Zero-position anti-rotation limit mechanism and automobile wire-controlled brake system

Abstract

A zero-position anti-rotation limit mechanism and an automobile wire-controlled brake system belong to the technical field of automobile wire-controlled brake systems, wherein the zero-position anti-rotation limit mechanism comprises a lead screw shaft connected to a rotor shaft transmission and a lead screw nut matched therewith, the lead screw nut is fixedly connected to a piston, one end of the lead screw shaft is sleeved with a nut baffle plate for anti-rotation, and the nut baffle plate is provided with a limit boss I for limiting the axial retreat of the lead screw nut in the zero position. The beneficial effect of the present invention is that the present invention can adjust the phase of the nut baffle plate and the lead screw nut during installation, can solve the problem of difficult phase matching during installation, and can avoid the situation where debris generated by interference fit leads to damage or scrapping of parts.

Description

Technical Field

[0001] The invention relates to the technical field of automobile brake-by-wire systems, and in particular to a zero-position anti-rotation limiting mechanism and an automobile brake-by-wire system. Background Art

[0002] At present, the main working principle of the wire control brake system is that the rotor shaft of the motor drives the screw shaft to rotate, and then the screw nut converts the rotational motion into linear motion, thereby driving the piston in the electric cylinder forward or backward, thereby compressing the brake fluid and building up hydraulic pressure to provide braking force for the vehicle. During the pressure building and decompression process of the electric cylinder, the screw nut needs to make reciprocating linear motion within a certain stroke. If there is no zero-position anti-rotation limit structure, the screw nut will keep retreating during the pressure relief process, contacting other components and generating friction torque. The friction torque may exceed the starting torque of the motor, making the screw nut unable to move forward, resulting in the system being unable to achieve the braking function.

[0003] In the prior art, a nut baffle is generally used, which is interference fit with the lead screw shaft, and a boss structure is provided on the nut baffle to convert the axial impact into a circumferential impact when retreating, so as to limit the axial movement of the lead screw nut. The problems existing in the zero-position anti-rotation limit mechanism using the nut baffle are:

[0004] 1. The boss structure on the nut baffle is processed by welding or turning, which is time-consuming, labor-intensive and costly. 2. When the screw nut retracts to near the zero position, if the boss structure on the screw nut is used as the reference point on the circumference, after the nut baffle is installed, the relative angle between the boss structure on the nut baffle and the boss structure on the screw nut is recorded as β. In the zero-position anti-rotation limit mechanism, when installing the boss on the screw nut baffle, the angle β is required to be within a certain accuracy range, so that when the screw nut retracts to the zero position, the two bosses can offset each other and meet the strength requirements. However, during the processing, the position of the boss on the screw nut on the circumference is random, which makes the angle β difficult to control and increases the difficulty of installation. 3. When the screw nut baffle is interference fit with the screw shaft, if the phase does not meet the requirements, it cannot be adjusted, resulting in scrapped parts. 4. When the screw nut baffle and the screw shaft are pressed together with interference fit, there is a possibility of generating debris. These debris fall into the ball screw pair, which will reduce the service life of the ball screw pair. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a zero-position anti-rotation limit mechanism, which can adjust the phase of the nut baffle and the screw nut during installation, solve the problem of difficult phase matching during installation, and avoid the situation where interference fit produces debris and causes damage or scrapping of parts.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention to solve its technical problem is: the zero-position anti-rotation limit mechanism includes a screw shaft transmission connected to the rotor shaft and a screw nut matching therewith, the screw nut is fixedly connected to the piston, one end of the screw shaft is anti-rotation sleeved with a nut baffle, one end of the screw shaft is fixedly sleeved with an elastic part and an external spline sleeve, and the nut baffle is provided with a limiting boss I for limiting the axial retreat of the screw nut in the zero position.

[0007] The nut baffle comprises a baffle body, a flanging hole is arranged at the center of the baffle body, the flanging hole is connected to the screw shaft for anti-rotation, and the flanging hole is clearance-matched with the screw shaft.

[0008] The cross-sectional shape of the flanged hole is consistent with the cross-sectional shape of the screw shaft shoulder, and is composed of a combination of graphics periodically arranged around its center, including straight-sided polygons, curved-sided polygons or mutually concave-convex structures; one end of the screw shaft cooperates with the flanged hole.

[0009] A limiting boss I is stamped on the side of the nut baffle plate facing the lead screw nut, and a limiting boss II is arranged on the lead screw nut.

[0010] A shaft shoulder is provided at one end of the lead screw shaft, and the shaft shoulder is connected to the nut baffle along the axial direction;

[0011] The distances between the centers of the limiting boss I and the limiting boss II and the central axis of the screw shaft are equal; when the screw nut is in the zero position, the limiting boss I is in contact with the limiting boss II along the rotation direction of the screw shaft.

[0012] The transmission mechanism also includes a rotation-stopping guide sleeve installed on the valve body of the online control braking system, a plurality of guide ribs are arranged on the inner wall of the rotation-stopping guide sleeve along its length direction, and a guide groove connected to the corresponding guide ribs for sliding guide is arranged on the lead screw nut.

[0013] One end of the screw shaft is interference fit with the outer spline sleeve, the outer spline sleeve is connected to the rotor shaft through the inner spline sleeve, and an elastic member is sleeved on the screw shaft between the outer spline sleeve and the nut baffle.

[0014] The elastic member is configured as an annular rubber spring pad, and the flange of the nut baffle is connected to the elastic member to prevent rotation.

[0015] A mounting hole is provided at the center of the elastic member, the mounting hole is sleeve-connected to the lead screw shaft, and the flange of the nut baffle extends into the mounting hole and cooperates with the anti-rotation clearance of the mounting hole.

[0016] A vehicle brake-by-wire system comprises the zero-position anti-rotation limiting mechanism.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention provides a zero-position anti-rotation limit mechanism, which is provided with a nut baffle plate on an anti-rotation sleeve at one end of the screw shaft, thereby preventing debris from falling into the transmission mechanism during the installation process of the nut baffle plate and the screw shaft due to interference fit, thereby damaging the life of the transmission mechanism. At the same time, when installing the nut baffle plate, the phase between the nut baffle plate and the boss on the screw nut can be adjusted, thereby avoiding the phase error caused by interference fit and causing the parts to be scrapped.

[0019] 2. In the present invention, the cross-sectional shape of the flanged hole on the nut baffle is composed of a combination of graphics periodically arranged around the center of the flanged hole. When installing the nut baffle, multi-angle adjustment can be performed to meet the phase requirement between the nut baffle and the boss on the screw nut, so that the boss on the nut baffle can be processed at any position on the circumference without processing phase requirements, which greatly reduces the difficulty of processing and installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0021] Figure 1 It is a schematic diagram of the phase angle between the lead screw nut and the boss on the nut baffle in the prior art;

[0022] Figure 2 It is a cross-sectional view of the zero-position anti-rotation limiting mechanism of the present invention;

[0023] Figure 3 It is an exploded view of the zero-position anti-rotation limiting mechanism of the present invention;

[0024] Figure 4 It is a structural schematic diagram of the relative position between the lead screw nut and the nut baffle when in the zero position in the present invention;

[0025] Figure 5 It is a structural schematic diagram of a structure in which the flanging hole and the screw shaft are connected to prevent rotation in the present invention;

[0026] Figure 6 It is a structural schematic diagram of another structure in which the flange hole is connected to the screw shaft for anti-rotation in the present invention;

[0027] The markings in the above figures are: 1. Screw shaft, 11. Shoulder, 2. Screw nut, 21. Limiting boss II, 22. Guide groove, 3. Nut baffle, 31. Baffle body, 32. Flanged edge, 33. Flanged edge hole, 34. Limiting boss I, 4. Anti-rotation guide sleeve, 41. Guide rib, 5. External spline sleeve, 6. Elastic part, 61. Mounting hole. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0029] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] like Figure 1 to Figure 4 As shown, the present invention provides a zero-position anti-rotation limit mechanism, which is a part of the automobile wire control brake system, including a stop guide sleeve 4 installed on the valve body of the wire control brake system, a screw shaft 1 connected to the rotor shaft transmission and a screw nut 2 matched therewith, wherein the rotor shaft is a hollow shaft, the stop guide sleeve 4 is arranged in the inner cavity of the rotor shaft, a plurality of guide ribs 41 are arranged on the inner wall of the stop guide sleeve 4 along its length direction, a guide groove 22 connected to the corresponding guide ribs 41 for sliding guidance is arranged on the screw nut 2, and the screw nut 2 is fixedly connected to the piston. One end of the screw shaft 1 is interference fit with the outer spline sleeve 5, and the outer spline sleeve 5 is connected to the rotor shaft through the inner spline sleeve, and the rotational motion of the rotor shaft is transmitted to the screw shaft 1 by spline transmission. The screw shaft 1 rotates to drive the screw nut 2 thereon to stably reciprocate along the axial direction of the screw shaft 1 and the axial direction of the stop guide sleeve 4, thereby driving the piston to move in the booster cylinder to achieve pressure building and pressure reduction.

[0032] A nut baffle 3 is installed on the anti-rotation sleeve of the end of the screw shaft 1 away from the piston, and a limit boss Ⅰ34 is provided on the nut baffle 3 to limit the axial retreat of the screw nut 2 in the zero position. The limit boss Ⅰ34 is stamped and formed on the side of the nut baffle 3 toward the screw nut 2, which reduces the processing steps and reduces the cost. A limit boss Ⅱ21 is provided on the screw nut 2, and the distances between the centers of the limit boss Ⅰ34 and the limit boss Ⅱ21 and the center axis of the screw shaft 1 are equal. When the screw nut 2 is in the zero position, the limit boss Ⅰ34 conflicts with the limit boss Ⅱ21 along the rotation direction of the screw shaft 1, so that the screw nut 2 can no longer retreat.

[0033] During the pressure building and pressure reducing process of the electric cylinder, since the screw nut 2 needs to perform reciprocating linear motion within a certain stroke, the screw nut 2 will keep retreating during the pressure reducing process. When the screw nut 2 retreats to the zero position, the limit boss Ⅰ34 conflicts with the limit boss Ⅱ21 along the rotation direction of the screw shaft 1, converting the axial force of the screw shaft 1 into a friction torque between the limit bosses, so that the screw nut 2 no longer retreats.

[0034] Therefore, the present invention installs a nut baffle 3 in an anti-rotation sleeve at one end of the screw shaft 1, which not only allows the nut baffle 3 to rotate synchronously with the screw shaft 1, but also prevents debris from falling into the transmission mechanism during the installation process of the nut baffle 3 and the screw shaft 1 due to interference fit, thereby damaging the life of the transmission mechanism. At the same time, when installing the nut baffle 3, the phase between the limit boss Ⅰ34 and the limit boss Ⅱ21 at the zero position can be adjusted, thereby avoiding the phase error caused by interference fit and causing the parts to be scrapped.

[0035] Specifically, the nut baffle 3 includes a baffle body 31, a through hole is arranged at the center of the baffle body 31, and an outward flange 32 is formed at the through hole to form a flange hole 33, the flange hole 33 is connected to the screw shaft 1 for anti-rotation, and the flange hole 33 and the screw shaft 1 are clearance-matched, thereby avoiding the situation in which debris may fall into the transmission mechanism during the installation process of the nut baffle 3 and the screw shaft 1 due to the interference fit, thereby damaging the life of the transmission mechanism, and also avoiding the situation in which the phase error caused by the interference fit may cause the parts to be scrapped.

[0036] The cross-sectional shape of the flanged hole 33 is consistent with the cross-sectional shape of the screw shaft 1, and is composed of a combination of graphics periodically arranged around the center of the flanged hole 33, including straight-sided polygons, curved-sided polygons or mutually concave-convex structures, such as Figure 5 and Figure 6The cross-sectional shape of one end of the screw shaft 1 matches the cross-sectional shape of the flanged hole 33, so that when the nut baffle 3 is installed, multiple angles can be adjusted, which can meet the phase accuracy requirements between the nut baffle 3 and the boss on the screw nut 2, so that the boss on the nut baffle 3 can be processed at any position on the circumference without processing phase requirements, which greatly reduces the difficulty of processing and installation.

[0037] In addition, in order to axially limit the screw shaft 1, a shoulder 11 is set at one end of the screw shaft 1, and the shoulder 11 is stopped on one side of the nut baffle 3. An elastic part 6 is sleeved on the screw shaft 1 between the external spline sleeve 5 and the nut baffle 3, and the elastic part 6 is stopped on the other side of the nut baffle 3, thereby realizing the axial limitation of the nut baffle 3.

[0038] The elastic member 6 is configured as an annular rubber spring washer, which can not only limit the nut baffle 3 axially, but also eliminate the axial installation clearance of the screw shaft.

[0039] The flange 32 of the nut baffle 3 extends into the elastic member 6 and is connected to the elastic member 6 for anti-rotation. The specific structure is as follows: a mounting hole 61 is provided at the center of the elastic member 6, and the cross-sectional shape of the mounting hole 61 is set to be polygonal or special-shaped. The mounting hole 61 is sleeved and connected with the screw shaft 1. The flange 32 of the nut baffle 3 extends into the mounting hole 61 and is matched with the anti-rotation clearance of the mounting hole 61, ensuring that the screw shaft 1 rotates while driving the external spline sleeve 5, the nut baffle 3 and the elastic member 6 to rotate synchronously, without generating abnormal noise and wear of parts due to relative rotation, thereby improving the service life of the entire transmission mechanism.

[0040] The working principle of the above-mentioned zero-position anti-rotation limit mechanism is as follows: when it is necessary to build pressure by braking, the rotor shaft of the motor rotates, and the rotational motion of the rotor shaft is transmitted to the screw shaft 1 by means of spline transmission. The screw shaft 1 rotates and drives the screw nut 2 thereon to move a specific stroke along the axial direction of the anti-rotation guide sleeve 4 stably in the direction away from the nut baffle 3, thereby driving the piston to move in the booster cylinder to achieve pressure building. When it is necessary to release and reduce pressure by braking, the rotor shaft of the motor rotates in the opposite direction, and the rotational motion of the rotor shaft is transmitted to the screw shaft 1 by means of spline transmission. The screw shaft 1 rotates and drives the screw nut 2 thereon to move along the axial direction of the anti-rotation guide sleeve 4 stably in the direction close to the nut baffle 3, thereby driving the piston to move in the booster cylinder. When the screw nut 2 retreats to the zero position, the limit boss I34 is in contact with the limit boss II21 along the rotation direction of the screw shaft 1, and the axial force of the screw shaft 1 is converted into a friction torque between the limit bosses, so that the screw nut 2 no longer retreats.

[0041] In summary, the present invention allows the phases of the nut baffle and the lead screw nut to be adjusted during installation, can solve the problem of difficult phase matching during installation, and can avoid the situation where debris generated by interference fit leads to damage or scrapping of parts.

[0042] The above description is only used to illustrate some principles of the present invention. This specification is not intended to limit the present invention to the specific structure and application scope shown and described. Therefore, all corresponding modifications and equivalents that may be used belong to the patent scope applied for by the present invention.

Claims

1. A zero-position anti-rotation limit mechanism, comprising a lead screw shaft drivingly connected to a rotor shaft and a lead screw nut matched therewith, wherein the lead screw nut is fixedly connected to a piston, and characterized in that: A nut baffle is installed on one end of the screw shaft in an anti-rotation sleeve, and a limiting boss I is provided on the nut baffle for limiting the axial retreat of the screw nut in the zero position.

2. The zero-position anti-rotation limiting mechanism according to claim 1 is characterized in that: The nut baffle comprises a baffle body, a flanging hole is arranged at the center of the baffle body, the flanging hole is connected to the screw shaft for anti-rotation, and the flanging hole is clearance-matched with the screw shaft.

3. The zero-position anti-rotation limiting mechanism according to claim 2 is characterized in that: The cross-sectional shape of the flanged hole and the cross-sectional shape of the screw shaft shoulder are composed of graphics periodically arranged around their centers, and the graphics include straight-sided polygons, curved-sided polygons or mutually concave-convex structures; one end of the screw shaft is anti-rotationally matched with the flanged hole.

4. The zero-position anti-rotation limiting mechanism according to claim 1, characterized in that: A limiting boss I is stamped on the side of the nut baffle plate facing the lead screw nut, and a limiting boss II is arranged on the lead screw nut.

5. The zero-position anti-rotation limiting mechanism according to claim 4 is characterized in that: A shaft shoulder is provided at one end of the lead screw shaft, and the shaft shoulder is connected to the nut baffle along the axial direction; The distances between the centers of the limiting boss I and the limiting boss II and the central axis of the screw shaft are equal; when the screw nut is in the zero position, the limiting boss I is in contact with the limiting boss II along the rotation direction of the screw shaft.

6. The zero-position anti-rotation limiting mechanism according to claim 1, characterized in that: The transmission mechanism also includes a rotation-stopping guide sleeve installed on the valve body of the online control braking system, a plurality of guide ribs are arranged on the inner wall of the rotation-stopping guide sleeve along its length direction, and a guide groove connected to the corresponding guide ribs for sliding guide is arranged on the lead screw nut.

7. The zero-position anti-rotation limiting mechanism according to claim 2, characterized in that: One end of the screw shaft is interference fit with the outer spline sleeve, the outer spline sleeve is connected to the rotor shaft through the inner spline sleeve, and an elastic member is sleeved on the screw shaft between the outer spline sleeve and the nut baffle.

8. The zero-position anti-rotation limiting mechanism according to claim 7, characterized in that: The elastic member is configured as an annular rubber spring pad, and the flange of the nut baffle is connected to the elastic member to prevent rotation.

9. The zero-position anti-rotation limiting mechanism according to claim 8, characterized in that: A mounting hole is provided at the center of the elastic member, the mounting hole is sleeve-connected to the lead screw shaft, and the flange of the nut baffle extends into the mounting hole and cooperates with the anti-rotation clearance of the mounting hole.

10. A vehicle brake-by-wire system, characterized in that: It comprises a zero-position anti-rotation limit mechanism as described in any one of claims 1 to 9.

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