CN108317159B - A lubricated bearing suitable for multi-degree-of-freedom spherical motion device - Google Patents

Abstract

The invention provides a lubricating bearing suitable for a multi-degree-of-freedom spherical motion device, which includes a complete spherical inner shell and a non-complete spherical outer shell, the inner shell is installed in the outer shell, and the outer surface of the inner shell and the inner surface of the outer shell are The center of the ball coincides with the spherical surface. The shell is connected and fixed by two bolts. The inner surface of the shell is provided with a spiral arc groove with a helix angle ranging from 10° to 15°. Inside the groove is a cage for installing balls. The outer surface of the shell There is an oil inlet hole, and the injected lubricating oil enters the spiral raceway, so that a layer of lubricating oil is filled between the inner and outer shells, and a layer of sealing ring is arranged between the inner and outer shells to prevent the lubricating oil from leaking. The invention has a compact and reasonable structure and is easy to install. The balls in the spiral arc groove can bear large radial loads, axial loads, and combined loads that exist simultaneously in the radial and axial directions, and change sliding friction into rolling friction to achieve It avoids the change of the friction type, reduces the friction coefficient, has good wear resistance, and prolongs the service life.

Description

A lubricated bearing suitable for multi-degree-of-freedom spherical motion device

technical field

The invention relates to the technical field of lubricating bearings, in particular to a lubricating bearing suitable for a multi-degree-of-freedom spherical motion device.

Background technique

With the rapid development of modern industry and manufacturing industry, various devices and driving components that need to realize spherical multi-degree-of-freedom motion, such as multi-degree-of-freedom motion motors, are emerging. The motion characteristics have a more significant impact, and it is necessary to continuously improve the performance of lubricated bearings suitable for multi-degree-of-freedom spherical motion devices. Compared with the existing oil film sliding bearings with only inner and outer spherical shell structures, the inner surface of the shell is provided with two circular cycles. Bearings with a raceway structure, linear motion bearings in which the balls are arranged axially on the raceway, and bearings with inclined grooves have better performance.

The existing oil film sliding bearings of multi-degree-of-freedom spherical motion devices composed of inner and outer spherical shells still have many deficiencies in the supporting effect. The inner and outer shells of the bearing are filled with liquid lubricating oil. , the lubricating film generates hydrodynamic pressure to resist the load on the bearing to form an oil film support, which is mainly based on sliding friction, and the sliding contact area is large. Although it can also bear a large load, the difference between the static and dynamic friction coefficients is small, and the friction force Large, easy to cause serious wear, inflexible movement, poor stability, low positioning accuracy, not suitable for devices such as multi-degree-of-freedom motors to achieve high-speed operation and precise micro-motion; poor fault tolerance, when a part of the bearing device fails, the entire device It cannot run normally, resulting in a waste of resources and significantly reducing work efficiency. Bearings with a two-circle circular raceway structure and an axial linear raceway structure, the rolling friction between the ball and the inner shell is dominant during circumferential and axial movements, but when it moves along multiple degrees of freedom During direction deflection motion, the friction form between the inner and outer shells is still dominated by sliding friction, and the two raceway structures are far from meeting the needs of multi-degree-of-freedom motion. Although bearings with inclined grooves can operate under multi-degree-of-freedom motion conditions, they are not suitable for the special asymmetric spherical structure supporting the multi-degree-of-freedom motion motor stator and rotor with a single output shaft, and use Short life.

Therefore, it is urgent to propose a new lubricating bearing suitable for multi-degree-of-freedom spherical motion devices that can reduce friction loss, high-precision positioning, and flexible control. The design of the bearing groove must be suitable for asymmetric and non-complete spherical structures. In the working condition of rotation or deflection, rolling friction is the main factor among the parts, the friction coefficient should be small, and the operation should be stable.

Contents of the invention

The purpose of the present invention is to provide a lubricating bearing suitable for multi-degree-of-freedom spherical motion devices, to solve the problem that the prior art bearings are dominated by sliding friction, resulting in large friction, serious wear, and short service life, which leads to the multi- The adaptability of the spherical motion of the degree of freedom is poor, which affects the overall operating performance and even fails to operate normally.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

The invention provides a lubricating bearing suitable for a multi-degree-of-freedom spherical motion device, which includes a complete spherical inner shell and a non-complete spherical outer shell, the inner shell is installed in the outer shell, and the outer shell of the inner shell The surface and the inner surface of the shell are spherical surfaces whose centers coincide. When the opening of the shell is closed, it is connected and fixed by two bolt assemblies. The inner surface of the shell is provided with a groove, and the inside of the groove is set There is a cage, and a plurality of evenly distributed balls are placed in the cage; an oil inlet hole is arranged on the outer surface of the outer shell, and liquid lubricating oil is filled into the inner shell and the inner shell through the oil inlet hole. The outer shell is sealed by the sealing ring provided between the inner shell and the outer shell.

Further, the groove is specifically set in a spiral arc shape with a helix angle in the range of 10° to 15°, the cage is set in a spiral arc shape, and the spiral arc-shaped cage and the spiral arc shape match the grooves.

Still further, the material of the cage is specifically a composite non-metallic material, and the composite non-metallic material includes nylon, phenolic tape or polytetrafluoroethylene.

Still further, the non-complete spherical side of the housing is specifically set as a horizontal housing end surface.

Still further, the height of the end surface of the outer shell on the outer shell is 20-30mm lower than the height of the top surface of the inner shell.

Still further, the bolt assembly includes nuts and bolts, and the bolts pass through the connecting holes on the housing and are then tightened and fixed by the nuts.

Still further, the material of the ball is specifically non-magnetic ceramic material.

Still further, the material of the sealing ring is specifically rubber.

Compared with prior art, beneficial technical effect of the present invention:

The invention is suitable for lubricating bearings of multi-degree-of-freedom spherical motion devices. The inner shell and the outer shell are directly assembled together, and the outer shell is connected and fixed by bolts and nuts. The design of the spiral arc-shaped groove on the surface conforms to the special structure of the spherical shell, which provides enough lubrication space for the balls, significantly reduces the possibility of bearing fatigue damage, and at the same time plays a buffer role in the operation of the bearing and facilitates transmission. , discharge frictional heat and cooling; the cage is made of composite non-metallic material, which has good strength and elasticity, high temperature resistance, corrosion resistance, and only a small friction is generated when it moves relative to the surface of the ball, and the balls are evacuated and fixed to prevent the balls The direct contact of the ball reduces the friction and heat generation to a minimum, and guides the ball to rotate in the correct groove, improving the internal load distribution and lubrication performance of the bearing; the design of the ball increases the bearing capacity, and can bear radial load, axial load Load and combined radial and axial loads, the contact between the ball and the surface of the inner shell is a point contact, which reduces the friction during the power transmission process by rolling and improves the transmission efficiency of mechanical power; the liquid lubricating oil passes through the surface of the shell The oil inlet hole enters the spiral arc-shaped groove to lubricate the balls to reduce the friction force when the balls roll, and to reduce the oil temperature by injecting lubricating medium exchange and improve the working environment of the bearing; the sealing ring The design can protect the bearing, prevent foreign dust and other sundries from invading the inside of the bearing, and effectively prevent the leakage of lubricating oil. The invention changes the sliding friction of the multi-degree-of-freedom spherical motion device into rolling friction through structural optimization, reduces the friction torque and factor, and prolongs the service life of the multi-degree-of-freedom spherical motion device.

The structure design of the invention is ingenious and reasonable, the structure is simple and reliable, and the installation and disassembly are convenient and quick. The special spiral arc groove design improves the uniform distribution of the internal load of the bearing, which is most conducive to the uniform distribution of the balls and ensures the uniformity of the load along all directions of the spherical surface to the greatest extent; the helix angle determined after design analysis is in the range of 10° to 15° The spiral arc-shaped groove can minimize the stress, strain and displacement of the bearing structure; the ball changes the sliding friction into rolling friction, realizes the change of friction type, reduces the friction coefficient, and has good wear resistance. It has improved bearing capacity, can bear radial load, axial load and combined radial and axial load, has stable rotation, low vibration and noise, and is more suitable for multi-degree-of-freedom rotation, which can meet the needs of multi-degree-of-freedom spherical motion devices.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the schematic diagram of the lubricated bearing structure applicable to the multi-degree-of-freedom spherical motion device of the present invention;

Fig. 2 is the lubricated bearing structure applicable to the multi-degree-of-freedom spherical motion device according to the present invention along the end face of the housing;

Fig. 3 is a schematic diagram of a vertical section of a lubricating bearing structure of the present invention and a helix angle of a spiral arc groove (taking 10° as an example);

Fig. 4 is a schematic diagram of the structure of the spiral arc groove on the shell of the present invention;

Fig. 5 is a structural schematic diagram of a ball and a cage of the present invention;

Explanation of reference signs: 1, inner shell; 2, outer shell; 3, ball; 4, end face of shell; 5, sealing ring; 6, nut; 7, bolt; 8, groove; 9, cage; 10, oil inlet hole.

Detailed ways

As shown in Figures 1 and 2, a lubricated bearing suitable for a multi-degree-of-freedom spherical motion device includes a complete spherical inner shell 1 and a non-complete spherical outer shell 2, and the inner shell 1 is installed on the outer shell 2 inside, and the outer surface of the inner shell 1 and the inner surface of the outer shell 2 are spherical surfaces with overlapping spheres, which can complete multi-degree-of-freedom movements and have a strong bearing capacity; when the opening of the outer shell 2 is closed, it passes through two The bolt assembly is connected and fixed. The bolt assembly includes a nut 6 and a bolt 7. The two incomplete hemispherical shells of the casing 2 are aligned, and then the bolt 7 passes through the connection hole on the casing 2 and is tightened and fixed by the nut 6. The design of the split shell makes the installation of the inner shell more convenient, without heating, it can be directly installed inside the shell, the installation and disassembly are convenient and fast, and it is convenient for maintenance.

As shown in Fig. 3, Fig. 4 and Fig. 5, a groove 8 is provided on the inner surface of the housing 2, and a cage 9 is arranged inside the groove 8, and a plurality of Evenly distributed balls 3; the outer surface of the outer shell 2 is provided with an oil inlet hole 10, through which liquid lubricating oil is filled between the inner shell 1 and the outer shell 2, which is convenient for bearing For the maintenance and maintenance, the friction between the ball and the inner shell and the outer shell is reduced or eliminated with the help of lubricating oil, and the oil temperature is lowered by injecting the lubricating oil medium to exchange, so as to prevent the burning phenomenon caused by the high temperature of the bearing; through the inner shell 1 and the The sealing ring 5 provided between the shells 2 is used for sealing. The setting of the sealing ring can prevent the leakage of lubricating oil, and at the same time play a good waterproof and dustproof effect, and can also play a certain supporting role.

Specifically, the groove 8 is specifically set in a spiral arc shape with a helix angle of 10°, 15° or any helix angle from 10° to 15°, the cage 9 is set in a spiral arc shape, and the spiral circle The arc-shaped cage 9 matches the spiral arc-shaped groove 8 . The material of the cage 9 is specifically a composite non-metallic material, and the composite non-metallic material includes nylon, phenolic tape or polytetrafluoroethylene. The design of the spiral arc-shaped groove 8 provides a lubricating space for the ball and acts as a buffer for its movement; the cage 9 has good strength and elasticity, high temperature resistance, corrosion resistance, and only a small amount of movement occurs when it moves relative to the ball surface. Small friction, evacuation fixes each ball, prevents direct contact of each ball, minimizes friction and heat generation, and guides the ball to rotate in the correct groove 8.

The non-complete spherical side of the housing 2 is specifically set as a horizontal housing end surface 4 . The height of the outer shell end surface 4 on the outer shell 2 is 20-30 mm lower than the height of the top surface of the inner shell 1 .

The material of the ball 3 is specifically non-magnetic ceramic material. The material of the sealing ring 5 is specifically rubber.

Working process of the present invention is as follows:

First, the lubricating bearing of the present invention is assembled, and then installed on a multi-degree-of-freedom spherical motion device such as a multi-degree-of-freedom motor. The rotor is installed in the inner shell of the bearing, and the rotor is driven by external forces such as electromagnetic force to drive the lubricating bearing to complete the multi-degree-of-freedom Movement, changing the direction and magnitude of the external force can realize the rotor and bearing running in different directions. When the bearing is working, the outer shell 2 remains stationary, the inner shell 1 rotates, and the liquid lubricating oil and the ball 3 rotate together with the inner shell 1. The two separate the friction surfaces of the inner and outer spherical shells and bear the load. The ball 3 and the The surface contact of the inner shell 1 and the outer shell 2 is point contact, and they operate in a rolling manner. The cage 9 is fixedly installed on the groove 8, which evenly separates the balls 3 from each other, and guides the balls to move on the correct raceway.

The invention can realize multi-degree-of-freedom movement, the ball changes sliding friction into rolling friction, realizes the change of friction type, reduces friction coefficient, has good wear resistance, improves bearing capacity, and can bear radial load, axial load Load and combined radial and axial loads prolong the service life of the equipment.

The above-mentioned embodiments are only to describe the preferred mode of the present invention, not to limit the scope of the present invention. Without departing from the design spirit of the present invention, those skilled in the art may make various Variations and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (7)

1. a kind of lubrication bearing suitable for multiple degrees of freedom spheric motion device, it is characterised in that: including complete sphere The shell (2) of inner casing (1) and an incomplete spherical surface, the inner casing (1) is mounted in the shell (2), and the inner casing (1) Outer surface and the shell (2) inner surface be the centre of sphere be overlapped spherical surface, the shell (2) opening closure when pass through two Bolt assembly is connected and fixed, and the inner surface of the shell (2) is equipped with groove (8), and the inside of the groove (8), which is equipped with, to keep Frame (9), the retainer (9) is interior to be placed with multiple uniformly distributed balls (3)；The outer surface of the shell (2) is equipped with fuel feed hole (10), liquid matter lubricating oil is filled between the inner casing (1) and the shell (2) by the fuel feed hole (10), and passes through institute The sealing ring (5) being equipped between inner casing (1) and the shell (2) is stated to be sealed；The groove (8) be specifically configured to 10 °~ The spiral circle arc of 15 ° of range helical angles, the retainer (9) are set as spiral circle arc, and the guarantor of spiral circle arc It holds frame (9) and the groove (8) of spiral circle arc matches.

2. the lubrication bearing according to claim 1 suitable for multiple degrees of freedom spheric motion device, it is characterised in that: described The material of retainer (9) specifically uses composite non-metallic material, and the composite non-metallic material includes nylon, phenolic aldehyde adhesive plaster or poly- Tetrafluoroethene.

3. the lubrication bearing according to claim 1 suitable for multiple degrees of freedom spheric motion device, it is characterised in that: described The incomplete spherical surface side of shell (2) is specifically configured to horizontal shell end face (4).

4. the lubrication bearing according to claim 3 suitable for multiple degrees of freedom spheric motion device, it is characterised in that: described The shell end face (4) on shell (2) is highly lower than the 20~30mm of apical side height of the inner casing (1).

5. the lubrication bearing according to claim 1 suitable for multiple degrees of freedom spheric motion device, it is characterised in that: described Bolt assembly includes nut (6) and bolt (7), and the bolt (7) passes through the spiral shell after the connecting hole on the shell (2) Female (6) are tightened.

6. the lubrication bearing according to claim 1 suitable for multiple degrees of freedom spheric motion device, it is characterised in that: described The material of ball (3) specifically uses non-magnetic ceramic material.

7. the lubrication bearing according to claim 1 suitable for multiple degrees of freedom spheric motion device, it is characterised in that: described The material of sealing ring (5) specifically uses rubber.