Internal spline self-adaptive grinder and using method

Abstract

The internal spline self-adaptive grinder comprises a grinding head and a pressing cone, one end of the hollow grinding head is provided with an external spline matched with an internal spline of a part to be machined, the grinding head is further provided with an internal conical surface matched with the pressing cone, and the diameter of the end close to the end of the grinding head is larger than that of the other end. A groove is formed between every two adjacent outer spline teeth in the axial direction so that the end of the grinding head can form a multi-petal structure, the pressing cone is arranged in an inner hole of the grinding head, and the pressing cone is provided with an outer conical face capable of being matched with the inner conical face of the grinding head. The tooth profile of the internal spline is comprehensively and uniformly ground, and the grinding problem of the internal spline is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of internal spline processing and relates to an internal spline self-adaptive grinder and a use method thereof. Background Art

[0002] One situation is that the internal splines of some mechanical parts are located deep inside the parts, and the gear shaping equipment has insufficient stroke, making it impossible to process. Another situation is that the internal splines of the parts are long, requiring a long gear shaping cutter or a long processing stroke, resulting in insufficient strength of the gear shaping cutter during the processing process, making it impossible to process. Another situation is that the parts have high hardness and toughness, making gear shaping difficult. Or due to the influence of part structure factors, gear shaping equipment, internal spline grinding equipment, etc. cannot be used for processing.

[0003] Not limited to the internal splines of the above parts, wire cutting equipment was selected for internal spline processing in on-site production. Due to the inherent characteristics of electromachining, a remelting layer formed by re-melting the discharge of electromachining will remain on the processed surface. The remelting layer has the characteristics of discontinuity, brittleness and hardness. During the use of parts, the brittle and hard remelting layer will accelerate the wear between parts, resulting in a decrease in product performance, life and reliability. In aviation oil pump products, it is required that the transmission load-bearing parts must not have a remelting layer. The internal splines of parts are such a force transmission structure. Therefore, it is necessary to remove the remelting layer from the internal splines of parts processed by electromachining methods such as wire cutting.

[0004] The internal spline of a part is composed of multiple spline tooth profiles and tooth grooves. To remove the remelted layer on the surface of the internal spline, a grinding tool similar to the internal spline comprehensive gauge is usually used. The tool is designed in a grouped form, generally divided into 3 to 5 groups, to grind the internal spline. Since the grinder is a rigid structure, there is a certain gap between each tooth of the grinder and the internal spline of the part. During the grinding process, part of the tooth profile of the grinder can often contact the internal spline tooth profile of the component, making it difficult to achieve comprehensive and uniform processing of the internal spline tooth profile of the part. During the processing, the operator needs to have rich processing experience and change the grinding tool group at any time according to the situation in order to continuously select the grinding tools of appropriate sizes from multiple groups. Such a process is difficult to operate, the remelted layer is not completely removed, and the removal thickness is uneven, making the removal of the remelted layer of the internal spline a difficult problem. Summary of the invention

[0005] Purpose of the invention: In order to solve the problems of the existing internal spline grinding tool groups, difficult processing operations, poor results, low efficiency, etc., the present invention provides a design and use method of an internal spline adaptive grinder.

[0006] The technical solution of the present invention:

[0007] An internal spline adaptive grinder includes a grinding head and a clamping cone. One end of the hollow grinding head has an external spline that matches the internal spline of the part to be processed, and also has an internal conical surface that matches the clamping cone. The diameter of one end close to the end of the grinding head is larger than that of the other end. A groove is axially provided between every two adjacent external spline teeth to form a multi-petal structure at this end of the grinding head. The clamping cone is arranged in the inner hole of the grinding head, and the clamping cone has an external conical surface that can match the internal conical surface of the grinding head.

[0008] Preferably, the groove width is less than or equal to the distance between the starting points of the involutes of two adjacent external spline teeth.

[0009] Preferably, the length of the multi-petal structure is 1 / 2 of the length of the spline inside the part.

[0010] Preferably, an empty tool groove is provided at the junction of the middle portion of the inner hole of the grinding head and the inner conical surface.

[0011] Preferably, the slot width is: (πd) / (5 to 6 times the number of teeth on the part).

[0012] Preferably, the taper of the inner conical surface is 30 degrees.

[0013] Preferably, the grinding head is threadedly connected to the pressing cone

[0014] Preferably, the length of the outer conical surface of the pressing cone is 2 / 3 of the length of the inner conical surface of the grinding head.

[0015] Preferably, the roughness of the inner conical surface is Ra0.4.

[0016] Preferably, the method for using the internal spline grinder comprises the following steps:

[0017] (1) Place the grinding head into the internal spline of the part to be processed, apply a layer of lubricating oil on the clamping cone, and screw the clamping cone into the thread of the grinding rod. Tighten the clamping cone to a certain degree of tightness with the internal spline of the part, but the grinder can still move. Tighten the lateral clamping screw.

[0018] (2) Place the gear and grinding rod into the positioning space of the grinding base. Clamp the grinding rod onto the main shaft of the grinding equipment.

[0019] (3) The operator places the center of the grinding base on the center of the main spindle head of the grinding equipment by hand, and uses a certain clockwise force to make the grinder grind the right surface of the spline inside the part. Turn on the grinding equipment and make the clamped grinding head reciprocate on the spline stroke to perform the grinding process.

[0020] (4) After the right side surface is machined, the operator applies a certain counterclockwise force to the base, causing the grinder to grind the left side surface of the spline inside the part.

[0021] The main advantages of the present invention are: the grinder can form adaptive surface contact with the internal spline of the part, and can adjust the size of the grinding tooth pitch circle, so that the internal spline tooth surface can be fully and evenly ground by using one grinder, thus solving the problem of internal spline grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the internal spline adaptive grinder of the present invention.

[0023] Figure 2 It is a schematic diagram of the structure of the grinding head.

[0024] Figure 3 It is a schematic diagram of the appearance of the spline surface and longitudinal groove on the right end of the grinding body.

[0025] Figure 4 It is a schematic diagram of the structure of the compression cone.

[0026] Figure 5 It is a schematic diagram of clockwise processing using the internal spline adaptive grinder of the present invention.

[0027] Figure 6 It is a schematic diagram of counterclockwise processing using the internal spline adaptive grinder of the present invention.

[0028] Figure 7 It is a schematic diagram of the processed workpiece. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and its working principle.

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] The features of various aspects of the embodiments of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to fully understand the present invention. However, it is obvious to those skilled in the art that the present invention can also be implemented without these specific details. The following description of the embodiments is only for a better understanding of the present invention by illustrating examples of the present invention. The present invention is not limited to any specific settings and methods provided below, but covers all product structures, any improvements, replacements, etc. of methods covered without departing from the spirit of the present invention.

[0032] In the various drawings and the following description, well-known structures and techniques are not shown to avoid unnecessarily obscuring the present invention.

[0033] like Figure 1 The internal spline adaptive grinder consists of three parts: grinding body, clamping cone and stop screw.

[0034] like Figure 2 The grinding body is a shaft-like part with a multi-petal external spline structure. The left end of the grinding body is cylindrical on the outside and internally threaded on the inside. The middle is an internal cylindrical groove. The right end of the grinding body has external splines that match the internal splines of the processed parts and a cone on the inside. Multiple axial grooves are opened between the splines on the right end of the grinding body to the cylindrical groove inside the grinding body, making the right end of the grinding body a multi-petal structure. On the left end cylinder of the grinding body, a small threaded hole is made that is perpendicular to the central axis of the grinding body and passes from the outer cylindrical surface to the internal thread for installing the stop pin.

[0035] like Figure 3 , is a schematic diagram of the external spline of the multi-petal structure at the right end of the grinding body.

[0036] like Figure 4 , is a clamping cone. The left end of the clamping cone is an external thread that matches the grinding body, the right end is an external cone surface that matches the grinding body, and the right end head is a hexagonal screw thread.

[0037] The main structural design and function description of each part are as follows:

[0038] The grinding body is made of a metal with good toughness and wear resistance. In this embodiment, 9SiCr material is selected for illustration. 9SiCr steel is an alloy tool steel with excellent hardenability and hardenability, as well as extremely high tempering stability. It can effectively eliminate network carbides and keep carbides small and evenly distributed therein, thereby helping to improve wear resistance and improve plastic deformation resistance.

[0039] After the right end of the grinding body is processed into an external spline, a longitudinal groove is opened along the axial direction of the grinding body at the root circle of each tooth, and the groove width is less than or equal to the distance between the starting points of the involute of the two external spline teeth. The longitudinal groove is opened to the inner cylindrical groove in the middle of the grinding body, so that the right end of the grinding body becomes a multi-petal spline structure. The opened groove makes the outer spline of the grinding body have a slight elasticity and a small space for left and right movement, so as to achieve the adaptive fit of the outer spline of the grinding body to the internal spline of the processed part and improve the grinding effect. At the bottom of the longitudinal groove is a circular hole structure slightly larger than the groove. The circular hole structure is used to improve the ability of the multi-petal spline to move slightly left and right and reduce the stress concentration at the root of the longitudinal groove. In the case where the root of the spline tooth of the grinding body is opened into a longitudinal groove and the top circle of the internal spline tooth of the part cannot be processed, the part is ground by a universal inner hole grinding rod.

[0040] The length of the multi-petal structure of the grinding head is designed to be 1 / 2 of the length of the internal spline of the part. If the length of the multi-petal structure of the grinding body is designed to be too long, when the multi-petal structure of the grinding head is stretched, if the head diameter of the grinding head is too large and the tail diameter is too small, the size difference will exceed the tolerance of the internal spline of the part; if the tail diameter is too small, it will not work for the grinding process. In this embodiment, the length of the internal spline of the part is 62mm ( Figure 7 ), the multi-petal structure length of the grinding head is designed to be 30mm.

[0041] Inside the right end of the grinding body, a 300-30' inner cone is machined, and the inner cone leads to the cylindrical inner groove in the middle of the grinding head. The cylindrical groove structure is designed in the middle of the grinding body, and the wall thickness of this part should be thin, which is another measure to ensure that the multi-petal spline on the right end of the grinding body has a certain radial expansion elasticity. The cone surface length of the inner hole of the multi-petal structure of the grinding body should be greater than the spline length of the outer grinding body, and the roughness of the inner cone surface is required to be Ra0.4, so that the resistance of the pressing cone is small when it rotates and presses on the inner cone surface of the grinding head.

[0042] The elasticity of the multi-petal spline grinding head is determined by the thickness of the inner cone, the wall thickness of the inner cylindrical groove, the selected material and the heat treatment state. In this embodiment, 9SiCr steel with a heat treatment hardness of 45-50HRC is used, which is slightly higher than the hardness of the processed parts. The maximum wall thickness of the multi-petal spline inner cone hole is 1.5mm, the wall thickness of the inner cylindrical groove is 1.5-2mm, and the length of the cylinder is 10mm.

[0043] The left end of the grinding body is an outer cylindrical surface, an inner threaded hole, and a small threaded hole from the outer cylindrical surface to the inner thread. The length of the outer cylinder should be enough for the operator to hold it.

[0044] The size of the pressing cone is consistent with the grinding body, and it is processed into a 30+30′0 outer cone. The roughness of the outer cone surface is required to be Ra0.4, and the length is 2 / 3 of the inner cone of the grinding head.

[0045] Processing:

[0046] 1) The operator holds the grinding body and screws the pressing cone into the grinding body, so that the pressing cone applies pressure to the grinding body conical surface, so that the spline surface of the grinding head expands radially and the spline surface of the grinding head is attached to the internal spline surface of the processed part to achieve the required fitting pressure of the grinding surface. Through trial grinding on the internal spline of the part, the spline surface of the grinding head and the internal spline surface of the processed part reach a certain pressure adaptive contact, thereby determining the position of the pressing cone. At this time, the stop pin is screwed into the grinding body to tighten the pressing cone, apply lateral pressure and position the pressing cone, and avoid the pressing cone loosening due to the rotation of the threaded part of the pressing cone during the processing.

[0047] 2) Processing with clockwise force: Since the grinder spline is slightly smaller than the part internal spline, under the action of the adaptive grinding head, for a certain spline groove, the left or right side of the part spline groove is close to the grinder during actual processing, and there is a small gap or insufficient fit on the other side. Therefore, first apply force clockwise (attached Figure 5 , 6 ): Fix the part, and while the grinder is processing in the longitudinal direction, the operator holds the part and applies a certain force in the counterclockwise direction to make the grinder stick to the clockwise surface of the part spline. The clockwise surface processing is completed.

[0048] 3) Counterclockwise force processing: While the grinder is processing in the longitudinal direction, the operator holds the part and applies a certain force in the counterclockwise direction, so that the grinder sticks to the counterclockwise surface of the part spline to complete the counterclockwise surface processing.

Claims

1. Internal spline adaptive grinder, characterized in that: It includes a grinding head and a clamping cone. One end of the hollow grinding head has an external spline that matches the internal spline of the part to be processed, and also has an inner conical surface that matches the clamping cone. The diameter of one end close to the end of the grinding head is larger than that of the other end. A groove is axially provided between every two adjacent external spline teeth to form a multi-petal structure at this end of the grinding head. The clamping cone is arranged in the inner hole of the grinding head, and the clamping cone has an outer conical surface that can match the inner conical surface of the grinding head.

2. The internal spline adaptive grinder according to claim 1, characterized in that: The groove width is less than or equal to the distance between the starting points of the involute of two adjacent external spline teeth.

3. The internal spline adaptive grinder according to claim 1, characterized in that: The length of the multi-petal structure is 1 / 2 the length of the spline inside the part.

4. The internal spline adaptive grinder according to claim 1, characterized in that: An empty tool groove is provided at the junction of the middle part of the inner hole of the grinding head and the inner cone surface.

5. The internal spline adaptive grinder according to claim 2, characterized in that: The slot width dimension is: (πd) / (5 to 6 times the number of teeth on the part).

6. The internal spline adaptive grinder according to claim 1, characterized in that: The taper of the inner cone is 30 degrees.

7. The internal spline adaptive grinder according to claim 1, characterized in that: The grinding head is threadedly connected to the pressing cone.

8. The internal spline adaptive grinder according to claim 1, characterized in that: The length of the outer cone surface of the pressing cone is 2 / 3 of the length of the inner cone surface of the grinding head.

9. The internal spline adaptive grinder according to claim 1, characterized in that: The roughness of the inner cone surface is Ra0.

4.

10. The method for using the internal spline adaptive grinder according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Place the grinding head into the internal spline of the part to be processed, and screw the clamping cone into the thread of the grinding head; tighten the clamping cone to a certain degree of tightness with the internal spline of the part, but the grinder can move; tighten the lateral clamping screw; (2) Clamp the grinding head onto the main shaft of the grinding equipment; (3) Use a certain clockwise force to make the grinder grind the right surface of the spline inside the part; turn on the grinding equipment and make the clamped grinding head reciprocate on the spline stroke to perform grinding processing; (4) After the right side surface is machined, the operator applies a certain counterclockwise force to the base, causing the grinder to grind the left side surface of the spline inside the part.

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