Electric friction engagement device, contact point detection method therefor, and abnormality detection method therefor

Abstract

[Problem] To achieve a structure capable of detecting a piston contact point and a clutch contact point. In order to solve the problem, a phase (theta) related to the rotation direction of a drive cam (34) when the output torque (T) or the current value (A) of a shift motor (66) starts to increase at an increase rate equal to or greater than a first threshold value when an electric friction engagement device (7) is switched from a connection mode to a disconnection mode is detected as a piston contact point (theta p). And detects, as a clutch contact point ([theta] f), a phase ([theta]) related to the rotation direction of the drive cam (34) when the increase rate is equal to or less than a second threshold value.

Description

Technical Field

[0001] The present invention relates to an electric friction engagement device which uses a shift motor as a driving source and switches between a connection mode in which torque is transmitted between a first component and a second component and a disconnection mode in which torque is not transmitted. Background Art

[0002] In rotating mechanical devices such as automobiles and machine tools, a transmission is provided between the power source and the driven object in order to efficiently utilize the output of a power source such as an engine or an electric motor. In the case of a gear-type stepped transmission, a clutch device is assembled between the power source and the transmission to switch between a connection mode in which the output torque of the power source is transmitted to the transmission and a disconnection mode in which the transmission cannot be transmitted. As such a clutch device, a friction clutch that transmits power through friction between mutually opposed friction surfaces, a meshing clutch that transmits power through mutually meshing claws, and the like are used.

[0003] The friction clutch can switch between a connection mode in which torque is transmitted between a pair of rotating members coaxially arranged with each other and a disconnection mode in which torque is not transmitted, regardless of a phase difference or a rotation speed difference between the pair of rotating members coaxially arranged with each other.

[0004] International Publication No. 2008 / 096438 describes a normally open friction clutch that uses a motor as a driving source to switch between a disconnection mode and a connection mode.

[0005] In order to switch the friction clutch described in International Publication No. 2008 / 096438 to the connection mode, the first cam plate is driven to rotate in one direction of the circumference by the motor via the speed reducer and the transmission mechanism, so that the first cam plate is separated from the second cam plate, thereby overcoming the elastic force of the return spring and pressing the moving member. As a result, the driving plate and the driven plate are pressed against each other.

[0006] On the other hand, in order to switch the friction clutch to the disconnection mode, the first cam plate is driven to rotate in the other direction of the circumference by the motor via the speed reducer and the transmission mechanism, so that the first cam plate and the second cam plate approach each other, thereby releasing the force pressing the driving plate and the driven plate against each other. As a result, the gap between the driving plate and the driven plate is widened by the action of the return spring.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: International Publication No. 2008 / 096438 Pamphlet Summary of the invention

[0010] Problems to be solved by the invention

[0011] In the friction clutch described in International Publication No. 2008 / 096438, if the drive plate and the driven plate are worn, when the friction clutch is switched from the connection mode to the disconnection mode, the phase related to the rotation direction of the first cam plate when the fastening force of the friction clutch begins to decrease, i.e., the piston contact point, and the phase related to the rotation direction of the first cam plate when the fastening force is 0, i.e., the clutch contact point, change. Therefore, from the perspective of ensuring good controllability of the friction clutch, it is desirable to detect the piston contact point and the clutch contact point with high accuracy.

[0012] In addition, if the drive plate and the driven plate are used with wear exceeding the usage limit, there is a possibility of causing failures such as seizure. Therefore, from the perspective of ensuring the reliability of the friction clutch, it is also desired to detect the piston contact point and the clutch contact point with high accuracy.

[0013] In view of the above situation, an object of the present disclosure is to realize an electric friction engagement device which can detect a piston contact point and a clutch contact point.

[0014] Means for solving problems

[0015] An electric friction engagement device according to one embodiment of the present disclosure includes a first member, a second member, a friction engagement portion, an elastic urging member, a cam device, and an electric actuator.

[0016] The second member is coaxial with the first member and is supported to be rotatable relative to the first member.

[0017] The friction engagement portion includes at least one first friction plate and at least one second friction plate supported to be relatively displaceable in the axial direction, and is disposed between the first component and the second component. The first friction plate and the second friction plate are pressed against each other to switch to a state in which torque is transmitted between the first component and the second component, and the force pressing the first friction plate and the second friction plate against each other is released to switch to a state in which torque is not transmitted between the first component and the second component.

[0018] The elastic urging member is provided between the first member and the friction engagement portion, and elastically urges the first friction plate and the second friction plate in directions of pressing them against each other.

[0019] The cam device comprises: a driving cam supported to be rotatable relative to the first component and the second component and not to be axially displaceable; and a driven cam supported to be relatively rotatable and axially displaceable relative to the driving cam. As the driving cam rotates, the cam device moves in a direction in which the axial interval between the driven cam and the driving cam is enlarged, thereby pressing the elastic force applying member in a direction in which the force pressing the first friction plate and the second friction plate against each other is released.

[0020] The electric actuator includes a shift motor and a speed reducer, and the drive cam is rotationally driven by the shift motor via the speed reducer.

[0021] An electric friction engagement device in one embodiment of the present invention has the function of detecting a piston contact point at which the elastic force applying member begins to be pressed in a direction to release the force pressing the first friction plate and the second friction plate against each other when the output torque or current value of the shift motor begins to increase at an increasing rate greater than a first threshold value when the drive cam is rotationally driven by the shift motor via the reducer in order to switch the friction engagement portion from a state in which torque is transmitted between the first component and the second component to a state in which torque is not transmitted between the first component and the second component.

[0022] Furthermore, the electric friction engagement device has a function of detecting a clutch contact point where the force pressing the first friction plate and the second friction plate against each other is zero when the drive cam is rotationally driven by the shift motor via the reducer in order to switch the friction engagement portion from a state in which torque is transmitted between the first component and the second component to a state in which torque is not transmitted between the first component and the second component. After exceeding the piston contact point, the phase related to the rotation direction of the drive cam when the increase rate becomes below a second threshold value is detected.

[0023] The electric friction engagement device according to one aspect of the present disclosure may include a function of determining whether the piston contact point or the clutch contact point is within a predetermined angle range.

[0024] An electric friction engagement device of one embodiment of the present invention can have the following function: determining whether the maximum value of the output torque or current value of the shift motor when the drive cam is rotationally driven by the shift motor via the reducer in order to switch the friction engagement portion from a state of transmitting torque between the first component and the second component to a state of not transmitting torque between the first component and the second component converges within a specified range.

[0025] In the electric friction engagement device according to one aspect of the present disclosure, the elastic urging member may include: a piston supported so as to be axially displaceable relative to the first member; and an elastic member provided between the first member and the piston.

[0026] A contact point detection method for an electric friction engagement device in one embodiment of the present invention comprises: when the drive cam is rotationally driven by the shift motor via the reducer in order to switch the friction engagement portion from a state in which torque is transmitted between the first component and the second component to a state in which torque is not transmitted between the first component and the second component, a phase related to the rotation direction of the drive cam when the output torque or current value of the shift motor begins to increase at an increase rate greater than a first threshold value is detected as a piston contact point at which the elastic force applying member begins to be pressed in a direction to release the force pressing the first friction plate and the second friction plate against each other.

[0027] Furthermore, the detection method comprises: in order to switch the friction engagement portion from a state of transmitting torque between the first component and the second component to a state of not transmitting torque between the first component and the second component, when the drive cam is rotationally driven by the shift motor via the reducer, after exceeding the piston contact point, a phase related to the rotation direction of the drive cam when the increase rate becomes below a second threshold value is detected as a clutch contact point where the force pressing the first friction plate and the second friction plate against each other is zero.

[0028] A method for detecting abnormality in an electric friction engagement device according to one embodiment of the present disclosure includes:

[0029] A step of executing the contact point detection method of the electric friction engagement device; and

[0030] and determining whether the piston contact point or the clutch contact point is greater than a predetermined angle.

[0031] A method for detecting abnormality in an electric friction engagement device according to one embodiment of the present disclosure may include the following steps:

[0032] To determine whether a maximum value of an output torque or a current value of the shift motor when the drive cam is rotationally driven by the shift motor via the reducer is within a prescribed range in order to switch the friction engagement portion from a state in which torque is transmitted between the first component and the second component to a state in which torque is not transmitted between the first component and the second component.

[0033] Effects of the Invention

[0034] According to an electric friction engagement device and an abnormality detection method thereof according to one embodiment of the present disclosure, it is possible to detect a piston contact point and a clutch contact point with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a cross-sectional view schematically showing a drive system in which a two-speed transmission including an electric friction engagement device according to an example of an embodiment of the present disclosure is assembled.

[0036] Figure 2 middle, Figure 2 (a) is a diagram showing a torque transmission path at a low reduction ratio of the two-speed transmission of this example, Figure 2 (b) is a diagram showing a torque transmission path in the high reduction ratio mode of the two-speed transmission of this example.

[0037] Figure 3 It is a perspective view of the two-speed transmission of this example.

[0038] Figure 4 It is a cross-sectional view of the two-speed transmission of this example.

[0039] Figure 5 This is a perspective view showing a two-speed transmission of this example with the planetary gear mechanism removed.

[0040] Figure 6 This is a cross-sectional view showing a two-speed transmission of this example with the planetary gear mechanism removed.

[0041] Figure 7 It is an exploded perspective view of the two-speed transmission of this example.

[0042] Figure 8 This is an exploded perspective view showing a worm gear and two support bearings removed from the electric friction engagement device of this example.

[0043] Fig. 9 This is an exploded perspective view showing a first friction plate and a second friction plate removed from the electric friction engagement device of this example.

[0044] Fig.10 yes Figure 4 Magnified view of the X section.

[0045] Fig.11 This is a perspective view showing a driving cam removed from the electric friction engagement device of this example.

[0046] Fig.12 This is an exploded perspective view showing a driven cam and rolling elements removed from the electric friction engagement device of this example.

[0047] Fig.13 middle, Fig.13(a) is a perspective view showing a flange portion and a pressing member of a rotating member removed from the two-speed transmission of this example, Fig.13 (b) is an exploded perspective view showing the flange portion of the rotating member and the pressing member removed.

[0048] Fig.14 middle, Fig.14 (a) and Fig.14 (b) is a graph showing the relationship between the rotation angle of the drive cam and the output torque and current value of the shift motor when the electric friction engagement device of this example is switched from the connection mode to the disconnection mode. Fig.14 (a) is a diagram showing the first friction plate and the second friction plate when they are new and not worn. Fig.14 (b) is a diagram showing a case where the wear of the first friction plate and the second friction plate has significantly progressed.

[0049] Fig.15 It is a cross-sectional view showing a state in which the electric friction engagement device of this example is switched to the connection mode.

[0050] Fig.16 This is a cross-sectional view showing a state in which the pressing member and the piston are in contact with each other during the switching of the electric friction engagement device of this example from the connection mode to the disconnection mode.

[0051] Fig.17 It is a cross-sectional view showing a state in which the electric friction engagement device of this example is switched to the cut-off mode.

[0052] Fig.18 It is a flowchart showing the characteristic operation of the electric friction engagement device of this example. DETAILED DESCRIPTION

[0053] Regarding the electric friction engagement device 7 according to an example of the embodiment of the present disclosure, based on an example in which the electric friction engagement device 7 is assembled in a two-speed transmission 1 for an automobile, refer to Figures 1 to 18 The two-speed transmission 1 is disposed between a drive source 2 such as an electric motor or an engine and a differential device 3 , and increases the output torque of the drive source 2 , that is, reduces the rotation, or transmits the output torque to the differential device 3 without increasing the output torque.

[0054] exist Figure 1-2 In (b), in order to facilitate understanding of the present disclosure, the elements constituting the drive source 2, the differential device 3, and the two-speed transmission 1 are schematically shown.

[0055] The two-speed transmission 1 of this example includes an input member 4 that can be rotationally driven by a driving source 2 , an output member 5 that is torque-transmittably connected to the differential device 3 , and an electric friction engagement device 7 .

[0056] The electric friction engagement device 7 includes a first member, a second member formed by the input member 4 or connected in a manner capable of transmitting torque from the input member 4, a friction engagement portion 26, an elastic urging member 27, a cam device 28, and an electric actuator 29. In this example, the first member is formed by the rotating member 6. In addition, the second member is formed by the input member 4.

[0057] The input member 4 corresponding to the second member is coaxial with the rotating member 6 which is the first member, and is relatively rotatable with respect to the rotating member 6 which is the first member.

[0058] More specifically, the input member 4 is composed of a housing or the like that houses the two-speed transmission 1, and is rotatably supported by a rolling bearing or the like (not shown) relative to a fixed portion 10 that does not rotate during use. In this example, the input member 4 is configured to be cylindrical (hollow). In addition, the input member 4 is axially disposed on one side ( Figure 1 The input member 4 has an input gear 13 meshing with a drive gear 12 provided on an output shaft 11 of the drive source 2 at its end portion (on the right side). That is, the input member 4 can be rotationally driven by the drive source 2.

[0059] In this example, the output member 5 is supported on the radially inner side of the input member 4 so as to be relatively rotatable relative to the input member 4. In addition, the output member 5 has an output gear 14 at one end portion in the axial direction. The output gear 14 meshes with a gear provided in the input portion of the differential device 3. That is, the output member 5 is connected to the input portion of the differential device 3 in a torque-transmittable manner.

[0060] In this example, the rotating member 6 corresponding to the first member is coaxial with the input member 4 and the output member 5 and is supported so as to be rotatable relative to the input member 4 and the output member 5. More specifically, the rotating member 6 is supported so as to be rotatable relative to the fixed portion 10 via the brake device 8, the cam device 28, and the radial bearing 38 for supporting the driving cam 34 constituting the cam device 28 so as to be rotatable relative to the rotating member 6.

[0061] In this example, the rotating member 6 has a small-diameter flange portion 15 protruding radially outward in the axial middle portion, and a flange portion 15 located on the other axial side ( Figure 1 The portion (on the left side) has a flange portion 16 protruding radially outward.

[0062] The flange portion 16 includes: a first circular wheel portion 18 in the shape of a hollow circular plate; a first cylindrical portion 19 bent from the radially outer end of the first circular wheel portion 18 toward the other axial side; a second circular wheel portion 20 in the shape of a hollow circular plate bent from the radially outer end of the first cylindrical portion 19 toward the radially outer side; and a second cylindrical portion 21 bent from the radially outer end of the second circular wheel portion 20 toward the other axial side. The first circular wheel portion 18 has partially arc-shaped through holes 17 at multiple locations in the radially intermediate portion for inserting the partial cylindrical portion 63 of the pressing member 58 constituting the electric friction engagement device 7.

[0063] In this example, the rotating member 6 is fixed by externally fitting on the shaft member 22 having the small-diameter flange portion 15. Fig.13 (b) is constituted by the stepped cylindrical component 23 shown on the left side of FIG. That is, the stepped cylindrical component 23 has a first annular portion 18, a first cylindrical portion 19, a second annular portion 20, a second cylindrical portion 21, and a small-diameter cylindrical portion 24 bent from the radially inner end of the first annular portion 18 toward the other axial side. The stepped cylindrical component 23 of the rotating component 6 is supported and fixed by spline engagement of the inner spline portion 25 provided on the inner circumference of the small-diameter cylindrical portion 24 with the outer spline portion provided on the outer circumference of the shaft component 22. However, the rotating component can also be constituted by combining and fixing the stepped cylindrical component and the shaft component by press-fitting, welding, etc.

[0064] In this example, the electric friction engagement device 7 is provided between the input member 4 and the rotating member 6 , and switches between a connection mode in which torque is transmitted between the input member 4 and the rotating member 6 and a disconnection mode in which torque is not transmitted.

[0065] The friction engagement portion 26 constituting the electric friction engagement device 7 includes at least one first friction plate 30 and at least one second friction plate 31 supported so as to be relatively displaceable in the axial direction, and is provided between the first member (rotating member 6) and the second member (input member 4).

[0066] The friction engagement portion 26 switches to a state where torque is transmitted between the first member (rotating member 6) and the second member (input member 4), that is, a state where the first member (rotating member 6) and the second member (input member 4) rotate integrally by pressing the first friction plate 30 and the second friction plate 31 against each other. On the other hand, the friction engagement portion 26 switches to a state where torque is not transmitted between the first member (rotating member 6) and the second member (input member 4), that is, a state where the first member (rotating member 6) and the second member (input member 4) rotate relatively, by releasing the force pressing the first friction plate 30 and the second friction plate 31 against each other.

[0067] In this example, the friction engagement portion 26 is formed by a multi-plate clutch in which a plurality of first friction plates 30 supported by the rotating member 6 and a plurality of second friction plates 31 supported by the input member 4 are alternately stacked.

[0068] The plurality of first friction plates 30 are supported on the outer peripheral surface of the first cylindrical portion 19 so as to be displaceable in the axial direction.

[0069] The plurality of second friction plates 31 are supported on the inner peripheral surface of the end portion on the other axial side of the input member 4 so as to be displaceable in the axial direction.

[0070] The elastic urging member 27 is provided between the first member (rotating member 6 ) and the friction engagement portion 26 , and elastically urges the first friction plate 30 and the second friction plate 31 in a direction of pressing each other. In this example, the elastic urging member 27 includes a piston 32 and an elastic member 33 .

[0071] The piston 32 is supported so as to be axially displaceable relative to the rotating member 6. In this example, the piston 32 is configured in a hollow circular plate shape and is supported around a portion of the rotating member 6 that is axially located between the small-diameter flange portion 15 and the flange portion 16 so as to be axially displaceable relative to the rotating member 6. The piston 32 makes the end surface on the other axial side of the radially outer portion face the axial side surface of the first friction plate 30 that is located most axially on one side of the first friction plate 30.

[0072] The elastic member 33 is provided between the rotating member 6 and the piston 32. In this example, the elastic member 33 is clamped in an elastically compressed state between the other axial side surface of the small-diameter flange portion 15 of the rotating member 6 and one axial side surface of the piston 32. That is, the elastic urging member 27 presses the first friction plate 30 on the most axial side toward the other axial side via the piston 32 by the elastic restoring force of the elastic member 33, thereby elastically urging the first friction plate 30 and the second friction plate 31 in the direction of pressing each other.

[0073] In this example, the elastic component 33 is composed of at least one (two in this example) disc spring. However, in the case of implementing the present disclosure, the specific structure of the elastic component is not particularly limited. For example, the elastic component can also be composed of at least one coil spring.

[0074] The cam device 28 includes a driving cam 34, a driven cam 35, and a plurality of rolling elements 36. The cam device 28 moves the driven cam 35 in a direction to increase the axial distance between the driven cam 35 and the driving cam 34 as the driving cam 34 rotates, thereby pressing the elastic urging member 27 in a direction to release the force pressing the first friction plate 30 and the second friction plate 31 against each other.

[0075] The driving cam 34 is supported relative to the rotating member 6 so as to be rotatable relative to the rotating member 6 and the input member 4 and not to be axially displaceable relative to the rotating member 6. Figure 4 As shown in FIGS. 1 and 1B , the driving cam 34 is supported by the rotating member 6 via a cylindrical member 37 , a radial bearing 38 , and an angular contact ball bearing 39 so as to be relatively rotatable with respect to the rotating member 6 .

[0076] The tubular member 37 includes a cylindrical portion 40 and an outward flange portion 41 bent radially outward from the other axial end of the cylindrical portion 40. The tubular member 37 is supported and fixed to the fixing portion 10 by screwing or the like.

[0077] The radial bearing 38 includes an inner ring 42 which is externally fitted and fixed to the end portion on the other axial side of the rotating member 6; an outer ring 43 which is internally fitted and fixed to the cylindrical portion 40 of the tubular member 37; and a plurality of rolling elements 44 which are freely arranged between the inner ring 42 and the outer ring 43. In the example shown in the figure, the radial bearing 38 is composed of a multi-row deep groove ball bearing using balls as the rolling elements 44. However, the radial bearing is not particularly limited as long as it can perform relative rotation between the first member and the cam device and can support the axial force generated by the elastic urging member. For example, it can also be composed of a deep groove ball bearing, a radial angular contact ball bearing, a radial tapered roller bearing, etc.

[0078] The angular contact ball bearing 39 includes an inner ring 45 fitted and fixed to the cylindrical portion 40 of the tubular member 37 , an outer ring 46 fitted and fixed to the drive cam 34 , and a plurality of balls 47 rotatably arranged between the inner ring 45 and the outer ring 46 .

[0079] The driven cam 35 is supported so as to be relatively rotatable and axially displaceable relative to the driving cam 34. More specifically, the driven cam 35 is arranged around the rotating member 6 in a manner that it can only be displaced in the axial direction. In this example, the driven cam 35 has a hollow circular plate shape and is supported so as to be axially displaceable relative to the fixed portion 10. In this example, the driven cam 35 is supported so as to be axially displaceable relative to the fixed portion 10 by spline engagement of an inner spline portion 51 provided on the inner circumferential surface of the driven cam 35 with an outer spline portion 52 provided on the outer circumferential surface of the axially one side portion of the cylindrical portion 40 of the tubular member 37.

[0080] However, the method of supporting the driven cam on the fixed part is not particularly limited as long as the driven cam can be supported so as to be axially displaceable relative to the fixed part. For example, the driven cam can be supported so as to be axially displaceable relative to the fixed part by engaging a convex portion of one of the driven cam and the fixed part with a concave groove key of the other.

[0081] In this example, if Fig.12 As shown, the driven cam 35 has rectangular holes 53 penetrating in the axial direction at multiple locations (three locations in the example shown) in the circumferential direction of the radial middle portion, and has substantially semicircular plate-shaped support plate portions 54a and 54b protruding toward one axial side from both radial sides of the rectangular holes 53. The radially outer support plate portion 54a of the support plate portions 54a and 54b has a circular hole penetrating in the radial direction, i.e., a support hole 55, and the radially inner support plate portion 54b has a support recess 56 having a circular opening on the radially outer side surface.

[0082] The driven cam 35 faces the piston 32 of the elastic urging member 27 via a thrust bearing 57 and a pressing member 58 .

[0083] The thrust bearing 57 is provided between the pressing member 58 and the driven cam 35. The thrust bearing 57 includes a pair of track wheels 59a, 59b and a plurality of rolling elements 60 arranged to roll freely between the pair of track wheels 59a, 59b. The track wheel 59b on the other axial side of the pair of track wheels 59a, 59b is supported and fixed to the driven cam 35.

[0084] The pressing member 58 includes a cylindrical base 62 and a partially cylindrical portion 63 protruding toward one axial side from a plurality of locations (three locations in the illustrated example) in the circumferential direction of an end portion on one axial side of the base 62. The axially one side track wheel 59a of a pair of track wheels 59a and 59b of the thrust bearing 57 is supported and fixed at the end portion on the other axial side of the base 62. The partially cylindrical portion 63 is inserted through the through hole 17 of the rotating member 6, and the front end portion (the axially one side end portion) of the partially cylindrical portion 63 is opposed to the radially intermediate portion of the axially other side surface of the piston 32.

[0085] In this example, a preload applying unit 61 for applying preload to the thrust bearing 57 is provided between the pressing member 58 and the rotating member 6. The preload applying unit 61 is clamped in an elastically compressed state between the pressing member 58 and the other axial side surface of the first circular wheel portion 18 constituting the flange portion 16 of the rotating member 6. Figure 2 As shown in FIG. 5( b ), even when the piston 32 is pressed toward one side in the axial direction against the elastic restoring force of the elastic member 33 , preload is applied to the thrust bearing 57 , and the thrust bearing 57 is prevented from falling out from between the elastic urging member 27 and the cam device 28 .

[0086] In addition, the elastic force of the preload applying unit 61 is smaller than the elastic restoring force of the elastic member 33. The preload applying unit 61 can be composed of, for example, at least one disc spring or at least one coil spring. In this example, the preload applying unit 61 is composed of one coil spring.

[0087] In this example, the cam device 28 includes a plurality of (three in this example) rolling elements 36 and a driving cam surface 48 included in the driving cam 34 as means for relatively displacing the driving cam 34 and the driven cam 35 .

[0088] like Fig.11 As shown in the figure, the driving cam surface 48 is formed by alternately arranging the same number of concave portions and convex portions in the circumferential direction on the radial inner portion of the axial side surface of the driving cam 34. The driving cam 34 has helical gears, i.e., gear teeth 49, on the outer circumferential surface. Furthermore, the driving cam 34 has pin portions 50 protruding toward one side in the axial direction at multiple locations (three locations in the example shown) in the circumferential direction of the radial middle portion of the axial side surface.

[0089] The rolling elements 36 are each composed of a cylindrical roller, and are supported to freely rotate relative to the support plate portions 54a and 54b via a cylindrical support shaft 64 and a plurality of rollers 65. That is, the end portion of the support shaft 64 on the outer side in the radial direction with the central axis of the driven cam 35 as the center is embedded and fixed in the support hole 55 of the support plate portion 54a on the outer side in the radial direction, and the end portion of the support shaft 64 on the inner side in the radial direction with the central axis of the driven cam 35 as the center is embedded and fixed in the support recess 56 of the support plate portion 54b on the inner side in the radial direction.

[0090] The plurality of rollers 65 are rotatably sandwiched between the inner circumference of the rolling element 36 and the outer circumference of the axially intermediate portion of the support shaft 64. Thus, the rolling element 36 is rotatably supported by the driven cam 35 about the rotation axis C extending in radial directions about the central axis of the driven cam 35.

[0091] With the rolling element 36 supported by the driven cam 35, the other axial side portion of the rolling element 36 is disposed inside the rectangular hole 53. The rolling element 36 has its outer peripheral surface in rolling contact with the driving cam surface 48 provided on the other axial side surface of the driving cam 34.

[0092] In the cam device 28 , as the driving cam 34 rotates, the amount of lift of the rolling element 36 from the bottom of the recessed portion constituting the driving cam surface 48 increases or decreases, whereby the driven cam 35 moves in the axial direction.

[0093] That is, when the driving cam 34 is rotated in a predetermined direction, the amount of rise of the rolling element 36 from the bottom of the recessed portion constituting the driving cam surface 48 increases, and the driven cam 35 moves axially to one side. When the driven cam 35 moves axially to one side, the piston 32 of the elastic urging member 27 is pressed axially to one side via the thrust bearing 57 and the pressing member 58, and the elastic member 33 is elastically compressed.

[0094] As a result, the force pressing the first friction plate 30 and the second friction plate 31 against each other is reduced and eventually lost. Furthermore, the return spring 78 increases the distance between the first friction plate 30 and the second friction plate 31, so that the friction engagement portion 26 switches to a state where no torque is transmitted between the rotating member 6 and the input member 4.

[0095] On the other hand, when the driving cam 34 is rotated in the direction opposite to the predetermined direction, the amount of the rolling element 36 rising from the bottom of the concave portion constituting the driving cam surface 48 is reduced, and the driven cam 35 moves to the other axial side. When the driven cam 35 moves to the other axial side, the force pressing the piston 32 of the elastic urging member 27 toward one axial side via the thrust bearing 57 and the pressing member 58 is reduced.

[0096] If the force pressing the piston 32 toward one axial side is reduced, the piston 32, the thrust bearing 57, and the pressing member 58 are pressed toward the other axial side mainly by the elastic restoring force of the first friction plate 30 and the elastic member 33, and the second friction plate 31 closest to the axial side is pressed toward the other axial side by the piston 32. As a result, the first friction plate 30 and the second friction plate 31 are pressed against each other, and the friction engagement portion 26 is switched to a state of transmitting torque between the rotating member 6 and the input member 4.

[0097] In this example, a roller is used as the rolling element 36, and the rolling element 36 is supported so as to freely rotate (rotate) about the rotation axis C in the radial direction centered on the central axis of the driven cam 35 relative to the driven cam 35. Therefore, by rotating the driving cam 34, the driven cam 35 can be reliably displaced in the axial direction.

[0098] When balls are used as rolling elements constituting the cam device, when the driving cam is rotated, sliding may occur at the rolling contact portion between the surface of the rolling element and the driving cam surface and / or the driven cam surface. When sliding occurs at the rolling contact portion between the surface of the rolling element and the driving cam surface and / or the driven cam surface, the driven cam may not be displaced in the axial direction, or the axial displacement amount of the driven cam relative to the rotation amount of the driving cam may not be sufficiently ensured.

[0099] In this example, since rollers are used as rolling elements 36, when the driving cam 34 is rotated, it is possible to prevent the outer peripheral surface of the rolling element 36 from sliding in the rolling contact portion with the driving cam surface 48, and the driving cam 34 is rotated, thereby reliably displacing the driven cam 35 in the axial direction. However, when implementing the present disclosure, balls can also be used as rolling elements constituting the cam device.

[0100] In addition, when implementing the present disclosure, the cam device can also be applied to a cam device that directly engages (slides) a driving cam surface of a driving cam with a driven cam surface of a driven cam, or a cam device having a driven cam and a driving cam, wherein the driven cam has a guide groove extending in the circumferential direction and changing in the axial direction on the outer peripheral surface, and the driving cam has an engaging protrusion that can engage displaceably along the guide groove.

[0101] The electric actuator 29 includes a shift motor 66 and a speed reducer 67 , and the drive cam 34 of the cam device 28 is rotationally driven by the shift motor 66 via the speed reducer 67 .

[0102] In this example, the speed reducer 67 is composed of a worm speed reducer. That is, the speed reducer 67 is formed by meshing the worm teeth provided on the outer peripheral surface of the worm 68 connected to the output shaft of the shift motor 66 with the gear teeth 49 provided on the outer peripheral surface of the drive cam 34. The worm 68 is supported by a pair of support bearings 69a and 69b so as to be rotatable relative to the fixed part 10.

[0103] However, the speed reducer 67 may be configured by meshing a spur gear or bevel gear provided on the output shaft of the electric motor with a spur gear or bevel gear provided on the drive cam, or by providing a belt or chain between the output shaft of the electric motor and the drive cam.

[0104] In this example, a return spring 78 (only in the case of the first friction plate 30 and the second friction plate 31) is further provided between the first friction plate 30 and the second friction plate 31 to elastically bias the first friction plate 30 and the second friction plate 31 in a direction to expand the distance between the first friction plate 30 and the second friction plate 31. Figure 1 In addition, the elastic force of the return spring 78 is smaller than the elastic restoring force of the elastic member 33 of the elastic force applying member 27.

[0105] In particular, the electric friction engagement device 7 of this example has a piston contact point θ at which the tightening force of the friction engagement portion 26 begins to decrease when switching from a state in which torque is transmitted between the first member, the rotating member 6, and the second member, the input member 4 (connection mode) to a state in which torque is not transmitted between the rotating member 6 and the input member 4 (disconnection mode). p and detecting the clutch contact point θ where the clamping force is 0 f Furthermore, the electric friction engagement device 7 of this example has a function for detecting an abnormality that may cause a malfunction.

[0106] Regarding the electric friction engagement device 7 of this example, after the additional components have been described, the above-described functions will be further described.

[0107] The brake device 8 is provided between the fixed portion 10 and the rotating member 6 to switch the rotating member 6 between a state in which it can rotate relative to the fixed portion 10 and a state in which it cannot rotate. In this example, the brake device 8 is provided between the inner circumference of the fixed portion 10 and the second cylindrical portion 21 of the rotating member 6.

[0108] The brake device 8 can be composed of a meshing type or friction type brake device that can be switched between on and off by an actuator. The actuator for switching between the on and off states of the brake device is not particularly limited, and a hydraulic actuator, an electromagnetic actuator, etc. can be used.

[0109] In this example, the brake device 8 includes an outer diameter side cylindrical member 70 , an inner diameter side cylindrical member 71 , at least one engaging pin (not shown), and a selector plate 72 .

[0110] The outer diameter side cylindrical member 70 has an outer circumferential side concavoconvex portion 73 formed by alternately arranging concavoconvex portions and convex portions in the circumferential direction on the outer circumferential surface. The outer diameter side cylindrical member 70 is supported by the fixing part 10 in a relatively non-rotatable manner by engaging the outer circumferential side concavoconvex portion 73 with the inner circumferential side concavoconvex portion provided on the inner circumferential surface of the fixing part 10.

[0111] The inner diameter side cylindrical member 71 is externally fitted and fixed to the second cylindrical portion 21 of the rotating member 6 in a relatively non-rotatable manner.

[0112] The engaging pin is arranged between the outer diameter side cylindrical member 70 and the inner diameter side cylindrical member 71 in a manner that allows engagement and disengagement. In this example, the engaging pin is supported by the outer diameter side cylindrical member 70 in a state where it protrudes radially inward from the inner circumferential surface of the outer diameter side cylindrical member 70 and is elastically forced radially inward. The inner diameter side cylindrical member 71 has an engaging recessed portion on the outer circumferential surface that can engage with the front end portion of the engaging pin.

[0113] The selection plate 72 has a circumferential concave-convex portion, i.e., a mode selection portion, and has engagement holes (not shown) at multiple locations (three locations in this example) in the circumferential direction of the other axial side surface. The pin portion 50 provided by the drive cam 34 is embedded in each engagement hole without play. As a result, the drive cam 34 and the selection plate 72 rotate integrally (in the same direction and at the same speed).

[0114] The brake device 8 switches between a state in which the outer diameter side cylindrical component 70 and the inner diameter side cylindrical component 71 can rotate relative to each other and a state in which they cannot rotate relative to each other based on the rotation of the selection plate 72. That is, the selection plate 72 is rotated, and the convex portion constituting the mode selection portion pushes the engagement pin toward the radial outside, thereby releasing the engagement between the engagement pin and the engagement recess. As a result, the rotation of the inner diameter side cylindrical component 71 relative to the outer diameter side cylindrical component 70 is allowed, and the rotation of the rotating component 6 relative to the fixed portion 10 is allowed.

[0115] On the other hand, the selection plate 72 is rotated, so that the convex portion constituting the mode selection portion moves to a position circumferentially disengaged from the front end portion of the engagement pin, so that the engagement pin engages with the engagement recess. Thus, the inner diameter side cylindrical member 71 is prevented from rotating relative to the outer diameter side cylindrical member 70, and the rotation of the rotating member 6 relative to the fixed portion 10 is prevented.

[0116] When implementing the present disclosure, the brake device is not limited to the brake device that can switch the on / off state by the actuator, and various conventionally known clutches can be used. Specifically, the brake device can also be composed of a one-way clutch including a free wheel.

[0117] In this example, the planetary reduction mechanism 9 includes a sun gear 74, a ring gear 75, a carrier 76, and a plurality of planetary gears 77. That is, the planetary reduction mechanism 9 is composed of a single pinion type planetary gear mechanism.

[0118] The sun gear 74 is connected to the rotating member 6 in a torque-transmittable manner. In this example, the sun gear 74 is provided at an end portion of the rotating member 6 on one side in the axial direction.

[0119] The ring gear 75 is coaxially disposed around the sun gear 74 and is connected to the input member 4 in a torque-transmittable manner. In this example, the ring gear 75 is provided at an axially intermediate portion of the input member 4.

[0120] The planet carrier 76 is disposed coaxially with the sun gear 74 and the ring gear 75 in the radial direction, between the sun gear 74 and the ring gear 75 , and is connected to the output member 5 in a torque-transmittable manner.

[0121] The plurality of planetary gears 77 mesh with the sun gear 74 and the ring gear 75 , respectively, and are supported by the planetary carrier 76 so as to be rotatable (rotatable) about their own central axes.

[0122] In the case of implementing the present disclosure, a double pinion type planetary gear mechanism can also be used as a planetary reduction mechanism. Alternatively, the planetary reduction mechanism can also be composed of a friction roller mechanism, which has: a sun roller; an annular roller, which is arranged around the sun roller; and a planetary roller, which is arranged between the sun roller and the annular roller in the radial direction, and makes the outer peripheral surface, i.e., the rolling surface, frictionally engage with the outer peripheral surface of the sun roller and the inner peripheral surface of the annular roller.

[0123] The two-speed transmission 1 of this example can switch between a low reduction ratio mode in which the reduction ratio between the input component 4 and the output component 5 is small (the reduction ratio is 1) and a high reduction ratio mode in which the reduction ratio is larger than the low reduction ratio mode by switching the mode of the electric friction engagement device 7 and the on / off state of the brake device 8.

[0124] <Low reduction ratio mode>

[0125] In order to switch the two-speed transmission 1 to the low speed reduction ratio mode, the electric friction engagement device 7 is switched to the connection mode, and the brake device 8 is disconnected.

[0126] Specifically, if Figure 2 As shown in FIG. 2( a), the driving cam 34 is rotationally driven by the shift motor 66 in the direction opposite to the predetermined direction, that is, in the direction in which the amount of rise of the rolling element 36 from the bottom of the concave portion constituting the driving cam surface 48 decreases. As a result, the driven cam 35 releases the force pressing the piston 32 toward one side in the axial direction via the thrust bearing 57 and the pressing member 58.

[0127] If the force pressing the piston 32 toward one axial side is released, the piston 32, the thrust bearing 57, and the pressing member 58 are pressed toward the other axial side mainly by the elastic restoring force of the first friction plate 30 and the elastic member 33, and the second friction plate 31 closest to the axial side is pressed toward the other axial side by the piston 32. As a result, the first friction plate 30 and the second friction plate 31 are pressed against each other, and the input member 4 rotates integrally with the rotating member 6. That is, the electric friction engagement device 7 is switched to the connection mode. As a result, the sun gear 74 and the ring gear 75 rotate integrally.

[0128] When the drive cam 34 is driven to rotate in the direction opposite to the prescribed direction, the selection plate 72 is also driven to rotate in the direction opposite to the prescribed direction. As the selection plate 72 rotates, the engagement pin supported by the outer diameter side cylindrical member 70 is pushed up radially outward by the convex portion constituting the mode selection portion of the selection plate 72, and the engagement between the engagement pin and the engagement recess of the inner diameter side cylindrical member 71 is released.

[0129] Thus, the brake device 8 is disengaged. That is, the rotation of the inner diameter side cylindrical member 71 relative to the outer diameter side cylindrical member 70 is permitted, and the rotation of the rotating member 6 relative to the fixed portion 10 is permitted. As a result, the rotation of the sun gear 74 relative to the fixed portion 10 is permitted.

[0130] In the low reduction ratio mode, the sun gear 74, the ring gear 75 and the planetary carrier 76 rotate in the same direction and at the same speed, and the planetary reduction mechanism 9 rotates as a whole in a so-called sticking state. Figure 2 The path shown by the bold line in (a) is not increased (reduced) but directly transmitted to the output member 5. In other words, in the low reduction ratio mode, the reduction ratio between the input member 4 and the output member 5 is 1.

[0131] <High reduction ratio mode>

[0132] In order to switch the two-speed transmission 1 to the high reduction ratio mode, the electric friction engagement device 7 is switched to the disconnection mode and the brake device 8 is connected.

[0133] Specifically, if Figure 2 As shown in (b), the driving cam 34 is driven to rotate by the shift motor 66 in the predetermined direction, that is, the direction in which the amount of the rolling element 36 rising from the bottom of the concave portion constituting the driving cam surface 48 increases. As a result, the driven cam 35 presses the piston 32 toward one side in the axial direction via the thrust bearing 57 and the pressing member 58, elastically reducing the axial dimension of the elastic member 33, and releasing the force pressing the first friction plate 30 and the second friction plate 31 against each other.

[0134] As a result, the return spring 78 acts to expand the gap between the first friction plate 30 and the second friction plate 31, and the input member 4 and the rotating member 6 rotate relative to each other. That is, the electric friction engagement device 7 is switched to the disconnection mode. As a result, the sun gear 74 and the ring gear 75 can rotate relative to each other.

[0135] When the driving cam 34 is driven to rotate in the prescribed direction, the selection plate 72 is also driven to rotate in the prescribed direction. As the selection plate 72 rotates, the convex portion constituting the mode selection portion of the selection plate 72 moves to a position where it is disengaged from the front end portion of the engagement pin supported by the outer diameter side cylindrical member 70 in the circumferential direction. As a result, the engagement pin engages with the engagement recess of the inner diameter side cylindrical member 71, and the brake device 8 is connected. That is, the relative rotation of the rotating member 6 with respect to the fixed portion 10 is prevented, and the rotation of the sun gear 74 with respect to the fixed portion 10 is prevented.

[0136] In the high reduction ratio mode, the rotation torque of the input member 4 is Figure 2 The path shown by the bold line in (b) is the sequential transmission of the input member 4, the ring gear 75, the rotational motion of the planetary gear 77, the revolution motion of the planetary gear 77 due to meshing with the sun gear 74, the planetary carrier 76 and the output member 5.

[0137] Thus, in the high reduction ratio mode, the rotational torque of the input member 4 is increased by the planetary reduction mechanism 9 and transmitted to the output member 5. In addition, the reduction ratio between the input member 4 and the output member 5 in the high reduction ratio mode is determined by the gear ratio between the ring gear 75 and the sun gear 74 (the number of teeth of the ring gear 75 / the number of teeth of the sun gear 74).

[0138] The two-speed transmission 1 of this example can switch the reduction ratio between the input member 4 and the output member 5 to two stages, high and low, by switching the mode of the electric friction engagement device 7 and the on / off state of the brake device 8. Specifically, in the area where the rotational torque input to the input member 4 is low speed and high torque, the two-speed transmission 1 is switched to the high reduction ratio mode, and in the area where the rotational torque input to the input member 4 is high speed and low torque, it is switched to the low reduction ratio mode. Therefore, the acceleration performance and high-speed performance of electric vehicles and hybrid vehicles when driving only with electric motors as the driving source can be made close to those of gasoline engine vehicles.

[0139] When switching the mode of the two-speed transmission 1, the switching of the mode of the electric friction engagement device 7 and the switching of the on / off state of the brake device 8 do not need to be performed completely at the same time, and can also be performed slightly before and after. That is, the tightening force and timing of the electric friction engagement device 7 and the brake device 8 can be appropriately adjusted so that the speed change shock accompanying the mode switching of the two-speed transmission 1 can be reduced.

[0140] The electric friction engagement device 7 of this example includes a piston contact point θ for detecting the start of a decrease in the tightening force of the friction engagement portion 26 when switching from the connection mode to the disconnection mode. p The function and detection of the clutch contact point θ where the clamping force is 0 f The following uses Fig.14 (a)~ Fig.18 These functions are described.

[0141] Fig.14 (a) and Fig.14 (b) is a graph showing the relationship between the rotation angle θ of the drive cam 34 and the output torque T and the current value A of the shift motor 66 when the electric friction engagement device 7 is switched from the connection mode to the disconnection mode. Fig.14 (a) shows the first friction plate 30 and the second friction plate 31 when they are new and unworn. Fig.14 (b) shows a case where the wear of the first friction plate 30 and the second friction plate 31 has significantly progressed.

[0142] according to Fig.14 (a) and Fig.14 (b) It can be seen that when the mode of the electric friction engagement device 7 is switched, the output torque T of the shift motor 66 and the current value A of the shift motor 66 change in the same trend. In the electric friction engagement device 7 of this example, the piston contact point θ is detected based on the current value A of the shift motor 66 when the electric friction engagement device 7 is switched from the connection mode to the disconnection mode. p and the clutch contact point θ f .

[0143] When the electric friction engagement device 7 is switched to the connection mode, the rolling element 36 of the cam device 28 is located at the bottom of the concave portion constituting the driving cam surface 48. Fig.15 As shown in FIG. 1 , there is a piston gap C between the end of one axial side of the pressing member 58 and the other axial side of the piston 32. p Based on this piston clearance C p The presence of allows the piston 32 to be displaced to the other side in the axial direction.

[0144] Therefore, the piston 32 is elastically pressed toward the other axial side by the elastic restoring force of the elastic member 33, and the first friction plate 30 closest to one axial side is pressed toward the other axial side by the piston 32, so that the first friction plate 30 and the second friction plate 31 are pressed against each other.

[0145] In order to switch the electric friction engagement device 7 from the connection mode to the disconnection mode, the drive cam 34 is rotated in the predetermined direction by energizing the shift motor 66, so that the amount of the rolling element 36 rising from the bottom of the recessed portion is increased. At this time, except for the starting current that temporarily flows, the current value A of the shift motor 66 is substantially constant ( Fig.14 (a) and Fig.14 (b) range α).

[0146] When the pressing member 58 is moved toward one side in the axial direction by increasing the amount of the rolling element 36 rising from the bottom of the recess, as shown in FIG. Fig.16 As shown, the end portion of the pressing member 58 on one axial side contacts the other axial side of the piston 32. In other words, the piston clearance C p is 0.

[0147] When from Fig.16 In the state shown, when the driving cam 34 is further rotationally driven in the prescribed direction by the shift motor 66, the piston 32 is pressed toward one side in the axial direction by the driven cam 35 via the pressing member 58, overcoming the elastic restoring force of the elastic member 33. In this state, a part of the elastic restoring force of the elastic member 33 is supported by the cam device 28 via the pressing member 58 and the thrust bearing 57, and the remaining part is supported by the fixed portion 10 via the friction engagement portion 26 and the brake device 8.

[0148] When the piston 32 is pressed toward one side in the axial direction, the force of the first friction plate 30 and the second friction plate 31 pressing each other gradually decreases mainly due to the elastic restoring force of the second friction plate 31 and the elastic member 33. That is, the fastening force of the friction engagement portion 26 gradually decreases.

[0149] While the tightening force of the friction engagement portion 26 is gradually reduced, the current value A of the shift motor 66 increases at a substantially constant rate of increase (slope) ( Fig.14(a) and Fig.14 That is, the increase rate of the current value A in the range β is greater than the increase rate of the current value A in the range α.

[0150] In the electric friction engagement device 7 of this example, in order to switch the electric friction engagement device 7 from the connection mode to the disconnection mode, after the shift motor 66 starts to be energized, the phase (rotation angle from the reference position (for example, the initial position where the rolling element 36 is located at the bottom of the recess)) θ related to the rotation direction of the drive cam 34 when the current value A of the shift motor 66 starts to increase at an increase rate of more than a predetermined first threshold value is detected as the piston clearance C p The piston contact point θ is 0 p The first threshold value can be obtained in advance through experiments, simulations, etc.

[0151] The increase rate of the current value A is the increase amount ΔA of the current value A per unit rotation angle Δθ of the drive cam 34. When the drive cam 34 is rotated in the predetermined direction at a constant rotation speed, the increase amount ΔA of the current value A per unit time can also be used for determination.

[0152] The tightening force of the friction engagement portion 26 gradually decreases, and when the tightening force becomes 0, from this moment on, as shown in FIG. Fig.17 As shown in FIG. 1 , a clutch clearance C begins to be generated between the end of the piston 32 on the other axial side and the first friction plate 30 located on the most axial side. f When the clutch clearance C begins to appear f When the elastic restoring force of the elastic member 33 is substantially entirely supported by the cam device 28 via the pressing member 58 and the thrust bearing 57 .

[0153] At the beginning of the clutch clearance C f After that, the current value A of the shift motor 66 increases slowly and logarithmically ( Fig.14 (a) and Fig.14 That is, the increase rate of the current value A in the range γ is smaller than the increase rate of the current value A in the range β.

[0154] In the electric friction engagement device 7 of this example, when the electric friction engagement device 7 is switched from the connection mode to the disconnection mode, when the phase related to the rotation direction of the drive cam 34 exceeds the piston contact point θ p Then, the phase θ related to the rotation direction of the drive cam 34 when the increase rate of the current value A of the shift motor 66 becomes equal to or less than a predetermined second threshold value is detected as the clutch clearance C. f The clutch contact point θ is 0 f In addition, the second threshold value is smaller than the first threshold value. The second threshold value can be obtained in advance through experiments, simulations, etc.

[0155] The electric friction engagement device 7 of this example also has a function for detecting abnormality that may lead to a malfunction.

[0156] The electric friction engagement device 7 of this example has a function of determining whether or not the wear of the first friction plates 30 and the second friction plates 31 has not progressed to the usage limit as a first function for abnormality detection.

[0157] When the wear of the first friction plate 30 and the second friction plate 31 increases with the use of the electric friction engagement device 7, the amount of pressure required by the elastic force member 27 on the other axial side of the first friction plate 30 closest to the axial side for switching the electric friction engagement device 7 to the connection mode increases. In other words, the amount of pressure required by the cam device 28 on one axial side of the piston 32 when switching the electric friction engagement device 7 to the disconnection mode decreases.

[0158] As a result, the relationship between the rotation angle θ of the drive cam 34 and the current value A of the shift motor 66 changes from Fig.14 The state change shown in (a) is Fig.14 (b) The state shown. Fig.14 (a) and Fig.14 (b) It can be seen that when the wear amount of the first friction plate 30 and the second friction plate 31 increases, the piston contact point θ p and the clutch contact point θ f Become smaller.

[0159] The piston contact point θ can be determined by p or clutch contact point θ f Whether the piston contact point θ is within the specified angle range is determined to determine whether the wear of the first friction plate 30 and the second friction plate 31 has reached the limit of use. p or clutch contact point θ f is the specified lower limit value θ min Above the upper limit value θ max The following functions.

[0160] Lower limit value θ min and the upper limit θ max The piston contact point θ can be obtained in advance by experiments or simulations. p and clutch contact point θ f Any one of the contact points is appropriately set as a judgment criterion.

[0161] In the electric friction engagement device 7 of this example, by determining the clutch contact point θ f Whether the angles are within a predetermined range is determined to determine whether the wear of the first friction plate 30 and the second friction plate 31 has progressed to the limit of use.

[0162] The electric friction engagement device 7 of this example further has a function of determining the maximum value A of the current value A of the shift motor 66. peak In other words, the electric friction engagement device 7 has a function of determining whether the maximum value A of the shift motor 66 is within a predetermined range. peak The lower limit value A min Above the upper limit value A max The following functions.

[0163] Lower limit A min And the upper limit A max In the electric friction engagement device 7 of this example, when the rolling element 36 rises to the front end of the convex portion constituting the driving cam surface 48, the current value A of the shift motor 66 reaches the maximum value A. peak .

[0164] In the electric friction engagement device 7 of this example, along Fig.18 The flowchart shown in FIG. 1 performs the detection of the piston contact point θ. p Function and detection of clutch contact point θ f functions, and functions for detecting anomalies.

[0165] First, in S1, it is determined whether the rolling element 36 of the cam device 28 is located at the initial position, that is, at the bottom of the concave portion constituting the driving cam surface 48. This determination can be performed by any method. For example, it can be performed based on the output value of a position sensor that detects the axial position of the driven cam 35 or the pressing member 58, or based on the number of rotation pulses generated by a Hall element or the like provided on the shift motor 66.

[0166] If it is determined in S1 that the rolling element 36 is not located at the initial position, the process proceeds to S1 - 1 , and the drive cam 34 is rotationally driven by the shift motor 66 to move the rolling element 36 to the initial position, and then the process returns to S1 .

[0167] If it is determined in S1 that the rolling element 36 is located at the initial position, the process proceeds to S2, and the drive cam 34 is started to be driven to rotate in the predetermined direction by energizing the shift motor 66. The rotation speed of the drive cam 34 can be set to any speed.

[0168] In S3, the current value A of the shift motor 66 is monitored, and the rotation angle θ of the drive cam 34 from the initial position when the increase rate of the current value A becomes equal to or greater than the first threshold value is detected as the piston contact point θ. p .

[0169] In S4, the current value A of the shift motor 66 is monitored, and the rotation angle θ of the drive cam 34 from the initial position when the increase rate of the current value A becomes less than the second threshold value is detected as the clutch contact point θ. f .

[0170] In S5, the clutch contact point θ is determined. f Whether it is within the specified angle range, that is, whether it is within the specified lower limit value θ min Above the upper limit value θ max Next, when the clutch contact point θ is determined f The angle does not converge within the specified range, i.e., is less than the specified lower limit value θ min or greater than the specified upper limit θ max In the case of , enter S5-1 and determine the clutch contact point θ f Whether the number of abnormal detections i reaches the preset number of times n.

[0171] The clutch contact point θ is determined to be f When the number of abnormality detections i does not reach the specified number of times n, that is, is less than n, in S5-2, 1 is added to i and the process returns to S1.

[0172] In S5-1, it is determined that the clutch contact point θ f When the number of abnormal detections k reaches the preset number of times n, the process proceeds to S5-3, the alarm light notifying the abnormality is turned on, and the process ends.

[0173] In addition, S5-1 and S5-2 may be omitted. In this case, in S5, when it is determined that the clutch contact point θ f If the angle fails to converge within the prescribed angle range, the process proceeds to S5-3, where an alarm lamp notifying of abnormality is turned on, and the process ends.

[0174] In S5, it is determined that the clutch contact point θ f If the current value A of the shift motor 66 is within the predetermined angle range, the process proceeds to S6 to detect the maximum value A of the current value A of the shift motor 66. peak .

[0175] In S7, the maximum value A is determined. peak Is it within the specified range, that is, is it within the specified lower limit A min Above and within the specified upper limit A max the following.

[0176] In S7, when the maximum value A is determined peak Not converging within the specified range, i.e. less than the specified lower limit A min , or greater than the specified upper limit A maxIn the case of, enter S7-1, determine the maximum value A peak Whether the number of abnormal detections j reaches the preset number of times m. peak When the number of abnormality detections j does not reach the prescribed number of times m, that is, is less than m, in S7-2, 1 is added to j and the process returns to S1.

[0177] In S7-1, when it is determined that the maximum value A peak When the number of abnormality detections j reaches the preset number of times m, the process proceeds to S7-3, where the alarm light notifying the abnormality is turned on and the process ends.

[0178] In S7, at the maximum value A peak If it is within the predetermined range, it can be determined that there is no abnormality, and in the next S8 , it is determined whether the rolling element 36 is located at the bottom of the recessed portion constituting the driving cam surface 48 as the initial position.

[0179] If it is determined in S8 that the rolling element 36 is not located at the initial position, the process proceeds to S8-1, and the drive cam 34 is rotationally driven by the shift motor 66 to move the rolling element 36 to the initial position, and then the process returns to S8.

[0180] In S8, if it is determined that the rolling element 36 is located at the initial position, the process ends. In addition, S8 and S8-1 may be omitted. In this case, the maximum value A is determined in S7. peak After converging within the specified range, it ends directly.

[0181] According to the electric friction engagement device 7 of this example, the piston contact point θ can be automatically detected based on the current value A of the shift motor 66. p and the clutch contact point θ f Therefore, the piston contact point θ can be used with high precision. p and / or clutch contact point θ f The electric friction engagement device 7 can be controlled by the piston contact point θ p and / or clutch contact point θ f If an abnormality occurs, it is detected quickly.

[0182] According to the electric friction engagement device 7 of this example, it is possible to determine the clutch contact point θ f Whether the wear of the first friction plate 30 and the second friction plate 31 has reached the use limit is determined by checking whether the wear of the first friction plate 30 and the second friction plate 31 has reached the use limit. Therefore, the first friction plate 30 and the second friction plate 31 can be prevented from being used beyond the use limit of their respective wear amounts, and seizing etc. can be reliably prevented from occurring in the friction engagement portion 26.

[0183] According to the electric friction engagement device 7 of this embodiment, it is possible to determine the maximum value A of the current value A of the shift motor 66. peak Whether it is within a predetermined range, in other words, the maximum value A of the shift motor 66 peak Is it the specified lower limit value A? min Above the upper limit value A max the following.

[0184] When the elastic force of the elastic urging member 27 elastically urging the first friction plate 30 and the second friction plate 31 in the direction of pressing each other, that is, the elastic restoring force of the elastic member 33 is too large, and the meshing state of the worm teeth of the worm 68 and the gear teeth 49 of the drive cam 34 is inappropriate, the maximum value A of the shift motor 66 is peak On the other hand, if the elastic restoring force of the elastic member 33 is too small, the force pressing the first friction plate 30 and the second friction plate 31 against each other is insufficient, and there is a possibility that an abnormality such as failure to ensure sufficient fastening force of the friction engagement portion 26 may occur.

[0185] In the electric friction engagement device 7 of this example, a maximum value A of the current value A of the shift motor 66 is determined. peak The function of whether the control signal is within a predetermined range can be used to detect whether the abnormality described above occurs quickly, thereby reliably preventing the abnormality from causing further failure.

[0186] When the mode of the electric friction engagement device 7 is switched, the output torque T of the shift motor 66 and the current value A of the shift motor 66 change in the same trend. Therefore, when the present disclosure is implemented, the piston contact point and the clutch contact point can be detected based on the output torque of the shift motor instead of the current value of the shift motor, thereby detecting abnormality.

[0187] However, in order to detect the piston contact point and the clutch contact point based on the output torque of the shift motor and further detect abnormality, it is necessary to provide a torque sensor on the output shaft of the shift motor or the like.

[0188] On the other hand, the electric friction engagement device 7 of this example detects the piston contact point θ based on the current value A of the shift motor 66. p and the clutch contact point θ f , and abnormalities. Therefore, there is no need to detect the piston contact point θ only p and the clutch contact point θ f , and abnormalities by providing a torque sensor, the cost of the electric friction engagement device 7 can be reduced.

[0189] Fig.18The actions shown in the flowchart shown can be performed at any time as long as they do not hinder the driving of the vehicle equipped with the two-speed transmission 1. For example, they can be performed when the two-speed transmission is switched from a low reduction ratio mode to a high reduction ratio mode, such as just after the ignition key is turned on, during downshift acceleration, or during engine braking.

[0190] However, when the above operation is to be performed while the vehicle is running, the driving cam 34 cannot be driven at an arbitrary rotation speed. f , maximum value A peak In the case of an abnormality, if the process returns to S1 for re-determination, there is a possibility that the vehicle cannot be accelerated smoothly. Therefore, the above-mentioned operation is preferably performed when the vehicle is stopped, such as immediately after the ignition key is turned on.

[0191] Fig.18 The steps in the flowchart shown can be performed in reverse order or simultaneously unless there is any conflict. For example, steps S4 to S5 and steps S6 to S7 can be performed simultaneously and in parallel while monitoring the current value A of the shift motor 66 .

[0192] According to the two-speed transmission 1 of this example, it is possible to ensure good torque transmission efficiency. The reason for this will be described below.

[0193] In the state where the cam device 28 generates a pressing force, that is, the driven cam 35 presses the piston 32 toward one side in the axial direction via the thrust bearing 57 and the pressing member 58 ( Figure 2 (b)), a force is applied to the thrust bearing 57 toward one axial side. In addition, the reaction force generated by the driven cam 35 pressing the pressing piston 32 toward one axial side is applied to the radial bearing 38 toward the other axial side via the rolling element 36 and the driving cam 34.

[0194] The track wheel 59a constituting one axial side of the thrust bearing 57 is supported on the rotating member 6 via the pressing member 58 and the piston 32, and the track wheel 59b on the other axial side is supported on the fixed portion 10 via the cam device 28, the angular contact ball bearing 39, and the tubular member 37. In addition, the inner ring 42 constituting the radial bearing 38 is externally fitted and fixed to the rotating member 6, and the outer ring 43 is supported on the driving cam 34 of the cam device 28 via the tubular member 37 and the angular contact ball bearing 39.

[0195] In the two-speed transmission 1 of this example, when the cam device 28 generates a pressing force, that is, the piston 32 is pressed toward one side in the axial direction, the axial dimension of the elastic member 33 is elastically reduced, and the force pressing the first friction plate 30 and the second friction plate 31 against each other is released, and the brake device 8 is connected in the state of disconnecting the electric friction engagement device 7. In the high reduction ratio mode in which the electric friction engagement device 7 is disconnected and the brake device 8 is connected, the relative rotation of the rotating member 6 with respect to the fixed portion 10 is prevented.

[0196] In this state, the track wheel 59a on one axial side and the track wheel 59b on the other axial side of the thrust bearing 57 do not rotate relative to each other, and the inner ring 42 and the outer ring 43 of the radial bearing 38 do not rotate relative to each other. Figure 2 When the rolling resistance increases due to the force (in the left and right directions) of (b), the track wheel 59a on one axial side of the thrust bearing 57 and the track wheel 59b on the other axial side do not rotate relative to each other, and the inner ring 42 and the outer ring 43 constituting the radial bearing 38 do not rotate relative to each other.

[0197] Therefore, it is possible to prevent torque loss from occurring in the thrust bearing 57 and the radial bearing 38 .

[0198] The pressing force generated by the cam device 28 is applied to the rotating member 6 in the axial direction from the driven cam 35 via the pressing member 58, the thrust bearing 57, the piston 32, and the elastic member 33 toward one side. In contrast, the reaction force generated by the pressing force generated by the cam device 28 is applied to the rotating member 6 in the axial direction from the driving cam 34 via the radial bearing 38 toward the other side. In this way, the axial forces generated by the pressing force generated by the cam device 28 are offset (cancelled) in the rotating member 6.

[0199] On the other hand, in a state where the brake device 8 is cut off and relative rotation of the rotating member 6 with respect to the fixed portion 10 is allowed ( Figure 2 (a) shows the state), the electric friction engagement device 7 is connected, and the cam device 28 does not generate a pressing force. In this state, the axial direction ( Figure 2 Since the force (in the left-right direction of (a)) is not applied to the thrust bearing 57 and the radial bearing 38, the rolling resistance of the thrust bearing 57 and the radial bearing 38 will not increase unnecessarily, and the torque loss will not increase excessively.

[0200] In summary, in the two-speed transmission 1 of this example, except for a short time in the switching mode, the axial force generated by the pressing force generated by the cam device 28 is applied, and the thrust bearing 57 and the radial bearing 38 do not rotate in a state where the rolling resistance becomes large. Therefore, it is possible to prevent excessive torque loss from occurring in the thrust bearing 57 and the radial bearing 38, and it is possible to ensure good torque transmission efficiency of the two-speed transmission 1.

[0201] The friction engagement device of the present disclosure is not limited to a two-speed transmission for an automobile, but can be assembled and used between a pair of rotating members of various structures, or between a rotating member and a stationary member.

[0202] Explanation of symbols

[0203] 1: 2-stage transmission

[0204] 2: Driving source

[0205] 3: Differential device

[0206] 4: Input components

[0207] 5: Output components

[0208] 6: Rotating parts

[0209] 7: Electric friction engagement device

[0210] 8: Braking device

[0211] 9: Planetary reduction mechanism

[0212] 10: Fixed part

[0213] 11: Output shaft

[0214] 12: Driving gear

[0215] 13: Input gear

[0216] 14: Output gear

[0217] 15: Small diameter flange

[0218] 16: Flange

[0219] 17: Through hole

[0220] 18: First round wheel

[0221] 19: First cylindrical part

[0222] 20: Second round wheel

[0223] 21: Second cylindrical part

[0224] 22: Shaft components

[0225] 23: Stepped cylindrical parts

[0226] 24: Small diameter cylinder

[0227] 25: Internal spline

[0228] 26: Friction engagement part

[0229] 27: Elastic force-applying component

[0230] 28: Cam device

[0231] 29: Electric actuator

[0232] 30: First friction plate

[0233] 31: Second friction plate

[0234] 32: Piston

[0235] 33: Elastic parts

[0236] 34: Driving cam

[0237] 35: Driven cam

[0238] 36: Rolling element

[0239] 37: Cylindrical parts

[0240] 38: Radial bearing

[0241] 39: Angular contact ball bearing

[0242] 40: Cylinder

[0243] 41: Outward flange

[0244] 42: Inner Circle

[0245] 43: Outer ring

[0246] 44: Rolling element

[0247] 45: Inner circle

[0248] 46: Outer ring

[0249] 47: Ball

[0250] 48: Driving cam surface

[0251] 49: Gear teeth

[0252] 50: Sales Department

[0253] 51: Internal spline

[0254] 52: External spline part

[0255] 53: Rectangular hole

[0256] 54a, 54b: Support plate

[0257] 55: Support hole

[0258] 56: Support recess

[0259] 57: Thrust bearing

[0260] 58: Pressing parts

[0261] 59a, 59b: Track wheels

[0262] 60: rolling element

[0263] 61: Pre-pressure application unit

[0264] 62: Base

[0265] 63: Part of the cylindrical part

[0266] 64: Support shaft

[0267] 65: Roller

[0268] 66: Shift motor

[0269] 67: Reducer

[0270] 68: Worm

[0271] 69a, 69b: Support bearing

[0272] 70: Outer diameter side cylindrical parts

[0273] 71: Inner diameter side cylindrical parts

[0274] 72: Selection Board

[0275] 73: Outer circumferential concave-convex part

[0276] 74: Sun gear

[0277] 75: Ring gear

[0278] 76: Planet carrier

[0279] 77: Planetary gear

[0280] 78: Return spring

Claims

1. An electric friction engagement device, characterized in that: have: first component; a second component coaxial with the first component and supported to be rotatable relative to the first component; A friction engagement portion, comprising at least one first friction plate and at least one second friction plate supported to be capable of axial relative displacement, disposed between the first component and the second component, and switching to a state in which torque is transmitted between the first component and the second component by pressing the first friction plate and the second friction plate against each other, and switching to a state in which torque is not transmitted between the first component and the second component by releasing the force pressing the first friction plate and the second friction plate against each other; an elastic force applying member, which is disposed between the first member and the friction engaging portion and elastically applies force to the first friction plate and the second friction plate in a direction of pressing each other; A cam device comprising: a driving cam supported to be rotatable relative to the first member and the second member and not to be axially displaceable; and a driven cam supported to be relatively rotatable and axially displaceable relative to the driving cam, wherein as the driving cam rotates, the driven cam moves in a direction in which the axial interval between the driven cam and the driving cam is enlarged, thereby pressing the elastic force applying member in a direction in which the force pressing the first friction plate and the second friction plate against each other is released; as well as The electric actuator includes a shift motor and a speed reducer, wherein the drive cam is rotationally driven by the shift motor via the speed reducer. The electric friction engagement device comprises: In order to switch the friction engagement portion from a state in which torque is transmitted between the first member and the second member to a state in which torque is not transmitted between the first member and the second member, when the drive cam is rotationally driven by the shift motor via the speed reducer, a function is detected as a piston contact point at which the elastic urging member begins to be pressed in a direction in which the force pressing the first friction plate and the second friction plate against each other is released, when the output torque or current value of the shift motor begins to increase at an increasing rate greater than a first threshold value, in relation to the rotation direction of the drive cam; as well as In order to switch the friction engagement portion from a state in which torque is transmitted between the first component and the second component to a state in which torque is not transmitted between the first component and the second component, when the drive cam is rotationally driven by the shift motor via the reducer, after exceeding the piston contact point, the phase related to the rotation direction of the drive cam when the increase rate becomes below a second threshold value is detected as a clutch contact point in which the force pressing the first friction plate and the second friction plate against each other is zero.

2. The electric friction engagement device according to claim 1, characterized in that: A function of determining whether the piston contact point or the clutch contact point is within a predetermined angle range is provided.

3. The electric friction engagement device according to claim 1, characterized in that: The invention has the function of determining whether the maximum value of the output torque or the current value of the shift motor when the drive cam is rotationally driven by the shift motor via the speed reducer in order to switch the friction engagement portion from a state in which the torque is transmitted between the first component and the second component to a state in which the torque is not transmitted between the first component and the second component, is within a prescribed range.

4. The electric friction engagement device according to claim 1, characterized in that: The elastic urging member includes a piston supported so as to be axially displaceable relative to the first member, and an elastic member provided between the first member and the piston.

5. A contact point detection method for an electric friction engagement device, characterized in that: The electric friction engagement device comprises: first component; a second component coaxial with the first component and supported to be rotatable relative to the first component; A friction engagement portion, comprising at least one first friction plate and a second friction plate, each of which is supported to be relatively displaceable in an axial direction, and is disposed between the first component and the second component, and is switched to a state in which torque is transmitted between the first component and the second component by pressing the first friction plate and the second friction plate against each other, and is switched to a state in which torque is not transmitted between the first component and the second component by releasing the force pressing the first friction plate and the second friction plate against each other; an elastic force applying member, which is disposed between the first member and the friction engaging portion and elastically applies force to the first friction plate and the second friction plate in a direction of pressing each other; A cam device comprising: a driving cam supported to be rotatable relative to the first member and the second member and not to be axially displaceable; and a driven cam supported to be relatively rotatable and axially displaceable relative to the driving cam, wherein as the driving cam rotates, the driven cam moves in a direction in which the axial interval between the driven cam and the driving cam is enlarged, thereby pressing the elastic force applying member in a direction in which the force pressing the first friction plate and the second friction plate against each other is released; as well as The electric actuator includes a shift motor and a speed reducer, wherein the drive cam is rotationally driven by the shift motor via the speed reducer. The contact point detection method of the electric friction engagement device comprises: In order to switch the friction engagement portion from a state in which torque is transmitted between the first member and the second member to a state in which torque is not transmitted between the first member and the second member, when the drive cam is rotationally driven by the shift motor via the speed reducer, a phase related to the rotation direction of the drive cam when the output torque or current value of the shift motor starts to increase at an increasing rate of more than a first threshold value is detected as a piston contact point at which the elastic urging member starts to be pressed in a direction in which the force pressing the first friction plate and the second friction plate against each other is released; as well as In order to switch the friction engagement portion from a state in which torque is transmitted between the first component and the second component to a state in which torque is not transmitted between the first component and the second component, when the drive cam is rotationally driven by the shift motor via the reducer, after exceeding the piston contact point, a phase related to the rotation direction of the drive cam when the increase rate becomes below a second threshold is detected as a clutch contact point at which the force pressing the first friction plate and the second friction plate against each other is zero.

6. A method for detecting abnormality of an electric friction engagement device, characterized in that: The electric friction engagement device comprises: first component; a second component coaxial with the first component and supported to be rotatable relative to the first component; A friction engagement portion, comprising at least one first friction plate and a second friction plate, each of which is supported to be relatively displaceable in an axial direction, and is disposed between the first component and the second component, and is switched to a state in which torque is transmitted between the first component and the second component by pressing the first friction plate and the second friction plate against each other, and is switched to a state in which torque is not transmitted between the first component and the second component by releasing the force pressing the first friction plate and the second friction plate against each other; an elastic force applying member, which is disposed between the first member and the friction engaging portion and elastically applies force to the first friction plate and the second friction plate in a direction of pressing each other; A cam device comprising: a driving cam supported to be rotatable relative to the first member and the second member and not to be axially displaceable; and a driven cam supported to be relatively rotatable and axially displaceable relative to the driving cam, wherein as the driving cam rotates, the driven cam moves in a direction in which the axial interval between the driven cam and the driving cam is enlarged, thereby pressing the elastic force applying member in a direction in which the force pressing the first friction plate and the second friction plate against each other is released; as well as The electric actuator includes a shift motor and a speed reducer, wherein the drive cam is rotationally driven by the shift motor via the speed reducer. The abnormality detection method of the electric friction engagement device comprises: A step of executing the contact point detection method of the electric friction engagement device according to claim 5; and and determining whether the piston contact point or the clutch contact point is greater than a predetermined angle.

7. The abnormality detection method of the electric friction engagement device according to claim 6, characterized in that: The following processes are available: To determine whether a maximum value of an output torque or a current value of the shift motor when the drive cam is rotationally driven by the shift motor via the reducer is within a prescribed range in order to switch the friction engagement portion from a state in which torque is transmitted between the first component and the second component to a state in which torque is not transmitted between the first component and the second component.

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