A method for making a combined hydraulic amplifier

Abstract

The present application belongs to the field of hydraulic control, and relates to a combined hydraulic amplifier manufacturing method, which comprises the following steps: (1) preparing materials; (2) processing upper and lower blocks; (3) heat treatment; (4) processing a hydraulic amplifier cavity on the upper block; (5) processing two conical cylindrical pins; (6) pressing the conical cylindrical pins into the lower block; (7) pressing the processed lower block into the conical cylindrical pins in (6); and (8) detecting the pressing quality of the upper and lower blocks. The new processing method eliminates the precision machining requirement due to assembly requirement, optimizes the design process and processing technology, improves the integration degree of precision assembly parts, reduces the precision machining difficulty, and reduces the processing cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aviation hydraulic technology, and relates to a combined hydraulic amplifier manufacturing method. BACKGROUND

[0002] The hydraulic amplifier is a key component in the electro-hydraulic servo valve, and the machining and assembling precision of the hydraulic amplifier directly affects the product performance. However, the core functional components of the hydraulic amplifier are only some parts and sizes, most of the precise size requirements are to ensure the precise assembly of the components, and some parts are purely designed for assembly. The assembly quality of these parts also affects the output characteristics of the hydraulic amplifier. SUMMARY

[0003] In order to solve the above problems, the application provides a combined hydraulic amplifier manufacturing method, which effectively reduces the machining precision of the parts, eliminates the assembly process, and improves the overall performance and assembly efficiency of the hydraulic amplifier.

[0004] The technical scheme of the application is as follows:

[0005] A combined hydraulic amplifier manufacturing method comprises the following steps: (1) preparing materials; (2) machining an upper block and a lower block; (3) heat treatment; (4) machining an oil passage cavity of the hydraulic amplifier on the upper block; (5) machining two tapered cylindrical pins; (6) pressing the tapered cylindrical pins into the lower block; (7) pressing the machined upper block into the tapered cylindrical pins in step (6); (8) detecting the pressing quality of the upper block and the lower block to obtain a combined hydraulic amplifier.

[0006] Further, in step (2), a long strip-shaped oil return passage is machined on one side surface of the lower block, a circular large hole is machined on the other side surface, the circular large hole is communicated with the oil return passage, two symmetrical pin holes are machined on one side of the oil return passage; an oil inlet hole is machined on one side of the oil return passage, the oil inlet hole is located between the two pin holes; two load holes are machined on the other side of the oil return passage.

[0007] Further, in step (2), a long strip-shaped oil return passage is machined on one side surface of the upper block, a circular large hole is machined on the other side surface, the circular large hole is communicated with the oil return passage, the oil return passage on the upper block is the same in shape as the oil return passage on the lower block and corresponds in position; two symmetrical pin holes are machined on one side of the oil return passage on the upper block, the two pin holes on the upper block correspond in position to the two pin holes on the lower block.

[0008] Further, the material of the upper block is 9Cr18Mo, and the material of the lower block and the cylindrical pin is 2Cr13.

[0009] Further, in step (3), the hardness of the upper block after heat treatment is HRC58-62, and the hardness of the lower block and the cylindrical pin after heat treatment is HRC26-32.

[0010] Further, in step (4), the hydraulic amplifier oil passage is rough machined on the upper block by using the electric spark process, and then the hydraulic amplifier oil passage is finished by using the femtosecond laser process, so that the oil passage is communicated with the oil return channel on the upper block, and the fine requirement of the oil passage is ensured.

[0011] Further, the electric spark process is used to rough machine and remove 85% to 90% of the volume of the oil passage on the upper block, at this time, the oil passage is not completely communicated with the oil return channel on the upper block, and the remaining volume of the oil passage is positioned and finished by using the femtosecond laser process, so that the oil passage is communicated with the oil return channel on the upper block.

[0012] Further, the oil passage is three water droplet-shaped cavities, including one receiving port and two jet ports, the receiving port is distributed on one side of the oil return channel of the upper block, and the two jet ports are distributed on the other side of the oil return channel of the upper block.

[0013] Further, the depth tolerance of the three water droplet-shaped cavities is ±4μm.

[0014] Further, in step (6), the tapered cylindrical pin is pressed into the pin hole of the lower block, the tapered cylindrical pin is in interference fit with the pin hole of the lower block, and the taper of the tapered cylindrical pin is 2 to 4μm larger than the interference amount of the lower block; in step (7), the pin hole on the upper block is aligned with the two tapered cylindrical pins, and the upper block is pressed into the two tapered cylindrical pins, and the pin hole on the upper block is in interference fit with the tapered cylindrical pins, and the interference amount is 0.5 to 2μm.

[0015] Further, in step (8), after the upper block and the lower block are connected by the tapered cylindrical pins, the tapered cylindrical pins do not protrude from the profile surface, the quality of the two combined surfaces is detected by an optical method, and there is no diffraction phenomenon at the two combined surfaces, wherein the combined surface of the upper block and the lower block has a smoothness of not less than 0.8μm and a flatness of not less than 0.02μm.

[0016] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0017] The present application provides a combined hydraulic amplifier manufacturing method, which effectively reduces the machining precision of parts, eliminates the assembly process, improves the overall performance and assembly efficiency of the hydraulic amplifier, eliminates the precision machining requirement due to assembly requirements through a new machining method, optimizes the design process and machining process method, improves the integration degree of precision assembly parts, reduces the precision machining difficulty, and reduces the machining cost. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of material preparation;

[0019] Figure 2 is a schematic diagram of the initial structure of the lower block;

[0020] Figure 3 is the schematic diagram of the initial structure of the upper block;

[0021] Figure 4 is the schematic diagram of the rough machining of the oil passage on the upper block;

[0022] Figure 5 is the schematic diagram of the finish machining of the oil passage on the upper block;

[0023] Figure 6 is the schematic diagram of the machined conical cylindrical pin;

[0024] Figure 7 is the schematic diagram of the conical cylindrical pin being pressed into the lower block;

[0025] Figure 8 is the schematic diagram of the upper block and the lower block being connected through the conical cylindrical pin. DETAILED DESCRIPTION

[0026] The application is further described below in connection with the embodiments shown in the drawings.

[0027] A manufacturing method of a combined hydraulic amplifier, comprising the following steps:

[0028] (1) preparing materials, the blank material is selected as a cylindrical blank material, which is convenient for machining the upper block and the lower block; Figure 1

[0029] (2) machining the initial structure of the upper block and the lower block; as shown in the drawing; Figures 2-3

[0030] The lower block has a long strip-shaped oil return passage on one side surface and a circular large hole on the other side surface, the circular large hole is communicated with the oil return passage, two symmetrical pin holes are machined on one side of the oil return passage; an oil inlet hole is machined on one side of the oil return passage, the oil inlet hole is located between the two pin holes; two load holes are machined on the other side of the oil return passage.

[0031] The upper block has a long strip-shaped oil return passage on one side surface and a circular large hole on the other side surface, the circular large hole is communicated with the oil return passage, the oil return passage on the upper block is the same in shape as the oil return passage on the lower block and corresponds in position; two symmetrical pin holes are machined on one side of the oil return passage on the upper block, the two pin holes on the upper block correspond in position with the two pin holes on the lower block.

[0032] The circular hole on the upper block, the circular hole on the lower block and the long strip-shaped oil return passage all have the function of passing through the components of the armature assembly, the left and right movement of the armature assembly dynamically distributes the inlet oil into two small water droplets, and the residual part is discharged through the long strip-shaped oil return passage and the circular hole on the lower block.

[0033] ​​The lower block is connected with the components of the valve body, and the valve body also has four holes, one oil inlet hole, two load holes and one large oil return hole. The left and right movement of the armature assembly can change the size of the oil energy accepted by the load hole, so as to change the energy through the valve body to the next stage.

[0034] In addition, the material of the upper block is 9Cr18Mo, and the material of the lower block and the cylindrical pin is 2Cr13. The selection of the materials of the upper block, the lower block and the cylindrical pin can improve the service life of the product, the deformation of the interference object, and the process feasibility of the machining of the parts.

[0035] (3) heat treatment;

[0036] The traditional heat treatment method is used to eliminate internal stress and improve hardness.

[0037] The heat treatment hardness of the upper block is HRC58-62, and the heat treatment hardness of the lower block and the cylindrical pin is HRC26-32. The heat treatment hardness of the upper block, the lower block and the cylindrical pin can improve the service life of the product, the deformation of the interference object, and the process feasibility of the machining of the parts.

[0038] (4) machining a hydraulic amplifier oil passage cavity on the upper block; using electric spark technology, a hydraulic amplifier oil passage cavity is roughly machined on the upper block, and then using femtosecond laser technology, the hydraulic amplifier oil passage cavity is precisely machined, so that the oil passage cavity is communicated with the oil return channel on the upper block, and the fine requirements of the oil passage cavity are ensured.

[0039] The specific operation is: using electric spark technology, 85%-90% of the volume of the oil passage cavity is roughly machined and removed on the upper block. At this time, the oil passage cavity is not completely communicated with the oil return channel on the upper block, and the remaining volume of the oil passage cavity is positioned and precisely machined using femtosecond laser technology, so that the oil passage cavity is communicated with the oil return channel on the upper block. The precise machining of femtosecond laser can realize the machining of microstructure, eliminate machining stress, reduce deformation, and avoid the generation of burrs, shorten the process route, and avoid the secondary flat grinding process after precise machining; as shown in Figures 4-5 .

[0040] As shown in Figure 4 , 5 , the oil passage cavity is three water droplet-shaped cavities, including one receiving port and two jet ports. The receiving port is distributed on one side of the oil return channel of the upper block, and the two jet ports are distributed on the other side of the oil return channel of the upper block. Among them, the depth tolerance of the three water droplet-shaped cavities is ±4μm. Thickness is an important indicator affecting performance. As a pre-stage, it will directly affect the dynamic performance of the entire product. Different thicknesses will affect the consistency of the same batch of products or the same type of products.

[0041] (5) machining two tapered cylindrical pins; the tapered cylindrical pin is thick at one end and thin at the other end, the thick end is used for interference fit with the pin hole of the lower block, and the thin end is used for interference fit with the pin hole of the upper block;

[0042] (6) pressing the tapered cylindrical pin into the lower block; (7) pressing the machined upper block into the tapered cylindrical pin in step (6); the tapered cylindrical pin is pressed into the pin hole of the lower block, the tapered cylindrical pin has an interference fit with the pin hole of the lower block, and the taper of the tapered cylindrical pin is 2-4 μm larger than the interference amount of the lower block; in step (7), the pin hole of the upper block is aligned with the two tapered cylindrical pins, and the upper block is pressed into the two tapered cylindrical pins, the pin hole of the upper block has an interference fit with the tapered cylindrical pins, and the interference amount is 0.5-2 μm. The tapered cylindrical pins ensure different interference amounts with the upper block and the lower block, and reduce the deformation amount of the important parts.

[0043] (8) detecting the pressing quality of the upper block and the lower block to obtain the combined hydraulic amplifier. After the upper block and the lower block are connected by the tapered cylindrical pins, the tapered cylindrical pins do not protrude from the profile surface, the quality of the two joint surfaces is detected by an optical method, and there is no diffraction phenomenon at the two joint surfaces, wherein the surface finish of the upper block and the lower block is not less than 0.8 μm, and the flatness is not less than 0.02 μm. The requirements of surface finish and flatness are to ensure the combination degree of the upper block and the lower block, and to avoid performance out-of-tolerance caused by unevenness, therefore, the detection requirements are increased.

[0044] The above description of the embodiments is for the purpose of facilitating the understanding and application of the present application by those skilled in the art. Those skilled in the art can easily make various modifications to the embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the embodiments herein, and improvements and modifications made by those skilled in the art based on the disclosure of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. A method of making a combined hydraulic amplifier, comprising: The method comprises the following steps: (1) preparing materials; (2) machining upper and lower blocks; (3) heat treatment; (4) machining hydraulic amplifier oil passage on the upper block; (5) machining two tapered cylindrical pins; (6) pressing the tapered cylindrical pins into the lower block; (7) pressing the machined upper block into the tapered cylindrical pins in step (6); (8) detecting the pressing quality of the upper and lower blocks to obtain a combined hydraulic amplifier. In step (2), a long strip-shaped oil return passage is machined on one side surface of the lower block, a circular large hole is machined on the other side surface, the circular large hole is communicated with the oil return passage, two symmetrical pin holes are machined on one side of the oil return passage; an oil inlet hole is machined on one side of the oil return passage, the oil inlet hole is located between the two pin holes; two load holes are machined on the other side of the oil return passage. In step (2), a long strip-shaped oil return passage is machined on one side surface of the upper block, a circular large hole is machined on the other side surface, the circular large hole is communicated with the oil return passage, the oil return passage on the upper block is identical in shape with the oil return passage on the lower block and corresponds in position; two symmetrical pin holes are machined on one side of the oil return passage on the upper block, the two pin holes on the upper block correspond in position with the two pin holes on the lower block.

2. The method of claim 1, wherein, The material of the upper block is 9Cr18Mo, and the materials of the lower block and the cylindrical pin are 2Cr13.

3. The method of claim 1, wherein, In step (3), the hardness of the upper block after heat treatment is HRC58-62, and the hardness of the lower block and the cylindrical pin after heat treatment is HRC26-32.

4. The method of claim 1, wherein, In step (4), the hydraulic amplifier oil passage is roughly machined on the upper block by using the electric spark process, and then the hydraulic amplifier oil passage is finely machined by using the femtosecond laser process, so that the oil passage is communicated with the oil return passage on the upper block and the fine requirement of the oil passage is ensured.

5. The method of claim 4, wherein, By using the electric spark process, 85%-90% of the volume of the oil passage is removed, at this time, the oil passage is not completely communicated with the oil return passage on the upper block, and the remaining volume of the oil passage is positioned and finely machined by using the femtosecond laser process, so that the oil passage is communicated with the oil return passage on the upper block.

6. The method of claim 5, wherein, The oil passage is three water-drop-shaped cavities, including one receiving port and two jet ports, the receiving port is distributed on one side of the oil return passage on the upper block, and the two jet ports are distributed on the other side of the oil return passage on the upper block.

7. The method of claim 6, wherein, The depth tolerance of the three water-drop-shaped cavities is ±4μm.

8. The method of claim 1, wherein, In step (6), the tapered cylindrical pins are pressed into the pin holes of the lower block, the tapered cylindrical pins are in interference fit with the pin holes of the lower block, the taper of the tapered cylindrical pins is 2-4μm larger than the interference amount of the lower block; in step (7), the pin holes on the upper block are aligned with the two tapered cylindrical pins, the upper block is pressed into the two tapered cylindrical pins, the pin holes on the upper block are in interference fit with the tapered cylindrical pins, and the interference amount is 0.5-2μm.

9. The method of claim 8, wherein, In step (8), after the upper block and the lower block are connected through the tapered cylindrical pins, the tapered cylindrical pins do not protrude from the profile surface, the quality of the two combined surfaces is detected by optical method, and there is no diffraction phenomenon at the two combined surfaces, wherein the surface roughness of the combined surface of the upper block and the lower block is not less than 0.8μm, and the flatness is not less than 0.02μm.

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