JP3253426B2 - Power transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device used for a drive system of a vehicle.

[0002]

2. Description of the Related Art Conventional power transmission devices of this type include:
For example, JP-A-3-129149 and JP-A-63-163.
There is one described in Japanese Patent No. 285334.

[0003] The former conventional example is a center differential device for a vehicle, and a pair of left and right side gears 103 and 105 are rotatably arranged in a housing 101 to which torque is transmitted from an engine as shown in FIG. A front propeller shaft 107 is spline-coupled to the side gear 103, and a rear spline shaft 109 is spline-coupled to the right side gear 105.

[0004] In the housing 101, at least a pair of element gears 111 and 113 are provided.
3, 105 are arranged rotatably crossing the rotation axis. The element gears 111 and 113 include screw gears 111a and 113a and cooperating gears 111b and 111g, respectively.
113b, the screw gear portion 111a of one element gear 111 meshes with the screw gear portion 103a of the left side gear 103, and the other element gear 1
13 is the right side gear 10
5 is meshed with the screw gear portion 105a. Further, the coordinating portion 11 of the pair of element gears 111, 113
1b and 113b are in mesh with each other.

The left side gear 103 and the housing 101
Washers 115 and 117 are interposed between the right side gear 105 and the housing 1.
01 and the right side wall 101b.
1, and a washer 123 is also interposed between the opposing end surfaces of both side gears 103 and 105.

In this differential device, the driving torque from the housing 101 is reduced by the element gears 111 and 11.
3 to the left and right side gears 103 and 105.

That is, the element gears 111 and 113
From the screw gear portions 111a and 113a of the side gears 103 and 105, respectively.
For example, a frictional force is generated between the side gears 103 and 105 via the washer 123 by the axial component of the force applied to the side 105a, and the force between the side gear 105 and the right side wall 101b of the housing 101 via the washers 119 and 121. Are generated, and these frictional forces become differential limiting torque.

The latter conventional example is a rotation-difference-sensitive joint used as a driving force distribution device for a four-wheel drive vehicle or the like, and as shown in FIG. 6, a drive housing integrally formed with an input shaft. The drive housing 201 includes a rotor 203 integrally formed with the output shaft. The rotor 203 is rotatably inserted into a cam surface 205 formed on the inner peripheral surface of the drive housing 201.

The rotor 203 has a plurality of radial cylinder holes 207 formed therein.
Inside, a drive piston 209 is provided in an oil-tight state. These drive pistons 209 are in circumferential contact with the cam surfaces 205 of the drive housing 201, respectively, and reciprocate in the radial direction when the drive housing 201 and the rotor 203 rotate relative to each other.

Each drive piston 209 and cylinder hole 2
A cylinder chamber 211 is formed between the drive piston 207 and the cylinder chamber 211, and the volume of each of the cylinder chambers 211 changes as the drive piston 209 reciprocates.

Each cylinder chamber 211 is connected by an oil passage 213, and further connected to an accumulator chamber 217 through an orifice 215.

This rotation difference sensitive joint does not transmit torque when the input and output shafts are rotating at the same rotation speed, and when there is a rotation speed difference between the input and output shafts, the drive housing 201 and the drive housing 201 are not connected to each other. A relative rotation occurs with the rotor 203, and the drive piston 209 which is in contact with the cam surface 205 reciprocates in the radial direction due to the relative rotation, and the volume of the cylinder chamber 211 is reduced by being directed to the center of the rotation shaft in the reciprocation. At this time, the pressure in the cylinder chamber 211 increases due to the flow resistance caused by the orifice 215, and the hydraulic pressure obtained by multiplying the generated hydraulic pressure by the variable pressure area of the drive piston 209 becomes a force for pressing the driving piston 209 against the cam surface 205. Then, the torque on the input shaft side is transmitted to the output shaft side by this pressing force.

[0013]

However, in the former conventional example, the differential limiting torque is applied to the frictional force generated via the washer 123 interposed between the left and right side gears 103, 105 and the left and right side gears 103, 105. And the left and right side walls 101a and 101b of the housing 101 are provided by the frictional force generated through the washers 115, 117, 119 and 121, so that the torque transmission characteristics are reduced due to the friction of the washers 115 to 123 and the like. There was a fear.

In the latter conventional example, good torque transmission characteristics can be obtained, but there is a problem that the structure becomes complicated.

It is an object of the present invention to provide a power transmission device which has a simple structure and can further improve the torque transmission characteristics.

[0016]

According to a first aspect of the present invention, a case is provided between a relatively rotatable input / output shaft and a case connected to one of the input / output shafts. A sun gear of a helical gear connected to the other of the output shafts and rotatably disposed in the case, a working chamber formed between the case and the sun gear, and rotatable in the case
1st pinion of helical gear that is arranged at
A gear; and a first gear rotatably disposed in the case.
Second pinion gear of helical gear meshing with pinion gear
And the first and second pinion gears provided in the case
A pinion storage hole for storing the
The hydraulic oil flowing between the first and second pinion gears is
When the first and second pinion gears rotate while meshing with each other.
And a screw pump that discharges oil during the differential rotation of the input and output shafts. The screw pump compresses hydraulic oil in the working chamber by the screw pump, and controls the transmission torque according to the rotational speed difference between the two shafts by the hydraulic reaction force. It is characterized by doing.

[0017]

When the input / output shaft is differentially rotated, the hydraulic oil in the working chamber is compressed by the operation of the screw pump, and the transmission torque is controlled by the hydraulic reaction force.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a power transmission device according to a first embodiment of the present invention, and FIG. 2 is a perspective view showing an arrangement of sun gears.

The power transmission device 1 includes a sun gear 3, a plurality of pairs of first and second pinion gears 5 , 7 and a case 9.
Formed from pinion storage holes 21 and 23 provided in
It has a screw pump 37 and is disposed between the input shaft 11 and the output shaft 13 that can rotate relatively.

The case 9 comprises a case body 15 and a cover 17 having an outer edge integrally fixed to one end of the case body 15 by welding all around. A sun gear housing hole 1 for housing the sun gear 3 is provided inside the case 9.
9 and a pair of pinion housing holes 21 and 23 for accommodating the pair of first and second pinion gears 5 and 7 in the circumferential direction along the sun gear housing hole 19, for example, four pairs are formed at 90 ° intervals. ing. The sun gear housing holes 19 are arranged on the rotation axis and the peripheral surface of the case 9, and each pair of the pinion housing holes 21 and
Reference numeral 3 denotes a case 9 in which the rotation axis of the case 9 is arranged in parallel. Each of the pinion receiving holes 21 intersects with the sun gear receiving hole 19 in the axial direction, and the sun gear receiving chamber 19 and each of the pinion receiving holes 21 and 23, which intersect with the paired pinion receiving holes 23 in the axial direction, respectively. The storage chambers 19, 21 and 23 are sealed and filled with an appropriate fluid such as hydraulic oil.

The sun gear 3 is disposed in the sun gear housing chamber 19 coaxially with the rotation axis of the case 9 and is connected to one end of the input shaft 11.
The sun gear 3 is rotatably supported by the support recess 27 of the case main body 15 and the input shaft 11.
A seal member 29 is provided between the boss 25 and the input shaft 11.

The first pinion gear 5 has a pinion accommodation hole 21
Is rotatably fitted within the tooth tip, and both ends thereof are positioned on the left and right side walls of the case 9. The second pinion gear 7 is rotatably fitted in the pinion in the pinion receiving hole 23, and the right end is positioned on the right side wall of the case 9, and the left end is located in the receiving hole 23.
It is positioned by a positioning member 31 provided therein. The positioning member 31 has substantially the same length as the tooth width of the sun gear 3, and is fixed to the case body 15 via a locking portion 33.
Are formed.

The first pinion gear 5 has a pinion accommodation hole 21
Are meshed with the sun gear 3 in a region where they cross each other with the sun gear housing hole 19, and are also meshed with the second pinion gear 7 in a region where the pinion housing holes 21 and 23 cross each other.

The first pinion gear 5 is connected to the second pinion gear 7
The screw pump 37 is formed in the area a meshing with.

The sun gear 3 and the first and second pinion gears 5 and 7 are each formed by a helical gear, and have the same module, pressure angle, and twist angle factors.

The degree of fitting of the first and second pinions 5 and 7 with the pinion receiving holes 21 and 23 in the tooth tips is set densely for the purpose of generating friction torque. As the material of the fitting portion, it is preferable to use a material having high friction resistance, for example, a surface-hardened steel material or the like.

The friction torque can also be increased by increasing the surface roughness of the outer peripheral surfaces of the tooth tips of the first and second pinion gears 5 and 7 and the inner peripheral surfaces of the pinion receiving holes 21 and 23.

The case body 15 is formed with a bottomed spline hole 38 which is arranged coaxially with the rotation axis of the case 9 and opens to the right side wall. The output shaft 13 is spline-connected to the spline hole 38. I have.

Next, the operation of the first embodiment will be described.

The rotational force input from the input shaft 11 to the sun gear 3 is transmitted to the case 9 via the first pinion gear 5 and the second pinion gear 7, and is transmitted from the case 9 to the output shaft 13.

In the torque transmission performed in this manner, when a differential rotation occurs between the input shaft 11 and the output shaft 13, relative rotation occurs between the sun gear 3 and the case 9, and if the sun gear 3 Is rotated faster than the case 9, the first pinion gear 5 meshing with the sun gear 3 and the second pinion gear 7 meshing with the first pinion gear 5 also try to revolve in the same direction. However, since the rotation speed of the pinion housing holes 21 and 23 of the case 9 in the same direction is lower than the speed of the first and second pinion gears 5 and 7 trying to revolve,
The pinion gear 5 rotates while rubbing with the pinion housing hole 21, meshes while pushing the tooth surface with the second pinion gear 7, and the second pinion gear 7 also rotates while rubbing with the pinion housing hole 23.

At this time, the hydraulic oil in the working chamber 35 in the pinion receiving hole 23 is compressed by the action of the screw pump 37 formed in the area a where the first pinion gear 5 meshes with the second pinion gear 7, and The second pinion gear 7 is pressed in the axial direction by the hydraulic reaction force, and the first pinion gear 5 meshing with the second pinion gear 7 meshes with the sun gear 3 while pressing the tooth surface. Further, the first pinion gear 5 is a sun gear 3
The pinion receiving hole 21 is pressed against the inner peripheral surface of the pinion receiving hole 21 and the shaft end side surface portion 40 by the meshing reaction force, and accordingly, the second pinion gear 7 is also pressed against the inner peripheral surface of the pinion receiving hole 23 and the shaft end side surface portion 42. As a result, the friction torque increases. In addition, a plurality of sets of screw pumps can be driven by using the sun gear 3 as one rotation input member, and the pump action when relative rotation occurs due to differential rotation can be increased.

The rotation of the sun gear 3 is restricted by these actions, and the case 9 rotates as a reaction force.

Therefore, the transmission torque can be controlled in accordance with the difference between the rotation speeds of the input shaft 11 and the output shaft 13, and the torque transmission characteristics can be improved. Input shaft 11
The meshing reaction force of the sun gear 3 and the pinion gears 5 and 7 changes depending on the magnitude of the input torque to the gears, and the gears move as the axial thrust force and the pressing force against the housing hole, so that rotation control responsive to the torque can be performed. it can.

FIGS. 3 and 4 show a second embodiment of the present invention.

In this embodiment, the sun gear 3 is disposed substantially at the center of the case 39 in the axial direction, and a pair of screw pumps 41 and 43 are formed on both sides of the sun gear 3.

That is, the case 39 is the input shaft side case 3
9a and an output shaft side case 39b, both of which are fastened by bolts 45 or the like.

A sun gear housing hole 47 for housing the sun gear 3 is formed substantially at the center of the case 39 in the axial direction, and a pair of first and
A plurality of pairs of pinion receiving holes 53 and 55 for fitting the second pinion gears 49 and 51 are formed in the same direction. The pinion receiving hole 53 intersects the sun gear receiving hole 47 in the axial direction, and also intersects the pinion receiving hole 55 in the axial direction.

The first pinion gear 49 is provided in the pinion receiving hole 5.
3 is rotatably fitted within the tooth tip, and the central portion thereof is meshed with the sun gear 3 housed in the sun gear housing hole 47.

The second pinion gear 51 has a first gear portion 57 and a second gear portion 59. The second pinion gear 51 is rotatably fitted in the pinion receiving hole 55 in the tooth tip thereof, and the first gear portion 57 and the second gear portion. The portions 59 are in mesh with the first pinion gears 51, respectively.

The screw pump 41 is formed in an area b where the first gear portion 57 of the second pinion gear 51 and the first pinion gear 49 mesh with each other, and the second gear portion 59 and the first pinion gear 49 of the second pinion gear 51 are formed. Area c
A screw pump 43 is formed. The first pinion receiving hole 55 into which the second pinion gear 51 is fitted has the first
A connection section between the gear portion 57 and the second gear portion 59, that is,
An operating chamber 61 is formed in an area corresponding to the tooth width of the sun gear 3.

Accordingly, during the normal rotation of the input shaft 11 and the output shaft 13, for example, during normal rotation, the operation of one of the screw pumps 41 causes the working chamber 6 in the pinion housing hole 55 to operate.
The first hydraulic oil is compressed, and the first gear portion 47 of the second pinion gear 51 is pressed in the axial direction by the hydraulic reaction force. The first pinion gear 49 meshing with the first gear portion 47 meshes with the sun gear 3 while pressing the tooth surface. Is pressed against the inner peripheral surface of the pinion receiving hole 53 by the reaction force of engagement with the sun gear 3, and accordingly, the first gear portion 4 of the second pinion gear 51.
The seventh and second gear portions 49 are also pressed against the inner peripheral surface of the pinion receiving hole 55, and the friction torque increases.

During the reverse rotation, the working chamber 6 in the pinion receiving hole 55 is actuated by the action of the other screw pump 43.
The first hydraulic oil is compressed, and the second gear portion 49 of the second pinion gear 51 is pressed in the axial direction by the hydraulic reaction force, and the first pinion gear 49 meshing with the second gear portion 49 meshes while pressing the tooth surface of the sun gear 3. At the same time, the first gear portion 4 of the second pinion gear 51 is pressed against the inner peripheral surface of the pinion receiving hole 53 by the reaction force of engagement with the sun gear 3.
The seventh and second gear portions 49 are also pressed against the inner peripheral surface of the pinion receiving hole 55, and the friction torque increases.

Therefore, the torque transmission characteristics can be improved in any rotation axis direction.

Further, according to this embodiment, by changing the length of the sections b and c of the screw pumps 41 and 43, the torque transmission characteristics can be changed depending on the rotation direction.

In this embodiment, as in the first embodiment, a plurality of sets of screw pumps can be simultaneously driven to rotate by the one-rotation input member 11, and the pumping action when relative rotation occurs can be increased. Further, torque-sensitive differential control can be performed by each gear.

[0048]

As is apparent from the above description, according to the present invention, since the structure is simple and the transmission torque can be controlled in accordance with the rotational speed difference during the differential rotation, the torque transmission characteristics are improved. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing an arrangement of gears according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a perspective view showing an arrangement of gears according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a first conventional example.

FIG. 6 is a sectional view showing a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power transmission device 3 Sun gear 5,49 1st pinion gear 7,51 2nd pinion gear 9,39 Case 11 Input shaft 13 Output shaft 35,61 Working chamber 37,41,43 Screw pump

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-129149 (JP, A) JP-A-63-285334 (JP, A) JP-A-5-79519 (JP, A) JP-A-5-79519 99174 (JP, A) JP-A-4-15325 (JP, A) JP-A-3-265722 (JP, A) JP-A-3-246386 (JP, A) JP-A-59-226722 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16D 31/04, 31/06

Claims (1)

(57) [Claims] An input shaft that is rotatable relative to the input / output shaft;
A case connected to one of the input / output shafts and a case connected to the other of the input / output shafts and rotatably arranged in the case.
A helical gear sun gear, a working chamber formed between the case and the sun gear, and rotatably disposed in the case.
The first pinion gear of the helical gear meshed with the sun gear
And the first pini rotatably disposed in the case.
The second pinion gear of the helical gear that meshes with the on-gear,
The first and second pinion gears are provided in the case and housed therein.
A pinion receiving hole, the pinion receiving hole and the first,
The hydraulic oil flowing between the second pinion gear and the first
Discharge by rotating the second pinion gear
A screw pump that compresses hydraulic oil in the working chamber by the screw pump during differential rotation of the input and output shafts, and controls a transmission torque according to a rotation speed difference between the two shafts by a hydraulic reaction force of the screw pump. A power transmission device characterized in that: