Inner ball cage spline hole broaching anti-oscillation positioning device

Abstract

This invention relates to the field of broaching positioning fixtures, specifically to a broaching anti-sway positioning device for internal ball cage spline holes. It includes a worktable, a fixed base, and a support platform. The fixed base and the support platform together form a coaxial, through-type central tool passage. A support groove is formed on the support platform. A differential anti-sway assembly consisting of three pressure ring units is installed within the support groove. Each pressure ring unit can independently move slightly downward under axial guidance and limit, and drives the corresponding anti-sway positioning block to move radially inward through an inclined push surface. When the internal ball cage exhibits a swaying tendency, the pressure ring unit at the position with the larger axial load activates first, forming a larger radial anti-sway support at that position. After the pressure ring unit reaches its set stroke, the subsequent load is transferred to the support platform by a bearing shoulder to limit over-clamping. This invention balances clamping convenience, broaching stability, and unloading / resetting reliability.

Description

Technical Field

[0001] This invention relates to the field of broaching positioning fixtures, and more particularly to a broaching anti-sway positioning device for internal ball cage spline hole broaching. Background Technology

[0002] Inner ball cage type parts usually need to be machined with spline holes in the center hole. When broaching spline holes, the workpiece is generally placed on the broaching machine table or fixture support. The broaching tool passes through the workpiece along the axis of the center hole. Under the combined action of broaching axial load, the gradual cutting resistance of the cutting teeth, the slight unevenness of the blank end face, and the peripheral positioning error, the workpiece is prone to slight wobble around the support point. If the wobble is not limited in time, it will cause the spline hole center line to deviate from the workpiece's predetermined datum, and further lead to uneven tooth profile stress, reduced broaching surface quality, and increased local wear of the cutting tool.

[0003] Existing technologies also include fixtures for internal spline broaching or internal ball cage positioning. For example, Chinese patent document CN208391141U, entitled "A Structure of a Secondary Positioning Broaching Fixture for Internal Spline," discloses a structure including a reference block, a pusher plate, a first positioning pin, a second positioning pin, a pre-positioning plate, a set screw, and a stripping cylinder. It mainly utilizes positioning pins and broach correction to achieve secondary positioning of the internal spline, which can improve operational safety and positioning convenience. However, its focus is on secondary positioning and feeding correction. For the dynamic sway of the internal ball cage caused by changes in axial load and uneven local force during broaching, it still mainly relies on preset positioning and rigid constraints, making it difficult to actively enhance the anti-sway force on the corresponding side according to the sway direction in the early stage of sway.

[0004] Furthermore, while ordinary three-jaw clamps, spring clamps, or sliding fixtures can clamp the outer periphery of the workpiece, their clamping force is usually set once before machining. If the clamping force is too small, the workpiece may still swing when the broaching load increases. If the clamping force is too large, the workpiece may be deformed or offset due to the presence of spherical, stepped, or local irregular surfaces on the outer periphery of the inner ball cage. At the same time, three-point clamping usually requires a high degree of synchronization between the clamping points. When the force on one side increases first, traditional structures cannot convert this force difference into an instant anti-sway action on the corresponding side, making it difficult to balance clamping stability and clamping convenience.

[0005] Therefore, there is an urgent need to provide a new anti-slip positioning device for broaching internal ball cage spline holes, so that it no longer relies solely on preset clamping force or repeated manual correction, but uses the axial load inherent in the broaching process as a trigger source to convert the local axial force difference under the workpiece slippage tendency into a local radial anti-slip clamping force. In this way, while keeping the structure simple, it improves the anti-slip capability, positioning consistency and operation convenience during broaching of internal ball cage spline holes. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to solve the problem that in the prior art, the inner ball cage is prone to swaying due to axial swaying load and uneven local force during spline hole broaching, and the traditional preset clamping structure is difficult to adaptively enhance the anti-swaying force according to the swaying direction. Therefore, an anti-swaying positioning device for spline hole broaching of inner ball cage is proposed.

[0007] To achieve the above objectives, the present invention provides an anti-sway positioning device for broaching spline holes in an inner ball cage, comprising a worktable, a fixed base, and a support platform.

[0008] The fixed base is connected to the coaxial hole section on the support platform to form a central tool passage for the broaching tool to pass through, and a support groove for supporting the lower end face of the inner ball cage is formed on the support platform.

[0009] The support platform slides with the fixed seat through the axial guide part, so that the support platform can only make a small displacement along the axial direction of the central tool passage.

[0010] The support groove is provided with a differential anti-sway assembly. The differential anti-sway assembly has multiple pressure ring units arranged circumferentially and capable of bearing local axial loads respectively. Each pressure ring unit can independently move slightly downward axially relative to the support platform.

[0011] The support platform is equipped with radial anti-sway components that correspond one-to-one with each pressure ring unit. Each radial anti-sway component is used to convert the axial displacement of the corresponding pressure ring unit into radial contact displacement, so that when the inner ball cage has a tendency to sway, the circumferential position with a larger axial load will preferentially increase the radial contact amount of the corresponding position.

[0012] Preferably, the axial guide portion includes guide posts spaced apart circumferentially and guide holes that slide with the guide posts. A floating support surface is provided on the fixed seat, and a reset elastic element is provided between the fixed seat and the support platform. The reset elastic element is used to push the support platform to reset along the axial guide portion after the axial tensile load is released.

[0013] Preferably, the support groove is an annular groove arranged around the central through-channel, and the differential anti-sway assembly has a three-lobed pressure ring disposed in the support groove. The three-lobed pressure ring is composed of three pressure ring units distributed circumferentially and a flexible connecting bridge connecting adjacent pressure ring units.

[0014] Preferably, each pressure ring unit is movably connected to the support platform through a guide limiting member. The guide limiting member passes through the corresponding pressure ring unit axially and is connected to the support platform. An axial movement gap is reserved between the head of the guide limiting member and the pressure ring unit to allow the pressure ring unit to move down slightly independently and to limit its radial movement and circumferential misalignment.

[0015] Preferably, each pressure ring unit has a first inclined push surface at its lower part, the radial anti-sway assembly has a radial guide groove and an anti-sway positioning block, the anti-sway positioning block has a second inclined push surface that cooperates with the first inclined push surface, and the anti-sway positioning block has a contact surface on the side facing the central through-channel, the effective contact center of the contact surface is higher than the axial support contact surface of the pressure ring unit.

[0016] Preferably, each pressure ring unit is provided with a bearing shoulder at the bottom, and a rigid bearing surface is provided on the support platform opposite to the bearing shoulder; the pressure ring unit drives the anti-sway positioning block to move radially inward through the inclined push surface during the initial downward stroke, and after reaching the set stroke, the bearing shoulder abuts against the rigid bearing surface, so that the subsequent increased axial load bypasses the inclined push surface and is transmitted to the support platform.

[0017] Preferably, a limiting shoulder is provided on the support platform, and a tension reset member is connected between the anti-sway positioning block and the limiting shoulder located on its radial outer side. When the anti-sway positioning block moves radially inward, the tension reset member stores energy, and after the axial load is released, the tension reset member pulls the anti-sway positioning block outward.

[0018] Preferably, the upper surfaces of the three pressure ring units are detachably provided with segmented replaceable support pads, and each segmented replaceable support pad is limited to the corresponding pressure ring unit by an anti-rotation key, with a differential gap reserved between adjacent segmented replaceable support pads.

[0019] Preferably, the fixed base is provided with a chip removal groove that communicates with the central tool passage; the three-lobed pressure ring is integrally formed from spring steel, and the axial thickness of the flexible connecting bridge is less than the axial thickness of the pressure ring unit, so as to reduce the constraint on the independent downward movement of each pressure ring unit while limiting circumferential misalignment.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention sets three pressure rings in the support groove and allows each pressure ring unit to independently drive the corresponding anti-sway positioning block to move radially through the inclined push surface. It can utilize the axial load that exists during the broaching process to form a force-increasing contact with the load. When clamping, the anti-sway positioning block is in a retracted or lightly contacted state. When the broaching load increases, the radial support force increases accordingly, thus taking into account both clamping convenience and processing stability.

[0022] 2. The present invention causes the three pressure ring units to move slightly downward axially under the constraint of the guide limiter. When the inner ball cage has a tendency to swing, the circumferential position with greater force can preferentially drive the corresponding anti-sway positioning block to move inward, so that the swing side forms a larger radial anti-sway support. The radial anti-sway support and the axial support contact surface form a height difference, thereby generating an anti-sway torque to counteract the swing tendency.

[0023] 3. The present invention, through the cooperation of the axial guide, guide limiter, tension reset member and bearing shoulder, enables the support platform to maintain coaxial axial floating and each pressure ring unit to maintain independent differential response. After the anti-sway positioning block reaches the set contact stroke, the subsequent axial load is directly transferred to the support platform, thereby reducing the risk of over-clamping, inclined self-locking and pressure ring unit overload, and improving the consistency and reset reliability of batch broaching positioning. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0025] Figure 1 This is a three-dimensional structural diagram of the positioning device proposed in this invention installed on a workbench.

[0026] Figure 2 This is an exploded structural diagram of the fixed base, support platform, three-lobed pressure ring, and radial anti-sway assembly proposed in this invention.

[0027] Figure 3 This is a top view of the support platform proposed in this invention, showing the support groove, the central tool passage, and the radial guide groove.

[0028] Figure 4 This is a cross-sectional view of the positioning device proposed in this invention when it is not subjected to tensile load.

[0029] Figure 5 This is a partially enlarged structural diagram of the pressure ring unit, the first inclined push surface, the anti-sway positioning block, and the second inclined push surface proposed in this invention.

[0030] Figure 6 This is a schematic diagram of the clamping state of the positioning device proposed in this invention under normal axial tensile load.

[0031] Figure 7 This is a schematic diagram of the differential anti-sway state of the positioning device proposed in this invention when the support platform remains coaxial and the sway-side pressure ring unit moves downward preferentially.

[0032] Figure 8 This is a force diagram illustrating the conversion of axial load into radial anti-sway force proposed in this invention, where arrows indicate the directions of axial load, radial anti-sway force, and anti-sway torque.

[0033] Figure 9 This is a schematic diagram showing the positional structure of the optional split-type replaceable support pad and anti-rotation key of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 100. Workbench;

[0036] 110. Fixed base; 111. Center tool passage; 112. Chip removal groove;

[0037] 120. Support platform; 121. Support groove; 122. Floating support surface; 123. Limiting shoulder; 124. Axial guide part;

[0038] 130. Reset elastic element;

[0039] 140. Differential anti-sway assembly; 141. Three-lobed pressure ring; 142. Pressure ring unit; 143. Flexible connecting bridge; 144. First inclined push surface; 145. Guide limiting component; 146. Bearing shoulder;

[0040] 150. Radial anti-sway assembly; 151. Radial guide groove; 152. Anti-sway positioning block; 153. Abutment surface; 154. Second inclined push surface; 155. Tension reset component;

[0041] 180. Split-type replaceable support gasket; 181. Anti-rotation key. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0043] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" indicate that the preceding element or object covers the following listed elements or objects and their equivalents, without excluding other elements or objects. "Connected" or "linked" includes direct mechanical connections and indirect mechanical connections formed through intermediate components. Terms such as "upper," "lower," "inner," and "outer" are used only to indicate the relative positional relationships shown in the accompanying drawings.

[0044] Example 1

[0045] like Figures 1 to 9As shown, an anti-sway positioning device for broaching spline holes in an inner ball cage is used to be installed on the worktable of a broaching machine to support and position the inner ball cage to be broached. The positioning device has a fixed seat 110 installed on the worktable 100 and a support platform 120 located above the fixed seat 110. The fixed seat 110 and the support platform 120 are connected by a coaxial hole section to form a central tool passage 111. A support groove 121 is formed on the support platform 120. The support platform 120 is slidably engaged with the fixed seat 110 through an axial guide part 124 and can only move slightly axially. A differential anti-sway component 140 is provided in the support groove 121, and a radial anti-sway component 150 that cooperates with the differential anti-sway component 140 is provided on the support platform 120 to convert the local axial load at each circumferential position into the corresponding radial contact displacement.

[0046] In this embodiment, the worktable 100 can be a fixed worktable of a vertical broaching machine or a transition plate mounted on the broaching machine worktable. The fixed seat 110 is fixed to the worktable 100 by bolts, locating pins, or keyway structures, and is preferably made of 45 steel, 40Cr, or other quenched and tempered steel. The central tool passage 111 is formed by the coaxial hole section on the fixed seat 110 and the support table 120. Its minimum diameter is larger than the outer diameter of the spline hole to be machined and the maximum passing profile of the broaching tool, and is coaxial with the broaching centerline of the broaching machine. The support groove 121 is provided on the upper end face of the support table 120. The inner ball cage is supported only on the support groove 121 or the split replaceable support pad 180 by the lower end annular reference surface. The support table 120 remains coaxial with the central tool passage 111 under the constraint of the axial guide part 124, and does not tilt or swing relative to the fixed seat 110.

[0047] like Figures 2 to 5 As shown, a floating support surface 122 is provided on the fixed base 110. The lower part of the support platform 120 is axially opposite to the floating support surface 122. The axial guide part 124 adopts a structure of guide posts and guide holes arranged circumferentially to limit the radial displacement, circumferential rotation and tilting degree of freedom of the support platform 120. A reset elastic element 130 is provided between the fixed base 110 and the support platform 120. The support groove 121 is an annular groove arranged around the central tool passage 111. The differential anti-sway assembly 140 has a three-lobed pressure ring 141, which is composed of three pressure ring units 142 and a flexible connecting bridge 143 connecting adjacent pressure ring units 142. Each pressure ring unit 142 is movably connected to the support platform 120 through a guide limiting element 145.

[0048] In this embodiment, the axial micro-travel of the support platform 120 relative to the fixed seat 110 is preferably 0.05mm to 0.60mm, and the guiding engagement length of the axial guide part 124 is greater than five times the axial micro-travel to avoid visible tilting of the support platform 120. The reset elastic element 130 can be a disc spring, rectangular spring, wave spring, or rubber elastic ring, and three to six sets are evenly distributed along the circumference. The guide limiting element 145 can be a shoulder screw, whose optical axis section slides into the axial guide hole on the pressure ring unit 142, and a 0.05mm to 0.60mm clearance is reserved between the head and the pressure ring unit 142. The flexible connecting bridge 143 is preferably integrally formed from a thin spring steel bridge, and its axial thickness is less than the axial thickness of the pressure ring unit 142, so that the flexible connecting bridge 143 mainly restricts circumferential misalignment and does not bear the main shearing load.

[0049] like Figures 5 to 8 As shown, each pressure ring unit 142 has a first inclined push surface 144 at its lower part. The radial anti-sway assembly 150 has a radial guide groove 151 formed on the support platform 120. An anti-sway positioning block 152 is slidably disposed in the radial guide groove 151. The side of the anti-sway positioning block 152 near the pressure ring unit 142 has a second inclined push surface 154 that cooperates with the first inclined push surface 144. When the pressure ring unit 142 moves down, the first inclined push surface 144 pushes the second inclined push surface 154, causing the anti-sway positioning block 152 to move along the radial guide groove 151 toward the central through-channel 111. The contact surface 153 of the anti-sway positioning block 152 is preferably adapted to the predetermined outer peripheral positioning band of the inner ball cage, and its effective contact center is higher than the axial support contact surface between the pressure ring unit 142 and the lower end face of the inner ball cage.

[0050] In this embodiment, three pressure ring units 142 are preferably arranged around the central tool passage 111 at 120° intervals, and each pressure ring unit 142 corresponds to an anti-sway positioning block 152. The included angle α between the first inclined push surface 144 and the second inclined push surface 154 and the radial plane is preferably 12° to 25°, and is selected to be greater than the equivalent friction angle of the inclined surface pair to ensure reliable reverse retraction after unloading. Ignoring the elastic deformation of the inclined surface and the assembly gap, the axial displacement Δz of the pressure ring unit 142 and the radial displacement Δr of the anti-sway positioning block 152 satisfy an approximate conversion relationship. The contact surface 153 can be a concave arc surface adapted to the outer peripheral positioning strip of the inner ball cage, or it can be provided with nylon, copper alloy, polyurethane and hard alloy wear-resistant pads to avoid direct compression of the raceway or other functional surfaces of the inner ball cage.

[0051]

[0052] In the formula, Δr represents the radial inward displacement of the anti-sway positioning block 152, Δz represents the axial downward displacement of the pressure ring unit 142, and α represents the angle between the first inclined push surface 144 and the second inclined push surface 154 relative to the radial plane. This relationship is used to determine the radial working stroke of the anti-sway positioning block 152 based on the allowable axial travel.

[0053] like Figure 5 , Figure 6 and Figure 8 As shown, each pressure ring unit 142 has a bearing shoulder 146 at its lower part, and the support platform 120 has a rigid bearing surface opposite to the bearing shoulder 146. During the initial downward stroke, the pressure ring unit 142 drives the anti-sway positioning block 152 to move radially inward through the first inclined push surface 144 and the second inclined push surface 154. When the pressure ring unit 142 moves downward to the set stroke, the bearing shoulder 146 abuts against the rigid bearing surface, so that the subsequent increase in axial tensile load is directly transmitted to the support platform 120 through the bearing shoulder 146, and the radial inward movement of the anti-sway positioning block 152 is no longer increased.

[0054] The aforementioned bearing shoulder 146 forms a two-stage load path: the first stage utilizes a limited axial travel to achieve radial contact, and the second stage involves the rigid bearing surface bearing the main shearing load. The contact position between the bearing shoulder 146 and the rigid bearing surface is determined based on the allowable radial contact amount, preferably making the maximum radial travel of the anti-sway positioning block 152 0.10mm to 1.50mm. The limiting shoulder 123 is used to limit the maximum retraction position of the anti-sway positioning block 152, and an inwardly moving limiting surface is provided in the radial guide groove 151 to prevent the anti-sway positioning block 152 from exceeding the allowable clamping travel.

[0055] like Figures 4 to 8 As shown, a tension reset member 155 is connected between the anti-sway positioning block 152 and the limiting shoulder 123 located radially outward therefrom. The two ends of the tension reset member 155 are connected to the anti-sway positioning block 152 and the limiting shoulder 123, respectively. When the anti-sway positioning block 152 moves inward, the tension reset member 155 is stretched and stores elastic potential energy; after the axial load is released, the tension reset member 155 pulls the anti-sway positioning block 152 outward, and the pressure ring unit 142 returns to its initial position under the reverse action of the inclined pushing surface and the elastic recovery action of the flexible connecting bridge 143.

[0056] In an optional embodiment, the mounting base 110 is provided with a chip removal groove 112 that communicates with the central tool passage 111 and extends to the outer periphery of the mounting base 110, for discharging chips or coolant that fall into the vicinity of the central tool passage 111. The upper surfaces of the three pressure ring units 142 are detachably provided with segmented replaceable support pads 180. Each segmented replaceable support pad 180 is limited and engaged with the corresponding pressure ring unit 142 via an anti-rotation key 181, and a differential gap is reserved between adjacent segmented replaceable support pads 180. Figure 9Only one of the split-type replaceable support pads 180 is shown; the other two are arranged circumferentially.

[0057] In practical use, first fix the fixed seat 110 to the worktable 100 with positioning pins and bolts, aligning the central tool passage 111 with the broaching centerline of the broaching machine. Then, install the corresponding split-type replaceable support shims 180 according to the specifications of the inner ball cage, and confirm that the anti-sway positioning block 152 is in the retracted or lightly abutting position. After broaching begins, the lower end face of the inner ball cage applies an axial load to the three pressure ring units 142. When the force is uniform, the downward movement of the three pressure ring units 142 is similar, and the three anti-sway positioning blocks 152 form a uniform abutment. When the inner ball cage tends to sway to a certain circumferential position, the pressure ring unit 142 corresponding to that position moves downward first and drives the corresponding anti-sway positioning block 152 to increase the radial abutment, while the support table 120 remains coaxial under the constraint of the axial guide part 124. After the anti-sway positioning block 152 reaches the set radial stroke, the bearing shoulder 146 abuts against the rigid bearing surface, and the subsequent broaching load is borne by the support table 120. After the shearing load is released, the reset elastic element 130 pushes the support platform 120 to reset, and the tension reset element 155 pulls the anti-sway positioning block 152 outward.

[0058] It should be noted that the core of this invention does not lie in simply increasing the number of grippers, but in converting the axial load and the circumferential force difference caused by the swaying tendency during the broaching process into radial anti-swaying actions at corresponding positions through the independent pressure ring unit 142, the first inclined push surface 144, the second inclined push surface 154, and the anti-sway positioning block 152. There is a height difference h between the effective contact center of the contact surface 153 and the axial support contact surface, and the radial anti-swaying force Fr applied by the anti-sway positioning block 152 thus forms an anti-swaying torque Mr.

[0059]

[0060] In the formula, Mr represents the anti-sway torque, Fr represents the radial anti-sway force of the anti-sway positioning block 152 acting on the outer periphery of the inner ball cage, and h represents the height difference between the effective contact center of the contact surface 153 and the axial support contact surface.

[0061] Those skilled in the art should understand that the above embodiments are merely examples and are not intended to limit the scope of protection of the present invention to the specific structures described. Without altering the basic principles of differential bearing, inclined plane conversion, radial anti-sway, and load bypass, the technical features in each embodiment can be reasonably combined or equivalently substituted.

[0062] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A positioning device for preventing swaying during broaching of spline holes in an inner ball cage, characterized in that, include: Workbench (100), mounting base (110) on the workbench (100) and support platform (120) above the mounting base (110). The fixed base (110) is connected to the coaxial hole section on the support platform (120) to form a central tool passage (111) for the broaching tool to pass through, and a support groove (121) for supporting the lower end face of the inner ball cage is formed on the support platform (120). The support platform (120) slides with the fixed seat (110) through the axial guide part (124), so that the support platform (120) can only generate a small displacement along the axial direction of the central tool passage (111); The support groove (121) is provided with a differential anti-sway assembly (140). The differential anti-sway assembly (140) has multiple pressure ring units (142) arranged circumferentially and capable of bearing the local axial load of the inner ball cage respectively. Each pressure ring unit (142) can move slightly downward axially relative to the support platform (120). The support platform (120) is provided with radial anti-sway components (150) corresponding to each of the pressure ring units (142). Each radial anti-sway component (150) is used to convert the axial displacement of the corresponding pressure ring unit (142) into a radial contact displacement toward the central through-channel (111). When the inner ball cage has a tendency to sway, the circumferential position with a larger axial load will preferentially increase the radial contact amount of the corresponding position.

2. The anti-wobbling positioning device for broaching spline holes in an inner ball cage according to claim 1, characterized in that: The axial guide portion (124) includes guide posts spaced apart along the circumference and guide holes that slide with the guide posts. A floating support surface (122) is provided on the fixed seat (110). A reset elastic element (130) is provided between the fixed seat (110) and the support platform (120). The reset elastic element (130) is used to push the support platform (120) to reset along the axial guide portion (124) after the axial shear load is released.

3. The anti-wobbling positioning device for broaching spline holes in an inner ball cage according to claim 2, characterized in that: The support groove (121) is an annular groove arranged around the central through channel (111). The differential anti-sway assembly (140) has a three-lobed pressure ring (141) disposed in the support groove (121). The three-lobed pressure ring (141) is composed of three pressure ring units (142) distributed circumferentially and a flexible connecting bridge (143) connecting adjacent pressure ring units (142).

4. The anti-wobbling positioning device for broaching spline holes in an inner ball cage according to claim 3, characterized in that: Each of the pressure ring units (142) is movably connected to the support platform (120) through a guide limiting member (145). The guide limiting member (145) passes through the corresponding pressure ring unit (142) axially and is connected to the support platform (120). An axial movement gap is reserved between the head of the guide limiting member (145) and the pressure ring unit (142) to limit the radial movement and circumferential misalignment of the pressure ring unit (142).

5. The anti-sway positioning device for broaching spline holes in an inner ball cage according to claim 4, characterized in that: Each of the pressure ring units (142) has a first inclined push surface (144) at its lower part. The radial anti-sway assembly (150) has a radial guide groove (151) opened on the support platform (120). An anti-sway positioning block (152) is slidably arranged in the radial guide groove (151). A second inclined push surface (154) that cooperates with the first inclined push surface (144) is provided on the anti-sway positioning block (152). When the pressure ring unit (142) moves down, the anti-sway positioning block (152) is pushed radially inward by the first inclined push surface (144) and the second inclined push surface (154).

6. The anti-wobbling positioning device for broaching spline holes in an inner ball cage according to claim 5, characterized in that: The anti-sway positioning block (152) has a contact surface (153) on one side facing the central through channel (111). The effective contact center of the contact surface (153) is higher than the axial support contact surface between the pressure ring unit (142) and the lower end face of the inner ball cage to form a height difference h.

7. The anti-wobbling positioning device for broaching spline holes in an inner ball cage according to claim 5, characterized in that: The support platform (120) is provided with a limiting shoulder (123). A tension reset member (155) is connected between the anti-sway positioning block (152) and the limiting shoulder (123) located on its radial outer side. When the anti-sway positioning block (152) moves radially inward, it stretches the tension reset member (155). After the axial load is released, the tension reset member (155) pulls the anti-sway positioning block (152) outward.

8. The anti-wobbling positioning device for broaching spline holes in an inner ball cage according to claim 5, characterized in that: Each of the pressure ring units (142) is provided with a bearing shoulder (146) at its lower part, and the support platform (120) is provided with a rigid bearing surface opposite to the bearing shoulder (146); the pressure ring unit (142) drives the anti-sway positioning block (152) to move radially inward within the initial downward stroke, and after reaching the set stroke, the bearing shoulder (146) abuts against the rigid bearing surface, so that the subsequent increased axial load is transmitted to the support platform (120) through the bearing shoulder (146).

9. The anti-wobbling positioning device for broaching spline holes in an inner ball cage according to claim 3, characterized in that: The fixed base (110) is provided with a chip removal groove (112) that communicates with the central tool passage (111). The upper surfaces of the three pressure ring units (142) are respectively provided with split-type replaceable support pads (180). Each split-type replaceable support pad (180) is limited to the corresponding pressure ring unit (142) through an anti-rotation key (181). A differential gap is reserved between adjacent split-type replaceable support pads (180).

10. The anti-wobbling positioning device for broaching spline holes of an inner ball cage according to claim 3, characterized in that: The three-lobed pressure ring (141) is integrally formed from spring steel. The axial thickness of the flexible connecting bridge (143) is less than the axial thickness of the pressure ring unit (142). A circumferential separation gap is formed between adjacent pressure ring units (142) to allow each pressure ring unit (142) to move axially independently within a limited stroke.

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