightly again, compensating for wear.

The realization of the distribution pair of the present invention: the distribution plate 17 includes a metal base with a plurality of threaded holes, a layer of polymer composite material is injected on the base, and the front of the distribution plate is processed into an outer spherical surface 17.1 for friction surface; The inner spherical surface 11.1 at the bottom of the cylinder is heat-treated and surface modified (nitriding, laser cladding ceramics, etc.) to improve its hardness and wear resistance, and forms a distribution pair with the outer spherical surface 17.1 of the distribution plate.

The sliding shoe 23, the front sliding bearing 28 and the rear sliding bearing 12 of the present invention can all adopt the technology of injecting a layer of polymer composite material on the metal substrate, and a plurality of threaded holes are all opened on the metal substrate, so that the polymer after injection molding The composite material is embedded in the small threaded hole, which enhances the bonding force between the injection molding layer and the metal matrix.

The polymer composite material used in the present invention is PEEK or other wear-resistant engineering plastics, the material of the plugging rod 21.3 is nylon or other engineering plastics, and the corrosion-resistant alloy is stainless steel or titanium alloy.

Claims (10)

1. oblique plunger type pure water hydraulic swash plate pump, wherein front cover (3), housing (10), rear end cover (16) connect as one; Main shaft (1) is connected with conical cylinder (11), forms main shaft-conical cylinder assembly; Front slide bearing (28) is embedded in front cover (3), is connected with main shaft (1); Rear support axle (15) is connected with rear end cover (16) interference, and it is inner that rear sliding bearing (12) is embedded in conical cylinder (11), is connected with conical cylinder (11); The bearing shell of front slide bearing (28) and rear sliding bearing (12) is all offered helical water-through groove (13); Main shaft (1) is provided with cross water port B (22) and radial water port (25), rear support axle (15) is provided with cross water port A (14), front cover (3) offers annular water-flowing trough (5), oblique water port (4) and axial water port (27), the lubricating channels of front slide bearing (28), rear sliding bearing (12) is communicated with the cavity of housing (10);

Ball pivot (8) one end coordinates with return plate (7) inner circle and forms typed ball bearing pair, and (7) are uniformly distributed several holes to return plate, are adjacent on swash plate (6) by the piston shoes (23) of identical number; Ball pivot (8) the other end is connected by belleville spring (24) with conical cylinder (11);

Cylinder holes (19) has angle with the center line of main shaft (1) and is uniformly distributed, force fit cylinder sleeve (20) in each cylinder holes (19), plunger (21) bulb and piston shoes (23) ball-and-socket form plunger assembly, and cylinder sleeve (20) and plunger assembly form trunk piston set; Plunger (21) is communicated with the kidney slot (17.2) on thrust plate (17) by corresponding cylinder holes (19); Conical cylinder bottom inner ball surface (11.1) and thrust plate outer spherical surface (17.1) form spherical port plate; Thrust plate (17) is installed on rear end cover (16) by screw (18), and reverse side assembling O RunddichtringO realizes sealing.

2. oblique plunger type pure water hydraulic swash plate pump according to claim 1, is characterized in that: described cylinder holes (19) is 1 ° ~ 15 ° with the angle of main shaft (1) center line.

3. oblique plunger type pure water hydraulic swash plate pump according to claim 1, it is characterized in that: described front slide bearing (28), rear sliding bearing (12) make rear elastic conjunction in front cover (3), conical cylinder (11) by polymer composite or pottery, or employing Shooting Technique, direct by polymer composite molding and forming in front cover (3), conical cylinder (11); Bearing shell is all offered helical water-through groove (13), groove offered by front cover (3) annular water-flowing trough (5), oblique water port (4) and axial water port (27), communicate with the cavity of housing (10).

4. oblique plunger type pure water hydraulic swash plate pump according to claim 1, it is characterized in that: described cylinder sleeve (20) adopts corrosion resistant alloy or stupalith to make, the cylinder sleeve (20) that corrosion resistant alloy is made improves its hardness and wear resistance through Overheating Treatment, and carries out surface Hardening Treatment to its inner circle; The plunger bushing (21.2) that plunger matrix (21.1) surface inserting one is made up of polymer composite, and by locking nut (21.4) fixing and locking, locking nut carries out axial limiting by pin (21.5); Force fit stemming rod (21.3) in the plunger hole of plunger (21), reduces the volume of plunger cavity.

5. oblique plunger type pure water hydraulic swash plate pump according to claim 1, it is characterized in that: described piston shoes (23) comprise the metallic matrix having offered multiple tapped hole, injection moulding one deck polymer composite layer on matrix, for rubbing surface, form Slipper coupling with swash plate (6); Swash plate (6) adopts corrosion resistant alloy material to make, and improves hardness and the wear resistance on its inclined-plane by heat treatment and surface modification treatment.

6. oblique plunger type pure water hydraulic swash plate pump according to claim 1, it is characterized in that: described thrust plate (17) comprises the metallic matrix having offered multiple tapped hole, injection moulding one deck polymer composite layer on matrix, is processed into outer spherical surface (17.1) for rubbing surface by thrust plate front; Its hardness and wear resistance are improved by heat treatment and surface modification treatment in conical cylinder bottom inner ball surface (11.1), form Port Plate Pair with thrust plate outer spherical surface (17.1).

7. oblique plunger type pure water hydraulic swash plate pump according to claim 3, is characterized in that: described polymer composite is PEEK or other wear-resisting level engineering plastics.

8. oblique plunger type pure water hydraulic swash plate pump according to claim 4, is characterized in that: stemming rod (21.3) material is nylon or other engineering plastics.

9. oblique plunger type pure water hydraulic swash plate pump according to claim 4, is characterized in that: the corrosion resistant alloy of cylinder sleeve (20) is stainless steel or titanium alloy material.

10. oblique plunger type pure water hydraulic swash plate pump according to claim 5, is characterized in that: the corrosion resistant alloy of swash plate (6) is stainless steel or titanium alloy material.