JPH07149165A - Power transmission device - Google Patents

Abstract

PURPOSE:To provide a power transmission device with an accurate torque measurement function having high durability at a low cost. CONSTITUTION:A power transmission device is equipped with a power transmission mechanism 71 wherein driving force is transmitted between two of there gears 75, 81, 91 capable of rotating relatively when one of the three gears 75, 81, 91 is fixed, torque sensors 103, 105 and so on arranged on a fixed line member 93 containing a fixed gear 91 to convert distortion generated due to torque transmission to electric signals, and a controller 69 to calculate the transmission torque from the electric signals.

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 in a vehicle or the like.

[0002]

2. Description of the Related Art For example, when excessive torque is applied to a drive wheel on a slippery road surface, the vehicle idles and the behavior of the vehicle body becomes unstable.
In order to prevent such a situation and keep the maneuverability and stability of the vehicle high, traction control is performed in which the torque of the driving wheels is adjusted according to the road surface condition and steering conditions. At this time, if the torque on the drive wheel side can be directly measured, accurate and highly effective control can be performed.

Conventionally, in a four-wheel drive (4WD) vehicle in which the drive torque is estimated from the throttle opening or the drive is distributed to the front and rear wheels through a friction clutch, the friction clutch engagement force (for example, hydraulic pressure) is used to determine the drive force. It is difficult to achieve accurate traction control because the distribution ratio is estimated. Especially when a friction clutch is used, accurate control becomes even more difficult due to changes in frictional force.

FIG. 8 shows a technique disclosed in Japanese Unexamined Patent Publication No. 5-104966, in which the torque of the drive shaft 201 is detected by a torque sensor 203.

[0005]

However, the torque sensor for measuring the torque of the rotating system, which is used in the conventional example of FIG. 8, is generally expensive and delicate, and it produces a large vibration like a vehicle. It is difficult to use for the one to receive, and the error is large.

Therefore, an object of the present invention is to provide a power transmission device which has a low cost, a high durability, and an accurate torque measuring function.

[0007]

This power transmission device is one of first, second and third gears which can rotate relative to each other.
When a person is fixed, the driving force is transmitted between the other two persons, and a power transmission mechanism that applies a torque according to the transmission torque to the fixed gear side is arranged on the fixed system member including the fixed gear. The present invention is characterized by including a torque sensor that converts strain due to torque transmission into an electric signal, and a controller that calculates a transmission torque from the electric signal.

[0008]

If, for example, the first gear of the power transmission mechanism is fixed, the driving force of the engine is transmitted to the driving wheel side via the second and third gears and the fixing member including the first gear is Torque corresponding to the transmitted torque is applied and distortion occurs.
Therefore, the transmission torque can be accurately measured by converting the strain of the fixing member into an electric signal by a torque sensor such as a strain gauge to detect the strain and calculating the torque corresponding to the strain by the controller. Further, by using such a power transmission mechanism, torque measurement can be performed on a member of a fixed system, and a torque sensor that is inexpensive, resistant to vibration and highly durable can be used.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described with reference to FIGS. FIG. 1 shows this embodiment, and FIG. 3 shows a transfer using this embodiment. FIG. 4 shows a 4WD power system using this transfer. The left and right directions are the left and right directions of this vehicle, and the upper portions of FIGS. 1 and 3 correspond to the front of the vehicle. Members and the like without reference numerals are not shown.

As shown in FIG. 4, this power system includes an engine 1,
Transmission 3, transfer 5 of FIG. 3, front wheel side propeller shaft 7, front differential (front wheel side differential device), left and right front wheels 11, 13, rear wheel side propeller shaft 15, rear differential 17 (rear wheel side differential device). ), Left and right rear wheels 19, 21 and the like.

The driving force of the engine 1 is distributed from the transmission 3 to the front wheel side and the rear wheel side through the transfer 5 as described later, and the front wheels 11 and 13 are respectively transmitted via the front differential 9 and the rear differential 17. And distributed to the rear wheels 19, 21.

FIG. 3 shows a torque transmission shaft 2 which constitutes a shift lever 23 and a transfer 5 of the transmission 3.
5, multi-plate clutch 27, a pair of sprockets 29, 31
And a chain 33 connecting them, a power transmission device 35 of the embodiment, and the like.

The torque transmission shaft 25 is the transmission 3
Is connected to the output shaft of the transfer case 37, penetrates the transfer case 37 in the front-rear direction, and is supported by the transfer case 37 via bearings 39 and 41. The rear end of the torque transmission shaft 25 is connected to the rear wheel propeller shaft 1 via a flange 43.
It is connected to the 5 side.

The multi-plate clutch 27 is arranged between the clutch drum 45 and the hub 47. Clutch drum 45
Are fixed to the torque transmission shaft 25, the front end of the hub 47 is supported by the transfer case 37 by a bearing 49, and the rear end of the hub 47 is supported by the bearing 51.
Is supported by. Sprocket 2 on the outer circumference of hub 47
9 are spline-connected.

A hydraulic actuator 53 is provided at the rear end of the transfer case 37. Oil pressure is sent from the oil pump 55 to the hydraulic actuator 53 through the control valve 57, and the return spring 5
9 push rod 61, lever 63, bearing 6
5. The multi-plate clutch 27 is pressed and fastened via the pressing member 67. The control valve 57 is a controller 69
The opening degree of the multi-plate clutch 27 is adjusted by controlling the operating pressure of the hydraulic actuator 53. When the operation of the hydraulic actuator 53 is stopped, the return spring 59 releases the multi-plate clutch 27.

As shown in FIGS. 1 and 3, the power transmission device 35 is
It has a planetary gear mechanism 71 (power transmission mechanism) and a load cell 73.

As enlargedly shown in FIG. 1, the sprocket 31 is formed on an internal gear 75 of the planetary gear mechanism 71, and the internal gear 75 is attached to the transfer case 37 via bearings 77, 79. It is supported. Each shaft portion 83, 83 of the pinion gear 81
Is the front and rear pinion carrier 87 via the bush 85,
It is supported by 89. The front pinion carrier 87 is rotatably supported on the inner circumference of the internal gear 75, and is spline-connected to the propeller shaft 7 side of the front wheel.

The sun gear 91 (fixed gear) is splined to the fixed shaft 93 (fixed system member) of the load cell 73. The fixed shaft 93 penetrates the internal gear 75, and a bush 95 is arranged between the fixed shaft 93 and the internal gear 75.

When the multi-plate clutch 27 is engaged, the driving force of the engine 1 is input to the internal gear 75 of the planetary gear mechanism 71 via the sprocket 29, the chain 33, and the sprocket 31, and the speed is increased, whereby the front wheels 11, After being transmitted to the 13 side, the vehicle enters the 4WD drive state. Engaging force (slip) of the multi-plate clutch 27 by the hydraulic actuator 53
By adjusting the front wheels 11, 13 and rear wheels 19, 21
It is possible to control the driving force distribution ratio between them. Further, when the multi-plate clutch 27 is released, the vehicle enters the rear wheel drive state.

As shown in FIG. 1, the box 97 of the load cell 73 is fixed to the transfer case 37 with bolts 99, and the fixed shaft 93 is fixed to the box 97 with bolts 101. Further, as shown in FIG. 1, strain gauges 103 and 105 (torque sensors) are adhered to the outer periphery of the fixed shaft 93 so as to be orthogonal to each other and form 45 ° with respect to the center line 107 of the fixed shaft 93. Further, strain gauges 109 and 111 (torque sensors) are bonded to the back surface of the fixed shaft 93 in a state of being orthogonal to each other and forming an angle of 45 ° with respect to the center line 107.

These strain gauges 103, 105, 10
Reference numerals 9 and 111 are those in which an extremely thin electric resistor is attached to an insulating base. When the electrical low antibody is expanded due to the strain of the subject, the diameter becomes thin and the resistance value increases, and when the electrical low antibody shrinks, the diameter becomes large. As a result, the resistance value decreases and the amount of distortion is converted into an electric signal. In addition, strain gauges 103, 105, 109,
By arranging 111 at the angle as described above, each strain of tension, compression, and bending generated in the fixed shaft 93 is eliminated, and only the torsion strain is detected.

Strain gauges 103, 105, 109, 111
The resistance change of the strain gauges 103, 105, 10 is extremely small in order to extract this change as a voltage change.
Reference numerals 9 and 111 are connected to a bridge box 113 to form a Wheatstone bridge circuit each having four resistors. The output contact of this circuit is connected to the controller 69 via a lead wire 115.

When the planetary gear mechanism 71 is transmitting the driving force of the engine 1, a torsional moment corresponding to the transmission torque acts on the fixed shaft 93 via the sun gear 91, and a torsional strain is generated in the fixed shaft 93. Due to this torsional strain, the equilibrium state between the strain gauges 103, 105, 109, 111 is broken, and an unbalanced voltage corresponding to the amount of torsional strain is generated between the output contacts of the Wheatstone bridge circuit. This unbalanced voltage is used as a distortion signal from the load cell 73 by the controller 69.
Sent to.

The memory of the control 69 has a fixed shaft 9
A map for converting the transmission torque on the side of the front wheels 11, 13 from the torsional strain amount of No. 3 is written, and the drive torque of the front wheels 11, 13 is calculated from the received strain signal.

Thus, the controller 69 controls the front wheels 11,
While accurately monitoring the driving torque of No. 13, the fastening force of the multi-plate clutch 27 is controlled according to the road surface condition, the steering condition of the vehicle, the traveling condition, etc., and the driving force distribution ratio between the front and rear wheels is adjusted to an optimum value. As a result, the maneuverability of the vehicle is significantly improved.

Thus, the power transmission device 35 is constructed.

As described above, since the power transmission device 35 uses the planetary gear mechanism 71, it is possible to measure the transmission torque with a fixed system, and it is possible to accurately measure the torque. Further, the fixed type torque sensor is different from the rotary type torque sensor 203 used in the conventional example of FIG. 8 in that it is accurate and inexpensive, and is resistant to vibration, and accurate torque measurement is possible over a long period of time. It can be carried out.

Next, the second embodiment will be described with reference to FIG. The power transmission device 117 of this embodiment is also arranged in the transfer 119 of the 4WD vehicle. In FIG. 5 and the description of this embodiment, the same reference numerals are given to the members and the like having the same functions as the members and the like of the first embodiment. Further, members and the like without reference numerals are not shown.

The driving force of the engine 1 is transmitted from the transmission 3 to the rear wheel propeller shaft side via the torque transmission shaft 121 in the transfer 119. The sprocket 29 is fixed to the torque transmission shaft 121, and is connected to another sprocket 31 formed on the internal gear 75 of the planetary gear mechanism 71 by a chain 33.

Sun gear 91 of planetary gear mechanism 71
A multi-plate clutch 123 is disposed on the side, and the pinion carrier 87 is connected to the front wheel propeller shaft side via a shaft portion 125.

Clutch drum 12 of multi-plate clutch 123
7 (fixed system member) is fixed to the transfer case 129. The multi-plate clutch 123 is engaged by a hydraulic actuator 131 that operates by the oil pressure of the oil pump 55, the operating pressure of which is controlled by the control valve 57, and the controller 69 adjusts the opening of the control valve 57.

When the multi-plate clutch 123 is engaged, the driving force of the engine 1 is speeded up by the planetary gear mechanism 71 and transmitted to the front wheels to bring the vehicle into the 4WD state. When the multi-plate clutch 123 is released, the vehicle enters the rear wheel drive state. While the planetary gear mechanism 71 is transmitting the driving force, a twisting moment acts on the clutch drum 127 of the multi-plate clutch 123 via the sun gear 91 to give a strain.

A load cell 73 is provided on the clutch drum 127.
Is attached, the strain gauge (torque sensor) of the load cell 73 is bonded to the surface of the clutch drum 127,
The torsional strain is detected. The strain signal of the load cell 73 is sent to the controller 69. The controller 69 has a map for converting the transmission torque of the planetary gear mechanism 71 from the distortion amount of the clutch drum 127, and accurately detects the driving torque of the front wheels from the received distortion signal.

Thus, while accurately monitoring the driving torque of the front wheels, the fastening force of the multi-plate clutch 123 is controlled according to the road surface condition, the steering of the vehicle, the running conditions, etc., and the driving force distribution ratio between the front and rear wheels is optimized. It becomes possible to adjust to, and the maneuverability of the vehicle is significantly improved.

The power transmission device 117 configured as described above
In addition, the transmission torque can be accurately measured by the measurement in a fixed system, and the torque sensor used here is inexpensive, resistant to vibration and highly durable.

Next, the third embodiment will be described with reference to FIG. FIG. 6 shows a power system of a 4WD vehicle using the power transmission device 131 of this embodiment. In FIG. 6 and the description of this embodiment, the same reference numerals are given to the members and the like having the same functions as the members and the like of the first and second embodiments.

In this power system, the driving force of the engine 1 is transmitted from the transmission 3 through the transfer 133 to the propeller shaft 15 on the rear wheel side, and
It is transmitted to the propeller shaft 7 on the front wheel side via the chain transmission mechanism 135 of the transfer 133. The driving force on the rear wheel side is transmitted from the propeller shaft 15 to the rear differential 17 via the power transmission device 131, and the left and right rear wheels 19, 21 are
Will be distributed to. Further, the driving force on the front wheel side is transmitted from the propeller shaft 7 to the front differential 9 via the viscous coupling 137 and distributed to the left and right front wheels 11, 13.

In the planetary gear mechanism 71 of the power transmission device 131, the multi-plate clutch 143 is arranged between the clutch drum 141 (fixed system member) fixed to the differential carrier 139 and the internal gear 75. Driving force is input from the propeller shaft 15 to the sun gear 91, decelerated, and transmitted from the pinion carrier 87 to the rear differential 17.

The multi-plate clutch 143 is fastened to a hydraulic actuator 145 which is operated by the oil pressure of the oil pump 55,
The operating pressure is controlled by adjusting the opening of the control valve 57 performed by the controller 69.

When the multi-plate clutch 143 is engaged, the vehicle is in the 4WD state, and when the multi-plate clutch 143 is released, the vehicle is in the front wheel drive state. While the planetary gear mechanism 71 is transmitting the driving force, the internal gear 75
A twisting moment acts on the clutch drum 141 of the multi-plate clutch 143 via the pin to give a strain.

The load cell 73 is provided on the clutch drum 141.
Is attached, the strain gauge (torque sensor) of the load cell 73 is adhered to the surface of the clutch drum 141,
The torsional strain is detected. The distortion signal of the load cell 73 is sent to the controller 69 and the driving torque on the rear wheel 19, 21 side is calculated from the distortion amount of the clutch drum 141 by a built-in map.

In this way, while accurately monitoring the driving torque of the rear wheels, the engagement force of the multi-plate clutch 143 is controlled according to the road surface condition and the steering conditions of the vehicle to optimize the driving force distribution ratio between the front and rear wheels. It becomes possible to adjust the value, and the maneuverability of the vehicle is significantly improved.

The power transmission device 131 configured as described above
A fixed system allows accurate measurement of the transmission torque, and the torque sensor used here is inexpensive, resistant to vibration, and highly durable.

Next, a fourth embodiment will be described with reference to FIG. FIG. 7 shows a power system of a front wheel drive vehicle in which the power transmission device 147 of this embodiment is used. In FIG. 7 and the description of this embodiment, the same reference numerals are given to the members and the like having the same functions as the members and the like of the above-mentioned embodiments. The left and right directions are the left and right directions in this vehicle and FIG. 7, and members and the like without reference numerals are not shown.

In this power system, the engine driving force is transmitted from the clutch 149 and the transmission gear set 153 of the transmission 151 to the final gear 1 via the output gear 155.
Rotate 57. The internal gear 75 (fixed gear) of the planetary gear mechanism 71 is fixed to the transmission case 159. Final gear 15
The rotation of 7 is input to the sun gear 91 via the hollow shaft 161, is decelerated and is transmitted to the bevel gear type front differential 163 via the pinion carrier 87, and the front axles 165, 167 are then transmitted.
Is distributed to the left and right front wheels. At this time, a twisting moment corresponding to the transmitted torque acts on the internal gear 75 to cause distortion. Load cell 7 for internal gear 75
3 is attached, the strain gauge (torque sensor) of the load cell 73 is bonded to the outer peripheral surface of the internal gear 75, and the twist strain is detected. The strain signal of the load cell 73 is sent to the controller 69, converted into a transmission torque, and used for output control of the engine.

In this way, it becomes possible to control the output of the engine in accordance with the road surface condition and the steering traveling condition of the vehicle while accurately monitoring the driving torque, and the steerability of the vehicle is greatly improved.

The power transmission device 147 configured as described above
The transmission torque can be accurately measured by measuring with a fixed system, and the torque sensor used here is inexpensive, resistant to vibration, and highly durable.

The power transmission mechanism used in the present invention is not limited to the planetary gear mechanism used in each embodiment, but other types of power transmission mechanism generally called a differential gear mechanism can be used.

[0049]

According to the power transmission device of the present invention, when one of the first, second, and third gears that can rotate relative to each other is fixed, the power is transmitted between the other two gears. The transmission torque is measured by detecting the torsional strain generated on the fixed gear side of the mechanism. As described above, since the torque is measured by the fixed system, the torque can be accurately measured, and an inexpensive and highly durable torque sensor can be used, which is advantageous.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a front view of a strain gauge bonded to a back plate of a fixed shaft.

FIG. 3 is a sectional view of a transfer using the embodiment of FIG.

FIG. 4 is a skeleton mechanism diagram showing a power system of a vehicle using the transfer of FIG.

FIG. 5 is a skeleton mechanism diagram showing a second embodiment and a power system of a vehicle using the same.

FIG. 6 is a skeleton mechanism diagram showing a third embodiment and a power system of a vehicle using the same.

FIG. 7 is a skeleton mechanism diagram showing a fourth embodiment and a power system of a vehicle using the same.

FIG. 8 is a sectional view of a conventional example.

[Explanation of symbols]

35, 117, 131, 147 Power transmission device 71 Planetary gear mechanism (power transmission mechanism) 69 Controller 75 Internal gear (fixed gear) 91 Sun gear (fixed gear) 93 Fixed shaft (fixed system member) 103, 105, 109, 111 Strain gauge (torque sensor) 127, 141 Clutch drum (fixed system member)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01L 3/10 C

Claims (1)

[Claims] 1. A first, a second and a third which are rotatable relative to each other.
When one of the gears is fixed, the driving force is transmitted between the other two gears and a torque corresponding to the transmission torque is applied to the fixed gear side, and a fixed gear including the fixed gear. A power transmission device comprising: a torque sensor arranged on a system member for converting a strain due to torque transmission into an electric signal; and a controller for calculating a transmission torque from the electric signal.