CN212407397U - Brake-by-wire actuator for vehicle - Google Patents

Abstract

The utility model discloses a drive-by-wire brake actuating device for vehicle, including executor and screw drive mechanism, screw drive mechanism includes lead screw, nut, roller and holder, forms the spiral space between the external screw thread of lead screw and the internal thread of nut, and the roller sets up on the holder, and holder and roller are located the spiral space. The utility model discloses a drive-by-wire brake actuating device for vehicle, through the combination of adding holder and roller between screw drive's lead screw and nut, rolling motion is done to a plurality of rollers when screw drive moves, and the structure easily realizes, and the production is little with the assembly degree of difficulty, and is with low costs, and the holder makes the roll that the roller can be regular, guarantees that screw drive moves in-process can continuous operation, can avoid appearing the dead condition of inefficacy of card to can satisfy the requirement that provides big braking thrust.

Description

Brake-by-wire actuator for vehicle

Technical Field

The utility model belongs to the technical field of vehicle braking system, specifically speaking, the utility model relates to a drive-by-wire braking executive device for vehicle.

Background

The brake-by-wire technology improves the automation degree of the vehicle, improves the running safety of the vehicle, is dependent on hybrid or pure electric vehicle types, and gradually becomes the development trend of the automobile industry. Electric boosters (eboosters), Electrohydraulic Brake Systems (EHBs) and Electromechanical Brake Systems (EMBs) are the predominant forms of brake-by-wire technology today.

The executing device is a difficult point of a brake-by-wire technology, power provided by a motor is generally transmitted to a lead screw transmission mechanism through a speed reducing and torque increasing mechanism, rotary motion is converted into linear motion of a connecting piece through the lead screw transmission mechanism, and the connecting piece generates thrust to a brake pad and a brake disc, so that braking force is obtained. The brake-by-wire actuator needs to satisfy the following characteristics:

1. the reaction time is short: the reaction time here is the time from the receipt of the command by the brake system to the maximum braking force. The shorter the reaction time is, the shorter the braking distance is;

2. the thrust is large: under the condition that the road adhesion coefficient is satisfied, the larger the thrust of the braking device is, the larger the achievable deceleration is;

the brake-by-wire actuating device needs to meet the requirements of short reaction time and high thrust at the same time, and is equal to the requirement of meeting the requirement of high output power. In the widely used existing vehicle battery technology, the voltage is generally 12V-14V, which is influenced by a low-voltage power supply, and the limit power of the motor is limited, resulting in a smaller motor power. The smaller input power and the larger output power necessarily require the high transmission efficiency of the entire transmission mechanism. The transmission mechanism at least comprises a lead screw transmission mechanism, the lead screw transmission mechanism is used as a motion conversion mechanism, the transmission efficiency and the bearing capacity of the lead screw transmission mechanism directly influence the overall performance of the executing device, and the lead screw transmission mechanism becomes the key point for solving the problem.

Screw drive mechanisms that can satisfy high transmission efficiency in the prior art have "ball screw drive mechanism" and "planet roller screw drive mechanism", but these two kinds of screw drive mechanisms all have following not enough:

1. the ball screw transmission mechanism has insufficient bearing capacity: the ball screw mechanism mainly comprises a screw, a nut and balls, and the basic principle is that the balls are arranged in a spiral space formed by the screw and the nut, and the screw and the nut are driven by a plurality of rolling balls. The ball screw has the characteristics of small friction force and high transmission efficiency, but has the problem that the ball for transmitting power is in point contact with the screw or the nut, so that the ball screw has high contact stress, and the bearing capacity of the ball screw is insufficient. The problem is very serious for the EMB, the ball screw transmission mechanism in the prior art can only meet the braking of a rear wheel, and for a front wheel with larger braking force demand, the ball screw transmission mechanism can not meet the EMB requirement;

2. although the planetary roller screw transmission mechanism can meet the functional requirements, the cost is too high, and the industrialization is difficult: patent document CN108583543A proposes a brake-by-wire actuator using a planetary roller screw, which has higher load-bearing capacity and can provide larger thrust than a ball screw. However, the patent publication No. CN108583543A does not consider the cost problem of the planetary roller screw transmission mechanism, and the planetary roller screw transmission mechanism has high requirements on the size and geometric tolerance of the components; in addition, interference is easily generated between parts of the transmission mechanism which are mutually matched in principle, so that the processing requirement and the integral assembly requirement are very high, the production and the manufacture are very precise, the cost of the planetary roller screw and the applied brake device is very high, and the popularization and the application in the automobile industry are difficult.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides a drive-by-wire brake actuating device for vehicle, when the purpose is reduce cost, satisfies the requirement that provides big braking thrust.

In order to realize the purpose, the utility model discloses the technical scheme who takes does: the brake-by-wire executing device for the vehicle comprises an actuator and a lead screw transmission mechanism which is connected with the actuator and is used for converting rotary motion from the actuator into linear motion for driving a functional part to move forwards, wherein the lead screw transmission mechanism comprises a lead screw, a nut, a roller and a retainer, a spiral space is formed between an external thread of the lead screw and an internal thread of the nut, the roller is arranged on the retainer, and the retainer and the roller are positioned in the spiral space.

The roller is a cylindrical roller or a tapered roller.

The cage is configured to control the angle of inclination of the rollers during movement to be within a set range.

The retainer is provided with an accommodating cavity for accommodating the roller, and the roller can freely rotate in the retainer.

The thickness of the retainer is smaller than the minimum diameter of the roller, and the outer circular surface of the roller is in contact with the thread surface of the screw rod and/or the nut.

The retainer is provided with a first avoidance hole and a second avoidance hole, the accommodating cavity is positioned between the first avoidance hole and the second avoidance hole, and the inner side surface of the accommodating cavity is in clearance contact with the side surface and two end surfaces of the roller; the first avoidance hole and the second avoidance hole are at least provided with a group of bosses, the bosses are used for preventing the rollers from being separated from the containing cavities, and the rollers respectively penetrate through the first avoidance hole and the second avoidance hole and are in contact with the screw rod and the nut.

The rollers are arranged in a plurality of numbers, all the rollers are sequentially arranged in the spiral space along the spiral direction, and the cross section of the spiral space is rectangular or trapezoidal.

The retainer is made of elastic steel materials.

The screw rod transmission mechanism further comprises a first limiting part, a second limiting part, a first elastic part and a second elastic part, wherein the first limiting part, the second limiting part, the first elastic part and the second elastic part are arranged in the spiral space, the retainer is located between the first elastic part and the second elastic part, the first elastic part is located between the retainer and the first limiting part, and the second elastic part is located between the retainer and the second limiting part.

The first elastic piece and the second elastic piece are both helical springs, and the side surfaces of the enveloping bodies of the first elastic piece and the second elastic piece are matched with the shapes of helical spaces.

The utility model discloses a drive-by-wire brake actuating device for vehicle, through the combination of adding holder and roller between screw drive's lead screw and nut, rolling motion is done to a plurality of rollers when screw drive moves, and the structure easily realizes, and the production is little with the assembly degree of difficulty, and is with low costs, and the holder makes the roll that the roller can be regular, guarantees that screw drive moves in-process can continuous operation, can avoid appearing the dead condition of inefficacy of card to can satisfy the requirement that provides big braking thrust.

Drawings

The description includes the following figures, the contents shown are respectively:

FIG. 1 is a schematic view of the construction of a brake;

FIG. 2 is a cross-sectional view of the lead screw drive;

FIG. 3 is an exploded view of the retainer, roller, elastic member and limiting member of the screw transmission mechanism;

FIG. 4 is a schematic view of the cage, roller deployment of the lead screw drive;

labeled as: 1. a lead screw; 2. a nut; 3. a roller; 4. a holder; 5. a first elastic member; 6. a first limit piece; 7. a second elastic member; 8. a second limiting member; 9. a brake caliper support; 10. braking the inner plate; 11. a brake disc; 12. a brake outer plate; 13. an actuator; 14. a brake caliper body.

Detailed Description

The following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings, for the purpose of helping those skilled in the art to understand more completely, accurately and deeply the conception and technical solution of the present invention, and to facilitate its implementation.

As shown in fig. 1 to 3, the present invention provides a brake-by-wire actuator for a vehicle, which includes an actuator 13 and a lead screw transmission mechanism connected to the actuator 13 and used for converting a rotary motion from the actuator 13 into a linear motion for driving a functional member of the brake device to advance. When the functional element of the braking device advances, the inner braking sheet 10 of the braking device can be pushed to move, so that the inner braking sheet 10 and the outer braking sheet 12 clamp the braking disc 11, and braking force is generated, thereby realizing braking of the wheel. The screw transmission mechanism comprises a screw 1, a nut 2, a roller 3 and a retainer 4, a spiral space is formed between the external thread of the screw 1 and the internal thread of the nut 2, the roller 3 is arranged on the retainer 4, the retainer 4 and the roller 3 are positioned in the spiral space, and the screw 1 and the nut 2 complete relative movement through rolling of the rollers 3 on the thread surface.

To ball and the not enough in the online control action actuating device of planet roller screw, the utility model discloses carry out the analysis to current drive-by-wire braking actuating device's motion: when the executing device operates, the screw rod mechanism is generally required to do reciprocating motion, and the moving range of the nut is limited, so that the requirement can be met by adopting a non-circulating screw rod.

The stress characteristic of the functional part is that the thrust can be increased from 0 to a required value and then reduced to 0, at the moment, the stress is 0, and then the thrust changes continuously and repeatedly; meanwhile, the stress direction is unidirectional, the stress is gradually reduced in the opposite direction, and the requirement on the bearing capacity is not high.

The transmission efficiency of the screw transmission mechanism adopted in the utility model is consistent with that of the ball screw, but the bearing capacity is improved; the lead screw transmission mechanism with the structure adopts the cylindrical or tapered rollers to replace the balls, but the working principle of the lead screw and the nut still rolls, the transmission efficiency is basically consistent with that of the ball screw, and the lead screw transmission mechanism is still obviously improved compared with the common lead screw. Moreover, the lead screw transmission mechanism and the ball screw transmission mechanism in the prior art are both suitable for Hertz's law. Ball among the prior art bears through the spheroid between lead screw and the nut, is the point contact between spheroid and the flank of thread, the utility model discloses in, bear through cylinder or tapered roller between lead screw and the nut, be line contact between roller and the flank of thread, according to the hertz formula, line contact's ball bearing capacity is higher.

The utility model discloses the roll of roller rule can be realized to the screw drive who adopts in. In a tapered roller screw pair proposed in patent publication No. CN108561523A, reversing devices are provided at both ends of a nut, a circulation passage is formed between a screw and the nut, and a plurality of tapered rollers are arranged in the passage to form a circulation chain. In order to meet the requirement of circular motion, the structure of the nut is complex, and two ends of the nut need to be provided with reversing devices, so that the processing and assembling difficulty is increased; a plurality of tapered rollers are arranged in the channel, and the closer the rollers are to the axis of the screw rod, the smaller the linear velocity is, and the inclination of the rollers during movement can be caused by the difference of the linear velocity. Although the inconsistency of the linear velocity can be compensated by the inconsistency of the diameters of the tapered rollers, problems such as eccentricity of the screw cannot be avoided due to manufacturing variations, and the rollers are still prone to tilt during rolling. The inclination of the roller can cause the actual rolling direction of the roller to deviate in the designed movement direction, and when the deviation angle is too large, the circulation chain can be blocked, and further the transmission fails.

The utility model discloses in the screw drive who adopts, a plurality of rollers are spacing on the heliciform holder, and during the mechanism function, the holder moves together with the roller, and the roller can not take place excessive slope under the restriction of holder to realize the roll of roller rule, eliminated this structure and taken place the dead possibility of card.

The utility model discloses well screw drive who adopts constructs simple structure, and manufacturing cost reduces: in the prior art, a lead screw transmission mechanism is usually designed to be a circulating structure, but in an executing device, a lead screw or a nut generally does reciprocating motion when doing relative motion, and the relative motion range is limited; and the stress characteristic of the screw structure is that the positive pressure can be increased from 0 to a required value and then reduced to 0, and the screw structure reciprocates continuously, when the positive pressure is 0, the roller can be returned to the initial position through the return device, and the next working cycle is prepared, and the requirement of mechanical transmission can be met, so that the screw structure is not necessary to be designed into a circulating structure with a complex structure.

Specifically, as shown in fig. 1 to 3, the nut 2 is sleeved on the screw rod 1, an external thread is provided on the screw rod 1, an internal thread is provided inside the nut 2, and the screw space is a cavity formed between the external thread of the screw rod 1 and the internal thread of the nut 2 with a certain lead. The retainer 4 in the spiral space is in a spiral structure, the lead of the retainer 4 is consistent with the lead of the screw rod 1 or the nut 2, the retainer 4 extends in the spiral direction in the spiral space, the rollers 3 are installed in the spiral space together with the retainer 4, the retainer 4 is used for limiting the rollers 3 in the spiral space, and the rollers 3 in the retainer 4 can freely rotate around the axis of the rollers.

The retainer 4 is constructed to be used for controlling the inclination angle of the roller 3 in the movement process (the inclination angle is the included angle between the axis of the roller 3 and the width direction of the retainer 4) to be within a set range, the set range of the inclination angle is 0-5 degrees, so that the roller 3 is prevented from excessively inclining in the operation process of the lead screw transmission mechanism, the actual movement direction of the lead screw transmission mechanism and the movement direction of theoretical design can not generate larger deviation, the continuous operation of the lead screw transmission mechanism in the operation process is ensured, the condition of failure due to the locking of a circulating chain can not occur, the structure of the lead screw transmission mechanism is similar to an acyclic ball screw, the structure is simpler, the difficulty from manufacturing and processing to assembling is small, the cost is low, and the structure is easier to realize.

The closer the roller 3 is to the axis of the screw 1, the smaller the linear velocity is, which leads to inconsistent speeds at the two axial ends of the roller 3 and easy inclination, therefore, the retainer 4 is arranged, and the retainer 4 has the function of ensuring that the inclination angle of the roller 3 is in a reasonable range, so that the actual movement direction of the roller 3 and the designed movement direction can not have larger deviation.

The roller 3 can be a cylindrical roller or a tapered roller, the cylindrical roller is of a cylindrical structure with a constant diameter, and the tapered roller is of a conical structure. For line contact between the outer disc of roller 3 and the helicoid of lead screw 1 and the helicoid of nut 2, for the point atress contact of the spherical ball that adopts among the prior art, the advantage of adopting cylindrical roller or tapered roller is through the contact line support load, consequently for prior art's ball screw drive mechanism, the utility model discloses the bearing capacity of the lead screw drive mechanism who adopts has obtained the improvement to the bearing capacity of brake-by-wire final controlling element has been improved, makes brake-by-wire final controlling element's bearing capacity can satisfy vehicle front wheel EMB's requirement. Moreover, the combination of the retainer 4 and the rollers 3 is added between the screw rod 1 and the nut 2, and the plurality of rollers 3 do rolling motion when the screw rod transmission mechanism operates, so that the transmission efficiency can be improved.

As shown in fig. 1 to 3, the cage 4 has a housing chamber for housing the roller 3, and the cage 4 houses both end faces and side faces of the roller 3, so that the roller 3 does not fall off in a free state, and the roller 3 can freely rotate in the cage 4. The thickness of the retainer 4 is smaller than the minimum diameter of the roller 3, the outer circular surfaces of the roller 3 protrude toward the opposite sides in the thickness direction of the retainer 4, and the outer circular surfaces of the roller 3 are in contact with the thread surfaces of the screw 1 and/or the nut 2.

As shown in fig. 1 to 3, the retainer 4 has a first avoiding hole and a second avoiding hole, the accommodating cavity is located between the first avoiding hole and the second avoiding hole, and the roller 3 respectively passes through the first avoiding hole and the second avoiding hole to contact with the screw rod 1 and the nut 2. The first avoidance hole is a hole formed in the first outer wall surface of the retainer 4, the second avoidance hole is a hole formed in the second outer wall surface of the retainer 4, the first outer wall surface and the second outer wall surface are two outer wall surfaces opposite to each other in the thickness direction of the retainer 4, the thickness direction of the retainer 4 is perpendicular to the threaded surface of the screw rod 1, and the width directions of the first avoidance hole and the second avoidance hole are perpendicular to the axis of the roller 3 and perpendicular to the thickness direction of the retainer 4. A group of bosses are arranged on the first outer wall surface and positioned at two sides of the first avoidance hole, two groups of bosses are arranged on the second outer wall surface and positioned at two sides of the second avoidance hole, the distance between the bosses on the first outer wall surface and positioned at two opposite sides of the first avoidance hole is smaller than the diameter of the roller 3 or the width of the accommodating cavity, the distance between the bosses on the second outer wall surface and positioned at two opposite sides of the second avoidance hole is also smaller than the diameter of the roller 3 or the width of the accommodating cavity, the first avoidance hole and the second avoidance hole are communicated with the accommodating cavity, the width of the accommodating cavity is approximately equal to the diameter of the roller 3, the length of the accommodating cavity is approximately equal to that of the roller 3, the inner side surface of the accommodating cavity is in clearance contact with the two end surfaces and the side surface of the roller, the roller 3 is located between the two opposite inner wall surfaces in the length direction of the accommodating cavity, and the roller 3 can freely rotate in the accommodating cavity. The roller 3 is kept in the accommodating cavity of the holder 4 and cannot fall off under the limit of the bosses on the two opposite sides of the first avoidance hole and the second avoidance hole.

As shown in fig. 1 to 3, the rollers 3 are provided in plural, and all the rollers 3 are arranged in sequence in a spiral direction in a spiral space whose cross-sectional shape matches the shape of the rollers 3, and the spiral space can be changed by changing the thread form or the thread form angle of the thread. When the roller 3 is a cylindrical roller, the section of the spiral space is rectangular; when the roller 3 is a tapered roller, the cross section of the spiral space is trapezoidal.

As shown in fig. 1 to 3, the screw transmission mechanism further includes a first limiting member 6, a second limiting member 8, a first elastic member 5 and a second elastic member 7 disposed in the spiral space, the holder 4 is located between the first elastic member 5 and the second elastic member 7, the first elastic member 5 is located between the holder 4 and the first limiting member 6, and the second elastic member 7 is located between the holder 4 and the second limiting member 8. One end of the first elastic part 5 is connected with the first limiting part 6, the other end of the first elastic part 5 is connected with one end of the retainer 4, one end of the second elastic part 7 is connected with the second limiting part 8, the other end of the second elastic part 7 is connected with the other end of the retainer 4, the first elastic part 5 and the second elastic part 7 in the spiral space are of spiral structures, and the first elastic part 5 and the second elastic part 7 extend in the spiral space along the spiral direction. The first elastic member 5 applies an elastic force to the holder 4 to move the holder away from the first stopper pin, the second elastic member 7 applies an elastic force to the holder 4 to move the holder away from the second stopper pin, and the first elastic member 5 and the second elastic member 7 are used for pushing the holder 4 to reset.

In the operation process of the screw transmission mechanism, after a working cycle, the roller 3 is not extruded by the screw 1 and the nut 2, the combined part formed by the retainer 4 and the roller 3 is in a free state, then under the action of the first elastic part 5 or the second elastic part 7, the retainer 4 can return to the initial position and drive the roller 3 to synchronously return to the initial position, and the next working cycle is prepared. The non-circulating type screw transmission mechanism can meet the transmission requirement of a brake-by-wire actuating device, is simpler in structure and low in size requirement on parts compared with a circulating type ball screw structure or a planetary roller screw, and is easy to realize by utilizing the prior art, so that the production and manufacturing cost is reduced.

As shown in fig. 1 to 3, side surfaces of two axial ends of the nut 2 are respectively provided with a through hole, the first limiting member 6 passes through the through hole formed on the side surface of one end of the nut 2 and extends into the thread groove of the screw rod 1, the second limiting member 8 passes through the through hole formed on the side surface of the other end of the nut 2 and extends into the thread groove of the screw rod 1, and the retainer 4, the roller 3, the first elastic member 5 and the second elastic member 7 move between the first limiting member 6 and the second limiting member 8 in the spiral space. The first limiting piece 6 and the second limiting piece 8 are fixedly arranged on the nut 2, the normal movement of the screw rod 1 and the nut 2 cannot be influenced after the first limiting piece 6 and the second limiting piece 8 are inserted into the thread groove of the screw rod 1, and the retainer 4 with the rollers 3 and the first elastic piece 5 and the second elastic piece 7 are limited to move in a space formed by the first limiting piece 6 and the second limiting piece 8, the screw rod 1 and the nut 2.

As shown in fig. 2 and 3, the first elastic member 5 and the second elastic member 7 are preferably coil springs, and the side surfaces of the envelopes of the first elastic member 5 and the second elastic member 7 are matched with the shape of the spiral space.

In order to meet the strength of the screw rod 1 or the nut 2, the screw rod 1 and the nut 2 are preferably made of alloy steel or carbon steel. The thread profile of the screw rod or the nut can be selected to be triangular, trapezoidal or rectangular, and the profile angle can be changed according to requirements.

The retainer 4 is made of a metal material, the retainer 4 is preferably made of an elastic steel material, the retainer 4 has elastic performance, and the retainer 4 can generate a certain elastic deformation amount to ensure that the retainer 4 can restore to an original state after being stressed and deformed.

The first limiting member 6 and the second limiting member 8 are made of metal materials, and the first limiting member 6 and the second limiting member 8 are preferably made of materials.

As shown in fig. 1 and 2, the screw space is formed by the first and second thread surfaces of the screw shaft 1 and the first and second thread surfaces of the nut 2, the first and second thread surfaces of the screw shaft 1 are surfaces located on both sides of the profile of the external thread of the screw shaft 1 (the included angle between the first and second thread surfaces of the screw shaft 1 is a profile angle), and the roller 3 and the retainer 4 are located between the first and second thread surfaces of the screw shaft 1. The first thread surface and the second thread surface of the nut 2 are surfaces located on both sides of a profile of the internal thread of the nut 2 (an included angle between the first thread surface and the second thread surface of the nut 2 is a profile angle), and the rollers 3 and the retainer 4 are located between the first thread surface and the second thread surface of the nut 2. The first thread surface of the screw rod 1 and the first thread surface of the nut 2 are oppositely arranged, the second thread surface of the screw rod 1 and the second thread surface of the nut 2 are oppositely arranged, the second thread surface of the screw rod 1 is parallel to the second thread surface of the nut 2, the axis of the roller 3 is perpendicular to the second thread surfaces of the screw rod 1 and the nut 2, the first thread surface of the screw rod 1 and the first thread surface of the nut 2 are positioned on two opposite sides of the retainer 4 in the thickness direction, the second thread surface of the screw rod 1 and the second thread surface of the nut 2 are positioned on two opposite sides of the retainer 4 in the width direction, and the width direction of the retainer 4 is perpendicular to the thickness direction of the retainer 4.

As shown in fig. 1 and 2, in the present embodiment, the rollers 3 are cylindrical rollers, the outer circumferential surfaces of the rollers 3 are in contact with the first thread surfaces of the screw 1 and the nut 2 and form a line contact, the cross-sectional shape of the spiral space is rectangular, and the screw 1 and the nut 2 perform a relative movement by rolling of the plurality of rollers 3 on the first thread surfaces of the screw 1 and the nut 2. Opposite outer wall surfaces in the width direction of the retainer 4 are in contact with a second thread surface of the screw 1 and a second thread surface of the nut 2, respectively.

As shown in fig. 1 and 2, in the present embodiment, the combination of the cage 4 and the rollers 3 is arranged at the lower end of the screw male thread and the upper end of the nut 2 female thread, which are in direct contact with the lower end of the nut 2 female thread.

The working angle alpha is illustrated in fig. 2 as 45 degrees, but the working angle can be varied as desired, and the working angle can be designed to be 0 at the minimum, when the thread becomes a rectangular thread.

As shown in fig. 1 and 2, in the operation of the screw transmission mechanism, the screw 1 serves as a power input component, the nut 2 serves as a power output component, and the screw 1 rotates around the axis thereof.

The actuator 13 comprises a motor, the end part of the screw rod 1 is connected with the power output end of the actuator 13, the nut 2 is connected with the functional piece, the functional piece is movably arranged, the moving direction of the functional piece is parallel to the axis of the screw rod 1, and the functional piece receives the axial thrust exerted by the nut 2. Therefore, the rotational motion from the actuator 13 is converted into the linear motion of the functional element by the screw transmission mechanism, and the functional element generates thrust to the brake inner 10 and the brake disc 11 of the brake apparatus, thereby obtaining braking force.

The brake device comprises a brake caliper body 14, and a brake inner plate 10 and a brake outer plate 12 which are arranged on the brake caliper body 14, wherein the brake inner plate 10 and the brake outer plate 12 are respectively arranged at two opposite sides of a brake disc 11, the brake disc 11 is arranged on a wheel of a vehicle, and a functional element is movably arranged inside the brake caliper body 14. When the functional element advances, the brake inner plate 10 can be pushed to move, so that the brake inner plate 10 and the brake outer plate 12 clamp the brake disc 11, and braking force is generated to realize braking.

The working principle of the screw transmission mechanism is as follows:

after the actuator 13 is operated, in the process that the screw transmission mechanism converts the rotary motion from the actuator 13 into the linear motion, the screw 1 rotates along the first direction, all the rollers 3 fixed on the retainer 4 roll on the thread surfaces of the screw 1 and the nut 2, an assembly formed by the retainer 4 and the rollers 3 moves towards one end of a spiral space in the spiral space, the first elastic part 5 or the second elastic part 7 is extruded, the rollers 3 share the load transmitted from the screw 1 and transmit the power to the nut 2 through a contact line, and as the nut 2 is limited in the radial direction and the circumferential direction, the nut 2 can be converted into the linear motion along with the rotation angle of the screw 1 according to the corresponding lead, and finally the functional part can be pushed to do the linear motion to drive the functional part to move forwards.

After the motion conversion is finished, the screw rod 1 rotates along the second direction, when the external pressure of the screw rod transmission mechanism is not eliminated, the roller 3 is extruded by the screw rod 1 and the nut 2, and at the moment, the relative motion of the screw rod 1 and the nut 2 is generated by the rolling of the roller 3; after the external pressure of the screw transmission mechanism disappears, the rollers 3 disappear under the extrusion force of the screw 1 and the nut 2, at the moment, the second thread surface of the screw 1 is contacted with the second thread surface of the nut 2, and the screw 1 is directly contacted with the thread surfaces of the nut 2 to slide to complete relative motion, so that the screw transmission mechanism can be regarded as a common screw and nut transmission mechanism, and the transmission efficiency is obviously reduced. However, in this case, the screw rod 1 is only used for single-side stress, the screw rod 1 rotates reversely to be in a non-working state, and the loaded pressure load is little or almost nonexistent, so that even if the efficiency is reduced, much energy is not consumed.

The first direction and the second direction are opposite directions, and if the first direction is clockwise, the second direction is counterclockwise. Therefore, the roller 3 is used to transmit a load between the screw 1 and the nut 2 when the screw 1 rotates in the first direction, and to convert the rotational motion into the linear motion in the screw transmission mechanism. When the screw rod 1 rotates along the second direction, the screw rod transmission mechanism realizes conversion from rotary motion to linear motion through sliding friction between the screw rod 1 and the thread surface of the nut 2.

When the plurality of rollers 3 roll in the working process of the screw transmission mechanism, the screw 1 and the nut 2 generate relative motion, the positive pressure is increased from 0 to a required value, and an assembly formed by the retainer 4 and the rollers 3 moves to one side in a spiral space; when the positive pressure is reduced to 0 from the required value, the roller 3 is not extruded by the screw rod 1 and the nut 2, the assembly is in a free state and returns to the initial position under the action of the elastic element, so that one working cycle is completed and the next working cycle is ready.

The utility model discloses a drive-by-wire braking actuating device has following characteristics:

1. the transmission efficiency is consistent with the scheme of the ball screw mechanism, but the bearing capacity can meet the requirements of the front wheel EMB: the screw transmission mechanism adopted in the utility model adopts the cylindrical or tapered roller to replace the ball, the working principle is still rolling, and the efficiency is consistent with that of the ball screw; the point corresponding to the ball is stressed and contacted, and the cylindrical or tapered roller supports the load through the contact line when moving, so that the bearing capacity of the braking device is improved;

2. for planet roller screw mechanism's scheme, the utility model discloses well screw drive mechanism structure of adopting is comparatively simple, and the degree of difficulty from manufacturing to the assembly is little, and is with low costs, the facilitate promotion: the structure of the planetary roller screw has high requirements on the size and geometric tolerance of parts; in addition, interference is easily generated between parts which are matched with each other in principle, so that the processing requirement and the integral assembly requirement are high, the production and the manufacture are very precise, the cost of the planetary roller screw and the applied brake device is high, and the popularization and the application of the planetary roller screw and the applied brake device in the automobile industry are difficult. And the utility model discloses in the screw drive mechanism who adopts, structure and non-circulating ball structure are unanimous, simple structure, and the dimensional requirement to the spare part is low, and the manufacturing degree of difficulty is little, and is with low costs to promote easily.

Examples

The brake device is of various types, and as shown in fig. 1, in the present embodiment, an electric caliper assembly is described as an example, and the electric caliper assembly includes an actuator 13, a caliper assembly, and a screw transmission mechanism. The actuator 13 comprises a motor and a speed reducing mechanism, the actuator 13 is an integration of the speed reducing mechanism and the motor for reducing speed and increasing torque, the speed reducing mechanism is connected with the motor and the screw rod transmission mechanism, the power input end of the speed reducing mechanism is connected with the motor, and the power output end of the speed reducing mechanism is connected with the screw rod 1. When braking or releasing, the rotary motion of the motor is transmitted to the lead screw transmission mechanism through the speed reducing mechanism. The structure of the actuator 13 is well known to those skilled in the art and will not be described herein.

The brake caliper assembly mainly comprises a brake caliper body 14, and a brake inner plate 10 and a brake outer plate 12 which are arranged on the brake caliper body 14, wherein the brake inner plate 10 and the brake outer plate 12 are respectively arranged at two opposite sides of a brake disc 11, the brake disc 11 is arranged on a wheel of a vehicle, and a functional element is movably arranged inside the brake caliper body 14. When the functional element advances, the brake inner plate 10 can be pushed to move, so that the brake inner plate 10 and the brake outer plate 12 clamp the brake disc 11, and braking force is generated to realize braking. The actuator 13 is provided on the caliper body 14.

The screw transmission mechanism is connected with a functional part arranged on the outer side through a nut 2, the functional part and the screw transmission mechanism are installed in a cavity of a brake caliper body 14 together, one end, far away from an actuator 13, of the functional part is in contact with a brake inner plate 10, the screw 1 is movably connected with the brake caliper body 14 through a thrust bearing, the bearing is used for limiting axial movement of the screw 1, rotary motion of a motor is transmitted to the screw 1 through a speed reducing mechanism to enable the screw 1 to rotate, the rotary motion is converted into linear motion of the functional part through the screw transmission mechanism, the functional part is pushed to the direction of the brake inner plate 10 in the axial direction through the nut 2, and the brake inner plate 10 and a brake outer plate 12 clamp a brake disc 11 to obtain braking force.

In the present embodiment, the lead screw transmission mechanism is arranged on one side, that is, the roller 3, the retainer 4, the first elastic member 5, and the second elastic member 7 of the lead screw transmission mechanism are arranged on one of two sides of the thread, which can also be regarded as a scheme that the lead screw transmission mechanism of the present embodiment is used for a unidirectional force transmission structure.

The braking force generation process of the electric brake caliper assembly is as follows: the actuator 13 is operated, the rotational motion of the motor is transmitted to the screw transmission mechanism, the screw 1 is rotated in the first direction, the roller 3 rolls in the spiral space formed between the screw 1 and the nut 2, the assembly formed by the cage 4 and the roller 3 is moved toward one end of the spiral space, and the first elastic member 5 is compressed. The roller 3 shares the load transmitted from the screw 1 and transmits the power to the nut 2 through a plurality of contact lines, the nut 2 drives the functional member to advance, and the thrust of the functional member increases from 0 to a required value. Because the nut is limited in the radial direction and the circumferential direction, the nut 2 can be converted into linear motion along with the rotation angle of the lead screw 1 according to the corresponding lead, the functional part connected with the nut is pushed to do axial linear motion, the brake inner plate 10 is further pushed, and the brake inner plate 10 and the brake outer plate 12 clamp the brake disc 11 to obtain braking force.

The braking force releasing process of the electric brake caliper assembly is as follows: when the screw rod 1 rotates along the second direction and the braking force is not eliminated, the roller 3 is still extruded by the screw rod 1 and the nut 2, and the relative motion of the screw rod 1 and the nut 2 is generated by the rolling of the roller 3; after the braking force disappears, the roller 3 is subjected to extrusion force of the screw rod 1 and the nut 2 to disappear, at the moment, the second thread surface of the screw rod 1 is in contact with the second thread surface of the nut 2, the screw rod 1 is in direct contact with the thread surfaces of the nut 2 to slide to complete relative movement, at the moment, the screw rod transmission mechanism can be regarded as a common screw rod nut transmission mechanism, and the transmission efficiency is remarkably reduced. At the moment, the thrust of the functional part is reduced to 0 from the required value, the roller 3 is not extruded by the screw rod 1 and the nut 2 any more, the combination of the retainer and the roller is in a free state and returns to the initial position under the action of the first elastic part, so that one working cycle is completed and the next working cycle is ready.

If the screw rod continues to rotate along the second direction, the state is a non-braking state, and the loaded pressure load is small, so that even if the efficiency is reduced, much energy is not consumed; and the transmission mode of the screw transmission mechanism is changed from rolling to sliding, and the phase change of the transmission mode can help the electric control device to judge whether the brake device is returned to the position or not and whether the vehicle has braking force or not.

The first direction and the second direction are opposite directions, and if the first direction is clockwise, the second direction is counterclockwise. Therefore, the roller 3 is used to transmit a load between the screw 1 and the nut 2 when the screw 1 rotates in the first direction, and to convert the rotational motion into the linear motion in the screw transmission mechanism. When the screw rod 1 rotates along the second direction, the screw rod transmission mechanism realizes conversion from rotary motion to linear motion through sliding friction between the screw rod 1 and the thread surface of the nut 2.

In summary, the braking device of the embodiment adopts a roller screw transmission mechanism, the screw and the nut transmit load through a plurality of cylindrical or tapered rollers, the contact mode is changed from point contact to line contact, and the braking device can bear larger load relative to the braking device applying the ball screw; compared with a braking device using a planetary roller screw, the screw transmission mechanism is simple in structure, and production and manufacturing cost and assembly difficulty are reduced; when braking is generated, the lead screw transmission mechanism is used as a cylindrical or tapered roller lead screw mechanism, so that the bearing capacity is improved, and when the braking is released, the phase change of the transmission mode can judge whether braking force exists in the system or not and whether the functional part returns to the position or not.

The invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above-described manner. Various insubstantial improvements are made by adopting the method conception and the technical proposal of the utility model; or without improvement, the above conception and technical solution of the present invention can be directly applied to other occasions, all within the protection scope of the present invention.

Claims (10)

1. A brake-by-wire final controlling element for vehicle is connected and is used for changing the rotary motion from the executor into the linear motion that the drive function piece gos forward including the executor with the executor, and screw drive includes lead screw, nut and roller, forms spiral space between the external screw thread of lead screw and the internal thread of nut, its characterized in that: the screw rod transmission mechanism further comprises a retainer, the roller is arranged on the retainer, and the retainer and the roller are located in the spiral space.

2. The brake-by-wire brake actuation device for a vehicle according to claim 1, characterized in that: the roller is a cylindrical roller or a tapered roller.

3. The brake-by-wire brake actuation apparatus for a vehicle according to claim 1 or 2, characterized in that: the cage is configured to control the angle of inclination of the rollers during movement to be within a set range.

4. The brake-by-wire brake actuation device for a vehicle according to claim 3, characterized in that: the retainer is provided with an accommodating cavity for accommodating the roller, and the roller can freely rotate in the retainer.

5. The brake-by-wire brake actuation device for a vehicle according to claim 4, characterized in that: the thickness of the retainer is smaller than the minimum diameter of the roller, and the outer circular surface of the roller is in contact with the thread surface of the screw rod and/or the nut.

6. The brake-by-wire brake actuation device for a vehicle according to claim 4, characterized in that: the retainer is provided with a first avoidance hole and a second avoidance hole, the accommodating cavity is positioned between the first avoidance hole and the second avoidance hole, and the inner side surface of the accommodating cavity is in clearance contact with the side surface and two end surfaces of the roller; the first avoidance hole and the second avoidance hole are at least provided with a group of bosses, the bosses are used for preventing the rollers from being separated from the containing cavities, and the rollers respectively penetrate through the first avoidance hole and the second avoidance hole and are in contact with the screw rod and the nut.

7. The brake-by-wire brake actuation device for a vehicle according to claim 3, characterized in that: the rollers are arranged in a plurality of numbers, all the rollers are sequentially arranged in the spiral space along the spiral direction, and the cross section of the spiral space is rectangular or trapezoidal.

8. The brake-by-wire brake actuation apparatus for a vehicle according to claim 1 or 2, characterized in that: the retainer is made of elastic steel materials.

9. The brake-by-wire brake actuation apparatus for a vehicle according to claim 1 or 2, characterized in that: the screw rod transmission mechanism further comprises a first limiting part, a second limiting part, a first elastic part and a second elastic part, wherein the first limiting part, the second limiting part, the first elastic part and the second elastic part are arranged in the spiral space, the retainer is located between the first elastic part and the second elastic part, the first elastic part is located between the retainer and the first limiting part, and the second elastic part is located between the retainer and the second limiting part.

10. The brake-by-wire brake actuation device for a vehicle according to claim 9, characterized in that: the first elastic piece and the second elastic piece are both helical springs, and the side surfaces of the enveloping bodies of the first elastic piece and the second elastic piece are matched with the shapes of helical spaces.

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