Double-backstop nut and screw transmission mechanism applied to heavy-load electronic parking brake

Abstract

The utility model relates to the technical field of braking systems, in particular to a double-backstop nut and screw transmission mechanism applied to a heavy-load electronic parking brake. A double-backstop nut and screw transmission mechanism applied to a heavy-load electronic parking brake is characterized in that a threaded section of a double-backstop screw is in threaded connection with a double-backstop nut, the rod portion of the double-backstop screw is sleeved with a thrust bearing, and the front side and the rear side of the thrust bearing are sleeved with gaskets respectively; the threaded section of the double-stop screw is of a single-line thread structure, a stop disc is arranged between the threaded section and the rod portion of the double-stop screw, and two stop bosses are arranged on the stop disc. The double-backstop nut is of a T-shaped structure, and the end of the double-backstop nut is provided with a double-backstop structure matched with the two backstop bosses of the double-backstop screw. Compared with the prior art, a single-line large-lead thread transmission and double-backstop structure is designed, the performance balance problem of thread strength and transmission efficiency is solved, and the backstop strength is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of braking systems, specifically a double-stop nut-screw transmission mechanism applied to heavy-duty electronic parking brakes. Background Art

[0002] An electronic parking brake integrates the temporary braking during driving and the long-term braking after parking, and realizes the parking braking technology by an electronic control method. The components related to the movement of the electronic parking brake include an actuator, a linear motion mechanism, a piston, brake pads, etc. Its specific working process is divided into 3 steps:

[0003] 1. Applying braking force: The actuator of the electronic parking brake works, outputs a positive-direction torque, drives the screw to rotate in the positive direction, through the thread fit with the nut, pushes the nut to move linearly to the left, and then pushes the piston and the brake pads, and the brake pads clamp the brake disc to form a braking force;

[0004] 2. Maintaining the braking force: After the vehicle stops, the actuator of the electronic parking brake stops working. At the same time, the nut-screw transmission mechanism has a self-locking performance and continues to maintain the mechanical clamping force;

[0005] 3. Releasing the braking force: The actuator of the electronic parking brake works, outputs a reverse-direction torque, drives the screw to rotate in the reverse direction, through the thread fit with the nut, pushes the nut to move linearly to the right, and then disengages from the piston. Since the piston and the brake pads are in a relatively free state, the braking force is thus released.

[0006] For vehicles with a load of more than 2.5 tons in the market, it is necessary to adapt to heavy-duty electronic parking brakes. For the nut-screw transmission mechanism, higher requirements are put forward for the strength of the screw thread, transmission efficiency, and stop performance. Therefore, the present invention innovatively designs a single-thread large-lead screw thread transmission and a double-stop structure design. Summary of the Invention

[0007] The utility model aims to overcome the deficiencies of the prior art, and provides a double-stop nut-screw transmission mechanism applied to heavy-duty electronic parking brakes, which designs a single-thread large-lead screw thread transmission and a double-stop structure, not only solves the performance balance problem of the screw thread strength and transmission efficiency, but also improves the stop strength.

[0008] To achieve the above object, a double-stop nut-screw transmission mechanism applied to heavy-duty electronic parking brakes is designed, including a double-stop nut, a double-stop screw, a gasket, and a thrust bearing. It is characterized in that: the double-stop nut is threadedly connected to the threaded section of the double-stop screw, the rod part of the double-stop screw is sleeved with a thrust bearing, and gaskets are respectively sleeved on the front and rear sides of the thrust bearing;

[0009] The threaded section of the double-stop screw is a single-threaded structure, and a stop disc is provided between the threaded section and the rod portion of the double-stop screw. Two stop bosses are provided on the stop disc;

[0010] The double-stop nut is of a T-shaped structure. An internal thread matching the threaded section of the double-stop screw is provided inside the double-stop nut, and a double-stop structure matching the two stop bosses of the double-stop screw is provided at the end of the double-stop nut.

[0011] The pitch of the threaded section of the double-stop screw is 2.5 mm, one flank angle of the thread of the threaded section of the double-stop screw is 30°, and the other flank angle of the thread of the threaded section of the double-stop screw is 9°.

[0012] The stop disc of the double-stop screw is of an arc-shaped disc structure.

[0013] The two stop bosses are arranged in central symmetry.

[0014] The stop overlapping height of the two stop bosses is greater than or equal to 0.6 mm, and the width of the two stop bosses is 4 mm.

[0015] The double-stop structure of the double-stop nut is composed of two helically rising 90° slope-shaped bosses. The boss width of the two slope-shaped bosses is 3 mm, and the two slope-shaped bosses are arranged in central symmetry.

[0016] Compared with the prior art, the present utility model provides a double-stop nut-screw transmission mechanism applied to a heavy-duty electronic parking brake, designs a single-thread large-lead screw transmission and a double-stop structure, not only solves the performance balance problem of screw thread strength and transmission efficiency, but also improves the stop strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an exploded view of the structure of the present utility model.

[0018] Figure 2 It is a three-dimensional view of the double-stop screw structure in the present utility model.

[0019] Figure 3 It is a three-dimensional view of the double-stop nut structure in the present utility model.

[0020] Figure 4 It is a three-dimensional view of the gasket structure in the present utility model.

[0021] Figure 5 It is a three-dimensional view of the thrust bearing structure in the present utility model.

[0022] Figure 6 It is a schematic diagram of the stop overlapping height of the two stop bosses in the double-stop screw.

[0023] Figure 7 Schematic diagram of the width of the stop boss on the double-stop screw

[0024] Figure 8 Schematic diagram of the helix angle of the double-stop knot in the double-stop nut

[0025] Figure 9 Partial cross-sectional view of the thread in the double-stop screw

[0026] Figure 10 Cross-sectional view of the structure of the present utility model installed in an electronic parking brake

[0027] See Figures 1 to 3 , 1 is a double-stop nut, 1-1 is a double-stop structure, 2 is a double-stop screw, 2-1 is a stop disc, 2-2 is a stop boss, 3 is a gasket, and 4 is a thrust bearing

[0028] See Figure 10 , 5 is the internal spline of the double-stop screw, 6 is the external spline of the electronic parking brake actuator, 7 is the electronic parking brake actuator, 8 is the brake pad, 9 is the piston, 10 is the caliper housing, and 11 is the electronic parking brake Specific embodiments

[0029] The following further describes the present utility model with reference to the accompanying drawings

[0030] As Figures 1 to 9 shown, the double-stop nut 1 is threadedly connected to the threaded section of the double-stop screw 2. A thrust bearing 4 is sleeved on the rod portion of the double-stop screw 2, and gaskets 3 are sleeved on both the front and rear sides of the thrust bearing 4; the threaded section of the double-stop screw 2 has a single-threaded tooth structure, and a stop disc 2-1 is provided between the threaded section and the rod portion of the double-stop screw 2. Two stop bosses 2-2 are provided on the stop disc 2-1; the double-stop nut 1 has a T-shaped structure, an internal thread matching the threaded section of the double-stop screw 2 is provided inside the double-stop nut 1, and a double-stop structure 1-1 matching the two stop bosses 2-2 of the double-stop screw 2 is provided at the end of the double-stop nut 1

[0031] The pitch of the threaded section of the double-stop screw 2 is 2.5 mm, and one flank angle of the thread tooth of the threaded section of the double-stop screw 2 is 30°, and the other flank angle of the thread tooth of the threaded section of the double-stop screw 2 is 9°

[0032] The stop disc 2-1 of the double-stop screw 2 has an arc-shaped disc structure

[0033] The two stop bosses 2-2 are arranged symmetrically about the center

[0034] The stop overlapping height of the two stop bosses 2-2 is greater than or equal to 0.6 mm, and the width of the two stop bosses 2-2 is 4 mm

[0035] The double-stop structure 1-1 of the double-stop nut 1 is composed of two helically rising 90° slope-shaped bosses. The width of the bosses of the two slope-shaped bosses is 3 mm, and the two slope-shaped bosses are symmetrically arranged about the center.

[0036] As Figure 9 shown, while increasing the thread profile of the threaded section of the double-stop screw 2, that is, a single-thread screw tooth with a pitch of 2.5 mm, the axial fit clearance between the internal and external screw teeth is adjusted. A smaller flank angle of 9° is designed in the direction of the clamping force of the electronic parking brake, and a larger flank angle of 30° is designed in the direction of the release braking force of the electronic parking brake, thus meeting both the screw tooth strength and the transmission efficiency requirements.

[0037] As Figure 6 shown, the minimum required overlapping height of the two stop bosses 2-2 on the stop disc 2-1 is 0.6 mm. As Figure 7 shown, it is the double-stop structure of the screw part of the double-stop screw 2. The width of the stop boss 2-2 is 4 mm, and the stop surfaces of the two stop bosses 2-2 are symmetric about the center. As Figure 8 shown, it is the double-stop structure 1-1 of the double-stop nut 1 part. The stop surfaces of the two slope-shaped bosses are symmetric about the center. The slope-shaped bosses helically rise 90°, and the surface width of the slope-shaped bosses is 3 mm; among them, the reasonable design of the boss width is conducive to 100% detection of the stop overlapping height by the production line image detector and can also improve the stop strength.

[0038] As Figure 10 shown, the present utility model is placed inside the caliper housing 10. The internal spline 5 of the double-stop screw 2 is connected to the external spline 6 of the electronic parking brake actuator 7. The outer conical surface of the double-stop nut 1 is in contact with the inner conical surface of the piston 9 during the clamping operation and has a gap during the release operation.

[0039] The working principle of the present utility model:

[0040] 1. Applying braking force: When the electronic parking brake 11 performs the clamping operation, the electronic parking brake actuator 7 outputs a positive-direction torque. Through the external spline 6 of the electronic parking brake actuator 7, the torque is transmitted to the internal spline 5 of the double-stop screw 2. Through the thread fit of the double-stop screw 2 and the double-stop nut 1, the rotational motion of the double-stop screw 2 is converted into the linear motion of the double-stop nut 1. After the gap between the outer conical surface of the double-stop nut 1 and the inner conical surface of the piston 9 is eliminated, the double-stop nut 1 pushes the piston 9 to perform a linear motion together, and then pushes the brake pad 8 to apply a clamping force to the brake disc, achieving the braking effect.

[0041] 2. Maintaining braking force: When the vehicle stops, the electronic parking brake actuator 7 stops working. The structure of the present utility model is designed with a self-locking performance, and the electronic parking brake 11 can continue to maintain the mechanical clamping force.

[0042] 3. Braking force release: When the electronic parking brake 11 performs the release operation, the electronic parking brake actuator 7 outputs torque in the reverse direction. Through the external spline 6 of the electronic parking brake actuator 7, the torque is transmitted to the internal spline 5 of the double-stop screw 2. Through the thread fit between the double-stop screw 2 and the double-stop nut 1, the reverse rotational movement of the double-stop screw 2 is converted into the reverse linear movement of the double-stop nut 1. A gap begins to form between the outer conical surface of the double-stop nut 1 and the inner conical surface of the piston 9, and the double-stop nut 1 is disengaged from the piston 9. Since the piston 9 and the brake pads 8 are in a relatively free state, the braking force is thus released.

Claims

1. A double-stop nut screw transmission mechanism used for a heavy-duty electronic parking brake, comprising a double-stop nut, a double-stop screw, a gasket, and a thrust bearing, characterized in that: The threaded section of the double-stop screw (2) is threadedly connected to the double-stop nut (1); a thrust bearing (4) is sleeved on the rod portion of the double-stop screw (2); and washers (3) are sleeved on the front and rear sides of the thrust bearing (4); The threaded section of the double-stop screw (2) is a single-thread structure, and a stop plate (2-1) is provided between the threaded section and the rod portion of the double-stop screw (2), and two stop bosses (2-2) are provided on the stop plate (2-1); The double stop nut (1) is a T-shaped structure, an internal thread matching the threaded section of the double stop screw (2) is provided on the inner side of the double stop nut (1), and a double stop structure (1-1) matching the two stop bosses (2-2) of the double stop screw (2) is provided at the end of the double stop nut (1).

2. The double-stop nut screw transmission mechanism for heavy-duty electronic parking brake according to claim 1, characterized in that: The pitch of the threaded section of the double-stop screw (2) is 2.5 mm, one flank angle of the thread of the threaded section of the double-stop screw (2) is 30°, and the other flank angle of the thread of the threaded section of the double-stop screw (2) is 9°.

3. The double-stop nut screw transmission mechanism for heavy-duty electronic parking brake according to claim 1, characterized in that: The stop disk (2-1) of the double stop screw (2) is an arc-shaped disk structure.

4. The double-stop nut screw transmission mechanism for heavy-duty electronic parking brake according to claim 1, characterized in that: The two stop bosses (2-2) are centrally symmetrically arranged.

5. The double-stop nut screw transmission mechanism for heavy-duty electronic parking brake according to claim 1 or 4, characterized in that: The stop overlap height of the two stop bosses (2-2) is greater than or equal to 0.6 mm, and the width of the two stop bosses (2-2) is 4 mm.

6. The double-stop nut screw transmission mechanism for heavy-duty electronic parking brake according to claim 1, characterized in that: The double stop structure (1-1) of the double stop nut (1) is composed of two spirally ascending 90° sloped bosses, the boss width of the two sloped bosses is 3 mm, and the two sloped bosses are centrally symmetrically arranged.

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