Ball screw device for automobile

Abstract

The utility model provides a ball screw device for an automobile. The ball screw device comprises a ball screw, a ball nut, a ball return pipe upper petal, a ball return pipe lower petal, a ball return pipe clamp and balls. The ball nut is sleeved on the ball screw, the ball is arranged between the ball nut and the ball screw, the ball nut is provided with a ball return groove, the ball return pipe upper petal and the ball return pipe lower petal are arranged in the ball return groove, and the ball return pipe hoop is sleeved on the ball return pipe upper petal and the ball nut and clamps the ball return pipe upper petal and the ball return pipe lower petal; the ball return pipe clamp comprises a clamping force adjusting part, the clamping force adjusting part protrudes towards one side of the outer wall of the ball return pipe clamp, and the clamping force of the ball return pipe clamp is adjusted by adjusting the plastic deformation width of the clamping force adjusting part in the circumferential direction of the ball return pipe clamp. The problem that the ball return pipe is loosened due to large fluctuation of clamping force and poor consistency of the clamping force before and after the ball return pipe clamp is installed, and then the ball collides with the lip to generate noise is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile transmission and steering systems, in particular to a ball screw device for automobiles. Background Art

[0002] With the increasing popularity of new energy vehicles and high-end vehicles, ball screw assemblies are more suitable as transmission mechanisms in automotive electric power steering systems due to their large output force, wide coverage, and strong applicability. The automotive electric power steering system uses a ball screw to convert the motor power into screw translation to drive the tire rotation and achieve vehicle steering.

[0003] Existing automotive external circulation ball screws have certain drawbacks when used. Figure 1 As shown, the ball screw includes a ball screw 1', a nut 2', a bearing 3', a retaining ring 4', an upper return ball tube 5', a lower return ball tube 6', a non-standard clamp 7' and a ball 8'. The ball return tube formed by the upper return ball tube 5' and the lower return ball tube 6' is installed on the nut 2'. The ball return tube is mostly fixed to the nut 2' by a non-standard clamp 7' formed by stamping. The clamping force of the non-standard clamp 7' fluctuates greatly during installation, and the clamping force consistency of the non-standard clamp 7' before and after installation is poor. During the use of the ball screw, with the continuous impact and reciprocating motion of the ball 8', the holding force is easily attenuated, resulting in the upper return ball tube 5' and the lower return ball tube 6' being relatively loose, and the lip position on the lower return ball tube 6' moving back and forth relative to the positioning hole on the nut 2'. The continuous impact of the ball 8' on the lip will produce continuous irregular clicking sounds, resulting in loud noise.

[0004] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Utility Model Content

[0005] The utility model provides a ball screw device for automobiles, which is used to solve the problem that the non-standard clamps of existing ball screws have large fluctuations in clamping force before and after installation and poor consistency, causing the positions of upper and lower ball return tubes to become relatively loose, thereby causing the steel ball to hit the lip and generate noise.

[0006] The utility model provides a ball screw device for automobiles, comprising a ball screw, a ball nut, an upper petal of a ball return tube, a lower petal of a ball return tube, a ball return tube clamp and a ball;

[0007] The ball nut is sleeved on the ball screw, the ball is arranged between the ball nut and the ball screw, a ball return groove is opened on the ball nut, the upper petal of the ball return tube and the lower petal of the ball return tube are installed in the ball return groove, and the ball return tube clamp is sleeved on the upper petal of the ball return tube and the ball nut and clamps the upper petal of the ball return tube and the lower petal of the ball return tube;

[0008] Among them, the ball return tube clamp includes a clamping force adjustment part, which protrudes to one side of the outer wall of the ball return tube clamp. The clamping force of the ball return tube clamp is adjusted by adjusting the plastic deformation width of the clamping force adjustment part in the circumferential direction of the ball return tube clamp.

[0009] Optionally, when the plastic deformation width of the clamping force adjusting portion in the circumferential direction of the ball return tube clamp increases, the clamping force of the ball return tube clamp decreases; when the plastic deformation width of the clamping force adjusting portion in the circumferential direction of the ball return tube clamp decreases, the clamping force of the ball return tube clamp increases.

[0010] Optionally, the ball return tube clamp also includes a clamp body, which is tightly fitted with the upper lobe of the ball return tube and the outer wall of the ball nut, and the clamping force adjustment part is located on the side of the clamp body away from the ball nut.

[0011] Optionally, the clamping force adjustment portion is integrally formed with the clamp body.

[0012] Optionally, the clamping force adjustment portion includes a connecting piece and a first bent end and a second bent end located at both ends of the connecting piece, and the two ends of the connecting piece are respectively connected to the clamp body through the first bent end and the second bent end, and the plastic deformation width of the clamping force adjustment portion in the circumferential direction of the return tube clamp is adjusted by deforming the first bent end and the second bent end, thereby adjusting the clamping force of the return tube clamp.

[0013] Optionally, at least one recessed rib is provided on the connecting plate, and the recessed rib is used to increase the structural strength of the clamping force adjustment portion.

[0014] Optionally, a positioning recess is provided on one side surface of the ball return tube upper lobe facing the ball return tube clamp, and the ball return tube clamp is positioned on the outer wall of the ball return tube upper lobe and the ball nut through the positioning recess.

[0015] Optionally, it also includes a bearing and a bearing retaining ring, and the bearing is installed on the outer wall of the ball nut through the bearing retaining ring.

[0016] Optionally, a first helical raceway is provided on the outer wall of the ball screw, and a second helical raceway is provided on the inner wall of the ball nut, and the first helical raceway and the second helical raceway are combined to form an inner raceway for the ball to roll.

[0017] Optionally, a first positioning hole and a second positioning hole are provided on the outer wall of the ball nut, and the first positioning hole and the second positioning hole are both connected to the inner raceway. The upper lobe of the ball return tube and the lower lobe of the ball return tube are combined to form an outer raceway for the ball to roll on, and the two ends of the outer raceway are connected to the inner raceway through the first positioning hole and the second positioning hole respectively, and the ball rolls reciprocatingly in the inner raceway and the outer raceway.

[0018] The above technical solution of the utility model has the following beneficial effects:

[0019] The automobile ball screw device provided by the utility model has a clamping force adjustment part arranged on the outer wall of the ball return tube clamp. After the ball return tube clamp is installed on the outer wall of the ball nut and the upper lobe of the ball return tube, the clamping force of the ball return tube clamp can be adjusted by adjusting the plastic deformation width of the clamping force adjustment part in the circumferential direction of the ball return tube clamp, thereby achieving a stable and controllable clamping force of the ball return tube clamp, which is durable and does not decay, and solves the problem that the upper lobe and the lower lobe of the ball return tube are relatively loose due to large clamping force fluctuations and poor clamping force consistency before and after installation of the ball return tube clamp, thereby causing the ball to hit the lip to generate noise. In addition, the utility model also reduces the manufacturing cost of the ball screw and lowers the threshold for ball screw manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a structural schematic diagram of an existing ball screw device;

[0022] Figure 2 A schematic diagram of the structure of a ball screw device provided in an embodiment of the utility model;

[0023] Figure 3 for Figure 2 The structural schematic diagram of the ball return pipe clamp shown in ;

[0024] Figure 4 for Figure 3 Schematic diagram of the structure of the ball return pipe clamp before and after bending deformation shown in ;

[0025] Figure 5 for Figure 3 A schematic diagram of the structure of the concave rib of the ball return pipe clamp shown in ;

[0026] Figure 6 for Figure 2 The schematic diagram of the structure of the upper valve of the return ball tube and the lower valve of the return ball tube shown in ;

[0027] Figure 7 for Figure 2 Schematic diagram of the structure of the ball nut shown in .

[0028] Reference numerals:

[0029] 1. Ball screw; 2. Ball nut; 3. Bearing; 4. Bearing retaining ring; 5. Upper petal of ball return tube; 6. Lower petal of ball return tube; 7. Ball return tube clamp; 8. Ball; 9. Positioning depression; 21. Ball return groove; 71. Clamping force adjustment part; 72. Clamp body; 711. Connecting piece; 712. First bent end; 713. Second bent end; 714. Concave rib. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] Combine the following Figures 2 to 7 The ball screw device for automobile provided by the utility model is described in detail.

[0032] See also Figure 2 The utility model provides a ball screw device for an automobile, comprising a ball screw 1, a ball nut 2, a bearing 3, a bearing retaining ring 4, an upper petal 5 of a ball return tube, a lower petal 6 of a ball return tube, a ball return tube clamp 7 and a ball 8.

[0033] The ball nut 2 is sleeved on the ball screw 1, and the ball 8 is arranged between the ball nut 2 and the ball screw 1. The bearing 3 is installed on the outer wall of the ball nut 2 through the bearing retaining ring 4. The bearing 3 can provide support for the ball nut 2 to rotate around the ball screw 1, and the bearing retaining ring 4 can prevent the bearing 3 from loosening relative to the ball nut 2. A ball return groove 21 is provided on the ball nut 2, and the upper petal 5 and the lower petal 6 of the ball return tube are installed in the ball return groove 21, and the upper petal 5 of the ball return tube is located above the lower petal 6 of the ball return tube, and the upper petal 5 and the lower petal 6 of the ball return tube are combined to form a ball return tube. The ball return tube clamp 7 is sleeved on the upper petal 5 of the ball return tube and the ball nut 2 and clamps the upper petal 5 and the lower petal 6 of the ball return tube. The ball return tube clamp 7 simultaneously holds the upper petal 5 of the ball return tube and the outer wall of the ball nut 2, which can prevent the ball return tube from loosening relative to the ball nut 2.

[0034] Among them, a first helical raceway is provided on the outer wall of the ball screw 1, and a second helical raceway is provided on the inner wall of the ball nut 2. The first helical raceway and the second helical raceway are combined to form an inner raceway for the balls 8 to roll. A first positioning hole and a second positioning hole are provided on the outer wall of the ball nut 2. Both the first positioning hole and the second positioning hole are connected to the inner raceway. The upper petal 5 and the lower petal 6 of the ball return tube are combined to form an outer raceway for the balls 8 to roll, and the two ends of the outer raceway are connected to the inner raceway through the first positioning hole and the second positioning hole respectively. The balls 8 roll back and forth in the inner raceway and the outer raceway to transmit the relative motion between the ball screw 1 and the ball nut 2.

[0035] See also Figure 2 and Figure 3 The ball return tube clamp 7 includes a clamping force adjusting portion 71, which protrudes toward one side of the outer wall of the ball return tube clamp 7. The clamping force of the ball return tube clamp 7 is adjusted by adjusting the plastic deformation width of the clamping force adjusting portion 71 in the circumferential direction of the ball return tube clamp 7, thereby reducing the defective rate of parts caused by poor consistency of the holding force (clamping force) of the ball return tube clamp 7 during the installation process, and achieving stable positioning between the ball nut 2 and the ball return tube.

[0036] Specifically, when the plastic deformation width d of the clamping force adjustment part 71 in the circumferential direction of the ball return tube clamp 7 increases, the clamping force of the ball return tube clamp 7 decreases; when the plastic deformation width d of the clamping force adjustment part 71 in the circumferential direction of the ball return tube clamp 7 decreases, the clamping force of the ball return tube clamp 7 increases.

[0037] The ball return tube clamp 7 can be made of soft stainless steel 304, which can effectively prevent the ball return tube from being clamped insufficiently relative to the ball nut 2.

[0038] The ball return tube clamp 7 further comprises a clamp body 72 , which is tightly fitted with the ball return tube upper petal 5 and the outer wall of the ball nut 2 , and the clamping force adjustment portion 71 is located on the side of the clamp body 72 away from the ball nut 2 .

[0039] In one embodiment, the clamping force adjustment portion 71 and the clamp body 72 are integrally formed.

[0040] See also Figure 4, the clamping force adjusting part 71 includes a connecting piece 711 and a first bending end 712 and a second bending end 713 located at both ends of the connecting piece 711. Both ends of the connecting piece 711 are connected to the clamp body 72 through the first bending end 712 and the second bending end 713 respectively. By deforming the first bending end 712 and the second bending end 713, the plastic deformation width of the clamping force adjusting part 71 in the circumferential direction of the return ball tube clamp 7 is adjusted, so as to adjust the clamping force of the return ball tube clamp 7. Among them, the connecting piece 711, the first bending end 712 and the second bending end 713 are integrally formed. Specifically, the clamping force of the return ball tube clamp 7 can be reduced by increasing the plastic deformation width of the first bending end 712 and the second bending end 713 in the circumferential direction of the return ball tube clamp 7, and the clamping force of the return ball tube clamp 7 can be increased by reducing the plastic deformation width of the first bending end 712 and the second bending end 713 in the circumferential direction of the return ball tube clamp 7.

[0041] Among them, Figure 4 The width of the first bending end 712 and the second bending end 713 shown in is d1 before deformation, and the width of the first bending end 712 and the second bending end 713 after deformation is d2, d2 < d1, and both d1 and d2 are greater than 0.

[0042] Further, please refer to Figure 5 , at least one concave rib 714 is provided on the connecting piece 711. The concave rib 714 is used to increase the structural strength of the clamping force adjusting part 71, that is, the concave rib 714 functions as a reinforcing rib. When the ball nut 2 and the return ball tube are affected by thermal expansion and contraction or mechanical vibration, the clamping force adjusting part 71 can improve the clamping force of the return ball tube clamp 7 or play an adjusting effect similar to that of a spring, so that the return ball tube clamp 7 can always adapt to the clamping requirements of the ball nut 2 and the return ball tube, thus ensuring a continuous and effective clamping effect and reducing the noise caused by the looseness of the return ball tube due to poor holding force persistence.

[0043] Further, please refer to Figure 6 and Figure 7 , a positioning recess 9 is provided on the surface of the upper flap 5 of the return ball tube facing the return ball tube clamp 7. The positioning recess 9 is used to provide a stable force application surface for the return ball tube clamp 7. The return ball tube clamp 7 is positioned on the outer walls of the upper flap 5 of the return ball tube and the ball nut 2 through the positioning recess 9, and the inner wall of the return ball tube clamp 7 presses the upper flap 5 of the return ball tube, the upper flap 5 of the return ball tube presses the lower flap 6 of the return ball tube, and the lower flap 6 of the return ball tube presses the bottom of the return groove 21 of the ball nut 2. In this way, there is no easy gap between the whole return ball tube and the ball nut 2, resulting in noise.

[0044] Among them, a lip structure is fixed on the lower flap 6 of the return ball tube, and the lip structure and the inner raceway are smoothly transitioned at the connection.

[0045] In one embodiment, the upper petal 5 and the lower petal 6 of the ball return tube are both made of plastic PA66 reinforced with glass fiber, thereby improving the strength and wear resistance of the ball return tube.

[0046] The ball return tube clamp of the ball screw device of the utility model has the advantages of quick and easy installation, visual installation effect, stable and controllable holding force, and long-lasting holding force without attenuation. It reduces the defective rate of parts caused by poor consistency of holding force during the installation process, reduces the manufacturing cost of the ball screw, and lowers the threshold for ball screw manufacturing; it also reduces the noise caused by the loosening of the ball return tube due to poor holding force durability.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A ball screw device for an automobile, characterized in that: It comprises a ball screw (1), a ball nut (2), an upper flap of a ball return tube (5), a lower flap of a ball return tube (6), a ball return tube clamp (7) and a ball (8); The ball nut (2) is sleeved on the ball screw (1), the ball (8) is arranged between the ball nut (2) and the ball screw (1), a ball return groove (21) is provided on the ball nut (2), the upper petal (5) of the ball return tube and the lower petal (6) of the ball return tube are installed in the ball return groove (21), and the ball return tube clamp (7) is sleeved on the upper petal (5) of the ball return tube and the ball nut (2) and clamps the upper petal (5) of the ball return tube and the lower petal (6) of the ball return tube; The ball return tube clamp (7) comprises a clamping force adjusting portion (71), and the clamping force adjusting portion (71) protrudes toward one side of the outer wall of the ball return tube clamp (7). The clamping force of the ball return tube clamp (7) is adjusted by adjusting the plastic deformation width of the clamping force adjusting portion (71) in the circumferential direction of the ball return tube clamp (7).

2. The automotive ball screw device according to claim 1, characterized in that: When the plastic deformation width of the clamping force adjusting portion (71) in the circumferential direction of the ball return tube clamp (7) increases, the clamping force of the ball return tube clamp (7) decreases; when the plastic deformation width of the clamping force adjusting portion (71) in the circumferential direction of the ball return tube clamp (7) decreases, the clamping force of the ball return tube clamp (7) increases.

3. The automotive ball screw device according to claim 2, characterized in that: The ball return tube clamp (7) also includes a clamp body (72), the clamp body (72) is tightly fitted with the upper petal (5) of the ball return tube and the outer wall of the ball nut (2), and the clamping force adjustment part (71) is located on the side of the clamp body (72) away from the ball nut (2).

4. The automotive ball screw device according to claim 3, characterized in that: The clamping force adjustment portion (71) and the clamp body (72) are integrally formed.

5. The automotive ball screw device according to claim 3, characterized in that: The clamping force adjusting portion (71) includes a connecting piece (711) and a first bent end (712) and a second bent end (713) located at both ends of the connecting piece (711). The two ends of the connecting piece (711) are connected to the clamp body (72) via the first bent end (712) and the second bent end (713), respectively. The plastic deformation width of the clamping force adjusting portion (71) in the circumferential direction of the return tube clamp (7) is adjusted by deformation of the first bent end (712) and the second bent end (713), thereby adjusting the clamping force of the return tube clamp (7).

6. The automotive ball screw device according to claim 5, characterized in that: At least one recessed rib (714) is provided on the connecting piece (711), and the recessed rib (714) is used to increase the structural strength of the clamping force adjustment portion (71).

7. The automotive ball screw device according to claim 1, characterized in that: A positioning recess (9) is provided on the surface of the ball return tube upper flap (5) facing the ball return tube clamp (7), and the ball return tube clamp (7) is positioned on the outer wall of the ball return tube upper flap (5) and the ball nut (2) through the positioning recess (9).

8. The automotive ball screw device according to claim 1, characterized in that: It also comprises a bearing (3) and a bearing retaining ring (4), wherein the bearing (3) is mounted on the outer wall of the ball nut (2) via the bearing retaining ring (4).

9. The automotive ball screw device according to claim 1, characterized in that: A first helical raceway is provided on the outer wall of the ball screw (1), and a second helical raceway is provided on the inner wall of the ball nut (2); the first helical raceway and the second helical raceway are combined to form an inner raceway for the balls (8) to roll.

10. The automotive ball screw device according to claim 9, characterized in that: The outer wall of the ball nut (2) is provided with a first positioning hole and a second positioning hole, the first positioning hole and the second positioning hole are both connected to the inner raceway, the upper lobe (5) of the ball return tube and the lower lobe (6) of the ball return tube are combined to form an outer raceway for the ball (8) to roll, and the two ends of the outer raceway are respectively connected to the inner raceway through the first positioning hole and the second positioning hole, and the ball (8) rolls back and forth in the inner raceway and the outer raceway.

Images