Manufacturing method of hydraulic motor / pump and rear cover

Abstract

The invention provides a hydraulic motor / pump and a manufacturing method of a rear cover, the hydraulic motor / pump comprises a cylinder body and the rear cover which rotate relatively, the rear cover forms a part of a shell of the motor / pump, and a first area of the rear cover is in contact with a second area of the cylinder body to form a friction pair; the first area is provided with an oil inlet for guiding hydraulic oil into the cylinder body, an oil outlet for guiding the hydraulic oil out of the cylinder body and a plurality of flow distribution grooves, and the flow distribution grooves communicate with the oil inlet and the oil outlet correspondingly. One of the first region and the second region forms a hardened layer by surface hardening. By means of the arrangement, a gap between the valve plate and the rear cover is avoided, hydraulic oil can be prevented from leaking between the valve plate and the rear cover when the motor or the pump works, leakage of the hydraulic oil is reduced, and pressure loss of the hydraulic oil is reduced. The hardness of one of the first area and the second area is increased, the requirements for abrasion resistance and high hardness are met under the conditions of low cost and small deformation, and therefore the service life of the rear cover and the service life of the cylinder body are prolonged.

Description

Technical Field

[0001] This application relates to the technical field of hydraulic equipment, and particularly relates to a manufacturing method of a hydraulic motor / pump and a rear cover. Background Art

[0002] In the structure of a hydraulic motor or pump, a flow distribution plate is provided between the relatively rotating rear cover and the cylinder block. When the hydraulic motor or pump is working, there will be a certain amount of leakage of hydraulic oil in the gaps between the flow distribution plate and the cylinder block and between the flow distribution plate and the rear cover, which will also cause pressure loss of the hydraulic oil. Moreover, the relatively rotating cylinder block and the flow distribution plate will generate relative friction, reducing the service life of the flow distribution plate and the cylinder block. Summary of the Invention

[0003] In view of this, this application provides a hydraulic motor / pump, which solves the problems of hydraulic oil leakage between the flow distribution plate and the cylinder block and between the flow distribution plate and the rear cover, resulting in pressure loss of the hydraulic oil, and reducing the service life of the flow distribution plate and the cylinder block. This application also provides a manufacturing method of a rear cover.

[0004] In order to achieve the above object, this application provides the following technical solutions:

[0005] A hydraulic motor / pump includes a relatively rotating cylinder block and a rear cover. The rear cover forms a part of the outer shell of the motor / pump. A first region of the rear cover contacts a second region of the cylinder block to form a friction pair, and:

[0006] The first region is provided with an oil inlet for introducing hydraulic oil into the cylinder block, an oil outlet for discharging the hydraulic oil in the cylinder block, and a plurality of flow distribution grooves. The plurality of flow distribution grooves are respectively communicated with the oil inlet and the oil outlet;

[0007] One of the first region and the second region forms a hardened layer by surface hardening.

[0008] Optionally, a wear-resistant layer is provided on the other one of the first region and the second region where the hardened layer is not formed, and the hardness of the wear-resistant layer is less than the hardness of the hardened layer.

[0009] Optionally, the first region forms a hardened layer, and the wear-resistant layer is provided on the surface of the second region.

[0010] Optionally, the material of the cylinder block is set as nodular iron or high alloy steel, and the second region forms the hardened layer; the wear-resistant layer is provided on the first region.

[0011] Optionally, the material of the cylinder block is set as nodular iron or high alloy steel, and the second region forms the hardened layer; the material of the rear cover is set as nodular iron, and the wear-resistant layer is not provided on the first region.

[0012] Optionally, the thickness of the hardened layer is 0.1 mm - 0.5 mm.

[0013] Optionally, the surface hardening includes laser hardening or high-frequency hardening.

[0014] Optionally, the wear-resistant layer is an additional layer formed by sintering or cladding copper or a copper alloy on the surface of the first region or the second region.

[0015] A manufacturing method of a rear cover includes the following steps:

[0016] Machine a flow distribution groove in the first region of the rear cover;

[0017] Perform surface hardening on the first region to form a hardened layer.

[0018] Optionally, the surface hardening is laser hardening, wherein:

[0019] The wavelength of the laser is 500 nm - 2000 nm;

[0020] The power of the laser is greater than 3 KW;

[0021] The spot width of the laser is 10 mm - 50 mm;

[0022] The scanning speed of the laser is 2 mm / s - 20 mm / s.

[0023] The hydraulic motor / pump provided by the present application opens an oil inlet for introducing hydraulic oil into the cylinder block, an oil outlet for discharging the hydraulic oil in the cylinder block, and a plurality of flow distribution grooves in the first region of the rear cover, and arranges the flow distribution disk on the rear cover, that is, the flow distribution disk and the rear cover are set as an integral structure. In this way, the gap between the flow distribution disk and the rear cover is avoided. When the hydraulic motor or the hydraulic pump is working, the leakage of hydraulic oil from between the flow distribution disk and the rear cover can be avoided, thereby reducing the leakage of hydraulic oil and reducing the pressure loss of the hydraulic oil. By forming a hardened layer on one of the first region and the second region through surface hardening, the hardness of one of the first region and the second region is increased, and the requirements of wear resistance and high hardness are achieved under the conditions of low cost and small deformation, thereby extending the service life of the rear cover and the cylinder block. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0025] Figure 1It is a three-dimensional view of the cylinder block, valve plate and rear cover of a hydraulic motor / pump in the background art;

[0026] Figure 2 It is a three-dimensional view of the cylinder block and rear cover of the hydraulic motor / pump provided in this embodiment;

[0027] In Figure 1 - Figure 2 :

[0028] 1 - Cylinder block, 2 - Rear cover, 3 - Valve plate;

[0029] 21 - First region, 22 - Second region;

[0030] 211 - Oil inlet, 212 - Oil outlet, 213 - Flow distribution groove. Detailed implementation mode

[0031] This application provides a hydraulic motor / pump. This application also provides a manufacturing method for the rear cover.

[0032] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0033] In the prior art, a valve plate is provided between the cylinder block and the rear cover of the hydraulic motor / pump. In this way, there are inevitable gaps between the cylinder block and the valve plate and between the rear cover and the valve plate. In this way, during the process of hydraulic oil flowing from the rear cover to the cylinder block or from the cylinder block to the rear cover, the hydraulic oil may flow out between the cylinder block and the valve plate and between the rear cover and the valve plate, resulting in the loss of hydraulic oil and the pressure loss of the hydraulic oil.

[0034] Such as Figure 1 - Figure 2As shown, an embodiment of the present application provides a hydraulic motor / pump, which can be installed in a mechanical structure such as a hydraulic device to provide power and motion control capabilities for various devices and systems, or to provide fluid power support for various devices. The hydraulic motor / pump mainly includes a relatively rotating cylinder block 1 and a rear cover 2. The rear cover 2 forms a part of the outer shell of the hydraulic motor / pump. The first region 21 of the rear cover 2 contacts the second region 22 of the cylinder block 1 to form a friction pair. When the cylinder block 1 and the rear cover 2 are the cylinder block 1 and the rear cover 2 of the motor, high-pressure hydraulic oil is introduced into the cylinder block 1 of the motor through the rear cover 2 to provide power for the rotation of the motor, and then the low-pressure hydraulic oil is exported from the cylinder block 1 through the rear cover 2, thereby converting hydraulic energy into the rotational mechanical energy of the cylinder block 1; when the cylinder block 1 and the rear cover 2 are the cylinder block 1 and the rear cover 2 of the pump, through the rotation of the cylinder block 1 relative to the rear cover 2, the low-pressure hydraulic oil is introduced into the cylinder block 1 of the pump through the rear cover 2, and the hydraulic oil is compressed by the rotation of the cylinder block 1 of the pump, and the high-pressure hydraulic oil is introduced from the cylinder block 1 into the rear cover 2, thereby converting the rotational mechanical energy of the cylinder block 1 into the hydraulic energy of the high-pressure hydraulic oil.

[0035] In this embodiment, an oil inlet 211 for introducing hydraulic oil into the cylinder block 1, an oil outlet 212 for exporting the hydraulic oil in the cylinder block 1, and a plurality of distribution grooves 213 are provided in the first region 21. The plurality of distribution grooves 213 are respectively communicated with the oil inlet 211 and the oil outlet 212. Specifically, the oil inlet 211, the oil outlet 212, and the distribution grooves 213 are provided in the first region 21, and the functions of the oil inlet 211, the oil outlet 212, and the distribution grooves 213 are the same as those of the oil inlet 211, the oil outlet 212, and the distribution grooves 213 in the distribution disk 3, which is equivalent to setting the rear cover 2 and the distribution disk 3 as an integral structure. In the prior art, a distribution disk 3 is provided between the rear cover 2 and the cylinder block 1. When the hydraulic oil is introduced into the cylinder block 1 or exported from the cylinder block 1 through the oil inlet 211 or the oil outlet 212 of the distribution disk 3, the hydraulic oil may flow out from the gap between the distribution disk 3 and the cylinder block 1, or may flow out from the gap between the distribution disk 3 and the rear cover 2. And when the high-pressure hydraulic oil is lost, it will cause the pressure of the high-pressure hydraulic oil to decrease, resulting in the loss of the hydraulic oil pressure, and the loss of the hydraulic oil will also reduce the hydraulic volume efficiency. Here, by setting the rear cover 2 and the distribution disk 3 as an integral structure, it is possible to avoid the loss of the hydraulic oil from the gap between the distribution disk 3 and the rear cover 2, reduce the loss of the hydraulic oil, and at the same time reduce the loss of the hydraulic oil pressure.

[0036] Further, a hardened layer is formed by surface hardening in one of the first region 21 and the second region 22. Here, by forming a hardened layer in one of the first region 21 and the second region 22 through surface hardening, the hardness of one side of the first region 21 close to the second region 22 or one side of the second region 22 close to the first region 21 is increased, so that the requirements of wear resistance and high hardness are met for this region at low cost and with small deformation. In this way, when the second region 22 of the cylinder block 1 rubs against the first region 21 of the rear cover 2, the wear degree of the region without the hardened area and the region with the hardened area can be reduced, thereby extending the service life of the cylinder block 1 and the rear cover 2.

[0037] It should be noted that the structures and functions of the oil inlet 211, the oil outlet 212 and the flow distribution groove 213 provided in the first region 21 are the same as those of the oil inlet 211, the oil outlet 212 and the flow distribution groove 213 provided on the flow distribution disk 3 in the prior art, and will not be elaborated here.

[0038] It should also be noted that when used as a motor, the oil inlet 211 and the oil outlet 212 are symmetrically arranged along the center of the first region 21, and a plurality of flow distribution grooves 213 are provided, and each flow distribution groove communicates with an oil inlet 211 or an oil outlet 212; when used as a pump, the flow distribution grooves 213, the oil inlet 211 and the oil outlet 212 can be designed in different shapes.

[0039] It should be noted again that quenching is a metal heat treatment process in which a metal material is rapidly cooled to obtain specific physical and mechanical properties. The purpose of quenching is to improve the hardness, strength and wear resistance of the metal, and to adjust its organizational structure.

[0040] It should be noted again that the second region 22 refers to Figure 2 the region corresponding to the lower end surface of the middle cylinder block 1 and the first region 21 of the rear cover 2, that is, the region where the first region 21 of the cylinder block 1 and the rear cover 2 rotate and contact relatively.

[0041] For the hydraulic motor / pump with the above structure, by providing an oil inlet 211 for introducing hydraulic oil into the cylinder block 1, an oil outlet 212 for discharging the hydraulic oil in the cylinder block 1 and a plurality of flow distribution grooves 213 in the first region 21 of the rear cover 2, the flow distribution disk 3 is provided on the rear cover 2, that is, the flow distribution disk 3 and the rear cover 2 are set as an integral structure. In this way, the gap between the flow distribution disk 3 and the rear cover 2 is avoided. In this way, when the motor or the pump is working, the leakage of hydraulic oil from between the flow distribution disk 3 and the rear cover 2 can be avoided, thereby reducing the leakage of hydraulic oil and reducing the pressure loss of the hydraulic oil. By forming a hardened layer in one of the first region 21 and the second region 22 through surface hardening, the hardness of one of the first region 21 and the second region 22 is increased, so that the requirements of wear resistance and high hardness are met at low cost and with small deformation, thereby extending the service life of the rear cover 2 and the cylinder block 1.

[0042] In some embodiments, a wear-resistant layer is provided on the other one of the first region 21 and the second region 22 where no hardened layer is formed, and the hardness of the wear-resistant layer is less than that of the hardened layer. Specifically, a hardened layer is provided on one of the first region 21 and the second region 22. On this basis, a wear-resistant layer is provided on the other one of the first region 21 and the second region 22 where no hardened layer is formed. Setting the wear-resistant layer can improve the wear resistance of the second region 22 of the cylinder block 1 or the first region 21 of the rear cover 2 when they rub against each other, reduce the wear of the second region 22 of the cylinder block 1 and the first region 21 of the rear cover 2 during the friction process, and extend the service life of the cylinder block 1 and the rear cover 2. Further, ensuring that the hardness of the wear-resistant layer is less than that of the hardened layer can ensure a hardness difference between the second region 22 of the cylinder block 1 and the first region 21 of the rear cover 2. In this way, during the relative rotation of the cylinder block 1 and the rear cover 2, the wear of the second region 22 of the cylinder block 1 and the first region 21 of the rear cover 2 during the friction process can be further reduced, and the friction damage caused by the excessive strength of the second region 22 of the cylinder block 1 and the first region 21 of the rear cover 2 can be avoided, thus extending the service life of the cylinder block 1 and the rear cover 2.

[0043] It should be noted that regarding the setting positions of the hardened layer and the wear-resistant layer in the first region 21 and the second region 22, by way of example, a hardened layer can be formed in the first region 21 by surface quenching, and a wear-resistant layer can be provided in the second region 22; or a hardened layer can be formed in the second region 22 by surface quenching, and a wear-resistant layer can be provided in the first region 21.

[0044] In some embodiments, a hardened layer is formed in the first region 21, and a wear-resistant layer is provided on the surface of the second region 22. Specifically, the first region 21 of the rear cover 2 is generally a planar structure, and the plane is conducive to processing. Quenching in the first region 21 to form a hardened layer can improve the working efficiency and the processing forming effect is good; setting a wear-resistant layer in the second region 22 by sintering / cladding with metal powder or metal alloy powder has simple processing operations and high processing efficiency. And when a hardened layer is formed in the first region 21 and a wear-resistant layer is provided on the surface of the second region 22, when the first region 21 and the second region 22 rotate relative to each other, the working effect is good, the friction loss can be reduced, and thus the service life of the cylinder block 1 and the rear cover 2 can be extended.

[0045] In some embodiments, the material of the cylinder block 1 is set as nodular cast iron or high alloy steel, and a hardened layer is formed in the second region 22; a wear-resistant layer is provided on the first region 21. Specifically, when the material of the cylinder block 1 is nodular cast iron, a hardened layer is formed in the second region 22 to increase the hardness of the second region 22, and a wear-resistant layer is provided in the first region 21. With such a setting, there is a hardness difference between the first region 21 and the second region 22, so that when the cylinder block 1 and the rear cover 2 rotate relative to each other, the frictional loss of the first region 21 and the second region 22 is reduced; when the material of the cylinder block 1 is high alloy steel, the hardness of the material of the cylinder block 1 itself is already very high, and then a hardened layer is formed in the second region 22 of the cylinder block 1 to further increase the hardness of the second region 22 and further increase the hardness difference between the first region 21 and the second region 22, so that when the cylinder block 1 and the rear cover 2 rotate relative to each other, the frictional loss of the first region 21 and the second region 22 is further reduced.

[0046] In some embodiments, the material of the cylinder block 1 is set as nodular cast iron or high alloy steel, and a hardened layer is formed in the second region 22; the material of the rear cover 2 is set as nodular cast iron, and no wear-resistant layer is provided on the first region 21. Specifically, whether the material of the cylinder block 1 is nodular cast iron or high alloy steel, a hardened layer is formed in the second region 22 to increase the hardness of the second region 22; on this basis, the material of the first region 21 is set as nodular cast iron. Since the hardness of nodular cast iron is small, even if the setting of the wear-resistant layer is omitted in the first region 21, a large hardness difference can still be formed between the hardened layer in the second region 22 and the nodular cast iron in the first region 21, so that when the cylinder block 1 and the rear cover 2 rotate relative to each other, the frictional loss is reduced and the service life of the cylinder block 1 and the rear cover 2 is extended.

[0047] In some embodiments, the thickness of the hardened layer is 0.1 mm - 0.5 mm. Specifically, the thickness of the hardened layer refers to the dimension in the direction perpendicular to the surface of the first region 21 or the surface of the second region 22. The direction perpendicular to the surface of the first region 21 or the surface of the second region 22 refers to Figure 2 the direction indicated by the double-headed arrow A in. Here, controlling the thickness of the hardened layer within the above range can greatly improve the hardness and wear resistance of the surface of the region where the hardened layer is provided, and avoid excessive increase in the thickness of the region where the hardened layer is provided, ensuring the overall tightness of the structure.

[0048] It should be noted that the hardened layer is a layered structure provided on the surface of one of the first region 21 and the second region 22 and is not shown in the figure.

[0049] Exemplarily, the thickness of the hardened layer can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc.

[0050] In addition, the thickness of the hardened layer can also be greater than 0.5 mm. Exemplarily, the thickness of the hardened layer can also be 0.6 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, and so on.

[0051] In some embodiments, the hardness of the hardened layer is 400 HV to 700 HV. The hardness of this area before the hardened layer is set is 200 HV. The hardened layer can greatly increase the hardness of this area, and its hardness and wear resistance far exceed the surface of the currently commonly used valve plates.

[0052] Exemplarily, the hardness of the hardened layer is 400 HV, 500 HV, 550 HV, 600 HV, 650 HV, 700 HV, and so on.

[0053] In some embodiments, surface hardening includes laser hardening or high-frequency hardening.

[0054] It should be noted that laser hardening is a method of quenching treatment using laser technology. Compared with traditional quenching methods, laser hardening has unique advantages and characteristics. Laser hardening is achieved by focusing a high-energy laser beam on the surface of a metal material, rapidly heating and cooling the metal to achieve the quenching effect. During the laser hardening process, the high energy density of the laser beam can quickly heat the metal surface to a high temperature, and then through rapid cooling, the metal material undergoes a phase transformation to form a high-hardness martensite structure.

[0055] Among them, laser hardening has the following advantages compared with traditional quenching methods: rapid heating and cooling. The high energy density of the laser beam can quickly heat and cool the metal surface, achieving a very rapid quenching process. This helps to reduce deformation and residual stress during the quenching process; local heating control. Laser hardening can achieve local heating of the metal material, only applying high temperature to the area that needs to be quenched, avoiding the need for overall heating; high hardness and surface quality. Laser hardening can produce a high-hardness martensite structure, providing excellent surface hardness and wear resistance; at the same time, the rapid cooling during the laser hardening process can reduce the time of tissue transformation, thereby reducing the tempering effect during the quenching process and improving the hardness and performance of the workpiece; flexibility and automation. Laser hardening can be adjusted and optimized according to specific requirements, and is suitable for different types of metal materials and workpieces.

[0056] In addition, laser hardening can be integrated with an automated system to achieve efficient and precise quenching treatment. Laser hardening can provide a more precise, efficient, and controllable quenching treatment, significantly improving the performance and lifespan of the workpiece.

[0057] It should also be noted that high-frequency quenching is a method of quenching treatment using high-frequency induction heating technology. It achieves the quenching effect by introducing high-frequency current into the workpiece and utilizing the resistance heating effect of the workpiece. During high-frequency quenching, the workpiece is placed in an induction coil, which is powered by a high-frequency power supply. When the high-frequency current passes through the induction coil, an alternating magnetic field is generated on the surface of the workpiece. Due to the resistance of the workpiece, the alternating magnetic field generates eddy currents on the surface of the workpiece, thereby rapidly heating the surface of the workpiece. During the heating process, the surface temperature of the workpiece rises, and then the quenching effect is achieved through rapid cooling. Usually, water spraying or spray coolant is used to rapidly cool the workpiece, so that a high-hardness martensite structure is formed on the surface of the workpiece.

[0058] Among them, high-frequency quenching has the following advantages compared with traditional quenching methods: rapid heating and cooling, high-frequency induction heating can heat the surface of the workpiece to the required temperature in a very short time, and then achieve quenching through rapid cooling, which helps to reduce deformation and residual stress during the quenching process; high hardness and surface quality, high-frequency quenching can produce a high-hardness martensite structure, providing excellent surface hardness and wear resistance. At the same time, due to the very rapid heating and cooling process, the time of tissue transformation can be reduced, thereby reducing the tempering effect during the quenching process and improving the hardness and performance of the workpiece; flexibility and automation, high-frequency quenching can be adjusted and optimized according to specific requirements and is suitable for different types of metal materials and workpieces.

[0059] In addition, high-frequency quenching can be integrated with an automated system to achieve efficient and precise quenching treatment. High-frequency quenching can provide more precise, efficient and controllable quenching treatment, significantly improving the performance and service life of the workpiece.

[0060] In some embodiments, the wear-resistant layer is provided as an additional layer formed by sintering or cladding the surface of copper or copper alloy in the first region 21 or the second region 22. Specifically, the wear-resistant layer is formed by laying metal powder or metal alloy powder in the first region 21 and the second region 22, and then forming an additional layer through surface sintering or cladding. Here, copper powder or copper alloy powder is preferably used, which can reduce the hardness of the wear-resistant layer, thereby increasing the hardness difference between the hardened layer and the wear-resistant layer provided in the first region 21 and the second region 22, thereby reducing the frictional loss between the cylinder block 1 and the rear cover 2 and increasing the wear resistance of the first region 21 or the second region 22.

[0061] It should be noted that sintering is a process of heating powdered substances at high temperature to make the particles bond with each other. During the sintering process, the powdered substances undergo thermoplastic deformation at high temperature, the contact area between particles increases, and through diffusion and reduction of surface energy, the bonding force between particles is formed. Cladding is a surface coating technology that melts or semi-melts materials through a heat source and then sprays them onto the surface of a substrate to form a coating. The cladding technology can form a coating with specific properties and functions on the surface of the substrate to improve the performance of the substrate, protect the substrate, or repair damaged parts.

[0062] In addition, the powder used for sintering or cladding can also be other metal powders, such as iron powder, aluminum powder, nickel powder, etc.

[0063] A manufacturing method for a rear cover 2, which is usually the rear cover 2 of a motor / pump. After the rear cover 2 is manufactured, it is assembled with the cylinder block 1 of the motor / pump, and the rear cover 2 forms a part of the motor / pump. The manufacturing method of the rear cover 2 includes the following steps: machining a flow distribution groove 213 in the first region 21 of the rear cover 2; performing surface hardening on the first region 21 to form a hardened layer. Specifically, in the prior art, an oil inlet 211 and an oil outlet 212 adapted to the cylinder block are provided on the rear cover 2. In this embodiment, when machining the flow distribution groove 213 in the first region 21, it is preferred to open multiple flow distribution grooves 213 and ensure that the multiple flow distribution grooves 213 are respectively communicated with the oil inlet 211 and the oil outlet 212. In this way, the first region 21 of the rear cover 2 functions as a flow distribution plate 3, which is equivalent to integrally setting the flow distribution plate 3 and the rear cover 2. With this setting, during the operation of the motor / pump, it can effectively prevent hydraulic oil from flowing out between the flow distribution plate 3 and the rear cover 2, avoiding the loss and waste of hydraulic oil at this position, and avoiding the pressure loss caused by the loss of hydraulic oil at this position. Then, surface hardening is performed on the first region 21 to form a hardened layer. By performing surface hardening on the surface of the first region 21 to form a hardened layer, the hardness of the first region 21 near the second region 22 is increased, so as to meet the requirements of wear resistance and high hardness in the case of low cost and small deformation. With this setting, when the second region 22 of the cylinder block 1 rubs against the first region 21 of the rear cover 2, the wear degree of the second region 22 without the hardened layer and the first region 21 with the hardened layer can be reduced, thereby extending the service life of the cylinder block 1 and the rear cover 2.

[0064] It should be noted that the quenching method for the first region 21 can be laser quenching or high-frequency quenching.

[0065] It should also be noted that the method for opening the flow distribution groove 213 on the rear cover 2 can be: cutting and grooving, such as using a saw blade milling cutter, ball nose milling cutter, etc. to groove the rear cover 2; drilling, using a drill bit to groove the rear cover 2; laser grooving, using a laser to groove the rear cover 2; water jet grooving, using high-pressure water flow and abrasive to groove the rear cover 2.

[0066] Furthermore, after quenching, the hardened layer is further ground and polished to make the roughness of the hardened layer Ra0.1. In this way, during the relative rotation of the rear cover and the cylinder block, the ground and polished hardened layer can reduce the friction between the hardened layer and the other, and improve the service life of the rear cover and the cylinder block.

[0067] In some embodiments, the surface quenching is laser quenching. The surface quenching is laser quenching, where: the wavelength of the laser is 500nm - 2000nm; the power of the laser is greater than 3KW; the spot width of the laser is 10mm - 50mm; the scanning speed of the laser is 2mm / s - 20mm / s. Here, ensuring that the parameters of the laser are within the above ranges can quickly achieve the surface quenching and improve the surface hardness, so as to meet the requirements of wear resistance and high hardness at low cost and with small deformation, thereby extending the service life of the rear cover and the cylinder block. Laser quenching has the advantages of high precision and locality, rapid heating and cooling, low deformation and residual stress, flexibility and automation, and no need for a cooling medium.

[0068] In addition, the surface can also be quenched by existing high-frequency quenching. High-frequency quenching utilizes the principle of high-frequency electromagnetic induction heating and can quickly heat metal parts to the required temperature; compared with traditional heating methods, high-frequency quenching has a faster heating speed and can achieve uniform heating in a short time; at the same time, during the quenching process, the parts can also be quickly cooled to reach the required hardness; high-frequency quenching can control the required hardness and microstructure by adjusting the heating and cooling parameters; since the surface hardening only affects the surface layer of the parts and the interior maintains a certain toughness, a balance can be achieved between the strength and wear resistance of the parts; the heating process of high-frequency quenching is very efficient and can quickly transfer energy to metal parts, reducing the heating time and energy consumption. In addition, due to the rapid cooling process of high-frequency quenching, the usage amount and cooling time of the cooling medium are also reduced, further improving the energy utilization efficiency.

[0069] The basic principles of the present application have been described above in combination with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are only examples and not limitations. It cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present application. In addition, the above-disclosed specific details are only for illustrative and easy-to-understand purposes, rather than limitations. The above details do not limit the present application to necessarily adopt the above specific details to be implemented.

[0070] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any way. Words such as "including", "comprising", "having", etc. are open-ended terms, meaning "including but not limited to", and can be used interchangeably with each other. The words "or" and "and" used herein refer to the phrase "and / or" and can be used interchangeably with it, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to" and can be used interchangeably with it.

[0071] It should also be noted that in the devices, equipment, and methods of this application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of this application.

[0072] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

[0073] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth", and "sixth" used in the description of the embodiments of this application are only for more clearly elaborating the technical solutions and cannot be used to limit the protection scope of this application.

[0074] The above description has been given for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions, and sub-combinations thereof.

Claims

1. A hydraulic motor / pump, characterized in that, Comprising a relatively rotatable cylinder block and a rear cover, the rear cover forming part of the housing of the hydraulic motor / pump, a first region of the rear cover being in contact with a second region of the cylinder block to form a friction pair, and: The first region is provided with an oil inlet for introducing hydraulic oil into the cylinder block, an oil outlet for discharging the hydraulic oil in the cylinder block, and a plurality of flow distribution grooves, the plurality of flow distribution grooves being respectively communicated with the oil inlet and the oil outlet; One of the first region and the second region is formed with a hardened layer by surface hardening.

2. The hydraulic motor / pump according to claim 1, characterized in that, A wear-resistant layer is provided on the other of the first region and the second region where the hardened layer is not formed, and the hardness of the wear-resistant layer is less than the hardness of the hardened layer.

3. The hydraulic motor / pump according to claim 2, characterized in that, The first region is formed with a hardened layer, and the wear-resistant layer is provided on the surface of the second region.

4. The hydraulic motor / pump according to claim 2, characterized in that, The material of the cylinder block is set as nodular iron or high alloy steel, and the second region is formed with the hardened layer; the wear-resistant layer is provided on the first region.

5. The motor / pump according to claim 1, characterized in that, The material of the cylinder block is set as nodular iron or high alloy steel, and the second region is formed with the hardened layer; the material of the rear cover is set as nodular iron, and the wear-resistant layer is not provided on the first region.

6. The hydraulic motor / pump according to any one of claims 1-5, characterized in that, The thickness of the hardened layer is 0.1mm - 0.5mm.

7. The hydraulic motor / pump according to claim 6, characterized in that, The surface hardening includes laser hardening or high-frequency hardening.

8. The hydraulic motor / pump according to claim 2, characterized in that, The wear-resistant layer is set as an additional layer formed by sintering or cladding copper or copper alloy on the surface of the first region or the second region.

9. A manufacturing method of a rear cover, characterized in that, Including the following steps: Machining flow distribution grooves in the first region of the rear cover; Performing surface hardening on the first region to form a hardened layer.

10. The manufacturing method of the rear cover according to claim 9, characterized in that, The surface hardening is laser hardening, wherein: The wavelength of the laser is 500nm - 2000nm; The power of the laser is greater than 3KW; The spot width of the laser is 10mm - 50mm; The scanning speed of the laser is 2mm / s - 20mm / s.

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