Compact high-adaptation brake force sensor

Abstract

The present application relates to the field of brake force detection, and particularly relates to a compact high-adaptation brake force sensor. The compact high-adaptation brake force sensor comprises: a force ring, a large hole and a small hole being coaxial and arranged at the central position of the force ring in the axial direction, a convex ring being arranged at the end of the force ring close to the large hole and protruding outward in the radial direction, and a plurality of strain holes being arranged on the outer peripheral wall of the end of the force ring close to the small hole in the circumferential direction; a strain element being attached to the joint surface of the large hole and the small hole; a metal shell being connected with the force ring and not exceeding the convex ring in the axial direction, and forming a mounting cavity together with the inner peripheral wall of the large hole and the joint surface; and a circuit board being mounted in the mounting cavity and electrically connected with the strain element. The present application has low overall height, and can be flexibly adapted to various bearing transmitting brake forces without changing the overall outer diameter size.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of brake force detection, in particular to a compact high-adaptation brake force sensor. BACKGROUND

[0002] The compact high-adaptation brake force sensor is a key component in the vehicle braking system, which is used to monitor and feedback the size of the brake force in real time, and is usually installed in the space-limited parts such as brake calipers.

[0003] The compact high-adaptation brake force sensor generally includes a pressure sensing terminal 10, a sensitive element 20, a circuit board and a shell 30, etc. The upper half of the pressure sensing terminal 10 has a smaller outer diameter than the lower half. The sensitive element 20 is attached to the top of the pressure sensing terminal 10. The circuit board is electrically connected to the sensitive element 20. The shell 30 covers the upper half of the pressure sensing terminal 10 to protect the internal components. The overall sensor structure is in a positive convex shape structure. The step surface of the positive convex shape structure is used as the reaction force surface 17. The bottom of the pressure sensing terminal 10 is provided with an annular stress buffer groove 101. The center area surrounded by the groove and slightly protruding is used as the force receiving surface 16 of the sensor structure. The force receiving surface 16 cooperates with the bearing that transmits the brake force from the outside. For example, the patent with the patent number CN202510312686.6 and the patent name of a brake force sensor has this structure. The specific structure is shown in Figure 1 .

[0004] However, the above structure has the following defects in actual application:

[0005] Firstly, due to the positive convex layout, the overall height is large, especially in the case of large brake force stroke (for example, greater than 70kN), the overall height is particularly large. It is difficult to arrange in the narrow space of the brake caliper and other installation environments, which limits its application in compact brake systems.

[0006] Secondly, the force receiving surface transmits the load through the bearing. If the bearing size is adjusted to adapt to different working conditions, the area of the force receiving surface cooperating with the bearing size will change, which will cause the overall diameter of the sensor to change. This makes the customer strictly limited when selecting the bearing, and the matching of the sensor diameter and the installation space must be considered, which reduces the adaptability and design flexibility of the system. At present, many customers will use customized bearings, which increases the cost.

[0007] Thirdly, the stress buffer groove at the bottom of the sensor essentially makes it a bending beam structure subject to concentrated stress. Under long-term alternating loads, stress easily concentrates in the rounded corner area of ​​the stress buffer groove, causing localized stress fatigue. In durability tests, fatigue cracks and even fractures frequently appeared at these rounded corners, seriously affecting the sensor's service life and measurement reliability, posing a safety hazard. Simulation and testing showed that the localized stress of this structure was excessive, even reaching 1400 MPa.

[0008] Therefore, existing braking force sensors need improvement in terms of structural height, bearing compatibility, and fatigue resistance. There is an urgent need for a new sensor structure that is more compact, reliable, and easy to adapt. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a compact and highly adaptable braking force sensor. It has a low overall height and can be flexibly adapted to various bearings that transmit braking force without changing the overall outer diameter.

[0010] To solve the above-mentioned technical problems, the technical solution of the present invention is: a compact, highly adaptable braking force sensor, comprising:

[0011] The stress ring has a large hole and a small hole coaxially arranged at its center along the axial direction. A convex ring protruding outward in the radial direction is provided at the end near the large hole. Several strain holes are provided on the outer peripheral wall of the end near the small hole along the circumferential direction.

[0012] The strain gauge is attached to the interface between the large hole and the small hole;

[0013] A metal shell, connected to the force-bearing ring, does not extend beyond the convex ring in the axial direction, and together with the inner peripheral wall of the large hole and the interface surface, forms an installation cavity;

[0014] The circuit board is installed inside the mounting cavity and is electrically connected to the strain element.

[0015] Furthermore, the metal shell includes a cover plate portion and a cylindrical body portion that are interconnected; wherein,

[0016] The cover plate is fitted onto the end of the large hole away from the interface, and the cylindrical part is inserted into the small hole.

[0017] Furthermore, the inner peripheral wall of the large hole is provided with a first support surface for supporting the cover plate portion, and the cover plate portion is welded to the first support surface;

[0018] The inner peripheral wall of the small hole is provided with a second support surface for supporting the cylindrical part, and the cylindrical part is welded to the second support surface.

[0019] Furthermore, the compact, highly adaptable braking force sensor also includes a spring frame, which is installed in the mounting cavity and electrically contacts the cover plate, and is also electrically connected to the grounding terminal of the circuit board via a grounding spring.

[0020] Furthermore, the strain element is attached to the interface surface near the edge.

[0021] Furthermore, an arc-shaped groove is provided on the interface surface at a position inside the strain element.

[0022] Furthermore, the circuit board is provided with a clearance opening to avoid the strain element.

[0023] Furthermore, the strain hole is a blind hole.

[0024] Furthermore, the strain holes and strain elements are in one-to-one correspondence, and the corresponding strain holes and strain elements coincide on the axial projection of the force ring.

[0025] By adopting the above technical solution, the present invention has the following beneficial effects:

[0026] The presence of the convex ring at the upper end of the force ring makes the force ring inverted U-shape. The metal shell, which serves as an encapsulation, is built inside and does not extend beyond the force ring in the axial direction. The size of the entire force ring is the size of the entire braking force sensor. The strain element, circuit board, and metal shell are all arranged inside the force ring. The entire braking force sensor has a compact structure and can be made lower than the traditional structure, saving more space for the caliper and meeting the application requirements of compact braking systems.

[0027] This invention uses the small end face of the inverted convex structure as the force-bearing surface for receiving the load transmitted by the bearing. The size of the plane can be changed according to the size of the center face of the bearing without changing the overall outer diameter of the braking force sensor. This makes it convenient for customers to adjust the matching bearing and improves the adaptability and design flexibility of the system.

[0028] This invention places strain holes on the peripheral wall of the stress ring, improving the "bending beam structure" in traditional structures. In addition, the overall structure does not have too many small arcs and chamfers, nor does it have annular grooves, which greatly improves the stress concentration problem. The maximum local stress does not exceed 700 MPa. No fatigue fracture failure problem has been found in the customer's durable application, and the safety factor is high. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a braking force sensor in the prior art;

[0030] Figure 2 This is a schematic diagram of the compact, highly adaptable braking force sensor of the present invention;

[0031] Figure 3 This is a cross-sectional view of the compact, highly adaptable braking force sensor of the present invention;

[0032] Figure 4 This is an exploded view of the compact, highly adaptable braking force sensor of the present invention;

[0033] Figure 5 This is a schematic diagram of the compact, highly adaptable braking force sensor of the present invention after removing the metal shell and spring frame.

[0034] Figure 6 This is a schematic diagram of the structure of the strain element of the compact, highly adaptable braking force sensor of the present invention mounted on a stress ring.

[0035] In the picture:

[0036] 1. Force-bearing ring; 11. Large hole; 111. First support surface; 12. Small hole; 121. Second support surface; 13. Convex ring; 14. Strain gauge hole; 15. Intersection surface; 151. Arc groove; 16. Force-bearing surface; 17. Reaction surface; 2. Strain element; 3. Metal shell; 31. Cover plate; 32. Cylinder body; 4. Circuit board; 41. Clearance opening; 5. Spring frame; 6. Grounding spring;

[0037] 10. Pressure-sensing terminal; 101. Stress buffer groove; 20. Sensing element; 30. Housing. Detailed Implementation

[0038] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0039] like Figures 2 to 6 As shown, a compact, highly adaptable braking force sensor includes:

[0040] The stress ring 1 has a large hole 11 and a small hole 12 coaxially arranged at its center along the axial direction. A convex ring 13 protruding outward in the radial direction is provided at the end near the large hole 11. Several strain holes 14 are provided on the outer peripheral wall of the end near the small hole 12 along the circumferential direction.

[0041] Strain element 2 is mounted on the interface 15 between the large hole 11 and the small hole 12;

[0042] The metal shell 3 is connected to the force-bearing ring 1 and does not extend beyond the convex ring 13 in the axial direction. Together with the inner peripheral wall of the large hole 11 and the interface 15, it forms an installation cavity.

[0043] Circuit board 4 is installed inside the mounting cavity and is electrically connected to strain element 2.

[0044] by Figure 2 and Figure 3For example, this compact, highly adaptable braking force sensor uses the lower end face of the force ring 1 as the force surface 16 and the upper end face of the convex ring 13 as the reaction force surface 17. The reaction force surface 17 is the highest surface of the force ring 1. When braking force is applied to the force surface, the strain element 2 undergoes strain, converting the strain signal into an electrical signal. The circuit board 4 processes the electrical signal and outputs it.

[0045] Specifically, the presence of the convex ring 13 at the upper end of the force-bearing ring 1 makes the force-bearing ring 1 have an inverted U-shape. The metal shell 3, which serves as an encapsulation, is built inside and does not extend beyond the force-bearing ring 1 in the axial direction. The size of the entire force-bearing ring 1 is the size of the entire braking force sensor. In this embodiment, the strain element 2, circuit board 4, and metal shell 3 are all disposed inside the force-bearing ring 1, resulting in a compact overall structure. The height can be made lower than that of traditional structures, saving more space for the caliper and meeting the application requirements of compact braking systems. Furthermore, in this embodiment, the small end face of the inverted U-shaped structure serves as the force-bearing surface 16 for receiving the load transmitted by the bearing, and it is a plane. The size of the plane can be changed according to the size of the center face of the adapted bearing without altering the overall outer diameter of the braking force sensor. This facilitates the customer in adjusting the mating bearing, improving the system's adaptability and design flexibility. Finally, in this embodiment, the strain hole 14 is set on the peripheral wall of the stress ring 1, which improves the "bending beam" structure or "cantilever beam" structure in the traditional structure. In addition, the overall structure does not have too many small arcs and chamfers, nor does it have annular grooves, which greatly improves the stress concentration problem. The local maximum stress does not exceed 700 MPa. No fatigue fracture failure problem was found in the customer's durable application, and the safety factor is high.

[0046] The strain gauge hole 14 can be a through hole or a blind hole, preferably a blind hole. Figure 3 The one shown is a blind hole.

[0047] In some examples, such as Figure 3 As shown, the strain holes 14 and strain elements 2 correspond one-to-one, and the corresponding strain holes 14 and strain elements 2 coincide on the axial projection of the force ring 1.

[0048] The circumferential dimensions of the strain gauge 14 must meet the mounting requirements of the strain element 2; the depth of the strain gauge 14 determines the radial position of the strain element 2 on the interface 15; the vertical position of the strain gauge 14 determines the magnitude of the force range. For example, the lower the position of the strain gauge 14, the greater the thickness of the area where the strain element 2 is located, and the greater the corresponding force range. Therefore, this embodiment can adjust the required force range of a compact, highly adaptable braking force sensor by adjusting the vertical position of the strain gauge 14 without changing the overall outer diameter of the braking force sensor, further improving system adaptability and design flexibility.

[0049] Preferably, four strain elements 2 are provided, and the four strain elements 2 are connected to form a Wheatstone bridge through traces on the circuit board 4. When the strain elements 2 are strained, the output voltage of the Wheatstone bridge changes. The strain elements 2 can be, but are not limited to, silicon-based strain gauges.

[0050] In some examples, such as Figure 3 and Figure 4 As shown, the metal shell 3 includes a cover plate portion 31 and a cylindrical body portion 32 that are connected to each other; wherein,

[0051] The cover plate 31 is installed on the end of the large hole 11 away from the interface 15, and the cylinder 32 is inserted into the small hole 12.

[0052] Specifically, this metal casing 3 allows the entire compact, highly adaptable braking force sensor to be easily packaged into a single unit.

[0053] In some examples, such as Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the inner peripheral wall of the large hole 11 is provided with a first support surface 111 for the cover plate portion 31, and the cover plate portion 31 is welded to the first support surface 111.

[0054] The inner peripheral wall of the small hole 12 is provided with a second support surface 121 for supporting the cylindrical part 32, and the cylindrical part 32 is welded to the second support surface 121.

[0055] Specifically, the metal shell 3 and the force-bearing ring 1 are connected by welding, which simplifies the assembly process. Furthermore, compared to traditional structures, the sealing ring can be omitted, avoiding the impact of sealing ring aging or failure on the entire braking force sensor.

[0056] Furthermore, the upper surface of the cover plate 31 is lower than the upper surface of the force ring 1. In this way, on the one hand, the overall height of the braking force sensor can be relatively small, and on the other hand, the cover plate 31 can be prevented from interfering with or affecting the force on the reaction surface 17.

[0057] In some examples, such as Figure 3 and Figure 4 As shown, the compact, highly adaptable braking force sensor also includes a spring frame 5, which is installed in the mounting cavity and electrically contacts the cover plate 31. The spring frame 5 is also electrically connected to the grounding terminal of the circuit board 4 via a grounding spring 6.

[0058] In some examples, such as Figure 5 and Figure 6 As shown, strain element 2 is mounted near the edge of the interface 15.

[0059] In some examples, such as Figure 4 ,Figure 5 and Figure 6 As shown, an arc-shaped groove 151 is provided on the interface 15 at a position inside the strain element 2.

[0060] Specifically, the arc groove 151 can make the patch area of ​​the strain element 2 form an island, avoiding the influence of the assembly between the metal shell 3 and the force ring 1 on the strain, so that the entire compact high-adaptability braking force sensor maintains high sensitivity to the "measured force" and high inertia to "assembly interference", thereby improving the accuracy of the compact high-adaptability braking force sensor.

[0061] In some examples, such as Figure 5 and Figure 6 As shown, the circuit board 4 is provided with a clearance opening 41 to avoid the strain element 2. In addition, if an aluminum wire binding device is used to bind the wire, a clearance groove needs to be reserved on the force ring 1. If a gold wire binding device is used to bind the wire, it is not necessary to reserve a clearance groove on the force ring 1.

[0062] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A compact, highly adaptable braking force sensor, characterized in that, include: The stress ring (1) has a large hole (11) and a small hole (12) arranged axially at its center position. A convex ring (13) protruding outward in the radial direction is provided at the end near the large hole (11). Several strain holes (14) are provided on the outer peripheral wall of the end near the small hole (12) in the circumferential direction. The strain element (2) is attached to the interface (15) between the large hole (11) and the small hole (12); The metal shell (3) is connected to the force-bearing ring (1), and does not extend beyond the convex ring (13) in the axial direction. It together with the inner peripheral wall of the large hole (11) and the interface (15) to form an installation cavity. The circuit board (4) is installed in the mounting cavity and is electrically connected to the strain element (2); Among them, the lower end face of the force-bearing ring (1) is used as the force-bearing surface (16), and the upper end face of the convex ring (13) is used as the reaction force surface (17).

2. The compact, highly adaptable braking force sensor according to claim 1, characterized in that, The metal shell (3) includes a cover plate portion (31) and a cylindrical body portion (32) that are connected to each other; wherein, The cover plate (31) is fitted over the end of the large hole (11) away from the interface (15), and the cylindrical body (32) is inserted into the small hole (12).

3. The compact, highly adaptable braking force sensor according to claim 2, characterized in that, The inner peripheral wall of the large hole (11) is provided with a first support surface (111) for supporting the cover plate part (31), and the cover plate part (31) is welded to the first support surface (111); The inner peripheral wall of the small hole (12) is provided with a second support surface (121) for supporting the cylindrical part (32), and the cylindrical part (32) is welded to the second support surface (121).

4. The compact, highly adaptable braking force sensor according to claim 3, characterized in that, It also includes a spring frame (5), which is installed in the mounting cavity and is in electrical contact with the cover plate (31), and is also electrically connected to the grounding terminal of the circuit board (4) through a grounding spring (6).

5. The compact, highly adaptable braking force sensor according to any one of claims 1 to 4, characterized in that, The strain element (2) is attached to the junction surface (15) near the edge.

6. The compact, highly adaptable braking force sensor according to claim 5, characterized in that, An arc-shaped groove (151) is provided on the interface (15) at the position inside the strain element (2).

7. The compact, highly adaptable braking force sensor according to claim 1, characterized in that, The circuit board (4) is provided with a clearance opening (41) to avoid the strain element (2).

8. The compact, highly adaptable braking force sensor according to claim 1, characterized in that, The strain hole (14) is a blind hole.

9. The compact, highly adaptable braking force sensor according to claim 1, characterized in that, The strain holes (14) and the strain elements (2) correspond one-to-one, and the corresponding strain holes (14) and strain elements (2) coincide on the axial projection of the force ring (1).

10. The compact, highly adaptable braking force sensor according to claim 1, characterized in that, The strain element (2) is a silicon-based strain gauge.

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