JPH03204438A - Torque detector for continuously variable transmission - Google Patents

Abstract

PURPOSE:To make a detector excellent in durability with no fear of noise by providing a sensor for pressure contact force between mutual speed change elements, in an uncontinuously rotating member which is subjected to axial thrust caused by a thrust mechanism installed around a gear shaft. CONSTITUTION:Torque is transmitted to a primary sheave shaft 31a via a forward-backward change gear, and transmitted from a fixed cam flange 61a via a roller 63a to a thrust cam 62a which is mounted on the end face of a fixed sheave 31b, in which axial force occurs. Such force is transmitted to a V-belt 33, a variable sheave 31c, a thrust ball bearing, a variable speed collar 99 and a guide sleeve 102a. Compressive force is loaded on a pressure sensor 301a between a flange 101a, supporting the primary sheave shaft 31a via the thrust ball bearing, and the guide sleeve 102a. The same form applies to a secondary sheave shaft 32a. Sensor signals are guided to the outside of a case 10 through a signal line 302a.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a torque detection device for a continuously variable transmission, and more particularly to a torque detection device for detecting input/output torque in a continuously variable transmission.

[Conventional technology]

One type of continuously variable transmission is a belt-type continuously variable transmission (hereinafter referred to as CVT). Since this transmission is capable of transmitting large torque, it is used as a transmission part of an automatic transmission for a vehicle.

An example of an automatic transmission for a vehicle using such a continuously variable transmission is disclosed in Japanese Unexamined Patent Publication No. 1-153856. This device is equipped with a fluid transmission device as a starting device, a dual planetary gear device as a forward/reverse switching device, and a CVT as a continuously variable transmission. Each of these devices is controlled by an electronic control device (
Control is based on commands from the ECU (hereinafter referred to as the ECU).

In the shift control in the CVT described above, when controlling with maximum power, the target torque ratio is set so that the rotation speed has the highest horsepower at the actual engine throttle opening of the vehicle.

To find the highest horsepower, the engine's output torque (
It is essential to detect CVT input torque or output torque) and engine rotational speed, and conventional detection methods have adopted a configuration in which a strain gauge is attached to a rotating shaft for detection.

[Problem to be solved by the invention]

However, in the conventional input/output torque detection device as described above, a strain gauge is attached to a continuously rotating shaft to detect torque. In order to transmit a signal from one part to a fixed part, a slip ring was used, or a signal extraction device was required to transmit the signal after FM modulation.

In devices that use slip rings in this way, there are problems such as the generation of noise from the sliding parts of the slip rings and wear of the sliding parts, and even in devices that use FM modulation, the signal is affected by noise. There are problems such as a large measurement error due to the influence, and there are problems in terms of reliability and cost.

In view of these circumstances, an object of the present invention is to provide a torque detection device for a continuously variable transmission that is free from noise generation and has excellent durability.

Another object of the present invention is to provide a torque detection device that does not require special space for installation.

A further object of the present invention is to provide a torque detection device that can detect torque with high accuracy.

Another object of the present invention is to provide a torque detection device capable of detecting the input/output torque of a continuously variable transmission using the axial thrust generated by the operation of the V-belt clamping mechanism.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a torque detection device for a continuously variable transmission that generates pressure contact force between transmission elements using a thrust mechanism provided around a transmission shaft.
The present invention is characterized in that a discontinuously rotating member that receives a force generated in a mechanical portion of the continuously variable transmission due to the operation of the thrust mechanism is provided with a sensor that detects stress applied to the member.

The present invention also provides a torque detection device for a continuously variable transmission in which a pressing force between transmission elements is generated by a thrust mechanism provided around the axis of a transmission shaft, in which a non-continuous transmission receives an axial thrust generated by the thrust mechanism. It is characterized in that a pressure sensor is provided between the rotating members.

The pressure sensor may be a load cell having a strain gauge attached to an annular strain body.

Further, a large number of the strain gauges may be arranged along the circumference of the strain body.

Further, the present invention provides a primary sheave provided on the input shaft, a secondary sheave provided on the output shaft, a V-belt interposed between the primary sheave and the secondary sheave, and a primary sheave provided on the input shaft, the primary sheave, and the output shaft. In a torque detection device for a continuously variable transmission equipped with a V-belt clamping mechanism using a thrust mechanism interposed between a shaft and a secondary sheave, a discontinuous torque detection device that receives the axial thrust generated by the operation of the V-belt clamping mechanism in opposition to each other. It is also possible to interpose a pressure sensor between each rotating member and lead out the signal line of the pressure sensor to the outside of the case of the continuously variable transmission so that the input shaft torque and the output shaft torque can be detected.

[Action and effect of invention]

In the device according to the present invention having such a configuration,
The sensor installed on the non-continuously rotating member can detect the stress generated in the mechanical part of the continuously variable transmission caused by the thrust mechanism and send the signal through the signal line, so it can be used to extract signals from slip rings, FM modulation, etc. It is possible to provide a torque detection device that does not require a device, is free from noise generation, and has excellent durability.

Further, if the pressure sensor is a load cell having a strain gauge attached to an annular strain body, it is possible to provide a torque detection device that does not require space.

Further, by arranging a large number of strain gauges along the circumference of the strain body, it is possible to provide a torque detection device that can detect with high accuracy.

In a torque detection device for a continuously variable transmission equipped with a V-belt clamping mechanism using a thrust mechanism, pressure sensors are interposed between discontinuously rotating members that face each other and receive the axial thrust generated by the operation of the V-belt clamping mechanism. However, if the signal line of the pressure sensor is led outside the case of the continuously variable transmission, the input/output torque of the continuously variable transmission can be detected using the axial thrust generated by the operation of the V-belt clamping mechanism. It is possible to provide a possible torque detection device.

〔Example〕

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

FIG. 2 is an exploded cross-sectional view showing the entire automatic transmission including a CVT. As shown in the figure, this device includes a torque converter 12 with a lock-up clutch 12 as a starting device 1, and a turbine 12a thereof. A dual planetary planetary gear system 2 as a forward/reverse switching device whose output is input to the sun gear 21 and whose output from the carrier 22 is input to the primary sheave 31.
1 and a secondary sheave 32 parallel to the CVT 3 as a continuously variable transmission device that performs stepless speed change using sheaves 31 and 32 and a V belt 33, and the output of the CVT 3 is differentially variable via a counter gear 4. The signal is configured to be output to the dynamic gear mechanism 5. A forward clutch 23 consisting of a multi-disc clutch is interposed between the carrier 22 and the sun gear 21 of the dual planetary gear system 2, and a multi-disc brake is also disposed between the ring gear 24 and the transmission case IO. When the forward clutch 23 is engaged, the sun gear 21 and the carrier 22 are directly connected, and when the reverse brake 25 is activated, the ring gear 24 is fixed and the planetary gear 26 revolves as the carrier 22 reverses. taken out,
The output rotation is transmitted to the primary sheave shaft 31a as an input shaft of the continuously variable transmission at a gear ratio of approximately 1:1 in forward and reverse directions.

Incidentally, riding roller cam type thrust mechanisms 6a and 6b are provided between the carrier 22 and the fixed sheave 31b in this transmission, and between the secondary sheave shaft 32a as an output shaft and the fixed sheave 32b. The thrust mechanism consists of a cam flange 61a fixed to the primary sheave shaft 31a (see also FIG. 1 showing an enlarged view of the CVT section for details), a cam plate 62a fixed to the fixed sheave 31b, and a cam plate 62a fixed to the fixed sheave 31b. The cam surface of the cam flange 61a and the cam plate 62a facing each other is formed by repeating peaks and valleys at a constant period in the circumferential direction, and usually has a plurality of rollers 63a interposed therein. If each of the rollers 63a is located in a trough between two mountains, or if relative torsion occurs between the cam flange 61a and the cam plate 62a, the rollers 63a will move in the direction of running onto the peak. This acts to increase the distance between the two cam surfaces. This force acts as a force that presses the fixed sheave 31b toward the movable sheave 31c, and its magnitude increases depending on the relative amount of tear between the cam flange 61a and the cam plate 62a. Exactly the same effect occurs on the secondary sheave shaft 32a side. Note that on the secondary sheave shaft 32a side, the only difference is that the arrangement of each member is reversed and that a gear that meshes with the counter gear 4 is used as a member that presses the thrust ball bearing, so the corresponding members are different. The explanation will be made by replacing a with b in the illustration. In this way, the thrust load according to the torque is fixed to the sheave 31b,
32b, the pressure contact force between the primary sheave 31 and the V-belt 33 and between the V-belt 33 and the secondary sheave 32 constituting the transmission mechanism is increased or decreased according to the load to prevent slippage between them. It is taken.

In the figure, what is attached to the upper part of this device is a speed change motor 7 of the CVT 3, and the rotation of this motor 7 is transmitted to the counter shaft 7b by a speed change motor 7 via a reduction gear 7a.
A transmission collar 9a is transmitted to two gears 7c and 7d and further supported by a transmission case 10 via ball screw mechanisms 8a and 8b.

This will be communicated to 9b. And this shift collar 9a.

Movement in the axial direction accompanying the rotation of 9b is transmitted to movable sheaves 31c and 32c via ball bearings.

Therefore, these elements constitute an actuator section that operates the transmission mechanism. In this device, the movable sheaves 31c, 32 are moved by the operation of the actuator section.
c is fixed sheave 31b and fixed sheave 32b during speed change operation.
They slide in opposite directions along their respective axes, and when the V-groove of the primary sheave 3I expands and the V-groove of the secondary sheave 32 contracts, it becomes the deceleration position, and in the opposite case, it becomes the speed-up position. , a speed change is performed by changing the engagement position between the V-belt 33 and the sheave 31, 32.

FIG. 1 is an enlarged cross-sectional view showing the CVT 3 of this transmission. A pressure sensor 301a is interposed between the end face of the flange 101a and the end face of the guide sleeve 102a, which engages with the slit of the flange 101a with a claw and is non-rotatably engaged. Similarly, a flange 101 is a discontinuously rotating member that supports the end face of the secondary sheave shaft 32a via a thrust ball bearing.
A pressure sensor 301b is interposed between the end face of the sleeve 102b and the end face of the sleeve 102b, which engages with the slit of the flange 101b with a claw so as not to rotate. And flange 101a.

Since the flange 101b is non-rotatably supported by the case 10, these flanges 101a, 1o1b and the sleeve 1
02a and 102b are members that do not rotate with respect to the case 10.

In the torque detection device configured as described above, torque is transmitted to the primary sheave shaft 31a via the dual planetary planetary gear device 2 as a forward/reverse switching device. This torque is applied from a cam flange 61a fixed to the primary sheave shaft 31a, through a roller 63a, to a thrust cam 62a attached to the end face of the fixed sheave 31b.
This force is transmitted to the V-belt 33, movable sheave 31c, thrust ball bearing,
It is transmitted to the speed change collar 9a and the guide sleeve 102a.

Therefore, as shown by the thick line in the figure, the axial force generated by the thrust mechanism 6a is
A closed loop that generates a pressing force is formed between the flange 101a of O and the guide sleeve 102a,
A compressive force is applied to the strain body of the pressure sensor 301a interposed in the loop.

On the other hand, on the side of the secondary shaft 32a, the torque transmitted to the V-belt 33 is applied to the cam plate 62 via the fixed sheave 32b.
b, and is transmitted to the cam flange 61k by the roller 63b.
) to the left, and this thrust causes the secondary shaft 32a, the gear meshing with the counter gear, the thrust ball bearing, the flange 101b,
The force is transmitted to the variable sheave 32c via the pressure sensor 301b, the guide sleeve 102b, the speed change collar 9b, and the thrust ball bearing, forming a closed thrust loop. Therefore, in this case as well, compressive force is applied to the strain body of the pressure sensor 301b interposed in the loop.

FIG. 3 is a partially enlarged view of this device showing in detail the arrangement of the pressure sensor 301a on the primary sheave side and the pressure sensor 301b on the secondary sheave side. The signal lines 302a and 302b that output the signal are led out of the case through holes 105a and 105b that penetrate the outer wall of the case 10, and seals 106a and 106b made of silicone rubber or the like are attached to the outer ends of the holes 105a and 105b. It has been subjected. This prevents leakage of lubricating oil and intrusion of dust through the holes 105a and 105b, and also prevents the signal lines 302a and
This is for fixing 302b in place.

FIG. 5 is a perspective view showing the structure of the pressure sensors 301a, 301b. As shown in the figure, the pressure sensors 301a, 301b are arranged on the inner peripheral surface and the outer peripheral surface of the annular strain body G. It is configured as a load cell R with strain gauges R1 to R4 attached in the axial direction and the circumferential direction, respectively.

FIG. 6 is a circuit diagram showing the connection of gauges R1 to R4. As shown in the figure, each gauge is connected in a well-known bridge connection, and between gauge R1 and gauge R2 and between gauge R3 and gauge R4. The power supply voltage E0 is applied between, and the gauge R
1 and gauge R2 and between gauge R2 and gauge R3. Note that the output obtained by such a connection has a gauge factor of K
, Poisson's ratio is σ, and the load due to axial force is F
, the area of the end face of the flexure element is S, and the modulus of longitudinal elasticity of the flexure element is E, then -L °C 2° - ° -2° ``SE''.

Fig. 7 is a graph showing the relationship between the load Fp applied to the primary sheave and the input torque T1□. Such load F.

By detecting input torque T4. ．． It is possible to know.

A similar relationship holds on the secondary sheave side, and the load F applied to the secondary sheave and the output torque T, 1 in Fig. 8
, the output torque T a II 1 can be determined from the load Fs applied to the secondary sheave, as shown in the graph showing the relationship between .

As explained above, the torque detection device of this embodiment is
Flanges 1o1a, 101b, and sleeve 102a are discontinuously rotating members that receive the force in opposition by utilizing a mechanism that generates axial force by thrust mechanisms 6a and 6b and applies clamping force to sheaves 31 and 32.
, 102b, the pressure sensors 301a, 301b
Since the pressure sensor 301 is detected by
a. Highly accurate torque detection is possible because no equivalent special means is required to take out the signal from 301b to the outside of the transmission case 10, and there is no risk of noise being generated or mixed in by the means for taking out. You will be able to obtain the following effect.

Next, FIG. 9 is a perspective view of a pressure sensor showing another embodiment of the present invention. Holes G, ~G, are provided.

FIG. 1O is an enlarged perspective view of the X section in FIG. Gauge R1
, R3 in the axial direction, and the gauge RL
R4 is installed in the radial direction. With this arrangement, the gauge output e can be calculated by processing the output e1 of each gauge group as follows, for example, 8=upward e, l-1, so that the detected values can be averaged. It becomes possible to obtain the effect that the stress applied to the body can be detected well around the circumference.

Although the present invention has been described in detail based on an example in which the present invention is applied to a CVT, the present invention is also applicable to other continuously variable transmissions, and is not limited to the above-mentioned example. It goes without saying that the invention can be implemented by changing the specific details of the invention in various ways within the scope of the claims. For example, it is possible to select a member that rotates reciprocatingly as a non-continuously rotating member that receives the axial thrust generated by the thrust mechanism. In that case, the signal line should be led out of the case with enough room to allow the member to rotate back and forth. do it.

[Brief explanation of drawings]

FIG. 1 is an exploded sectional view showing an embodiment of the torque detection device for a continuously variable transmission according to the present invention, FIG. 2 is an expanded sectional view of the entire automatic transmission including the continuously variable transmission mechanism, and FIG. Fig. 4 is an enlarged cross-section of the torque sensor installation part on the primary sheave side, Fig. 5 is a perspective view showing the configuration of the pressure sensor, and Fig. 6 is a circuit showing the gauge connection. 7 is a graph showing the relationship between the load applied to the primary sheave and the input torque, FIG. 8 is a graph showing the relationship between the load applied to the secondary sheave and the output torque, and FIG. 9 is a graph showing the relationship between the load applied to the secondary sheave and the output torque. FIG. 10 is a perspective view of a pressure sensor showing an example. FIG. 10 is an enlarged perspective view of the X section in FIG.

Claims (5)

[Claims] (1) In a torque detection device for a continuously variable transmission in which pressure contact force between transmission elements is generated by a thrust mechanism provided around the axis of a transmission shaft, the operation of the thrust mechanism causes the mechanical part of the continuously variable transmission to A torque detection device for a continuously variable transmission, characterized in that a discontinuously rotating member that receives the generated force is provided with a sensor that detects stress applied to the member. (2) In a torque detection device for a continuously variable transmission in which the pressure contact force between transmission elements is generated by a thrust mechanism provided around the axis of a transmission shaft, a non-continuously rotating member receives an axial thrust generated by the thrust mechanism. A torque detection device for a continuously variable transmission, characterized in that a pressure sensor is provided between the two. (3) The torque detection device according to claim 1, wherein the sensor is a load cell having a strain gauge attached to an annular strain body. (4) The torque detection device according to claim 2, wherein a large number of the strain gauges are arranged along the circumference of the strain body. (5) A primary sheave provided on the input shaft, a secondary sheave provided on the output shaft, a V-belt interposed between the primary sheave and the secondary sheave, and a primary sheave provided on the input shaft and the primary sheave. In a torque detection device for a continuously variable transmission equipped with a V-belt clamping mechanism using a thrust cam interposed between an output shaft and a secondary sheave, a torque detecting device that receives an axial thrust generated by the operation of the V-belt clamping mechanism in opposition. A pressure sensor is interposed between each of the continuously rotating members, and the signal line of the pressure sensor is led out of the case of the continuously variable transmission, thereby making it possible to detect the input shaft torque and the output shaft torque. Torque detection device for gear transmission.