Ball nut assembly on automobile steering device

Abstract

A ball nut assembly on an automobile steering gear comprises a ball nut installed on a transmission lead screw of a steering gear box and a ball reverser installed in the ball nut, an inner spiral raceway is arranged on the wall face of an inner hole of the ball nut, and the inner spiral raceway is matched with an outer spiral raceway of the transmission lead screw. The wall face of an inner hole of the ball nut is further provided with a mounting slot, the mounting slot extends in the axial direction, the two ends of the mounting slot are communicated, the mounting slot enables the inner spiral raceway to be divided into a plurality of raceways which are not communicated, the ball reverser is inserted into the mounting slot, and the front wall face of the ball reverser is further provided with a plurality of ball returning channels. And two ends of each ball return channel are respectively communicated with two adjacent roller paths to form a closed circulation loop. The rolling ball circulation device can achieve circulation of rolling balls more reasonably, and is simple in overall structure, convenient to produce and high in production efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile parts, and particularly relates to a ball nut assembly on an automobile steering gear. Background Art

[0002] The steering gear, commonly known as the steering gear, is the most important part for the steering function of an automobile and an important guarantee for the driving safety of the automobile. Mechanical steering gears are widely used. According to their different structural characteristics, they can be divided into rack and pinion steering gears, recirculating ball steering gears, worm and roller steering gears, worm and finger pin steering gears, etc.

[0003] Among them, the recirculating ball steering gear is composed of a transmission screw rod and a ball nut with balls installed in a spiral groove formed jointly by them. The advantages of the recirculating ball steering gear are: because there are balls that can circulate between the transmission screw rod and the ball nut, the sliding friction is changed into rolling friction, so the transmission efficiency can reach 75% - 85%. However, in this circulation mode, the structure of the spiral ball track of the ball nut is complex and difficult to manufacture, resulting in low production efficiency. Content of the Utility Model

[0004] Aiming at the above-mentioned shortcomings of the existing technology, the purpose of the utility model is to provide a ball nut assembly on an automobile steering gear, which can more reasonably realize the circulation of the balls, has a simple overall structure, is convenient for production, and has high production efficiency.

[0005] The technical solution adopted by the utility model to solve its technical problems is that a ball nut assembly on an automobile steering gear includes a ball nut installed on the transmission screw rod of the steering gear and a ball returner installed in the ball nut. An inner spiral raceway is provided on the inner hole wall surface of the ball nut, and the inner spiral raceway cooperates with the outer spiral raceway of the transmission screw rod. An installation slot is also provided on the inner hole wall surface of the ball nut. The installation slot extends axially and penetrates at both ends. The installation slot divides the inner spiral raceway into multiple non-connected raceways. The ball returner is inserted into the installation slot. A plurality of ball return channels are also provided on the front wall surface of the ball returner, and both ends of each ball return channel are respectively communicated with two adjacent raceways and form a closed circulation loop.

[0006] Advantages of adopting the above technical solution: The installation slots are provided, so that the inner spiral raceway is divided into multiple non-connected raceways. Then, through an external positioning fixture, the ball retainer forms a fit with the installation slots of the ball nut. After being installed in place, the ball return channels on the ball retainer can connect two adjacent raceways and form a closed circulation loop, enabling the balls to roll in a cycle. Therefore, the combination of the ball nut and the ball retainer with the above structure can more reasonably achieve the purpose of ball circulation, and the overall structure is simple. The processing of the inner spiral raceway and the ball return channels is also convenient. Therefore, the overall production is more convenient and the production efficiency is higher.

[0007] Further, both side walls of the installation slot are set as first fitting walls, and the distance between the first fitting walls gradually decreases in the direction towards the transmission screw rod to form an inverted cone structure. The corresponding side walls of the ball retainer are set as second fitting walls, and the second fitting walls are in contact with the first fitting walls.

[0008] Advantages of adopting the above technical solution: After the ball retainer is inserted in place, since the two first fitting walls form an inverted cone structure, the first fitting walls will tightly fit with the second fitting walls, and the ball retainer is not prone to radial loosening after installation, with a more reasonable structural design.

[0009] Further, the bottom wall of the installation slot is set as a third fitting wall, and the rear wall surface of the ball retainer is set as a fourth fitting wall. The third fitting wall and the fourth fitting wall are in contact with each other and are both set as arc-shaped with the same curvature as the front wall surface of the ball retainer.

[0010] Advantages of adopting the above technical solution: The shapes of the third fitting wall and the fourth fitting wall are reasonably set. After the ball retainer is inserted in place, the third fitting wall can form a good and tight fit with the fourth fitting wall, making the installation of the ball retainer more stable. At the same time, the middle part of the ball return channel is consistent with the overall thickness of the ball retainer, thereby increasing the stability of the ball rolling.

[0011] Further, there are also provided paired convex blocks on the front wall surface of the ball retainer. The convex blocks are respectively distributed on the outer sides of both ends of the ball return channel and are located at the corresponding outlets of the raceway.

[0012] Advantages of adopting the above technical solution: The provision of the tightening ribs makes the fit between the ball retainer and the installation slot closer. At the same time, the tightening ribs adopt an axially extending structure, facilitating the installation of the ball retainer with a reasonable structural design.

[0013] Further, there are also provided paired convex blocks on the front wall surface of the ball retainer. The convex blocks are respectively distributed on the outer sides of both ends of the ball return channel and are located at the corresponding outlets of the raceway.

[0014] Advantages of adopting the above technical solution: Due to the provision of the installation slots, two outlets will be formed on each of the formed raceways, and one of the outlets is communicated through the ball return channel. Therefore, the provision of the bumps can prevent the balls from escaping from the other two outlets of the inner spiral raceway during the rotation of the ball nut relative to the transmission screw rod.

[0015] Furthermore, the corresponding side wall surface of the bump abuts against the wall surface of the ball return channel.

[0016] Advantages of adopting the above technical solution: The bumps can also provide protection for the rolling of the balls, preventing the phenomenon that the balls rush out of the ball return channel due to inertia at the corners.

[0017] Furthermore, the ball returner is made by the injection powder alloy sintering process.

[0018] Advantages of adopting the above technical solution: The ball returner made of the above material has properties such as wear resistance, resistance to high and low temperatures, and high strength, and can ensure dimensional tolerances while being more reasonably designed. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the overall structure of the present utility model in cooperation with the transmission screw rod;

[0020] Figure 2 It is a cross-sectional view of the overall structure of the present utility model;

[0021] Figure 3 It is a schematic diagram of the structure of the ball nut of the present utility model;

[0022] Figure 4 It is a schematic diagram of the structure of the ball returner of the present utility model;

[0023] Figure 5 It is another view of the structure of the ball returner of the present utility model;

[0024] Figure 6 It is another view of the structure of the ball returner of the present utility model.

[0025] In the figure: 1 - transmission screw rod, 2 - ball nut, 3 - ball returner, 4 - inner spiral raceway, 5 - installation slot, 6 - ball return channel, 7 - circulation loop, 8 - first fitting wall, 9 - second fitting wall, 10 - third fitting wall, 11 - fourth fitting wall, 12 - tightening rib, 13 - bump. Detailed Embodiments

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention and / or the prior art, the following will describe the specific embodiments of the present invention with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other embodiments can also be obtained. Additionally, the terms related to directions only represent the relative positional relationships between components, rather than absolute positional relationships.

[0027] Please refer to Figures 1 to 6 As shown, a ball nut assembly on an automotive steering gear includes a ball nut 2 installed on a transmission lead screw 1 of a steering gear, and a ball returner 3 installed in the ball nut 2. An internal spiral raceway 4 is provided on the inner hole wall surface of the ball nut 2, and the internal spiral raceway 4 cooperates with the external spiral raceway of the transmission lead screw 1. An installation slot 5 is also provided on the inner hole wall surface of the ball nut 2. The installation slot 5 extends axially and penetrates at both ends. The installation slot 5 divides the internal spiral raceway into multiple non-connected raceways. The ball returner 3 is inserted into the installation slot 5. A plurality of ball return channels 6 are provided on the front wall surface of the ball returner 3, and both ends of each ball return channel 6 communicate with two adjacent raceways respectively, forming a closed circulation loop 7. The setting of the installation slot 5 makes the internal spiral raceway 4 divided into multiple non-connected raceways, and both ends of each raceway form exits at the installation slot 5. Then, through an external positioning jig, the ball returner 3 is fitted with the installation slot 5 of the ball nut 2. After being installed in place, the ball return channels 6 on the ball returner 3 can connect two adjacent raceways. It should be noted that two adjacent raceways form a pair. The upper opening of the ball return channel 6 communicates with the right or left exit of the upper raceway, and the lower opening of the ball return channel 6 communicates with the left or right exit of the lower raceway. In this way, the rolling of the balls can form a cycle. Therefore, the combination of the ball nut 2 and the ball returner 3 with the above structure can more reasonably achieve the purpose of ball circulation, and the overall structure is also simple. The processing of the internal spiral raceway 4 and the ball return channels 6 is also convenient. Therefore, the overall production is more convenient and the production efficiency is higher.

[0028] In this embodiment, the two side walls of the installation slot 5 are set as first fitting walls 8, and the distance between the first fitting walls 8 gradually decreases in the direction towards the transmission lead screw 1 to form an inverted cone structure. The corresponding side walls of the ball returner 3 are set as second fitting walls 9, and the second fitting walls 9 are fitted with the first fitting walls 8. After the ball returner 3 is inserted in place, since the two first fitting walls 8 form an inverted cone structure, the first fitting walls 8 will tightly fit with the second fitting walls 9, and at the same time, the ball returner 3 is not prone to radial loosening after installation, and the structural design is more reasonable.

[0029] In this embodiment, the bottom wall of the installation slot 5 is set as the third fitting wall 10, and the rear wall surface of the ball returner 3 is set as the fourth fitting wall 11. The third fitting wall 10 and the fourth fitting wall 11 are fitted to each other and are both set as arc-shaped with the same curvature as the front wall surface of the ball returner 3. The shapes of the third fitting wall 10 and the fourth fitting wall 11 are reasonably set. After the ball returner 3 is inserted in place, the third fitting wall 10 can form a good tight fit with the fourth fitting wall, making the installation of the ball returner 3 more stable. At the same time, the thickness of the return ball channel 6 is consistent with the overall thickness of the ball returner 3, thereby increasing the stability of the ball rolling.

[0030] In this embodiment, a tightening rib 12 is further provided on the surface of the fourth fitting wall 11. A plurality of tightening ribs 12 are provided and are axially extended. The setting of the tightening ribs 12 makes the fit between the ball returner 3 and the installation slot 5 closer. At the same time, the tightening ribs 12 adopt an axially extended structure, which is convenient for the installation of the ball returner 3 and the structural design is reasonable.

[0031] In this embodiment, a pair of convex blocks 14 are further provided on the front wall surface of the ball returner 3. The convex blocks 14 are respectively distributed outside both ends of the return ball channel 6 and are located at the corresponding outlets of the raceway. Due to the setting of the installation slot 5, two outlets are formed in each raceway in the installation slot 5. One of the outlets of two adjacent raceways is connected through the return ball channel 6, and the two convex blocks 14 exactly correspond to the other two outlets. Therefore, through the setting of the convex blocks 14, it can be avoided that during the rotation of the ball nut 2 relative to the transmission screw 1, the balls do not escape from the other two missing outlets of the raceway.

[0032] In this embodiment, the corresponding side wall surface of the convex block 14 abuts against the wall surface of the return ball channel 6. With such a setting, the convex block 14 can also provide protection for the rolling of the balls, avoiding the phenomenon that the balls rush out of the return ball channel 6 due to inertia at the corner, and the use of the convex block 14 is more reasonable.

[0033] In this embodiment, the ball returner 3 is made by injection powder alloy sintering process. The ball returner 3 made of the above material has properties such as wear resistance, high and low temperature resistance, and high strength, and can ensure dimensional tolerances at the same time, and the design is more reasonable.

[0034] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A ball nut assembly on an automotive steering gear, characterized in that: It includes a ball nut (2) installed on a transmission lead screw (1) of a steering gear, and a ball returner (3) installed in the ball nut (2). An inner spiral raceway (4) is provided on the inner hole wall surface of the ball nut (2), and the inner spiral raceway (4) cooperates with the outer spiral raceway of the transmission lead screw (1). An installation slot (5) is further provided on the inner hole wall surface of the ball nut (2), and the installation slot (5) extends axially and penetrates at both ends. The installation slot (5) divides the inner spiral raceway (4) into a plurality of non-connected raceways. The ball returner (3) is inserted into the installation slot (5). A plurality of ball return channels (6) are further provided on the front wall surface of the ball returner (3), and both ends of each ball return channel (6) are respectively communicated with two adjacent raceways and form a closed circulation loop (7).

2. The ball nut assembly on an automotive steering gear according to claim 1, characterized in that: Both side walls of the installation slot (5) are set as first fitting walls (8), and the distance between the first fitting walls (8) gradually decreases in the direction towards the transmission lead screw (1) to form an inverted cone structure. The corresponding side walls of the ball returner (3) are set as second fitting walls (9), and the second fitting walls (9) are fitted with the first fitting walls (8).

3. A ball nut assembly on an automotive steering gear according to claim 2, characterized in that: The bottom wall of the installation slot (5) is set as a third fitting wall (10), and the rear wall surface of the ball returner (3) is set as a fourth fitting wall (11). The third fitting wall (10) and the fourth fitting wall (11) are fitted and set as an arc shape consistent with the radian of the front wall surface of the ball returner (3).

4. The ball nut assembly on an automotive steering gear according to claim 3, characterized in that: A plurality of pressing ribs (12) are further provided on the surface of the fourth fitting wall (11), and the pressing ribs (12) are provided in plurality and extend axially.

5. A ball nut assembly on an automotive steering gear according to claim 1, characterized in that: A pair of convex blocks (13) are further provided on the front wall surface of the ball returner (3), and the convex blocks (13) are respectively distributed outside both ends of the ball return channel (6) and are located at the corresponding outlets of the raceway.

6. The ball nut assembly on an automotive steering gear according to claim 5, characterized in that: The corresponding side wall surfaces of the convex blocks (13) are in contact with the wall surfaces of the ball return channel (6).

7. A ball nut assembly on an automotive steering gear according to claim 1, characterized in that: The ball returner (3) is made by an injection powder alloy sintering process.

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