JPH0452537A - Torque detecting apparatus - Google Patents

Abstract

PURPOSE:To make it easy to form a part to be detected, to improve the assembling accuracy and easiness of a detecting means as well as the detecting accuracy of the axial torque by forming the part to be detected in a pair of members at the to-be- detected side fixed to a power transmission shaft. CONSTITUTION:In this apparatus, a new magnetic pattern can be written in magnetic recording layers 43, 44 at any time when the apparatus starts driving or during driving of the apparatus, and the axial torque of a shaft 3 can be operated accurately without being adversely influenced by the residual torsion of a turbine shaft 3 or the positional displacement of magnetic heads 46, 47. The recording layers 43, 44 are easily formed by flame-spraying magnetic substance to cylindrical members 40, 41 which are made of aluminum alloy and lighter in weight than the shaft 3 for realizing magnetic properties. Moreover, the members 40, 41 rotated integrally with respective fixed parts 3a, 3b are extended to a position corresponding to a cover wall 24, and the recording layers 43, 44 are formed at end parts of the members. Therefore, it is possible to assemble the heads 46, 47 integrally with a holder member 45 with good accuracy, and the assembling easiness is improved. Further, since the members 40, 41 are made long to enlarge the distance between fixed parts 40a and 41a, the detecting accuracy is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a torque detection device that detects shaft torque from a rotational phase difference between two parts of a power transmission shaft spaced apart in the axial direction.

[Prior art]

2. Description of the Related Art Conventionally, as a torque detection device for detecting the shaft torque of a power transmission shaft rotationally driven by an engine, an electric motor, etc., there has been known a torque detection device that detects shaft torque from the torsion angle of the power transmission shaft.

Usually, in the above-mentioned torque detection device, detected parts are formed at two parts separated in the axial direction of the power transmission shaft, and a pair of sensors for detecting these detected parts are mounted on a fixed member outside the power transmission shaft. It is arranged to face the detected part, and is configured to determine the rotational phase difference between two separated parts based on the outputs of both sensors, and calculate the torsion angle of the power transmission shaft from the rotational phase difference to determine the shaft torque. There is.

On the other hand, Japanese Patent Application Laid-Open No. 64-21255 discloses that detection portions having shape magnetic anisotropy are formed in two portions spaced apart in the axial direction of the input shaft of an automatic transmission. A torque detection device is described in which detection coils for detecting each detected portion are fixed to a fixing member on the outer peripheral side of an input shaft, and the shaft torque of the input shaft is detected based on the output from the rain detection coil.

[Problem to be solved by the invention]

In the above-mentioned conventional and published torque detection devices, when forming the detected part on the outer peripheral surface of the power transmission shaft, it is very difficult to precisely form a pair of separated detected parts without phase error. The problem is that it is difficult.

When assembling a pair of sensors, it is necessary to assemble the pair of sensors with high precision because a phase error causes an error in the detected torque. It is extremely difficult to assemble the sensors with high precision to separate parts of the fixed member, and in the case of automatic transmissions, the fixed member only exists in a very limited area on the outer circumference of the power transmission shaft. Therefore, it is not possible to set a large distance apart in the axial direction between the pair of sensors, and there are problems such as that it is difficult to improve the detection accuracy of the shaft torque.

SUMMARY OF THE INVENTION An object of the present invention is to provide a torque detection device in which a detected part can be easily formed, the accuracy and ease of assembly of a detection means such as a sensor can be improved, and the detection accuracy of shaft torque can be improved. It is.

[Means to solve the problem]

The torque detection device according to the present invention is a torque detection device that detects shaft torque from the rotational phase difference between two parts separated in the axial direction of a power transmission shaft. a pair of detected side members each extending to a position corresponding to the fixed member on the outside of the shaft; a detected portion formed on the outer periphery of the other end of each of the detected side members;
The apparatus further includes a pair of detection means that are fixedly attached to the fixed member and detect the pair of detected parts, respectively.

[Effect]

In the torque detection device according to the present invention, one end of the pair of detected members is fixed to two parts of the power transmission shaft, and the other end is located at a position corresponding to the fixed member on the outside of the power transmission shaft. A pair of detection means fixedly attached to the fixed member detects a pair of detection parts formed on the outer periphery of the other end of the detection member, respectively, and detects the two detection parts. The shaft torque of the power transmission shaft is determined from the rotational phase difference between the parts.

As described above, since the pair of detected parts are formed on the pair of detected members, the detected parts can be formed easily and with relatively high precision regardless of the shape and size of the power transmission shaft. Further, if the detection side member is made of a non-magnetic material, the detection part can be easily formed without performing a non-magnetic treatment.

Furthermore, the pair of detection means attached to the fixed member detects the detected part of the detected member extended to the position corresponding to the fixed member, and detects the rotational phase difference between the pair of parts.
There is no need for the detection means to be placed facing a pair of parts separated from each other, and it can be placed facing a pair of detected parts, improving the assembly accuracy and ease of assembly of the detection means. I can do it.

Furthermore, even in cases where the fixed member exists only in a very limited narrow area outside the power transmission shaft, such as in an automatic transmission, 1
By increasing the length of the pair of detected side members, the distance between the pair of separated parts of the power transmission shaft can be set larger, so that the detection accuracy of the shaft torque can be improved.

〔Effect of the invention〕

According to the torque detection device according to the present invention, as described in detail in the [Operation] section above, by forming the detected portions on the pair of detected side members fixed to the power transmission shaft, respectively, the torque detecting device detects the power. To be able to easily form a detected part with high precision regardless of the shape and size of a transmission shaft, to be able to improve assembly accuracy and ease of assembly of a pair of detection means, and to improve shaft torque detection accuracy. Effects such as being able to do this can be obtained.

〔Example〕

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

This embodiment is a case where the present invention is applied to a torque detection device that detects the shaft torque of a turbine shaft of an automatic transmission for an automobile.

First, to briefly explain the automatic transmission 1, as shown in FIG. 1, a turbine shaft 3 is provided coaxially with a crankshaft 2 of an engine (path shown), and a torque converter 4 and an oil pump are connected to the turbine shaft 3. 5 and a multi-stage transmission mechanism 6 are arranged coaxially in order from the engine side, and a hydraulic control valve unit 7 for controlling the speed change of the multi-stage transmission mechanism 6 is provided below the multi-stage transmission mechanism 6.

The torque converter 4 includes a pump 10, a turbine 11, and a stator 12, as shown in FIG. The turbine 11 is connected to the turbine shaft 3 via the turbine hub 16, and the stator 1 is connected to the drive gear 15 of the oil pump 5 through the
2 is connected to the stator fixed shaft portion 22 of the oil pump 5 via a one-way clutch 17, and the rotational force of the crankshaft 2 is transferred from the pump 10 to the turbine 11 via the oil circulating between the pump 10 and the turbine 11. and is transmitted to the turbine shaft 3 via the turbine hub 16.

The oil pump 5 is assembled into a pump housing 20 and a pump cover 21 that are fixed to the casing 8 of the automatic transmission 1, and the pump cover 21 has a substantially cylindrical stator that extends toward the engine and is connected to the one-way clutch 17. A fixed shaft portion 22 and a substantially cylindrical fixed shaft portion 23 extending toward the multi-stage transmission mechanism 6 are formed, and the turbine shaft 3 is connected to the fixed shaft portion 2.
2 and 23 so as to be rotatable.

The hydraulic control valve unit 7 includes a control valve mechanism that switches and controls the multi-stage transmission mechanism 6, etc., and a line pressure setting mechanism that sets the line pressure (hydraulic oil pressure) in the automatic transmission 1. Unit 7 is controlled by control unit 30.

The control unit 1-30 is equipped with a microcomputer storing a control program for executing speed change control with predetermined characteristics, and includes an engine throttle opening sensor 31, an idle switch 32, a vehicle speed sensor 33, and a driver's seat control lever. A plurality of switches 34 detecting the setting state of
Various signals from a torque detection device, which will be described later, etc., are supplied to the control unit 30, and based on these signals, the control unit 30 controls the control valve mechanism and line pressure setting mechanism, depending on the driving state of the vehicle. Automatically changes gears and sets line pressure. The hydraulic control valve unit 7 is a well-known type, and the gear shift and line pressure setting are performed by automatic gear shift control.

The torque detection device is for detecting the shaft torque of the turbine shaft 3 used in line pressure setting control, and is shown in Fig. 2.
As shown in FIG. 3, a pair of front and rear cylindrical members 40 and 41 made of aluminum alloy are loosely fitted in series with a slight gap at a position corresponding to the oil pump 5 of the turbine shaft 3. The fixed parts 40a and 41a at the base end portions 40 and 41 that do not face each other are fixed parts 40a and 41a that are separated from each other in the axial direction of the turbine shaft 3.
The cylindrical members 40 and 41 are fixed to the pair of fixing parts 3a and 3b via pin members 42, and the tips of the cylindrical members 40 and 41 are extended to positions corresponding to the cover wall 24 of the pump cover 21. A slight gap is formed between the parts other than the fixed parts 40a and 41a and the turbine shaft 3, and the cylindrical member 4
0.41 rotates integrally with the turbine shaft 3.

Approximately cylindrical magnetic recording layers 43 and 44 having a predetermined width are formed by thermal spraying on the outer periphery of the opposing tips of the cylindrical members 40 and 41, and a holder member 45 is formed on the inner end of the cover wall 24. A pair of front and rear magnetic heads 46 and 47 facing the magnetic recording layers 43 and 44, respectively, are attached to the holder member 45, and the magnetic heads 46 and 47 are connected to the control unit 30, respectively. The magnetic heads 46 and 47 are capable of writing predetermined magnetic patterns in the magnetic recording layers 43 and 44 using electric signals from the control unit 32, and correspond to the magnetic patterns written in the magnetic recording layers 43 and 44. It is possible to output an electrical signal to the control unit 30.

The above torque detection control will be briefly explained.

A control program for torque detection control is input and stored in advance in the microcomputer of the control unit 30, and for example, when starting operation, the idle switch 3
2 and the neutral switch of switch 34 is O.
When in the N state, that is, during idle operation and when no load is acting on the turbine shaft 3, a digital signal of a predetermined frequency is output from the control unit 30 to the magnetic heads 46 and 47, as shown in FIG. , magnetic patterns corresponding to digital signals having the same frequency and the same phase are written on the magnetic recording layers 43 and 44.

Next, after writing to the magnetic recording layers 43 and 44 is completed, the magnetic patterns stored in the magnetic recording layers 43 and 44 are read by the magnetic heads 46 and 47 at any time, and the positions of the digital signals output from the magnetic heads 46 and 47 are read. The torsion angle of the turbine shaft 3 between the first fixed portion 3a and the second fixed portion 3b is calculated from the phase difference, and the axial torque of the turbine shaft 3 is determined from the torsion angle and output to line pressure setting control.

The calculation of the shaft torque will be explained with reference to FIGS. 4 and 5.

Rotation speed No. of turbine shaft 3 when torque load is released
, the write frequency fO of the magnetic heads 46 and 47 (see FIG. 4), and the number of magnetic dot sequences stored in the magnetic recording layers 43 and 44 as Z, the relationship of equation (1) holds true.

fo""ZNo...(1) Next, when torque is applied to the turbine shaft 3, the turbine shaft 3 is twisted, and as shown in FIG. 5, output is generated from the magnetic heads 46 and 47. A phase difference Δt corresponding to the torsion angle θ of the turbine shaft 3 between the first fixed portion 3a and the second fixed portion 3b is generated in the digital signal. Here, the rotation speed of the turbine shaft 30 is N, the frequency f of the digital signal obtained from the air heads 46 and 47, the torsion angle θ and the phase difference Δ
The relationship of equation (2) holds true for t.

θ=2πNΔt =2π(f/Z)Δt =2π(NO/fD)fΔt...(2) However, (1
), the relationship f=NZ was used.

On the other hand, assuming that the torque loaded on the turbine shaft 3 is T, the relationship between the torque T and the torsion angle θ is as shown in equation (3).

T=πGd' θ/32L...(3) However, G is the transverse elastic modulus of the turbine shaft 3, and d is the first fixed part 3a and the second
The diameter of the turbine shaft 3 between the fixed parts 3b, L is the distance between the first fixed part 3a and the second fixed part 3b.

Next, by substituting equation (2) into equation (3), equation (4) can be obtained. This equation represents the relationship between the torque T and various variables for writing and reading magnetic patterns.

T=π” Gd' (No/fo)fΔt/16
L...(4) Next, the operation of the torque detection device will be explained.

In systems such as automatic transmissions 1 of automobiles, where a wide range of torque is applied intermittently over a long period of time, fatigue accumulates on the turbine shaft 3, resulting in residual torsion even in no-load conditions, or distortion during driving. Due to vibrations, the mounting positions of the magnetic heads 46 and 47 will shift due to aging.

In the above-mentioned torque detection device, a new magnetic pattern can be written in the magnetic recording layers 43 and 44 at the start of operation of the automobile or at any time during operation. The shaft torque of the turbine shaft 3 can be calculated with high accuracy without being influenced.

The magnetic recording layers 43 and 44 are formed by thermally spraying a magnetic material onto aluminum alloy members in order to improve their magnetic properties. Since the magnetic material can be thermally sprayed and the cylindrical members 40 and 41 are much smaller and lighter than the turbine shaft 3, the magnetic recording layers 43 and 44 can be easily formed.

Furthermore, the cylindrical members 40 and 41 that rotate integrally with the fixing parts 3a and 3b are extended to positions corresponding to the cover wall part 24, and magnetic recording layers 43 and 4 are provided at the tips of the cylindrical members 4o and 41, respectively.
4, the magnetic heads 46 and 47 can be assembled to the holder member 45 uniformly, and the magnetic heads 4
As well as being able to improve the assembly accuracy and ease of assembly of 6.47,
Both cylinder members 40 and 41 are lengthened in the axial direction and their fixing portions 4
By setting the dimension between 0a and 41a large, the detection accuracy of the shaft torque of the turbine shaft 3 can be easily improved.

As described above, the axial torque of the turbine shaft 3 can be directly detected with high precision, the formation work of the magnetic recording layers 43 and 44 can be simplified and productivity can be improved, and the magnetic head 46 can be easily detected.
・Effects such as being able to improve the assembly accuracy and ease of assembly of the 47, and being able to improve the detection accuracy of shaft torque can be obtained.

Note that the mounting positions of the magnetic heads 46 and 47 are the cylindrical member 4.
If it is possible to provide only the front side or the rear side of the magnetic recording layers 43 and 44, the magnetic recording layers 43 and 44 may be arranged to face the magnetic heads 46 and 47, respectively, by wrapping the cylinder members 40 and 41 by a predetermined distance. good.

In addition, in this embodiment, the magnetic recording layers 43 and 44 and the magnetic head 4
Although the present invention was applied to a torque detection device equipped with 6 and 47, a plurality of slits and protrusions are formed at positions corresponding to the magnetic recording layers 43 and 44, and the slits and protrusions are detected.
A pair of sensors may be provided to detect the rotational phase difference between the fixed portions 3a and 3b.

In this embodiment, the present invention is applied to the automatic transmission 1 of an automobile, but it can of course be applied to various mechanical devices such as machine tools.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a side view of an automatic transmission, FIG. 2 is a vertical sectional view of main parts of the automatic transmission, and FIG.
FIG. 4 is a longitudinal sectional view of the torque detection device, FIG. 4 is an explanatory diagram of digital signals written in the magnetic recording layer, and FIG. 5 is an explanatory diagram of digital signals read from the magnetic recording layer. 3...Turbine shaft, 3a...First fixing part, 3b...
Second fixing part, 24...Cover wall part, 40, 41...
Cylindrical member, 40a, 41a... fixed part, 43, 44
...Magnetic recording layer, 46,47...Magnetic head.

Claims (1)

[Claims] (1) In a torque detection device that detects shaft torque from the rotational phase difference between two parts separated in the axial direction of the power transmission shaft, one end is fixed to each of the above parts, and the other end is a fixed member on the outside of the power transmission shaft. a pair of detected side members each extending to a position corresponding to the detected side members; a detected portion formed on the outer periphery of the other end of each of the detected side members; 1. A torque detection device comprising: a pair of detection means for respectively detecting a pair of detected portions.