Gear and rack type steering sensor calibration fixture

Abstract

This utility model discloses a calibration fixture for a rack and pinion steering sensor, including a positioning seat, a positioning post, a torque wrench, and a counterweight. The positioning seat is equipped with a coupling for engaging with a protrusion on the worm gear. The positioning post is equipped with a pressure block for abutting against the steering gear housing. The pressure block is coaxially aligned with the coupling. One end of the torque wrench is connected to the gear shaft, and the other end is connected to the counterweight. The worm gear is axially fixed by the engagement of the coupling with the worm gear protrusion and the pressure block against the steering gear housing, thereby indirectly fixing the gear shaft (sensor body) integrated with the worm gear, avoiding sensor damage caused by direct clamping. The counterweight applies a calibration torque of 7 Nm through the torque wrench, achieving rapid and accurate loading and improving calibration efficiency.

Description

Technical Field

[0001] This utility model relates to the field of sensor calibration technology, specifically to a calibration fixture for a rack and pinion steering sensor. Background Technology

[0002] In the electric power steering industry, ensuring linear steering assist is crucial. To achieve this, the sensor needs to be calibrated by applying external force during operation. The conventional approach involves fixing the gear shaft (on which the sensor body is welded) while rotating the input shaft, thus establishing a linear relationship between the applied force and the sensor's magnetic field. Common calibration processes typically use two torque points: 0 Nm and 7 Nm. 0 Nm corresponds to calibration with no external force on the sensor, while 7 Nm corresponds to calibration with 7 Nm of torque applied. Current technology requires directly clamping and fixing the gear shaft itself (on which the sensor body is welded). The gear shaft is a core component of the steering gear, and its surface precision and finish are extremely sensitive. During clamping, the hard contact between the clamp and the gear shaft can easily cause dents, scratches, and even micro-deformation. Utility Model Content

[0003] To address the aforementioned technical problems, this utility model proposes a gear and rack type steering sensor calibration fixture. By engaging the coupling with the worm gear protrusion and abutting the pressure block against the steering gear housing, the worm gear is axially fixed, thereby indirectly fixing the gear shaft integrated with the worm wheel and avoiding damage to the gear shaft caused by direct clamping.

[0004] The technical solution adopted by this utility model is as follows: A gear and rack type steering sensor calibration fixture includes a positioning seat, a positioning column, a torque wrench and a counterweight. The positioning seat is provided with a coupling for cooperating with a protrusion on the worm gear. The positioning column is provided with a pressure block for abutting against the steering gear housing. The pressure block is coaxially and correspondingly arranged with the coupling. One end of the torque wrench is used to connect to the gear shaft, and the other end of the torque wrench is connected to the counterweight.

[0005] Optionally, the coupling includes a first connecting part and a second connecting part connected to the first connecting part. The first connecting part is provided with a plurality of slots spaced apart along the circumference for engaging with the worm gear protrusions. The second connecting part is fixedly connected to the positioning seat.

[0006] Optionally, the diameter of the first connecting part is larger than the diameter of the second connecting part. The positioning seat is provided with a first through hole and a second through hole communicating with the first through hole. The first connecting part is located in the first through hole, and the groove protrudes from the first through hole. One end of the second connecting part is located in the first through hole, and the other end of the second connecting part is movably located in the second through hole. A spring is provided on the outer peripheral wall of the second connecting part. One end of the spring abuts against the bottom surface of the first connecting part, and the other end of the spring abuts against the bottom wall of the first through hole.

[0007] Optionally, the positioning seat is provided with a positioning pin for engaging with a groove in the steering gear housing.

[0008] Optionally, the second connecting part has a first plane on both side walls, and the second through hole has a second plane that fits with the first plane.

[0009] Optionally, the torque wrench is provided with an adapter sleeve, and the inner peripheral wall of the adapter sleeve is provided with a spline for engagement with the worm gear shaft.

[0010] Optionally, the torque wrench is connected to the counterweight via a connecting belt, one end of the torque wrench is connected to the adapter sleeve, and the other end of the torque wrench is provided with a hook groove for connecting to the connecting belt.

[0011] Optionally, a base plate is also included, with the positioning seat and positioning column respectively installed on the top surface of the base plate.

[0012] The beneficial effects of this utility model are: by engaging the coupling with the worm gear protrusion and by abutting the pressure block against the steering gear housing, the worm gear is axially fixed, thereby indirectly fixing the gear shaft (sensor body) integrated with the worm wheel, avoiding sensor damage caused by direct clamping; the counterweight is applied with a torque wrench to achieve rapid and accurate loading of 7Nm torque, improving calibration efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the gear and rack type steering sensor calibration fixture proposed in an embodiment of this utility model;

[0014] Figure 2 This is a cross-sectional view of the gear and rack type steering sensor calibration fixture proposed in an embodiment of this utility model;

[0015] Figure 3 This is a schematic diagram of the positioning seat and positioning column of the gear and rack type steering sensor calibration fixture proposed in this embodiment of the utility model;

[0016] Figure 4 This is a schematic diagram of the coupling of the gear and rack type steering sensor calibration fixture proposed in this embodiment of the utility model;

[0017] Figure 5 This is a schematic diagram of the positioning seat of the gear and rack type steering sensor calibration fixture proposed in an embodiment of this utility model.

[0018] The markings in the attached figures are as follows: 1. Positioning seat; 11. First through hole; 12. Second through hole; 121. Second plane; 13. Positioning pin; 2. Positioning post; 21. Pressure block; 3. Coupling; 31. First connecting part; 311. Slot; 32. Second connecting part; 321. First plane; 33. Spring; 4. Torque wrench; 41. Connecting sleeve; 42. Hook groove; 5. Counterweight block; 51. Connecting belt; 6. Base plate; 7. Gear shaft; 8. Steering gear housing; 9. Worm gear; 91. Protrusion. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0020] like Figures 1 to 5 As shown, this embodiment discloses a gear and rack type steering sensor calibration fixture, including a positioning seat 1, a positioning post 2, a torque wrench 4, and a counterweight 5. The positioning seat 1 is provided with a coupling 3 for engaging with the protrusion 91 on the worm gear 9. The positioning post 2 is provided with a pressure block 21 for abutting against the steering gear housing 8. The pressure block 21 is coaxially corresponding to the coupling 3. One end of the torque wrench 4 is connected to the gear shaft 7, and the other end of the torque wrench 4 is connected to the counterweight 5. Through the engagement of the coupling 3 with the protrusion 91 of the worm gear 9 and the abutment of the pressure block 21 against the steering gear housing 8, the worm gear 9 is axially fixed, thereby indirectly fixing the gear shaft 7 (sensor body) integrated with the worm gear, avoiding sensor damage caused by direct clamping. The counterweight 5 applies a calibration torque through the torque wrench 4, achieving rapid and accurate loading of 7 Nm torque, improving calibration efficiency. The torque wrench 4 is existing technology, and the counterweight 5 is a weight.

[0021] like Figure 4 As shown, the coupling 3 includes a first connecting part 31 and a second connecting part 32 connected to the first connecting part 31. The first connecting part 31 is provided with a plurality of slots 311 spaced apart along the circumference for engaging with the protrusions 91 of the worm gear 9. The second connecting part 32 is fixedly connected to the positioning seat 1. The first connecting part 31 and the second connecting part 32 can be integrally cast. The design of multiple slots 311 ensures precise matching with the protrusions 91 of the worm gear 9 and avoids circumferential slippage.

[0022] like Figure 5As shown, the diameter of the first connecting part 31 is larger than the diameter of the second connecting part 32. The positioning seat 1 is provided with a first through hole 11 and a second through hole 12 communicating with the first through hole 11. The first connecting part 31 is located in the first through hole 11, and the groove protrudes from the first through hole 11. One end of the second connecting part 32 is located in the first through hole 11, and the other end of the second connecting part 32 is movably located in the second through hole 12. A spring 33 is provided on the outer peripheral wall of the second connecting part 32. One end of the spring 33 abuts against the bottom surface of the first connecting part 31, and the other end of the spring 33 abuts against the bottom wall of the first through hole 11. The second through hole 12 does not penetrate the positioning seat 1. The protrusion 91 of the worm gear 9 is connected to the motor. The end of the steering gear housing 8 away from the motor is closed, and the end of the steering gear housing close to the motor is open. During calibration, the protrusion 91 of the worm gear 9 and the slot 311 of the coupling 3 are engaged one-to-one. When the worm gear 9 is pressed down, the spring 33 is compressed, causing the pressure block 21 to abut against the closed end of the steering gear housing 8. The floating structure of spring 33 absorbs the axial impact force during clamping, preventing the worm gear 9 from being bumped and damaged. When the worm gear 9 is pressed, spring 33 is compressed, so that the pressure block 21 fits tightly against the closed end of the steering gear housing 8, ensuring the reliability of the fixation.

[0023] like Figure 5 As shown, the positioning seat 1 is provided with a positioning pin 13 for engaging with the groove of the steering gear housing 8. That is, the open end of the steering gear housing 8 is provided with a groove, and the steering gear housing 8 is fixed by the positioning pin 13 and the pressure block 21 to prevent the entire steering gear from shaking.

[0024] like Figure 4 and 5 As shown, the second connecting part 32 has a first plane 321 on both side walls, and the inner wall of the second through hole 12 has a second plane 121 that fits with the first plane 321. The second connecting part 32 is a cylinder with planes on both sides. The cooperation of the first plane 321 and the second plane 121 prevents the coupling 3 from rotating circumferentially, thereby avoiding rotation between the worm 9 and the worm wheel shaft and eliminating calibration errors caused by the slight rotation of the worm 9.

[0025] like Figure 1 As shown, the torque wrench 4 is equipped with an adapter sleeve, and the inner circumferential wall of the adapter sleeve is provided with a spline for meshing with the worm gear shaft. The torque wrench 4 is connected to the counterweight 5 via a connecting strap 51. One end of the torque wrench 4 is connected to the adapter sleeve, and the other end of the torque wrench 4 is provided with a hook groove 42 for connecting to the connecting strap 51. The connecting strap 51 can be an O-ring, and the hook groove 42 facilitates the direct hanging of the connecting strap 51 onto the torque wrench 4. It also includes a base plate 6, and the positioning seat 6 and the positioning post 2 are respectively installed on the top surface of the base plate 6. The torque wrench 4 acts as a rigid lever, with the adapter sleeve 41 end as the fulcrum and the hook groove 42 as the force point. The torque calculation formula is: rated torque = counterweight mass × gravitational acceleration × lever arm length, where the lever arm length is the horizontal distance from the fulcrum (center of the gear shaft) to the force point (hook part).

[0026] It is understood that the specific embodiments described above are merely for explaining the relevant utility model and not for limiting the utility model. It should also be noted that, for ease of description, only the parts related to the utility model are shown in the accompanying drawings. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not contradict or conflict with each other. All equivalent structural transformations made based on the content of this utility model specification and drawings, directly or indirectly applied to other related technical fields, are similarly included within the protection scope of this utility model.

Claims

1. A calibration fixture for a rack and pinion steering sensor, characterized in that, It includes a positioning seat, a positioning column, a torque wrench, and a counterweight. The positioning seat is provided with a coupling for engaging with a protrusion on the worm gear. The positioning column is provided with a pressure block for abutting against the steering gear housing. The pressure block is coaxially and correspondingly arranged with the coupling. One end of the torque wrench is used to connect to the gear shaft, and the other end of the torque wrench is connected to the counterweight.

2. The gear and rack type steering sensor calibration fixture according to claim 1, characterized in that, The coupling includes a first connecting part and a second connecting part connected to the first connecting part. The first connecting part is provided with a plurality of slots spaced apart along the circumference for engaging with the worm gear protrusions. The second connecting part is fixedly connected to the positioning seat.

3. The gear and rack type steering sensor calibration fixture according to claim 2, characterized in that, The diameter of the first connecting part is larger than the diameter of the second connecting part. The positioning seat is provided with a first through hole and a second through hole communicating with the first through hole. The first connecting part is located in the first through hole, and the groove protrudes from the first through hole. One end of the second connecting part is located in the first through hole, and the other end of the second connecting part is movably located in the second through hole. A spring is provided on the outer peripheral wall of the second connecting part. One end of the spring abuts against the bottom surface of the first connecting part, and the other end of the spring abuts against the bottom wall of the first through hole.

4. The gear and rack type steering sensor calibration fixture according to claim 1, characterized in that, The positioning seat is provided with a positioning pin for engaging with the groove of the steering gear housing.

5. The gear and rack type steering sensor calibration fixture according to claim 3, characterized in that, The second connecting part has a first plane on both sides, and the inner wall of the second through hole has a second plane that fits with the first plane.

6. The gear and rack type steering sensor calibration fixture according to claim 1, characterized in that, The torque wrench is equipped with an adapter sleeve, and the inner circumferential wall of the adapter sleeve is provided with a spline for engagement with the worm gear shaft.

7. The gear and rack type steering sensor calibration fixture according to claim 6, characterized in that, The torque wrench is connected to the counterweight via a connecting belt. One end of the torque wrench is connected to the adapter sleeve, and the other end of the torque wrench is provided with a hook groove that connects to the connecting belt.

8. The gear and rack type steering sensor calibration fixture according to claim 1, characterized in that, It also includes a base plate, and the positioning seat and positioning column are respectively installed on the top surface of the base plate.

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