A machining tool for a sliding valve of a screw compressor and a machining precision control method

Abstract

The application discloses a machining tool for a slide valve of a screw compressor, which comprises a base, a slide valve mounting hole is arranged in the middle of the base, two feeding through holes are further arranged on the side of the slide valve mounting hole, and the slide valve mounting hole and the two feeding through holes overlap with each other; a waist-shaped groove for machining a side key groove is further arranged on the side of the base corresponding to the slide valve mounting hole, and the waist-shaped groove is arranged in parallel to the slide valve mounting hole. The tool can realize machining of multiple technical elements with high precision requirements in one process, reduces positioning errors in multiple processes, improves machining precision and machining efficiency, and the machining precision control method can eliminate size deviation caused by positioning errors. The application further discloses a machining precision control method for the machining tool for the slide valve of the screw compressor, and the measuring and calculating method is used to control the precision of elements with high size requirements such as pin holes, side key grooves and herringbone curved surfaces.

Description

Technical Field

[0001] This invention relates to the field of compressor component manufacturing technology, and in particular to a machining tooling and machining accuracy control method for a screw compressor slide valve. Background Technology

[0002] A slide valve is a structural component in a screw air compressor used to regulate volumetric flow rate, such as... Figure 1 , 2 As shown, the existing slide valve 1.0 has a first pin hole 1.2 that is not centered on the exhaust side end face 1.1. The pin hole has high requirements for the positional accuracy of the slide valve's outer circle, and the exhaust side end face 1.1 has high requirements for the perpendicularity of the slide valve's outer circle. A side keyway 1.3 is provided on the outer circle of the slide valve, and the side keyway 1.3 has high requirements for the positional accuracy of the slide valve's outer circle and the pin hole 1.2. The side keyway 1.3 also has high requirements for the symmetry of the slide valve's outer circle. The other end of the slide valve away from the exhaust side end face is also provided with a fan-shaped side end face 1.11, which has a fan-shaped outward protrusion 1.4. On the side of the slide valve away from the side keyway, there is a herringbone arc surface 1.5. Holes are distributed on both the herringbone arc surface 1.5 and the outer circle surface. After the slide valve is installed on the rotor seat, the holes on the herringbone arc surface and the outer circle surface of the slide valve have high alignment requirements with the holes on the rotor surface.

[0003] Because these types of slide valves have precision machining requirements in three directions—the exhaust side end face 1.1, the side keyway 1.3, and the herringbone arc surface 1.5—they must be machined in the same process to ensure the positional requirements between the features. Due to limitations in the clamping structure, difficulty in measuring the radius of the herringbone arc, and the need for accurate positioning of the outer circle, the herringbone arc surface is often left with a margin and not made to size. It is then placed in the slide valve hole of the rotor seat and machined together to solve the problem. The herringbone arc surface is made to fit together, which increases the manufacturing cost.

[0004] Alternatively, if the machining accuracy of the herringbone arc surface is guaranteed, the accuracy requirements of elements such as the keyway on the side and the pin hole on the exhaust side end face cannot be guaranteed. In particular, the attached... Figure 1 The slide valve in this paper has additional requirements on the basis of the above-mentioned slide valve processing features. Specifically, there is a second pin hole 1.42 on the end face 1.41 of the fan-shaped protrusion 1.4, which has very high requirements for the position accuracy of the outer circle of the slide valve. Furthermore, the perpendicularity of this end face to the outer circle of the slide valve is also very high, which further increases the design difficulty of the processing tooling.

[0005] For example, a slide valve tooling for a twin-screw compressor disclosed in CN202716101U includes a support base. The support base has a mounting hole on its end face. The sidewall of the mounting hole is surrounded by a first, second, and third concave cylindrical surface, and the axes of the first, second, and third cylindrical surfaces are parallel. The first cylindrical surface matches the outer edge surface of the slide valve. An axially extending limiting groove is provided on the first cylindrical surface, and a limiting block is provided in the limiting groove.

[0006] The installation hole surrounded by three cylindrical surfaces ensures the machining precision requirement of the herringbone arc surface, but this kind of tooling is still difficult to face the complex machining requirements of the multiple precision requirements, and cannot guarantee that multiple elements on the slide valve meet the design requirements. SUMMARY

[0007] In view of the problems that the slide valve tooling in the prior art mentioned in the background art is difficult to meet the machining precision requirements of multiple elements at the same time, and step-by-step machining causes difficulty in controlling precision and increases production cost, the present application provides a machining tooling for a slide valve of a screw compressor and a machining precision control method, which can realize machining of multiple high-precision technical elements in the same process, reduces positioning errors in multiple processes, improves machining precision and machining efficiency, and the machining precision control method can eliminate size deviation caused by positioning errors.

[0008] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0009] A machining tooling for a slide valve of a screw compressor, comprising a base, a slide valve mounting hole is arranged in the middle of the base, two feed-through holes are further arranged on the side of the slide valve mounting hole, and the slide valve mounting hole and the two feed-through holes overlap with each other; a waist-shaped groove for machining a side key groove is further arranged on the side of the base corresponding to the slide valve mounting hole, and the waist-shaped groove is arranged parallel to the slide valve mounting hole.

[0010] There are three non-circular holes in the middle of the base, two of the three non-circular holes in the middle of the base are used for boring the feed space of the herringbone arc, and serve as reference points for measuring the diameter of the herringbone arc, and their diameters are 0.15-0.2mm larger than the diameter of the herringbone arc drawing of the slide valve, so as to ensure that the hole wall will not be bored during the machining process. The waist-shaped groove on the side of the base is used for machining the key groove on the side of the slide valve, and can also serve as a channel for checking whether the workpiece is straight in the horizontal direction. The side of the through groove is required to be parallel to the slide valve mounting hole. The center of the slide valve can be checked whether it is parallel to the axis of the machine tool by checking the waist-shaped groove on the tooling.

[0011] Further, a counterbore is arranged on one end of the slide valve mounting hole, at least three notched half-holes are arranged on the edge of the counterbore, and the notched half-holes penetrate the counterbore. The counterbore is used to avoid the tool during machining of the end face. The three notched half-holes are used to enable the probe to measure the position of the center of the outer circle of the slide valve.

[0012] As a preferred, a pressing plate is arranged above the base, and a positioning column penetrating the slide valve mounting hole is arranged on the bottom of the pressing plate. The pressing plate is across the herringbone arc hole, and the positioning column is pressed on the outer circle of the slide valve through an aluminum pad, so as to avoid damage to the outer circle of the slide valve.

[0013] As preferred, the top of the base is further provided with a pin, which penetrates the top of the base and is connected to the slide valve by insertion. There is a positioning hole on the upper end of the base for the pin, two through holes on the upper part of the slide valve mounting hole of the base for pressing the slide valve, and two reinforcing ribs on the side of the base for fixing the pressing plate bolts and support.

[0014] Further, the base provided with a waist-shaped slot is further provided with a positioning boss on one side. The positioning boss is a machining surface protruding from the side of the through slot of the base, and the distance between it and the hole for mounting the slide valve has been accurately measured by a coordinate measuring machine. It serves as a reference for subsequent verification of the center variation of the outer circle.

[0015] The application also discloses a machining precision control method for the machining tooling of the slide valve of the screw compressor.

[0016] S1: The positions of three points 1(A), 2(A), and 3(A) on the outer circle of the slide valve are measured by the probe through the three notched half holes on the edge of the counterbore, so that the center position of the outer circle of the slide valve is found, which is recorded as A.

[0017] S2: A pin hole is machined on the fan-shaped side end surface of the slide valve, and the positions of four points 1(B), 2(B), 3(B), and 4(B) on the outer edge of the pin hole are measured by the probe after semi-precision boring of the pin hole, which is recorded as (X, Y). Then, the positions of the three points 1(A), 2(A), and 3(A) on the outer circle of the slide valve are measured again by the probe through the three notched half holes on the edge of the counterbore, so that the center position of the outer circle of the slide valve after semi-precision boring is found, which is recorded as A'. The position difference (△X, △Y) is obtained by using the points A and A' obtained by twice measurement in S1 and S2.

[0018] S3: Start precision boring of the pin hole. Before precision boring, the position deviation values △X and △Y are substituted into the position coordinates of the precision boring tool. The theoretical coordinates of the pin hole are (X, Y), the position of the semi-precision boring is (X, Y), and the position of the precision boring is (X+△X, Y+△Y). In the case that the tool length and tool mounting mode of the precision boring tool and the semi-precision boring tool are the same, the geometric precision of the machine tool has the same influence on the coordinate position of the tool tip.

[0019] S4: The pin hole on the exhaust side end surface of the slide valve is machined according to the error elimination method of S1-S3.

[0020] As preferred, the method further comprises a precision control method for machining the side key groove.

[0021] S1: After the slide valve is mounted on the machining tooling, the parallelism of the side of the tooling at 1(D) and 2(D) points to the X axis is pre-checked by using a dial gauge, and the parallelism difference △Y1=Y 1(D) - Y 2(D), the slant milling amount of Y axis is added in the coordinate of the milling program, so that the side keyway machined can ensure the parallelism with the valve shaft center;

[0022] S2: when starting the first piece debugging, the side keyway is fine-milled to the position with a margin, the probe is used to detect the positions of 1(A), 3(A) in the notch type half hole and the positions of 1(C), 2(C) on the side keyway, the Y direction coordinate Y(A) of the slide valve outer circle center A and the Y direction coordinate Y(C) of the side keyway center are obtained, the center deviation ΔY2=Y(A)-Y(C) is calculated, and then the deviation value ΔY2 is written into the machining program.

[0023] In the method, before machining the pin hole, the positions of 1(A), 2(A), 3(A) are measured first, the center position of the slide valve outer circle is determined through the three points, the pin hole is machined, and then the semi-fine boring is performed, the positions of 1(A), 2(A), 3(A) are measured again after the semi-fine boring is completed, and the center position of the slide valve outer circle after the semi-fine boring is determined, so that the center position variation deviation (ΔX, ΔY) is calculated, the positions of four points on the outer circle of the pin hole after the semi-fine boring are measured, the center (X, Y) of the pin hole is determined, and in the subsequent fine boring machining, the center position variation deviation calculated is used to correct the fine boring machining reference, so that the pin hole position is corrected to (X+ΔX, Y+ΔY) during fine boring, and in the case that the tool length and the tool mounting mode of the fine boring cutter and the semi-fine boring cutter are the same, the influence of the machine tool geometric accuracy on the coordinate position of the tool tip is the same. The positions of the two features measured by the probe can eliminate the influence of the machine tool geometric accuracy, so that the measured positions are accurate.

[0024] As preferred, the precision control method for machining the side keyway comprises the following steps:

[0025] S1: after the slide valve is installed on the machining tooling, the parallelism of the tooling side edge at 1(D), 2(D) to the X axis is pre-checked by using the dial gauge, and the parallelism difference ΔY1=Y 1(D) - Y 2(D) , the slant milling amount of Y axis is added in the coordinate of the milling program, so that the side keyway machined can ensure the parallelism with the valve shaft center;

[0026] S2: when starting the first piece debugging, the side keyway is fine-milled to the position with a margin, the probe is used to detect the positions of 1(A), 3(A) in the notch type half hole and the positions of 1(C), 2(C) on the side keyway, the Y direction coordinate Y(A) of the slide valve outer circle center A and the Y direction coordinate Y(C) of the side keyway center are obtained, the center deviation ΔY2=Y(A)-Y(C) is calculated, and then the deviation value ΔY2 is written into the machining program. (A) and the Y direction coordinate Y (C) of the side keyway center, the center deviation ΔY2=Y (A) - Y (C) is calculated, and then the deviation value ΔY2 is written into the machining program.

[0027] Pre-checking with dial indicator after fixture installation Figure Four Parallelism of fixture side edge to X axis at points 1(D), 2(D) in Fig. 1, △Y1=Y 1(D) - Y 2(D) Add the Y axis inclined milling amount △Y1 in the coordinate of the milling program, so that the machined groove can ensure parallelism with the slide valve axis. Secondly, during the first piece debugging, before the keyway is precisely milled into place, use the probe to detect points 1(A), 3(A) and 1(C), 2(C), measure the Y direction coordinates of the slide valve outer circle center and the side keyway center, and obtain the Y direction coordinates Y (A) of the slide valve outer circle center A and the Y direction coordinates Y (C)， of the side keyway center, and calculate the center deviation △Y2=Y (A) - Y (C) Then write this deviation value into the machining program. In this way, the keyway position can be ensured to be accurate.

[0028] As a preferred embodiment, the precision control method for machining the herringbone arc surface comprises the following steps:

[0029] S1: Measure the position A of the slide valve outer circle center according to points 1(A), 2(A) and 3(A), and measure the position of the positioning boss 5(F) point, calculate the distance AF between them; measure the distance A′′F from the slide valve mounting hole center A′′ of the base to the positioning boss 5(F), and calculate the slide valve exhaust side outer circle center installation deviation △af=A′′F- AF, and write △af into the machining program;

[0030] S2: Determine the Z direction coordinate Z 1(E) of point 1(E) on the slide valve outer circle close to the exhaust side end face, and determine the Z direction coordinate Z 2(E) of the corresponding point 2(E) on the slide valve outer circle center line, point 2(E) corresponds to point 1(E), and calculate the Z direction coordinate difference value: △e=Z 2(E) -Z 1(E); then according to the above parameters, the boring tool center point (X0, Y0) coordinates are corrected when the herringbone camber is bored, wherein the boring tool feeds from the exhaust side end face to the sector side end face, the start point coordinate of the center boring tool in the X direction is corrected to X0+△af, and the end point coordinate of the center boring tool in the X direction is corrected to X0+△af-△e*W2 / W1, wherein W1 is the distance between point 1 (E) and point 2 (E), and W2 is the distance between the exhaust side end face and the sector side end face of the spool. The processing of the herringbone camber is the difficulty of the process method, and the installation deviation of the center of the outer circle of the two ends of the spool in the X axis direction can be replaced by the value of△e*W2 / W1. The value is positive or negative, and the positive value indicates that the center of the sector side circle is more deviated to the negative direction of the X axis than the center of the exhaust side circle. According to the above calculation, when the two circles of the herringbone camber are bored, the start point (exhaust side end face) coordinate of the hole center in the X direction is added to the theoretical value by△af, and the end point (sector side end face) coordinate is added to the theoretical value by△af-△e*W2 / W1. Thus, the installation error of the center axis of the spool and the Z axis of the machine tool in the X direction is compensated. Because the lower side of the mounting hole of the base of the spool is parallel to the Z axis, and the cylindricity of the outer circle of the spool is very small, the center of the spool is also parallel to the Z axis in the vertical direction. Therefore, the position of the herringbone camber bored in this way is very accurate.

[0031] Therefore, the present application has the following beneficial effects: (1) the tooling can realize the processing of multiple high-precision technical elements in the same process, reducing the positioning error of multiple process machining, improving the machining precision and machining efficiency, and the machining precision control method can eliminate the size deviation caused by the positioning error; (2) the installation error during the processing of the pin hole is corrected by double measurement before and after fine boring, improving the machining precision; (3) the deviation value of the outer circle center of the spool at the two ends in the X direction is obtained by measurement and calculation, the boring tool is corrected, the size of the herringbone camber bored is ensured to be accurate, and the influence of the installation error is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a first shaft side view of the spool in the background art.

[0033] Figure 2 It is a second shaft side view of the spool in the background art.

[0034] Figure 3 It is a structural schematic view of the present application.

[0035] Figure 4 It is a sectional view of the present application.

[0036] Figure 5 It is a processing front view of the first pin hole on the spool in Example 2.

[0037] Figure 6 It is a processing side view of the side surface key groove on the spool in Example 3.

[0038] Figure 7This is a front view of the machining of the keyway on the upper side of the slide valve in Example 3.

[0039] Figure 8 This is a front view of the machining of the herringbone arc surface on the slide valve in Example 4.

[0040] Figure 9 This is a side view of the machining of the herringbone arc surface on the slide valve in Example 4.

[0041] In the figure: spool valve 1.0, exhaust side end face 1.1, first pin hole 1.2, side keyway 1.3, fan-shaped side end face 1.11, fan-shaped protrusion 1.4, protrusion end 1.41, second pin hole 1.42, herringbone arc surface 1.5, base 100, infeed through hole 200, spool valve mounting hole 1, countersunk hole 11, notched half hole 12, waist-shaped groove 2, pressure plate 3, positioning post 31, pin 4, positioning boss 5. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0043] Example 1

[0044] like Figure 3 As shown in Figure 4, a machining fixture for a screw compressor slide valve includes a base 100. A slide valve mounting hole is provided in the middle of the base. Two infeed through holes 200 are also provided on the side of the slide valve mounting hole 1. The slide valve mounting hole and the two infeed through holes overlap each other. A waist-shaped groove 2 for machining a side keyway is also provided on the side of the base corresponding to the slide valve mounting hole. The waist-shaped groove is parallel to the slide valve mounting hole.

[0045] The base has three non-circular holes in the center. Two of these holes are used for the feed space when boring the herringbone arc and serve as reference points for measuring the diameter of the herringbone arc. Their diameters are 0.15~0.2mm larger than the diameter of the herringbone arc in the spool valve drawing to ensure that the hole wall is not bored during machining. The oblong groove on the side of the base is used for machining the keyway on the side of the spool valve and can also be used as a probe to check whether the workpiece is horizontally aligned. The side of the through groove must be parallel to the spool valve mounting hole. The alignment of the spool valve center with the machine tool axis can be checked by inspecting the oblong groove on the fixture.

[0046] A countersunk hole 11 is provided at one end of the slide valve mounting hole, and at least three notched semi-holes 12 are provided along the edge of the countersunk hole, the notched semi-holes penetrating through the countersunk hole. A pressure plate is provided above the base, and a positioning pin is provided at the bottom of the pressure plate, penetrating to the slide valve mounting hole. A pin is also provided at the top of the base, the pin penetrating the top of the base and engaging with the slide valve.

[0047] The countersunk hole is used to avoid the cutting tool when machining the end face. The three notched half-holes are for the probe to measure the position of the outer circle center of the slide valve. The pressure plate 3 spans the herringbone arc hole, and the positioning post 31 is pressed onto the outer circle of the slide valve by an aluminum pad, which can prevent the outer circle of the slide valve from being damaged. There is a positioning hole for the pin 4 at the upper end of the base, and there are two through holes for pressing the slide valve above the slide valve mounting hole on the base. There are two reinforcing ribs on the side of the base for fixing the pressure plate bolts and supports. The pressure plate spans the two holes and can press down on the outer circle of the slide valve. The side of the base with the waist-shaped groove is also provided with a positioning boss 5. The positioning boss is a machined surface protruding from the side of the base through groove. The distance between the positioning boss and the hole for mounting the slide valve has been accurately measured by a coordinate measuring machine. It serves as a reference for subsequent verification of the change in the outer circle center.

[0048] Example 2

[0049] like Figure 5 As shown, in this embodiment, this application also discloses a method for controlling the machining accuracy of the machining fixture for the above-mentioned screw compressor slide valve, including a method for controlling the accuracy of machining pin holes:

[0050] S1: Use the probe to measure the positions of three points 1(A), 2(A), and 3(A) on the outer circle of the slide valve through the three notched half-holes on the edge of the countersunk hole. Then, use the above three points to find the center position of the outer circle of the slide valve, which is denoted as A.

[0051] S2: Machining a pin hole on the fan-shaped side end face of the slide valve. After semi-finish boring the pin hole, use a probe to measure the positions of four points 1(B), 2(B), 3(B), and 4(B) on the outer edge of the pin hole, and record them as (X,Y). Then, use the probe again to measure the positions of three points 1(A), 2(A), and 3(A) on the outer circle of the slide valve through the three notched half holes on the edge of the countersunk hole, so as to find the position of the center of the outer circle of the slide valve after semi-finish boring, and record it as A′. Use the points A and A′ obtained from the two measurements in S1 and S2 to obtain the position difference (△X,△Y).

[0052] S3: Begin precision boring of the pin hole. Before precision boring, substitute the position deviation values ​​△X and △Y into the position coordinates of the precision boring tool. The theoretical coordinates of the pin hole are (X,Y). Therefore, the position of the semi-precision boring is (X,Y), and the position of the precision boring is (X+△X,Y+△Y). When the tool length and tool mounting method of the precision boring tool and the semi-precision boring tool are the same, the machine tool geometric accuracy has the same effect on the coordinate position of the tool tip.

[0053] S4: Machin the pin hole on the exhaust side end face of the slide valve according to the error elimination methods of S1-S3.

[0054] In this method, before machining the pin hole, the positions of three points 1(A), 2(A), and 3(A) are measured to determine the center position of the outer circle of the slide valve. Then, the pin hole is machined, followed by semi-finish boring. After semi-finish boring, the positions of three points 1(A), 2(A), and 3(A) are measured again to determine the center position of the outer circle of the slide valve after semi-finish boring, thereby calculating the center position deviation (△X, △Y). By measuring the positions of four points on the outer circle of the pin hole after semi-finish boring, the center of the pin hole (X, Y) is determined. In the subsequent finish boring, the calculated center position deviation is used to correct the finish boring datum, so that the pin hole position is corrected to (X+△X, Y+△Y). When the tool length and tool mounting method of the finish boring tool and the semi-finish boring tool are the same, the influence of the machine tool geometric accuracy on the coordinate position of the tool tip is the same. Measuring the position of two features with a probe can eliminate the influence of machine tool geometric accuracy, resulting in accurate position measurements.

[0055] Example 3

[0056] like Figure 6 As shown in Figure 7, this embodiment discloses a method for controlling the precision of machining side keyways:

[0057] S1: After the slide valve is installed on the machining fixture, use a dial indicator to check the parallelism of the fixture side at points 1(D) and 2(D) with respect to the X-axis, and calculate the parallelism difference ΔY1=Y 1(D) - Y 2(D) Add a slant milling amount △Y1 to the Y-axis coordinate system in the milling program. This ensures that the machined side keyway is parallel to the valve shaft.

[0058] S2: When starting the first piece debugging, leave a margin before the side keyway is finished milled. First, use a probe to detect the positions of points 1(A) and 3(A) in the notch-type half hole, and the positions of points 1(C) and 2(C) on the side keyway, to obtain the Y-coordinate of the outer circle center A of the slide valve. (A) Y-coordinate of the center of the side keyway (C) Calculate the center deviation ΔY2 = Y (A) - Y (C) Then, the deviation value △Y2 is written into the machining program.

[0059] Use a dial indicator to check before tooling installation. Figure 6 The parallelism of the tooling side at points 1(D) and 2(D) to the X-axis is given by ΔY1=Y. 1(D) - Y 2(D)To ensure the parallelism between the machined groove and the valve shaft, add a Y-axis helical milling amount △Y1 to the coordinate system of the milling program. Secondly, during the first piece debugging, before the keyway is finished milled to its final position, use a probe to check for any remaining allowance. Figure Four By measuring points 1(A), 3(A), 1(C), and 2(C), the Y-coordinate of the center of the outer circle of the slide valve and the Y-coordinate of the center of the keyway on the side are obtained, thus determining the Y-coordinate of the center A of the outer circle of the slide valve. (A) Y-coordinate of the center of the side keyway (C) Calculate the center deviation ΔY2=Y (A)- Y (C) Then, this deviation value is written into the machining program. This ensures the accurate positioning of the keyway.

[0060] Example 4

[0061] like Figure 8 , 9 As shown, this embodiment includes a method for controlling the precision of machining herringbone curved surfaces:

[0062] S1: Measure the position A of the outer circle center of the slide valve based on points 1(A), 2(A) and 3(A), and simultaneously measure the position of the positioning boss 5(F), and calculate the distance AF between them; measure the distance A′′F from the center A′′ of the slide valve mounting hole of the base to the positioning boss 5(F), and calculate the installation deviation △af = A′′F - AF of the outer circle center of the slide valve exhaust side, and write △af into the machining program;

[0063] S2: Determine the Z-coordinate of point 1 (E) on the outer circle of the slide valve, which is close to the exhaust side end face. 1(E) Then determine the Z-coordinate of point 2 (E) on the center line of the outer circle of the slide valve. 2(E) Point 2 (E) corresponds to point 1 (E), and the difference in the Z-coordinates of the two points is calculated: △e = Z 2(E) -Z 1(E) Next, based on the above parameters, correct the coordinates of the boring tool center point (X0, Y0) when boring the herringbone arc surface. The boring tool feeds from the exhaust side end face to the fan-shaped side end face. The starting coordinates of the center boring tool point in the X direction are corrected to X0 + △af, and the ending coordinates of the center boring tool point in the X direction are corrected to X0 + △af - △e * W2 / W1, where W1 is the distance between point 1 (E) and point 2 (E), and W2 is the distance between the exhaust side end face and the fan-shaped side end face of the slide valve. For example... Figure 4The machining of the chevron surface is a difficulty of the process method, and the installation deviation of the outer circle center of the spool at both ends in the X-axis direction can be replaced by the value of Δe*W2 / W1, which can be positive or negative. A positive value indicates that the center of the side circle is more deviated to the negative direction of the X-axis than the center of the exhaust side circle. According to the above calculation, when boring the two circles of the chevron, the X-direction starting point (the exhaust side end surface) coordinate of the hole center is added to the theoretical value by Δaf, and the terminal point (the side surface of the fan) coordinate is added to the theoretical value by Δaf-Δe*W2 / W1, so as to compensate for the installation error of the spool center axis and the machine tool Z-axis in the X direction. Because the lower side of the spool mounting hole of the base is parallel to the Z-axis, and the cylindricity of the outer circle of the spool is very small, the center of the spool is also parallel to the Z-axis in the vertical direction, so the position of the chevron bored in this way is very accurate. In this embodiment, the theoretical coordinate of the center of the chevron surface is (X0, Y0), and the hole boring program segment can be as follows:

[0064] G0X[X0+△af] Y0

[0065] G0Z3.

[0066] G1X[X0+△af-△e*W2 / W1]Y0Z[-W2-3.]

[0067] After boring, when measuring the diameter of the chevron on the exhaust side with a gauge, if the diameter of the tooling hole is d, and the value measured by the gauge is L, then the actual diameter of the chevron circle is: 2*(L-d / 2-△af), and the diameter of the chevron circle measured on the side of the fan is: 2*(L-d / 2-△af+△e*W2 / W1).

[0068] When machining the exhaust side end surface and the side surface of the fan, as known from the above, the center of the spool is parallel to the Z-axis in the Y direction after installation, and has a deviation of Δe*W2 / W1 in the X direction. If the width of the end surface in the X direction is K, then the deviation of the spool axis in the X direction is reflected on the end surface as Δe*K / W1, which is not perpendicular. When milling the end surface, the Z-axis coordinate can be adjusted according to the X position of the milled end surface (i.e., the XYZ three-axis linkage machining of the milled end surface), so as to compensate for the clamping error and ensure the perpendicularity of the end surface to the outer circle.

[0069] The above tooling structure enables the high-requirement features of the spool to be machined in one process, reduces the positioning error of multiple processes, and improves the machining precision and efficiency. The above machining control method eliminates the deviation caused by the positioning error, so that the machined spool can meet the precision requirements of the drawing.

[0070] In addition to the above-mentioned embodiments, within the scope disclosed by the claims and specification of the present application, the technical features of the present application can be reselected and combined to constitute new embodiments, which can be realized by those skilled in the art without creative labor, and therefore these embodiments of the present application which are not described in detail should be considered as specific embodiments of the present application and within the protection scope of the present application.

Claims

1. A machining fixture for a screw compressor slide valve, characterized in that, The device includes a base, a slide valve mounting hole in the center of the base, and two feed holes on the side of the slide valve mounting hole, which overlap with each other. A waist-shaped groove for machining a side keyway is also provided on the side of the base corresponding to the slide valve mounting hole, and the waist-shaped groove is parallel to the slide valve mounting hole. A countersunk hole is provided at one end of the slide valve mounting hole, and at least three notched semi-holes are provided along the edge of the countersunk hole, which penetrate the countersunk hole.

2. The machining fixture for a screw compressor slide valve according to claim 1, characterized in that, The countersunk hole is used to avoid the cutting tool when machining the end face.

3. The machining fixture for a screw compressor slide valve according to claim 2, characterized in that, A pressure plate is provided above the base, and a positioning post is provided at the bottom of the pressure plate, extending through to the mounting hole of the slide valve.

4. The machining fixture for a screw compressor slide valve according to claim 3, characterized in that, The base is also provided with a pin at the top, which passes through the top of the base and is inserted to connect to the slide valve.

5. The machining fixture for a screw compressor slide valve according to claim 4, characterized in that, The base has a positioning boss on one side where the waist-shaped groove is provided.

6. A method for controlling the machining accuracy of a machining fixture for a screw compressor slide valve according to any one of claims 1-5, characterized in that, Including methods for controlling the precision of machining pin holes: S1: Use the probe to measure the positions of three points 1(A), 2(A), and 3(A) on the outer circle of the slide valve through the three notched half-holes on the edge of the countersunk hole. Then, use the above three points to find the center position of the outer circle of the slide valve, which is denoted as A. S2: Machining a pin hole on the fan-shaped side end face of the slide valve. After semi-finish boring the pin hole, use a probe to measure the positions of four points 1(B), 2(B), 3(B), and 4(B) on the outer edge of the pin hole, and record them as (X,Y). Then, use the probe again to measure the positions of three points 1(A), 2(A), and 3(A) on the outer circle of the slide valve through the three notched half holes on the edge of the countersunk hole, so as to find the position of the center of the outer circle of the slide valve after semi-finish boring, and record it as A′. Use the points A and A′ obtained from the two measurements in S1 and S2 to obtain the position difference (△X,△Y). S3: Begin precision boring of the pin hole. Before precision boring, substitute the position deviation values ​​△X and △Y into the position coordinates of the precision boring tool. The theoretical coordinates of the pin hole are (X,Y). Therefore, the position of the semi-precision boring is (X,Y), and the position of the precision boring is (X+△X,Y+△Y). When the tool length and tool mounting method of the precision boring tool and the semi-precision boring tool are the same, the machine tool geometric accuracy has the same effect on the coordinate position of the tool tip. S4: Machin the pin hole on the exhaust side end face of the slide valve according to the error elimination methods of S1-S3.

7. The method for controlling the machining accuracy of a machining fixture for a screw compressor slide valve according to claim 6, characterized in that, Including precision control methods for machining side keyways: S1: After the slide valve is installed on the machining fixture, use a dial indicator to check the parallelism of the fixture side at points 1(D) and 2(D) with respect to the X-axis, and calculate the parallelism difference ΔY1=Y 1(D) - Y 2(D) Add a slant milling amount △Y1 to the Y-axis coordinate system in the milling program. This ensures that the machined side keyway is parallel to the valve shaft. S2: When starting the first piece debugging, leave a margin before the side keyway is finished milled. First, use a probe to detect the positions of points 1(A) and 3(A) in the notch-type half hole, and the positions of points 1(C) and 2(C) on the side keyway, to obtain the Y-coordinate of the outer circle center A of the slide valve. (A) Y-coordinate of the center of the side keyway (C) Calculate the center deviation ΔY2 = Y (A) - Y (C) Then, the deviation value △Y2 is written into the machining program.

8. The method for controlling the machining accuracy of a machining fixture for a screw compressor slide valve according to claim 6, characterized in that, Including precision control methods for machining herringbone curved surfaces: S1: Measure the position A of the outer circle center of the slide valve based on points 1(A), 2(A) and 3(A), and simultaneously measure the position of the positioning boss 5(F), and calculate the distance AF between them; measure the distance A′′F from the center A′′ of the slide valve mounting hole of the base to the positioning boss 5(F), and calculate the installation deviation △af = A′′F - AF of the outer circle center of the slide valve exhaust side, and write △af into the machining program; S2: Determine the Z-coordinate of point 1 (E) on the outer circle of the slide valve, which is close to the exhaust side end face. 1(E) The Z-coordinate of point 2 (E) corresponding to point 11 (E) on the centerline of the outer circle of the valve is Z. 2(E) And calculate the Z-coordinate difference between the two points: △e = Z 2(E) -Z 1(E) Next, the coordinates of the boring tool center point (X0, Y0) when boring the herringbone arc surface are corrected according to the above parameters. The boring tool feeds from the exhaust side end face to the fan-shaped side end face. The starting coordinate of the center boring tool point in the X direction is corrected to X0 + △af, and the ending coordinate of the center boring tool point in the X direction is corrected to X0 + △af - △e * W2 / W1, where W1 is the distance between point 1 (E) and point 2 (E), and W2 is the distance between the exhaust side end face and the fan-shaped side end face of the slide valve.

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