JPH08121585A - Torque sensor for automatic transmission - Google Patents

Abstract

PURPOSE: To eliminate a one-way clutch to lock a carrier by a torque sensor capable of detecting displacement of the carrier in a planetary gear system of an automatic transmission. CONSTITUTION: Spline type teeth 67, 67 are formed on a brake plate 61 of a clutch brake to fix a friction material to be connected to a carrier by way of sandwiching it, and a tooth 68 to insert between them with a clearance left is formed on the side of a case 60. A magnet 91 is installed in the tooth 68 and hole elements 92, 93 are installed on both sides of it. When torque working on the carrier becomes zero in the middle of upshifting from second gear speed to third gear speed, the tooth 68 comes to the middle of the teeth 67, and when it is detected, the clutch brake is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an automatic transmission (A / T) mounted on an automobile, and more particularly, it can detect the direction of torque acting on a clutch brake in a torque phase during a gear shifting operation. The present invention relates to a small torque detection sensor for A / T.

[0002]

2. Description of the Prior Art Automatic transmissions usually incorporate a planetary gear mechanism. Here, the planetary gear mechanism is, as shown in FIG. 7, a sun gear 30 and a ring gear 40, a carrier 20 that can rotate on the same axis as those gears 30 and 40, and a rotatably supported by the carrier 20. The gear train includes a plurality of pinion gears 10 (only one is shown in FIG. 7) that are engaged with the sun gear 30 and the ring gear 40 at the same time. In addition, 50 shows an input shaft and 51 shows an output shaft. In the conventional automatic transmission,
Fix each element of the planetary gear mechanism with friction elements such as clutch brake, band brake, one-way clutch,
Shifting was performed by switching the input, output, and reaction force elements.

[0003]

However, recently, in order to improve the efficiency, weight and size of an automatic transmission, the one-way clutch is abolished, that is, shift control by clutch-to-clutch over the entire shift range. Is being considered. The reason for this is that the one-way clutch is large in size and high in cost, so it is desirable to discontinue it, and as shown in FIG.
As a method of fixing the above, it is necessary to use two friction elements in combination, such that the one-way clutch 21 is actuated during normal driving on the input side, but another clutch brake 22 is actuated during driving on the output side, that is, when the engine brake is actuated. There is one thing.

FIG. 9 shows the operational engagement state of the brake during steady operation of the second and third speeds of A / T. A one-way clutch 31 that stops the unidirectional rotation of the sun gear 30 in the second speed
The brake 32 that backs up the vehicle is freed, and the brake 22 of the carrier 20 is locked. On the other hand, in the third speed, the brake 32 is locked and the brake 22 is free. Therefore, the one-way clutch 21 is abolished, and the shift control using only the clutch brake 22, that is, the clutch toe
In order to perform the clutch shift control (upshift from the 2nd speed to the 3rd speed), it is necessary to make the brake 22 free at an ideal time as in the case where the one-way clutch 21 has conventionally been functioning. As a means for obtaining this free timing signal, as shown by the arrow in FIG. 9, torque in the direction opposite to the rotation direction of the input shaft 50 is applied to the clutch brake 22 in the second speed, while in the third speed. Since torque is applied in the same direction as the rotation direction of the input shaft 50, it is considered to use the zero point at which the direction of this torque switches.

A torque sensor that can be used for this purpose is described in Japanese Utility Model Laid-Open No. 3-125234. In this sensor, a detection coil is attached around an amorphous film bonded to the shaft to be measured, and an output voltage corresponding to a change in magnetostriction is generated in the detection coil. Therefore, when this torque sensor is used for the purpose of detecting the zero point, it is attached to the rotary shaft, so that the place of attachment is restricted.
Further, if a general detection method such as a magnetostriction method or a strain gauge method is used as a sensor for this purpose, there is a problem that the accuracy of zero point detection is lowered due to the influence of heat and oil inside the A / T. .

Therefore, in the present invention, the clutch toe
An object of the present invention is to provide a sensor that does not need to be attached to a rotating shaft in order to accurately detect a conversion point (zero point) in the direction of torque acting on a clutch brake, which is essential for clutch shift control.

[0007]

In order to achieve the above object, the present invention is characterized in that a zero point at which the direction of torque changes is detected from a behavior change of a carrier or a movable part of a clutch brake when torque is applied. And That is, the sensor for detecting the direction of the torque is composed of a Hall element (including an equalizing means) integrated with the magnet, and the Hall element inside the Hall element is changed by the position change of the carrier which is the detection element or the movable part of the clutch brake. It is characterized in that the displacement of the carrier or the movable part of the clutch brake is detected by utilizing the change in the number of passing magnetic fluxes.

[0008]

According to the small torque sensor for A / T of the present invention having the above structure, by measuring the number of magnetic fluxes passing through the Hall element, the change causes the change in the carrier or clutch brake before and after the locked state of the carrier. It is possible to detect a slight change in the position of the movable portion, and as a result, it is possible to determine the change in the direction of the torque applied to the clutch brake.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention corresponding to claim 2 will be described in detail below with reference to the drawings. Also in each of the following embodiments, the same reference numerals are given to the substantially same structural parts as the above-mentioned conventional example, and the duplicated description will be omitted.

The structure of a multi-plate clutch brake used in a general automatic transmission is shown in FIGS. 1 (a) and 1 (b).
The clutch brake 22 includes a carrier 20 that transmits the rotation of the gear, a friction material 23 that receives the rotation of the carrier 20,
A brake plate (movable part) 61 that receives the rotation of the friction material 23, and A / that stops the rotation of the brake plate 61.
It consists of a T case 60. Carrier 20 and friction material 23
1 is movably coupled only in the axial direction by means of tapered spline teeth 24 and 25, respectively, as illustrated in FIG. 1 (b), and the friction material 23 alternately overlaps the brake plate 61. The brake plate 61 and the case 60 are assembled as shown in FIG. 1B in consideration of the function of the detent when locking and the torque capacity of the brake.
The spline structure in which the axial groove 62 of the case 60 and the teeth 64 of the brake plate 61 and the teeth 64 of the end plate 63 engage with each other is exemplified. Furthermore, between the brake plate 61 and the case 60,
There is a slight clearance (difference between the groove width and the tooth width) in consideration of the assemblability, so that the brake plate 61 is slightly movable. Therefore, in this case, the brake plate 61 corresponds to what is called a "movable part". In FIG. 1, 65 is a hydraulic piston for operating the clutch brake 22, and 66 is a snap ring.

The behavior of the carrier 20 when upshifting from the 2nd speed to the 3rd speed is shown in FIG. In the steady state, the carrier 20 is locked by the brake 22 in both the second speed and the third speed.
There should be no relative movement with 3, but in reality,
Since the positive torque is applied in advance at the 2nd speed,
As shown in (a), the teeth 24 of the tapered spline of the carrier 20 bite into the teeth 25 of the tapered spline of the friction material 23 by a taper action in the rotational direction indicated by the arrow to form a positive angle. A minute relative displacement corresponding to the magnitude of the torque is generated between the two. When the positive torque decreases as the gear shifts to the third speed, the friction material 23
The biting amount of the tooth 24 of the carrier 20 with respect to the tooth 25 of the carrier 20 decreases, and when the torque becomes zero, the tooth 24 of the carrier 20 comes to the center between the teeth 25 of the friction material 23 as shown in FIG. Both are in a non-engaged free state. This is the state of the zero point of torque to be detected by the sensor of the present invention. When a further negative torque is applied to shift from that state to the third speed, the carrier 20 slightly dents in the direction of rotation with respect to the friction material 23 on the side opposite to the tip due to the action of the taper, and the carrier 20 shown in FIG. The state shown in FIG. Thereafter, the clearance between the groove 62 and the protrusion 64 is rotated in the torque application direction indicated by the arrow by the amount corresponding to the clearance between the groove 62 and the projection 64, and the steady state of the third speed is achieved.

As described above, in the transition period of the shift, the carrier 20 undergoes three operations of return, bite, and rotation. Therefore, by detecting the point where the bite of the carrier 20 disappears at that time, as shown in FIG. It becomes possible to determine a point (zero point) at which the direction of torque reverses normally and reversely as in the state of b). However, in a normal operating state, there is a period in which the carrier 20 is rotating without being locked,
When it reaches the steady state of the second speed, the friction material 23 is locked by the brake plate 61 and the rotation of the carrier 20 is stopped. Therefore, since the stop position of the carrier 20 also varies, a method of identifying a minute rotation angle due to biting from the rotation angle of the carrier 20 is required, which will be described later in detail.

FIG. 3A shows a basic structure of the present invention corresponding to claim 1. More specifically, what is shown in FIG. 3A is a carrier 20 having a spline shape.
The unevenness of the gear-shaped outer peripheral surface is detected by a magnetic detection element 70 such as a Hall element, and the presence or absence of displacement of the carrier 20 is detected from the difference (ΔV) in output voltage before and after displacement. In this case, if the portion of the carrier 20 stopped before the magnetic detection element 70 has a flat shape, ΔV = 0 may occur as shown in FIG.
Small displacement cannot be detected. (However, if the shape of the spline teeth 24 and 25 is a triangular sawtooth state, detection may be possible in some cases.)

Therefore, FIG. 4 shows a preferred example of the detection device which is not affected by the shape of the carrier 20. Three position detection sensors 7 including Hall element 72 integrated with magnet 71
3a, 73b, 73c are fixedly installed near the side surface of the spline-shaped carrier 20 as shown in FIGS. 4 (a) and 4 (c), and each sensor 7 for detecting unevenness passing therethrough.
The presence or absence of displacement of the carrier 20 is detected from the change (ΔV / Δt) in the output voltage per unit time of 3. As shown in FIG. 3, when the number of the sensors 73 is one, it may not be possible to detect the output change depending on the shape of the carrier 20, so that it is necessary to compensate for the undetectable portion, and the plurality of sensors 73a to 73a. 73c is used. In this case, the plurality of sensors 73a to 73c should not face the flat portion of the carrier 20 at the same time in any case.
The positions of those sensors may be selected. In FIG. 4B, changes in the output voltage of the sensors 73a, 73b, 73c are shown as V ₁ , V ₂ , and V ₃ , respectively. A waveform close to a sine wave is generated because the carrier 20 itself rotates. However, in the steady state of the second speed or the third speed, the carrier 20 is locked and the sine wave disappears. Even when the carrier 20 is locked by the brake 22, when the carrier 20 moves by a minute rotation angle due to the biting into the friction material 23 as described above, the following condition is satisfied for the differential value of the output voltage.

[0015]

[Equation 1]

Therefore, when all the absolute values of the differential values shown in the condition (1) are 0, it may be judged that the torque acting on the carrier 20 is 0, and that state is the conversion point in the direction of the torque described above. That is, at the zero point, (b) of FIG.
Corresponding to the state of.

The above points will be described in more detail with reference to FIGS. 5 and 6. First, the Hall element 72 of any one sensor 73 with respect to the displacement of the carrier 20.
The output characteristics of the are shown in FIG. Since the output voltage is determined by the number of magnetic fluxes passing through the Hall element 72, the carrier 2
The output decreases as 0 moves away from the Hall element 72 of the sensor 73.

FIG. 6A shows three sensors 73a to 73c.
The configuration of a displacement detection system (sensor in a broad sense) using the is shown as a block diagram. This system includes a sensing circuit 80 including a sensor 73, which outputs an analog signal indicating the displacement of the carrier 20, a differentiating circuit 81 for converting the analog signal obtained by the sensing circuit 80 into an output change per unit time, and a differentiating circuit. A displacement determination circuit 82 that includes a window comparator that determines whether the differential value obtained in 81 is greater than or equal to a predetermined threshold value, and an output circuit 83 that ORs the outputs of the displacement determination circuits 82 based on the respective sensors 73. And these actions are shown in FIG. 6 (b).
Is shown in. In this way, the displacement detection system shown in FIG. 6A outputs a signal indicating the displacement of the carrier 20.

Further, in this example, the displacement detecting system is constructed by using three sensors 73, but the number of sensors 73 may be increased or decreased according to the shape of the carrier 20. The sensor (sensing element) 73 is not limited to the hall element 72, and an MRE or the like that operates in the same manner may be used. As long as space allows the detection position, the magnetic detection element 70 shown in FIG. A plurality of position detection sensors 73a to 73c may be arranged near the outside of the outer circumference.

A second embodiment of the present invention corresponding to claim 3 will be described below in detail with reference to the drawings. FIG. 10 shows the case where torque is applied to the clutch brake 22. The specific behavior of the brake plate 61, which is the movable part of the clutch brake 22, is shown. First, in the second speed, the rotational force of the carrier is the brake plate 61 of the clutch brake 22.
When torque is applied to the brake plate 61,
/ Groove 62 of T case 60 and tooth 6 of brake plate 61
It rotates in the direction of torque application indicated by the arrow by the amount of the clearance with 7. Next, if you upshift to 3rd speed,
As shown in FIG. 9, since the rotation directions of the carrier 20 are opposite in the second speed and the third speed, the operation engagement state of the brake 22 changes. Therefore, torque in the opposite direction is applied to the brake 22, and the minimum clearance on the left side of the teeth 67 of the brake plate 61 in FIG.
Maximum at high speed. Therefore, the direction of the torque can be determined by detecting the minute position change of the plate 61.

FIG. 11 shows the structure of a detecting device 90 which is the main part of the second embodiment. The detection device 90 is an A / T case 60.
A magnet 91 provided inside a tooth 68 formed so as to extend between two teeth 67 of the brake plate 61, and two Hall elements 92 integrally arranged on both sides of the magnet 91. It consists of 93. Each hall element 9
FIG. 12 shows the output characteristics of Nos. 2 and 93 with respect to the displacement of the brake plate 61. Since the output is determined by the number of magnetic fluxes passing through the Hall element, two Hall elements 92,
On one side of 93, the output decreases as the teeth 68 of the brake plate 61 move away. On the other hand, in the other Hall element, the output increases as the brake plate approaches. FIG. 13 shows a block diagram of a main part of a signal processing circuit in the displacement detection system. In this example, the output voltages of the two Hall elements 92 and 93 connected to the constant current circuit and having opposite output characteristics are supplied to the differential amplifiers 94 and 95.
After being amplified by, the signal is input to the comparator 96, and the binary signal at the output terminal 97 is inverted at the point where the respective output voltages become equal. According to this configuration, even if the environmental temperature fluctuates, the Hall elements 92 and 93 are equally affected by the temperature, so that there is no inconvenience that the comparison level fluctuates and the judgment level changes.

[0022]

As described above, according to the present invention,
In the automatic transmission, the conversion point (zero point) of the direction of the torque applied to the clutch / brake of the planetary gear mechanism is
Since an extremely small and highly accurate torque sensor for A / T that can be easily detected from the position change of the carrier or the movable part of the clutch brake can be obtained, by using this, the one-way clutch of the automatic transmission can be omitted. It becomes possible to do.

[Brief description of drawings]

FIG. 1A is a vertical cross-sectional view showing the structure of a multi-plate clutch brake, and FIG. 1B is a cross-sectional view seen from the output shaft side.

FIG. 2 is a diagram showing the behavior of a carrier during an upshift from second gear to third gear, divided into three states (a) to (c).

3A and 3B are diagrams showing a configuration and a function of a basic carrier position detection device of the present invention using a magnetic detection element.

4A and 4B are diagrams showing a small torque sensor for A / T as a first embodiment of the present invention, FIG. 4A is a conceptual diagram illustrating the arrangement of the sensor, FIG. 4B is a diagram for explaining the operation, and FIG. FIG. 6 is a vertical cross-sectional view showing a state where the clutch brake is attached.

FIG. 5 is a diagram showing output characteristics of a Hall element with respect to carrier displacement.

6A and 6B show a displacement detection system for the first embodiment, wherein FIG. 6A is a block diagram showing the overall configuration, and FIG. 6B is a diagram showing the operation of each part thereof.

FIG. 7 is a diagram showing a basic configuration of a planetary gear mechanism.

FIG. 8 is a diagram showing a configuration of a general automatic transmission that uses both a one-way clutch and a clutch brake.

FIG. 9 is a diagram showing an engaged state of a brake in a steady state of second speed and third speed.

FIG. 10 is a cross-sectional view showing the behavior of the brake plate at the time of upshifting from 2nd speed to 3rd speed.

FIG. 11 is a sectional view showing a structure of a main part of a displacement detecting device as a second embodiment.

FIG. 12 is a diagram showing output characteristics of two Hall elements with respect to displacement of a brake plate.

FIG. 13 is a block diagram showing a signal processing circuit in a displacement detection system according to a second embodiment.

[Explanation of symbols]

 10 ... Pinion gear 20 ... Carrier 22 ... Clutch brake 23 ... Friction material 24, 25 ... Spline teeth 30 ... Sun gear 40 ... Ring gear 50 ... Input shaft 51 ... Output shaft 60 ... A / T case 61 ... Brake plate (movable part) 70 ... Magnetic detection element 71 ... Magnet 72 ... Hall element 73 ... Position detection sensor 80 ... Sensing circuit 81 ... Differentiation circuit 82 ... Displacement determination circuit 83 ... Output circuit 91 ... Magnet 92, 93 ... Hall element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hidehiro Ohba, 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor, Hiromichi Kimura, 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation ( 72) Inventor Nobuaki Takahashi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd.

Claims (3)

[Claims] 1. A planetary gear mechanism including a sun gear connected to an input shaft, a pinion gear that meshes with the sun gear, a carrier that supports the pinion gear, and a ring gear that is connected to the output shaft and meshes with the pinion gear.
In an automatic transmission including a clutch brake that fixes the carrier to a case, the direction of the torque applied to the clutch brake is set to the direction of the carrier or the clutch brake in order to determine the timing of continuation of the clutch brake during a gear shift. A torque sensor for an automatic transmission, wherein the torque sensor is configured to detect a position change of a part. 2. A plurality of sensing circuits composed of Hall elements integrated with a magnet, a differentiating circuit for converting an analog signal obtained by the sensing circuit into an output change per unit time, and the differentiating circuit. Displacement determination circuit that determines whether the differential value obtained in step 1 is greater than or equal to a predetermined threshold value,
An output circuit for taking the logical sum of the respective sensor outputs is provided, and a minute change before and after the locked state of the carrier is utilized by utilizing the change in the number of magnetic flux passing through the Hall element in response to the change in the position of the carrier. The torque sensor for an automatic transmission according to claim 1, which detects various displacements. 3. A movable clutch element, which comprises a Hall element integrated with a magnet and utilizes a change in the number of magnetic fluxes passing through the Hall element in response to a change in the position of a movable portion of the clutch brake. The torque sensor for an automatic transmission according to claim 1, wherein a minute displacement of the portion is detected.