JPH0366931A - power transmission joint - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a power transmission system in which, when transmitting the rotational power of a drive shaft to a driven shaft, the rotational power is transmitted in accordance with the difference in rotational speed between the two. Regarding the joint, it is particularly suitable for application to the power transmission system of a four-wheel drive vehicle.

[Conventional technology]

Conventional power transmission couplings, such as the center differential used in four-wheel drive vehicles, are made by meshing a screw-shaped worm with a large-diameter worm wheel that rotates at right angles to the worm. , a worm gear drive system that uses the irreversibility of the worm and worm wheel to perform differential and differential limiting (February 1, 1987, published by Sanei Shobo Co., Ltd. "Motor Fan J" issue, page 64), viscous drive system using a viscous coupling (see "Motor Fan" February 1987 issue, pages 76-78, published by Sanei Shobo Co., Ltd. on February 1, 1987), hydraulic type Torque split method that uses a plate clutch and electronically controls the hydraulic pressure supplied to this hydraulic multi-plate clutch (December 2, 1986, published by Railway Japan Co., Ltd., "All the 4 WD J Automotive Engineering No. 36") Vol. 14, No. 130-147), a hydraulic pump generates hydraulic pressure according to the speed difference between the input shaft and the output shaft, and this hydraulic pressure applies frictional force to suppress relative rotation, thereby generating power. There is a hydraulic pump system (see Japanese Patent Application Laid-open No. 63-284028) that performs transmission.

[Problem to be solved by the invention]

However, the above-mentioned worm gear drive system has problems in that it is difficult to machine the tooth surfaces of the worm and worm wheel, and it lacks durability due to large friction and wear. Since the transmitted torque depends on the viscosity of the oil, there is a problem that viscosity changes due to temperature changes have a large effect, and the torque split method also requires complicated structures such as hydraulic circuits and hydraulic control electronic circuits. The problem with the hydraulic pump method was that the bottom of the tank for the hydraulic pump and hydraulic circuit was complicated.

Therefore, the present invention has been made by focusing on the above-mentioned problems of the conventional example, and provides a power that can transmit power between a driving shaft and a driven shaft according to the difference in rotational speed between the two with a simple configuration. The purpose is to provide a transmission joint.

[Means to solve the problem]

The power transmission joint according to claim (1) is a power transmission joint that is interposed between a drive shaft and a driven shaft and transmits power according to the difference in rotational speed between the two. a screwing means having a screw shaft connected to one side and a screw member screwing into the screw shaft connected to the other side; It is characterized by comprising a power coupling means for changing the coupling force between the drive shaft and the driven shaft.

Further, in the power transmission joint according to claim (2), either one of the screw shaft and the screw member of the screwing means is slidably coupled in the axial direction to either the drive shaft or the driven shaft. It is characterized by being

Furthermore, the power transmission joint according to claim (3) is characterized in that the power coupling means is constituted by a wet multi-plate clutch to which a pressing force is applied by relative displacement of the screwing means.

[Effect]

In the power transmission joint according to claim (1), for example, the screwing means is a right-handed screw type, the drive shaft and the driven shaft rotate clockwise, and the screwing member of the screwing means is screwed onto the drive shaft. Assuming that the shafts are each connected to a driven shaft, when the driving shaft and the driven shaft have the same rotational speed, the relative movement position between the screw shaft of the screwing means and the screwing member is a neutral position. , the power coupling means constituted by a multi-disc clutch or the like is in a non-pressing state, and the drive shaft and the driven shaft are in a non-coupled state.

From this state, when the rotational speed of the drive shaft increases relative to the driven shaft, the screwing member of the screwing means moves from the neutral position according to the difference in rotational speed between the two, and the power coupling means accordingly shifts the relative displacement. A coupling force corresponding to the drive shaft is generated, and the rotational driving force of the drive shaft is transmitted to the driven shaft via the power coupling means, so that the rotation speed of the driven shaft is increased to match the rotation speed of the drive shaft.

As shown in 2, when the rotational speed of the driven shaft increases, the screwed member returns to the neutral position side, and when the rotational speeds of the drive shaft and driven shaft match, the relative position of the screwed member and the screwed shaft increases. The movement position returns to the neutral position, and the drive shaft and driven shaft become uncoupled.

Further, in the power transmission joint according to claim (2), either the screw shaft of the screwing means or the screwing member is slidably connected to either the drive shaft or the driven shaft in the axial direction. Therefore, the relative displacement of the screwing member is absorbed, and the distance between the drive shaft and the driven shaft can be kept constant without relative movement.

Furthermore, in the power transmission joint according to claim (3),
Since the power transmission means is composed of a wet multi-disc clutch, the multi-disc clutch is lubricated and cooled to prevent seizure and can withstand long-term use.

〔Example〕

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

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

In the figure, 1 is a drive shaft, and a driven shaft 3 is connected to this drive shaft 1 via a power transmission joint 2.

Here, the drive shaft 1 has a flange 1a at its right end,
The driven shaft 3 has a cylindrical portion 3b having serrations 3a formed on its inner circumferential surface and a mounting flange 3C formed at its right end.

The power transmission joint 2 has a screwing means 4 disposed between a drive shaft 1 and a driven shaft 3. This screwing means 4 includes a right-handed screw shaft 4a formed integrally with the drive shaft l, and a screw shaft 4a of
A cylindrical ball nut 1-4 as a screwing member to be screwed into the
b, and a large number of balls 4c interposed between the two so as to be able to circulate.
It consists of a ball screw 4d consisting of a ball nut 4
A shaft portion 4e is integrally formed at the right end of the shaft portion b, and this shaft portion 4e is fitted with serrations to the cylindrical portion 3b of the driven shaft 3 so as to be slidable in the axial direction.

Further, a cylindrical body 6 having serrations 6a formed on the inner periphery is fixed concentrically to the screw shaft 4a on the outer periphery side of the right side of the flange portion 1a of the drive shaft 1, and the right end of this cylindrical body 6 is the end. The oil seal 8 is closed by a plate 7 and is attached to the inner peripheral edge of the end plate 7 so as to contact the outer peripheral surface of the cylindrical portion 3b of the driven shaft 3.

Furthermore, a cylindrical body 9 having serrations 9a formed on its outer circumferential surface is fixed to the right end of the pole nut 4b and is concentrically arranged on the outside thereof.

A ring-shaped center pressure plate 10 is fitted into the axial center of the serrations 6a of the cylindrical body 6, and its axial movement is regulated by retaining rings 10a, 10b. Retaining rings 11a and llb are placed at both axial ends symmetrically across the center pressure plate 10 to prevent outward movement.
Pressure plate 11.11' regulated by
are fitted, and the center pressure plate 10 is further fitted.
and a multi-plate clutch 12a as a power coupling means between the pressure plates 11, 11' and both pressure plates 11,11'.

12b is interposed. These multi-plate clutches 12a,
12b each includes a plurality of drive plates 13 that fit into the serrations 6a of the cylindrical body 6, a plurality of driven plates 14 that fit into the serrations 9a of the cylindrical body 9,
It is composed of a friction plate 15 interposed between both plates.

Then, automatic transmission oil 16 is filled into the casing composed of the flange portion 1a, the cylindrical body 6, and the end plate 7.
Lubrication and cooling of the multi-disc clutches 12a and 12b is performed.

Next, the operation of the above embodiment will be explained. Assume now that the drive shaft l is rotated clockwise as shown by arrow A in FIG.

When the drive shaft 1 is started to rotate clockwise from the state where the drive shaft 1 and the driven shaft 3 have stopped rotating, the screw shaft 4a of the screwing means 4 is rotated.
is formed integrally with the drive shaft 1, the pole nut 4b advances toward the drive shaft 1, and the pole nut 4b
Since the cylindrical body 9 that is integrally fixed to the drive shaft 1 also moves forward toward the drive shaft 1, the breather plate 11' attached to this cylindrical body 9 and the cylindrical body 6 that is integrally fixed to the drive shaft 1 move forward. The distance i between the center pressure plate 10 and the center pressure plate 10, which is mounted such that its axial movement is restricted.

decreases, a pressing force acts on the multi-disc clutch 12b, and the rotational driving force of the drive shaft 1 is transferred to the flange portion 1a, the cylindrical body 6, the center pressure plate 10, the multi-disc clutch 12b, and the pressure play) 11'. , the cylindrical body 9 and the ball neck) 4b to the driven shaft 3, so the driven shaft 3 starts rotating. At this time, the ball nut 4b moves in the axial direction, but since the shaft portion 4e of the pole nut 4b and the driven shaft 3 are serration-fitted, the driven shaft 3 does not move in the axial direction.
Therefore, the drive shaft 1 and the driven shaft 3 do not move relative to each other, and the power transmission joint 2 can be installed reliably and easily.

When the rotational speed of the driven shaft 3 increases and the rotational speed difference with the drive*kl decreases, the pole nut 4b retreats toward the driven shaft 3, and the pressing force on the multi-disc clutch 12b gradually decreases. Therefore, the engagement force of the multi-disc clutch 12b gradually decreases, and the power transmitted to the driven shaft 3 decreases.

After that, when the drive shaft 1 and the driven shaft 3 reach a constant velocity state, the ball nut 4b becomes the neutral position, and the multi-disc clutch 12
Since the pressing force on a and 12b becomes zero, these multi-plate clutches 12a and 12b become unengaged, power transmission between the drive shaft 1 and the driven shaft 3 is cut off, and the drive shaft 1 and the driven shaft 3 become uncoupled.

On the other hand, when the drive shaft 1 is rotated counterclockwise and the rotation speed of the drive shaft 1 is higher than the rotation speed of the driven shaft 3, the ball nut 4b moves back from the neutral position by a distance corresponding to the rotation speed difference, and As a result, a pressing force is applied to the multi-disc clutch 12a and the multi-disc clutch 12a is brought into the engaged state, whereby the rotational driving force of the drive shaft l is transmitted to the driven shaft 3, and the driven shaft 3 is rotationally driven, and the difference in rotational speed between the two is reduced. When the amount decreases, the -pole nut 4b moves to the neutral position, and the pressing force of the multi-disc clutch 12a is released, thereby cutting off power transmission between the drive shaft 1 and the driven shaft 3.

After all, when there is a difference in rotational speed between the drive shaft 1 and the driven shaft 2, power is transmitted between the drive shaft 1 and the driven shaft 2 in a direction that eliminates the difference in rotational speed between the two, and both When the vehicle is in a constant velocity state, power transmission is cut off.

In the above embodiment, a case has been described in which the screw shaft 4a and the cylindrical body 6 are connected to the drive shaft 1, and the ball neck 4b and the cylindrical body 9 are connected to the driven shaft 3, but the present invention is not limited to this. Instead, drive shaft 1 is the driven shaft, and driven shaft 3 is the driven shaft.
may be used as the drive shaft.

In addition, in the above embodiment, the center pressure plate 10 is disposed on the cylindrical body 6 that does not move in the axial direction to restrict axial movement, and the cylindrical body 9 that moves in the axial direction is provided with a pleasure plate (11.11). Although the description has been made on the case where the pressure plates 11 and 11' are provided on the cylindrical body 6, the pressure plates 11 and 11' may be provided on the cylindrical body 6, and the center pressure plate 10 may be provided on the cylindrical body 9.

Further, in the above embodiment, the case where the drive shaft 1 rotates in forward and reverse directions has been described, but if the drive shaft 1 is rotationally driven in only one direction, one of the multi-disc clutches 12a and 12b may be omitted. You can do it like this.

Furthermore, the connection means between the pole nut 4b and the driven shaft 3 is not limited to serration fitting, and various connection means such as a spline connection, a linear ball bearing, a constant velocity bolt, a rubber coupling, etc. can be applied, and The screw shaft 4a may be slidable in the axial direction of either the drive shaft 1 or the driven shaft 3, and the pole nut 4b may be fixed to the other.

Furthermore, the screwing means 4 is not limited to the configuration of a ball screw, and square screws, triangular screws, etc. can be applied.

Next, a first embodiment in which the power transmission joint 2 according to the present invention is applied to a power transmission system of a vehicle will be described with reference to FIG.

In this first embodiment, the present invention is applied to a full-time four-wheel drive vehicle based on a front-mounted engine front-wheel drive vehicle, and as shown in FIG. Front wheel side final reduction gear 23 via transmission 22
from the final reduction gear 23 to the front wheels 24. On the other hand, the front wheel final reduction gear is connected to the rear wheel 25! The rotational driving force of the output shaft of a transfer 26 connected to The signal is connected to the rear wheel side final reduction gear 29 via the rear wheel side final reduction gear 29, and is transmitted from this final reduction gear 29 to the rear wheels 25.

The operation of this second embodiment will be explained. Low I! ! Friction coefficient road (
For example, when a vehicle starts or accelerates on a rough road, frozen road, or rainy road, slipping may occur between the front wheels 24, which are driving wheels, and the road surface. At this time, the rotational speed of the front wheels becomes faster than the rotational speed of the rear wheels, so the rotational speed of the propeller shaft 27 becomes faster than the rotational speed of the propeller shaft 28. Therefore, as described above, when the pole nut 4b of the power transmission joint 2 moves forward, the driving force of the propeller shaft 27 is transmitted to the propeller shaft 28 via the multi-disc clutch 12b, and the rear wheel 25 is rotationally driven. When the vehicle enters a driving state and then enters a constant speed running state, when a difference in rotational speed occurs between the front wheels 24 and the rear wheels 25, power is transmitted by the power transmission joint 2 to eliminate this difference.

As mentioned above, when driving on a road with a low friction coefficient such as a snowy road, frozen road, or rainy road, wheel spin will occur in the front wheels 24, which are the driving wheels, even when the vehicle is running at a constant speed. Similarly, the rotational speed of the front wheel 24 is the same as that of the rear wheel 25.
The rotational speed becomes faster than the rotation speed of , and power is distributed to the rear wheels 25 via the power transmission joint 2, thereby improving steering stability.

Furthermore, when engine braking is applied while the vehicle is traveling downhill, the rotational speed of the front wheels 24 first becomes slower than the rotational speed of the rear wheels 25. Therefore, when the ball nut (4b) of the power transmission joint 2 retreats from the neutral position, a pressing force acts on the multi-disc clutch 12a, and the clutch 12a is brought into the engaged state, thereby connecting the propeller shaft 27 and the propeller shaft 28. In this state, engine braking is also applied to the rear wheels 25, and the engine braking effect can be improved.

In this way, in a four-wheel drive vehicle, by installing the power transmission joint according to the present invention, power is transmitted so that the difference in rotational speed between the front and rear wheels is eliminated, so that tire wear is reduced between the front and rear wheels. This makes it possible to reduce energy loss, improve riding comfort, and alleviate the tight corner braking phenomenon that occurs when turning with a small turning radius during low-speed driving.

As described above, it is possible to distribute the driving force between the front wheels and the rear wheels according to the road surface conditions without requiring a complicated control circuit.

Next, a second embodiment in which the power transmission joint according to the present invention is applied to a vehicle will be described with reference to FIG.

In this second embodiment, the present invention is applied to a full-time four-wheel drive vehicle based on a front engine rear wheel drive vehicle, and as shown in FIG. A transfer 33 that distributes the driving force to the front and rear wheels is connected to the output side of the transfer 32, and the output shaft for the rear wheels of this transfer 33 is connected to the final reduction gear for the rear wheels 35 via the propeller shaft 34, and the output shaft for the front wheels is connected to the drive shaft 1 of the power transmission joint 2 according to the present invention, the driven shaft 3 of the power transmission joint 2 is connected to the front wheel final reduction device 36, and the output shaft of the rear wheel final reduction device 35 is connected to the rear wheel 37. In addition, the output shaft of the front wheel side final reduction gear 36 is connected to the front wheel 38.

According to this second embodiment, when there is no difference in rotational speed between the front and rear wheels, the rear two-wheel drive state is established, and the rear wheels are in an acceleration state or a deceleration state, or slippage occurs between the rear wheels and the road surface, causing the front and rear wheels to have rotational speeds. When a difference occurs, the driving force is distributed to the front wheels, resulting in a four-wheel drive state, and the same effects as in the first embodiment can be obtained.

Next, a third embodiment in which the present invention is applied to a power transmission system of a vehicle will be described with reference to FIG.

This third embodiment is an application of the present invention to a part-time four-wheel drive vehicle in which a two-wheel drive state and a four-wheel drive state can be selected, and as shown in FIG. The configuration is the same as that in FIG. 2, except that a dog clutch 42 is provided in the transfer 26 to switch between four-wheel drive and two-wheel drive by operating a shift rod 41. Corresponding parts are given the same reference numerals, and detailed description thereof will be omitted.

According to this third embodiment, when four-wheel drive is selected by the dog clutch 42, the same four-wheel drive state as in the first embodiment is achieved, and the power transmission joint 2 eliminates the rotational speed difference between the front and rear wheels. Drive force is distributed to the rear wheels, and when two-wheel drive is selected, power transmission to the rear wheels is cut off, resulting in a front-wheel drive state similar to a normal front-wheel drive vehicle.

Note that the power transmission format of a four-wheel drive vehicle to which this invention can be applied is not limited to the first to third embodiments described above.
It can be applied to any type of four-wheel drive vehicle, such as a rear-mounted engine type four-wheel drive vehicle or a midship engine type four-wheel drive vehicle.

Further, in the first to third embodiments described above, the case where the power transmission joint according to the present invention is applied to the power transmission system of a vehicle has been described, but the invention is not limited to this.
When a difference in rotational speed occurs between a drive shaft and a driven shaft, it can be applied to equipment that requires power transmission between the two in accordance with the difference in rotational speed.

〔Effect of the invention〕

As described above, according to the power transmission joint according to claim (1), the screwing means interposed between the driving shaft and the driven shaft, and the driving shaft and the driven shaft depending on the relative displacement amount of the screwing means. With a simple configuration that includes a power fastening means that changes the fastening force so as to generate a coupling force with the shaft, the transmission between the drive shaft and the driven shaft is performed according to the rotational speed difference between the drive shaft and the driven shaft. The power can be accurately controlled mechanically and automatically, and unlike the viscous coupling system, there is no operational instability such as temperature dependence, and the system uses a worm gear drive system and hydraulic pump. Effects can be obtained without requiring complicated configurations like power distribution devices and torque split systems.

Further, according to the power transmission joint according to claim (2), either the screw shaft or the screw member constituting the screw means is slidably connected to the drive shaft or the driven shaft. Since the relative displacement of the coupling means can be absorbed and the distance between the drive shaft and the driven shaft does not change, the power transmission joint can be mounted reliably and easily.

Furthermore, according to the power transmission joint according to claim (3), since a wet multi-disc clutch is applied as the power coupling means, the multi-disc clutch can be lubricated and cooled by the enclosed oil, and the multi-disc clutch can be cooled with the enclosed oil. This has the effect of preventing the clutch from seizing and making it durable for long-term use.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIGS. 2 to 4 are line configuration diagrams showing embodiments in which the power transmission joint of the present invention is applied to a four-wheel drive vehicle. . DESCRIPTION OF SYMBOLS 1... Drive shaft, 2... Power transmission joint, 3... Driven shaft, 4... Screwing means, 4 a-... Screw shaft, 4b...
Pole nut (screwing member), 4d...Ball screw, 6
... Cylindrical body, 9... Cylindrical body, 10... Center pressure plate, 11. ．． 11'...Pressure plate, 12a, 12b...Multi-plate clutch (power coupling means). Figure 2

Claims (3)

[Claims] (1) In a power transmission joint that is interposed between a drive shaft and a driven shaft and transmits power according to the difference in rotational speed between the two, a screw shaft connected to either the drive shaft or the driven shaft; , a screwing means having a screw shaft connected to the other and a screwing member screwed together, and a coupling force between the driving shaft and the driven shaft according to relative movement of the screw shaft and the screwing member of the screwing means. A power transmission joint characterized in that it is equipped with a power coupling means for changing. (2) The power according to claim (1), wherein either one of the screw shaft and the screw member of the screwing means is slidably connected in the axial direction to either one of the drive shaft and the driven shaft. transmission joint. (3) The power transmission joint according to claim 1 or 2, wherein the power coupling means is constituted by a wet multi-disc clutch to which a pressing force due to relative displacement of the screwing means is input.