CN117948344A - Bearing assembly and recirculating ball steering gear - Google Patents

Abstract

Disclosed is a bearing assembly for a recirculating ball steering gear in a steering system, the bearing assembly comprising: a screw having a first end and an opposite second end; and a thrust bearing disposed on the first end of the screw and comprising a bearing race and a bearing ball; the bearing race comprises a left half race and a right half race, the left half race and the right half race are respectively provided with an outer raceway, and the screw is provided with an inner raceway at or near the first end, which corresponds to the outer raceway of the left half race and the outer raceway of the right half race respectively; when the thrust bearing is in an assembled state on the screw, the bearing steel balls are in contact with the outer race of the left half-race, the outer race of the right half-race, and the inner race of the screw, and the left and right half-races are in contact with each other in a clearance-free manner in the longitudinal direction of the recirculating ball steering gear, so that the steering clearance of the steering system is minimized with the use of a unitized assembly. An endless ball steering gear comprising the above bearing assembly is also disclosed.

Description

Bearing assembly and recirculating ball steering gear

Technical Field

The present disclosure relates generally to a bearing assembly. More particularly, the present disclosure relates to a bearing assembly for a recirculating ball steering gear in a steering system. The present disclosure also relates to an recirculating ball steering gear including the bearing assembly.

Background

In the field of vehicles, a steering gear is an important component of a steering system, and is mainly used for increasing the force transmitted from a steering wheel to a steering transmission mechanism and changing the transmission direction of the force. Common steering gears include rack and pinion steering gears, worm crank pin steering gears, recirculating ball steering gears, and the like.

In recirculating ball steering, a screw is used to receive rotation from the steering shaft. The screw is fixed into the housing of the steering gear by means of a thrust bearing and a valve body. There are mainly two types of screw thrust bearings. A rolling needle type bearing is suitable for a steering gear with a through screw, and the steering gear does not limit the radial direction of the screw. The other type is a thrust ball bearing which is suitable for a steering gear with a non-through screw rod, and the thrust ball bearing axially positions and bears the axial force of the screw rod of the steering gear when in use, and also radially positions and bears the radial force of the screw rod of the steering gear. In recirculating ball steering, the force exerted by the screw can be up to several kilonewtons.

Chinese patent application CN106481655A discloses a thrust ball thrust bearing for a recirculating ball steering gear. In practical application, the steering intermediate shaft has a larger deflection angle with the input shaft of the steering gear, so that a larger radial force is brought to the input shaft of the steering gear in the steering wheel rotating process. The large radial force makes the three sealing rings in the valve body very susceptible to wear, thus causing internal leakage and heavy turning. In addition, the large radial force may also cause increased wear at the seal between the input shaft of the steering gear and the oil seal, thereby creating leakage. Secondly, the thrust bearing in this patent application cannot well withstand the large axial forces brought by the screw due to the gap between the left and right half races. Again, as the vehicle field increases in steering accuracy and sensitivity requirements, users desire steering systems with smaller steering clearances to reduce the process time required for the user to turn the steering wheel to move the steering arms in response to the turn during a steering operation. The gap existing between the left and right half races of this patent application makes it difficult for the user to precisely adjust and achieve the desired fit gap between the bearing race and the bearing ball, and thus to precisely adjust and achieve a small steering gap. This is because, in this patent application, the fit gap between the bearing race and the bearing ball is determined by the fit between the three parameters of the outer raceway diameter of the left and right half-races, the gap between the left and right half-races, and the diameter of the bearing ball itself. In actual assembly, it is often difficult to precisely control these three parameters simultaneously, since the component dimensions have tolerances and the gap between the left and right race halves can vary as the fastening nut is tightened, resulting in difficulty in achieving and maintaining the desired fit gap. The fit gap between the bearing race and the bearing ball may determine the size of the steering gap, as is well known in the art.

There is also no disclosure in other prior art of a bearing assembly capable of solving the above-mentioned technical problems under the circumstance of bearing a high force in a steering gear.

Disclosure of Invention

It is an object of the present disclosure to provide a bearing assembly and an endless ball steering comprising the same that overcome at least one of the drawbacks of the prior art.

Disclosed is a bearing assembly for a recirculating ball steering gear in a steering system, the bearing assembly comprising: a screw having a first end and an opposite second end, and a thrust bearing disposed on the first end of the screw and comprising a bearing race and a bearing ball; the bearing race comprises a left half race and a right half race, wherein the left half race and the right half race are respectively provided with an outer raceway, and the screw is provided with an inner raceway at or near the first end, which corresponds to the outer raceway of the left half race and the outer raceway of the right half race respectively; wherein when the thrust bearing is in an assembled state on the screw, the bearing steel balls are in contact with the outer race of the left half-race, the outer race of the right half-race, and the inner race of the screw, and the left half-race and the right half-race are in contact with each other in a clearance-free manner in the longitudinal direction of the recirculating ball steering gear, thereby minimizing a steering clearance of the steering system with a unitized assembly.

In one embodiment, the recirculating ball steering gear further comprises a valve body sealing an interior space of the recirculating ball steering gear, and an adjusting nut screwed into the valve body, wherein the left and right half races abut the adjusting nut and the valve body in the longitudinal direction without play.

In one embodiment, the bearing steel ball is in contact with the outer raceway of the left half seat ring and the outer raceway of the right half seat ring at a first contact point and a second contact point respectively, and a connecting line of the first contact point and the second contact point with the ball center of the bearing steel ball forms an included angle relative to a vertical plane perpendicular to the longitudinal direction. In another embodiment, the included angle is about 45 °, greater than 45 °, or less than 45 °.

In one embodiment, the bearing steel ball is in contact with the inner raceway of the screw at a third contact point and a fourth contact point, respectively, and the connecting line of the third contact point and the fourth contact point with the ball center of the bearing steel ball forms an included angle with respect to a vertical plane perpendicular to the longitudinal direction. In yet another embodiment, the included angle is about 45 °, greater than 45 °, or less than 45 °.

In one embodiment, the bearing races are configured to be divided into groups in the group assembly method by the diameter dimension of their outer raceways, the difference between the maximum and minimum values of the diameter dimension of the outer raceways of each group bearing race being in the range of 2 to 8 microns.

In one embodiment, the outer raceways of the left and right half-races together form an outer raceway chip flute at the location where they are joined to each other.

In one embodiment, an inner race chip flute is formed on the inner race of the screw in correspondence with the outer race chip flute.

In one embodiment, the thrust bearing further includes a cage configured such that no contact between the bearing balls occurs.

In one embodiment, the left and right half races abut the valve body in a radial direction of the thrust bearing.

Also disclosed is a recirculating ball steering gear comprising a bearing assembly as described above for a recirculating ball steering gear in a steering system.

In one embodiment, the recirculating ball steering gear further comprises a valve body configured to seal an interior space of the recirculating ball steering gear.

In one embodiment, the valve body includes first and second coaxially aligned central bores, and the first and second central bores are connected by a step.

In one embodiment, the first central bore is proximate the interior space and the second central bore is proximate an exterior of the recirculating ball diverter, and the first central bore has a diameter that is less than a diameter of the second central bore.

In one embodiment, the valve body is supported on the first end of the screw through the first central bore.

In one embodiment, a thrust bearing of the bearing assembly is received in the second central bore of the valve body and abuts the step in a longitudinal direction with no gap.

In one embodiment, the recirculating ball steering gear further comprises an adjustment nut configured to be threaded into the second central bore and abut the left half-race of the thrust bearing without play.

Additional features and advantages of the subject technology of the present disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the subject technology of the present disclosure. The advantages of the subject technology of the present disclosure will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the subject technology of the present disclosure as claimed.

Drawings

The present disclosure will be more readily understood from the following detailed description taken in conjunction with the accompanying drawings, wherein like reference numerals designate like elements. The drawings are schematic and are non-limiting. Elements in the figures are not necessarily shown to scale, e.g., elements may be exaggerated for purposes of illustration or may be drawn on scale to keep the figures clear and easy to understand.

In the drawings:

Fig. 1 shows a schematic view of a steering system of a vehicle.

Fig. 2 shows a perspective view of the recirculating ball steering gear of the steering system shown in fig. 1 and an attached steering arm.

FIG. 3 illustrates a cross-sectional view of the recirculating ball steering gear shown in FIG. 2 including a bearing assembly in accordance with an embodiment of the present disclosure.

Fig. 4 shows an enlarged view of the circled portion a in fig. 3.

Fig. 5 illustrates a schematic diagram of the engagement between steel balls and bearing races in a bearing assembly according to an embodiment of the present disclosure.

Detailed Description

The present disclosure will be described below with reference to the accompanying drawings, which illustrate several embodiments of the present disclosure. It should be understood, however, that the present disclosure may be presented in many different ways and is not limited to the embodiments described below; indeed, the embodiments described below are intended to more fully convey the disclosure to those skilled in the art and to fully convey the scope of the disclosure. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide yet additional embodiments.

It should be understood that throughout the drawings, like reference numerals refer to like elements. In the drawings, the size of certain features may be modified for clarity.

It should be understood that the terminology used in the description is for the purpose of describing particular embodiments only, and is not intended to be limiting of the disclosure. All terms (including technical and scientific terms) used in the specification have the meanings commonly understood by one of ordinary skill in the art unless otherwise defined. Well-known functions or constructions may not be described in detail for brevity and/or clarity.

As used in this specification, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. The use of the terms "comprising," "including," and "containing" in the specification mean that the recited features are present, but that one or more other features are not excluded. The use of the phrase "and/or" in the specification includes any and all combinations of one or more of the associated listed items. The words "between X and Y" and "between about X and Y" used in this specification should be interpreted to include X and Y. The phrase "between about X and Y" as used herein means "between about X and about Y", and the phrase "from about X to Y" as used herein means "from about X to about Y".

In the description, an element is referred to as being "on," "attached" to, "connected" to, "coupled" to, "contacting" or the like another element, and the element may be directly on, attached to, connected to, coupled to or contacting the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly on," "directly attached to," directly connected to, "directly coupled to," or "directly contacting" another element, there are no intervening elements present. In the specification, one feature is arranged "adjacent" to another feature, which may mean that one feature has a portion overlapping with the adjacent feature or a portion located above or below the adjacent feature.

In the specification, spatial relationship words such as "upper", "lower", "left", "right", "front", "rear", "high", "low", and the like may describe the relationship of one feature to another feature in the drawings. It will be understood that the spatial relationship words comprise, in addition to the orientations shown in the figures, different orientations of the device in use or operation. For example, when the device in the figures is inverted, features that were originally described as "below" other features may be described as "above" the other features. The device may also be otherwise oriented (rotated 90 degrees or at other orientations) and the relative spatial relationship will be explained accordingly.

Referring to fig. 1, fig. 1 shows a schematic view of a steering system of a vehicle. The steering wheel 1 can be rotated by receiving a steering operation from the driver. The steering column set 2 connected to the steering wheel 1 receives the rotation and transmits the rotation to the steering gear 100 via a universal joint. The steering gear 100 converts the rotational motion from the steering column set 2 into a rocking motion, and outputs the rocking motion to the steering rocker 4. The steering rocker arm 4 converts swinging motion into reciprocating motion through a straight pull rod, and drives the wheels 3 on the same side through the steering knuckle arm to steer the wheels on the side by taking a master pin on the side as a rotation center; simultaneously, the steering tie rod arm on the side is pulled to drive the steering tie rod to reciprocate, the motion is transmitted to the steering tie rod arm on the opposite side, and then the wheels on the opposite side are pulled to rotate by taking the kingpin as the center, so that the steering of the steering knuckle is realized, the wheels 3 of the vehicle are rotated, and the steering of the vehicle is realized.

Referring now to fig. 2 and 3, fig. 2 and 3 show perspective and cross-sectional views, respectively, of an recirculating ball steering gear 100 including a bearing assembly in accordance with the present disclosure. The diverter 100 may include a housing 20, a screw 30 disposed within the housing 20, a piston 50, and a sector gear 60. Hereinafter, a direction along the central axis of the steering gear 100 will be referred to as a longitudinal direction, and a direction perpendicular to the longitudinal direction and perpendicular to the paper surface of fig. 3 will be referred to as a lateral direction.

The housing 20 may be used to house and support the various components of the steering gear 100. The housing 20 may be in the shape of a generally hollow cylinder. The housing 20 has an open first end 21 and a closed second end 22 opposite the first end in the longitudinal direction. The housing 20 also has an inner space 23 extending in the longitudinal direction for accommodating the screw 30 and the piston 50. The housing 20 may also have a projection 25 extending radially outwardly from the sidewall of the barrel. The protruding portion 25 is hollow and defines a receiving space 26 for receiving the sector gear 60. The accommodation space 26 and the inner space 23 communicate with each other.

The screw 30 converts the rotational movement from the steering wheel 1 into a reciprocating movement of the piston 50 by its cooperation with the piston 50. The screw 30 has a first end 31 and a second end 32 opposite the first end 31 along a longitudinal axis. The screw 30 includes a screw recess 33 extending in a helical fashion on its screw outer wall 35 for use with a piston recess 53 (described in more detail below). The screw 30 has a screw cavity open at a first end 31 and extending in a longitudinal direction for receiving an input shaft of the steering gear 100, thereby receiving rotational movement from the steering wheel 1. The screw 30 cooperates with the thrust bearing 10, the valve body 40 and the adjustment nut 70 near the first end 31, as will be described in detail below.

The piston 50 is disposed in the inner space 23 of the housing 20 and is reciprocally movable in the longitudinal direction by the drive of the screw 30, thereby driving the sector gear 60 to perform a rocking motion about the lateral direction. The piston 50 may be in the shape of a generally hollow cylinder. The piston 50 has an open first end 55 and a closed second end 56 opposite the first end 55 in the longitudinal direction. The piston 50 includes an inner cavity 51 extending in a longitudinal direction between a first end 55 and a second end 56 of the piston 50. The interior cavity 51 is defined by an interior wall 52.

The interior cavity 51 receives the screw 30 from the first end 55. The inner wall 52 is provided with a piston recess 53 in the form of a spiral to cooperate with the screw recess 33 of the screw 30. The screw 30 is threaded into the interior cavity 51 of the piston 50 in a longitudinal direction from the first end 55 of the piston 50, while a plurality of steerer balls 80 of a recirculating ball type deflector are placed in the ball channel formed by the screw recess 33 together with the piston recess 53, thereby effecting engagement of the screw 30 with the piston 50.

The piston 50 is provided at its outer side wall facing the projection 25 of the housing 20 with a first set of teeth 54 for engagement with a second set of teeth 64 of the sector gear 60.

The sector gear 60 serves to convert the reciprocating movement of the piston 50 into a rocking movement. The sector gear 60 is mounted in the receiving space 26 of the housing 20 and is engaged with the piston 50 by engagement of the second set of teeth 64 of the sector gear with the first set of teeth 54 of the piston 50 as described above. The reciprocating movement of the piston 50 drives the sector gear 60 in a rocking motion about the lateral direction. The sector gear 60 is coupled to the pitman arm 4 to drive the pitman arm 4 in a rocking motion.

The diverter 100 may also include a valve body 40. A valve body 40 is mounted to the housing 20 at the first end 21 for sealing the interior space 23 of the housing 20. The valve body 40 has a continuous hole penetrating in the longitudinal direction. The connection holes include a first center hole 41 near the inner space 23 of the housing 20 and a second center hole 42 near the outside of the deflector 100, the first center hole 41 and the second center hole 42 being coaxially aligned and communicating with each other. The first central hole 41 has a smaller diameter than the second central hole 42, and the two central holes are connected by a step 43. The first central bore 42 of the valve body 40 is for engaging the first end 31 of the screw 30. One or more spaced-apart sealing rings 81 (one of which is identified in fig. 4) may be provided at the junction of the valve body 40 and the screw 30 to facilitate sealing engagement of the valve body 40 with the screw 30. The second central bore 42 of the valve body 40 has internal threads 44 for threaded engagement with an adjustment nut 70 (described in more detail below) for the bearing assembly.

Referring now to fig. 4, fig. 4 is an enlarged view of encircled portion a of fig. 3 showing a schematic view of the bearing assembly. The bearing assembly may include a thrust bearing 10 for supporting rotation of the screw 30. The thrust bearing 10 is disposed at or near the first end 31 of the screw 30. The thrust bearing 10 is received in the second center hole 42 of the valve body 40, and abuts against the stepped portion 43 of the valve body 40 in the longitudinal direction. The thrust bearing 10 includes a bearing race, and bearing balls 12 that mate with the bearing race. The bearing races include a left half race 111 and a right half race 112. The left and right half raceways 111, 112 may be arranged symmetrically or asymmetrically with respect to each other. The right half seat 112 is closer to the stepped portion 43 of the valve body 40 than the left half seat 111 in the longitudinal direction. The left and right half-rings 111 and 112 are each provided with an outer raceway of the bearing 10 on the radially inner surface thereof. The two outer raceways are circular arc shaped and may be arranged with substantially the same radius. The radius of the outer race may be greater than the radius of the bearing ball 12.

The bearing assembly may also include a screw 30. The screw 30 is provided with an inner race corresponding to the outer race at a position where it supports the thrust bearing 10. The two inner raceways are circular arc shaped and may be arranged with substantially the same radius. The radius of the inner race may be greater than the radius of the bearing steel balls 12 and may be set to be the same as or different from the radius of the outer race.

As described above, the adjustment nut 70 is threaded into the second central bore 42 of the valve body 40 by the threaded engagement of the internal threads 44 of the second central bore 42 of the valve body 40 with the external threads 74 of the adjustment nut 70. The adjustment nut 70 is adjusted until the adjustment nut 70 abuts the left half race 111 of the thrust bearing 10 and the desired tightening torque is reached, whereby the thrust bearing 10 and the screw 30 are in an assembled state.

When the thrust bearing 10 is in an assembled state on the screw 30, the bearing balls 12 may be in contact with the outer raceways of the left and right half-rings 111, 112 and the inner raceway of the screw 30, thereby forming a four-point contact, as will be further described below with reference to fig. 5. In addition, the left and right half races 111 and 112 are closely fitted in the longitudinal direction, so that there is no gap in the longitudinal direction or in the axial direction of the thrust bearing 10 between the left and right half races 111 and 112. Further, the left and right half races 111, 112 may abut the valve body 40 in the radial direction of the thrust bearing 10 such that there is no gap between the left and right half races 111, 112 and the valve body 40 in the radial direction. The left and right race halves 111, 112 do not float in the radial direction, thereby eliminating or reducing the large radial forces imparted by the input shaft of the steering gear. The elimination or reduction of the radial force makes the seal ring in the valve body 40 less susceptible to wear, thereby avoiding problems of internal leakage and heavy turning. In addition, the elimination or reduction of the radial force also reduces the degree of wear at the seal between the input shaft of the steering gear and the oil seal, thereby avoiding the occurrence of external leakage.

The left and right half races 111 and 112 of the thrust bearing 10 and the bearing balls 12 may be assembled in a block assembly method. That is, prior to assembly, the left and right halves 111, 112, bearing balls 12, and/or screws 30 are screened and grouped at a certain level. For example, the bearing races may be divided into groups by the diameter dimension of their outer races, and the difference or level between the maximum and minimum diameter dimensions of the outer races of each group may be in the range 2 to 8 microns.

Table 1 below shows an example grouping of bearing races (i.e., left half race 111 and right half race 112), bearing balls 12, and screw 30. In this grouping example, for example, when the diameter of the outer race of the bearing race is at the Z4 level, different diameter bearing steel balls 12 may be selected for mating according to different diameter size ranges of the inner race of the screw (i.e., different screw levels), for example, the diameter of the bearing steel balls 12 may be the diameter Φd1 or the diameter Φd3, and so on.

In the case where there is no gap between the left and right half races 111, 112 in the longitudinal direction or in the axial direction of the thrust bearing 10, by the above-described grouping assembly, with a given class of bearing left and right half races, an accurate fit gap between the bearing race and the bearing balls 12 can be obtained taking only one parameter of the bearing ball diameter into consideration, thereby achieving a smaller steering gap. For example, according to the test, when the bearing race grade Z3 is selected, it is only necessary to select the diameter of the bearing ball with a diameter Φd3 so as to obtain a zero fit clearance between the bearing race and the bearing ball. In contrast, as described above, the prior art requires control of three parameters of the outer raceway diameter of the left and right half-races, the gap between the left and right half-races, and the diameter of the bearing steel ball itself at the same time, which is quite difficult in practical operation.

TABLE 1

Referring now to fig. 5, fig. 5 shows a schematic view of the engagement of the bearing balls 12 of the thrust bearing 10 with the bearing races. The bearing balls 12 contact the outer raceways of the left and right half-rings 111, 112 at first and second contact points 121, 122, respectively. The first contact point 111 and the second contact point 112 may be at an angle of about 45 ° with respect to the vertical with respect to the line connecting the center 123 of the bearing ball 12. In other embodiments, the included angle may be greater than 45 °, or less than 45 °. The vertical plane is perpendicular to the longitudinal direction and is shown in broken line form in fig. 5. In addition, the bearing steel ball 12 is also in contact with an inner race provided on the screw 30 at third and fourth contact points (not shown), and the line connecting the third and fourth contact points with the center 123 of the bearing steel ball 12 may be at an angle of about 45 ° with respect to the vertical plane. In other embodiments, the included angle may be greater than 45 °, or less than 45 °.

The left and right half-rings 111 and 112 may together form an outer-race chip flute 113 at a position where their respective outer races mutually engage, and the screw 30 is formed on its inner race with an inner-race chip flute 313 corresponding to the outer-race chip flute 113. The outer race chip flute 113 and the inner race chip flute 313 are each used to contain and store foreign matter that enters the thrust bearing to reduce friction caused by contact of the foreign matter with the bearing steel ball 12, the outer race or the inner race.

The thrust bearing 10 may optionally further include a cage 114. The cage 114 serves to prevent the bearing balls 12 from coming into contact with each other, thereby preventing the movement of the bearing balls 12 from affecting smooth rotation of the steering input shaft.

In the bearing assembly according to the present disclosure, when the thrust bearing 10 is in the assembled state on the screw 30, there is no gap between the left and right half races 111 and 112 in the axial direction of the thrust bearing 10, the right half race 112 abuts the stepped portion 43 of the valve body 40 in a gap-free manner, and the left half race 111 abuts the right half race in a gap-free manner. At this time, by the grouping assembly as described above, a desired fit clearance between the left and right half races 111 and 112 and the bearing balls 12 can be obtained. Then, when the adjustment nut 70 is screwed to tighten the thrust bearing 10, since there is no gap between the left and right half races 111, 112 in the axial direction of the thrust bearing 10, the pushing of the adjustment nut 70 against the left and right half races 111, 112 does not cause any change in the relative distance between the left and right half races 111, 112, so that the desired fit gap that has been obtained is easily maintained, and a small steering gap is obtained. In addition, since there is no gap between the left and right half races 111, 112 in the axial direction of the thrust bearing 10, the screwing of the adjustment nut 70 does not cause the left or right half races 111, 112 to be fully pressed against the bearing balls 12 when the tightening torque is large, so that the thrust bearing 10 cannot operate.

Although exemplary embodiments of the present disclosure have been described, it will be understood by those skilled in the art that various changes and modifications can be made to the exemplary embodiments of the present disclosure without departing from the spirit and scope of the disclosure. Accordingly, all changes and modifications are intended to be included within the scope of the present disclosure as defined by the appended claims. The disclosure is defined by the following claims, with equivalents of the claims to be included therein.

Claims (10)

1. A bearing assembly for a recirculating ball steering gear (100) in a steering system, the bearing assembly comprising:

A screw (30) having a first end (31) and an opposite second end (32), and

-A thrust bearing (10) provided on a first end (31) of the screw (30) and comprising a bearing race and a bearing ball (12);

wherein the bearing race comprises a left half-race (111) and a right half-race (112), the left half-race (111) and the right half-race (112) being provided with outer raceways, respectively, the screw (30) being provided with inner raceways at or near the first end (31) corresponding to the outer raceways of the left half-race (111) and the right half-race (112), respectively;

Wherein, when the thrust bearing (10) is in an assembled state on the screw (30), the bearing steel balls (12) are in contact with an outer race of the left half-race (111), an outer race of the right half-race (112), and an inner race of the screw (30), and the left half-race (111) and the right half-race (112) are in contact with each other in a gap-free manner in a longitudinal direction of the recirculating ball steering gear (100), thereby minimizing a steering gap of the steering system with a grouping assembly.

2. The bearing assembly according to claim 1, characterized in that the recirculating ball steering gear (100) further comprises a valve body (40) sealing an interior space (23) of the recirculating ball steering gear (100), and an adjusting nut (70) screwed into the valve body (40), wherein the left half-race (111) and the right half-race (112) abut the adjusting nut (70) and the valve body (40) in the longitudinal direction without play; and/or the left half-race (111) and the right half-race (112) abut the valve body (40) in the radial direction of the thrust bearing (10).

3. Bearing assembly according to claim 1, wherein the bearing steel balls (12) are in contact with the outer raceway of the left half-race (111) and the outer raceway of the right half-race (112) at a first contact point (121) and a second contact point (122), respectively, which are at an angle to a vertical plane perpendicular to the longitudinal direction, with respect to a line connecting the centers (123) of the bearing steel balls (12); and/or the included angle is about 45 °, greater than 45 °, or less than 45 °.

4. Bearing assembly according to claim 1, wherein the bearing steel ball (12) is in contact with the inner raceway of the screw (30) at a third contact point and a fourth contact point, respectively, the line connecting the third contact point and the fourth contact point with the centre of sphere (123) of the bearing steel ball (12) being at an angle with respect to a vertical plane perpendicular to the longitudinal direction; and/or the included angle is about 45 °, greater than 45 °, or less than 45 °.

5. The bearing assembly of claim 1, wherein the bearing races are configured to be grouped in the grouping assembly method by the diameter dimension of their outer races, the difference between the maximum and minimum of the diameter dimensions of the outer races of each group being in the range of 2 to 8 microns.

6. Bearing assembly according to any one of claims 1 to 5, wherein the outer raceways of the left and right half-races (111, 112) together form an outer raceway chip flute (113) at the location where they mutually engage; and/or an inner race chip groove (313) corresponding to the outer race chip groove (113) is formed on the inner race of the screw (30).

7. The bearing assembly according to any one of claims 1 to 5, wherein the thrust bearing (10) further comprises a cage (114), the cage (114) being configured such that no mutual contact between the bearing balls (12) occurs.

8. A recirculating ball steering gear (100), characterized in that the recirculating ball steering gear (100) comprises a bearing assembly according to any one of claims 1 to 7.

9. The recirculating ball steering gear (100) according to claim 8, wherein the recirculating ball steering gear (100) further comprises a valve body (40) configured to seal an interior space (23) of the recirculating ball steering gear (100), and/or the valve body (40) comprises a first central bore (41) and a second central bore (42) coaxially aligned; and the first center hole (41) and the second center hole (42) are connected by a step part (43); and/or the first central hole is close to the inner space (23) and the second central hole is close to the outside of the recirculating ball steering gear (100), and the diameter of the first central hole (41) is smaller than the diameter of the second central hole (42).

10. The recirculating ball steering gear (100) according to claim 9, wherein the valve body (40) is supported on the first end (31) of the screw (30) through the first central bore (41); and/or a thrust bearing (10) of the bearing assembly is received in the second central bore (42) of the valve body (40) and abuts the step (43) in a longitudinal direction without play; and/or the recirculating ball steering gear (100) further comprises an adjustment nut (70), the adjustment nut (70) being configured to be screwed into the second central bore (42) and to abut the left half-race (111) of the thrust bearing (10) without play.