A new driving device for electronic parking drum brake

Abstract

The present invention discloses a novel driving device of an electronic parking drum brake, comprising a housing, the housing being provided with a hydraulic transmission mechanism, a mechanical transmission mechanism and a spring force transmission mechanism, the hydraulic transmission mechanism comprising a piston, a rectangular sealing ring, a piston return spring and a piston push rod, a closed hydraulic chamber being formed between the housing, the piston and the rectangular sealing ring; the spring force transmission mechanism sliding in the housing, the spring force transmission mechanism comprising a spring, a spring sleeve and a spring push rod; the mechanical transmission mechanism comprising a needle bearing, a worm wheel, a worm, a screw sleeve and a stop ring, the screw sleeve being sleeved on the piston push rod, the screw sleeve being matched with the thread in the internal thread hole through the transmission thread; the inner end face of the flange of the piston push rod is in contact with the outer end face of the screw sleeve, and the outer end face of the piston push rod is in contact with the inner end face of the spring sleeve. The above technical scheme has reasonable structural design, simple structure, small volume, convenient use, reliable operation and good practicality.

Description

Technical Field

[0001] The invention relates to the technical field of brakes, and in particular to a novel driving device of an electronic parking drum brake. Background Art

[0002] At present, the parking drive mechanisms of the existing electronic parking drum brakes are roughly divided into two types. The first type is a pull-wire type electronic parking mechanism with an external motor and a pull-rod type electronic parking mechanism with a built-in motor; the second type is a combined mechanism, in which the motor and the reduction mechanism are external, the brake shoe support seat in the bottom plate is replaced by a thrust mechanism, and the motor, reduction mechanism and thrust mechanism are combined into a drive mechanism.

[0003] The pull-wire (rod) type electronic parking mechanism has a motor externally or internally mounted on the brake base plate of the drum brake. The drive mechanism is connected to the pull arm of the drum brake through a pull cable or a pull rod. The power of the motor is decelerated by a reduction mechanism and converted into the linear motion of the screw through a screw sleeve mechanism. The screw is connected to the brake cable or pull rod, so that the reciprocating linear motion of the screw is transmitted to the pull arm, thereby realizing the parking and release functions.

[0004] The power of the motor of the combined drive mechanism is directly transmitted to the brake shoe of the drum brake through the reduction mechanism and the thrust mechanism in the base plate, realizing the parking and releasing functions.

[0005] The first type of wire (rod) type electronic parking mechanism has the following problems: the motor and the reduction mechanism need to be directly arranged on the brake base plate, the external motor occupies a large suspension arrangement space, and the internal motor has limited power due to the limitation of the space inside the drum; and the driving mechanism drives the brake arm through a wire or a rod, which is highly flexible, has a long screw stroke, and a long parking system response time; the second type of combined driving mechanism has the following problems: the thrust mechanism is complex; the reduction mechanism has many parts, the power transmission path is long, and the efficiency is low; and correspondingly, the parking system response time is also long. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a new type of driving device for an electronic parking drum brake which has a reasonable structural design, a simple structure, a small size, is easy to use, works reliably and has good practicality.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a new type of driving device for an electronic parking drum brake, comprising a housing, the housing being provided with a hydraulic transmission mechanism, a mechanical transmission mechanism and a spring force transmission mechanism, the hydraulic transmission mechanism comprising a piston, a rectangular sealing ring, a piston return spring and a piston push rod, a closed hydraulic chamber being formed between the housing, the piston and the rectangular sealing ring; the spring force transmission mechanism slides in the housing, the spring force transmission mechanism comprising a spring, a spring sleeve and a spring push rod; the mechanical transmission mechanism comprises a needle bearing, a worm wheel, a worm, a screw sleeve and a stop ring, the screw sleeve is sleeved on the piston push rod, the outer surface of the screw sleeve is provided with a transmission thread, the worm wheel is provided with an internal threaded hole, the screw sleeve matches the thread in the internal threaded hole through the transmission thread; the inner end face of the flange of the piston push rod contacts the outer end face of the screw sleeve, and the outer end face of the piston push rod contacts the inner end face of the spring sleeve.

[0008] The present invention is further configured as follows: during service braking, hydraulic oil enters the closed hydraulic cavity, the piston pushes the piston push rod to move, the piston push rod pushes the spring sleeve to move, and the spring sleeve drives the spring push rod to move; when the hydraulic oil in the closed hydraulic cavity is unloaded, the piston return spring returns the piston under the action of elastic force, and the spring push rod returns.

[0009] The present invention is further configured such that during parking braking, the worm gear is driven to rotate by the worm, the worm gear is threadedly connected to the screw sleeve, and the rotational motion of the worm gear is converted into linear motion by the screw sleeve.

[0010] The present invention is further configured such that: the forward rotation or reverse rotation of the worm causes the screw sleeve to produce a reciprocating motion, thereby realizing the action of the screw sleeve pushing the piston push rod.

[0011] The present invention is further configured such that when the parking is released, the screw sleeve is driven by the worm gear to return to its original position, and the piston push rod is driven by the spring sleeve of the spring force transmission mechanism to return to its original position.

[0012] The present invention is further configured as follows: a spring seat is also provided, and when the service brake and the parking brake act simultaneously, an input force superposition effect occurs, and the excess force is transmitted to the outside through the spring seat.

[0013] The advantages of the present invention are: compared with the prior art, the present invention has a more reasonable structure, and combines the functions of the brake cylinder, parking mechanism and other mechanisms of the original drum brake. Through the present invention, the external motor or hydraulic unit can drive the brake shoe of the drum brake alone or simultaneously to achieve the function of driving brake or parking brake;

[0014] The driving device of the present invention is small in size and can be applied to a 9-inch drum brake at the smallest. The drum brake equipped with the mechanism is convenient to arrange on the suspension.

[0015] Since the drive device of the present invention, whether it is hydraulic drive or parking drive, realizes rigid transmission under normal use conditions, it can overcome the shortcomings of flexible drive and long response time of existing mechanisms, and has a simple structure, small size, easy use, reliable operation and good practicality.

[0016] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0018] Figure 2 A partial cross-sectional view of an embodiment of the present invention Figure 1 ;

[0019] Figure 3 A partial cross-sectional view of an embodiment of the present invention Figure 2 ;

[0020] Figure 4 A partial cross-sectional view of an embodiment of the present invention Figure 3 . DETAILED DESCRIPTION

[0021] In the description of this embodiment, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "back", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore, it cannot be understood as a limitation on the present invention. In addition, if the terms "first", "second", and "third" appear, they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0022] See also Figure 1 , Figure 2 , Figure 3 and Figure 4The present invention discloses a novel driving device of an electronic parking drum brake, comprising a housing B1, wherein the housing is provided with a hydraulic transmission mechanism, a mechanical transmission mechanism and a spring force transmission mechanism, wherein the hydraulic transmission mechanism comprises a piston B2, a rectangular sealing ring B3, a piston return spring B4 and a piston push rod B10, and a closed hydraulic cavity is formed between the housing B1, the piston B2 and the rectangular sealing ring B3; the spring force transmission mechanism slides in the housing B1, and the spring force transmission mechanism comprises a spring B11, a spring sleeve B13 and a spring Push rod B12; the mechanical transmission mechanism includes a needle bearing B5, a worm wheel B6, a worm B7, a screw sleeve B8 and a stop ring B9, the screw sleeve B8 is mounted on the piston push rod B10, the outer surface of the screw sleeve B8 is provided with a transmission thread, the worm wheel B6 is provided with an internal threaded hole, and the screw sleeve B8 matches the thread in the internal threaded hole through the transmission thread; the inner end face of the flange of the piston push rod B10 contacts the outer end face of the screw sleeve B8, and the outer end face of the piston push rod B10 contacts the inner end face of the spring sleeve B13.

[0023] As a preferred embodiment, all parts are assembled in the housing B1, which is fixed to the brake base plate of the existing drum brake, and the spring push rod B12 cooperates with other brake elements in the drum brake to drive the brake shoe of the drum brake to open, thereby realizing the driving or parking brake of the vehicle. The spring force transmission mechanism can freely slide back and forth in the housing B1.

[0024] During the service brake, the hydraulic oil enters the closed hydraulic chamber, the piston B2 pushes the piston push rod B10 to move, the piston push rod B10 pushes the spring sleeve B13 to move, and the spring sleeve B13 drives the spring push rod B12 to move; when the hydraulic oil in the closed hydraulic chamber is unloaded, the piston return spring B4 returns the piston B2 under the action of elastic force, and the spring push rod B12 returns. As a preferred embodiment, in this embodiment, the hydraulic oil from the external hydraulic unit enters the closed hydraulic chamber, and pushes the piston push rod B10 through the piston B2. Since the piston push rod B10 contacts the spring sleeve B13, the movement of the piston B2 is transmitted to the spring force transmission mechanism. The spring push rod B12 cooperates with other brake elements in the drum brake to drive the brake shoe to open, so as to realize the braking of the drum brake; when the hydraulic pressure in the hydraulic chamber is unloaded, the piston return spring B4 returns the piston B2, and the spring push rod B12 returns under the push of the brake elements in the brake, and the brake is released.

[0025] When parking brake, see Figure 4 , B14 is the driving motor, B15 is the motor mounting screw, B16 is the bleed screw, and B17 is the bleed screw cap.

[0026] Since the input shaft of the driving motor is connected to the worm B7 through a spline, the input shaft of the driving motor rotates, drives the worm wheel B6 to rotate through the worm B7, and the worm wheel B6 is threadedly connected to the screw sleeve B8, and the rotational motion of the worm wheel B6 is converted into a linear motion through the screw sleeve B8. The positive rotation or reverse rotation of the worm B7 causes the screw sleeve B8 to produce a reciprocating motion, so that the screw sleeve B8 pushes the piston push rod B10 to move. As a preferred embodiment, since the input shaft of the motor is connected to the worm B7 through a spline, the rotational motion from the motor shaft drives the worm wheel B6 to rotate through the worm B7; the worm wheel B6 is threadedly connected to the screw sleeve B8, and the screw sleeve B8 converts the rotational motion of the worm wheel B6 into a linear motion; the positive and reverse rotation of the worm B7 will cause the screw sleeve B8 to produce a reciprocating motion. In this way, the screw sleeve B8 pushes the piston push rod B10 when parking.

[0027] When the parking is released, the screw sleeve B8 is driven by the worm gear B6 to return to the reverse position, and the piston push rod B10 is driven by the spring sleeve B13 of the spring force transmission mechanism to return to the reverse position.

[0028] The present invention is also provided with a spring seat, and when the service brake and the parking brake act at the same time, the input force superposition effect occurs, and the excess force is transmitted to the outside through the spring seat. Preferably, when the service brake and the parking brake act at the same time, the input force superposition effect occurs, and the driving device of the present invention can transmit the excess force to the outside of the driving device through the spring seat, so that the driving device of the present invention itself will not be overloaded.

[0029] In actual application, the structure of the present invention is more reasonable, and the functions of the brake cylinder, parking mechanism and other mechanisms of the original drum brake are integrated. Through the present invention, the external motor or hydraulic unit can drive the brake shoe of the drum brake alone or simultaneously to realize the function of driving brake or parking brake.

[0030] The driving device of the present invention is small in size and can be applied to a 9-inch drum brake at the smallest. The drum brake equipped with the mechanism is convenient to arrange on the suspension.

[0031] Since the drive device of the present invention, whether it is hydraulic drive or parking drive, realizes rigid transmission under normal use conditions, it can overcome the shortcomings of flexible drive and long response time of existing mechanisms, and has a simple structure, small size, easy use, reliable operation and good practicality.

[0032] The specific description of the present invention in the above embodiments is only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Technical engineers in this field may make some non-essential improvements and adjustments to the present invention based on the contents of the above invention, which fall within the scope of protection of the present invention.

Claims

1. A novel driving device for an electronic parking drum brake, comprising a housing (B1), characterized in that: The housing is provided with a hydraulic transmission mechanism, a mechanical transmission mechanism and a spring force transmission mechanism. The hydraulic transmission mechanism includes a piston (B2), a rectangular sealing ring (B3), a piston return spring (B4) and a piston push rod (B10). A closed hydraulic chamber is formed between the housing (B1), the piston (B2) and the rectangular sealing ring (B3); the spring force transmission mechanism slides in the housing (B1), and the spring force transmission mechanism includes a spring (B11), a spring sleeve (B13) and a spring push rod (B12); the mechanical transmission mechanism includes a needle roller shaft A bearing (B5), a worm wheel (B6), a worm (B7), a screw sleeve (B8) and a stop ring (B9), wherein the screw sleeve (B8) is sleeved on the piston push rod (B10), the outer surface of the screw sleeve (B8) is provided with a transmission thread, the worm wheel (B6) is provided with an internal threaded hole, and the screw sleeve (B8) matches the thread in the internal threaded hole through the transmission thread; the inner end face of the flange of the piston push rod (B10) contacts the outer end face of the screw sleeve (B8), and the outer end face of the piston push rod (B10) contacts the inner end face of the spring sleeve (B13); The input shaft of the driving motor is connected to the worm (B7) through a spline. The input shaft of the driving motor rotates, and the worm gear (B6) is driven to rotate through the worm (B7). The worm gear (B6) is threadedly connected to the screw sleeve (B8), and the rotational motion of the worm gear (B6) is converted into linear motion through the screw sleeve (B8).

2. The novel driving device of the electronic parking drum brake according to claim 1 is characterized in that: During service braking, hydraulic oil enters the sealed hydraulic cavity, the piston (B2) pushes the piston push rod (B10) to move, the piston push rod (B10) pushes the spring sleeve (B13) to move, and the spring sleeve (B13) drives the spring push rod (B12) to move; when the hydraulic oil in the sealed hydraulic cavity is discharged, the piston return spring (B4) returns the piston under the action of elastic force, and the spring push rod (B12) returns.

3. The novel driving device of the electronic parking drum brake according to claim 2 is characterized in that: When the parking brake is applied, the worm gear (B6) is driven to rotate by the worm (B7), the worm gear (B6) is threadedly connected to the screw sleeve (B8), and the rotational motion of the worm gear (B6) is converted into linear motion by the screw sleeve (B8).

4. The novel driving device of the electronic parking drum brake according to claim 3 is characterized in that: The forward or reverse rotation of the worm (B7) causes the screw sleeve (B8) to generate a reciprocating motion, thereby realizing the action of the screw sleeve (B8) pushing the piston push rod (B10).

5. The novel driving device of the electronic parking drum brake according to claim 4 is characterized in that: When the parking brake is released, the screw sleeve (B8) is driven by the worm gear (B6) to return to the reverse position, and the piston push rod (B10) is returned to the reverse position under the action of the spring sleeve (B13) of the spring force transmission mechanism.

6. A novel driving device for an electronic parking drum brake according to claim 1 or 5, characterized in that: A spring seat is also provided. When the service brake and the parking brake act at the same time, an input force superposition effect occurs, and the excess force is transmitted to the outside through the spring seat.

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