Hydrostatic bearing with magnetic control and braking effect

Abstract

The invention relates to a hydrostatic bearing creating a braking effect by changing the resistance to flow of a magnetic-rheological property fluid passed through a narrow channel (6) where bearing takes place, by means of an applied magnetic field with a coil (7) placed on the shaft (5).

Description

[0001] DESCRIPTION

[0002] HYDROSTATIC BEARING WITH MAGNETIC CONTROL AND BRAKING

[0003] EFFECT

[0004] Technical Field

[0005] The invention relates to a hydrostatic bearing creating a braking effect by changing the resistance to flow of a magnetic-rheological property fluid passed through a narrow channel where bearing takes place, by means of an applied magnetic field with a coil placed on the shaft.

[0006] Prior Art

[0007] A film created by an externally pressurized fluid exists between surfaces in relative motion. These bearings are named as hydrostatic if the fluid is incompressible, and as aerostatic bearings if it is compressible. In these bearing systems, a device to provide pressurized fluid is always required. Bearings to support radial and axial loads must be designed separately.

[0008] The fluid pumped at a constant supply pressure passes through an orifice which causes its pressure to decrease, and separates the two surfaces from each other by forming a high-pressure fluid film. In this way, bearing takes place between these two surfaces. In this bearing system, the changing of the bearing stiffness can be achieved depending on the changed supply pressure for control. Magnetorheological fluids, on the other hand, are fluids containing particles that are magnetized at the micron level. Fluid particles activated in a narrow passage channel by an externally applied magnetic field create a resistance against the fluid flow. Thanks to the changed magnetic field intensity, they enable the control of the devices in which they are used.

[0009] In hydrostatic bearings, bearing stiffness can be achieved with high supply pressure. Due to this high pressure, oil leakages may occur, which decreases system efficiency and creates a need for additional maintenance. Furthermore, the desired bearing stiffness can be achieved by changing the supply pressure and flow rate via a pump and / or control valve. In this case, a control algorithm connected to the pumping system is required to be operated depending on the requirement of the system to which the bearing will be connected. However, since the system can be adjusted with a mechanical change in this way, the inability to respond quickly to sudden load changes can cause performance losses and contact wear. The thickness of this high- pressure oil film (an extremely small hydraulic diameter) requires high precision. Therefore, precise control systems are required. The very small hydraulic diameter of this high-pressure oil film requires high precision and this precision becomes even more critical when the mechanism approaches its upper and lower motion limits. Here, it is extremely important to assist in the deceleration (and eventually stopping) of the motion mechanism while also providing the desired bearing. However, in existing systems, hydraulic oil cannot be used in this way with bearing.

[0010] In the document titled “Study on MR fluid hybrid hole-entry spherical journal bearing with micro-grooves, performance analysis of textured spherical hybrid journal bearings operated with magnetorheological fluid”, they examined the effect of this by using magnetorheological fluid in spherical hybrid journal bearings having textured surfaces in the form of circular, rectangular, and conical shapes. It shows with numerical simulations that the application of these textured surfaces and MR fluid improves the minimum fluid film thickness and the stability values of the bearing. Unlike the presented patent, in this study, a spherical bearing was used, and they examined the bearing with magnetorheological fluid using different textures on the bearing surface.

[0011] In the document titled “Design and simulation of hydrostatic bearings lubricated with magnetorheological fluid”, they proposed a type of hydrostatic bearing lubricated with magnetorheological fluid to improve the capacity and rotation accuracy of the hydrostatic bearing. By calculating the effects of different bearing materials and different currents on the performance of the hydrostatic bearing with flow and magnetic field simulations, the designed magnetorheological hydrostatic bearing was improved by 11.6% in its capacity and by 17.4% in its rotation accuracy compared to an ordinary hydrostatic bearing.

[0012] In the document numbered CN114135582A, a design has been made in which the magnetic effect is created only on the holes entering the bearing with supply pressure. The design proposed here is different from this patent because the magnetic effect will be effective both on the flow film thickness and on the hole where the supply pressure enters.

[0013] In the document numbered CN108612757A, permanent magnets and 4 enameled coils were used. By placing the permanent magnets just above the shaft surface and below the bearing film, the fluid was subjected to the magnetic effect in this way. However, in the design proposed here, an electromagnetic coil is located on the shaft surface, and the keeping of the fluid under magnetic effect even when the permanent magnet is not necessary has been prevented. In the document numbered CN108331837A, the fluid was magnetized with 2 permanent magnets (17, 20) and 8 enameled coils (14). Unlike the design proposed here, the fluid was magnetized only at the bearing film outlet.

[0014] In the document numbered CN108612753A, the fluid was magnetized with permanent magnets and enameled coils. Unlike the design proposed here, the fluid was magnetized only at the bearing film outlet.

[0015] The document titled “Experimental results on a hydrostatic bearing lubricated with a magnetorheological fluid”, discloses a hydrostatic bearing in which the pressure profile of a conventional hydrostatic bearing is reconstructed using a magnetic field and a magnetorheological fluid.

[0016] The document numbered CN115899082A, discloses a bearing developed using a hydrostatic bearing lubricated with magnetorheological fluid and a coil, and its effectiveness.

[0017] When the studies existing in the prior art are examined, a need has been felt for the development of a magnetic control and braking effect hydrostatic bearing.

[0018] Objectives of the Invention

[0019] The object of this invention is to develop a hydrostatic bearing creating a braking effect by changing the resistance to flow of a magnetic-rheological property fluid passed through a narrow flow channel where bearing takes place, by means of an applied magnetic field with a coil placed on the shaft.

[0020] Another object of this invention is to develop the provision of both the ability to perform the control of the bearing stiffness quickly and effectively, and the provision of braking control of the motion mechanism of the system to which the bearing is connected, using a magnetorheological fluid in the hydrostatic bearing and thanks to the high magnetic effect.

[0021] Detailed Description of the Invention

[0022] The hydrostatic bearing with magnetic control and braking effect implemented to achieve the objects of this invention is shown in the attached figures. Figure 1 A perspective cross-sectional view of the magnetic control and braking effect hydrostatic bearing subject to the invention.

[0023] Figure 2 A cross-sectional view of the magnetic control and braking effect hydrostatic bearing subject to the invention.

[0024] Figure 3 An exploded cross-sectional view of the magnetic control and braking effect hydrostatic bearing subject to the invention.

[0025] Figure 4 An exploded view of the magnetic control and braking effect hydrostatic bearing subject to the invention.

[0026] The parts located in the figures are individually numbered, and the counterparts of these numbers are given below.

[0027] 1. Body

[0028] 2. Inlet port

[0029] 3. Orifice

[0030] 4. Recess

[0031] 5. Shaft

[0032] 6. Narrow channel

[0033] 7. Coil

[0034] A hydrostatic bearing with magnetic control and braking effect, and comprises: a bearing body (1), an inlet port (2) opened from the upper surface of the body (1) towards the inside of the body (1) and enabling the fluid to enter by circulating around the entire body (1), a pressure-reducing orifice (3) enabling the fluid inside the inlet port (2) to enter the bearing surface, a recess (4) located at the outlet of the orifice (3) and in the inner part of the body (1), a shaft (5) located inside the body (1), a narrow channel (6) opened between the body (1) and the shaft (5), an electromagnetic coil (7) placed on the shaft (5). The inlet port (2) enables the fluid to enter into the body via a certain number of orifices (3) by circulating around the entire body.

[0035] The recess (4) prevents backflow and creates a constant pressure gradient under high bearing loads that may be encountered.

[0036] The narrow channel (6) provides the bearing in its fluid-filled state by separating the surfaces of the body (1) and the shaft (5) from each other.

[0037] The electromagnetic coil (7) enables bearing and braking control by being placed on the shaft (5) and by creating a magnetic field on the hydraulic fluid with magnetorheological properties.

[0038] In an embodiment of the subject invention; the hydraulic fluid with magnetorheological properties is pumped towards the inside of the body (1) from the inlet port (2) on a hydrostatic journal bearing body (1) with a constant supply pressure. The hydraulic fluid with magnetorheological properties passes through a orifice (3) which causes the pressure to decrease, and reaches the recess (4) section, which is relatively deeper compared to the narrow channel (6) found between the body (1) and the shaft (5). The pressure within the volume of the recess (4) is at a constant value smaller than the supply pressure, and it prevents backflow from the bearing under high bearing loads encountered. Bearing is achieved by maintaining a pressurized narrow channel (6) that separates the surfaces of the body (1) and the shaft (5). The pressure inside the narrow channel (6) decreases while the hydraulic fluid with magnetorheological properties flows towards the outlet and reaches the ambient pressure at the outlet. The electromagnetic coil (7) placed on the shaft (5) is wound into a certain volume around the axis of the shaft (5). A magnetic field is created between the body (1) and the shaft (5) with an electric current applied to the electromagnetic coil (7); by design, this magnetic field directly influences both the clearance narrow channel (6) on both sides of the coil (7) and the magnetorheological fluid inside the orifice (3). With this effect, the magnetic particles inside the hydraulic fluid having magnetorheological properties create a resistance against the flow by aligning in a direction perpendicular to the flow direction. With this resistance, the bearing stiffness is changed dynamically and rapidly. In this way, sudden changes can be responded to quickly with only an electric current, without requiring any other mechanical effect. At the same time, the system can additionally function as a brake by creating an effect that will completely restrict or significantly slow down the motion of the system at the amount of high electric current excitation to be applied. As fields of the subject invention within the scope of industry; hydraulic rotary actuators used in devices such as military armored vehicles, cargo ship covers, mobile cranes, mining machinery, garbage collector trucks, construction machinery, and special machinery are actuators enabling the piston, moved linearly by means of hydraulic fluid, to rotate the shaft to which it is connected via an internal and external gear system between certain angles. It is required to perform a bearing between the shaft to which it is connected and the body. This bearing must perform a bearing with different stiffness according to the load to which the actuator will be connected, and the provision of the precision of the rotary system is also required. At the same time, the rotating actuator is also required to be locked with the braking system. The hydrostatic bearing to be used in this system both offers a stable stiffness and will assist the braking system. Hydrostatic bearings are used in machines requiring precision machining such as CNC benches, milling machines, and lathes, because they offer high precision by providing less friction compared to other bearings. In these machines, there is a bearing requirement at different loads according to the machining method and the nature of the processed part, and this can be performed with the bearing in this patent in a manner enabling control easily. The bearing in this patent proposal, which is easy to control and will also assist in performing braking, can be used for precise motion and stability in coordinate measuring machines (CMM), laser scanners, and optical measuring devices, which are High Precision Measurement Devices. In turbines, compressors, and pump systems having high-speed rotor systems, hydrostatic bearings are preferred to operate with minimum vibration at these high speeds. A quite precise control is required to be able to operate with minimum vibration at these speeds; this can be provided with this proposed patent. Similar situations are also the case in satellite mounting systems, telescopes, and other space vehicles requiring precise control. In components of industrial robots requiring linear motion and when precise positioning including stopping is required, the use of a hydrostatic bearing like in this proposed patent carries importance.

Claims

CLAIMS1. A hydrostatic bearing with magnetic control and braking effect, characterized in that it comprises: a bearing body (1), an inlet port (2) opened from the upper surface of the body (1) towards the inside of the body (1) and enabling the fluid to enter by circulating around the entire body (1), a pressure-reducing orifice (3) enabling the fluid inside the inlet port (2) to enter the bearing surface, a recess (4) located at the outlet of the orifice (3) and in the inner part of the body (1), a shaft (5) located inside the body (1), a narrow channel (6) opened between the body (1) and the shaft (5), an electromagnetic coil (7) placed on the shaft (5).

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