JPH0718767B2 - Torque detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a detector that detects torque applied to a shaft.

<< Prior Art >> Japanese Patent Application Laid-Open No. 60-213569 is known for this type of detector, and an example thereof is shown in FIG.

In the figure, gears 32 and 33 are fixed to a shaft 31 that transmits torque at a somewhat long interval, and a sensor casing 34 is mounted between them.

Permanent magnets 35 and 36 are provided on the left and right inside the casing 34, and sensor coils 37 and 38 are fixed to the permanent magnets 35 and 36.

Further, gears 39 and 40 having teeth facing the gears 32 and 33 are provided in the casing 34, and the case 34 is provided with a bearing 4
It is attached to the shaft 31 via 1,42.

Therefore, torque is transmitted and the shaft 31 between the gears 32 and 33 is transmitted.
When the part is twisted and deformed, a phase difference is generated between the detection signals of the sensor coils 37 and 38, and the torque transmitted through the shaft 31 is measured from the phase difference.

<< Problems to be Solved by the Invention >> However, in the above-mentioned conventional example, the gears 32 and 33 are arranged at distant positions on the shaft 31, and the permanent magnets 35 and 33 are arranged in the radial direction of the shaft 31.
Since the sensor 36, the sensor coils 37, 38, the gears 39, 40, and the bearings 41, 42 are arranged, it is necessary to secure a large space around the sensor for mounting the sensor on the shaft 31.

For this reason, it has been difficult to attach a sensor to the output shaft of the vehicle to detect the torque output from the transmission of the vehicle.

The present invention has been made in view of the above conventional problems,
It is an object of the present invention to provide a torque detector which can be easily mounted without being limited in space.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention provides: a hollow shaft that is rotationally driven so that an input torque input to one end is output as an output torque from the other end; A twist amount detecting shaft inserted into the hollow portion of the hollow shaft, one end of which is fixed to the other end of the hollow shaft and the other end of which protrudes from one end of the hollow shaft, and which is arranged on the other end side of the twist amount detecting shaft. And an optical sensor for optically detecting a rotational phase difference between one end of the hollow shaft and the other end of the twist amount detecting shaft.

<< Operation >> In the present invention, when a torque is input to one end of the hollow shaft, the hollow shaft is rotationally driven by the torque output from the other end. Further, the twist amount detecting shaft is inserted into the hollow portion of the hollow shaft, one end is fixed to the other end of the hollow shaft, and the other end projects from one end of the hollow shaft. When the hollow shaft is twisted by the torque, a rotational phase difference occurs between one end of the hollow shaft and the other end of the torsion amount detection shaft, and this rotational phase difference is arranged on the other end side of the torsion amount detection shaft. Optically detected by an optical sensor.

<< Description of Embodiments >> Preferred embodiments of a torque detector according to the present invention will be described below with reference to the drawings.

The torque output from the vehicle transmission is detected by the torque detector shown in FIG. 1, and the reduction gear shaft 2 is rotatably supported in the transmission casing 1 in FIG.

The transmission output torque is input to the gear 3 fixed to the left end side of the reduction gear shaft 2, and the input torque is the gear 4 provided on the right end side of the reduction gear shaft 2.
Is output to the differential gear 6 via the final drive gear 5.

Further, the reduction gear shaft 2 is hollow, and a displacement shaft 7 (twisting amount detection shaft) is inserted into the reduction gear shaft 2.

Also, the rear end of the displacement shaft 7 inserted is the reduction gear shaft 2
It is fixed by a key 8 and a snap ring 9 on the right end side of, and the left end of the displacement shaft 7 projects from the left end of the reduction gear shaft 2.

Here, when the output torque of the transmission is applied to the reduction gear shaft 2 via the gear 3, the reduction gear shaft 2 is twisted and deformed, and the rotation of the left end side and the right end side of the reduction gear shaft 2 depends on the input torque. Occurs (up to 5 degrees).

Therefore, the left end of the reduction gear shaft 2 and the displacement shaft 8
There is a phase difference in the rotation of the left end of.

A gear 10 is engraved on the left end outer peripheral surface of the reduction gear shaft 2 among the reduction gear shaft 2 and the displacement shaft 7, and a gear 11 is fixed to the left end of the displacement shaft 7 by a snap ring 12.

The left ends of the reduction gear shaft 2 and the displacement shaft 7 project from the casing 1, and the projecting portions are covered with the sensor case 14 of the optical sensor 13.

Further, the optical fibers 15A and 16A for transmitting light and the optical fibers 15B and 16B for receiving light are provided toward the tooth flanks of the gears 10 and 11 from above.
Is inserted through the ceiling surface of the sensor case 14, and the insertion tips of the optical fibers 15A, 16B, 15A, 16B face the ridges of the gears 10, 11 with a minute gap as shown in FIG.

The tooth crests of these gears 10 and 11 are finished as light reflecting surfaces, while the roots are finished as light absorbing surfaces.

The optical fibers 15A and 16A have LEDs 17 and 18 as shown in FIG.
Of the output lights are given to the gears 10 and 11 via the optical fibers 15A and 16B, respectively.

The reflected lights of the gears 10 and 11 are given to the phototransistors 19 and 20 of FIG. 3 through the optical fibers 15B and 16B, respectively, and as a result, the phototransistors 19 and 20 respectively obtain rectangular wave-shaped light receiving signals.

A phase difference corresponding to the rotational phase difference between the gears 10 and 11 is generated between these received light signals, and the rotational phase difference is caused by the torsional deformation of the reduction gear shaft 2. Corresponds to the torque input to the reduction gear shaft 2 from the transmission.

The received light signals of the phototransistors 19 and 20 are respectively waveform-shaped by the two operational amplifiers 21a and 21b provided in the comparator 21, and both operational amplifiers 21a and 21b have the waveform-shaped signals A and B shown in FIG. Are obtained respectively.

The waveform shaping signals A and B of both operational amplifiers 21a and 21b are respectively supplied to a positive / negative determination circuit 22 for determining the direction of the torque applied to the reduction gear shaft 2 and an absolute torque detection circuit 23 for detecting the absolute value thereof. It

In the positive / negative determination circuit 22, both waveform shaping signals A and B are converted into differential signals C and D in FIG. 4 by the CR differentiating circuit, and then the differential signal C, D is obtained by using the two gate elements 22a and 22b. Only the differential pulse at the position where the waveform shaping signals A and B rise from D is E = C
・ B, F = D, A are extracted according to the equation, and their gate signals E, F (see FIG. 4) are supplied to the set inputs of a pair of flip-flops 22c, 22d whose Q signal is applied to the other reset input. To be done.

As a result, one flip-flop 22c always obtains an H-level Q signal P when the vehicle forward torque is applied to the reduction gear shaft 2, and the other flip-flop 22d applies the vehicle backward torque. In this case, the Q signal N that is always at the H level is obtained.

Therefore, when the direction of the torque input to the reduction gear shaft 2 is reversed, the direction of the input torque is positive or negative when the one of the waveform shaping signals A and B rises first.
It is immediately judged at 22.

On the other hand, in the absolute torque detection circuit 23, both waveform shaping signals
Gate signal of FIG. 5 with two gate elements 23a and 23b from A and B
G and H are respectively obtained according to the equations of G = A · B and H = A · B, and the gate signals G and H become exclusive OR with respect to the signals A and B by using another gate element 23c. Gate signal I It is obtained according to the formula.

Further, the gate signal I is applied to gate elements 24a and 24b (AND elements) provided in the analog output circuit 24,
The Q signals P and N are applied to the gate elements 24a and 24b, respectively.

The gate signals of these gate elements 24a, 24b are given to the non-inverting input and the inverting input of the operational amplifier 24c, and as a result, in the analog output circuit 24, the direction of the torque input to the reduction gear shaft 2 is indicated by polarity, A temporary delay signal J shown in FIG. 5 whose value is represented by a level is obtained.

In this embodiment, the Q signals P, N of the positive / negative determination circuit 22 and the gate signal I of the absolute torque detection circuit 2 are given as a signal indicating the direction and absolute value of the transmission output torque by a microcomputer (not shown). In the microcomputer, these signals P, N, I are used for its control.

Further, in the temporary delay signal J of the analog output circuit 24, the value of the transmission output torque is indicated by the level thereof, and the direction of the torque is indicated by the polarity thereof.
Is output to the analog display as it is.

As described above, according to this embodiment, the displacement shaft 7 is inserted into the hollow reduction gear 2, and one end of the displacement shaft 7 is fixed to the load side end of the reduction gear shaft 2.
Since the rotational phase difference between the other end of the reduction gear shaft 2 and the other end of the displacement shaft 7 protruding from the other end is detected,
The members required for torque detection can be centrally arranged on the left end side of the reduction gear shaft 2, so that the detector can be easily attached without requiring a large space, and the degree of freedom of attachment can be significantly increased.

Further, since the optical sensor 13 is used for torque detection, the sensor case 14 attached to the casing 1 can be made extremely small, and therefore the attachment can be facilitated.

The optical sensor 13 exposed to a high temperature can be composed of a member that causes almost no structural or physical deformation or alteration with respect to temperature, and the circuit of FIG. 3 affected by temperature has optical fibers 15A, 15B, 16A. , 16B can be placed at a distant place, so that the output torque of the transmission can always be accurately measured regardless of temperature, and the durability and reliability of the detector can be improved.

Furthermore, since the rotational phase difference between the reduction gear shaft 2 and the displacement shaft 7 is detected by the circuit of FIG. 3 via the optical fibers 15A, 15B, 16A, 16B, the influence of external noise can be effectively eliminated. Becomes

In addition, in this embodiment, as shown in FIG.
26 prevents oil from entering the sensor case 13.

A second preferred embodiment of the detector according to the present invention is shown in FIG. 6, and the same members as those in FIG. 1 are designated by the same reference numerals and their description will be omitted.

In this embodiment, the optical fiber 15 inserted in the sensor case 14
Both end surfaces of A and 15B are opposed to each other with a minute gap therebetween, and both end surfaces of optical fibers 16A and 16B are also opposed to each other with a minute gap therebetween.

A disk-shaped detection plate 27 shown in FIG. 7 is attached to the left end of the reduction gear shaft 2, and a similar detection plate 28 is attached to the left end of the displacement shaft 7 in a vertical posture. A snap ring 29 is used to attach the detection board 27.

The detection boards 27 and 28 are arranged between the opposed end surfaces of the optical fibers 15A and 15B and between the opposed end surfaces of the optical fibers 16A and 16B, respectively. As can be understood from FIG. A large number of slits 30 are formed in an array around the rotation shafts.

Therefore, in the present embodiment, the light given from the optical fibers 15A, 15B to the optical fibers 16B, 16B is interrupted by the rotation of the reduction gear shaft 2 and the displacement shaft 7 by the detection plates 26, 27, respectively, and is input to the reduction gear shaft 2. A phase difference corresponding to the generated transmission output torque is generated in the optical intermittent operation.

The intermittent light guided by the optical fibers 15B and 16B is given to the phototransistors 18 and 19 of FIG. 3 in the same manner as in the above-mentioned embodiment, and the same signal processing is performed.

<< Effects >> As described above, according to the present invention, the optical sensor is arranged at a position that optically detects the rotational phase difference between the one end of the hollow shaft and the other end of the twist amount detection shaft. Since the sensor can be centrally arranged on the other end of the twist amount detecting shaft, the optical sensor can be easily attached without requiring a large space, and the degree of freedom in the attachment can be significantly increased.

Further, since the torque detection is performed optically, the sensor can be downsized, which further facilitates the mounting of the sensor.

Then, torque detection is performed at the other end of the hollow shaft that is retracted from the hollow shaft that is exposed to high temperatures, and a torque that does not structurally or physically deform or deteriorate with temperature can be used for the torque detection. Nevertheless, torque detection can always be performed with high accuracy, and the reliability and durability of the sensor can be improved.

Furthermore, since the circuit element can be arranged at a position away from the hollow shaft by using the optical fiber as in the above-mentioned both embodiments, the torque can be always detected with high reliability without adversely affecting the detection circuit due to electrical noise. Becomes

[Brief description of drawings]

FIG. 1 is a sectional view showing a first preferred embodiment of the device according to the present invention, FIG. 2 is a sectional view of the essential parts of the first embodiment, and FIG.
Signal processing circuit diagrams used in the embodiment, FIGS. 4 and 5
FIG. 6 is a characteristic diagram showing signal waveforms in respective parts of FIG.
FIG. 7 is a sectional view showing a second preferred embodiment of the device according to the present invention, FIG. 7 is a configuration explanatory view of a detection plate used in the second embodiment, and FIG. 8 is a configuration explanatory view of a conventional sensor. is there. 2 ... Reduction gear shaft, 3, 4 ... Gear, 7 ... Displacement shaft, 8 ... Key, 9 ... Snap ring, 10,
11 …… Gear, 15A, 15B, 16A, 16B …… Optical fiber, 17,18…
… LED, 19,20 …… Phototransistor, 21 …… Comparator, 22 …… Positive / negative judgment circuit, 23 …… Absolute torque detection circuit, 24 …… Analog output circuit, 27,28 …… Detection board.

Claims (1)

[Claims] 1. A hollow shaft rotatably driven so that an input torque input to one end is output as an output torque from the other end; and a hollow shaft inserted into the hollow portion of the hollow shaft, wherein one end is the other end of the hollow shaft. A twist amount detecting shaft fixed to the other end of the hollow shaft and protruding from one end of the hollow shaft; and the one end of the hollow shaft and the other end of the twist amount detecting shaft disposed on the other end side of the twist amount detecting shaft. An optical sensor that optically detects the rotational phase difference of the torque detector.