JP2007162926A - Fluid friction transmitting force limiting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To moderate impact shock in connecting driving force and to increase a speed of viscous rotation. <P>SOLUTION: The speed of viscous rotation is increased by stacking a raceway surface composed of a plurality of conical surfaces on a torque transmitting passage and a skewed roller to rationally distribute driving force. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a torque transmission amount control device.

The clutch that intermittently or adjusts the driving force of the mechanical device was originally a multi-plate clutch that piles up the discs and presses the discs with electromagnetic force or pneumatic oil pressure and transmits and adjusts the power by friction, A high-viscosity fluid made of silicon oil is sealed in a container, and a thin disk is stacked in the container, and a viscous joint that transmits power by viscous resistance (commonly called viscous coupling). Also called ERF using electrorheological fluid. There are viscous fluid clutches, electromagnetic powder clutches that transmit magnetic power by magnetic friction between particles by electromagnetic force. In recent years, the EHL oil film has a traction function that transmits power by the shear resistance of the solidified film, such as the glass transition, under the high pressure of the Hertzian contact of the rolling elements, and the viscous slip due to the viscoelastic plastic deformation of the oil film. There is a pressure viscous fluid clutch to transmit. The principle of this is shown in Japanese Patent No. 2903325. When a torque is applied by interposing a scoop and a roller inclined between the inner ring raceway surface and the outer ring raceway surface, which are conical surfaces, the rollers are wedge-shaped in the shape of the inner and outer rings. Fluid friction transmission force that variably transmits strong torque from viscous sliding state to direct coupling by plastic deformation and shear resistance of elastohydrodynamic lubricating oil film of strong oil film generated by rolling while biting between raceways and confined in rolling surface at that time There is a limiting device.

As a supplementary explanation of the elastohydrodynamic lubrication theory (EHL) described above, Dowson, G.M. Higginson & A. V. Whitaker: J. et al. Mech. Eng,. 4, 2 (1962) 121. In recent years, it has been well-known and advanced academically in the development of vehicle transmissions. However, the technical idea of taking out rheology (viscous fluid characteristics) from an EHL oil film and causing it to function as a mechanical element, like the aforementioned electro-rheological fluid (ERF), has not yet been scientifically explored, and remains at the discovery stage of the phenomenon. . The purpose of implementing the rheological function of the EHL oil film of the present invention is to apply it to a differential limiting device that detects the rotational difference between the front and rear wheels of a four-wheel drive vehicle and automatically distributes the power smoothly to the wheels having the appropriate driving force. In addition, the versatility of the driving force transmission device of various other mechanical devices is wide, and the following patents have been filed for improved techniques using the principle.
In the technique of the improvement implementation with respect to the elastic fluid friction limiting device of the said patent 2903325 JP-A-4-362324 Engages both ends of the roller of FIG. 1 with a planetary gear and changes the inclination angle (skew) of the roller according to its revolution phase to make the viscosity sliding speed variable. JP-A-6-109038 engages one end of the roller of FIG. 2 with the phase of the planetary gear to change the skew angle, thereby making the viscosity sliding speed variable. 2 is engaged with a friction member, and the skew angle is made variable by a delayed advance force due to the friction. The roller shown in FIG. 2 of JP-A-7-71485 is put in a case, and a phase is given at both ends of the case to change the skew angle of the roller to make the speed variable. Japanese Patent Application Laid-Open No. 2003-184910 claim 1 Instead of the roller of FIG. 1, a long needle is used and one end of the needle protrudes from the conical raceway surface and engages with a ring groove to swing the ring. Use to change the roller skew angle. The axial displacement of the bearing ring shown in FIG. 5 of JP-A-2003-184910 is countered by the Hertz elasticity of the ball, and the oil film thickness is increased to increase the sliding speed. An alternative to the electromagnetic clutch shown in FIG. 2 of Japanese Patent Application Laid-Open No. 2004-183883 makes an electromagnetic coil and electric power unnecessary. Etc.

  Many of the above-described differential limiting devices are arranged on the drive shaft of a 4WD vehicle, and since the high-speed rotation and high torque are used, the mechanism is required to be robust, lightweight, and simple. The function is a device that detects the slip instantaneously when the driving wheel slips on the road surface with low friction and distributes the power to the wheels having the driving force in a concentrated manner. In this case, the vehicle speed during forward (forward rotation) and reverse (reverse rotation) (Rotating speed of the shaft) is extremely different, so differential rotation detection and torque transmission are sensitive to differences of about 100 to 500 revolutions per minute during forward movement (forward rotation), and extremely large during reverse movement (reverse rotation) Sensitivity at 100 rotations or less is desirable due to low speed, but the on-demand type viscous joint (viscus coupling) currently in practical use has a disadvantage that it is sensitive only at the same speed during forward and backward movements.

Patent No. 2903325 used in the present invention has the same problem as described above, and furthermore, since the technology depends on the creep speed of plastic deformation of the elastohydrodynamic lubricating oil film, the surface pressure also increases at high torque loads. Along with this, the solidification of the oil film progresses, and the creep speed becomes slow without being proportional to the torque, and in order to obtain a desired speed, there is a problem that it is necessary to use a speed-up gear and the like to make it complicated. Therefore, in order to solve the above-mentioned problems over the past 15 years with respect to the patented technology, when the skew angle is zero, the configuration is very similar to a rolling bearing and rotates smoothly, so torque transmission is zero but the skew angle is increased. Then, with the technical idea that viscous resistance gradually appears and eventually changes to a dog clutch that transmits 100%, the (skew) inclination angle of the roller can be varied in the range of 0 to 10 °, and the speed can be directly connected to 0. The invention to make variable has been invented as listed in the background art by the same inventor as the aforementioned principle patent No. 2903325. However, since the viscous sliding speed depends only on the creep phenomenon of plastic deformation of the solidified oil film, only the skew angle changes only about 10 to 20%, and there is a problem that the structure becomes complicated.

In addition, when a high-speed rocking torque of 10 Hz or more was applied, the input / output shafts violently displaced in the axial direction, and a spline or the like was required to absorb this. However, this part repeated repeated sliding contact, resulting in secondary problems such as wear due to fretting and increased play. Also, when trying to control the viscous sliding speed by changing the oil film thickness, the oil film thickness is less than 0.3 microns, so the corresponding position in micron units must be controlled accordingly and the linear expansion and contraction caused by temperature changes Because the dimensions fluctuated, there was a very difficult problem.

  A patent in which a torque is transmitted from an inner ring to an outer ring with a viscous slip when a roller is engaged between the inner ring raceway and outer ring raceway formed by a conical surface and a roller is engaged in a wedge shape. In the fluid friction transmission force limiting device of No. 2903325, four or more raceway surfaces that generate surface pressure when torque is loaded are used.

The present invention has the following inventive steps and effects over the background art.
In other words, the configuration is robust and simple, can transmit high torque with viscous slip, and the control of the viscous slip speed is easy, and if it is used in a gear transmission, it absorbs the rotation difference of the gear with the viscosity of the oil film. Therefore, the synchronizer ring of the thin friction cone clutch for synchronizing the gear, which has been conventionally used, becomes unnecessary. In addition, the thrust component due to traction is generated in the roller by the input torque and automatically attracts to the other side, so when replaced with the conventional electromagnetic clutch, the energy of pressing force such as electromagnetic force and air pressure becomes unnecessary, so the electromagnetic coil Energy saving and energy saving, greatly reducing weight and simplification. In addition, since the present invention has a high absorber function that absorbs all violent vibration torque, the transmission system is prevented from vibration against input that involves torque fluctuation, and there is no wear deterioration due to vibration. Furthermore, in the differential limiting device for an on-demand type 4WD vehicle shown in the application example of the present invention, the conventional viscous coupling can distribute the driving force only at the same vehicle speed at the time of forward and backward movements, whereas in the present invention. The distribution can be changed between forward and backward, which not only increases vehicle safety, but viscous coupling also increases the speed of viscous rotation in proportion to the input torque. There is also a problem that the driving force is inadvertently flown and lacks steering stability because it is also sensitive to the differential rotation that occurs naturally.

On the other hand, the present invention relies on creep due to plastic deformation of the oil film, so that almost no torque is transmitted to the set vehicle speed, and torque does not flow except when a wheel slip occurs, and steering stability is not hindered. In addition, the present invention transmits torque with only one or two meshing teeth like the gear of the conventional torque transmission means, whereas a large number of rollers are arranged on the circumference so that all the rollers are torqued simultaneously. Therefore, it has a large torque capacity, and since the rolling bearing and the parts are common in manufacturing, it is low in cost and high in mass productivity. As described above, the present invention, in which shear resistance and rheological components are extracted from the EHL oil film and function as a force transmission medium, is a novel machine element and has great inventive step and effect.

FIG. 1 of the embodiment
FIG. 1 is a schematic view of a cross section showing a first embodiment of claim 1, wherein conical raceway surfaces 13 and 14 for applying torque are combined in the reverse direction as shown in the figure, and the skew direction is reversed. By laminating the rollers as shown in FIGS. 2 and 5, the input / output shaft axial displacement of the intermediate race 3 is substituted for the axial relative displacement between the input shaft and the output shaft, which occurred in Japanese Patent No. 2903325. The spline required on the shaft is no longer necessary, and the frictional resistance and wear of the spline portion are eliminated, and the surface causing viscous sliding and elastic displacement is doubled, so that torque fluctuation is absorbed and the viscous sliding speed is doubled.

FIG. 2 of the embodiment
FIG. 2 of the embodiment is a schematic view of the outer appearance of FIG. 1, wherein reference numeral 1 is a driving side, inner raceway, 2 is a follower side raceway, and 3 intermediate raceways have inner and outer diameter surfaces opposite to each other. Consists of a conical surface. The generatrix of the conical surface of the raceway surface may be a straight line when using a needle roller that has a thin and flexible roller, and conversely, a thick and highly rigid roller is formed with a hyperbola to obtain line contact. An outer (outer) roller 4 and an inner (inner) roller 5 are disposed between the conical raceway surface of the intermediate raceway ring 3 and the conical raceway surfaces 9 and 13 of the inner raceway ring 2 and the outer raceway ring 2. 2 and 5 at the intervals of about 2 mm on the circumference of the conical raceway surface of the intermediate raceway ring 3 and the inner raceway ring 9 accommodated in the pocket holes of the inner cage 12 and the reverse skew angle as shown in FIGS. Is given and held. The width dimension of the inner cage 11 and the outer cage 12 is restricted in position by waiting for play in the axial direction so as not to disturb the axial displacement of the roller (not shown).

The material used for each part is explained. The conical race rings 1 and 2 and the intermediate race ring 3 are hardened to a hardness of HRC 60 or higher by heat treatment, and the raceway surface is subjected to a grinding finish suitable for oil film construction. It is. Similarly, the roller hardens the bearing steel to HRC63 or more by heat treatment and finishes the roundness to 0.001 mm or less by grinding. The cages 11 and 12 for imparting a skew angle to the roller press-mold a polished steel plate, and punch a pocket hole into which the roller enters by punching. Thereafter, the surface is soft-nitrided and cured. These materials and parts can be used for mass-produced JIS rolling bearings, which is advantageous in terms of accuracy and cost. The cages 11 and 12 may be molded products in which 66 nylon containing glass fiber is injected with a mold. The intermediate race ring 3 is pressed against the conical surface of the inner and outer races from the side by the elasticity of the disc spring 6. When the torque is applied, the inner and outer rollers 4 and 9 must contact the raceway surfaces 9 and 13 at the same time to generate traction. Therefore, the inner ring raceway surface 9, the outer ring raceway surface 13 and the inner and outer conical surfaces 4 of the intermediate raceway surface are required. Match each part with a taper gauge. In addition, the dimensional difference between the diameters of the rollers is set to 0.002 mm or less. Furthermore, in order to reduce the assembly error of the inner and outer conical raceway surfaces, the internal clearance of the ball bearing is made negative to reduce the amount of axial movement, so that the clutch function operates more accurately.

The intermediate race 3 is divided into a circular ring with a conical surface on the inside and a male spline on the outer diameter, and a ring with a conical surface on the outside and a female spline with the inner diameter, and divided into two layers as shown by the double broken line 14 in FIG. Then (the double broken line is omitted in the schematic external view 2) Since the two-layer members are individually slid in the axial direction on the spline fitting surface, even if there is a slight error in the diameter of the conical surface, It is only necessary to press 3 to the conical surface of the track with the spring 6, and the traction is generated at the same time by contacting the inner track 9 and the outer track 13 by the thrust component of the inner and outer rollers 4 and 5, respectively. Matching with the tepper gauge is not necessary. This also applies to FIGS. 3, 4 and 5 of the embodiment (not shown).

When an input torque is applied between the inner raceway shaft 1 and the outer raceway 2 in such a configuration, the rollers 4 and 5 have a skew angle of 6 ° given by the pocket hole of the cage due to the relative displacement between the outer raceway and the inner raceway. Rolls along a skew angle appropriately selected in the range of -12 ° and -6 ° to 12 °, and thrust is generated in the intermediate raceway 3 by the axial component of the traction of the roller, so that the inner raceway 1 and the outer raceway Screwed while rotating between the conical surfaces of the ring 2. When screwed, the contact surface pressure of the roller rises, and the oil film confined under Hertz contact based on the theory of elastohydrodynamic lubrication solidifies and transitions, generating friction torque and simultaneously starting viscous sliding rotation. When reverse torque is applied to the inner and outer races, the roller rolls in the opposite direction along the skew angle, and the intermediate race is moved away from the disc spring by the thrust component of the reverse traction. become. The forward torque control has been described above. However, in the case of controlling the reverse torque, the devices may be opposed to form a pair. In addition, since the rollers 4 and 5 can be accommodated as many as needle bearings and the raceway surface is in rolling contact like the rolling bearing, there is no wear, and the intermediate raceway ring 3 is always pushed into the conical surface by the disc spring 6. Because there is no backlash because it follows even if it wears out.

FIG. 3 of the embodiment
Referring to FIG. 3 of the embodiment, FIG. 3 is an embodiment of a clutch for turning power transmission on and off, and it functions as a viscous clutch or a simple intermittent clutch depending on the lubricating oil used. The elastic displacement amount in the axial direction of the intermediate raceway ring 3 in FIG. 3 is such that the Hertz elastic displacement members of the rollers are laminated as described above, as shown in FIGS. Since the capacity increases, the operation becomes easy. When the flange 16 at the tip of the extension member 15 connected to the intermediate raceway is displaced by the arm lever 17 in the direction of the arrows 19 and 20 in the figure, the intermediate raceway moves to the side away from the roller and is free to rotate. When it is pushed in, fluid lubrication starts with the sealed lubricating oil, and the roller once floats on the oil film and slightly repels the urging force, but when pressed lightly, it starts rolling in the skew direction by the traction of the roller and sucks into the other raceway surface To start elastohydrodynamic lubrication. Since the rotation difference between the input and output shafts is absorbed by the oil film in the process from the free rotation to the direct coupling, a so-called full-sync clutch clutch that reaches the direct coupling without a shock is obtained.

Also, when the lever 17 is driven by a self-holding type ultrasonic motor or the like, the torque is connected by the attractive force of the clutch itself only by making the clutch approach. The energy at the moment of pulling out is sufficient, and there is no waste that it keeps consuming electric power to maintain the crimping during torque transmission like a conventional electromagnetic clutch. The oil film is formed in all the processes from the idling state to the direct connection, and there is no metal contact, so there is no wear even if it is repeatedly turned on and off, and the load torque is shared by all the rollers at the same time, so the torque capacity is large and the durability strength Excellent.

FIG. 4 of the embodiment
FIG. 4 of the embodiment will be described. FIG. 4 shows a pulley with a built-in clutch of an alternator that rotates at a high speed and is driven by an engine accessory driving belt of a vehicle. The input shaft of the alternator is press-fitted and fixed to the inner diameter 55. In a diesel engine or the like, the torque fluctuation is large, and the belt over the pulley of the crankshaft causes severe unequal speed. However, since the alternator tries to rotate at a constant speed with an inertial force, there is an inconvenience that the belt undergoes excessive tension fluctuations and deteriorates.

Conventionally, as a countermeasure against this problem, a pulley type one-way clutch with a small number of rollers is built-in and the surface is repeatedly subjected to surface pressure in a very narrow range with a wedge angle of about 4.5 ° and a roller transfer range of 2 mm or less. It was. However, with the recent reduction in the size and speed of alternators, there has been a problem that a repeated torque of about 20 Nm acts on the pulley and the durability of the built-in clutch is insufficient. FIG. 4 of the alternative embodiment has double the displacement amount due to the Hertz elastic displacement of the rollers 42 and 43 and the expansion and contraction elasticity of the two rings of the inner and outer rings 44 and 45 as compared to FIG. 1 of the embodiment. Torque fluctuations can be absorbed by such a large torsional elastic displacement. The number of rollers 42 and 43 can be accommodated as much as a normal needle bearing, and the roller rolls on the raceway surface, so there is no wear, and the intermediate raceways 44 and 45 are always conical on the disc spring 24. There is no backlash because it is pushed in. The rollers and bearing rings, grease, hermetic seals, and the like used for these are made of the same material as that of the rolling bearing, are in rolling contact, and are very similar to the usage conditions of the rolling bearing, and are excellent in reliability and durability.

Example FIG.
Embodiment FIG. 5 shows an embodiment in which the technical idea of claim 1 is used as a differential limiting device for a vehicle. Reference numeral 25 denotes an input shaft, and 33 denotes an output shaft. In FIG. 5, the track surface has six conical surfaces in total including the inside and outside. Of these, 39 and 56 of the raceway surfaces are fitted with rollers 55 and 58 which are meshed with each other by the cages 26 and 60 during normal rotation at −α °. Further, on the raceway surface 57, a roller 27 having an α ° opposite to the skew direction engaged with the cage 23 during reverse rotation is interposed. Here, the skew angle is determined in the range of 6 ° to 12 ° according to the creep rate of the lubricant and the type of additive. The materials and parts used are the same as JIS rolling bearing members and parts.

Here, the operation when torque is applied will be described. When the torque is applied to the input shaft 25 in the rotational direction of the arrow 51 in FIG. 6 corresponding to forward movement in the vehicle, the roller 27 is skewed on the track surface 57 provided on the shaft. The torque is not transmitted to the outer ring 60 in the overrunning state by rolling toward the exit side in the direction of the angle α °. However, the adjacent raceways 39 and 56 on the same axis roll to the side where the rollers 58 and 55 are engaged in accordance with the skew -α °, and torque is transmitted to the outer ring 28 by traction, via the inner ring 29 of the extension part of the same outer ring. Then, it is transmitted to the outer ring 59 by the action of the roller 56 and output to the output shaft 33 engaged with the spline portion 32 of the extension portion ahead of it. The torque transmission path is shown by an arrow 53 in FIG.

Further, when torque is applied in the direction of the rotation direction 52 in FIG. 7 corresponding to the reverse movement in the vehicle, the roller 27 rolls into the biting side and the rollers 58 and 30 become free, so the flow of torque transmission is as shown in FIG. In the direction of the arrow. Therefore, in forward rotation, surface pressure is generated and the roller transfers four surfaces of the inner and outer raceways, so the viscosity speed is doubled. However, in reverse rotation during reverse, the roller 27 is viscous between the two surfaces of the inner and outer rings. Just rolling, the speed is half of the forward.

The apparatus is filled with a lubricating oil that promotes plastic deformation of an elastohydrodynamic lubricating film to which a solid lubricant, such as molybdenum disulfide or tungsten disulfide, that causes layered slippage is added to the traction oil. When it is used continuously under a high torque load, it generates heat, but the oil film becomes thin or breaks and the friction coefficient μ rises to 0.1 or more, and the roller stops viscous sliding and becomes pure rolling contact and bites between the tracks. Lock it. At this point, a transition is made to a normal sprag type one-clutch and the torque is transmitted 100%, and the vehicle behaves as a direct-coupled four-wheel drive vehicle. In the direct connection state, there is no slip heating element, so the function of the viscous joint is restored even if it is air-cooled.The severe operating conditions often occur when the snow or sand path is continuously transmitted, and the heat and cooling are repeated. It is. However, since the entire process is an oil film action and there is no metal contact, there is no damage due to seizure or idling, and the function as a 4WD vehicle is provided as a fail-safe system without losing its lifetime.

  Embodiment FIG. 1 shows that a radial load acts on the pulley 8 by the tension of the belt 56. In this embodiment, the radial load is supported by a ball bearing 7 at one end, and the other is supported by two rollers 4 and 9 by the roller being pressed against the conical surface by a disc spring 6 in a wedge shape.

FIG. 3 of the embodiment is an embodiment in which a torque ON / OFF clutch or a viscous slip clutch is used as a unit as a door lifting device for opening / closing a door or a heavy lifting device such as a fire shutter.

FIG. 4 of the embodiment is an embodiment of a vibration absorbing pulley driven by an alternator of an automobile. The width of the intermediate track ring 44 is widened and the rolling surface of the roller of the intermediate track ring is divided into 44 locations and 45 locations. An embodiment in which the thickness of each pressure receiving portion is reduced, and the amount of expansion and contraction is generated at two locations to increase elastic displacement and absorb large torque fluctuations.

FIG. 5 of the embodiment is an embodiment in which the viscosity speed is set to a ratio of 1 for the forward speed to 2 for the forward speed and is adapted to the use frequency.

  It is used for a wide range of mechanical elements such as differential limiting devices for vehicle drive systems, shock transmission torque transmission devices (torque absorbers), shockless full-sync clutch devices, viscous fluid joints, and heavy load descent devices.

Cross-sectional schematic view of an embodiment of the present invention Is a schematic external view of an embodiment of the invention FIG. 2 is a schematic cross-sectional view of an embodiment of an application of the present invention to an intermittent clutch. The cross-sectional schematic view of embodiment of the clutch built-in pulley of this invention. These are the cross-sectional schematic views of embodiment of the differential limiting apparatus of this invention. Is a functional explanatory diagram of an application embodiment of the present invention to the differential limiting device Is a functional explanatory diagram of an application embodiment of the present invention to the differential limiting device Prior art (improvement technique of Japanese Patent No. 2903325) Japanese Patent Laid-Open No. 4-362324

Explanation of symbols

1. ・ Inner race ring 2. ・ Outer race ring 3. ・ Intermediate race ring 4. ・ Outer roller 5. ・ Inner roller 7. ・ Ball bearing 8. ・ Pulley 9. ・ Inner race surface 10. ・ Retaining ring 11.・ Outside cage 12 ・ ・ Inside cage 15 ・ ・ Bracket 16 ・ ・ Operating flange 17 ・ ・ Operating lever 25 ・ ・ Input shaft 26 and 60 ・ ・ Cage 27 ・ ・ Reverse meshing rollers 28 and 29 ・ ・ Intermediate raceway ring 55, 58 .. Forward meshing roller 38, 40 .. Roller skew angle 31 .. Output outer ring 32 .. Spline 33 .. Output shaft 35, 36 .. Disc spring 57.

Claims (1)

  When a torque is applied by inserting a skewed roller between the inner ring raceway and the outer ring raceway formed of a conical surface, the torque is transmitted from the inner ring to the outer ring with the action of an oil film while the rollers engage with each other in a wedge shape. In the fluid friction transmission force limiting device of Japanese Patent No. 2903325, there are four or more tracks that generate surface pressure when a torque is applied.

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