A centering and fastening method and fixture for internal spline gear grinding

Abstract

The present invention discloses a centering and fastening method and fixture for internal spline gear grinding, which is to set a cam with multiple eccentric arc surfaces on a core shaft, and when clamping, the gear to be ground with internal splines is sleeved on the cam, and when the cam rotates in the internal spline hole, the spacing between any point of the internal spline and the eccentric arc surface can be changed from large to small, and an intermediate component is placed between the spline and the eccentric arc surface, and the cam is rotated to make the eccentric arc surface radially push the intermediate component outward, and when the cam cannot rotate in the internal spline hole, all the intermediate components are pressed between the internal spline and the eccentric arc surface, so as to achieve the clamping of the gear to be ground with internal splines, and ensure that the designed axis center line of the internal spline hole of the clamped gear to be ground coincides with the axis center line of the core shaft. In the structure of the present invention, the intermediate component is a roller, which has the advantages of convenient and quick clamping of the workpiece, effectively improving the processing efficiency, high clamping accuracy, and low manufacturing cost.

Description

Technical Field

[0001] The invention relates to a clamp, a centering and fastening method and a clamp used in internal spline gear grinding processing, and belongs to the field of gear processing tooling. Background Art

[0002] An internal spline gear refers to a transmission gear whose inner hole is connected to the external spline tooth surface of the transmission shaft by an involute tooth surface spline. When grinding this kind of internal spline gear, the design requires the use of internal spline tooth side centering, but it is necessary to manufacture an external spline positioning fixture that contacts the internal spline tooth surface. The precision requirements are high and the processing is very difficult. In addition, the external spline positioning expansion sleeve is in surface contact with the internal spline tooth surface of the workpiece, which is easily affected by the deformation of itself and the internal spline of the workpiece. The actual positioning accuracy that can be achieved is difficult to control. Therefore, this positioning method using an external spline expansion sleeve is rarely used.

[0003] The existing technology usually converts the positioning reference into the internal spline tooth top circle (i.e., the spline hole minor diameter) for positioning processing. This requires very high coaxiality requirements for the internal spline major diameter, minor diameter and key side processing before heat treatment, which increases the cost and difficulty of spline processing. However, due to the influence of heat treatment deformation, the coaxiality of the spline major diameter, minor diameter and key side after heat treatment varies greatly. Therefore, a step of grinding the spline inner hole (i.e., the spline minor diameter) is generally added before gear grinding. When grinding the inner hole, it is required to manually align the spline pitch circle for centering. Manual alignment is inefficient and has a large uncertainty. This method is difficult to eliminate the non-coincidence error of the reference, which is bound to affect the final product quality. Summary of the invention

[0004] The technical problem to be solved by the present invention is: when a workpiece already having an internal spline is to be processed into a gear having an internal spline by grinding the outer periphery of the workpiece, it is difficult to align and position the design axis line of the internal spline tooth top circle (i.e., the internal spline minor diameter circle) according to the design accuracy with the prior art.

[0005] In view of the above problems, the technical solution proposed by the present invention is:

[0006] A centering and fastening method for internal spline gear grinding processing is to set a cam with multiple eccentric arc surfaces on a core shaft, and when clamping, the gear to be ground with an internal spline is set on the cam, and the characteristic that the spacing between any point of the internal spline and the eccentric arc surface can change from large to small when the cam rotates in the internal spline hole is utilized, and an intermediate component is placed between the spline and the eccentric arc surface, and the cam is rotated to make the eccentric arc surface radially push the intermediate component outward, and when the cam cannot rotate in the internal spline hole, all the intermediate components are tightly pressed between the internal spline and the eccentric arc surface, thereby achieving the clamping of the gear to be ground with an internal spline, and ensuring that the designed axis center line of the internal spline hole of the clamped gear to be ground coincides with the axis center line of the core shaft.

[0007] Furthermore, by utilizing the characteristics of the healthy tooth surfaces on both sides of the internal spline tooth groove that can provide limiting features in two directions and the characteristic that the circular body can roll, the intermediate component is set to a cylindrical roller. When clamping, the roller is inserted between the tooth groove and the eccentric arc surface at the point where the distance between the eccentric arc surface of the cam and the internal spline tooth groove is the largest. When clamping, the cam is rotated so that the eccentric arc surface gradually presses the roller into the tooth groove. When the cam cannot rotate in the internal spline hole, radial clamping of the gear to be ground with an internal spline is achieved.

[0008] The method as described above also includes making the roller into an elastic body capable of bending.

[0009] The method as described above also includes making the roller into a tubular body with a through hole along the axis, and sleeved the roller on a string rod, fixing one end of the string rod on a frame; making the diameter of the through hole larger than the diameter of the string rod to ensure that when the string rod is fixed, the roller can be pushed radially toward the inner spline groove outside the cam by the eccentric arc surface.

[0010] Furthermore, the number of eccentric arc surfaces set on the outer periphery of the cam is selected to be 3 or 4, so that the diameters of all rollers are equal; for the gear to be processed whose number of internal spline teeth can be divided by the number of eccentric arc surfaces on the outer periphery of the cam, the eccentric arc surfaces on the outer periphery of the cam are set with equal arc angles and arc lengths, and the circumferential spacing of adjacent eccentric arc surfaces on the outer periphery of the cam is equal.

[0011] Furthermore, the number of eccentric arc surfaces set on the outer periphery of the cam is selected to be 3 or 4 so that the diameters of all rollers are equal. For the gear to be processed whose number of internal spline teeth cannot be divided by the number of eccentric arc surfaces on the outer periphery of the cam, one eccentric arc surface is selected as a non-equally divided eccentric arc surface among the eccentric arc surfaces on the outer periphery of the cam. When setting, the arc length and radian of the non-equally divided eccentric arc surface are adjusted so that the non-equally divided eccentric arc surface can correspond to one more or one less internal spline tooth groove radially outward compared with other eccentric arc surfaces, and when other eccentric arc surfaces have a position to clamp the roller between the corresponding internal spline tooth groove, the non-equally divided eccentric arc surface also has a position to clamp the roller between the corresponding internal spline tooth groove.

[0012] A centering and fastening fixture designed by the method as described above for use in internal spline gear grinding processing comprises a core shaft, a cam and a roller; the cam is sleeved on the core shaft, and the outer peripheral surface of the cam has multiple eccentric arc surfaces. When clamped, the cam is located in the internal spline hole of the internal spline gear to be processed, and each eccentric arc surface has a roller located between the eccentric arc surface and a tooth groove of the internal spline.

[0013] Furthermore, one end of the eccentric arc surface on the outer periphery of the cam is a proximal end close to the axis of the core shaft, and the other end is a distal end far from the axis of the core shaft; there is a connecting surface between two adjacent eccentric arc surfaces, one end of the connecting surface intersects with the distal end of one eccentric arc surface, and the other end of the connecting surface intersects with the proximal end of one eccentric arc surface.

[0014] Furthermore, the roller is a columnar spiral body with an axial through hole.

[0015] Furthermore, the gear grinding fixture also includes a retaining frame with a collar, which is sleeved on the core shaft above the cam, and a string rod extending to the outer periphery of the cam is provided below the collar facing the cam, and the roller is sleeved on the string rod.

[0016] The advantages of the present invention are:

[0017] 1. The present invention adopts a cambered cam mandrel to achieve gapless positioning of the pitch circle of the internal spline tooth side. The contact between the positioning surfaces is point-line contact, which can meet very high precision requirements.

[0018] 2. In the actual application of the present invention, the workpiece can be clamped conveniently and quickly without manual alignment, which effectively improves the processing efficiency.

[0019] 3. Compared with the spline small diameter positioning processing method, it reduces one inner hole grinding process, and does not need to use a composite broach, which reduces the manufacturing cost of the spline broach. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional schematic diagram of the fixture after clamping the internal spline gear;

[0021] Figure 2 for Figure 1 A partial schematic diagram of

[0022] Figure 3 is a schematic diagram of the mandrel and a cam integrally formed with the mandrel;

[0023] Figure 4 is a cross-sectional schematic diagram of the cam;

[0024] Figure 5 It is a cross-sectional schematic diagram after the internal spline gear is mounted on the cam, and the figure mainly shows that the roller is located between the proximal end of the eccentric arc surface and the tooth groove;

[0025] Figure 6 It is a cross-sectional schematic diagram after the internal spline gear is mounted on the cam, and the figure mainly shows that the roller is located between the distal end of the eccentric arc surface and the tooth groove;

[0026] Figure 7It is a cross-sectional schematic diagram of a cam with a non-equally divided eccentric arc surface fixing an internal spline gear by radially tightening with rollers. The figure mainly shows that the eccentric arc surface radially outwardly corresponds to 7 tooth grooves of the internal spline, while the non-equally divided eccentric arc surface radially outwardly corresponds to 8 tooth grooves of the internal spline;

[0027] Figure 8 It is a schematic diagram of the connection surface of the roller sleeve on the string rod;

[0028] Fig. 9 is a schematic diagram of a partial cross section of the retainer;

[0029] Fig.10 Schematic diagram of the cross section of the skewer installed on the collar.

[0030] In the figure: 1. core shaft; 2. cam; 21. eccentric arc surface; 211. proximal end; 212. distal end; 23. connecting surface; 24. non-uniform eccentric arc surface; 3. roller; 31. through hole; 4. retaining frame; 41. sleeve ring; 42. string rod; 5. positioning ring; 51. positioning hole one; 52. positioning hole two; 53. soft sleeve; 54. fastening pin; 6. pressure cover; 7. cross pressure frame; 8. fastening nut; 9. internal spline gear; 91. tooth groove. DETAILED DESCRIPTION

[0031] The present invention relates to a centering and fastening method and a fixture structure for internal spline gear grinding. For ease of description and understanding, the basic structure and application principle of the fixture designed according to the method of the present invention are briefly described as follows:

[0032] Basic structure: such as Figure 1 , 2 As shown in Figure 4, the clamp of the present invention includes a core shaft 1, a cam 2 sleeved on the core shaft 1, the outer peripheral surface of the cam 2 has a plurality of eccentric arc surfaces 21, below the cam 2 is a positioning ring 5 sleeved on the core shaft 1, above the cam 2 is a pressure cover 6 sleeved on the core shaft 1, above the pressure cover 6 is a cross pressure frame 7 sleeved on the core shaft 1, and above the cross pressure frame 7 is a fastening nut 8 sleeved on the core shaft 1 and threadedly matched with the core shaft 1.

[0033] The processing object of the present invention is an internal spline gear 9 having internal splines.

[0034] The processing task is to grind the outer periphery of the internal spline gear according to the design requirements.

[0035] The processing measure is to utilize the cam 2 on the core shaft 1 to expand and fix the internal spline gear 9 radially outward from the internal spline hole.

[0036] The requirement is that the axial core line of the internal spline hole of the internal spline gear 9 that is radially expanded and fixed outward is highly coincident with the axial core line of the core shaft 1, so as to ensure the grinding processing accuracy of the internal spline gear 9.

[0037] Application principle: Figure 1 , 2 As shown in , 5, when clamping, the internal spline gear 9 is mounted on the cam 2 through the internal spline hole. On each eccentric arc surface 21 on the cam 2, there is a roller 3 located between the eccentric arc surface 21 and a tooth groove 91 of the internal spline. When clamping, the cam 2 is rotated in the internal spline hole, and the roller 3 is gradually squeezed between the eccentric arc surface 21 and the tooth groove 91 by the rotating eccentric arc surface 21. When the cam 2 cannot rotate, the internal spline gear 9 is radially fastened to the cam 2, and the designed axis center line of the internal spline hole coincides with the axis center line of the core shaft 1. Obviously, the positioning ring 5 located below the cam 2 and the pressure cover 6, cross pressure frame 7 and fastening nut located above the cam 2 are used to implement axial fastening of the internal spline gear 9.

[0038] The method of the present invention is described in detail below with reference to the accompanying drawings.

[0039] like Figure 2 As shown in FIG6 , a centering and fastening method for internal spline gear grinding processing is provided, wherein a cam 2 having a plurality of eccentric arc surfaces 21 is mounted on a core shaft 1. During clamping, the gear to be ground having an internal spline is mounted on the cam 2. When the cam 2 rotates in the internal spline hole, the spacing between any point of the internal spline and the eccentric arc surface 21 can be changed from large to small. An intermediate component is placed between the spline and the eccentric arc surface 21 (in actual application, the intermediate component is first installed in the internal spline of the gear to be ground, and then mounted on the core shaft together). The cam 2 is rotated to make the eccentric arc surface 21 radially push the intermediate component outward. When the cam 2 cannot rotate in the internal spline hole, all the intermediate components are pressed between the internal spline and the eccentric arc surface 21, thereby achieving the clamping of the gear to be ground having an internal spline, and ensuring that the designed axis center line of the internal spline hole of the clamped gear to be ground coincides with the axis center line of the core shaft 1. This arrangement can achieve gapless positioning of the pitch circle of the internal spline tooth side, and the contact between the positioning surfaces is point-line contact, which can meet very high precision requirements, and the workpiece can be clamped conveniently and quickly without manual alignment, effectively improving the processing efficiency. At the same time, it reduces the common inner hole grinding process in the prior art, does not need to use a composite broach, increases the precision of the internal spline itself, and reduces the manufacturing cost of the spline broach.

[0040] The above method utilizes the characteristics that the healthy tooth surfaces on both sides of the internal spline tooth groove 91 can provide two-way limiting and the characteristic that the circular body can roll, and sets the intermediate component as a cylindrical roller 3. When clamping, the roller 3 is inserted between the tooth groove 91 and the eccentric arc surface 21 of the cam at the point where the distance between the eccentric arc surface 21 and the internal spline tooth groove 91 is the largest. When clamping, the cam 2 is rotated so that the eccentric arc surface 21 gradually presses the roller 3 into the tooth groove 91. When the cam 2 cannot rotate in the internal spline hole, the radial tightening of the gear to be ground with an internal spline is achieved.

[0041] like Fig. 9 As shown, the above method also includes making the roller 3 into an elastic body capable of bending. Such a configuration can enable the roller 3 to have better surface adaptability and can be pressed tightly into the tooth groove 91 by the eccentric arc surface 21.

[0042] like Figure 8 , 9 As shown, the above method also includes making the roller 3 into a tubular body with a through hole 31 along the axis, and sleeved the roller 3 on the string rod 42, and fixing one end of the string rod 42 on a frame; the aperture of the through hole 31 is made larger than the diameter of the string rod 42 to ensure that when the string rod 42 is fixed, the roller 3 can be pushed radially toward the inner spline groove 91 outside the cam by the eccentric arc surface 21.

[0043] like Figure 5 , 6 As shown, the above method is to select the number of eccentric arc surfaces 21 set on the outer periphery of the cam 2 to be 3 or 4, so that the diameters of all rollers 3 are equal; for the gear to be processed whose number of internal spline teeth can be divided by the number of eccentric arc surfaces 21 on the outer periphery of the cam, the eccentric arc surfaces 21 on the outer periphery of the cam 2 are set with equal arcs and equal arc lengths, and the circumferential spacing of adjacent eccentric arc surfaces 21 on the outer periphery of the cam 2 is equal. This is a very ideal situation in practical applications. Each eccentric arc surface 21 can correspond to the same number of internal spline tooth grooves 91 radially outward. In this case, the above setting can ensure that the axial core line of the internal spline hole and the axial core line of the mandrel 1 have extremely high coaxiality after clamping.

[0044] like Figure 7 As shown, for the gear to be processed whose number of internal spline teeth cannot be divided by the number of eccentric arc surfaces 21 on the outer periphery of the cam, the number of eccentric arc surfaces 21 set on the outer periphery of the cam 2 is also selected to be 3 or 4, so that the diameters of all rollers 3 are equal. The difference is that it is necessary to select one eccentric arc surface 21 from the eccentric arc surfaces 21 on the outer periphery of the cam 2 as a non-equally divided eccentric arc surface 24, and adjust the arc length and radian of the non-equally divided eccentric arc surface 24 during setting, so that the non-equally divided eccentric arc surface 24 can correspond to one more or one less internal spline tooth groove 91 radially outward compared with other eccentric arc surfaces 21 (when the number of eccentric arc surfaces on the cam 2 can be selected to be 3 or 4, there will only be a situation where one non-equally divided eccentric arc surface 24 corresponds to one more or one less tooth groove 91 radially outward, and the other eccentric arc surfaces can correspond to the same number of tooth grooves 91, such as Figure 7It is shown that the eccentric arc surface radially outwardly corresponds to 7 internal spline tooth grooves 91, while the non-equally divided eccentric arc surface radially outwardly corresponds to 8 internal spline tooth grooves 91), and when the other eccentric arc surface 21 has a position to clamp the roller 3 between the corresponding internal spline tooth groove 91, the non-equally divided eccentric arc surface 24 also has a position to clamp the roller 3 between the corresponding internal spline tooth groove 91. This situation will also be encountered in actual applications, and the above-mentioned setting is to cope with this situation. Through this method, the gear to be processed that cannot be divided by the number of eccentric arc surfaces 21 on the outer periphery of the cam can also be quickly and coaxially centered and fastened, but when making the cam 2, the non-equally divided eccentric arc surface 24 needs to be debugged and processed to achieve that when the other eccentric arc surface 21 has a position to clamp the roller 3 between the corresponding spline tooth groove 91, the non-equally divided eccentric arc surface 24 also has a position to clamp the roller 3 between the corresponding spline tooth groove 91.

[0045] The clamp structure of the present invention is described in detail below in conjunction with the accompanying drawings.

[0046] like Figure 2 , 3 As shown in Figures 4 and 5, a centering and fastening fixture for internal spline gear grinding processing designed by the above method comprises a core shaft 1, a cam 2 and a roller 3; the cam 2 is sleeved on the core shaft 1, and the outer peripheral surface of the cam 2 has a plurality of eccentric arc surfaces 21. When clamped, the cam 2 is located in the inner spline hole of the internal spline gear to be processed, and each eccentric arc surface 21 has a roller 3 located between the eccentric arc surface 21 and a tooth groove 91 of the spline. One end of the eccentric arc surface 21 on the outer periphery of the cam 2 is a proximal end 211 closer to the axis of the core shaft 1, and the other end is a distal end 212 farther from the axis of the core shaft 1; there is a connecting surface 23 between two adjacent eccentric arc surfaces 21, one end of the connecting surface 23 intersects with the distal end 212 of one eccentric arc surface 21, and the other end of the connecting surface 23 intersects with the proximal end 211 of one eccentric arc surface 21. The design is such that, during clamping, the roller 3 can be easily inserted between the eccentric arc surface 21 and the radially corresponding internal spline tooth groove 91 at the proximal end 211 of the eccentric arc surface 21 because the distance between the proximal end 211 of the eccentric arc surface 21 and the tooth groove 91 is the largest. Then, the cam 2 is rotated in the internal spline hole. Due to the restriction of the internal spline tooth groove 91, the roller 3 can only roll in situ in the tooth groove 91 under the friction force given by the rotating eccentric arc surface 21 (when the distance between the eccentric arc surface 21 and the radially corresponding internal spline tooth groove 91 is large, the roller 3 located therebetween may not rotate), so that the roller 3 rolls or slides from the proximal end of the eccentric arc surface 21 to the distal end 212 of the eccentric arc surface 21. Finally, the roller 3 is pressed by the rotating eccentric arc surface 21 between the eccentric arc surface 21 and the internal spline tooth groove 91 at the distal end 212, thereby radially expanding and fixing the internal spline gear to be processed on the cam 2.

[0047] Here are further improvements.

[0048] like Fig. 9 As shown, the roller 3 is a cylindrical spiral body with an axial through hole 31. The purpose is to make it have a certain bending elasticity, better adaptability to the contact surface during expansion, and also not produce positioning errors due to deformation and bending like rigid rollers.

[0049] like Figure 8 , 9 As shown in FIG. 10, the gear grinding fixture further includes a retainer 4, on which there is a collar 41, which is sleeved on the mandrel 1 below the cam 2, and the collar 41 is provided with a string rod 42 extending toward the outer periphery of the cam 2 below the cam 2, and the roller 3 is sleeved on the string rod 42. In this way, several rollers 3 can be placed on one frame, and all rollers 3 can be inserted between the eccentric arc surface 21 and the inner spline tooth groove 91 at one time during clamping.

[0050] like Figure 8 , 9 As shown, there is a space between the inner wall of the axial through hole 31 of the roller 3 and the outer peripheral surface of the roller 3. The advantage of this arrangement is that when the string rod 42 on the retainer is stationary, the roller 3 can be pushed by the rotating eccentric arc surface 21 between the eccentric arc surface 21 and the inner spline tooth groove 91.

[0051] like Figure 5 , 6 As shown, the number of eccentric arc surfaces 21 arranged on the outer periphery of the cam 2 is 3 or 4, and the diameters of all rollers 3 are equal. This arrangement is to reduce the number of eccentric arc surfaces 21 as much as possible, and to make the radial force points of the fastened internal spline gear as evenly distributed as possible. The equal diameters of all rollers 3 are a preferred arrangement to take further measures to ensure that the axial core line of the internal spline hole and the axial core line of the core shaft 1 are highly coincident.

[0052] For the gear to be processed whose number of internal spline teeth can be divided by the number of eccentric arc surfaces 21 on the outer periphery of the cam, the eccentric arc surfaces 21 on the outer periphery of the cam 2 are set with equal arc angles and equal arc lengths, and the circumferential spacing of adjacent eccentric arc surfaces 21 on the outer periphery of the cam 2 is equal. As described in the above method, this is a very ideal situation in practical applications. Each eccentric arc surface 21 can correspond to the same number of internal spline tooth grooves 91 radially outward. In this case, the above setting can ensure that the axial core line of the internal spline hole and the axial core line of the core shaft 1 have extremely high coaxiality after clamping.

[0053] like Figure 7As shown, for a gear to be processed whose number of internal spline teeth cannot be divided by the number of eccentric arc surfaces 21 on the outer periphery of the cam, a non-equally divided eccentric arc surface 24 is provided in the eccentric arc surface 21 on the outer periphery of the cam 2; compared with other eccentric arc surfaces 21, the non-equally divided eccentric arc surface 24 can correspond to one more tooth groove 91 or one less tooth groove 91 radially outward, and when other eccentric arc surfaces 21 have a position between the corresponding spline tooth groove 91 to clamp the roller 3, the non-equally divided eccentric arc surface 24 also has a position between the corresponding spline tooth groove 91 to clamp the roller 3. This is also explained in the aforementioned method, when the number of eccentric arc surfaces on the cam 2 can be selected as 3 or 4, there will only be a situation where one non-equally divided eccentric arc surface 24 corresponds to one more internal spline tooth groove 91 or one less internal spline tooth groove 91 radially outward, and other eccentric arc surfaces can correspond to the same number of tooth grooves 91. In actual applications, gears to be processed whose number of internal spline teeth cannot be divided by the number of eccentric arc surfaces 21 on the outer periphery of the cam may also be encountered, and the above-mentioned setting is to cope with such a situation. With such a setting, the gears to be processed whose number of internal spline teeth cannot be divided by the number of eccentric arc surfaces 21 on the outer periphery of the cam can also be fastened with high coaxiality, except that the non-equally divided eccentric arc surfaces 24 need to be debugged and processed when making the cam, so that when other eccentric arc surfaces 21 have a position to clamp the roller 3 between the corresponding spline tooth grooves 91, the non-equally divided eccentric arc surfaces 24 also have a position to clamp the roller 3 between the corresponding spline tooth grooves 91.

[0054] like Figure 2 As shown, a positioning ring 5 is sleeved on the mandrel 1 below the cam 2, and a radially arranged positioning hole 1 51 is provided on the positioning ring 5. Corresponding to the positioning hole 1 51, a positioning hole 2 52 is provided on the mandrel 1, and the aperture of the positioning hole 2 52 is larger than the aperture of the positioning hole 1 51. A soft sleeve 53 is sleeved in the positioning hole 2 52, and a fastening pin 54 is driven into the positioning hole 1 51 and the soft sleeve 53. The reason why the positioning ring is not designed as one with the mandrel is that the processability (grinding or wire cutting) of machining the cam surface during tooling manufacturing is considered. Separate processing is possible, and there is currently no suitable processing method for designing it as one. In addition, it is also convenient to replace positioning rings of different outer diameters according to different outer diameters of products. The fastening of the locating ring 5 and the core shaft 1 is carried out through the locating pin 54, and there is a soft pin 53 in the middle. This is because it is difficult to drill and ream two hard entities, so the soft pin 53 is pre-inserted into the core shaft, and then the hole of the locating ring is used as a drilling template to drill and ream the pin hole, and then the locating pin 54 is driven in, so that firm and accurate positioning can be achieved.

[0055] like Figure 3 As shown in FIG. 1 , the mandrel 1 and the cam 2 are integrally formed. This is a preferred simple arrangement, which is particularly necessary when the difference between the diameter of the cam 2 and the diameter of the mandrel is small.

[0056] The above embodiments are only used to more clearly describe the present invention and cannot be regarded as limiting the protection scope of the present invention. Any modifications in equivalent forms should be regarded as falling within the protection scope of the present invention.

Claims

1. A centering and fastening method for internal spline gear grinding, characterized in that: A cam (2) having a plurality of eccentric arc surfaces (21) is mounted on a core shaft (1). When clamping, a gear to be ground having an internal spline is mounted on the cam (2). When the cam (2) is rotated in the internal spline hole, the distance between any point of the internal spline and the eccentric arc surface (21) can be changed from large to small. An intermediate component is placed between the spline and the eccentric arc surface (21). The cam (2) is rotated so that the eccentric arc surface (21) pushes the intermediate component radially outward. When the cam (2) is rotated in the internal spline hole, the eccentric arc surface (21) is pushed radially outward. (2) When the gear cannot rotate in the internal spline hole, all the intermediate components are pressed tightly between the internal spline and the eccentric arc surface (21), thereby achieving radial fastening of the gear to be ground with the internal spline on the outer periphery of the cam (2), and ensuring that the designed axis center line of the internal spline hole of the clamped gear to be ground coincides with the axis center line of the core shaft (1); utilizing the internal spline tooth surfaces on both sides of the internal spline tooth groove (91) to provide the feature of limiting in two directions and the feature that the circular body can roll, the gear to be ground with the internal spline is radially fastened to the outer periphery of the cam (2), and ensuring that the designed axis center line of the internal spline hole of the clamped gear to be ground coincides with the axis center line of the core shaft (1); utilizing the feature that the internal spline tooth surfaces on both sides of the internal spline tooth groove (91) can provide the feature of limiting in two directions and the feature that the circular body can roll, The intermediate component is a cylindrical roller (3). When clamping, the roller (3) is inserted between the tooth groove (91) and the eccentric arc surface (21) at the position where the distance between the eccentric arc surface (21) of the cam and the internal spline tooth groove (91) is the largest. When clamping, the cam (2) is rotated so that the eccentric arc surface (21) gradually presses the roller (3) into the tooth groove (91). When the cam (2) cannot rotate in the internal spline hole, radial tightening of the gear to be ground with the internal spline is achieved. The method also includes manufacturing the roller (3) into an elastic body capable of bending; manufacturing the roller (3) into a tubular body having a through hole (31) along the axis, sleeved on a string rod (42), and fixing one end of the string rod (42) on a frame; and making the through hole (31) larger than the diameter of the string rod (42) to ensure that when the string rod (42) is fixed, the roller (3) can be pushed radially toward the inner spline tooth groove (91) outside the cam by the eccentric arc surface (21).

2. The centering and fastening method for internal spline gear grinding according to claim 1, characterized in that: The number of eccentric arc surfaces (21) arranged on the outer periphery of the cam (2) is selected to be 3 or 4, so that the diameters of all rollers (3) are equal; for a gear to be processed whose number of internal spline teeth is divisible by the number of eccentric arc surfaces (21) on the outer periphery of the cam, the eccentric arc surfaces (21) on the outer periphery of the cam (2) are arranged with equal arcs and equal arc lengths, and the circumferential spacing of adjacent eccentric arc surfaces (21) on the outer periphery of the cam (2) is equal.

3. The centering and fastening method for internal spline gear grinding according to claim 1, characterized in that: The number of eccentric arc surfaces (21) provided on the outer periphery of the cam (2) is selected to be 3 or 4 so that the diameters of all rollers (3) are equal. For a gear to be processed whose number of internal spline teeth cannot be divided by the number of eccentric arc surfaces (21) provided on the outer periphery of the cam, one eccentric arc surface (21) is selected as a non-equally divided eccentric arc surface (24) from the eccentric arc surfaces (21) provided on the outer periphery of the cam (2). When setting, the arc length and arc angle of the non-equally divided eccentric arc surface (24) are adjusted so that the non-equally divided eccentric arc surface (24) can correspond to one more or one less internal spline tooth groove (91) radially outward compared with other eccentric arc surfaces (21), and when other eccentric arc surfaces (21) have a position between them and the corresponding internal spline tooth groove (91) to clamp the roller (3), the non-equally divided eccentric arc surface (24) also has a position between them and the corresponding internal spline tooth groove (91) to clamp the roller (3).

4. A centering and fastening fixture designed according to the method of claim 1 for use in internal spline gear grinding, comprising a mandrel (1), characterized in that: It also includes a cam (2) and a roller (3); the cam (2) is sleeved on the core shaft (1); the outer peripheral surface of the cam (2) has a plurality of eccentric arc surfaces (21); when clamped, the cam (2) is located in the internal spline hole of the internal spline gear to be processed; each eccentric arc surface (21) has a roller (3) located between the eccentric arc surface (21) and a tooth groove (91) of the internal spline.

5. The centering and fastening fixture for internal spline gear grinding according to claim 4 is characterized in that: One end of the eccentric arc surface (21) on the outer periphery of the cam (2) is a proximal end (211) close to the axis of the core shaft (1), and the other end is a distal end (212) far from the axis of the core shaft (1); a connecting surface (23) is provided between two adjacent eccentric arc surfaces (21), one end of the connecting surface (23) intersects with the distal end (212) of one eccentric arc surface (21), and the other end of the connecting surface (23) intersects with the proximal end (211) of one eccentric arc surface (21).

6. The centering and fastening fixture for internal spline gear grinding according to claim 5, characterized in that: The roller (3) is a columnar spiral having an axial through hole (31).

7. The centering and fastening fixture for internal spline gear grinding according to claim 6 is characterized in that: The centering and fastening fixture also includes a retaining frame (4), the retaining frame (4) having a collar (41), the collar (41) being sleeved on the core shaft (1) above the cam (2), the collar (41) being provided with a string rod (42) extending toward the outer periphery of the cam (2) below the cam (2), and the roller (3) being sleeved on the string rod (42).

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