JP2014149075A - Roller clutch device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roller clutch capable of transmitting a huge torque thanks to shear resistance and plastic deformation resistance caused by a hydraulic pressure enclosed at an ultra high pressure on a raceway surface.SOLUTION: Only mounting rollers 5 skewed by a cage 18 between a shaft having a simple conical surface and an outer ring raceway allows transmission of a huge torque. All the rollers 5 used contribute to torque transmission, thus providing a huge torque capacity. Thanks to self-hold type clutch, it does not require any pushing energy, such as electromagnet, air pressure, and hydraulic pressure, and is thus energy saving.

Description

  Mechanical power interrupting device

  For the transmission control of the driving force of the mechanical device, there are a viscous joint, a fluid joint, a friction plate clutch, a gear and pawl ratchet, a coil spring wrapping friction clutch, a sprag type one-way clutch of the 1932 invention, and a cylindrical roller and many There are one-way clutches with a combination of square cam rings, and recently two-way clutches using it. In contrast to these classical principles, there is a fluid frictional transmission force limiting device, Patent No. 2903325, which utilizes the phenomenon that lubricating oil is trapped and solidified at a high pressure of 3 MPa or more on the rolling contact surface. This is because a scoop and a roller, which are inclined in three dimensions with respect to the rotation axis, are interposed between the inner ring raceway surface and the outer ring raceway surface, which are conical surfaces. The roller rolls between the conical orbits of the inner and outer rings with an axial component, and a high-pressure confined oil film is formed under the contact, and the roller that floats on this transmits torque with the shear resistance of the solidified oil film. is there.

  The above-mentioned oil film is the elastohydrodynamic lubrication theory (EHL) under rolling contact. Dowson,. Higginson. V. Whitaker: J.M. Mech. Eng,. 4, 2 (1962) 121. It is proved that the lubricating oil is confined and elastically solidified at a high pressure, and since then it has been put into practical use in rolling bearings, continuously variable transmissions CVT, etc., and is now a well-known oil film.

Patent No. 2903325 JP 05-149352 A JP2011-144918 Patent 4470588

  The problems of the sprag type and roller type one-way clutch will be described. In the embodiment of the so-called mechanical clutch, there is an autorotation in which the rotor is automatically separated when the engine of the helicopter is stopped. Countermeasures are repeated each time a past defect occurs. In recent examples, the hardness of the sprag is increased to near Hv2000 by the Vickers hardness and the material of the cage is strengthened. However, from a recent tribological point of view, an oil film is trapped at the sprag contact at an ultra-high pressure, and is solidified and fixed in a frozen state. Alternatively, when the load of slight vibration is repeated, the oil component is squeezed out from the contact point and comes into contact with each other, and in this case, it is fixed by the bonding force between the metal molecules. When such sticking occurs, the sprags spring up due to the reaction of the peeling resistance, and the ribbon spring that is holding down is deformed and the cage is damaged (pop-out). Also, even when a fluctuating torque is applied, the sprags elastically resonate. As a result, only a part of the sprags are accidentally engaged, and the sprags are overloaded, buckling and rolling over to the opposite side.

In addition, the sprags are lifted from the orbit due to centrifugal force when rotating at a high speed, and in order to suppress sprag resonance, the sprags are always pressed against the orbital surface with a ribbon spring. As a result, the contacts are rubbed and worn out early. Further, in the roller cam type clutch, the cam surface of the contact is permanently engaged at the same position, so that it becomes indented and wears and cannot be engaged.
In the roller type, the number of rollers to be accommodated is limited, and when a large torque is applied, the raceway ring is deformed into a polygon and stress is concentrated on the thin wall portion of the corner of the cam groove that accommodates the rollers, and is easily broken. The allowable rotational speed during idling is usually limited to 2000 rpm or less. A shock absorbing damper is indispensable for torque vibration and shock input, and a torque limiter is indispensable for excessive input.

With respect to many problems as described above, the problems of Japanese Patent No. 2903325 of Prior Art Document 1 described in the background art and Japanese Patent Application Laid-Open No. 2011-144918 of the improvement will be described.
The feature of the present invention is that if the raceway is separated slightly (1 mm) in the axial direction, the torque is cut off and the forward and reverse free rotation is performed. When lightly touching, the distance between the inner and outer rings of the track becomes narrower (sucked in) due to the axial component of the squeezed roller traction, resulting in a self-holding clutch that self-fastens with torque load. Also, when meshing, the rotational difference between the input and output shafts and the shock are absorbed in the process of the oil film transitioning from viscous fluid to plastic body and elastic body by pressure, and further the Hertz elasticity of the contacts and the expansion and contraction of the inner and outer rings. It becomes an extremely soft cushion type clutch by elastic deformation. Using ester-based lubricants based on this principle, a one-way clutch with no slippage is obtained. If an extreme pressure additive (molybdenum disulfide, fluorine resin, etc.) is used for high-viscosity oil, the speed is constant regardless of the magnitude of torque. Viscous joint with constant velocity that rotates at a high speed.

  When rotating in the opposite direction, it changes from suction to discharge, floats on the oil film, and idles, reducing frictional resistance and saving energy. Further, since the roller is not affected by the centrifugal force, the meshing is always secured with one disc spring. Furthermore, this method has a very large torque capacity. For example, when the size is an outer diameter of φ100 mm, the width is 52 mm, the rollers are φ8 × 32 mm, 18 rollers are used, and the roller surface pressure is 3.0 GPa, the load torque is 150 kg− The capacity is m. The relative displacement in the axial direction of the inner and outer rings is about 3 mm.

The problem in carrying out the above will be described.
The prototype of the present invention is old and started in the actual application No. 39-16385, but has not yet been put into practical use after 49 years of trials by many contractors. The main reason is described. First, the operation of the clutch generates a tangential force, that is, traction, when the skewed roller rolls under pressure in the revolution direction. A part of the traction is converted into an axial component depending on the skew angle, and the conical surface of the inner and outer rings is relatively displaced (hereinafter referred to as suction force) to the side where the interval is narrowed by the axial component. The roller then moves into the conical track and locks. However, when the sliding contact resistance of the essential sliding contact member allowing the relative displacement in the axial direction of the raceway is greater than the suction force, it cannot be completely locked.

The suction force generated by the rolling of the roller depends on the traction coefficient (μ value, μ = 0.04 to 0.08) of the oil agent under the roller contact.
At the beginning of suction, the initial torque is small and the roller surface pressure is low, so that only a small suction force can be obtained, which depends only on the biasing spring force. Incidentally, the one-way clutch is often used as a safety device for preventing reverse rotation of a machine, and if it slips even within the lifetime of its service life, a serious accident occurs. Nevertheless, the clutch has lacked the reliability of the sliding contact portion that ensures the success or failure of the engagement.

To date, a proposal using a spiral spline in the sliding contact portion (4470588 of Patent Document 4) and a spiral ball spline (friction coefficient μ = 0.003) interposing a ball in the spiral groove have been proposed. JP-A-05-149352. The friction coefficient of the sliding contact surfaces of the spline of the above-mentioned device is a smooth surface of steel, the dynamic friction coefficient μ at the time of drying is 0.12, and the static friction that starts is particularly large (maximum static friction coefficient) μ ₀ Is 5 to 6 times the dynamic friction coefficient μ. Especially in the case of using combined power of recent power and internal combustion engine, the sliding contact part causes electric corrosion (corrosion) due to potential difference, electric leakage, freezing in cold district, drying of oil due to long-term stop, biting of foreign matter, There is a risk that the sliding contact portion may be fixed and abnormally increase the starting frictional resistance due to rusting due to condensation and fretting rusting due to minute vibration.

In addition, in the above-described splined Japanese Patent Application Laid-Open No. 05-149352, when a slight vibration torque is applied for a long time, the ball contact is depressed and worn, or when the reciprocating swing distance is 1.5 mm or less, the swing causes a minute swing to remove oil from the contact. It squeezes out to form a dry metal contact, which immediately produces pseudo-indentation (fretting corrosion) and does not hold in terms of surface pressure strength.

Here, a trial calculation example of the magnitude of the sliding friction of the above-mentioned spline will be described. If a torque of 20 kg-m acts on the key, the force acting on the sliding surface of the key reaches 1,000 kgf when the key transmission radius is 20 mm. The starting force of the key, that is, the static friction resistance, is 600 to 700 kgf. To reach.

  The biasing spring force in the thrust direction that supplements the suction force with respect to the static frictional resistance is not far away. Even if the spring pressure is increased, the oil film of the differential slip of the roller that has been skewed during idling is severely sheared, generating heat and braking, resulting in a large energy loss.

In addition, when the above-described spiral spline is used, a thrust component force generated in proportion to the input torque acts on the conical surface of the (axial force) roller clutch, resulting in a disadvantage that the torque capacity is greatly reduced.

Therefore, as a measure to reduce the starting frictional resistance, the process of this mechanism, which is to start the meshing with a low dynamic friction coefficient by avoiding the unstable static friction coefficient region at the start of the spline, is explained with the diagram of FIG. To do. The horizontal axis 36 indicates the clutch suction force, and the vertical axis 35 indicates the input torque. Before the input is applied, the preload biasing spring 22 is pressed in advance as shown in FIG. 3 and 41 in FIG. 11 so that the rotational force is generated in the outer ring 6 in FIG. 40) Then, the spline rotates by the amount of backlash. Before the displacement for the backlash starts, the wedge (cam) slope 12 in FIG. 2 is brought into contact with 12 and 13 in FIG. 5 to generate a thrust (axial force) 44 along the line A in FIG. With this thrust (axial force), the spline sticking due to rust or freezing is first released. After the release, the backlash disappears and returns to the position 41 in FIG. From this point of time, the pressure-receiving surface of the spline apparently comes into contact, torque transmission starts, and the engagement of the clutch starts with the rolling traction in the roller revolution direction. At the same time, a torque is generated by the angle 21 (0 to 5 °) of the spline tooth trace of FIG. 10 by torque, and is displaced along the line 39 in FIG. 11 to complete the fastening. At this time, the displacement along the arrow 38 in FIG. 11 is caused by an oil film (43 in FIG. 6) located around the dimple hole of the plate member 30 interposed in the gap of the spline shown in FIG. ), The oil 43 is squeezed out of the dimple hole 28 by crushing the convex portion of the interposition plate 30 in the elastic range by the shear displacement and the pressure 48, whereby the squeeze fluid film 42 in FIG. As a result, it is displaced with a low frictional resistance of μ = 0.04 (actually 0.01 or less).

When the clutch is unloaded, the backlash 31 is restored to its original clearance by the clip spring 20 shown in FIG. 10 (20 is for explanation and actually due to the elastic reaction force of the spring steel corrugated plate 30). Oil is taken in between the pressure-receiving surfaces. Therefore, since the spring requires fatigue durability against repeated stress, a laminating method as shown in FIG. 12 is preferable in which the amount of deformation per sheet is suppressed. The spring 30 and the clip spring 20 are weakened to such an extent that the fastening action is not hindered.

The relational operation between the spline load and the sliding distance of the clutch will be described. As shown in FIG. 6, as the load 48 due to torque input increases, the amount of displacement also gradually increases with arrows 24 and 25. Finally, in the example where the PCD of the spline is φ50 mm, it is shifted by 3 to 4 mm (depending on the size). Stop. Conversely, in the process of gradually increasing the load from zero while displacing, this displacement of only 3-4 mm is the shear displacement of the viscous deformation of the oil held between the contact surfaces, and the squeeze from the dimple hole The squeeze fluid film can be lifted out of the squeeze fluid film and fall within the operating range. Here, the amount of axial displacement of the clutch is determined by the angle of the conical surface of the clutch and the rigidity due to the wall thickness of the inner ring and the wall of the outer ring, so the rigid wall thickness and the cone angle must be set so that the displacement is within this range. Enlarge. For example, when the load torque is 20 kg-m, the PCD with 6 spline teeth is φ50 mm, and the area of the pressure receiving surface is 75 mm ² , the surface pressure of the pressure receiving surface at the spline is 1.7 kg / mm ² maximum. The oil film strength can withstand sufficiently and can be further reduced by increasing the number of spline teeth.

The operation of the clutch is started by releasing the sticking and sticking of the sliding contact surface at an initial stage where torque is inputted. Therefore, the reference numeral 49 in FIG. 4 is brought into contact with the cam slope 13 provided on the side edge (corner) of the spline teeth 8 of the raceway ring 6 in FIG. 3 and the slope 12 of the side plate 9 in the initial torque input stage. A strong axial force 49 expanded as shown in FIG. In the trial calculation example of the axial force, if the angle of the inclined surface is set to 5 ° with respect to the cross section perpendicular to the rotation axis, the thrust (axial force) is 11.5 times the torque. Since the clutch is lightly biased by a spring in advance, the roller is always in meshing state, so that torque is generated in the initial stage. For example, even if the initial torque of 0.1 kg-m is applied, if the position of the slope portion is 16 mm from the axis, 6.25 kg is generated in the rotation direction at the contact position of the slope. This severing force is amplified 11.5 times as axial force on the 5 ° slope of the cam and reaches 70 kgf. The cam slope is only for generating an axial force, and the slope may be a curved surface, an outer diameter of a roller pin or a ball, or a lever mechanism. (Not shown).

Further, in order to promote the shear displacement arrows 24 and 25 of FIG. 6, the plate member 30 of FIG. 8 including oil is interposed between the pressure receiving surfaces of the splines. In order to maintain the oil content, spring steel is formed into a corrugated shape as shown at 30 in FIG. 6, and the dimple hole 28 in FIG. 13 is provided on the entire surface, and the oil content 43 accumulated in the hole is enlarged by the torque load 48 in FIG. The squeeze fluid film indicated by the arrow 42 in the figure is formed, and as a result, the squeeze fluid film is displaced in a state where it floats by a fixed distance of 3 to 4 mm by mixing the shear displacement and the squeeze oil film. When the intervening corrugated spring 30 is coated with molybdenum disulfide, the viscosity coefficient μ of shear displacement due to layered lubrication becomes μ = 0.001 (experimental value) or less. In order to promote shear displacement, the plate material may be coated with a low-μ material such as fluororesin or DLC treatment (not shown), and further laminated as shown at 30 in FIG.
As a means for ensuring further reliability, an independent unit with a grease-sealed seal in which a high-viscosity lubricant effective for shear displacement is included only in the sliding contact portion is isolated from the surrounding lubricant. This prevents fouling due to the entry of harmful foreign matter, oxygen penetration, and rust caused by condensation. (Not shown)

A description will be given of the presence or absence of harmful effects when the above is implemented.
The axial displacement distance of the race ring due to the wedge action of the initial slope is about 1 mm or less as shown by 49 in FIG. 4 and is far less than the full torque displacement of 3 to 4 mm and does not increase the contact surface pressure of the roller. .

In addition, the clutch does not cause rattling noise due to the fact that the rotational displacement is accompanied by an extremely soft torsional elastic displacement of about 120 ° and the presence of the plate member 30 in FIG. 8 or the spring 20 in FIG.

Next, V grooves 34 are equally spaced on the side surface of the outer ring 6 perpendicular to the rotation axis of FIG. 9 and the groove slopes are also formed on the side plate 50 (which corresponds to the side plate 9 of FIG. 8). A rolling medium ball 32 is interposed between the V grooves by a cage 33. The side plate 50 is placed with the screw 11 and the elongated hole 10 provided on the side surface of the output member 2 in FIG. According to FIG. 9, the ball rides on the slope with respect to the circumferential displacement 46 (backlash), and the axial force is increased by the axial displacement 45.

The present invention has the following inventive steps and effects over the background art described at the beginning.
In other words, just by loading a roller that is squeezed by a cage between a shaft having a simple conical surface and an outer ring raceway, an ultrahigh-pressure confined oil film is formed on the raceway surface, and its shear resistance and plastic deformation resistance Can transmit a powerful torque. Since all the rollers used participate in torque transmission, it has a huge torque capacity. Furthermore, since it is a self-holding clutch, it does not require any energizing energy such as electromagnetic, pneumatic, hydraulic, etc., and it saves energy. Also, when coupled, it absorbs rotational differences and impacts between the input and output shafts. After the connection, torque fluctuation and torque vibration on the input side are absorbed by the Hertz elasticity of the rolling element and the expansion elasticity of the raceway and are not transmitted to the output side.

Further, since the spring pressure of the preload can be minimized even at the permissible rotational speed, the resistance of the differential slip is negligible even when the meshing is always idle. Also, if the raceway surface is full-crowned close to a loose spherical surface, it is always meshed and the idling speed can be as high as 10,000 rpm. Even if the sliding contact part such as a spline is stuck due to rust or freezing due to a long-term stop, it functions reliably.

These are examples of the conventional Japanese Patent Laid-Open No. 05-149352. These are the external appearance schematic views which show the Example of Claim 1. FIG. 3 is an enlarged explanatory view of FIG. 2. , These are explanatory drawings of the movement of the axial force generation of the internal teeth and external teeth of the spline. FIG. 2 is a schematic diagram of forming a squeeze fluid film of dimples and oil. These are the arrangement | positioning cross-section explanatory drawing of the clearance of a splice. These are the arrangement | positioning explanatory schematic perspective views of a shear displacement promotion leaf | plate spring. These are explanatory drawings of axial force generation by interposing a ball in a V groove. Fig. 4 is a mounting explanatory view of a spline clearance extension spring. Is a diagram of the action of axial force generation and suction FIG. 4 is a layout view in which shear displacement promoting materials are stacked between spline teeth. These are the examples of the dimple molding of the shear displacement promoting member.

A representative embodiment will be described with reference to FIG. The inner and outer rings 1 and 6 and the roller 5 in FIG. 2 harden the bearing steel SUJ-2 to a quenching and tempering hardness HRC62 to 65. The surface of the track is ground to a roughness of 0.2 Ra. The track is basically a rotating hyperboloid, but it is sufficient that the inner and outer rings are elastically deformed by expansion and contraction, and the roller only needs to be in line contact with the track by a torque load.
The cage 18 is formed by press-molding the strip steel, or punching a pocket hole in the strip and rounding it to form an annular shape by welding. Further, it may be a resin molded product, and it conforms to the rolling bearing cage.
The output member 2 is carbon steel and is similarly heat-treated. A slip-promoting plate material 30 in FIG. 3 interposed between the spline gaps is formed by coining dimples on spring steel, and both ends are bent in opposite directions so that they do not come off the spline member. The surface roughness is smoothed by barrel polishing. The plate material may be coated with a low-μ material such as fluororesin, DLC, molybdenum disulfide, or graphite. Also, the plate material is laminated as shown in FIG. 11 to stabilize the shear displacement.
Since the distance of the relative displacement of the clutch is limited to 3 to 4 mm, the expansion / contraction sliding contact is not limited to the spline type, but protrudes in the axial direction like a dog clutch on the side surface of the inner and outer rings. The fitting of uneven teeth or the combination of pins and holes may be used. FIG. 2 is shown as a representative of the embodiment. However, the mating member with which the roller contacts may be anything such as the outer diameter of the hollow shaft, the inner diameter of the gear (not shown). The relative displacement may be smoothly performed.

Examples are shown in FIG. 2, FIG. 6, FIG. 5, FIG. 8, FIG. 9, FIG.

  The functions of this clutch are a one-way clutch that is always engaged and capable of high-speed overrunning, a torque limiter, a torsional damper for shock absorption, and a synchronized clutch with shock absorption, which requires hydraulic pneumatic pressure and electromagnetic force as auxiliary means. It is a self-holding clutch that does not, and has extremely high reliability. In addition, by appropriately selecting a lubricant, it can be a viscous fluid coupling with variable speed. For example, if the helicopter auto-rotation clutch is replaced with the invention, the reliability is improved. It is also used in power distribution devices for hybrid vehicles, differential limiting devices for 4WD vehicles, viscous fluid joints with variable speed, door closers, slow-down machines, etc.

1 ..Input side inner ring 2 ..Output housing 3 ..Output member connecting screw hole 4... Bearing 5 ..Roller 6 ..Outer ring 7 .. Retainer 9 .. Side plate cam 10. Set screw 12 ··· Cam slope 13 of side wheel · · Cam slope 14 of tip of spline teeth · · Female spline tooth 15 of output member · · Inner ring single leaf rotating hyperboloid 18 · · Cage 20 · · Clip spring 21 · · Spline · Lead angle 22 · · Biasing spring 23 · · Snap rings 24 and 25 · · Displacement direction 27 · · Flow direction 28 of squeeze fluid · · Dimple 29 · · Squeeze fluid film 30 · Displacement promoting plate 31 · · Outer ring 33 ·· Thrust ball cage 34 · Ball cam slope 35 on the outer ring side · Load torque 36 · Suction force 37 · Axial force end point 38 by ball · Suction force 3 by clutch engagement ·· Crunch engagement end point 40 · · Backlash range displacement 41 · · Preload spring biasing force · · 45 Axial displacement distance due to ball rolling · · Circumferential displacement distance due to ball rolling in the backlash range 47 .. Initial position of cam

Claims (3)

  In a clutch device comprising a plurality of rolling rollers squeezed by a cage between a conical surface of the inner ring outer diameter and a conical surface of the outer ring inner diameter, an angle with respect to a plane perpendicular to the rotation axis on the side surface of the inner ring or outer ring A roller clutch device that has an inclined surface that starts the relative displacement in the axial direction by an axial force generated by the contact of the inclined surface. A spring elastic member that restores the clearance of the relative displacement sliding surface of the clutch in a clutch device in which a plurality of rolling rollers squeezed by a cage are interposed between the conical surface of the inner ring outer diameter and the conical surface of the outer ring inner diameter A roller clutch device comprising: In a clutch device in which a plurality of rolling rollers squeezed by a cage are interposed between a conical surface of the inner ring outer diameter and a conical surface of the outer ring inner diameter, the relative displacement sliding distance between the inner ring and the outer ring due to torque load is the torque The above-mentioned two surfaces are set within a range in which the displacement of the oil between the acting surface and the pressure-receiving surface and the squeeze fluid film generated when the oil is discharged by the action of the torque can be lifted and displaced. A roller clutch device having a plate member coated with a low coefficient of friction material such as resin, molybdenum disulfide, graphite, diamond-like carbon or the like interposed therebetween.

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