Equipment and method for testing interference friction force and hydraulic locking force of composite roller

Abstract

The invention relates to equipment and a method for testing interference friction force and hydraulic locking force of a composite roller, and belongs to the technical field of composite roller testing. The testing equipment comprises a shaft core and an inner supporting expansion mechanism, the shaft core is hollow and is provided with shaft core sections with different diameters and is hollowed out, the inner supporting expansion mechanism comprises a lead screw, a plurality of outer supporting strips and a connecting rod supporting structure connected with the outer supporting strips and the lead screw, and the lead screw drives the outer supporting strips to move in the radial direction to be in interference fit with a roll collar to be tested. A first pressure sensor is arranged to measure contact pressure, and a second pressure sensor is arranged to measure locking force applied to a plurality of positions. According to the invention, the interference magnitude is accurately controlled and pressure data is collected through the inner support expansion mechanism, the interference friction force and hydraulic locking force transmission effect of the composite roller under different interference magnitudes can be accurately detected, and reliable test data is provided for the design of the composite roller.

Description

Technical Field

[0001] The present invention relates to the technical field of composite roller testing, and in particular to a composite roller interference friction force and hydraulic locking force testing device and method. Background Art

[0002] Composite rolls are rolls whose shafts and rings are made of different materials and are widely used in rebar rolling processes. To improve rolling efficiency, some composite rolls have multiple rings, with spacer rings installed between each ring and on adjacent sides. Hydraulic nuts are used to axially lock the rings. Slippage between the rings and the shaft is a problem that must be avoided in the design and manufacture of composite rolls. This problem occurs due to two factors: insufficient friction caused by the interference fit between the rings and the shaft; and insufficient friction caused by the axial locking force of the hydraulic nut acting on the end faces of the rings, which hinders their rotation.

[0003] Therefore, there is an urgent need for a testing device that can measure the friction force that actually hinders the forward and backward movement of the roller ring caused by different interference fits between the roller ring and the roller shaft, as well as the axial locking force after being transmitted through each layer of roller rings and spacer rings. Summary of the Invention

[0004] In response to the above problems, the present invention provides a composite roller interference friction force and hydraulic locking force testing device and method.

[0005] The technical solution to solve the above technical problems is as follows: a composite roller interference friction and hydraulic locking force testing device, the composite roller includes a roller ring to be tested and a hydraulic nut to be tested, characterized in that the testing device includes a shaft core and an internal support expansion mechanism; the shaft core includes a first shaft core segment with a larger outer diameter and a second shaft core segment with a smaller outer diameter, an inner hole for installing the internal support expansion mechanism is provided inside, and the second shaft core segment is provided with a strip-shaped hollow; the roller ring to be tested is sleeved on the second shaft core segment and is adjacent to the end of the first shaft core segment, and the hydraulic nut to be tested is used to apply axial locking force to the roller ring to be tested; the internal support expansion mechanism includes a screw rod, a plurality of outer support bars and a connecting rod support structure connecting the outer support bars and the screw rod, the outer support bars, the screw rod and the shaft core are arranged in parallel, and the connecting rod support structure is used to radially move the outer support bar connected to it through the strip-shaped hollow as the screw rod rotates forward or reverse; a first pressure sensor is provided on the surface of the outer support bar in contact with the roller ring to be tested, and a second pressure sensor is provided between the roller ring and the first shaft core segment and the locking nut.

[0006] During the test, the outer support bar is driven to open by rotating the screw rod, and the outer support bar forms an interference fit with the roller ring to be tested. The contact pressure is measured by the first pressure sensor, and the locking force at different positions is measured by the second pressure sensor.

[0007] Preferably, the testing equipment also includes at least one test spacer ring, the number of which is equal to the number of roller rings to be tested. The test spacer ring is mounted on the second shaft core segment and is located between the roller ring to be tested and the hydraulic nut to be tested or between two adjacent roller rings to be tested. The test spacer ring is used to simulate the spacer ring arrangement in the actual composite roller structure.

[0008] Preferably, the second pressure sensor is an annular pressure sensor, which is specifically located between the test spacer ring and the roller ring to be tested, and between the test spacer ring and the hydraulic nut to be tested; the end faces of the test spacer ring and the first shaft core segment are both provided with annular grooves for installing the annular pressure sensor; the annular pressure sensor can accurately measure the transmission value of the locking force applied to each layer of the annular structure.

[0009] Preferably, the first pressure sensor is a patch pressure sensor, which protrudes from the surface of the outer support bar. The surface of the patch pressure sensor is an arc surface that matches the curvature of the inner hole of the roller ring to be measured; the arc surface design ensures complete fit with the inner wall of the roller ring, increasing the effective contact area.

[0010] Preferably, the connecting rod support structure includes a fixed nut, a movable nut and a support rod, the fixed nut is fixedly connected to the screw rod, the movable nut is threadedly connected to the screw rod, one end of the support rod is hinged to the movable nut or the fixed nut, and the other end is hinged to the external support bar; this structure realizes the conversion between the rotational motion of the screw rod and the radial motion of the outer support bar.

[0011] Preferably, the internal support expansion mechanism has 2N connecting rod support structures, and each N connecting rod support structures are evenly distributed circumferentially on the screw rod; the screw rod is provided with two sections of threads, and each section of threads drives N connecting rod support structures; the uniform arrangement of multiple connecting rod support structures can ensure that the roller ring to be tested is uniformly stressed.

[0012] Preferably, the screw is driven by a servo motor, and the servo motor can accurately control the rotation angle of the screw.

[0013] Preferably, an annular groove is provided at one end of the inner hole of the shaft core, and a fixing plug is provided at the other end. The fixing plug is provided with an inner hole with an annular groove. Positioning steps are provided at one end of the screw rod and the middle part of the screw rod, and axial fixation is achieved by matching the bearing with the annular groove of the inner hole of the shaft core; the two axial fixing structures ensure the rotation stability of the screw rod.

[0014] Preferably, a wireless transmission module box is provided on the side of the outer support bar for transmitting the data collected by the first pressure sensor to the outside. The wireless transmission method can also avoid cable entanglement during rotation.

[0015] In a second aspect, the present invention further proposes a method for testing the interference friction force and hydraulic locking force of a composite roller, which is implemented using the above-mentioned testing equipment.

[0016] The present invention provides a radially adjustable inner support expansion mechanism, and cooperates with two types of pressure sensors, patch type and annular type, to accurately measure the interference friction force and the transmission of hydraulic locking force under different interference amounts. The equipment has a reasonable structure and the test data is accurate and reliable, providing a research basis for the interference amount design of the composite roller. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A cross-sectional view of a composite roller interference friction force and hydraulic locking force testing device according to the present invention; Figure 2 It is a structural schematic diagram of the shaft core equipped with the internal support expansion mechanism in the testing equipment of the present invention; Figure 3 It is a structural schematic diagram of the internal support expansion mechanism in the testing equipment of the present invention.

[0018] Figure markings: 1-shaft core, 2-internal support expansion mechanism, 3-roller ring to be tested, 4-test spacer ring, 5-locking nut to be tested, 6-several annular pressure sensors, 7-bearing, 201-servo motor, 202-screw rod, 203-connecting rod support structure, 204-external support bar, 205-patch type pressure sensor, 206-wireless transmission module box, 207-reducer, 203a-first support rod, 203b-second support rod, 203c-fixing nut, 203d-moving nut. DETAILED DESCRIPTION

[0019] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0020] The composite roller to be tested consists of a roller shaft, roller ring, spacer ring, and lock nut. The roller ring and spacer ring are mounted in the middle of the roller shaft. A raised step with a diameter comparable to the roller ring is located off-center in the middle of the roller shaft. The lock nut presses the roller ring and spacer ring against one side of the raised step on the roller shaft. The roller ring and the roller shaft have an interference fit, and the roller ring is typically made of hard alloy. Because cemented carbide is more brittle than steel, excessive interference fit increases the risk of the carbide composite roller ring breaking during use. If the interference fit is too small, the locking force of the hydraulic nut is completely relied upon to secure the roller ring and shaft relative to each other, increasing the risk of the roller ring spinning during use. Proper interference fit is crucial to composite roller design.

[0021] The forces that ensure that there is no relative movement between the roller shaft and the roller ring include two aspects: one is the friction force formed by the interference extrusion between the roller ring and the roller shaft (hereinafter referred to as interference friction force); the other is the friction force formed by the axial locking force of the hydraulic nut acting on the end face of the roller ring to hinder the rotation of the roller ring.

[0022] The size of the interference friction force is affected by various factors such as the roller ring inner hole specifications, wall thickness, inner hole roundness, straightness, roller ring end face parallelism and inner hole roughness, and is difficult to calculate using conventional modeling methods.

[0023] The axial locking force of the hydraulic nut must be greater than the interference friction between all roller rings and spacer rings and the roller shaft for the following reasons. During the assembly of the composite roller, the roller rings and the roller shaft are hot-fitted, that is, the roller rings are heated to expand their inner holes before being inserted into the roller shaft. After cooling to room temperature, an interference fit is formed. This method will cause a gap to appear between the roller rings and the spacer rings. Therefore, the hydraulic pressure of the hydraulic nut is required to push the roller rings to the bottom, eliminating the gap after cooling, while giving the roller rings and spacer rings a certain axial locking force. This axial locking force is transmitted through layers of roller rings and spacer rings to the protruding step end face of the roller shaft. During the transmission of the axial locking force, the interference friction will gradually weaken the axial locking force. Once the axial locking force is less than the interference friction, the force transmission of the hydraulic nut will be interrupted, and there is a high probability that the roller rings will slip and rotate in subsequent use.

[0024] In order to test the actual interference friction force generated by different interference amounts and the axial locking force after being transmitted through each layer of roller rings and spacer rings, this embodiment proposes a composite roller interference friction force and hydraulic locking force testing device, such as Figure 1 As shown, it includes: a shaft core 1, an internal support expansion mechanism 2, a roller ring to be tested 3, a test spacer ring 4, a locking nut to be tested 5, and an annular pressure sensor 6.

[0025] like Figure 2 As shown, the shaft core 1 has a stepped shaft structure, comprising a first shaft core section with a larger outer diameter and a second shaft core section with a smaller outer diameter. The first shaft core section, the roller ring of the composite roller to be tested (hereinafter referred to as the roller ring 3 to be tested), the test spacer ring 4, and the hydraulic nut of the composite roller to be tested (hereinafter referred to as the locking nut 5 to be tested) have the same outer diameter. The roller ring 3 to be tested, the test spacer ring 4, and the locking nut 5 to be tested are mounted on the second shaft core section. The locking nut 5 to be tested is threadedly connected to the shaft core 1. When tightened, the locking nut 5 to be tested provides an axial locking force, pressing the roller ring 3 to be tested and the test spacer ring 4 to the end face of the first shaft core section. Annular pressure sensors 6 are installed between the roller ring 3 to be tested and the test spacer ring 4, between the roller ring 3 to be tested and the first shaft core section, and between the test spacer ring 4 and the locking nut 5 to be tested. These sensors are used to measure the hydraulic locking force at different positions. Grooves for mounting the annular pressure sensors 6 are provided on the end faces of the first shaft core section and the test spacer ring 4. The interior of the shaft core 1 is hollow and has an axial inner hole. The second shaft core segment has circumferentially distributed strip-shaped hollows that are connected to the axial inner hole. The extension direction of the strip-shaped hollows is parallel to the axial direction of the shaft core 1, and the width of the strip-shaped hollows is adapted to the width of the outer support bar 204.

[0026] like Figure 3As shown, the internal support expansion mechanism 2 includes a servo motor 201, a screw rod 202, a connecting rod support structure 203 and an external support bar 204. The servo motor 201 is arranged at one end of the screw rod 202, and is used to drive the screw rod 202 to rotate forward or reverse. This end of the screw rod 202 is the driving end. The screw rod 202 penetrates the inner hole of the shaft core 1. The other end of the screw rod 202 is axially fixed inside the shaft core 1, and this end is the fixed end. A protruding positioning step is provided at the fixed end and near the driving end of the screw rod 202. The outer sleeve of the positioning step is provided with a bearing 7. The inner hole of the shaft core 1 is processed with an annular groove at the corresponding position of the positioning step at the fixed end of the screw rod 202. The positioning step at the fixed end of the screw rod 202 is installed in the annular groove of the inner hole of the shaft core 1 through the bearing 7 to achieve axial fixation. A fixing plug is provided at the inner hole of the shaft core 1 near the motor end. The fixing plug fixes the screw rod 202 axially through the bearing. The two axial fixing points can ensure that the screw rod 202 is coaxial with the shaft core 1, reducing the offset during rotation. Screw rod 202 is machined with two sections of external thread, with no thread between the two sections. Internal support expansion mechanism 2 also includes a reducer 207, installed between servo motor 201 and screw rod 202. Its input is connected to the output shaft of servo motor 201, and its output is connected to screw rod 202. The provision of reducer 207 allows for more precise adjustment of the outward extension of outer support bar 204.

[0027] The connecting rod support structure 203 consists of a first support rod 203a, a second support rod 203b, a fixed nut 203c, and a movable nut 203d. One end of the first support rod 203a is hinged to the movable nut 203d, and the other end is hinged to the outer support bar 204. The second support rod 203b is hinged to the fixed nut 203c at one end, and the other end is hinged to the outer support bar 204. There are eight connecting rod support structures 203, each group of four evenly distributed around the circumference of one section of the external thread of the screw rod 202. The same set of connecting rod support structures 203 is provided on each of the two sections of the external thread. The fixed nut 203c and the movable nut 203d are sleeved onto the screw rod 202, with the fixed nut 203c fixed to the screw rod 202 and the movable nut 203d threadedly connected to the screw rod 202. The two sections of the external thread have the same helical direction, and the two movable nuts 203d have the same helical direction. There are four outer support bars 204, and two connecting rod support structures 203 with two sections of external threads and the same axis are connected to one outer support bar 204. The screw rod 202 is also equipped with four additional fixing nuts 203c and four support rods evenly distributed around the circumference. One end of each support rod is hinged to the fixing nut 203c, and the other end is hinged to the outer support bar 204 to enhance the stability of the outer support bar 204.

[0028] When the servo motor 201 drives the screw rod 202 to rotate, all the movable nuts 203d move synchronously, driving the outer support bars 204 connected thereto to extend outward or retract inward through the first support rod 203a and the second support rod 203b. When the multiple outer support bars 204 extend outward, they form an interference fit with the roller ring 3 to be tested and the test spacer ring 4. Several patch-type pressure sensors 205 are provided on the surface of the outer support bar 204. The surface of the patch-type pressure sensor 205 is curved, matching the curvature of the inner hole of the roller ring 3 to be tested. Each pressure sensor protrudes from the surface of the outer support bar 204 and contacts the roller ring to measure the pressure between the outer support bar 204 and the roller ring 3 to be tested or the test spacer ring 4. A wireless transmission module box 206 is provided on the side of the outer support bar 204. The wireless transmission module box 206 has its own power supply and transmits the pressure data measured by the patch-type pressure sensor 205 to the outside.

[0029] Based on the above-mentioned composite roller interference friction force and hydraulic locking force testing equipment, this embodiment further proposes the following testing method.

[0030] S1: Assemble the roller ring 3 to be tested, the test spacer ring 4 and the locking nut 5 to be tested on the shaft core 1, and install the annular pressure sensor 6.

[0031] S2: Input a pulse signal to the servo motor 201, which drives the screw 202 to rotate. The outer support bar 204 is stretched outward through the hollowed-out portion of the shaft core 1 to form an interference fit with the roller ring 3 to be tested / the test spacer ring 4.

[0032] S3: The pressure between the outer support bar 204 and the roller ring 3 to be tested / test spacer ring 4 is measured by the patch pressure sensor 205 on the outer support bar 204. The interference friction force is calculated based on the pressure measured by the patch pressure sensor 205. The calculation formula is: in, Indicates the interference friction force, Indicates the sliding friction coefficient between the inner wall of the roller ring and the patch pressure sensor, Indicates the effective contact area between each patch pressure sensor and the inner wall of the roller ring, Represents the pressure measured by the i-th patch pressure sensor.

[0033] S4: Repeat S2-S3, change the number of pulses of the pulse signal, so that the interference between the outer support bar 204 and the roller ring 3 to be tested / test spacer ring 4 changes, and measure the interference friction under different interference amounts. The interference amount can be calculated based on the pulse signal, the lead of the screw rod 202 and the mechanical structure of the internal support expansion mechanism 2.

[0034] S5: Use a press to press the locking nut 5 to generate an axial locking force, and use an annular pressure sensor 6 to measure the axial locking force of the locking nut 5 after passing through multiple roller rings and spacer rings.

[0035] The interference friction force and the axial locking force of each layer structure measured by the above method are highly efficient, simple to operate, and close to the actual situation. They have excellent reference value for the interference design of the composite roller.

[0036] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A composite roller interference friction and hydraulic locking force testing device, the composite roller comprising a roller ring to be tested and a hydraulic nut to be tested, characterized in that: The testing equipment includes an axis core and an internal support expansion mechanism; the axis core includes a first axis core segment with a larger outer diameter and a second axis core segment with a smaller outer diameter, an inner hole for installing the internal support expansion mechanism is provided inside, and the second axis core segment is provided with a strip-shaped hollow; the roller ring to be tested is mounted on the second axis core segment of the shaft and is adjacent to the end of the first axis core segment, and the hydraulic nut to be tested is used to apply axial locking force to the roller ring to be tested; the internal support expansion mechanism includes a screw rod, a plurality of external support bars and a connecting rod support structure connecting the external support bars and the screw rod, the external support bars, the screw rod and the axis core are arranged in parallel, and the connecting rod support structure is used to radially move the external support bar connected to it through the strip-shaped hollow as the screw rod rotates forward or reverse; the surface of the external support bar in contact with the roller ring to be tested is provided with a first pressure sensor, and a second pressure sensor is provided between the roller ring and the first axis core segment and the locking nut.

2. The testing device according to claim 1, characterized in that The testing equipment also includes at least one test spacer ring, the number of which is equal to the number of roller rings to be tested. The test spacer ring is sleeved on the second shaft core segment and is located between the roller ring to be tested and the hydraulic nut to be tested or between two adjacent roller rings to be tested.

3. The testing device according to claim 2, characterized in that The second pressure sensor is an annular pressure sensor, specifically located between the test spacer ring and the roller ring to be tested, and between the test spacer ring and the hydraulic nut to be tested; the end faces of the test spacer ring and the first shaft core segment are both provided with annular grooves for installing the annular pressure sensor.

4. The testing device according to claim 1, wherein: The first pressure sensor is a patch pressure sensor, which protrudes from the surface of the outer support bar. The surface of the patch pressure sensor is an arc surface that matches the curvature of the inner hole of the roller ring to be measured.

5. The testing device according to claim 1, characterized in that The connecting rod support structure includes a fixed nut, a movable nut and a support rod. The fixed nut is fixedly connected to the screw rod, and the movable nut is threadedly connected to the screw rod. One end of the support rod is hinged to the movable nut or the fixed nut, and the other end is hinged to the external support bar.

6. The testing device according to claim 1, wherein: The internal support expansion mechanism has 2N connecting rod support structures, and each N connecting rod support structures are evenly distributed on the screw rod in the circumferential direction; the screw rod is provided with two sections of threads, and each section of threads drives N connecting rod support structures.

7. The testing device according to claim 1, characterized in that The screw rod is driven by a servo motor.

8. The testing device according to claim 1, wherein: One end of the inner hole of the shaft core is provided with an annular groove, and the other end is provided with a fixing plug. The fixing plug is provided with an inner hole with an annular groove. One end of the screw rod and the middle part of the screw rod are respectively provided with positioning steps, and axial fixation is achieved by matching the bearing with the annular groove of the inner hole of the shaft core.

9. The testing device according to claim 1, characterized in that A wireless transmission module box is provided on the side of the outer support bar for transmitting data collected by the first pressure sensor to the outside.

10. A method for testing the interference friction and hydraulic locking force of a composite roller based on the testing equipment according to claims 1-9, characterized in that: The following steps are involved: S1: Install the roller ring and hydraulic nut to be tested on the second shaft section of the shaft core; S2: Rotate the screw rod to drive the outer support bar to prop up outward through the connecting rod support structure, forming an interference fit with the roller ring to be tested; S3: collecting pressure data through the first pressure sensors on the outer support bar, and calculating the interference friction force based on the pressure data collected by all the first pressure sensors; S4: Adjust the rotation angle of the screw and change the radial displacement of the outer support bar to obtain different interferences. Repeat S2-S3 to collect the interference friction under different interferences. S4: Pressurize the hydraulic nut to be tested to a predetermined hydraulic pressure, so that the hydraulic nut to be tested applies an axial locking force to the roller ring, and measure the locking force data at different positions through the annular pressure sensor.

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