Anti-locking structure of ball screw unit

Abstract

The utility model discloses an anti-locking structure of a ball screw unit, which relates to the field of ball screws and comprises a screw, a nut and balls, one end of the screw is a motor connecting end, the other end of the screw is a piston connecting end and is used for sleeving a piston, the piston is fixed on the nut, and the nut is rotatably matched on the screw through a plurality of balls; the motor connecting end is provided with a motor interface matching surface used for assembling a motor rotor, one side, close to the motor interface matching surface, of the nut is a front end face, the front end face is provided with a nut protrusion, the outer wall of the lead screw extends outwards in the radial direction to form a lead screw protrusion, and the lead screw protrusion is located between the motor interface matching surface and the front end face. The lead screw protrusion is used for being matched with the nut protrusion so as to stop the front end face. The anti-locking structure of the ball screw is optimized from a motor product and a ball screw product to a ball screw product, the lead screw is installed on the motor without considering forward and reverse directions, and the reliability of a system and the development efficiency of the product are improved.

Description

Technical Field

[0001] The utility model relates to the field of ball screws, in particular to an anti-locking structure of a ball screw unit. Background Art

[0002] A ball screw is a transmission component that can convert spiral motion and linear motion in both directions. Its structure mainly includes a nut, a screw, a rolling element, etc. It has the characteristics of high precision, reversibility and high efficiency, and is widely used in automobiles, CNC machine tools and robots.

[0003] In the automotive field, ball screws are mainly used in electric power steering systems, electronic mechanical brake calipers, and steer-by-wire systems. Ball screws are usually connected to a motor at one end and a piston at the other end. When the system is initialized or in extreme working conditions such as when the motor is powered off, the nut (2') will reverse relative to the screw (1'). At the extreme position, the contact between the surfaces of the two parts will generate huge friction. If the nut is required to rotate forward relative to the screw, the two surfaces may not be able to separate in time due to friction, resulting in friction lock. In order to avoid this situation, protrusions are usually set on the motor and the nut. During reversal, the two protrusions contact first to prevent the two planes from contacting each other. For example Figure 1 shown.

[0004] However, the mating surfaces of the lead screw and the motor interface are symmetrical structures. If they are installed 180 degrees in reverse, when the system is initialized or reversed under extreme working conditions such as motor power failure, the nut protrusion (3') will not contact the motor rotor protrusion (4'), but will first contact the motor rotor assembly surface (5') on the inner wall of the motor rotor (6'), causing friction locking, and the product may not work properly.

[0005] In addition, the position and size design of the protrusion are crucial. Ball screws and motors are usually designed by different manufacturers. Product engineers need to work with different manufacturers, which makes the design inefficient and prone to errors. Utility Model Content

[0006] The purpose of the utility model is to overcome the deficiencies of the prior art and to provide an anti-locking structure for a ball screw unit, thereby reducing the risk of product failure caused by reverse installation of the screw, while simplifying the design process of the anti-locking structure and improving design efficiency.

[0007] The purpose of the utility model is achieved through the following technical solutions: this ball screw unit anti-locking structure includes a screw, a nut and a ball, one end of the screw is a motor connection end, and the other end of the screw is a piston connection end, which is used to sleeve a piston, and the piston is fixed on the nut, and the nut is rotatably matched with the screw through a number of balls; a motor interface matching surface is provided on the motor connection end for assembling the motor rotor, and the side of the nut close to the motor interface matching surface is the front end face, and a nut protrusion is provided on the front end face, and a screw protrusion is formed on the outer wall of the screw extending radially outward, and the screw protrusion is located between the motor interface matching surface and the front end face, and the screw protrusion is used to match the nut protrusion, thereby blocking the front end face.

[0008] As a further technical solution, the distance between the outermost edge of the screw protrusion and the screw axis is greater than the distance between the innermost edge of the nut protrusion and the screw axis.

[0009] As a further technical solution, a gap is provided between the lead screw protrusion and the motor rotor assembly surface on the inner wall of the motor rotor.

[0010] As a further technical solution, an external thread is provided on the side of the nut away from the front end surface for connecting with the piston.

[0011] As a further technical solution, the shapes, positions and sizes of the lead screw protrusion and the nut protrusion are adjusted according to actual working conditions.

[0012] The beneficial effects of the utility model are:

[0013] 1. The protrusion originally set on the motor rotor is changed to be set on the lead screw, which reduces the risk of product locking due to incorrect assembly of the lead screw and motor interface, and improves product design efficiency;

[0014] 2. There is no need to consider the positive and negative assembly of the screw and the motor, which avoids product failure due to reverse installation and improves assembly efficiency to a certain extent;

[0015] 3. When designing the product, the anti-lock function is concentrated from the motor and the ball screw to the ball screw alone, eliminating the need to contact the motor manufacturer, which improves product design efficiency and reduces the risk of information transmission errors;

[0016] 4. After assembly with the motor, a gap is formed between the screw protrusion and the motor rotor assembly surface to further prevent the friction locking phenomenon between the two surfaces caused by the reverse rotation of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure after the prior art and the motor are assembled.

[0018] Figure 2It is a three-dimensional structural schematic diagram of the utility model.

[0019] Figure 3 It is a schematic diagram of the main structure of the utility model.

[0020] Figure 4 for Figure 3 AA section view.

[0021] Figure 5 for Figure 3 BB cross-sectional view.

[0022] Figure 6 It is a schematic diagram of the structure after the utility model is assembled with a motor.

[0023] Figure 7 for Figure 6 A partial enlarged schematic diagram of the C area in the middle.

[0024] Explanation of the accompanying drawings: screw 1, motor connecting end 11, piston connecting end 12, motor interface mating surface 13, screw protrusion 14, nut 2, nut protrusion 21, front end surface 22, external thread 23, ball 3, piston 4, motor rotor 5, motor rotor assembly surface 51, gap 6. DETAILED DESCRIPTION

[0025] The utility model will be described in detail below with reference to the accompanying drawings:

[0026] Example: As attached Figures 2 to 6 As shown, the anti-locking structure of the ball screw unit includes a screw 1, a motor connecting end 11, a piston connecting end 12, a motor interface mating surface 13, a screw protrusion 14, a nut 2, a nut protrusion 21, a front end face 22, an external thread 23, a ball 3, a piston 4, a motor rotor 5, a motor rotor assembly surface 51 and a gap 6.

[0027] Reference Figure 2 , 4 The left side of the lead screw 1 is the motor connection end 11, and the motor interface mating surface 13 is symmetrically arranged on the motor connection end 11, and the motor interface mating surface 13 can be inserted into the motor rotor 5. The left side of the nut 2 (i.e., the side close to the motor interface mating surface 13) is the front end face 22, and a nut protrusion 21 is arranged on the front end face 22. In addition, a lead screw protrusion 14 is formed on the outer wall of the lead screw 1 to extend (protrude) radially outward, and the lead screw protrusion 14 is located between the motor interface mating surface 13 and the front end face 22. When the motor is relatively reversed so that the front end face 22 moves toward the motor rotor assembly surface 51, the lead screw protrusion 14 cooperates with the nut protrusion 21 to lock the nut 2, thereby preventing the front end face 22 from approaching the motor rotor assembly surface 51.

[0028] like Figure 6As shown, the right side of the screw 1 is the piston connecting end 12, and the piston 4 is sleeved on the outer periphery of the piston connecting end 12. At the same time, the mouth of the piston 4 is connected and fixed to the external thread 23 on the nut 2. The external thread 23 is arranged on the right side of the nut 2 (the side away from the front end face 22), and the nut 2 is relatively rotated on the screw 1 through a plurality of balls 3.

[0029] Further, such as Figure 3 As shown, the distance D1 between the outermost edge of the screw protrusion 14 and the axis of the screw 1 is greater than the distance D2 between the innermost edge of the nut protrusion 21 and the axis of the screw 1. This ensures that when the motor reverses, the screw protrusion 14 can contact and block the nut protrusion 21.

[0030] Reference Figure 6 , 7 A gap 6 is set between the screw protrusion 14 and the motor rotor assembly surface 51 on the inner wall of the motor rotor 5. The existence of the gap 6 provides a space for accommodating the nut 2 when the motor is reversed, further avoiding friction locking between the motor rotor assembly surface 51 and the front end surface 22.

[0031] As a preferred technical solution, the shapes, positions and sizes of the screw protrusion 14 and the nut protrusion 21 are adjusted according to the actual working conditions. In this embodiment, the screw protrusion 14 is triangular, and the nut protrusion 21 is fan-shaped. The screw protrusion 14 can be machined on the surface of the screw 1, or fixed on the screw 1 by welding.

[0032] The working process of the utility model is as follows: during normal operation, the motor rotor 5 drives the lead screw 1 to rotate, so that the nut 2 moves to the right relative to the lead screw 1, and synchronously drives the piston 4 to slide to the right. Under extreme working conditions, the motor reverses, driving the nut 2 to move toward the motor rotor assembly surface 51. Due to the existence of the gap 6, the front end surface 22 of the nut 2 can be accommodated to avoid direct contact between the motor rotor assembly surface 51 and the front end surface 22, resulting in friction locking. At the same time, when the lead screw 1 rotates so that the nut protrusion 21 and the lead screw protrusion 14 contact each other, the two stop each other, the nut 2 is locked, and the motor also stops reversing.

[0033] It is understandable that, for those skilled in the art, any equivalent replacement or change to the technical solution and the concept of the utility model should fall within the protection scope of the claims attached to the utility model.

Claims

1. A ball screw unit anti-locking structure, characterized in that: The invention comprises a lead screw (1), a nut (2) and a ball (3); one end of the lead screw (1) is a motor connection end (11); the other end of the lead screw (1) is a piston connection end (12) for sleeve-mounting a piston (4); the piston (4) is fixed on the nut (2); the nut (2) is rotatably matched with the lead screw (1) through a plurality of balls (3); a motor interface matching surface (13) is provided on the motor connection end (11) for assembling a motor rotor (5); a side of the nut (2) close to the motor interface matching surface (13) is a front end surface (22); a nut protrusion (21) is provided on the front end surface (22); a lead screw protrusion (14) is formed on the outer wall of the lead screw (1) by extending radially outward; the lead screw protrusion (14) is located between the motor interface matching surface (13) and the front end surface (22); the lead screw protrusion (14) is used to match the nut protrusion (21) to block the front end surface (22).

2. The anti-locking structure of the ball screw unit according to claim 1, characterized in that: The distance D1 between the outermost edge of the screw protrusion (14) and the axis of the screw (1) is greater than the distance D2 between the innermost edge of the nut protrusion (21) and the axis of the screw (1).

3. The anti-locking structure of the ball screw unit according to claim 2, characterized in that: A gap (6) is provided between the lead screw protrusion (14) and a motor rotor assembly surface (51) on the inner wall of the motor rotor (5).

4. The ball screw unit anti-locking structure according to claim 3, characterized in that: An external thread (23) is provided on the side of the nut (2) facing away from the front end surface (22) for connecting with the piston (4).

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