JPS63312552A - Torque detector for automatic transmission - Google Patents

Abstract

PURPOSE:To detect shift shock and the like correctly by forming a torque detection face of shape-magnetic-anisotropy on the outer peripheral face of output side rotary member of a fastening element, mounting a torque detector on the opposing transmission side member. CONSTITUTION:On the outer peripheral faces of a clutch drum 10a and a rotary drum 21, a torque detection face 31 which generates magnetic anisotropy due to shapes of first and second groups inclining 45 deg. in different directions to each other. And on a transmission case 1 opposing thereto, a torque detector 32 of torque detecting device 30A-30C having detection coils are mounted. The transmission rate in the torque detection face 31 changes according to pulling force or compression caused by the torque which acts on the torque detection face 31, and the rate is detected by torque detector 32 and sent to a measuring part 33. In this manner it is possible to correctly detect fluctuation in torque due to shift shock without contacting and to enable a good shift control.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a torque detection device that detects rotational torque transmitted to the output shaft of an automatic transmission used in a vehicle, and in particular, relates to a torque detection device that detects rotational torque transmitted to the output shaft of an automatic transmission used in a vehicle, and in particular, the present invention relates to a torque detection device that detects rotational torque transmitted to the output shaft of an automatic transmission used in a vehicle. It is designed to detect

[Conventional technology]

Conventional torque detection devices for automatic transmissions include, for example, Japanese Patent Laid-Open No. 61-127952 and Japanese Patent Laid-Open No. 61-127.
There is one described in the No. 953 publication.

In this conventional example, one or more torque detectors each having a built-in torque detection element are attached to the rear end of a transmission case of a vehicle, a fitting structure, a rib and a screw structure that engages with the rib, and a screw structure that engages with the fitting structure.
Alternatively, the torque detector is attached using a flange structure, and the detection surface of the torque detector is opposed to the output shaft extending from the transmission case at a predetermined distance in the circumferential direction.

The torque detector has a configuration in which an excitation coil and a detection coil are wrapped around a substantially U-shaped magnetic core, and the outer peripheral surface of the output shaft facing the torque detector is designed to increase detection sensitivity. A thin film (ribbon) made of a magnetically permeable material such as amorphous and having a thickness of 20 to 30 μm is adhered to the substrate with a heat-resistant adhesive.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional torque detection device for an automatic transmission, a torque detection head in which an excitation coil and a detection coil are wound around a magnetic core is used as a torque detector, so the installation position thereof is limited to the transmission. When detecting torque fluctuations caused by shift shock that occurs when a fastening element is activated, it is limited to the rear extension connected to the outside and cannot be installed inside the transmission case. Since various coupling members are interposed between the two, there is a large response delay, and when a torque fluctuation due to a shift shock is detected at the output shaft, there is a problem that control to suppress the shift shock cannot be performed satisfactorily. Ta.

Therefore, the present invention has been made by focusing on the problems of the above-mentioned conventional example, and by detecting the torque of the automatic transmission on the output side of the fastening element in the transmission case, the above-mentioned problems of the conventional example are solved. It is an object of the present invention to provide a torque detection device for an automatic transmission that can solve the problem.

[Means for solving problems]

In order to achieve the above object, the present invention provides an automatic transmission system in which driving force from an engine is transmitted through an input shaft, and the driving force is automatically shifted and transmitted to an output shaft by appropriately selecting a plurality of fastening elements. In the transmission, a torque detection surface having shape magnetic anisotropy is formed on the outer peripheral surface of the output side rotating member of the fastening element, and a torque detector having a detection coil is provided on the transmission case side member facing the torque detection surface. It is characterized by being worn.

[Effect]

In this invention, by directly imparting shape magnetic anisotropy to the outer circumferential surface of the output side rotating member of a fastening element such as various clutches in an automatic transmission, or by pasting a thin film having shape magnetic anisotropy. By forming a torque detection surface and arranging a torque detector including a flat detection coil opposite to the torque detection surface, the magnetic permeability of the torque detection surface is reduced by the tensile or compressive force caused by the torque acting on the torque detection surface. As this permeability changes, the change in magnetic permeability is detected by a detection coil. In this way, since it is only necessary to provide a detection coil as a torque detector, the torque detector is placed in a small gap between the output rotating body of the fastening element and the opposing transmission side in the transmission case. Therefore, it is possible to accurately detect the torque fluctuation of the fastening element that causes a shift shock without response delay.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view of an automatic transmission showing one embodiment of the present invention.

In the figure, l is a transmission case, and a torque converter housing 2 is integrally connected to the front end of the transmission case, and a rear extension 3 is integrally connected to the rear end of the transmission case.

An oil pump housing 4 and an oil pump cover 5 are disposed between the transmission case l and the torque converter housing 2, and an input shaft 6 is inserted into the transmission case 1 through the cylindrical portion of the oil pump cover 5. There is.

A turbine 7t of a torque converter 7 is spline-coupled to a position of the input shaft 6 inside the torque converter housing 2, and a sun gear 8a of a hydraulic net gear 8 is fixed to a rear end inside the transmission case 1.

As schematically shown in FIG. 4, a planet carrier 8C of the rear planetary gear 8 is connected to an internal gear 9d of the front planetary gear 9.

On the other hand, a high clutch 10 is inserted between the input shaft 6 and the planet carrier 9C of the front planetary gear 9, and a reverse clutch 11 is inserted between the input shaft and the sun gear 9a of the front planetary gear 9. A band brake 12 is connected to the ten clutch drums lOa.

Also, internal gear 8d of rear planetary gear 8
and front planetary gear 9 planet carrier 9
A forward one-way clutch 13, a forward clutch 14, and an overrun clutch 15 are inserted in parallel between the forward planetary gear 9 and the fixed part, and a low-and-reverse brake 16 and a row one-way clutch are inserted between the planet carrier 9C of the forward planetary gear 9 and the fixed part. A clutch 17 is connected in parallel.

On the other hand, planet carrier 8 of rear planetary gear 8
An output shaft 18 disposed coaxially with the input shaft 6 is spline-connected to C, and the output shaft 18 is connected to a propeller shaft (not shown) through the rear extension 3.

The output shaft 18 is rotatably supported by a newdle bearing 19 inserted between the end plate portion 1a of the transmission case 1, and the output shaft 17 is mounted on the end plate portion 1a within the transmission case 2. A cylindrical member 20 is fixedly extending and facing the cylindrical member 20 .

The clutch drum lOa of the high clutch 10, the forward clutch 14, the overrun clutch 15, and the low and reverse brake 1 constituting the engagement elements
Forward clutch 14 of rotating drum 21 connecting 6
Torque detection devices 3OA, 30B, and 30C are provided between the transmission case 1 and a position corresponding to the overrun clutch 15 to detect rotational torque transmitted by each engagement element.

As shown in FIGS. 2 and 3, each of the torque detection devices 30A, 30B, and 30C has a torque detection surface 31 formed on the outer peripheral surface of each drum 10a and 21, and a torque detection surface 31 that faces the torque detection surface 31. It is composed of a torque detector 32 made up of a coil, and a measuring section 33 that measures rotational torque based on a detection signal from the torque detector 32.

The torque detection surface 31 is formed on the outer peripheral surface of each of the drums 10a and 21, and includes a plurality of groups a, . . . along the outer peripheral surface.
. . , a first group column 34A (see Fig. 3.6), and a plurality of groups b.

. . , the second group column 34B (3rd degree 6th
(see figure).

In addition, each of the groups a, . . . , a has a drum 10
An inclination angle of +45 degrees with respect to the axial direction of a and 21 (see arrow A in Figure 2) (Here, the axial direction is the reference axis, and counterclockwise from this point is positive, and clockwise is taken. On the other hand, group b,...
, b are formed at regular intervals with an inclination angle of −45 degrees and a predetermined depth (for example, 1 mm).

By the way, groups a, ..., a and su, ..., b
By providing 1. second group column 34A,
34B includes groups a,..., between a and...
Line-shaped protrusions a' as part of the circumferential surfaces of the drums 10a and 21 between ..., b, ... a / and b',
..., b' is formed (see Fig. 6).

These protrusions a',..., a' and b',...1.
I guides the magnetic flux φ for torque detection, which will be described later, at a predetermined angle of inclination (45 degrees in this embodiment) with respect to the shaft axis direction (see the dotted line in FIG. 6). and 21 1st. Second group column 34
A and 34B can have mutually different shape magnetic anisotropy.

For this reason, groups a,..., a and s,..., b
The group length, group width, and group interval for each are set to predetermined values that can ensure the above-mentioned shape magnetic anisotropy.

In practice, the group row 34A of the torque sensing surface 31.

34B are integrally formed when the clutch drum 10a or the rotary drum 21 is press-molded.

Here, the first example in this embodiment. Second group column 34
A and 34B are set to have so-called positive magnetostrictive characteristics, in which the magnetic permeability increases when subjected to tensile deformation.

On the other hand, the torque detector 32 is connected to each group column 34A, 34
A first . It is composed of second coils 35A, 35B, and first and second yokes 36A, 36B that are fixedly arranged on the inner circumferential surface of the cylindrical member 20 and hold these coils 35A, 35B wound therein. .

On the other hand, the aforementioned measuring section 33 is configured as shown in FIG. To explain this in detail, in the figure, 40 is the first . Second coils 35A, 35B and resistance (resistance value R+
, Rz) is a bridge circuit with 41A and 41B. In this bridge circuit 40, the inductance of the first coil 35A.

is a value that includes the inductive inductance of the first group column 34A, and similarly, the inductance L2 of the second coil 35B is a value that includes the inductive inductance of the second group column 34B. An AC power source 42 is connected to input terminals a and b of this bridge circuit 40, while 1. The output ends c and d are connected to a signal processing section 43 that processes the detection signal.

Here, the frequency of the AC power supply 42 is the group column 34A,
The magnetic flux passing through the 34B is distributed only on its surface, which is a sufficient value (for example, 10kHz) to cause the so-called skin effect.
~30kHz).

Further, the signal processing section 43 operates at the output terminal c of the prefuji circuit 40.
, a rectifier circuit 44 that converts the detection signals from d to direct current, respectively.
A, 44B, and a differential amplifier 45 that takes the output of the rectifier circuit 44A as a positive signal and the output of the rectifier circuit 44B as a negative signal, amplifies the difference between them, and outputs the amplified signal as a torque detection signal. has been done.

Here, in this embodiment, the inductances L+, L! of the bridge circuit 40 are is set so that L1=Lt in a state where no rotational torque is transmitted to each drum 10a and 21. Therefore, in this state, the resistor 41A is set so that the output of the bridge circuit 40 is zero, that is, in an equilibrium state.
The resistance values R1 and Rt of 41B and 41B are set.

Next, the operation of the above embodiment will be explained.

First, when the select lever (not shown) is set to the neutral range or the parking range, at least the forward clutch 14 and the reverse clutch 11 are controlled to be in an open state, and the rotational force from the engine input to the input shaft 6 is controlled to be in the open state. is not transmitted to the output shaft 18, and the output rotational torque remains zero. In this case, the AC power supply 42 of the measurement unit 40 is turned on, and the first and second coils 35A
When an alternating current of a predetermined frequency is supplied to 35B and 35B, the seventh
A magnetic closed circuit as shown by dotted lines in the figure is formed. That is, if we look at this with respect to the magnetic circuit connected to the first coil 35A, each magnetic flux φ passes through the first yoke 34A, the air gap, the first group row 34A, and then returns to the air gap and the first yoke 36.
The same goes for the magnetic circuit connected to the second coil 35B.

At this time, the first. The magnetic flux φ, .
The surface portions of the second group rows 34A, 34B, that is,
Groups a,..., line-shaped protrusions a',..., a' and b',...
・,b' and pass at positive or negative inclination angles of 45 degrees with respect to the axial direction (see dotted lines in FIG. 6), and in this state, as described above, the inductance L l= Since Lt, the AC outputs of the output terminals c and d of the bridge circuit 40 are in the same phase and have the same potential. Therefore, the DC outputs of the rectifier circuits 44A and 44B are equal, the output value of the differential amplifier 45 is zero, and the output shaft 1
8 shows the rotational torque applied.

In this state, when the drive range or 2 range is selected with the select lever in order to start the vehicle, the forward clutch 14 and overrun clutch 15 are engaged accordingly, and the forward one-way clutch 13 and row one-way clutch 17 are engaged. The rotational force from the engine that is transmitted to the input shaft 6 is transmitted to the output shaft 18 via the sun gear 8a + pinion gear 8b of the rear planetary gear 8, and the planet carrier 8C, and the output shaft 18 is Start rotating.

At this time, as the forward clutch 14 is engaged, the action of the row one-way clutch 17 and the forward one-way clutch 13 prevents the internal gear 8d of the rear planetary gear 8 from rotating in the reverse direction. The reaction torque in the reverse direction generated at 8d is transmitted to the rotating drum 21 via the forward one-way clutch 13 and the forward clutch 14, and this reaction torque is detected by the torque detection device 30B.

That is, when a reaction torque in the reverse direction is transmitted to the rotating drum 21, the first group row 34A undergoes tensile deformation in the direction shown by ■-■ in FIG. The group row 34B undergoes compression deformation in the direction indicated by ■-■ in the figure. This causes the first group column 34
In A, the inductance L1 increases because the magnetic permeability increases, whereas in the second group column 34B, the magnetic permeability decreases, so the inductance L1 increases! decreases.

Therefore, in the bridge circuit 40 of the measuring section 33, the voltage of the output on the output terminal db side is higher than the output on the output terminal cb side. Therefore, in the signal processing section 43, the output of the rectifier circuit 44B becomes larger than the output of the rectifier circuit 44A, and the differential amplifier 45 outputs a torque detection signal having a negative value.

When the vehicle is accelerated from this starting state, the band brake 12 operates and fixes the sun gear 9a of the front planetary gear 9, so that the rotational force transmitted to the input shaft 6 is transferred to the sun gear 8a of the rear planetary gear 8, Output shaft 18 via pinion gear 8b and planet carrier 8C
The data is transmitted from the planet carrier 8C to the internal gear 9d of the front planetary gear 9, the pinion gear 9b, the planet carrier 9C forward clutch 14, the forward one-way clutch 15, the internal gear 8d of the rear planetary gear 8, and the pinion gear 8b. The rotational power transmission system leading to
The speed is increased by the amount that the motor rotates, and the automatic transmission is shifted to second gear. At this time, the actuation of the band brake 12 causes a torque fluctuation in the clutch drum 10a due to the reaction torque in the reverse direction, and this torque fluctuation is detected by the torque detection device 31A, and the forward clutch 14 is Rotational torque in the rotation direction is transmitted, and this transmitted torque is detected by the torque detection device 30B. That is, the first group row 34A of the torque detection device 30B is compressively deformed in the direction shown by ■-■ in FIG. 6, while the second group row 34B is compressed in the direction shown by ■-■ in the same figure. undergoes tensile deformation. Due to this deformation,
In the first group row 34A, the magnetic permeability decreases, and the magnetic flux φ, . On the other hand, in the second group row 34B, the magnetic permeability increases and the magnetic flux φ passing therethrough increases.
,..., φ increases and eventually becomes inductance! increases.

Therefore, in the bridge circuit 40 of the measuring section 33, the balance is lost, and the voltage of the output on the output terminal c-b side becomes higher than the output on the output terminal d-b side.

Therefore, in the signal processing section 43, the rectifier circuit 44
The output of A becomes larger than the output of rectifier circuit 44B,
A rotational torque detection signal indicating a positive value is output from the differential amplifier 45.

Furthermore, when the vehicle is accelerated, the band brake 12
becomes inactive, and instead of this, the high clutch 10 is engaged, and the rotational force in the normal rotation direction transmitted to the input shaft 6 is transmitted to the sun gear 8a and internal gear 8d of the rear planetary gear 8, and these are By rotating forward at the same speed, the state becomes more accelerated and becomes the third speed state, and at this time, the torque fluctuation due to the shift shift due to the engagement of the high clutch 10 is transmitted to the rotating drum 21 via the planetary carrier 9C of the front planetary gear 9. Since it is transmitted to
It can be detected by the torque detection device ff30B.

On the other hand, when the select lever is in the neutral range or parking range and selects the reverse range, the reverse clutch 11 is engaged, the low and reverse brake 15 is activated, and the rotational force transmitted to the input shaft is transferred to the reverse clutch 11. ．． front planetary
The signal is transmitted to the output shaft 18 via the sun gear 9a of the gear 9, the pinion gear 9b, the internal gear 9d, and the planet carrier 8C of the rear planetary gear 8.
8 will rotate in the opposite direction. At this time, rotational torque in the same direction as the input shaft 6, that is, in the normal rotation direction, is transmitted to the clutch drum 10a of the high clutch IO, and this is detected by the torque detection device 30A.

On the other hand, by operating the low and reverse brake 15 on the rotating drum 21, the planet carrier 9C of the front planetary gear 9 is fixed, and a reaction torque in the forward rotation direction is applied to the planet carrier 9c. The reaction torque is detected by the torque detection device 30B.

Therefore, when the above-mentioned measurement is performed for various rotational torques for each rotational direction of each drum 10a and 21, the value of the rotational torque applied to the rotational drums 10a and 21 and the first
．． Second group column 34A.

Since there is a proportional relationship with the magnetic permeability value of 34B, the 8th
The results shown in the figure are obtained. That is, when the rotational torque is zero, the output voltage of the signal processing section 43 is zero, and when rotational torque is applied in the clockwise or counterclockwise direction from this state, a positive or negative voltage proportional to the torque value is applied. Output voltage is obtained. In other words, the magnitude of the rotational torque input to the drums 10a and 21 can be determined by the value of the output voltage, and the direction in which the rotational torque is applied can be determined by the positive or negative value of the output voltage. By performing feedback control of engagement elements such as clutches in the system, shift shock can be prevented and optimal shift control can be performed. In particular, since torque fluctuations caused by shift shocks in fastening elements can be detected near the fastening elements that cause the shift shocks, torque fluctuations can be detected accurately and response delays in feedback control can be reduced. .

This embodiment has various advantages because it is configured and operates as described above.

First, the torque detection surface 31 is directly attached to the outer peripheral surfaces of the clutch drum 10a and the rotating drum 21 in groups a, . . . , a.
and..., b, thereby forming the drum 10
Since it is composed of a single member that utilizes the magnetic properties of a and 21 itself, the processing process is simpler and cheaper than when pasting a magnetostrictive thin film, and it is also mechanically robust. Furthermore, unlike in the case of a composite member to which a magnetostrictive thin film is attached, there is no difference in thermal expansion coefficient between members, and the temperature characteristics are improved. Since each is formed over the circumferential surface, the detection output is averaged in the circumferential direction, and the drum 10
It is not directly affected by local disturbances in magnetic properties such as joints between drums 10a and 21 or internal structural defects, and even if eccentricity occurs in drums 10a and 21, the influence of this eccentricity error is absorbed The torque detection accuracy can be significantly improved because the two sides can cancel each other out.

Furthermore, in this embodiment, the torque detection surface 31 is configured such that the two group rows 34A and 34B receive deformation forces in mutually opposite directions with respect to rotational torque, so that output signals of opposite polarity can be obtained. As a result, the range width of the detection signal for changes in torque can be set wide, and both clockwise and counterclockwise rotations can be detected while maintaining the above-mentioned high accuracy.

Furthermore, in this embodiment, the first. Second coil 35A
, 35B are used for both excitation and detection, it is possible to make the device more compact compared to a case where both coils are wound separately.

In the above-described embodiment, the first torque detection surface is used as the first torque detection surface. Although the case where the second group columns 34A and 34B are provided has been described, the present invention is not necessarily limited to this, and for example, only one of the above-mentioned rows is provided.
The configuration can also be simplified, and in that case, depending on how the pre-fuji circuit 40 of the measuring section 33 is assembled, it becomes possible to appropriately measure one or both rotational torques. On the other hand, in the above case, if there is sufficient mounting space, multiple sets of torque detection surfaces 31 and torque detectors 32 each having shape magnetic anisotropy in the same direction may be provided to thicken the detection output. However, the detection accuracy may be further improved.

Furthermore, in the embodiment described above, groups a, . . .

Although the inclination angles of a,..., b are set to +45 degrees and -45 degrees, respectively, the present invention is not necessarily limited to this, and for example, the inclination angles may be opposite to each other, Further, the angle may be other than 45 degrees depending on the needs of processing and the like.

Furthermore, in the measurement unit 33 described above, the case where the output voltage according to the rotational torque is measured has been explained, but the output voltage is digitized and processed by a microcomputer,
It can also perform powertrain-related gear shift control.

By the way, in the present invention, the groups are provided obliquely as the magnetic flux direction defining means constituting the shape magnetic anisotropy.
As a variation of this, a group of non-magnetically permeable members may be embedded to reduce leakage of magnetic flux and to make the diagonal passage of magnetic flux more reliable.

Further, in the above embodiment, a case has been described in which the torque detection surface is formed directly on the output shaft, but the present invention is not limited to this. It may be attached to.

Furthermore, not only when the rectifier circuits 44A and 44B are used as the measuring section, but also when an AC differential amplifier is used as the differential amplifier, the output terminals c and d of the bridge circuit 40
may be directly connected to the input side of the differential amplifier, as long as it is configured to be able to detect the balanced state and unbalanced state of the output terminals c and d of the bridge circuit 44.

Furthermore, the automatic transmission is not limited to the configuration of the above embodiment, and the present invention can be applied to automatic transmissions with any other configuration.

〔Effect of the invention〕

As explained above, according to the present invention, a torque detection surface is formed on the output side rotating body of a fastening element of an automatic transmission, and a torque detector having a detection coil is placed facing the torque detection surface on the transmission case side. Because it is arranged on the member, it is possible to detect the rotational torque transmitted by the fastening element near the transmission part, and the rotational torque transmitted in a non-contact state and generated when the fastening element is fastened. It is possible to accurately detect torque fluctuations due to shift shocks, and to reduce the delay in detecting torque fluctuations due to shift shocks. Therefore, the torque detection value of the torque detection device is used to control the shift of automatic transmissions. In this case, a suitable torque detection device can be provided.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a partially enlarged view of the main part of Fig. 1, Fig. 3 is a sectional view taken along the line mm in Fig. 1, and Fig. 4 is Schematic diagram of the automatic transmission in Figure 1, Figure 5
The figure is a block diagram showing an example of the measurement unit, Figure 6 is a developed view showing the torque detection surface formed on the drum, Figure 7 is an explanatory diagram showing the state of the magnetic field generated by the coil, and Figure 8 is the torque detection device. FIG. 3 is a characteristic diagram showing the relationship between torque and output voltage. In the figure, 1 is the transmission case, 6 is the input shaft, and 8
is the rear planetary gear, 9 is the front planetary gear, 10 is the high clutch, 10a is the clutch drum, 1
1 is a reverse clutch, 12 is a band brake, 13 is a forward one-way clutch, 14 is a forward clutch, 15 is an overrun clutch, 16 is a low and reverse brake, 17 is a row one-way clutch, 1
8 is an output shaft, 21 is a rotating drum, 30A, 30B. 30C is a torque detection device, 31 is a torque detection surface, 32 is a torque detector, 33 is a measuring section, 34A, 34B are group columns, 35A, 35B are coils, 40 is a bridge circuit,
45 is a differential amplifier.

Claims (1)

[Claims] In an automatic transmission in which driving force from an engine is transmitted via an input shaft, the driving force is automatically shifted and transmitted to an output shaft by appropriately selecting a plurality of fastening elements, and an output side rotating member of the fastening element. A torque detection surface having shape magnetic anisotropy is formed on the outer peripheral surface of the automatic transmission, and a torque detector having a detection coil is mounted on a transmission case side member facing the torque detection surface. Detection device.