An experimental platform for changing the interference fit between the main shaft and the bearing

Abstract

The present invention relates to the technical field of experimental equipment for high-end machine tools, and particularly to an experimental platform for changing the interference fit between a main shaft and a bearing, comprising: a main shaft, the left and middle parts of the main shaft are respectively rotationally connected to the left and right sides of the inner wall of the main shaft housing through double-row angular contact ball bearings and cylindrical roller bearings, the main shaft housing is fixedly installed on a tabletop, a plurality of inner friction plates are clamped on the outer wall of the right side of the main shaft, a plurality of outer friction plates are respectively clamped on the inner wall of the friction plate housing, the plurality of inner friction plates and the plurality of outer friction plates are alternately stacked in sequence, a magnetorheological fluid is filled in the inner cavity formed by the friction plate housing and the plurality of inner friction plates and the plurality of outer friction plates, a main shaft hole is opened at the left end of the main shaft, and paraffin wax for changing the interference fit between the main shaft and the inner ring of the double-row angular contact ball bearing by heating and expanding is filled in the main shaft hole. The present invention provides an experimental platform for changing the interference fit between a main shaft and a bearing.

Description

Technical Field

[0001] The present invention relates to the technical field of experimental equipment for high-end machine tools, and particularly to an experimental platform for changing the interference fit between a spindle and a bearing. Background Art

[0002] As an important tool for chip production, wafer slicing machine tools are continuously developing towards high speed, high efficiency, precision, light weight, and automation, making the problems of vibration and noise increasingly prominent; vibration and noise are often generated when the spindle rotates at high speed, and the main influencing factor is the interference fit between the spindle and the bearing.

[0003] Therefore, by changing the interference fit between the spindle and the bearing to obtain the influence of the change in interference fit on the operation of the spindle is of great significance for subsequent improvement of the machine tool spindle.

[0004] In the prior art, mechanical loading methods are often used to apply loads to the joint between the spindle and the bearing, which has poor flexibility and is not conducive to the analysis and research of the change amount of the interference fit. Summary of the Invention

[0005] The purpose of the present invention is to provide an experimental platform for changing the interference fit between a spindle and a bearing to solve the technical problems existing in the background art.

[0006] To achieve the above purpose, the technical solution of the present invention is as follows:

[0007] An experimental platform for changing the interference fit between a spindle and a bearing, comprising: a spindle, an inner friction plate, an outer friction plate, and a friction plate housing. The left and middle parts of the spindle are respectively rotationally connected to the left and right sides of the inner wall of the spindle housing through double-row angular contact ball bearings and cylindrical roller bearings. The spindle housing is fixedly installed on a tabletop. A plurality of inner friction plates and outer friction plates are respectively provided. A plurality of inner friction plates are clamped on the outer wall of the right side of the spindle, and a plurality of outer friction plates are respectively clamped on the inner wall of the friction plate housing. A plurality of inner friction plates and a plurality of outer friction plates are alternately stacked in sequence. The inner cavity formed by the friction plate housing and the plurality of inner friction plates and the plurality of outer friction plates is filled with magnetorheological fluid. A cavity is opened at the left end of the spindle, and the cavity is filled with paraffin wax that changes the interference fit between the spindle and the inner ring of the double-row angular contact ball bearing by heating and expanding.

[0008] Further, a frame one and a frame two are detachably and fixedly installed at the top of the tabletop. The frame one is arranged on the left side of the frame two, and the left and right sides of the outer wall of the spindle housing are respectively fixedly connected to the frame one and the frame two.

[0009] Further, it further includes a first bolt and a second bolt. There are two first bolts. The front and rear sides of the first frame are respectively fixedly installed on the desktop through the two first bolts. There are four second bolts. The front and rear sides of the second frame are respectively fixedly installed on the desktop through the four second bolts.

[0010] Further, two frame bosses are symmetrically arranged on the front and rear sides at the bottom end of the second frame. A plurality of horizontally arranged desktop grooves are evenly formed at the top end of the desktop. The desktop grooves are inverted T-shaped sliding grooves. The two frame bosses are respectively slidably connected to the two desktop grooves.

[0011] Further, a plurality of outer card slots are formed on the right side of the main shaft. A plurality of inner protrusions are arranged on the inner side of the inner friction plate. The plurality of inner protrusions are respectively clamped in the plurality of outer card slots. A plurality of inner card slots are formed on the inner wall of the friction plate housing. A plurality of outer protrusions are arranged on the outer side of the outer friction plate. The plurality of outer protrusions are respectively clamped in the plurality of inner card slots.

[0012] Further, the cavity is composed of a left cavity and a right cavity. The diameter of the left cavity is smaller than that of the right cavity. Main shaft sealing sheets are arranged on both the inner and outer sides of the left cavity. A pressure sensor is also arranged between the two main shaft sealing sheets. Paraffin is filled in the right cavity.

[0013] Further, the paraffin is connected to a power source through a wire.

[0014] Further, an end cover is sleeved on the left end of the main shaft. The end cover is detachably and fixedly installed on the left end of the main shaft housing through a plurality of fixing bolts.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. By energizing the magnetorheological fluid at one end of the main shaft to make it exhibit the characteristics of a non-Newtonian fluid, when the main shaft rotates at a high speed, the viscosity of the fluid is controlled by changing the magnitude of the applied magnetic field, so that the frictional force between the inner and outer friction plates is changed. After the motor drives the housing to rotate, flexible loading of the load and torque can be achieved. This method can simulate the influence of the cutting resistance on the dynamic stiffness of the main shaft in the actual production process.

[0017] 2. Compared with the common mechanical loading method, this experimental platform performs hydraulic loading through paraffin. When the paraffin expands due to heat, flexible loading can be achieved, which is beneficial to the analysis and research of the change amount of the interference fit; the magnitude of the applied magnetic field can also specifically reflect the load applied to the main shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural view of the present invention;

[0019] Figure 2It is a structural view of the spindle and its connecting components of the present invention;

[0020] Figure 3 It is a structural view of the internal structure of the spindle cavity of the present invention;

[0021] Figure 4 It is a schematic connection diagram of the spindle of the present invention with double-row angular contact ball bearings and cylindrical roller bearings;

[0022] Figure 5 It is a structural view of the inner and outer friction plates and the friction plate housing of the present invention;

[0023] Figure 6 It is a structural view of the second frame and the frame boss of the present invention.

[0024] The reference numerals in the figure are: 1, tabletop; 2, spindle; 2-1, inner friction plate; 2-2, outer friction plate; 2-3, magnetorheological fluid; 2-4, friction plate housing; 2-5, end cover; 2-7, spindle sealing plate; 2-8, paraffin wax; 2-9, cavity; 2-10, pressure sensor; 2-11, double-row angular contact ball bearing; 2-12, cylindrical roller bearing; 2-13, outer card slot; 3, spindle housing; 4, first frame; 5, second frame; 5-1, frame boss. Detailed implementation manners

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] Please refer to Figures 1 to 6 , an experimental platform for changing the interference fit between the spindle and the bearing, comprising: a spindle 2, an inner friction plate 2-1, an outer friction plate 2-2, and a friction plate housing 2-4. The left and middle parts of the spindle 2 are respectively rotatably connected to the left and right sides of the inner wall of the spindle housing 3 through double-row angular contact ball bearings 2-11 and cylindrical roller bearings 2-12. The spindle housing 3 is fixedly installed on the tabletop 1. A plurality of inner friction plates 2-1 and outer friction plates 2-2 are respectively provided. A plurality of inner friction plates 2-1 are clamped on the outer wall of the right side of the spindle 2, and a plurality of outer friction plates 2-2 are respectively clamped on the inner wall of the friction plate housing 2-4. A plurality of inner friction plates 2-1 and a plurality of outer friction plates 2-2 are alternately stacked in sequence. The inner cavity formed by the friction plate housing 2-4 and a plurality of inner friction plates 2-1 and a plurality of outer friction plates 2-2 is filled with a magnetorheological fluid 2-3. A cavity 2-9 is provided at the left end of the spindle, and the cavity 2-9 is filled with paraffin wax 2-8 that changes the interference fit between the spindle 2 and the inner ring of the double-row angular contact ball bearing 2-11 by heating and expanding.

[0027] A first frame 4 and a second frame 5 are detachably and fixedly installed at the top of the tabletop 1. The first frame 4 is arranged on the left side of the second frame 5. The left and right sides of the outer wall of the spindle housing 3 are respectively fixedly connected to the first frame 4 and the second frame 5, facilitating the free disassembly and assembly of the experimental platform.

[0028] It also includes a first bolt and a second bolt. There are two first bolts. The front and rear sides of the first frame 4 are respectively fixedly installed on the tabletop 1 through the two first bolts. There are four second bolts. The front and rear sides of the second frame 5 are respectively fixedly installed on the tabletop 1 through the four second bolts.

[0029] Two frame bosses 5-1 are symmetrically arranged on the front and rear sides at the bottom end of the second frame 5. A number of horizontally arranged tabletop grooves are evenly opened at the top end of the tabletop 1. The tabletop grooves are inverted T-shaped sliding grooves. The two frame bosses 5-1 are respectively slidably connected to the two tabletop grooves.

[0030] A number of outer card slots 2-13 are opened on the right side of the main shaft 2. A number of inner protrusions are arranged on the inner side of the inner friction plate 2-1. The number of inner protrusions are respectively clamped in the number of outer card slots 2-13. A number of inner card slots are opened on the inner wall of the friction plate housing 2-4. A number of outer protrusions are arranged on the outer side of the outer friction plate 2-2. The number of outer protrusions are respectively clamped in the number of inner card slots.

[0031] The cavity 2-9 is composed of a left cavity and a right cavity. The diameter of the left cavity is smaller than that of the right cavity. Main shaft sealing sheets 2-7 are arranged on both the inner and outer sides of the left cavity. A pressure sensor 2-10 is also arranged between the two main shaft sealing sheets 2-7. Paraffin 2-8 is filled in the right cavity.

[0032] The paraffin 2-8 is connected to a power supply through a wire. When powered on, the paraffin expands to apply a load to the joint of the main shaft 2 and the angular contact ball bearing 2-11; the pressure sensor 2-10 is a device for signal reception and transmission.

[0033] An end cover 2-5 is sleeved on the left end of the main shaft 2. The end cover 2-5 is detachably and fixedly installed on the left end of the main shaft housing 3 through a number of fixing bolts.

[0034] The working process of this experimental platform: Fix the motor bracket on the tabletop with screws. The motor is connected to the coupling through a spline, and the coupling is connected to the main shaft 2. The motor drives the main shaft 2 to rotate; since a cavity 2-9 is opened at the left end of the main shaft, the cavity 2-9 is composed of a left cavity and a right cavity. The diameter of the left cavity is smaller than that of the right cavity. Main shaft sealing sheets 2-7 are arranged on both the inner and outer sides of the left cavity. A pressure sensor 2-10 is also arranged between the two main shaft sealing sheets 2-7. Paraffin 2-8 is filled in the right cavity. Power on the paraffin 2-8. The paraffin expands to exert a force on the surrounding, changing the interference fit degree between the main shaft 2 and the inner ring of the angular contact ball bearing 2-11; measure and transmit data on the magnitude of the generated force and the change in the interference amount through the pressure sensor 2-10 inside the main shaft 2.

[0035] The physical characteristic parameters of the paraffin material are as follows:

[0036] The density is: 760 kg / m 3 ; Specific heat: 2100 kg / (k*kg); Latent heat of phase change: 170 kJ / kg; Liquid phase temperature: 330.15 K; Dynamic viscosity: 0.0032 kg / (m*s); Thermal conductivity: 0.25 W / (m*k).

[0037] According to the parameters, a cavity of appropriate size is opened in the main shaft for filling paraffin through calculation, and the design of the scheme is verified through the ansys simulation software.

[0038] Since the inner ring of the double-row angular contact ball bearing and the main shaft are in interference fit, d2 = d'.

[0039] The compressive stress δ1 generated by the inner ring of the double-row angular contact ball bearing on the surface of the main shaft is:[[]]

[0040]

[0041] Also according to

[0042]

[0043] d - Inner diameter of the bearing before assembly, mm; d' - Actual diameter of the shaft after assembly, mm

[0044] d1 - Diameter of the shaft before assembly, mm; d2 - Actual diameter of the shaft after assembly, mm

[0045] E1 - Elastic modulus of the inner ring, MPa; E2 - Elastic modulus of the shaft, MPa

[0046] H1 - Wall thickness of the inner ring before assembly, mm; H2 - Wall thickness of the inner ring after assembly, mm

[0047] v - Poisson's ratio

[0048] Through equations (1), (2), and (3), the stresses inside the main shaft and the inner ring of the double-row angular contact ball bearing after interference fit can be calculated, thereby evaluating the influence of the interference fit between the main shaft and the inner ring of the double-row angular contact ball bearing on the performance of the main shaft and the double-row angular contact ball bearing. It is also possible to measure the amount of expansion of the inner ring raceway after interference assembly of the main shaft and the inner ring of the double-row angular contact ball bearing, take D as the known value, calculate the value of d through equations (2) and (3), compare it with the measured value of d1, and use the difference as the interference amount correction value, thereby simulating and analyzing the influence of the interference fit amount between the main shaft 2 and the double-row angular contact ball bearing 2-11 on the dynamic stiffness of the main shaft 2;

[0049] Next, an electric current is applied to the magnetorheological fluid at one end of the main shaft 2 to make it exhibit the characteristics of a non-Newtonian fluid. When the main shaft 2 rotates at a high speed, the viscosity of the fluid is controlled by changing the magnitude of the applied magnetic field, thereby changing the frictional force between the inner and outer friction plates. A shaft extends out of the friction plate housing 2-4 and is installed in a damping bearing on the bracket to simulate the resistance suffered by the main shaft during high-speed rotation; the damping bearing bracket is fixed in the table slot by bolts. After the motor drives the friction plate housing 2-4 to rotate, flexible loading of the load and torque can be achieved. This method can simulate the influence of the cutting resistance on the dynamic stiffness of the main shaft in the actual production process.

[0050] The above is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. Any person skilled in the relevant art, without departing from the scope of the technical solution of the present invention and based on the technical essence of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments still fall within the protection scope of the technical solution of the present invention.

Claims

1. An experimental platform for changing the interference fit between the main shaft and the bearing, characterized in that, Including: A main shaft (2), inner friction plates (2-1), outer friction plates (2-2) and a friction plate housing (2-4). The left side of the main shaft (2) is rotatably connected to the left side of the inner wall of the main shaft housing (3) through a double-row angular contact ball bearing (2-11). The middle of the main shaft (2) is rotatably connected to the right side of the inner wall of the main shaft housing (3) through a cylindrical roller bearing (2-12). The main shaft housing (3) is fixedly installed on the tabletop (1). A number of inner friction plates (2-1) and outer friction plates (2-2) are respectively provided. A number of inner friction plates (2-1) are clamped on the outer wall of the right side of the main shaft (2). A number of outer friction plates (2-2) are respectively clamped on the inner wall of the friction plate housing (2-4). A number of inner friction plates (2-1) and a number of outer friction plates (2-2) are alternately stacked in sequence. The inner cavity formed by the friction plate housing (2-4) and a number of inner friction plates (2-1) and a number of outer friction plates (2-2) is filled with magnetorheological fluid (2-3). A cavity (2-9) is provided at the left end of the main shaft. Paraffin wax (2-8) which changes the interference fit degree between the main shaft (2) and the inner ring of the double-row angular contact ball bearing (2-11) by heating and expanding is filled inside the cavity (2-9).

2. The experimental platform for changing the interference fit between the main shaft and the bearing according to claim 1, characterized in that: A frame one (4) and a frame two (5) are detachably and fixedly installed at the top of the tabletop (1). The frame one (4) is arranged on the left side of the frame two (5). The left and right sides of the outer wall of the main shaft housing (3) are respectively fixedly connected to the frame one (4) and the frame two (5).

3. An experimental platform for changing the interference fit between the main shaft and the bearing according to claim 2, characterized in that: It also includes a first bolt and a second bolt. There are two first bolts. The front and rear sides of the frame one (4) are respectively fixedly installed on the tabletop (1) through the two first bolts. There are four second bolts. The front and rear sides of the frame two (5) are respectively fixedly installed on the tabletop (1) through the four second bolts.

4. An experimental platform for changing the interference fit between the main shaft and the bearing according to claim 3, characterized in that: Two frame bosses (5-2) are symmetrically arranged at the front and rear sides of the bottom end of the frame two (5). A number of horizontally arranged tabletop grooves are evenly opened at the top of the tabletop (1). The tabletop grooves are inverted T-shaped sliding grooves. The two frame bosses (5-2) are respectively slidably connected to the two tabletop grooves.

5. An experimental platform for changing the interference fit between the main shaft and the bearing according to claim 1, characterized in that: A number of outer card slots (2-13) are provided on the right side of the main shaft (2). A number of inner protrusions are provided on the inner side of the inner friction plate (2-1). The number of inner protrusions are respectively clamped in the number of outer card slots (2-13). A number of inner card slots are opened on the inner wall of the friction plate housing (2-4). A number of outer protrusions are provided on the outer side of the outer friction plate (2-2). The number of outer protrusions are respectively clamped in the number of inner card slots.

6. An experimental platform for changing the interference between the main shaft and the bearing according to claim 1, characterized in that: The cavity (2-9) is composed of a left cavity and a right cavity. The diameter of the left cavity is smaller than that of the right cavity. Main shaft sealing sheets (2-7) are arranged on both the inner and outer sides of the left cavity. A pressure sensor (2-10) is also arranged between the two main shaft sealing sheets (2-7). Paraffin wax (2-8) is filled in the right cavity.

7. An experimental platform for changing the interference fit between the main shaft and the bearing according to claim 1 or 6, characterized in that: The paraffin wax (2-8) is connected to a power source through a wire.

8. An experimental platform for changing the interference between the main shaft and the bearing according to claim 1, characterized in that: A end cover (2-5) is sleeved on the left end of the main shaft (2), and the end cover (2-5) is detachably and fixedly installed on the left end of the main shaft housing (3) through a plurality of fixing bolts.

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