JP5616384B2 - Oblique shaft type hydraulic rotating machine and manufacturing method of oblique axis type hydraulic rotating machine - Google Patents

Description

  The present invention relates to a slanted shaft type hydraulic rotating machine such as a hydraulic pump and a hydraulic motor, and a manufacturing method thereof.

  In a hydraulic rotating machine represented by a hydraulic pump and a hydraulic motor, there are those described in Patent Document 1 and Patent Document 2 in order to improve sliding characteristics between a cylinder block and a piston combined with the cylinder block. is there.

  In Patent Document 1, the cylinder inner surface of the cylinder block is cast iron material as it is or nitrided, and the piston is made of steel that can be nitrided. The piston is tempered to increase the base hardness and then nitrided, and the outer peripheral surface of the piston Among the hardened surface layers, it is described that a high hardness layer is removed and a hardness layer higher than the base hardness after tempering is left.

  Patent Document 2 describes that a cylindrical molded body made of a copper-based material is joined by sintering in a piston hole of a cylinder block.

JP-A-6-159230 JP-A-10-196552

The hydraulic rotating machine described above has many sliding portions in addition to the sliding portions between the cylinder bore and the piston. The sliding surfaces of these sliding parts may be seized or have local anomalies due to the effect of the lubrication oil film running out due to high sliding surface pressure and the instability of the sliding contact state due to fluctuations in control hydraulic pressure. There is a risk of wear. For this reason, most of the sliding parts constituting the sliding part are made of steel.
Among them, spheroidal graphite cast iron (FCD material) that is inexpensive and has high sliding performance among steel materials, and in particular, among FCD materials, those having a structural structure of ferrite or pearlite, or their coexisting structure are often used.

  Here, the sliding parts in the hydraulic rotary machine of the hydraulic pump or hydraulic motor slide as the size and the material cost increase as the usage conditions of the hydraulic rotary machine become higher and flow rate increases. Of the members, a member having a large size is often formed of an FCD material and a counterpart member thereof is formed of a steel material.

  For example, in a slant axis type hydraulic rotating machine, the sliding area of the sliding part between the valve plate and the head casing provided on the back of the cylinder block is larger than the sliding area of the cylinder block and the piston. The valve plate is made of steel and the head casing is made of FCD.

However, the FCD material has a drawback that the surface hardness is lower than that of the steel material.
Therefore, in order to compensate for this drawback, in Patent Document 1, the surface area of the sliding surface is cured by forming a nitrogen diffusion layer by performing a nitriding heat treatment on the FCD material and the steel material constituting the sliding surface, Furthermore, by forming a hard nitrogen compound layer thereon, wear resistance and seizure resistance against sliding loads are ensured. Further, the nitrogen compound layer is processed and removed from the sliding surface of the FCD material.

  Further, in Patent Document 2, the sliding surface of the steel material part avoids seizure phenomenon in high surface pressure sliding by depositing or sintering a sliding copper alloy on the surface after removing the nitrogen compound layer. ing.

  When a member on one side in the sliding portion having such a large sliding area is an FCD material, and the FCD material is processed to form a sliding surface, a hole in which the carbon of the FCD material has dropped due to the processing is formed on the sliding surface. The FCD material that is exposed as a hole or plastically flows when the peripheral part is processed covers the exposed hole.

Further, when Patent Document 1 is applied to the sliding portion described above, even if the nitriding heat treatment is performed, the hole from which the carbon has dropped is completely filled in the portion where the hole from which the carbon has dropped is completely exposed. Thus, since the nitrogen compound layer is not formed, surface defects exist on the sliding surface of the FCD material. Therefore, when sliding with the mating member, stress concentrates on the surface defect end or the end of the mating sliding surface is caught, causing delamination failure at the end of the nitrogen compound layer, and hard nitrogen The peeled piece of the compound is present between the sliding surfaces. Accordingly, there is a risk that abnormal wear or seizure occurs on the sliding surface when sliding is performed at a high surface pressure.
In addition, in a place where the pores are covered with the plastic flow structure, a nitrogen compound layer is formed on the plastic flow structure. A defect is formed. For this reason, when a sliding load is applied by the mating surface, the surface defect peels and breaks, causing abnormal wear and seizure of the sliding surface.

  Moreover, when patent document 2 is applied to the sliding part mentioned above, the copper alloy which forms the sliding surface will become expensive, and generally copper alloy composition and temperature management are very difficult in the copper alloy film forming process. Therefore, there is a problem that the manufacturing difficulty is high.

  For this reason, there is no effective measure for the sliding portion having a large sliding area in the oblique axis type hydraulic rotating machine, and there is an urgent need for improvement.

  The present invention includes a sliding portion that realizes a more stable sliding state in a slant shaft type hydraulic rotating machine having a portion with a large sliding surface area between members made of spheroidal graphite cast iron and steel. Another object of the present invention is to provide a slant shaft type hydraulic rotating machine and a manufacturing method thereof.

In order to achieve the above object, the first invention is a sliding portion for slidingly contacting one sliding surface of one member that is a steel material and the other sliding surface of another member that is a spheroidal graphite cast iron material. A slanted axis type hydraulic rotating machine comprising a nitriding surface treatment on a sliding surface, and after removing a nitrogen compound layer formed from at least one of lead, tin and copper The non-ferrous soft metal coating is formed in the one sliding surface on which the non-ferrous soft metal coating is formed, and in the holes from which carbon, which is a surface defect present in the nitrogen compound layer formed by nitriding surface treatment on the sliding surface, is dropped. And the other sliding surface that has been intruded and filled.

  According to the first aspect of the present invention, a part of the non-ferrous soft metal coating formed on the surface of the sliding surface of one member made of steel that is the sliding counterpart surface of another member made of FCD material is FCD. The surface defects (openings and crack gaps) existing on the surface of other members made of a material are pushed in by a sliding load, filling internal vacancies (holes from which carbon has dropped), and surface defects Landfill. Therefore, the effect of smoothing the sliding surface and the effect of strongly suppressing peeling fracture by supporting an unstable plastic flow structure from the inside can be obtained. As a result, even if the sliding surface area made of steel and spheroidal graphite cast iron material is large, it has a more stable sliding part than before, and the life of the slanted shaft type hydraulic rotating machine is extended. can do.

In order to achieve the above object, the second invention is a sliding device for slidingly contacting one sliding surface of one member that is a steel material and the other sliding surface of another member that is a spheroidal graphite cast iron material. A manufacturing method of a slant axis type hydraulic rotating machine having a moving part, wherein the one member is subjected to nitriding surface treatment, and then formed on the surface of one sliding surface of the one member Nitrogen compound removal is removed to expose a nitrogen diffusion layer, and a non-ferrous soft metal film made of at least one metal selected from the group consisting of lead, tin, and copper is formed on the exposed surface of the nitrogen diffusion layer. A sliding surface is formed, and a nitriding surface treatment is performed on the other member to form a nitrogen compound layer to form the other sliding surface of the other member.

  According to the second invention, a part of the non-ferrous soft metal coating formed on the sliding mating surface is against surface defects (openings and crack gaps) existing on the surface of the spheroidal graphite cast iron material. It is pushed in by a sliding load and fills internal vacancies (holes from which carbon has dropped) to fill surface defects. Therefore, the effect of strongly suppressing delamination failure can be obtained by smoothing the sliding surface and supporting an unstable plastic flow structure from the inside. Thereby, even if the area of the sliding surface which consists of steel materials and a spheroidal graphite cast iron material is large, a more stable sliding part can be formed compared with the past.

  In a third aspect based on the second aspect, the non-ferrous soft metal coating is formed by plating.

  According to the third aspect of the present invention, it is possible to efficiently form a film having a uniform thickness even on a wide film formation target surface.

  According to a fourth invention, in the second invention, the non-ferrous soft metal coating is caused to inject or project collision of fine particles made of non-ferrous soft metal material at a high speed against the formation target portion of the non-ferrous soft metal coating. It is formed by depositing.

  According to the fourth aspect of the present invention, it is possible to form a film even with respect to the deep hole shape or the portion where the plating solution has poor throwing power. In addition, it can be formed by selectively changing the film thickness with respect to a specific region in the sliding surface, and even when the sliding surface pressure and sliding speed are different in the sliding surface, The function can be optimized by changing the film thickness according to the speed region.

  Further, a fifth invention is the method according to the second invention, wherein the non-ferrous soft metal coating is formed on the site where the non-ferrous soft metal coating is to be formed, and then the top of the phosphate coating is formed. It is formed by chemically substituting the surface and the nonferrous soft metal component.

  According to the fifth aspect of the present invention, the adhesion of the coating to the sliding surface of the steel material component is enhanced, the sudden loss of non-ferrous soft metal coating due to abnormal coating formation can be greatly reduced, and the surface defect filling effect can be achieved. It becomes possible to exhibit stably.

  According to the oblique axis type hydraulic rotating machine of the present invention, the sliding performance of the sliding surface having the surface defect can be stabilized, and the sliding portion that realizes a more stable sliding state is provided. A slanted-axis hydraulic rotating machine is provided, which makes it possible to extend the life of the slanted-axis hydraulic rotating machine.

  According to the manufacturing method of a slant axis type hydraulic rotating machine of the present invention, a slant axis type hydraulic rotating machine having a sliding portion that realizes a more stable sliding state and capable of extending the service life is manufactured. Can do.

It is a longitudinal cross-sectional view of 1st Embodiment of the slant axis | shaft type hydraulic rotating machine of this invention. FIG. 2 is a cross-sectional view showing a sliding portion of a valve plate and a head casing constituting the first embodiment of the oblique-shaft hydraulic rotating machine of the present invention shown in FIG. 1, wherein FIG. 2 (a) is the valve plate and the head casing. FIG. 2B is an enlarged sectional view showing a portion A of FIG. 2A. It is a longitudinal cross-sectional view which shows the manufacturing process of the valve plate which comprises 1st Embodiment of the slant axis type hydraulic rotating machine of this invention. It is a longitudinal cross-sectional view which shows the manufacturing process of the valve plate which comprises 1st Embodiment of the slant axis type hydraulic rotating machine of this invention. It is a longitudinal cross-sectional view which shows the manufacturing process of the valve plate which comprises 1st Embodiment of the slant axis type hydraulic rotating machine of this invention. FIG. 6 is a cross-sectional view showing a manufacturing process of the head casing constituting the first embodiment of the oblique-axis hydraulic rotating machine of the present invention, and FIG. 6A is a longitudinal cross-sectional view showing a part of the head casing in cross section. FIG. 6B is an enlarged cross-sectional view of a portion A in FIG. It is a longitudinal cross-sectional view which shows the manufacturing process of the valve plate which comprises 2nd Embodiment of the slant axis type hydraulic rotating machine of this invention. FIG. 8A is a cross-sectional view showing a manufacturing process of a valve plate constituting a third embodiment of the oblique-axis hydraulic rotating machine of the present invention, and FIG. 8A is a vertical cross-sectional view showing a part of the valve plate in cross section. FIG. 8B is an enlarged cross-sectional view of a portion A in FIG. FIG. 9A is a cross-sectional view showing a manufacturing process of a valve plate constituting a third embodiment of the oblique-axis hydraulic rotating machine of the present invention, and FIG. 9A is a longitudinal cross-sectional view showing a part of the valve plate in cross section. FIG. 9B is an enlarged cross-sectional view of a portion A of FIG.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a slanted-axis hydraulic rotating machine and a manufacturing method thereof according to the present invention will be described below with reference to the drawings.

<First Embodiment>
A first embodiment of an oblique axis hydraulic rotating machine and a manufacturing method thereof according to the present invention will be described with reference to FIGS. 1 to 6, an example in which the present invention is applied to a variable displacement oblique shaft type axial piston pump as an oblique shaft type hydraulic rotating machine will be described.

  In FIG. 1, a variable displacement oblique axis type axial piston pump 1 as an oblique axis type hydraulic rotating machine includes a casing 2, a valve plate 3, a rotating shaft 4, a cylinder block 5, a piston 6, a connecting rod 7, and a drive disk 8. The center shaft 9, the tilting mechanism 10, and the regulator 11 are included.

  The casing 2 is made of a spheroidal graphite cast iron-based member, and one end side in the axial direction is a bearing portion. A cylindrical casing body 12 having an upper opening 12 </ b> A formed on the upper side of the peripheral body portion and a head casing 13 made of a spheroidal graphite cast iron material that closes the other end side of the casing body 12. The head casing 13 is provided with a concavely curved sliding contact surface 13A on which a later-described valve plate 3 is slidably contacted. The head casing 13 is provided with a suction passage for sucking hydraulic oil in a tank 14 described later and a discharge passage 13B for discharging pressure oil described later to the outside.

  The rotating shaft 4 is rotatably provided on one side in the axial direction in the casing body 12.

  The cylinder block 5 is rotatably provided integrally with the rotary shaft 4 in the casing body 12, is formed in a cylindrical shape with a steel material, and is slidably in contact with the valve plate 3. The cylinder block 5 is provided with a plurality of cylinders 15 (only two are shown) in the axial direction.

  The piston 6 is inserted into each cylinder 15 of the cylinder block 5 so as to be able to reciprocate. The protruding end side of the piston 6 is swingably supported by a drive disk 8 formed at the tip of the rotating shaft 4 by a connecting rod 7.

  The valve plate 3 is a member made of a steel material provided in sliding contact with the head casing 13 and the cylinder block 5. One end surface of the valve plate 3 is a slidable contact surface 3A that slidably contacts the slidable contact surface 5A of the cylinder block 5, and the other end surface is a convex curved shape that slidably contacts the slidable contact surface 13A of the head casing 13. This is a sliding contact surface 3B. A pair of supply / discharge ports (not shown) that intermittently communicate with the suction passage and the discharge passage 13B of the head casing 13 when the cylinder block 5 rotates are provided. A through hole 3C is formed on the center side of the valve plate 3, and a center shaft 9 and a swing pin 16 described later are inserted into the through hole 3C from both sides.

  The center shaft 9 supports the cylinder block 5 between the drive disk 8 and the valve plate 3. The center shaft 9 extends through the center of the cylinder block 5, one end side thereof is supported so as to be swingable with respect to the drive disk 8, and the other end side slides in the through hole 3 </ b> C of the valve plate 3. The cylinder block 5 is centered with respect to the valve plate 3.

  The tilting mechanism 10 is inserted into a stepped piston sliding hole 17 formed in the head casing 13 and slidably inserted in the piston sliding hole 17 in the directions indicated by arrows A and B in FIG. A stepped servo piston 18 defining hydraulic chambers 17A and 17B in the piston sliding hole 17 and a swing pin 16 provided in the servo piston 18 and inserted into the through hole 3C of the valve plate 3. Composed. The tilt mechanism 10 tilts the valve plate 3 along the sliding contact surface 13 </ b> A of the head casing 13.

  The regulator 11 is provided in the upper opening 12 </ b> A of the casing body 12, and includes a sleeve 19, a spool valve 20, a feedback link 21, and the like, and is configured as a capacity control valve of the oblique shaft type hydraulic rotating machine 1. In the regulator 11, the spool valve 20 slides and displaces in the sleeve 19 in accordance with the discharge pressure of the slant shaft type hydraulic rotating machine 1, whereby the tilt control pressure from the pilot pump 22 is supplied to the hydraulic chamber 17A. 17B, the servo piston 18 is slid and displaced, and the valve plate 3 is tilted along the sliding contact surface 13A of the head casing 13. When the valve plate 3 is tilted, the sleeve 19 is slid in the same direction as the spool valve 20 by the feedback link 21, and the regulator 11 is feedback-controlled.

Next, referring to FIG. 2, the structure of the sliding portion between the valve plate 3 and the head casing 13 constituting the first embodiment of the oblique-axis hydraulic rotating machine of the present invention will be described.
FIG. 2 is a cross-sectional view showing a sliding portion of the valve plate and the head casing constituting the first embodiment of the oblique-axis hydraulic rotating machine of the present invention shown in FIG. 1, and FIG. FIG. 2B is an enlarged cross-sectional view showing a portion A of FIG. 2A. FIG. 2B is a vertical cross-sectional view showing a part of the plate and the head casing.

As shown in FIG. 2 (a), the sliding portion between the valve plate 3 and the head casing 13 in the oblique-axis hydraulic rotating machine 1 of the present embodiment has a sliding surface on the valve plate 3 side of the steel material 30. The sliding surface 3B on which the non-ferrous soft metal coating 31 is formed after the nitrogen compound layer formed by nitriding surface treatment is processed and removed, and the sliding surface on the head casing 13 side are nitrided into the spheroidal graphite cast iron material 40. And a sliding surface 13A on which a nitrogen compound layer 42 is formed by performing a surface treatment.
Then, as shown in FIG. 2B, on the sliding surface 13A of the head casing 13 made of the nonferrous soft metal coating 31 formed on the sliding surface 3B of the valve plate 3 and the spheroidal graphite cast iron material 40. When the formed nitrogen compound layer 42 slides, a part of the non-ferrous soft metal coating 31 is allowed to enter from the openings or crack gaps of the surface defects 41a and 41b existing on the surface of the sliding surface 13A. As a result, the carbon existing immediately under the surface defect is adhered and filled into the hole 45 from which the carbon has fallen to smooth the sliding surface 13A of the head casing 13, and the plastic fluid structure 44 is supported by the non-ferrous soft metal that has been adhered and filled. In this structure, the plastic flow structure 44 having a nitrogen compound layer is prevented from peeling off, and the sliding state of both sliding surfaces 3B and 13A is stabilized and the surface defects 41a and 41b are stabilized.

  Here, the non-ferrous soft metal coating 31 in the present invention is a layer made of a metal which is an element different from iron and soft in hardness, and is made of, for example, at least one kind of metal among lead, tin, and copper. Become. The nitrogen compound layers 32 and 42 are layers made of a high hardness nitrogen compound formed on the outermost surface of the steel material or spheroidal graphite cast iron material when nitriding is performed. Further, the nitrogen diffusion layers 33 and 43 are formed by diffusing nitrogen formed immediately below the nitrogen compound layer formed on the outermost surface when nitriding is performed on a steel material or a spheroidal graphite cast iron material. It is a layer that penetrates into steel or spheroidal graphite cast iron.

  Next, the manufacturing method of one embodiment of the oblique axis type hydraulic rotating machine of the present invention configured as described above will be described with reference to FIGS. FIG. 3 is a longitudinal sectional view showing a manufacturing process of the valve plate constituting the first embodiment of the oblique-axis hydraulic rotary machine of the present invention, and FIG. 4 is a first view of the oblique-axis hydraulic rotary machine of the present invention. FIG. 5 is a longitudinal sectional view showing a manufacturing process of the valve plate constituting the first embodiment of the oblique axis hydraulic rotating machine of the present invention. 6 and 6 are cross-sectional views showing the manufacturing process of the head casing constituting the first embodiment of the oblique-axis hydraulic rotary machine of the present invention. FIG. 6A is a cross-sectional view of a part of the head casing. FIG. 6B is an enlarged sectional view of a portion A in FIG. 6A.

First, the outer shape of the valve plate 3 is produced from the steel material 30.
Thereafter, a nitriding heat treatment is applied to the outer shape of the manufactured valve plate 3 as a nitriding surface treatment. By this nitriding heat treatment, as shown in FIG. 3, a nitrogen diffusion layer 33 and a nitrogen compound layer 32 are formed on the surface layer of the sliding surface 3B of the valve plate 3, thereby increasing the hardness of the surface layer structure. The conditions for this nitriding heat treatment may be general conditions.

  Thereafter, the nitrogen compound layer 32 formed by cutting or grinding is processed and removed, and the nitrogen diffusion layer 33 is exposed on the sliding surface 3B of the valve plate 3 as shown in FIG.

  Next, as shown in FIG. 5, the nitrogen diffusion layer 33 is formed in the plating tank 51 in which the nonferrous soft metal that is the material of the nonferrous soft metal coating is in an electrolytic molten state with the valve plate 3 connected to the anode. The exposed sliding surface 3B is immersed. As a result, the non-ferrous soft metal coating 31 is formed on the sliding surface 3B where the nitrogen diffusion layer 33 of the valve plate 3 is exposed.

Further, the head casing 13 is produced in the order out of the production of the valve plate 3 as shown in FIGS.
First, the outer shape of the head casing 13 is produced from the FCD material 40.
Thereafter, nitriding heat treatment is performed on the outer shape of the manufactured head casing 13. By this nitriding heat treatment, as shown in FIG. 6A, a nitrogen diffusion layer 43 and a nitrogen compound layer 42 are formed on the surface layer of the sliding surface 13A of the head casing 13, thereby increasing the hardness of the surface layer structure. Here, as shown in FIG. 6B, the nitrogen compound layer 42 formed on the surface of the sliding surface 13A of the head casing 13 has a surface caused by the holes 45 from which the carbon derived from the FCD material has dropped. Defects 41a and 41b are present.

  The operation of one embodiment of the oblique axis hydraulic rotating machine of the present invention will be described.

  First, when the rotary shaft 4 is rotationally driven by a prime mover such as an engine (not shown), the cylinder block 5 rotates with the drive disk 8 around the center shaft 9, and each piston 6 reciprocates in each cylinder 15 of the cylinder block 5. Will be repeated. When the piston 6 retracts (extends) from within the cylinder 15, the intake stroke takes in the hydraulic oil from the tank 14, and when the piston 6 enters (shrinks) the cylinder 15, the hydraulic oil drawn into the cylinder 15 is removed. A discharge stroke is performed in which pressurized oil is discharged from the discharge passage 13B through the high-pressure side supply / discharge port.

  The pump discharge pressure at this time is supplied to the regulator 11 as a pilot pressure for capacity control. For example, when the pump discharge pressure rises, the pilot pressure rises and the regulator 11 operates to tilt from the pilot pump 22. A control pressure is supplied into the hydraulic chambers 17A and 17B. As a result, the servo piston 18 is driven in the direction indicated by the arrow A in FIG. 1, and the valve plate 3 connected to the servo piston 18 via the swing pin 16 is tilted at the tilt angle shown in FIG. It slides along the sliding contact surface 13A of the head casing 13 in the direction in which θ decreases, and the discharge amount of pressure oil decreases. At this time, the feedback link 21 is rotated following the tilting operation of the valve plate 3, and the regulator 19 is feedback-controlled by sliding the sleeve 19 in the same direction as the spool valve 20.

  In this way, the discharge amount of the pressure oil is variably controlled according to the pump discharge pressure, and the relationship between the discharge flow rate and the discharge pressure of the oblique axis hydraulic rotary machine is controlled along a desired characteristic line.

Here, the sliding surface 3B of the valve plate 3 and the sliding surface 13A of the head casing 13 each have a curved sliding contact surface, and slide at a high surface pressure during the tilting operation. In addition, since the posture is maintained by feedback control using the pump internal hydraulic pressure, reciprocal sliding with a very small stroke is always performed by the pulsation of the hydraulic pressure inside the oblique axis hydraulic press.
During this operation, a non-ferrous soft metal coating 31 formed on the sliding surface 3B of the valve plate 3 made of the steel base material 30 and a surface defect formed on the sliding surface 13A of the head casing 13 made of the FCD material 40. The nitrogen compound layer 42 having 41a and 41b slides, and a part of the non-ferrous soft metal coating 31 enters from the openings or crack gaps of the surface defects 41a and 41b, and exists immediately below the surface defects 41a and 41b. The carbon to be deposited adheres and fills into the holes 45 from which the carbon has dropped. As a result, the sliding surface 13A of the head casing 13 can be smoothed and the end of the nitrogen compound layer 42 in the surface defect 41a and the unstable nitrogen compound layer 44 that is the surface defect 41b can be supported. The plastic fluid structure 44 having the compound layer 42 and the nitrogen compound layer can be prevented from peeling off and the sliding state of both sliding surfaces 3B and 13A can be stabilized. Therefore, it is possible to obtain a hydraulic rotating machine including a sliding portion that prevents the occurrence of abnormal wear or seizure problems at the sliding portion and realizes a more stable sliding state.

  The nitriding surface treatment is not limited to nitriding heat treatment, and a known nitriding treatment such as salt bath nitriding or plasma nitriding can be used.

<Second Embodiment>
A second embodiment of the oblique axis type hydraulic rotating machine and the manufacturing method thereof according to the present invention will be described with reference to FIG. In FIG. 7 as well, a case where the present invention is applied to a variable displacement oblique axis type axial piston pump as an oblique axis type hydraulic rotating machine will be described as an example.

The configuration of the oblique-shaft hydraulic rotating machine in this embodiment is substantially the same as that of the first embodiment of the oblique-shaft hydraulic rotating machine, and the details of the structure are omitted. In addition, in the manufacturing method of the first embodiment of the manufacturing method of the slant axis type hydraulic rotating machine, the non-ferrous soft metal film forming means is configured to inject or project collision of fine particles of non-ferrous soft metal material at high speed. The method is substantially the same as that of the first embodiment except that a method for depositing and adhering is used, and details thereof are omitted.
FIG. 7 is a longitudinal sectional view showing a manufacturing process of the valve plate constituting the second embodiment of the oblique-axis hydraulic rotary machine of the present invention.

When the non-ferrous soft metal coating is formed on the sliding surface 3B where the nitrogen diffusion layer 33 of the valve plate 3 is exposed, as shown in FIG. 7, the sliding surface 3B of the valve plate 3 where the nitrogen diffusion layer 33 is exposed is formed. On the other hand, the fine particles 62 of the nonferrous soft metal material, which is the material of the nonferrous soft metal coating, are jetted and collided with the sliding surface 3B at high speed from the nozzle 61 by compressed air.
Thereby, the fine particles 62 colliding with the sliding surface 3B are adhered and deposited on the sliding surface 3B by plastic deformation, whereby the film 31a made of non-ferrous soft metal is formed on the sliding surface 3B surface of the valve plate 3. The non-ferrous soft metal coating 31 is formed.

The effects obtained in the oblique axis hydraulic rotating machine and the manufacturing method thereof according to the second embodiment are substantially the same as those of the oblique axis hydraulic rotating machine and the manufacturing method thereof according to the first embodiment.
Furthermore, in the manufacturing method of the slant axis type hydraulic rotating machine of the present embodiment, as a method for forming the non-ferrous soft metal coating 31, fine particles 62 of non-ferrous soft metal material are applied to the target portion where the non-ferrous soft metal coating 31 is formed. By using the method of spraying and adhering at a high speed, the coating 31 can be easily formed even in a deep hole shape or a part where the plating solution has poor throwing power. The soft metal coating 31 can be formed.
In addition, the non-ferrous soft metal coating 31 can be formed by selectively changing the film thickness with respect to a specific region in the sliding surface 3B, and the sliding surface pressure and sliding speed are increased in the sliding surface 3B. Even when they are different, it is possible to optimize the function by changing the film thickness according to each surface pressure and speed region, and it is possible to flexibly cope with the usage.

  The material of the fine particles 62 may be at least one of lead, tin, and copper, for example.

  Further, when the fine particles 62 are jetted and collided, by selectively increasing or decreasing the collision time of the fine particles 62 with respect to a specific region of the sliding surface, the sliding surface pressure and sliding in the sliding surface can be reduced. It is possible to optimize the thickness of the non-ferrous soft metal coating 31 in accordance with the speed.

<Third Embodiment>
A third embodiment of the oblique axis type hydraulic rotating machine and the manufacturing method thereof according to the present invention will be described with reference to FIGS. In FIGS. 8 and 9, a case where the present invention is applied to a variable displacement oblique axis type axial piston pump as an oblique axis type hydraulic rotating machine will be described as an example.

The configuration of the oblique-shaft hydraulic rotating machine in this embodiment is substantially the same as that of the first embodiment of the oblique-shaft hydraulic rotating machine, and the details of the structure are omitted. In addition, in the manufacturing method of the first embodiment of the manufacturing method of the oblique-axis hydraulic rotating machine, the non-ferrous soft metal coating forming means is provided with a phosphate coating on the formation target portion of the non-ferrous soft metal coating. After the formation, it is substantially the same as the first embodiment except that a method of forming the outermost surface of the coating and the non-ferrous soft metal component by chemical substitution is used, and details are omitted. Here, a specific example in which the phosphate component is manganese phosphate and the non-ferrous soft metal component is tin will be described.
FIG. 8 is a cross-sectional view showing the manufacturing process of the valve plate constituting the third embodiment of the oblique-axis hydraulic rotating machine of the present invention, and FIG. FIG. 8B is an enlarged cross-sectional view showing a portion A of FIG. 8A, and FIG. 9 shows a third embodiment of the oblique-axis hydraulic rotating machine of the present invention. FIG. 9A is a longitudinal sectional view showing a part of the valve plate in cross section, and FIG. 9B is an enlarged view of part A of FIG. 9A. It is sectional drawing shown.

In forming the non-ferrous soft metal coating 31 on the sliding surface 3B where the nitrogen diffusion layer 33 of the valve plate 3 is exposed, first, as shown in FIG. 8A, the valve plate 3 with the nitrogen diffusion layer 33 exposed is exposed. The sliding surface 3B is immersed in a chemical bath 71 of a reaction solution of manganese phosphate, and a manganese phosphate film 34 as shown in FIG. 8B is formed on the sliding surface 3B by a chemical reaction.
Furthermore, as shown to Fig.9 (a), the valve plate 3 in which the manganese phosphate membrane | film | coat 34 was formed is immersed in the chemical | medical solution layer 72 of the reaction solution which has a 1st tin chloride as a main component. As a result, the outermost surface layer of the manganese phosphate coating 34 and the stannous chloride are chemically substituted to form a tin phosphate coating 35 as shown in FIG. A coating 31 is formed.

The effects obtained in the oblique-shaft hydraulic rotating machine and the manufacturing method thereof according to the third embodiment are substantially the same as those of the oblique-shaft hydraulic rotating machine and the manufacturing method thereof according to the first embodiment.
Furthermore, in the manufacturing method of the slant axis type hydraulic rotating machine of this embodiment, after forming the phosphate film 34 with respect to the formation object site | part of the nonferrous soft metal coating 31, as a formation method of the nonferrous soft metal coating 31, By using a method of chemically replacing the outermost surface of the phosphate film 34 and the non-ferrous soft metal component, the adhesion of the non-ferrous soft metal film 31 to the sliding surface 3B of the valve plate 3 is improved. As a result, the non-ferrous soft metal coating 31 has a very small peeling loss due to abnormal film formation, and the effect of filling surface defects can be stably exhibited.

<Others>
In each of the embodiments, the variable displacement oblique shaft hydraulic pump has been described as an example of the oblique shaft hydraulic rotating machine. However, the present invention is not limited to this, and for example, the variable displacement oblique shaft hydraulic The present invention can be applied to a motor, and can also be applied to a fixed displacement type oblique axis hydraulic pump, a hydraulic motor, and the like.

  In each embodiment, the member made of steel is the valve plate 3, the member made of spheroidal graphite cast iron is the head casing 13, and the sliding portion between the valve plate 3 and the head casing 13 is described as an example. However, the present invention is not limited to this, and the present invention can be applied to all sliding portions formed of a member made of steel and a member made of spheroidal graphite cast iron.

1 ... Variable displacement oblique axis type axial piston pump,
2 ... casing,
3 ... valve plate,
3A ... sliding surface (with the cylinder block 5 in the valve plate 3),
3B ... Sliding surface (with the head casing 13 in the valve plate 3),
3C ... through hole,
4 ... Rotating shaft,
5 ... Cylinder block,
5A ... sliding surface (with the valve plate 3 in the cylinder block 5),
6 ... Piston,
7 ... Connecting rod,
8 ... Drive disk,
9 ... Center shaft,
10 ... Tilt mechanism,
11 ... Regulator,
12 ... the casing body,
12A ... upper opening,
13 ... head casing,
13A ... sliding surface (with the valve plate 3 in the head casing 13),
13B ... discharge passage,
14 ... Tank,
15 ... cylinder,
16: Swing pin,
17 ... Piston sliding hole,
17A, 17B ... hydraulic chamber,
18 ... Servo piston,
19 ... Sleeve,
20 ... Spool valve,
21 ... Feedback link,
22 ... Pilot pump,
30 ... steel,
31 ... non-ferrous soft metal coating,
31a: film made of non-ferrous soft metal,
32, 42 ... nitrogen compound layer,
33, 43 ... Nitrogen diffusion layer,
34 ... Manganese phosphate coating,
35 ... tin phosphate coating,
40 ... FCD material,
41a, 41b ... surface defects,
44. Plastic flow structure,
45: holes (holes from which carbon has dropped),
51 ... Plating tank,
61 ... Nozzle,
62 ... non-ferrous soft metal fine particles,
71, 72 ... Chemical tank.

Claims (5)

A slant shaft type hydraulic rotating machine having a sliding portion that slidably contacts one sliding surface of one member that is a steel material and the other sliding surface of another member that is a spheroidal graphite cast iron material,
The one sliding surface on which a non-ferrous soft metal film made of at least one metal of lead, tin, and copper is formed after processing and removing the nitrogen compound layer formed by nitriding surface treatment on the sliding surface When,
And the other sliding surface in which the non-ferrous soft metal coating is intruded and filled into the hole from which carbon, which is a surface defect present in the nitrogen compound layer formed by nitriding surface treatment on the sliding surface, is dropped. Oblique shaft type hydraulic rotating machine. A manufacturing method of a slant shaft type hydraulic rotating machine provided with a sliding portion that slidably contacts one sliding surface of one member made of steel and the other sliding surface of another member made of spheroidal graphite cast iron. There,
Nitride-based surface treatment is performed on the one member, and then nitrogen compound removal formed on the surface of one sliding surface of the one member is removed to expose the nitrogen diffusion layer, and the exposed nitrogen Forming the one sliding surface by forming a non-ferrous soft metal film made of at least one metal of lead, tin, and copper on the surface of the diffusion layer,
A manufacturing method of a slant axis type hydraulic rotating machine characterized in that a nitrogen compound layer is formed on the other member to form a nitrogen compound layer to form the other sliding surface of the other member. In the manufacturing method of the slant axis type hydraulic rotating machine according to claim 2,
The manufacturing method of the slant axis | shaft type hydraulic rotating machine characterized by forming the said nonferrous soft metal film by plating. In the manufacturing method of the slant axis type hydraulic rotating machine according to claim 2,
The oblique axis characterized in that the non-ferrous soft metal coating is formed by depositing and adhering fine particles made of non-ferrous soft metal material at a high speed by jetting or projecting on the target site of the non-ferrous soft metal coating. Manufacturing method of a hydraulic press. In the manufacturing method of the slant axis type hydraulic rotating machine according to claim 2,
Forming a phosphate film on the nonferrous soft metal film formation target portion of the nonferrous soft metal film, and then chemically replacing the outermost surface of the phosphate film and the nonferrous soft metal component The manufacturing method of the slant axis | shaft type hydraulic rotating machine characterized by the above-mentioned.

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