A long displacement cross-ballway universal joint

Abstract

The invention discloses a long displacement cross ball track universal joint, which relates to the technical field of vehicle transmission devices. It comprises: an inner ball cage with an outer ball track inside, one end of the inner ball cage is an open end, and the other end is a mounting end; a star-shaped sleeve with an inner ball track, the star-shaped sleeve is arranged in the cavity of the inner ball cage; a retaining frame for receiving steel balls; the retaining frame is arranged between the outer ball track and the inner ball track; steel balls for transmitting torque, the steel balls are guided in the track formed between the outer ball track and the inner ball track; the cross-sectional shape of the outer curved surface of the star-shaped sleeve is composed of four arcs, or two straight lines with inclined angles, or one straight line and two arcs. When the universal joint slides, it is limited and self-locked between the retaining frame and the star-shaped sleeve; the offset angle ratio of the axis of the star-shaped sleeve and the axis of the retaining frame relative to the axis of the inner ball cage is 2:1; the displacement ratio of the center plane of the star-shaped sleeve and the center plane of the retaining frame relative to the center point of the inner ball cage is 2:1, thereby achieving a displacement stroke of more than 50mm.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle transmission devices, and in particular to a long-displacement cross-spherical universal joint. Background Art

[0002] The existing different constant velocity universal joints for automobile sliding ends mainly include eight-ball DO joints, tripod universal joints, eight-ball VL joints, etc. The disadvantages of the eight-ball DO joint are that the effective length of the ballway is long, the cost of the milling cutter is high, the precision requirement is high, and the processing in stages is required; the disadvantages of the tripod universal joint are that the roller bearing is expensive, and under the swing angle condition, the three ballways are unevenly stressed, which can easily cause vehicle shaking due to the influence of manufacturing precision, and poor NVH performance.

[0003] The invention patent with the patent number CN 110945258 B discloses a ball type constant velocity sliding universal joint, which at least comprises: an outer part of the universal joint with a rotation axis and an external ball track; an inner part of the universal joint with an internal ball track; a large number of balls for transmitting torque, which are respectively guided in the external ball track and the internal ball track associated with each other; a ball cage, which is provided with a large number of ball cage windows, which respectively accommodate one or more balls among the balls; the inner part of the universal joint can slide a sliding stroke along the rotation axis relative to the outer part of the universal joint; the maximum deflection angle of the inner part of the universal joint relative to the outer part of the universal joint is preset by the contact between the external contact surface of the ball cage and the first contact surface of the outer part of the universal joint and / or by the contact between the internal contact surface of the ball cage and the second contact surface of the inner part of the universal joint; the ball cage has a ball cage center axis, and the internal contact surface is conically shaped; the internal contact surface has an opening angle of more than 0° relative to the ball cage center axis.

[0004] The ball-type constant velocity sliding universal joint provided by the above prior art has further improved fatigue resistance. However, it is difficult for the existing universal joint to achieve a displacement of ≥50 mm, which greatly limits the application scope of the universal joint. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a long-displacement cross-spherical universal joint having the advantages of low cost, high precision, high NVH performance, and a sliding end displacement ≥ 50 mm, which can be used to transmit power in a front-wheel drive shaft.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a long displacement cross-ballway universal joint, the universal joint comprising:

[0007] An inner ball cage, which is an outer component of a universal joint with an outer ball track inside, one end of the inner ball cage is an open end, and the other end is a mounting end;

[0008] A star-shaped sleeve, which is an inner component of a universal joint with an inner ball track, and is arranged in the cavity of the inner ball cage;

[0009] A retainer, the retainer is used to receive the steel balls; the retainer is arranged between the outer ball track and the inner ball track;

[0010] Steel balls, the steel balls are used to transmit torque, the steel balls are located at the intersection of the outer ball track and the inner ball track, and are guided in a track formed between the outer ball track and the inner ball track;

[0011] The outer side of the star-shaped sleeve close to the retainer is a star-shaped sleeve outer curved surface, and the cross-sectional shape of the star-shaped sleeve outer curved surface is composed of four arc segments, or two straight lines with inclined angles, or one straight line and two arc segments;

[0012] At the center of the joint, the center plane of the inner ball cage, the center plane of the star sleeve and the center plane of the retaining frame coincide with each other; when the universal joint slides, the star sleeve is prevented from falling out by limiting the self-locking between the inner surface of the retaining frame and the star sleeve; the offset angle ratio of the star sleeve axis and the retaining frame axis relative to the inner ball cage axis is 2:1; the displacement ratio of the star sleeve center plane and the retaining frame center plane relative to the center point of the inner ball cage is 2:1, thereby achieving a displacement stroke of more than 50mm.

[0013] Furthermore, the cross-sectional shape of the outer curved surface of the star sleeve is composed of four arcs, the radii of which are R2, R1, R4 and R5 respectively, wherein R1=R4, R2=R5, and R2>R1; the inner surface of the retainer is an inner eccentric arc R3.

[0014] Furthermore, in the 0-degree slip condition, the inner eccentric arc R3 of the retaining frame and the outer arcs R1 and R4 of the star sleeve are limited and self-locked to prevent the star sleeve from falling out and the steel ball from losing its restraint.

[0015] Furthermore, in the working condition of swing angle slip, the inner eccentric arc R3 of the retaining frame and the outer arcs R2 and R5 of the star sleeve are limited and self-locked to prevent the star sleeve from falling out and the steel ball from losing restraint.

[0016] Furthermore, the central angles of the arcs with radii R1 and R4 are both δ / 2, and the range of δ is the maximum swing angle of the section.

[0017] Furthermore, the inner ball cage is provided with 2N outer ball channels, and the star-shaped sleeve is provided with 2N inner ball channels; wherein N≥3.

[0018] Furthermore, the angle between the outer ball track and the inner ball cage axis is θ1, and the angle between the inner ball track and the star sleeve axis is θ2; θ1 and θ2 are in opposite directions; after the product is assembled, the outer ball track and the inner ball track form a cross X-shaped track pair.

[0019] Furthermore, the range value of θ1 is 0°<θ1≤10°; the range value of θ2 is 0°<θ2≤10°.

[0020] Furthermore, the center point of the eccentric arc of the inner circle of the retainer is longitudinally offset downward relative to the central axis of the segment profile, and the offset distance = (R3*2-φd) / 2, wherein d is the diameter of the circle where the eccentric arc of the inner circle of the retainer is located.

[0021] Furthermore, the cross-sectional shape of the inner surface of the retainer is a middle arc connected to two straight lines with inclined angles, and the sum of the inclination angle of the straight line and the included angle of the ball track is equal to the maximum swing angle of the section.

[0022] The beneficial effects of the present invention are as follows: compared with the eight-ballway DO joint type, the long-displacement cross-ballway universal joint provided by the present invention has an effective ballway length of only 3 / 5 of that of the eight-ballway DO joint, the cost of the milling cutter is reduced, no grading is required, and the production efficiency is greatly improved; compared with the three-ball pin universal joint, the long-displacement cross-ballway universal joint provided by the present invention compensates for the lead error, spacing error, and indexing error formed when the inclination directions of the ballway grooves are the same through the design of ballways in opposite directions, so that the radial and circumferential clearances of the steel ball assembly in the ballway grooves become smaller, and the NVH performance is more superior; compared with the existing eight-ballway VL joint, the large-stroke cross-ballway universal joint PCJL joint type with eccentricity R provided by the present invention has the high precision of ordinary VL joints, and can achieve a long displacement of ≥50mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of the universal joint provided by the present invention.

[0024] Figure 2 This is a schematic cross-sectional structure diagram of the universal joint provided by the present invention.

[0025] Figure 3 This is a schematic diagram of the three-dimensional structure of the universal joint provided by the present invention.

[0026] Figure 4 and Figure 5 This is a schematic diagram of the structure of the universal joint provided by the present invention in different displacement states.

[0027] Figure 6 This is a simulation diagram of the steel ball position points in the universal joint provided by the present invention when the inner and outer ball tracks are in the zero displacement state.

[0028] Figure 7 This is a simulation diagram of the steel ball position points when the inner and outer ball tracks in the universal joint provided by the present invention are displaced outward.

[0029] Figure 8This is a simulation diagram of the steel ball position points when the inner and outer ball tracks of the universal joint provided by the present invention are displaced inward.

[0030] Among them, 1-inner ball cage; 2-star sleeve; 3-cage; 4-outer curved surface of star sleeve; 5-steel ball; 6-outer ball track; 7-inner ball track; 8-section center axis; 9-inner surface of cage; 10-installation end; 11-open end; L1-inner ball cage axis; L2-star sleeve axis. DETAILED DESCRIPTION

[0031] The present invention is further described below by specific examples, but these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Example

[0032] like Figures 1 to 8 As shown, a long displacement cross ball track universal joint, the universal joint comprises: an inner ball cage 1, the inner ball cage 1 is an outer component of the universal joint with an outer ball track 6 inside, one end of the inner ball cage 1 is an open end 11, and the other end is a mounting end 10; a star sleeve 2, the star sleeve 2 is an inner component of the universal joint with an inner ball track 7, the star sleeve 2 is arranged in the cavity of the inner ball cage 1; a retainer 3, the retainer 3 is used to receive a steel ball 5; the retainer 3 is arranged on the outer ball track 6 and the inner ball track 7; steel ball 5, the steel ball 5 is used to transmit torque, the steel ball 5 is located at the intersection of the outer ball track trajectory and the inner ball track trajectory, and the steel ball 5 is guided in the track formed between the outer ball track 6 and the inner ball track 7; the outer side of the star sleeve 2 close to the retainer 3 is the star sleeve outer curved surface 4, the cross-sectional shape of the star sleeve outer curved surface 4 is composed of four arcs, or two straight lines with inclined angles, or one straight line and two arcs. At the center of the joint, the center plane of the inner ball cage, the center plane of the star sleeve and the center plane of the retainer coincide with each other; when the universal joint slides, the inner surface 9 of the retainer and the star sleeve 2 are limited and self-locked to prevent the star sleeve 2 from falling out; the offset angle ratio of the axis L2 of the star sleeve and the axis of the retainer relative to the axis L1 of the inner ball cage is 2:1; the displacement ratio of the center plane of the star sleeve and the center plane of the retainer relative to the center point of the inner ball cage is 2:1, thereby achieving a displacement stroke of more than 50mm.

[0033] As one of the embodiments, the cross-sectional shape of the outer curved surface 4 of the star sleeve is composed of four arcs, and the radii of the four arcs are R2, R1, R4 and R5, wherein R1=R4, R2=R5, and R2>R1. The inner surface 9 of the retainer is an inner eccentric arc R3. The four arcs are used to limit the stroke of the star sleeve 2 under the conditions of no swing angle and swing angle, to prevent the star sleeve 2 from falling out, the steel ball 5 from losing its restraint, and causing the whole vehicle to fail during operation. The specific principle is: under the 0-degree slip condition, the inner circle eccentricity R3 of the cage is limited by R1 and R4; under the swing angle slip condition, the inner circle eccentricity R3 of the cage is limited by R2 and R5. In order to meet the customer's operating process conditions, we designed the inner circle shape to be symmetrical relative to the center plane, so that the core shaft and the inner ball cage mouth do not interfere with each other. Compared with the tripod joint type and DO joint type, the PCJL has a larger sliding range and can meet the different jump point requirements of customers.

[0034] Furthermore, the central angles of the arcs with radii R1 and R4 are both δ / 2, and the range of δ is the maximum swing angle of the section.

[0035] As one of the embodiments, the cross-sectional shape of the outer curved surface 4 of the star-shaped sleeve is composed of two straight lines with inclined angles, the sum of the straight line inclination + the ballway angle ≥ the maximum swing angle of the section, and the inclination angles of the two straight lines are in opposite directions.

[0036] As one of the embodiments, the cross-sectional shape of the outer curved surface 4 of the star sleeve is composed of a straight line and two arcs, wherein the straight line is in the middle and the two arcs are connected to the two ends of the straight line respectively. The length of the straight line is ≥ the distance from the outer diameter of the star sleeve to the angle of δ / 2 on one side of the section center, the straight line height of the star sleeve is 2.5~3.5mm less than the inner diameter of the cage, and the arcs at both ends are fitted with the inner surface of the cage for limiting when the swing angle is met.

[0037] The inner ball cage 1 is provided with 2N outer ball channels, and the star-shaped sleeve 2 is provided with 2N inner ball channels; wherein N≥3; in this embodiment, N is preferably 4.

[0038] The angle between the outer ball track 6 and the inner ball cage axis L1 is θ1, and the angle between the inner ball track 7 and the star sleeve axis L2 is θ2; θ1 and θ2 are in opposite directions; after the product is assembled, the outer ball track 6 and the inner ball track 7 present a cross X-shaped track pair. Furthermore, the range value of θ1 is 0°<θ1≤10°; the range value of θ2 is 0°<θ2≤10°; θ1=θ2. In this embodiment, θ1 and θ2 are preferably 9 degrees or 7 degrees. When the displacement is long, the change in the angle value will affect the distance between the adjacent ball tracks. When the angle is greater than 10 degrees, if a displacement of more than 50 mm is to be satisfied, the adjacent ball tracks will intersect and cannot be used.

[0039] In one embodiment, the center point of the eccentric arc of the inner circle of the retainer is offset longitudinally downward relative to the central axis 8 of the segment, and the offset distance = (R3*2-φd) / 2, where d is the diameter of the circle where the eccentric arc of the inner circle of the retainer is located.

[0040] In one embodiment, the cross-sectional shape of the inner surface 9 of the cage is a middle arc connected to two straight lines with an inclined angle, and the sum of the inclination angle of the straight line and the included angle of the ballway is equal to the maximum swing angle of the section. The center of the middle arc is concentric with the center of the cage window, and the inclination angle of the straight line satisfies half of the inclination angle of the star sleeve straight line.

[0041] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A long displacement cross-spherical universal joint, characterized in that: The universal joint comprises: An inner ball cage, which is an outer component of a universal joint with an outer ball track inside, one end of the inner ball cage is an open end, and the other end is a mounting end; A star-shaped sleeve, which is an inner component of a universal joint with an inner ball track, and is arranged in the cavity of the inner ball cage; A retainer, the retainer is used to receive the steel balls; the retainer is arranged between the outer ball track and the inner ball track; Steel balls, the steel balls are used to transmit torque, the steel balls are located at the intersection of the outer ball track and the inner ball track, and are guided in a track formed between the outer ball track and the inner ball track; The outer side of the star-shaped sleeve close to the retainer is a star-shaped sleeve outer curved surface, and the cross-sectional shape of the star-shaped sleeve outer curved surface is composed of four arcs; when the cross-sectional shape of the star-shaped sleeve outer curved surface is composed of four arcs, the radii of the four arcs are R2, R1, R4 and R5, wherein R1=R4, R2=R5, and R2>R1; the side of the retainer close to the star-shaped sleeve is an inner eccentric arc R3; the central angles of the arcs with radii R1 and R4 are both δ / 2, and the range of δ is the maximum swing angle of the section; The angle between the outer ball track and the axis of the inner ball cage is θ1, and the angle between the inner ball track and the axis of the star sleeve is θ2; θ1 and θ2 are in opposite directions; after the product is assembled, the outer ball track and the inner ball track present a cross X-shaped track pair; the range value of θ1 is 0°<θ1≤10°; the range value of θ2 is 0°<θ2≤10°; At the center of the joint, the center plane of the inner ball cage, the center plane of the star sleeve and the center plane of the cage coincide with each other; the outer curved surface of the star sleeve is designed symmetrically with respect to the center plane of the star sleeve; when the universal joint slides, the cage and the star sleeve are self-locked to prevent the star sleeve from falling out; the offset angle ratio of the star sleeve axis and the cage axis relative to the inner ball cage axis is 2:1; the displacement ratio of the center plane of the star sleeve and the center plane of the cage relative to the center point of the inner ball cage is 2:1, thereby achieving a displacement stroke of more than 50mm; In the 0-degree slip condition, the inner eccentric arc R3 of the retainer and the outer arcs R1 and R4 of the star sleeve are limited and self-locked to prevent the star sleeve from falling out and the steel ball from losing its restraint; In the working condition of swing angle slip, the inner eccentric arc R3 of the retainer and the outer arcs R2 and R5 of the star sleeve are limited and self-locked to prevent the star sleeve from falling out and the steel ball from losing restraint.

2. A long displacement cross-spherical universal joint as claimed in claim 1, characterized in that: The inner ball cage is provided with 2N outer ball channels, and the star-shaped sleeve is provided with 2N inner ball channels; wherein N≥3.

3. A long displacement cross-spherical universal joint as claimed in claim 1, characterized in that: The center point of the eccentric arc of the inner circle of the retainer is offset longitudinally downward relative to the central axis of the segment, and the offset distance = (R3*2-φd) / 2, where d is the diameter of the circle where the eccentric arc of the inner circle of the retainer is located.

4. A long displacement cross-spherical universal joint as claimed in claim 1, characterized in that: The cross-sectional shape of the retainer on one side close to the star-shaped sleeve is a middle arc connecting two sides of straight lines with inclined angles, and the sum of the inclination angle of the straight line and the included angle of the ball track is equal to the maximum swing angle of the section.

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