JP2020193665A - Friction fastening device - Google Patents

Abstract

To achieve a high-performance friction fastening device which enables the temperature of the friction plates thereof to be acquired with a high degree of accuracy.SOLUTION: A friction fastening device 6 is provided that comprises: two groups of friction plates 30, 40 arranged alternately in the axial direction; a piston 50 that advances toward and retracts from the plate groups to switch the fastening state of the plate group between a fastened state and a not-fastened state; and a temperature sensor 90 that detects the temperature of the plate groups. Each of the end plates at both ends of the plate groups is composed of a movable end plate 30a that is located on the side of the piston 50 and is provided to be axially movable, and a regulation end plate 30b provided to be axially immovable. The temperature sensor 90 has a linear temperature detection unit 91, and the temperature detection unit 91 is arranged on the regulation end plate to extend along the plate surface.SELECTED DRAWING: Figure 7

Description

The technology to be disclosed relates to a friction fastening device provided in a transmission or the like, which constitutes a clutch, a brake or the like.

Generally, this type of friction fastening device is provided with a friction plate including a plurality of drive plates and a plurality of driven plates. Each of the drive plate and the driven plate is connected to each of, for example, a hub and a drum, and is arranged alternately in the plate thickness direction so as to be slidable with each other. In the case of wet friction fastening devices, lubricating oil (ATF) is supplied between these friction plates during use.

When these friction plates are pressed by the piston so as to be in close contact with each other, the hub and the drum are in a state of being connected to each other (fastened state). By removing the pressing force so that these friction plates are separated from each other, the hub and the drum are in a state of operating independently of each other (non-fastened state).

As a conventional example of such a friction fastening device, there is, for example, Patent Document 1. It discloses a friction engaging device in which a spring clip is attached to each friction plate, and the elastic force thereof urges each friction plate to separate when the friction plate is switched to the non-fastened state.

Japanese Unexamined Patent Publication No. 2003-13996

Generally, in such a friction fastening device, the amount of power transmitted is controlled by adjusting the pressing force of the piston. In the fastened state, frictional heat is generated because the plate surface of the friction plate is in sliding contact while there is a difference in the amount of rotation between the hub and the drum. Normally, both the driven plate and the drive plate are thin plates, and their frictional heat raises their temperatures.

On the other hand, a predetermined heat resistant temperature (temperature upper limit value at the time of use) that can be properly used is set in advance in these friction plates. Therefore, the friction fastening device needs to prevent the temperature of the friction plate from exceeding its heat resistant temperature.

Therefore, conventionally, the temperature of the friction plate is estimated based on the map or calculation formula set in advance based on the experimental results and the indirect information such as the rotation speed of the friction plate, and the temperature is estimated to be the temperature. Based on this, the operation of the friction fastening device is controlled so as not to exceed the heat resistant temperature.

However, the temperature estimate of the friction plate based on such indirect information has a large error and low accuracy. Therefore, in order to properly use the friction fastening device, there is no choice but to control the operation of the friction fastening device under a temperature upper limit value having a margin in consideration of the error. As a result, the friction fastening device has a problem that the original performance cannot be sufficiently exhibited.

Therefore, the main purpose of the technology disclosed is to realize a high-performance friction fastening device capable of detecting the temperature of the friction plate with high accuracy.

The technique disclosed relates to a friction fastening device that switches the transmission of power output to a rotating shaft.

The friction fastening device includes two groups of friction plates that are engaged with each of the two connecting members and that form a group of plates that are alternately arranged in the axial direction with the plate surfaces facing each other, and the plates from one of the axial directions. A piston that switches the engagement state of the plate group between a fastened state in which each of the friction plates is in close contact with each other and a non-fastened state in which each of the friction plates is separable. To be equipped.

Each of the end plates at both ends of the plate group includes a movable end plate that is located on the side of the piston and is provided so as to be movable in the axial direction, and a regulated end plate that is provided so that the movement in the axial direction is restricted. It is composed of.

Further, a temperature sensor for detecting the temperature of the plate group is further provided, and the temperature sensor has a linear temperature detecting portion extending along the plate surface of the regulated end plate.

That is, in this friction fastening device, the engaged state of the plate group is switched between the engaged state and the non-fastened state by advancing and retreating the piston toward the plate group consisting of the two groups of friction plates. ing. The friction fastening device is provided with a temperature sensor that detects the temperature of the plate group, regulates the movement of the end plate at one end of the plate group, and then detects the linear temperature of the temperature sensor. The portions are arranged on the regulated end plate so as to extend along the plate surface.

Each of the friction plates constituting the plate group can move in the axial direction as the engaging state of the plate group is switched, but the axial movement of the regulated end plate is restricted. Therefore, according to the linear temperature detection unit extending along the plate surface of the regulated end plate, the temperature of the friction plate during operation can be detected with a small error without being affected by the movement of the friction plate. As a result, the temperature sensor can measure the temperature of the plate group with high accuracy in a structurally stable state. Therefore, a high-performance friction fastening device can be realized.

The friction fastening device may also have an annular groove extending in the circumferential direction formed on the plate surface of the regulation end plate, and the temperature detecting portion may be embedded in the annular groove.

The temperature detector is then integrated with the regulated end plate. Therefore, vibration accompanying the operation of the friction fastening device can be suppressed, and more stable and highly accurate temperature detection can be performed. Since the mounting strength of the temperature detection unit is also strengthened, the durability is also improved.

The friction fastening device may also have the temperature detection unit arranged on the plate surface on the side not in contact with the friction plate.

By doing so, it is possible to avoid direct contact with the temperature detection unit due to the operation of the friction fastening device. Therefore, it is possible to avoid adversely affecting the performance of the friction fastening device, and it is possible to secure a high degree of durability.

In the friction fastening device, the temperature detecting portion is embedded and fixed in the annular groove by a predetermined adhesive, and a high thermal conductive material having a higher thermal conductivity than the adhesive is mixed in the adhesive. It may be.

By embedding with an adhesive, the temperature detector can be firmly fixed to the regulated end plate relatively easily. However, the thermal conductivity of the adhesive is generally not high. Therefore, the temperature transmitted from the surface of the friction plate to the temperature detection unit via the adhesive may be delayed, and the accuracy of temperature detection may deteriorate. On the other hand, if a high thermal conductive material is mixed with the adhesive, such defects can be reduced, so that highly accurate temperature detection becomes possible.

It is preferable to use an optical fiber for the temperature detection unit.

If an optical fiber is used for the temperature detection unit, a plurality of temperatures can be detected in a short time at an arbitrary position of the temperature detection unit by injecting a predetermined pulsed light into the temperature detection unit. That is, the temperature at a plurality of locations in the circumferential direction of the regulation end plate can be efficiently measured in a short time.

Since the wire diameter of an optical fiber can be minimized, even a friction plate having a thickness of several mm can be arranged with a margin. Moreover, since the transmission is performed by light and the heat capacity is extremely small, extremely high responsiveness can be obtained.

When an optical fiber is used for the temperature detection unit, a control device for controlling the operation of the friction fastening device based on the detection value of the temperature sensor is further provided, and the control device is based on the pressing force of the piston. It may have a temperature correction unit that corrects the detection value of the temperature sensor.

In the fastened state, the pressing force of the piston acts on the regulating end plate, and the pressing force may deform the regulating end plate. Therefore, when an optical fiber is used for the temperature detection unit, the optical fiber may be distorted due to the pressing force.

On the other hand, there is a reproducible correlation between the pressing force of the piston and the strain amount of the optical fiber. Therefore, in this friction fastening device, the control device that controls the operation is provided with a temperature correction unit that corrects the detected value of the temperature sensor based on the pressing force of the piston.

Therefore, according to this friction fastening device, even if the pressing force of the piston changes depending on the magnitude and an error occurs in the detected value of the temperature sensor, it can be corrected to an appropriate value. Therefore, it becomes possible to detect the temperature of the plate group with higher accuracy.

According to the disclosed technique, the temperature of the friction plate can be detected with high accuracy, so that a high-performance friction fastening device can be realized.

It is the schematic which shows the transmission suitable for the disclosed technology and the related apparatus. The enlarged view is a schematic cross-sectional view of the clutch portion. It is a simplified view of the clutch corresponding to the enlarged view of FIG. It is a schematic perspective view which shows the assembly structure of the main member of a clutch. It is the schematic for demonstrating the operation of a clutch. It is a block diagram which shows the input / output relationship between TCM and its main related apparatus. It is a graph which showed the time-dependent change of the main element when a clutch slips at the time of acceleration of an automobile. It is the schematic which shows the specific example of the improved clutch to which the disclosed technique is applied. It is a figure for demonstrating the structure of the regulation end plate. It is a figure for demonstrating the structure of the regulation end plate. It is the schematic which shows the structure of the main part of a temperature sensor. It is a graph which showed the effect of the improved clutch corresponding to FIG. It is a block diagram which shows the input / output relationship between TCM in an improved clutch and its main related device. It is a block diagram which shows the input / output relationship between a TCM and its main related device in an application example (the second improved clutch). It is a graph for demonstrating the effect of the 2nd improved clutch. It is the schematic which shows the modification of the improved clutch.

Hereinafter, embodiments of the disclosed technology will be described in detail with reference to the drawings. However, the following description is essentially merely an example and does not limit the present invention, its application or its use.

In the description, the direction in which the output shaft 3, which will be described later, extends is defined as the "axial direction", the direction of the radius or diameter centered on the output shaft 3 is defined as the "diametric direction", and the direction in which the output shaft 3 is rotated is defined as the "circumferential direction". And. Further, in the axial direction, the side where the power is input to the transmission 1 described later is referred to as the “input side”, and the side where the power is output from the transmission 1 is referred to as the “output side”.

<Transmission>
FIG. 1 illustrates a transmission 1 (automatic transmission) suitable for the disclosed technology. The transmission 1 is mounted on an automobile. The transmission 1 is interposed between the engine E (which may be a motor) which is a drive source and the wheels W, and accelerates or decelerates the rotational power output from the engine E and outputs the rotational power to the wheels.

An exemplary transmission 1 is a multi-speed automatic transmission (so-called AT). The application target of the disclosed technology is not limited to transmission 1. It can be applied as long as it has a friction fastening device.

The transmission 1 is composed of a housing 2, an output shaft 3 (rotating shaft), a transmission 4, an intermittent device 5, and the like. The housing 2 constitutes the outer shell of the transmission 1, accommodates the intermittent device 5 and the transmission device 4, and supports the output shaft 3 in a rotatable state.

The intermittent device 5 (so-called torque converter) is connected to the engine E, and the rotational power output by the engine E is input to the transmission 1 as needed. The transmission 4 is arranged around the output shaft 3 and is interposed between the intermittent device 5 and the output shaft 3. The transmission 4 switches the rotation speed of the rotational power input from the intermittent device 5 and transmits it to the output shaft 3. The rotational power output from the transmission 1 through the output shaft 3 is transmitted to the wheels W.

A plurality of planetary gear mechanisms are incorporated in the transmission 4 in order to switch the output rotation speed. The transmission 4 also incorporates a clutch or brake (friction fastening device 6) for switching between these planetary gear mechanisms. The transmission 1 executes forward, backward, and switching of rotational speed by changing the operating state of these clutches or brakes.

(Structure of friction fastening device 6)
Although the clutch and the brake are functionally different, they are structurally almost the same (hereinafter, the friction fastening device 6 will be described as a clutch).

FIG. 1 shows an enlarged part of the clutch 6 included in the transmission 4. At the same time, a simplified diagram corresponding to this is shown in FIG. The illustrated clutch 6 includes a drum 10 and a hub 20 as "connecting members" (for example, if one of the drum 10 and the hub 20 is structurally non-rotatable, it becomes a brake). In addition to these drums 10 and hubs 20, the main body of the clutch 6 is composed of a plurality of driven plates 30 (friction plates), a plurality of drive plates 40 (friction plates), a piston 50, and the like.

The clutch 6 also includes a TCM 8 (Transmission Control Module, control device). As shown in FIG. 1, the TCM 8 is installed separately from the main body portion of the clutch 6, and drives the main body portion of the clutch 6 by hydraulic control or electric control.

(Drum 10, hub 20)
As shown briefly in FIG. 3, the drum 10 is composed of a bottomed cylindrical member having a cylindrical peripheral wall portion 10a and a disk-shaped bottom wall portion 10b through which the output shaft 3 penetrates the central portion. .. The drum 10 is arranged coaxially with the output shaft 3 inside the housing 2 with its bottom wall portion 10b facing the output side. The hub 20 is made of a member having a cylindrical portion (hub shaft portion 20a) having a diameter smaller than that of the drum 10. The hub shaft portion 20a is housed inside the drum 10 and is arranged coaxially with the output shaft 3.

The drum 10 and the hub 20 are supported by the housing 2 in a state in which they can rotate independently. Each of the drum 10 and the hub 20 is directly or indirectly connected to either the output shaft 3 or the transmission 4. In the clutch 6, the drum 10 is connected to the output shaft 3, and the hub 20 is connected to the transmission 4.

The inner peripheral surface of the peripheral wall portion 10a of the drum 10 and the outer peripheral surface of the hub shaft portion 20a face each other in the radial direction (opposing surfaces), and an annular space (plate accommodating chamber 60) is provided between these facing surfaces. ) Is provided. When the transmission 1 is operated, the plate accommodating chamber 60 is provided with an oil introduction path 7a and a housing 2 formed in the hub shaft portion 20a from a lubrication device 7 (shown only in FIG. 2) including an oil storage tank and a hydraulic pump. Lubricating oil (ATF: Automatic Transmission Fluid) is circulated and supplied at a constant flow rate during operation through the oil supply passage 7a formed inside (so-called wet type).

The ATF supplied to the plate accommodating chamber 60 is returned to the lubricator 7 through the oil outlet path 7b formed in the peripheral wall portion 10a of the drum 10 and the oil return path 7b formed inside the housing 2.

A plurality of first fitting grooves 11 extending in the axial direction are formed on the inner peripheral surface of the peripheral wall portion 10a of the drum 10. The first fitting grooves 11 are arranged at intervals in the circumferential direction. In the drum 10 of the present embodiment, the input-side end of each first fitting groove 11 is open (open end 11a). On the other hand, the output side end is closed by the bottom wall portion 10b (sealing end 11b).

A plurality of second fitting grooves 21 extending in the axial direction are also formed on the outer peripheral surface of the hub shaft portion 20a. The second fitting grooves 21 are also arranged at intervals in the circumferential direction.

(Driven plate 30, drive plate 40)
As shown in FIG. 3, each driven plate 30 is made of an annular plate member made of metal. On the outer peripheral edge of each driven plate 30, a plurality of first fitting pieces 31 that are slidably fitted to each first fitting groove 11 are formed so as to project. By fitting the first fitting piece 31 into the first fitting groove 11 from the open end 11a, each driven plate 30 is attached to the drum 10 and is slidable in the axial direction (so-called spline fitting). ).

As shown in FIG. 3, each drive plate 40 is made of an annular plate member made of metal, which is thinner than the drive plate 40. A plurality of second fitting pieces 41 are formed so as to project from the inner peripheral edge of each drive plate 40. Each drive plate 40 is also attached to the hub 20 in a state where it can freely slide in the axial direction by fitting the second fitting piece 41 into the second fitting groove 21 (spline fitting).

A group of driven plates 30 and a group of drive plates 40 are housed in a plate accommodating chamber 60 in a state where the plate surfaces are opposed to each other and arranged alternately in the axial direction (the friction plates of these two groups are put together and "" Also called "plate group").

In this clutch 6, the driven plates 30 are arranged so as to be located at both ends in the axial direction of the plate group (the driven plates 30 at the ends on the output side are also referred to as output side end plates 30a, and are located at the ends on the input side. The existing driven plate 30 is also referred to as an input side end plate 30b). In the clutch 6 of the present embodiment, a driven plate 30 (also referred to as a retainer plate 30b) having a thickness larger than that of the other driven plates 30 is used for the input side end plate 30b.

A ring groove 12 extending in the circumferential direction is formed in a portion of the drum 10 in the vicinity of the open end 11a of each first fitting groove 11. An arc-shaped snap ring 70 having elasticity is fitted in the ring groove 12.

By fitting the snap ring 70 into the ring groove 12, the open end 11a of each first fitting groove 11 is sealed. When the retainer plate 30b slides toward the input side, it comes into contact with the snap ring 70 and is received by the snap ring 70. As a result, the movement of the retainer plate 30b to the input side is restricted (prevented).

(Piston 50)
As shown in FIGS. 1 and 2, a piston 50 that slides in the axial direction is arranged at the back of the drum 10, that is, on the output side of the plate accommodating chamber 60. The piston 50 of the present embodiment is integrally composed of a pressing portion 50a, an operating portion 50b, and the like.

The pressing portion 50a is located in the plate accommodating chamber 60, and is further arranged on the output side of the plate group. The pressing portion 50a is arranged so as to face the output side end plate 30a in the axial direction. On the other hand, the operating portion 50b is located inside the hub 20, and is arranged between the spring 51 provided on the input side and the hydraulic chamber 52 provided on the output side. The hydraulic chamber 52 is partitioned in a liquidtight manner by the operating portion 50b.

The operating portion 50b is urged toward the output side by the elastic force of the spring 51. The hydraulic oil HF pressurized by the hydraulic pump 53 is supplied or discharged to the hydraulic chamber 52. As a result, the moving unit 50b is configured to move in the axial direction by applying flood control to the operating unit 50b.

That is, when the hydraulic oil HF is supplied from the hydraulic pump 53 to the hydraulic chamber 52, the operating portion 50b slides to the input side against the elastic force of the spring 51. When the hydraulic oil HF is discharged from the hydraulic chamber 52, the operating portion 50b slides to the output side due to the elastic force of the spring 51. The operating portion 50b slid to the output side is received by the bottom wall portion 10b of the drum 10. As a result, the movement of the operating portion 50b is restricted (blocked).

With the movement of the operating portion 50b by such hydraulic control, the piston 50 moves in the plate accommodating chamber 60 and moves back and forth from the output side toward the plate group.

(Operation of friction fastening device 6)
The TCM 8 switches the clutch 6 by hydraulic control in order to switch between the connected state and the unconnected state of the hub 20 and the drum 10 according to the traveling state of the automobile.

Specifically, the TCM 8 changes the supply state and the discharge state of the hydraulic oil HF to the hydraulic chamber 52 by controlling the flow of the hydraulic oil HF supplied by the hydraulic pump 53 by a valve or the like. By doing so, as shown in FIG. 4, the driven plate 30 and the drive plate 40 are in close contact with each other (fastened state), and the driven plate 30 and the drive plate 40 are separated from each other (non-fastened state). The engagement state of the plate group is switched between the state) and the state).

That is, when the hydraulic oil HF is supplied to the hydraulic chamber 52, the piston 50 moves to the input side as shown in the left figure of FIG. As a result, a pressing force is applied to the plate group to bring the plate into a fastened state. In the fastened state, the plate group including the retainer plate 30b is received by the snap ring 70, and the piston 50 is located on the input side most.

On the other hand, when the hydraulic oil HF is discharged from the hydraulic chamber 52, the piston 50 moves to the output side by the elastic force of the spring 51 as shown in the right figure of FIG. As a result, the piston 50 is separated from the plate group, the pressing force is removed from the plate group, and the piston 50 is in a non-fastened state. In the non-fastened state, the piston 50 is located on the output side most, so that the distance between the piston 50 and the snap ring 70 is widened, and each of the driven plate 30 including the retainer plate 30b and the drive plate 40 has its own position. It becomes a free state (a state in which it can slide in the axial direction) at widened intervals.

When switching from the non-fastened state to the fastened state, or when switching from the fastened state to the non-fastened state, there is usually a difference in the amount of rotation between the hub 20 and the drum 10. Therefore, the plate surfaces of the driven plate 30 and the plate surfaces of the drive plate 40, which are in contact with each other, are in sliding contact with each other to generate frictional heat. When the amount of frictional heat exceeds the cooling performance by ATF, the temperature of these friction plates rises relatively easily because they are thin plates having a small heat capacity.

A predetermined heat-resistant temperature (temperature upper limit value at the time of use) that can be properly used is set in advance in these friction plates. Therefore, it is necessary to limit the operation of the clutch 6 so that the temperature of the friction plate, specifically the temperature of the friction surface thereof, does not exceed the heat resistant temperature during its use.

Therefore, in the conventional clutch 6, the TCM 8 is configured to estimate the temperature of a predetermined clutch 6 and control the operation of the clutch 6 based on the estimated value. Specifically, as shown in FIG. 5, the TCM 8 has a clutch control unit 8a that controls the operation of the clutch 6 by controlling the hydraulic pressure of the piston 50 and the output of the engine E, and estimates the temperature of the clutch 6 by calculation. A clutch temperature estimation unit 8b is provided.

Various sensors 54, such as an automobile speed sensor and an engine E rotation sensor, are electrically connected to the TCM 8. When the clutch 6 is activated, various information is input to the TCM 8 from these sensors 54. The TCM8 is also electrically connected to a hydraulic sensor 54a (shown only in FIG. 5), and information about the hydraulic pressure for driving the piston 50 is input to the TCM8 from the hydraulic sensor 54a.

Then, the TCM 8 acquires indirect information related to the temperature of the clutch 6 from various sensors 54, and the clutch temperature estimation unit 8b uses these information and a preset calculation formula to determine the temperature of the plate group. presume. Based on the estimated temperature value, the clutch control unit 8a controls the operation of the clutch 6 by adjusting the output of the engine E so as not to exceed the heat resistant temperature.

However, the temperature estimation value of the plate group based on such indirect information has a large error and low accuracy. Therefore, in order to use the clutch 6 stably at an appropriate temperature, the operation of the clutch 6 must be controlled under a temperature upper limit value having a margin in consideration of the error. As a result, the clutch 6 has a problem that the original performance cannot be sufficiently exhibited.

This point will be specifically described by taking as an example the case where the clutch 6 slips when the automobile is accelerated. FIG. 6 shows the acceleration of the automobile, the torque output by the engine E, the rotation speed of the clutch 6 (input rotation speed and output rotation speed), and the temperature of the clutch 6 (estimated temperature value) in such a case. An example of a graph showing changes over time is illustrated.

In the rotation speed of the clutch 6, the broken line indicates the input rotation speed, and the solid line indicates the output rotation speed. At the temperature of the clutch 6, the temperature TL indicates the heat resistant temperature (temperature upper limit value at the time of use) of the plate group.

As shown in FIG. 6, the accelerator is depressed at the timing of t0, so that the automobile is accelerated during traveling. Along with this, the output torque of the engine E is set to a predetermined value according to the acceleration, and the input rotation speed to the clutch 6 is gradually increased accordingly.

At that time, since slip is generated in the clutch 6, the output rotation speed of the clutch 6 is a value lower than the input rotation speed, and is higher following the input rotation speed.

When slip occurs in the clutch 6, frictional heat is generated and the temperature of the clutch 6 rises. At this time, if the temperature of the clutch 6 is an indirectly acquired temperature estimated value, an error is involved. The width R shown in FIG. 6 indicates the variation width of the error. Therefore, in order to maintain the temperature of the clutch 6 below the heat resistant temperature TL with high accuracy, it is necessary to control the operation of the clutch 6 in consideration of at least the variation width.

Therefore, the TCM 8 determines that the temperature of the clutch 6 has reached the limit at the timing of t1 when the upper limit of the variation width of the estimated temperature value reaches the heat resistant temperature TL, and reduces the output torque of the engine E. As a result, the input rotation speed of the clutch 6 decreases, the difference from the output rotation speed gradually decreases, slip is eliminated, and the generation of frictional heat is suppressed.

On the other hand, the acceleration of the automobile changes suddenly at the timing of t1. Moreover, the acceleration drops from the value set according to the depression of the accelerator, and the desired acceleration state cannot be obtained.

Therefore, in the disclosed technology, high-precision control of the clutch 6 is realized by devising so that the temperature of the clutch 6 can be directly measured.

<Application of disclosed technology>
The technology to be disclosed will be specifically described by applying it to the clutch 6 described above.

FIG. 7 shows a clutch 6 (also referred to as an improved clutch 6) to which the disclosed technology is applied. In the improved clutch 6, first, the output side end plate 30a located on the side of the piston 50 is provided so as to be movable in the axial direction (movable end plate). The retainer plate 30b located on the opposite side thereof is provided so that it cannot move in the axial direction and is restricted from moving in the axial direction (regulated end plate).

(Movable end plate, regulated end plate)
The movable end plate and the restricting end plate are provided with a movement restricting portion at the end on the input side of the first fitting groove 11, and the movement restricting portion is the input side end that is finally fitted into the first fitting groove 11. It is configured by restricting the sliding of the plate (retainer plate 30b) to the output side.

Specifically, as shown in FIGS. 8 and 9, a small protrusion 80 projecting inward is formed on the inner wall surface of the first fitting groove 11 near the open end 11a. The protrusion 80 is formed on the output side of the ring groove 12, and is formed so as to have a space slightly larger than the thickness of the retainer plate 30b between the protrusion 80 and the ring groove 12.

At the same time, as shown in FIG. 9A, of the plurality of driven plates 30, the driven plates 30 other than the retainer plate 30b are fitted into the first fitting groove 11 in which the protrusion 80 is formed. A notch 81 for avoiding contact with the protrusion 80 is formed on the first fitting piece 31.

In this transmission 1, when the driven plate 30 is assembled to the drum 10, each driven plate 30 including the output side end plate 30a is arranged alternately with the drive plate 40, and each first fitting piece 31 is placed on the first first. It is fitted into the fitting groove 11 and mounted on the drum 10. At that time, even if the protrusion 80 is formed in the first fitting groove 11, each driven plate 30 can be mounted on the drum 10 without any trouble because the notch 81 is formed in each driven plate 30.

As a result, the output side end plate 30a is mounted on the drum 10 in a state of being movable in the axial direction, and constitutes a movable end plate.

On the other hand, as shown in FIG. 9B, the retainer plate 30b into which each first fitting piece 31 is finally fitted into each first fitting groove 11 is not formed with a notch 81. Therefore, the retainer plate 30b is restricted from sliding toward the output side by the protrusion 80. That is, the protrusion 80 constitutes a movement restricting portion, and the protrusion 80 restricts the movement of the retainer plate 30b to the output side. The retainer plate 30b also constitutes a regulated end plate because movement to the input side is restricted by the snap ring 70.

(Temperature sensor)
As a result, the retainer plate 30b whose movement in the axial direction is restricted incorporates a temperature sensor 90 that detects the temperature of the plate group. The temperature sensor 90 has a linear temperature detection unit 91, and the temperature detection unit 91 is arranged on the retainer plate 30b so as to extend along the plate surface.

Specifically, as shown in FIGS. 7 and 10, among the plate surfaces of the retainer plate 30b, on the plate surface (anti-friction surface 32) opposite to the surface (friction surface) in contact with the adjacent drive plate 40. A groove extending in an annular shape in the circumferential direction (annular groove 92) and a groove extending from the annular groove 92 so as to be gently inclined outward in the radial direction (leading groove 93) are formed. The annular groove 92 is formed in a region on the friction surface opposite to the region in contact with the drive plate 40.

A linear temperature detection unit 91 is arranged in the annular groove 92 so as to extend over substantially the entire circumference, and is led out to the outside of the retainer plate 30b through the lead-out groove 93. The temperature detection unit 91 led out from the retainer plate 30b is drawn out of the transmission 1 and connected to the temperature conversion device 94. The temperature conversion device 94 converts the temperature information detected by the temperature detection unit 91 into an electric signal and outputs the information to the TCM 8.

Since the temperature detection unit 91 is provided on the anti-friction surface 32, there is no possibility of affecting the engagement between the retainer plate 30b and the drive plate 40 due to friction. Therefore, there is no risk of functional deterioration of the clutch 6. Since no frictional force acts on the temperature detection unit 91, there is no possibility that the durability will be lowered by installing the temperature detection unit 91.

In this embodiment, one optical fiber is used for the temperature detection unit 91. The optical fiber is introduced into the annular groove 92 through the lead-out groove 93, and is arranged so as to orbit the annular groove 92 and its tip is located in the vicinity of the lead-out groove 93. By injecting a predetermined pulsed light into the optical fiber, the temperature at an arbitrary position of the optical fiber can be detected.

The temperature detection technique using an optical fiber is known. Briefly explaining the principle of temperature detection, when pulsed light is incident on an optical fiber, the pulsed light propagates in the optical fiber while being scattered and attenuated. Then, a part of the scattered light returns to the end portion (incident end) where the pulsed light is incident.

Therefore, it is possible to specify the position where the scattering occurs from the time until the pulsed light is incident from the incident end and the scattered light returns, and the temperature at the specified position can be determined from the intensity of the scattered light. It becomes possible to detect.

That is, according to the optical fiber, a large number of temperatures can be detected at any position in the range simply by arranging one in the range where the temperature is desired to be detected. Moreover, a plurality of temperatures can be detected in an extremely short time. Therefore, it is possible to measure the temperature at a plurality of locations in the circumferential direction of the retainer plate 30b.

In the clutch 6, the plate group is cooled by the ATF, but the state in which the ATF comes into contact with the friction plate is constantly changed depending on the rotation speed of the engine E, the inclination of the automobile, and the like. Therefore, the temperature of the friction plate varies greatly depending on the portion, and it is necessary to detect the temperature at as many locations as possible in order to perform highly accurate temperature control. Therefore, an optical fiber capable of detecting the temperature of the entire area of the friction plate is suitable for the temperature detecting unit 91.

Further, if it is an optical fiber, its wire diameter can be minimized. For example, if an optical fiber having a wire diameter of 100 μm is used, even a friction plate having a thickness of several mm can be arranged with a margin. Moreover, since the transmission is performed by light and the heat capacity is extremely small, extremely high responsiveness can be obtained.

On the other hand, in the case of an optical fiber, an error occurs due to distortion. Therefore, in order to detect the temperature with high accuracy by the optical fiber, it is necessary to suppress vibration and deformation. On the other hand, since the retainer plate 30b is restricted from moving in the axial direction, even if the optical fiber is pulled out from the retainer plate 30b, the optical fiber is not significantly deformed and vibration can be suppressed.

Further, as shown in FIGS. 7 and 10, the optical fiber is embedded and fixed in the annular groove 92 and the lead-out groove 93 by a predetermined adhesive 95. That is, it is integrated with the retainer plate 30b. Therefore, it is possible to make the vibration more resistant and suppress the distortion of the optical fiber.

As the adhesive 95, for example, a phenol resin (thermosetting resin) can be used. A phenol resin is suitable for the adhesive 95 because it has excellent heat resistance and is also used as a friction material.

However, the thermal conductivity of the adhesive 95 is not high. Therefore, the responsiveness of the temperature detection of the optical fiber may be deteriorated. Therefore, it is preferable to mix a predetermined amount of a material having a higher thermal conductivity (high thermal conductivity material), for example, metal powder, carbon powder, carbon fiber, etc., into the adhesive material 95. By doing so, the responsiveness of temperature detection can be further enhanced, and the temperature detection accuracy can be improved.

Similar to the clutch 6 described above, the effect of the improved clutch 6 will be specifically described by taking as an example a case where the vehicle slips when accelerating. FIG. 11 shows a diagram corresponding to FIG.

During the operation of the improved clutch 6, the temperatures at a plurality of locations around the retainer plate 30b are directly detected by the temperature detection unit 91. Then, the detected temperature information is output to the temperature measuring device 94, then converted into an electric signal and output to the TCM8.

FIG. 12 shows the TCM 8 corresponding to the improved clutch 6. In the improved clutch 6, since the measured value of the temperature of the clutch 6 is input to the TCM 8, the clutch temperature estimation unit 8b is omitted. The clutch control unit 8a determines whether the maximum temperature of the friction plate reaches the heat resistant temperature TL or less based on the temperature detection value of the friction plate input from the temperature sensor 90.

In the improved clutch 6, since the temperature of the friction plate is actually measured, the error is very small as compared with the estimated temperature value. Therefore, as shown in FIG. 11, the clutch control unit 8a determines that the temperature of the clutch 6 has reached the limit at the timing of t2 when the temperature detection value (maximum value) reaches the heat-resistant temperature TL, and the engine E determines that the temperature has reached the limit. Reduce the output torque.

As a result, it becomes possible to optimize the timing at which the acceleration of the automobile decreases, and it is possible to significantly delay it. Due to the temperature of the clutch 6, the operating conditions are less frequently restricted, and the original performance of the automobile can be improved.

<Application example>
A clutch 6 (also referred to as a second improved clutch 6) that can obtain the temperature of the friction plate with higher accuracy and further improve the performance from the improved clutch 6 described above will be described.

In the fastened state, the pressing force of the piston 50 acts on the retainer plate 30b. The retainer plate 30b may be deformed by the pressing force. Therefore, when an optical fiber is used for the temperature detection unit 91, the optical fiber may be distorted due to the pressing force. On the other hand, there is a reproducible correlation between the pressing force of the piston 50 and the amount of distortion of the optical fiber.

Therefore, in the second improved clutch 6, the TCM 8 is provided with a temperature correction unit 8c that corrects the detection value of the temperature sensor 90 based on the pressing force of the piston 50. FIG. 13 shows the TCM 8 and its related devices corresponding to the second improved clutch 6.

The correlation between the pressing force of the piston 50 and the amount of strain of the retainer plate 30b has been investigated in advance by experiments and the like. A correction map (temperature correction information) capable of deriving a temperature correction amount from the pressing force based on the correlation is set in the temperature correction unit 8c.

The temperature compensation unit 8c acquires the pressing force of the piston 50 based on the information of the flood pressure input from the oil pressure sensor 54a. By collating the acquired pressing force with the correction map, the temperature correction unit 8c acquires a temperature correction amount corresponding to the pressing force. Then, the temperature correction unit 8c acquires a temperature correction value in consideration of distortion due to the pressing force by performing arithmetic processing for adding or subtracting the correction amount of the temperature to the temperature detection value input from the temperature sensor 90.

FIG. 14 shows the relationship between the temperature of the clutch 6 and the pressing force of the piston 50. In FIG. 14, the thin line T0 shows the actual temperature of the clutch 6, and the broken line T1 shows the temperature detected value by the temperature sensor 90 before correction. As the pressing force of the piston 50 increases, the distortion of the optical fiber also increases, and the temperature detected value of the temperature sensor 90 gradually deviates from the actual temperature.

On the other hand, the thick line T2 in FIG. 14 shows the case where the temperature is corrected by the second improved clutch 6. Due to the temperature correction by the temperature correction unit 8c, the temperature correction value is almost the same as the actual temperature. Therefore, in the second improved clutch 6, even if the pressing force of the piston 50 changes depending on the magnitude, the temperature of the clutch 6 can be detected with high accuracy.

As described above, according to the disclosed technique, the temperature of the plate group can be obtained with high accuracy, so that the high-performance clutch 6 can be realized.

The friction fastening device according to the disclosed technique is not limited to the above-described embodiment, and includes various other configurations.

For example, in the clutch 6 described above, the retainer plate 30b is used as the regulated end plate, but depending on the form of the friction fastening device, the friction plate located at the back of the drum may be used as the regulated end plate.

A specific example thereof is shown in FIG. The piston 50 is arranged on the opening side of the drum 10. A predetermined plate (end plate 100) is attached to the bottom wall portion 10b of the drum 10. The end plate 100 is not essential.

Then, the temperature detection unit 91 is arranged on the output side end plate 30a which is arranged at the innermost part of the drum 10. Then, the output side end plate 30a is fixed to the end plate 100 to form the regulation end plate (if the end plate 100 is not present, it is fixed to the bottom wall portion 10b).

In addition, for example, in the temperature sensor 90 described above, although the optical fiber is shown as the temperature detection unit 91, it may be a thermocouple. However, when a thermocouple is used, the temperature detection points are limited. Further, the temperature detection unit 91 is preferably arranged on the anti-friction surface 32, but may be arranged on the friction surface. Instead of burying the temperature detection unit 91 with the adhesive 95, the temperature detection unit 91 may be attached to the friction plate with metal by a vapor deposition process or the like.

1 Transmission 3 Output shaft (rotary shaft)
4 Transmission 5 Intermittent device 6 Friction fastening device (clutch)
8 TCM
8a Clutch control unit 8c Temperature compensation unit 10 Drum 20 Hub 30 Driven plate (friction plate)
30a Output side end plate 30b Input side end plate (retainer plate)
40 drive plate (friction plate)
50 Piston 60 Plate storage chamber 90 Temperature sensor 91 Temperature detector 95 Adhesive

Claims (6)

A friction fastening device that switches the transmission of power output to the rotating shaft.
Two groups of friction plates that are engaged with each of the two connecting members and that form a group of plates that are arranged alternately in the axial direction with the plate surfaces facing each other.
The engagement of the plate group is between a fastened state in which each of the friction plates is in close contact with each other and a non-fastened state in which each of the friction plates is separable by advancing and retreating from one of the axial directions toward the plate group. A piston that switches the mating state and
With
Each of the end plates at both ends of the plate group includes a movable end plate that is located on the side of the piston and is provided so as to be movable in the axial direction, and a regulated end plate that is provided so that the movement in the axial direction is restricted. Consists of
Further equipped with a temperature sensor for detecting the temperature of the plate group,
A friction fastening device in which the temperature sensor has a linear temperature detection unit extending along a plate surface of the regulation end plate. In the friction fastening device according to claim 1,
A friction fastening device in which an annular groove extending in the circumferential direction is formed on the plate surface of the regulation end plate, and the temperature detecting portion is embedded in the annular groove. In the friction fastening device according to claim 2,
A friction fastening device in which the temperature detection unit is arranged on the plate surface on the side not in contact with the friction plate. In the friction fastening device according to claim 2 or 3.
A friction fastening device in which the temperature detection unit is embedded and fixed in the annular groove by a predetermined adhesive, and a high thermal conductivity material having a higher thermal conductivity than the adhesive is mixed in the adhesive. .. In the friction fastening device according to any one of claims 1 to 4.
A friction fastening device in which an optical fiber is used for the temperature detection unit. In the friction fastening device according to claim 5,
Further, a control device for controlling the operation of the friction fastening device based on the detected value of the temperature sensor is provided.
A friction fastening device in which the control device has a temperature correction unit that corrects a detection value of the temperature sensor based on a pressing force of the piston.

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