two-stage transmission

Abstract

The present application realizes the construction of a two-stage transmission that can well ensure the transmission efficiency of torque. The two-stage transmission is provided with an input member that is rotatable relative to a fixed part, an output member that is coaxial with the input member and is relatively rotatable, a rotating member that is coaxial with the above members and is relatively rotatable, a first engagement device that switches the engagement of a first friction plate and a second friction plate to switch the state of the input member and the rotating member to be integrated or relatively rotatable, a second engagement device that switches the state of the rotating member to be rotatable or non-rotatable, an elastic force applying mechanism that applies a force of mutual pressure to the first friction plate and the second friction plate, a pressing device that releases the force of mutual pressure, a first bearing between the elastic force applying mechanism and the pressing device, a second bearing between the rotating member and the pressing device or the fixed part, and a planetary reduction mechanism. The sun element of the planetary reduction mechanism is connected to the input member or the rotating member, the gear carrier is connected to the rotating member or one of the input member and the output member, and the ring element is connected to the other one.

Description

Technical Field

[0001] The present invention relates to a two-stage transmission capable of switching the reduction ratio between the input and output components in two stages. Background Technology

[0002] In recent years, with the trend of reducing fossil fuel consumption, research on electric vehicles and hybrid vehicles has been promoted, and some have been implemented. Unlike internal combustion engines (engines) that operate by directly burning fossil fuels, electric motors, which serve as the power source for electric and hybrid vehicles, generally generate maximum torque at startup. The torque and rotational speed characteristics of their output shafts are preferred for automotive applications, thus eliminating the need for a transmission as in conventional vehicles that use internal combustion engines. However, even when using an electric motor as the drive source, the addition of a transmission can improve acceleration and high-speed performance. Specifically, by incorporating a transmission, the relationship between vehicle speed and acceleration can be made smoother and closer to that of vehicles equipped with an engine and a transmission in the power transmission system. (See reference...) Figure 25 This point needs clarification.

[0003] For example, if a power transmission device with a large reduction ratio is configured between the output shaft of the electric motor and the input section of the differential gear connected to the drive wheel, then when the relationship between the acceleration (G) and the driving speed (km / h) of the electric vehicle is generally shown, it becomes... Figure 25 As shown by solid line a. That is, it has excellent acceleration performance at low speeds, but cannot achieve high-speed driving. To address this, if a power transmission device with a small reduction ratio is installed between the output shaft and the input section, the above relationship becomes... Figure 25 Like dotted line b. That is, it can travel at high speeds, but its acceleration performance at low speeds is compromised. To address this, if a transmission is installed between the output shaft and the input section, and the reduction ratio of the transmission is changed according to the vehicle speed, a characteristic is obtained where the portion of solid line a to the left of point P is continuous with the portion of dotted line b to the right of point P. It can be seen that this characteristic is similar to... Figure 25 The vehicles with the same level of output, as shown by the dashed line c, are roughly the same, and in terms of acceleration and high-speed performance, they have the same performance as vehicles with an engine that has a transmission in the power transmission system.

[0004] Japanese Patent Publication No. 2018-515721 discloses the following structure for a drive system for electric vehicles: a two-stage transmission utilizing a planetary gear mechanism with dual pinions, a clutch (first shifting element), and a freewheel (second shifting element) to increase the output torque of an electric motor and transmit it to the output shaft (axle). This drive system for electric vehicles is configured to switch between a state where the internal gear and the gear carrier of the planetary gear mechanism can rotate relative to each other and a state where they cannot rotate relative to each other, based on the switching of the clutch's engagement / disengagement state. This allows for switching the reduction ratio between the electric motor and the output shaft in two stages, high and low.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2018-515721 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] From the perspective of improving torque transmission efficiency, the device described in Japanese Patent Publication No. 2018-515721 has room for improvement. In this device, the clutch engagement / disengagement state is switched by applying pressure or releasing the mutual pressure between the clutch member supported by the internal gear and the clutch member supported by the gear carrier using a pressing device. Furthermore, in this device, a clutch release bearing is provided between the internal gear and the gear carrier. Therefore, by arranging the planetary gear mechanism in a so-called "glued" state where the sun gear, internal gear, and gear carrier rotate as a single unit, the rolling resistance of the clutch release bearing increases when the clutch member supported by the internal gear and the clutch member supported by the gear carrier are pressed together by the pressing device, potentially increasing the torque loss at the clutch release bearing.

[0010] In view of the above, the object of the present invention is to provide a two-stage transmission having a structure that can effectively ensure torque transmission efficiency.

[0011] Solution for solving the problem

[0012] One embodiment of the present invention provides a two-stage transmission comprising an input component, an output component, a rotating component, a first engaging device, a second engaging device, an elastic force application mechanism, a pressing device, a first bearing, a second bearing, and a planetary reduction mechanism.

[0013] The aforementioned input component is supported and can rotate freely relative to a fixed part that does not rotate during use. Furthermore, the input component is driven to rotate by a drive source such as an electric motor or engine.

[0014] The output component is supported coaxially with the input component and is rotatable relative to the input component. Furthermore, the output component is connected to the input section of a differential device (differential gear) or similar device in a manner capable of transmitting torque.

[0015] The aforementioned rotating component is supported coaxially with the aforementioned input component and the aforementioned output component and is capable of rotating relative to the input component and the aforementioned output component.

[0016] The aforementioned first engaging device has a first friction plate and a second friction plate supported for axial relative displacement, and is disposed between the input component and the rotating component. The first engaging device switches to a state where the input component and the rotating component rotate as a single unit by pressing the first friction plate and the second friction plate against each other, and switches to a state where the input component and the rotating component rotate relative to each other by releasing the force pressing the first friction plate and the second friction plate against each other.

[0017] The second engaging device is disposed between the fixed part and the rotating component, switching between a state in which the rotating component can rotate relative to the fixed part and a state in which it cannot rotate.

[0018] The aforementioned elastic force-applying mechanism is disposed between the aforementioned rotating component and the aforementioned first engaging device, and applies force elastically in the direction that presses the aforementioned first friction plate and the aforementioned second friction plate against each other.

[0019] The pressing device is disposed between the fixed part and the rotating component, and presses the elastic force-applying mechanism in the direction of releasing the force that presses the first friction plate and the second friction plate against each other.

[0020] The first bearing is disposed between the elastic force-applying mechanism and the pressing device.

[0021] The second bearing is disposed between the rotating component and the pressing device or the fixed part.

[0022] The aforementioned planetary deceleration mechanism has a solar element, an annular element disposed around the solar element, a gear carrier disposed radially between the solar element and the annular element, and a plurality of planetary elements that engage with the solar element and the annular element in a manner capable of transmitting torque and are rotatably supported by the gear carrier.

[0023] In a two-stage transmission according to one aspect of the present invention, the aforementioned solar element is connected to the aforementioned input component or the aforementioned rotating component in a manner capable of transmitting torque, the aforementioned gear carrier is connected to the aforementioned rotating component or a component of either the aforementioned input component or the aforementioned output component in a manner capable of transmitting torque, and the aforementioned annular element is connected to the other component of either the aforementioned rotating component or the aforementioned input component or the aforementioned output component in a manner capable of transmitting torque.

[0024] In a two-stage transmission according to one aspect of the present invention, when the rotating component is not rotating relative to the fixed portion, the pressing device presses the elastic force-applying mechanism in the direction of releasing the force that presses the first friction plate and the second friction plate against each other.

[0025] In a two-stage transmission according to one aspect of the present invention, the elastic force-applying mechanism has a pressing plate supported to be axially displaced relative to the rotating member, and an elastic member disposed between the rotating member and the pressing plate.

[0026] One embodiment of the present invention provides a two-stage transmission with a preload application mechanism disposed between the first bearing and the rotating component, which applies axial preload to the first bearing.

[0027] In a two-stage transmission according to one embodiment of the present invention, the solar element is connected to the rotating component in a manner capable of transmitting torque, the annular element is connected to the input component in a manner capable of transmitting torque, and the gear carrier is connected to the output component in a manner capable of transmitting torque.

[0028] In a two-stage transmission according to one embodiment of the present invention, the solar element is connected to the input component in a manner capable of transmitting torque, the annular element is connected to the rotating component in a manner capable of transmitting torque, and the gear carrier is connected to the output component in a manner capable of transmitting torque.

[0029] In a two-stage transmission according to one aspect of the present invention, the planetary element comprises: a first planetary element that engages with the solar element in a manner capable of transmitting torque; and a second planetary element that engages with the annular element in a manner capable of transmitting torque, and also engages with the first planetary element in a manner capable of transmitting torque.

[0030] In this case, the solar element can be connected to the rotating component in a manner that can transmit torque, the annular element can be connected to the output component in a manner that can transmit torque, and the gear carrier can be connected to the input component in a manner that can transmit torque.

[0031] Alternatively, the solar element can be connected to the input component in a manner that can transmit torque, the annular element can be connected to the output component in a manner that can transmit torque, and the gear carrier can be connected to the rotating component in a manner that can transmit torque.

[0032] In a two-stage transmission according to one embodiment of the present invention, the aforementioned solar element is constituted by a sun gear, the aforementioned annular element is constituted by a ring gear, and the aforementioned planetary element is constituted by a planetary gear. That is, the aforementioned planetary reduction mechanism is constituted by a planetary gear mechanism.

[0033] Alternatively, the aforementioned solar element can be composed of a solar roller, the aforementioned annular element can be composed of an annular roller, and the aforementioned planetary element can be composed of a planetary roller. That is, the aforementioned planetary deceleration mechanism can also be composed of a friction roller mechanism.

[0034] The aforementioned second engagement device can be composed of a meshing clutch, a friction clutch, a one-way clutch including a free wheel, etc.

[0035] The aforementioned pressing device can include a cam mechanism, a hydraulic cylinder mechanism, etc.

[0036] The aforementioned first bearing can be constructed from a thrust rolling bearing. More specifically, the thrust rolling bearing can be constructed from a thrust ball bearing, a thrust needle roller bearing, a thrust cylindrical roller bearing, a thrust tapered roller bearing, a thrust angular contact ball bearing, etc.

[0037] The aforementioned second bearing can be, for example, a thrust rolling bearing or a radial rolling bearing capable of withstanding thrust loads. More specifically, the aforementioned thrust rolling bearing can be composed of thrust ball bearings, thrust needle roller bearings, thrust cylindrical roller bearings, thrust tapered roller bearings, thrust angular contact ball bearings, etc. The aforementioned radial rolling bearing can be composed of radial ball bearings, radial tapered roller bearings, radial angular contact ball bearings, etc.

[0038] The effects of the invention are as follows.

[0039] The two-stage transmission according to one embodiment of the present invention can effectively ensure torque transmission efficiency. Attached Figure Description

[0040] Figure 1 This is a schematic cross-sectional view of a drive system incorporating a two-stage transmission according to a first embodiment of the present invention.

[0041] Figure 2 (a) is a schematic cross-sectional view showing the torque transmission path in the low reduction ratio mode of the two-stage transmission in the first example. Figure 2 (b) is a schematic cross-sectional view showing the torque transmission path in the high reduction ratio mode of the two-stage transmission in the first example.

[0042] Figure 3 This is a 3D diagram of the first example of a two-stage transmission.

[0043] Figure 4 This is a cross-sectional view of the first example of a two-stage transmission.

[0044] Figure 5 This is a perspective view showing the planetary gear mechanism of the second-stage transmission in the first example after it has been removed.

[0045] Figure 6 yes Figure 5 The cross-sectional view of the two-stage transmission shown.

[0046] Figure 7 yes Figure 5 The diagram shown is an exploded perspective view of the two-stage transmission.

[0047] Figure 8 This is a perspective view showing the state of the worm gear and a pair of support bearings of the first example of a two-stage transmission before they are combined.

[0048] Figure 9 This is an exploded perspective view of the first engagement device of the first two-stage transmission.

[0049] Figure 10 yes Figure 4 Enlarged view of the X-section.

[0050] Figure 11 This is a three-dimensional view of the drive cam of the first example of a two-stage transmission.

[0051] Figure 12 This is an exploded perspective view of the driven cam and rolling elements of the first example of a two-stage transmission.

[0052] Figure 13 (a) is a perspective view of the flange portion and the pressing component of the rotating component constituting the two-stage transmission in the first example. Figure 13 (b) is an exploded perspective view of the flange and the pressing component.

[0053] Figure 14 This is a schematic cross-sectional view of a drive system incorporating a second example of an embodiment of the present invention, specifically a two-stage transmission.

[0054] Figure 15 This is a schematic cross-sectional view of a drive system incorporating a third embodiment of the present invention, specifically a two-stage transmission.

[0055] Figure 16 (a) is a schematic cross-sectional view showing the torque transmission path in the low reduction ratio mode of the second-stage transmission in the third example. Figure 16(b) is a schematic cross-sectional view showing the torque transmission path in the high reduction ratio mode of the second-stage braiding machine in the third example.

[0056] Figure 17 This is a schematic cross-sectional view of a drive system incorporating a second-stage transmission according to a fourth embodiment of the present invention.

[0057] Figure 18 (a) is a schematic cross-sectional view showing the torque transmission path in the low reduction ratio mode of the second-stage transmission in the fourth example. Figure 18 (b) is a schematic cross-sectional view showing the torque transmission path in the high reduction ratio mode of the second-stage transmission in the fourth example.

[0058] Figure 19 This is a cross-sectional view of the second-stage transmission in the fourth example.

[0059] Figure 20 This is a schematic cross-sectional view of a drive system incorporating a second-stage transmission according to a fifth embodiment of the present invention.

[0060] Figure 21 (a) is a schematic cross-sectional view showing the torque transmission path in the low reduction ratio mode of the second-stage transmission in the fifth example. Figure 21 (b) is a schematic cross-sectional view showing the torque transmission path in the high reduction ratio mode of the second-stage transmission in the fifth example.

[0061] Figure 22 This is a schematic cross-sectional view of a drive system incorporating a second-stage transmission according to a sixth embodiment of the present invention.

[0062] Figure 23 This is a schematic cross-sectional view of a drive system incorporating a second-stage transmission according to a seventh embodiment of the present invention.

[0063] Figure 24 (a) is a schematic cross-sectional view showing the torque transmission path in the low reduction ratio mode of the second-stage transmission in the seventh example. Figure 24 (b) is a schematic cross-sectional view showing the torque transmission path in the high reduction ratio mode of the second-stage transmission in the seventh example.

[0064] Figure 25 It is a line diagram used to illustrate the effect produced by incorporating a drive unit that uses an electric motor as the drive source into a transmission. Detailed Implementation

[0065] [First example]

[0066] use Figures 1 to 13(b) will describe a first example of an embodiment of the present invention. In this example, the two-stage transmission 1 is disposed between a drive source 2 such as an electric motor or engine and a differential device 3, increasing (reducing) the output torque of the drive source 2 and transmitting it to the differential device 3, or transmitting it directly to the differential device 3 without increasing the output torque. The two-stage transmission 1 includes an input component 4, an output component 5, a rotating component 6, a first engaging device 7, a second engaging device 8, an elastic force application mechanism 9, a pressing device 10, a first bearing 11, a second bearing 12, and a planetary reduction mechanism 13.

[0067] The input component 4 is constructed from a housing that houses the two-stage transmission 1, and is rotatable relative to the fixed part 14, which does not rotate during use, by rolling bearings (not shown). In this example, the input component 4 is cylindrical (hollow). Furthermore, the input component 4 is axially positioned on one side... Figure 1 The right end of the input component 4 has an input gear 17 that meshes with the drive gear 16 of the output shaft 15 of the drive source 2. That is, the input component 4 can be driven to rotate by the drive source 2.

[0068] The output component 5 is supported coaxially with the input component 4 and is rotatable relative to the input component 4. In this example, the output component 5 is supported radially inside the cylindrical input component 4 via a rolling bearing (not shown) or the like, in a manner that allows it to rotate relative to the input component 4. Furthermore, the output component 5 has an output gear 18 at one end on its axial side. The output gear 18 meshes with a gear included in the input section of the differential device 3. That is, the output component 5 is connected to the input section of the differential device 3 in a manner capable of transmitting torque.

[0069] The rotating component 6 is supported coaxially with the input component 4 and the output component 5 and is capable of rotating relative to the input component 4 and the output component 5. In this example, the rotating component 6 is supported relative to the fixed part 14 via the second engaging device 8, the pressing device 10, and the second bearing 12 described below.

[0070] In this example, the rotating component 6 has a small-diameter flange 19 protruding radially outward at its axial midpoint, and on the other side axially relative to the small-diameter flange 19... Figure 1The portion located on the left side has a flange 20 that protrudes radially outward. The flange 20 is a hollow circular plate and has the following features at multiple locations in the radial middle: a first circular portion 21 having a partially arc-shaped through hole 64 for inserting the pressing member 41 described below; a first cylindrical portion 22 that is bent from the radially outer end of the first circular portion 21 toward the other axial side; a hollow circular plate-shaped second circular portion 23 that is bent radially outward from the axially other end of the first cylindrical portion 22; and a second cylindrical portion 24 that is bent axially outward from the radially outer end of the second circular portion 23.

[0071] In this example, the rotating component 6 with flange 20 is fixed by being externally fitted onto the shaft component 69 with small-diameter flange 19. Figure 13 The stepped cylindrical member 70 shown on the left side of (b) is constructed. That is, the stepped cylindrical member 70 is a hollow circular plate, and has a first circular portion 21 with a through hole 64, a first cylindrical portion 22, a second circular portion 23, a second cylindrical portion 24, and a small-diameter cylindrical portion 74 bent from the radially inner end of the first circular portion 21 toward the axial side. The inner spline portion 71 provided on the inner circumferential surface of the small-diameter cylindrical portion 74 of the rotating member 6 engages with the outer spline portion spline provided on the outer circumferential surface of the shaft member 69.

[0072] The first engaging device 7 has multiple first friction plates 25 and multiple second friction plates 26 supported for axial relative displacement, and is disposed between the input component 4 and the rotating component 6. That is, the first engaging device 7 is constituted by a multi-plate clutch, which is formed by alternately overlapping the first friction plates 25 supported by the input component 4 and the second friction plates 26 supported by the rotating component 6. The first engaging device 7 can be switched to a state where the first friction plates 25 and second friction plates 26 are pressed against each other and connected, causing the input component 4 and the rotating component 6 to rotate as a unit, or to a state where the force pressing the first friction plates 25 and second friction plates 26 against each other is released and disconnected, causing the input component 4 and the rotating component 6 to rotate relative to each other.

[0073] In this example, the first friction plate 25 is supported on the inner circumferential surface of the end of the input component 4 on the other side of the axial direction in a manner that allows for axial displacement. The second friction plate 26 located on the other side of the axial direction is supported on the outer circumferential surface of the first cylindrical portion 22 of the rotating component 6 in a manner that prevents axial displacement, while the other second friction plates 26 are supported on the outer circumferential surface of the first cylindrical portion 22 in a manner that allows for axial displacement.

[0074] The second engaging device 8 is disposed between the fixed part 14 and the rotating part 6, switching between a state in which the rotating part 6 can rotate relative to the fixed part 14 and a state in which it cannot rotate. In this example, the second engaging device 8 is disposed between the inner circumferential surface of the fixed part 14 and the second cylindrical portion 24 of the rotating part 6.

[0075] The second engagement device 8 can be, for example, a meshing or friction clutch (brake) whose disengagement state can be switched by an actuator. The actuator used to switch the disengagement state of the clutch is not particularly limited; a hydraulic actuator, an electromagnetic actuator, etc., can be used. As explained below, the second engagement device 8 is disengaged in a low reduction ratio mode with the first engagement device 7 connected, and engaged in a high reduction ratio mode with the first engagement device 7 disengaged.

[0076] In this example, such as Figure 4 and Figure 6 As shown, the second engaging device 8 includes an outer diameter cylindrical component 75, an inner diameter cylindrical component 76, at least one engaging pin (not shown), and a selection plate 77.

[0077] like Figure 3 and Figure 5 As shown, the outer diameter cylindrical member 75 has an outer peripheral concave-convex portion 78 on its outer circumferential surface, in which concave portions and convex portions are alternately arranged in the circumferential direction. The outer diameter cylindrical member 75 is supported so that it cannot rotate relative to the fixed portion 14 by engaging the outer peripheral concave-convex portion 78 with the inner peripheral concave-convex portion provided on the inner circumferential surface of the fixed portion 14.

[0078] The inner diameter cylindrical component 76 is externally fixed relative to the second cylindrical portion 24 of the rotating component 6 in a manner that prevents relative rotation.

[0079] A locking pin is engaged and disengaged between the outer diameter cylindrical member 75 and the inner diameter cylindrical member 76. In this example, the locking pin is supported relative to the outer diameter cylindrical member 75 in a radially inward protrusion from the inner circumferential surface of the outer diameter cylindrical member 75 and subjected to a resilient force in the radially inward direction. Furthermore, the inner diameter cylindrical member 76 has an engaging recess on its outer circumferential surface that engages the front end of the locking pin.

[0080] The selection plate 77 has a mode selection section with concave and convex portions in the circumferential direction, and is configured to be driven to rotate by the electric motor 30 described below via the drive cam 31.

[0081] The second engaging device 8 switches between a state where the outer diameter cylindrical member 75 and the inner diameter cylindrical member 76 can rotate relative to each other, or a state where they cannot rotate relative to each other, based on the rotation of the selection plate 77. That is, based on the rotation of the selection plate 77, the engaging pin is lifted radially outward by the protrusion constituting the mode selection portion, thereby releasing the engagement between the engaging pin and the engaging recess. This allows the inner diameter cylindrical member 76 to rotate relative to the outer diameter cylindrical member 75, and also allows the rotating member 6 to rotate relative to the fixed portion 14. Conversely, based on the rotation of the selection plate 77, the protrusion constituting the mode selection portion moves circumferentially away from the front end of the engaging pin, thereby engaging the engaging pin with the engaging recess. This prevents the rotation of the inner diameter cylindrical member 76 relative to the outer diameter cylindrical member 75, and also prevents the rotation of the rotating member 6 relative to the fixed portion 14.

[0082] The elastic force-applying mechanism 9 is disposed between the rotating component 6 and the first engaging device 7, and elastically applies force in the direction that causes the first friction plate 25 and the second friction plate 26 to press against each other. In this example, the elastic force-applying mechanism 9 has a pressing plate 27 and an elastic component 28.

[0083] In this example, the pressing plate 27 is configured as a hollow circular plate and is supported around the portion of the rotating member 6 between the small-diameter flange portion 19 and the flange portion 20 in the axial direction, in a manner that allows for axial displacement relative to the rotating member 6. Furthermore, the pressing plate 27 is positioned such that the end face of the radially outer portion on the other axial side faces the axial side of the second friction plate 26 located on the most axially adjacent side.

[0084] In this example, the elastic member 28 is held in an elastically compressed state between the other axial side of the small-diameter flange 19 of the rotating member 6 and one axial side of the pressing plate 27. That is, the elastic force application mechanism 9 uses the force of the elastic member 28 to elastically recover, pressing the second friction plate 26 closest to the axial side towards the other axial side via the pressing plate 27, thereby elastically applying force in the direction that causes the first friction plate 25 and the second friction plate 26 to press against each other. The elastic member 28 can be made of a disc spring, a torsion coil spring, or the like.

[0085] The pressing device 10 is disposed between the fixed part 14 and the rotating part 6, and presses the elastic force-applying mechanism 9 in the direction of releasing the force that releases the mutual pressing of the first friction plate 25 and the second friction plate 26. In this example, the pressing device 10 has a cam device 29 and an electric motor 30.

[0086] The cam device 29 has a driving cam 31, a driven cam 32, and a plurality of rolling elements 33. In this example, as... Figure 10As shown, a roller is used as the rolling element 33, and the rolling element 33 is supported relative to the driven cam 32 so that it can freely rotate about a rotation axis C (spinning), wherein the rotation axis C is oriented in a radial direction centered on the central axis of the driven cam 32. Furthermore, Figures 1-2 In (b), the cam device 29 is schematically shown for ease of understanding of the invention.

[0087] like Figure 11 As shown, the drive cam 31 has a drive cam surface 34 with an equal number of concave and convex portions alternately arranged in the circumferential direction on the radially inner portion of its axial single side, and has gear teeth 35 on its outer circumferential surface, which are helical gears. The drive cam 31 is supported relative to the rotating member 6 by the angular contact ball bearing 91, the cylindrical member 84, and the second bearing 12, enabling it to rotate relative to the rotating member 6. Furthermore, the drive cam 31 has pin portions 90 protruding towards the axial single side at multiple circumferential locations (three locations in the illustrated example) in the radially middle portion of its axial single side. The front end of the pin portion 90 engages (loosely embedded) with the engagement hole provided on the selection plate 77. Thus, the drive cam 31 rotates integrally with the selection plate 77 (in the same direction and at the same speed).

[0088] like Figure 12 As shown, the driven cam 32 is configured as a hollow circular plate, with rectangular holes 79 extending axially through multiple locations (three locations in the illustrated example) in the radially central circumferential direction. It also has generally semi-circular plate-shaped support plates 80a and 80b that protrude axially from the radially opposite sides of each rectangular hole 79. The radially outer support plate portions 80a each have support holes 81 that are radially through circular holes, and the radially inner support plate portions 80b each have support recesses 82 with circular openings on their radially outer surfaces. The driven cam 32 is arranged around the rotating member 6 in a manner that allows only axial displacement. Specifically, the driven cam 32 is supported relative to the fixed part 14 and is capable of axial displacement by engaging an inner spline portion 83 on its inner circumferential surface with an outer spline portion 85 on the outer circumferential surface of the cylindrical member 84, which is supported and fixed by the fixed part 14.

[0089] Multiple rolling elements 33 are each cylindrical in shape and are supported relative to support plates 80a and 80b via a cylindrical support shaft 86 and multiple rollers 87, allowing them to rotate freely. Specifically, one axial end of the support shaft 86 (the outer end radially centered on the central axis of the driven cam 32) is fitted and fixed to a support hole 81 in the radially outer support plate 80a, and the other axial end of the support shaft 86 (the inner end radially centered on the central axis of the driven cam 32) is fitted and fixed to a support recess 82 in the radially inner support plate 80b. The multiple rollers 87 are rolled freely between the inner circumferential surface of the rolling element 33 and the outer circumferential surface of the axial middle portion of the support shaft 86. Thus, the rolling element 33 is supported by the driven cam 32 and rotates freely about a rotation axis C, wherein the rotation axis C is oriented radially towards the central axis of the driven cam 32.

[0090] like Figure 10 As shown, with the rolling elements 33 supported on the driven cam 32, the portions of each rolling element 33, except for those located on the other axial side of the driven cam 32, are disposed inside the rectangular hole 79. Furthermore, the outer peripheral surface of each rolling element 33 is in rolling contact with the drive cam surface 34 provided on one axial side of the drive cam 31 on the other axial side of the driven cam 32.

[0091] In the cam device 29, as the drive cam 31 rotates, the rolling element 33 rises from the bottom of the recess constituting the drive cam surface 34 by an increasing or decreasing amount, thereby driving the cam 32 to move axially.

[0092] Alternatively, the rolling element 33 can be made of balls. In this case, in addition to the driving cam surface 34, or instead of the driving cam surface 34, a driven cam surface with an equal number of concave and convex portions alternately arranged in the circumferential direction is formed on the other side of the driven cam 32.

[0093] The worm 38, connected to the output shaft of the electric motor 30, meshes with the gear teeth 35 provided on the outer peripheral surface of the drive cam 31. This allows the electric motor 30 to drive the drive cam 31 to rotate. The worm 38 is supported by a pair of support bearings 88a and 88b, allowing it to rotate freely relative to the fixed part 14. In this example, the threaded worm 38 meshes with the gear teeth 35, which are helical gears. However, it is also possible to drive the drive cam to rotate by the electric motor by meshing the spur gear or bevel gear on the output shaft of the electric motor with the spur gear or bevel gear on the drive cam, or by installing a belt or chain between the output shaft of the electric motor and the drive cam.

[0094] A first bearing 11 is disposed between the elastic force-applying mechanism 9 and the pressing device 10. The first bearing 11 has a pair of track rings 39a and 39b and a plurality of rolling elements 40 freely disposed therebetween. More specifically, the first bearing 11 is disposed between the cylindrical pressing member 41 of the pressing plate 27 connected to the elastic force-applying mechanism 9 and the driven cam 32 of the pressing device 10. Figure 13 As shown in (b), the pressing member 41 has a cylindrical base 72 and a partial cylindrical portion 73 that protrudes axially to one side from a circumferentially portion (three portions in the illustrated example) from one axially unilateral end of the base 72. In this example, the axially unilateral track ring 39a is supported and fixed at the other axially unilateral end of the base 72, and the front end (the axially unilateral end) of the partial cylindrical portion 73 is positioned opposite the radially central portion of the other axially unilateral side of the pressing plate 27.

[0095] In the illustrated example, the first bearing 11 is constructed from a one-way thrust ball bearing that uses balls as rolling elements 40. However, in implementing the present invention, the first bearing 11 can also be constructed from thrust rolling bearings such as thrust angular contact ball bearings, thrust needle roller bearings, thrust roller bearings, and thrust tapered roller bearings. Furthermore, the thrust bearing applied to the first bearing 11 can also be constructed from a bearing unit composed of multiple bearings.

[0096] The second bearing 12 is disposed between the rotating component 6 and the pressing device 10. In this example, the second bearing 12, the cylindrical component 84, and the angular contact ball bearing 91 are provided between the rotating component 6 and the drive cam 31 of the pressing device 10. The second bearing 12 is composed of multiple rows of ball bearings, having an inner ring 43 externally fixed to the rotating component 6, an outer ring 44 internally fixed to the cylindrical component 84, and a plurality of rolling elements 45 freely disposed between the inner ring 43 and the outer ring 44. The angular contact ball bearing 91 has an inner ring 92 externally fixed to the cylindrical component 84, an outer ring 93 internally fixed to the drive cam 31, and a plurality of rolling elements 94 freely disposed between the inner ring 92 and the outer ring 93. Furthermore, Figure 1 The cylindrical component 84 and the angular contact ball bearing 91 are omitted.

[0097] In the illustrated example, the second bearing 12 is constructed from a single-row deep groove ball bearing using balls as rolling elements 45. However, in implementing the present invention, the structure of the second bearing 12 is not particularly limited as long as it allows for relative rotation between the rotating component and the pressing device and can withstand the axial force of the elastic force-applying mechanism. As the second bearing 12, radial rolling bearings capable of withstanding thrust loads, such as deep groove ball bearings, radial angular contact ball bearings, and radial tapered roller bearings, can also be used instead. Furthermore, thrust rolling bearings such as thrust ball bearings, thrust needle roller bearings, thrust roller bearings, thrust tapered roller bearings, and thrust angular contact ball bearings can also be used as the second bearing 12. Additionally, the second bearing 12 can also be constructed from a bearing unit composed of multiple bearings.

[0098] In implementing the present invention, it is also possible to support and fix a component constituting the pressing device (e.g., a drive cam) on one of the pair of track rings constituting the second bearing (e.g., the outer ring), and to support and fix a rotating component on the other track ring (e.g., the inner ring).

[0099] The planetary reduction mechanism 13 has a sun gear 46 as a solar element, a ring gear 47 as a ring element, a gear carrier 48 as a gear carrier element, and a plurality of planetary gears 49, each as a planetary element. That is, in this example, the planetary reduction mechanism 13 is composed of a single-pinion type planetary gear mechanism.

[0100] The sun gear 46 is connected to the rotating component 6 in a manner capable of transmitting torque. In this example, the sun gear 46 is located at one end of the rotating component 6 on one side of the axial direction.

[0101] The gear ring 47 is coaxially disposed around the sun gear 46 and connected to the input component 4 in a manner capable of transmitting torque. In this example, the gear ring 47 is located at the axial midpoint of the input component 4.

[0102] The gear carrier 48 is arranged radially coaxially between the sun gear 46 and the ring gear 47, and is connected to the output component 5 in a manner that enables torque transmission.

[0103] Multiple planetary gears 49 mesh with the sun gear 46 and the ring gear 47 respectively, and are supported by the gear carrier 48 in a rotatable manner about their own central axis.

[0104] The two-stage transmission 1 in this example also includes a preload application mechanism 89, which is disposed between the first bearing 11 and the rotating component 6 to apply axial preload to the first bearing 11, which serves as a thrust bearing. In this example, the preload application mechanism 89 is held in an elastically compressed state between one axial side of the track ring 39a of the pair of track rings 39a and 39b constituting the first bearing 11 and the other axial side of the first circular portion 21 of the flange portion 20 constituting the rotating component 6. Thus, as Figure 2 As shown in (b), even when the pressing plate 27 is pressed against one side of the axial direction to overcome the elastic force of the elastic member 28, a preload is applied to the first bearing 11, and the first bearing 11 is prevented from falling off between the elastic force application mechanism 9 and the pressing device 10.

[0105] In this example, the two-stage transmission 1 can switch between a low reduction ratio mode (reduction ratio of 1) with a smaller reduction ratio between the input component 4 and the output component 5, or a high reduction ratio mode with a larger reduction ratio compared to the low reduction ratio mode, by switching the disconnected state of the first engagement device 7 and the disconnected state of the second engagement device 8. The following explains each case.

[0106] <Low Reduction Ratio Mode>

[0107] In order to switch the secondary transmission 1 to a low reduction ratio mode, the first engagement device 7 is engaged and the second engagement device 8 is disengaged.

[0108] Specifically, such as Figure 2 As shown in (a), the drive cam 31 is driven by the electric motor 30 to rotate in a direction where the amount of rise of the rolling element 33 from the bottom of the recess constituting the drive cam surface 34 decreases. This releases the force exerted by the driven cam 32 on the press plate 27 axially to one side via the first bearing 11 and the pressing member 41. When the force exerted on the press plate 27 axially to one side is released, the elastic restoring force of the elastic member 28 presses the press plate 27, the first bearing 11, and the pressing member 41 axially to the other side, and the press plate 27 presses the second friction plate 26 closest to the axial side axially to the other side. As a result, the first friction plate 25 and the second friction plate 26 press against each other, the first engaging device 7 connects, and the input member 4 and the rotating member 6 rotate integrally. Therefore, the sun gear 46 and the ring gear 47 rotate integrally.

[0109] Furthermore, by operating the actuator, the second engaging device 8 is disengaged, thereby allowing the rotating member 6 to rotate relative to the fixed portion 14. As a result, the sun gear 46 is allowed to rotate relative to the fixed portion 14.

[0110] In this low reduction ratio mode, the sun gear 46, ring gear 47, and gear carrier 48 rotate in the same direction and at the same speed, forming a so-called "glued" state where the planetary reduction mechanism 13 rotates as a whole. Therefore, the torque of the input component 4 is transmitted through... Figure 2 The path shown by the thick line in (a) does not increase (decelerate) but is directly transmitted to the output unit 5. In other words, in the low reduction ratio mode, the reduction ratio between the input unit 4 and the output unit 5 is 1.

[0111] <High Reduction Ratio Mode>

[0112] In order to switch the secondary transmission 1 to a high reduction ratio mode, the first engagement device 7 is disconnected and the second engagement device 8 is connected.

[0113] Specifically, such as Figure 2 As shown in (b), the drive cam 31, driven by the electric motor 30, rotates in a direction that increases the upward movement of the rolling element 33 from the bottom of the recess constituting the drive cam surface 34. Consequently, the driven cam 32 presses the pressing plate 27 axially to one side via the first bearing 11 and the pressing member 41, causing the axial dimension of the elastic member 28 to elastically contract, releasing the force of the first friction plate 25 and the second friction plate 26 pressing against each other. As a result, the distance between the first friction plate 25 and the second friction plate 26 increases, thereby disengaging the first engaging device 7, allowing the input member 4 and the rotating member 6 to rotate relative to each other. Therefore, the sun gear 46 and the ring gear 47 can rotate relative to each other.

[0114] Furthermore, by operating the actuator to engage the second engaging device 8, the relative rotation of the rotating component 6 with respect to the fixed portion 14 is prevented. As a result, the rotation of the sun gear 46 with respect to the fixed portion 14 is also prevented.

[0115] In this high reduction ratio mode, the torque of input component 4 is transmitted through... Figure 2 The path shown in bold in (b) is the rotational motion of the input component 4, the ring gear 47, and the planetary gear 49, the revolution of the planetary gear 49 based on its meshing with the sun gear 46, and the path through the gear carrier 48 to the output component 5.

[0116] In the high reduction ratio mode, the torque of the input component 4 is increased by the planetary reduction mechanism 13 and transmitted to the output component 5. Furthermore, the reduction ratio between the input component 4 and the output component 5 in the high reduction ratio mode is determined by the gear ratio of the ring gear 47 and the sun gear 46 (number of teeth on the ring gear 47 / number of teeth on the sun gear 46).

[0117] In this example, the two-stage transmission 1 can switch the reduction ratio between the input component 4 and the output component 5 in two stages—high and low—by switching the disconnection states of the first engagement device 7 and the second engagement device 8. Specifically, in the region where the torque input to the input component 4 is low speed and high torque, the two-stage transmission 1 is switched to a high reduction ratio mode; in the region where the torque input to the input component 4 is high speed and low torque, the two-stage transmission 1 is switched to a low reduction ratio mode. Therefore, the acceleration and high-speed performance of electric vehicles and hybrid vehicles, which only use the electric motor as a drive source, can become a key factor in their performance. Figure 25 The characteristic that the portion of solid line a to the left of point P is continuous with the portion of dashed line b to the right of point P is that they are close together. Figure 25 The characteristics of the gasoline engine vehicle are shown by the dashed line c.

[0118] When switching the mode of the secondary transmission 1, it is not necessary to switch the disconnection state of the first engagement device 7 and the second engagement device 8 completely simultaneously in time; the switching can be slightly staggered. That is, the tightening force and timing of the first engagement device 7 and the second engagement device 8 can be appropriately adjusted to reduce the shift shock caused by the mode switching of the secondary transmission 1.

[0119] The two-stage transmission 1 in this example can effectively ensure torque transmission efficiency. The reasons for this are explained below.

[0120] When the pressing device 10 generates pressing force, that is, when the driven cam 32 presses the pressing plate 27 axially to one side via the first bearing 11 and the pressing member 41 ( Figure 2 In the state shown in (b), a force is applied to the first bearing 11 in one axial direction. And, the reaction force generated by the driven cam 32 pressing the pressing plate 27 in one axial direction is applied to the second bearing 12 in the other axial direction via the rolling element 33 and the driving cam 31.

[0121] The track ring 39a on one axial side of the first bearing 11 is supported by the rotating member 6 via the pressing member 41 and the pressing plate 27, while the track ring 39b on the other axial side is supported by the fixing part 14 via the cam device 29, the angular contact ball bearing 91, and the cylindrical member 84. Furthermore, the inner ring 43 of the second bearing 12 is externally fixed to the rotating member 6, and the outer ring 44 is supported by the drive cam 31 of the cam device 29 via the cylindrical member 84 and the angular contact ball bearing 91.

[0122] In the two-stage transmission 1 of this example, when the pressing device 10 generates pressing force, that is, when the pressing plate 27 is pressed axially to one side and the elastic member 28 elastically contracts in the axial dimension, releasing the force that causes the first friction plate 25 and the second friction plate 26 to press against each other and thus cutting off the first engaging device 7, the second engaging device 8 is engaged. In the high reduction ratio mode where the first engaging device 7 is cut off and the second engaging device 8 is engaged, relative rotation of the rotating member 6 relative to the fixed part 14 is prevented. In this state, the track ring 39a constituting the first bearing 11 on one axial side and the track ring 39b on the other axial side do not rotate relative to each other, and the inner ring 43 constituting the second bearing 12 and the outer ring 44 do not rotate relative to each other. In summary, axial ( Figure 2 When the force (b) in the left-right direction increases, the rolling resistance increases. In this state, the track ring 39a on one axial side of the first bearing 11 and the track ring 39b on the other axial side do not rotate relative to each other, and the inner ring 43 and the outer ring 44 of the second bearing 12 do not rotate relative to each other. Therefore, torque loss in the first bearing 11 and the second bearing 12 can be prevented.

[0123] Furthermore, the pressing force generated by the pressing device 10 is applied to the rotating member 6 in a uniaxial direction from the driven cam 32 via the pressing member 41, the first bearing 11, the pressing plate 27, and the elastic member 28. Conversely, the reaction force generated by the pressing force generated by the pressing device 10 is applied to the rotating member 6 in the opposite axial direction from the driving cam 31 via the second bearing 12. Thus, the axial forces generated by the pressing force generated by the pressing device 10 cancel each other out within the rotating member 6.

[0124] On the other hand, in the state where the second engaging device 8 is disengaged, allowing the rotating component 6 to rotate relative to the fixed portion 14 ( Figure 2 In the state shown in (a), the first engaging device 7 is connected, and the pressing device 10 does not generate pressing force. In this state, no axial force is applied to the first bearing 11 and the second bearing 12 as would be required by the pressing force generated by the pressing device 10. Figure 2 The force in the left and right directions of (a) will prevent the rolling resistance of the first bearing 11 and the second bearing 12 from becoming too large, and thus the torque loss will not become too large.

[0125] In summary, in the two-stage transmission 1 of this example, except for the brief period during mode switching, the axial force generated by the pressing force produced by the pressing device 10 is applied, increasing the rolling resistance. Under these conditions, the first bearing 11 and the second bearing 12 will not rotate. Therefore, excessive torque loss in the first bearing 11 and the second bearing 12 can be prevented, thereby ensuring the torque transmission efficiency of the two-stage transmission 1.

[0126] In this example, a roller is used as the rolling element 33, and the rolling element 33 is supported relative to the driven cam 32 so that it can freely rotate about a rotation axis C (rotation), wherein the rotation axis C is oriented in a radial direction centered on the central axis of the driven cam 32. Therefore, by rotating the drive cam 31, the driven cam 32 can be reliably displaced axially. That is, when using balls as the rolling elements constituting the cam device, when the drive cam is rotated, slippage may occur at the rolling contact portion between the surface of the rolling element and the drive cam surface and / or the driven cam surface. When slippage occurs at the rolling contact portion between the surface of the rolling element and the drive cam surface and / or the driven cam surface, the driven cam may not be able to displace axially, or the amount of axial displacement of the driven cam formed by the rotation relative to the drive cam may not be sufficiently ensured.

[0127] In this example, when the drive cam 31 is rotated, slippage at the rolling contact between the outer peripheral surface of the rolling element 33 and the drive cam surface 34 can be prevented. Based on the rotation of the drive cam 31, the driven cam 32 can be reliably displaced axially. As a result, mode switching of the two-stage transmission 1 can be reliably performed. However, as described above, ball bearings can be used as the rolling elements constituting the cam device.

[0128] In this example, the second engagement device 8 uses a clutch capable of switching between disengaged and engaged states using an actuator. However, in implementing this invention, it is not particularly limited to simply disengaging the second engagement device in a low reduction ratio mode where the first engagement device is engaged and engaging it in a high reduction ratio mode where the first engagement device is disengaged; various clutch configurations known to date can be used. For example, the second engagement device can also be a one-way clutch including a freewheel. When using a one-way clutch without an actuator as the second engagement device, the second engagement device is configured to allow the rotating member to rotate in the same direction as the rotation direction of the input member when the vehicle is moving forward, and to prevent the rotating member from rotating in the opposite direction to the rotation direction of the input member when the vehicle is moving forward.

[0129] In this example, the pressing device 10 includes a cam device 29 that holds the rolling element 33 between the driving cam 31 and the driven cam 32, and an electric motor 30. However, in implementing the present invention, the pressing device is not particularly limited as long as it can press the elastic force-applying mechanism in the direction of releasing the force pressing the first friction plate and the second friction plate against each other. Various types of pressing devices can be used. For example, as a pressing device, the following cam devices can also be used: a cam device that directly engages (slides) the driving cam surface of the driving cam with the driven cam surface of the driven cam; and a cam device having a driven cam and a driving cam, wherein the driven cam has a guide groove that extends along the circumferential direction on the outer circumferential surface and varies in the axial direction, and the driving cam has an engaging protrusion that can engage in a manner that allows it to be displaced along the guide groove. Alternatively, a hydraulic cylinder device can also be used as a pressing device.

[0130] In this example, a single-pinion planetary gear mechanism is used as the planetary reduction mechanism 13. However, in implementing the present invention, a double-pinion planetary gear mechanism can also be used as the planetary reduction mechanism. Alternatively, the planetary reduction mechanism can be constituted by a friction roller mechanism, which has a sun roller, an annular roller disposed around the sun roller, and a planetary roller disposed radially between the sun roller and the annular roller, such that its outer peripheral rolling surface is rubbed against the outer peripheral surface of the sun roller and the inner peripheral surface of the annular roller.

[0131] [Second Example]

[0132] use Figure 14 A second example of an embodiment of the present invention will be described. In this example, a hollow output component 5a is supported around a solid input component 4a in a manner that allows it to rotate relative to the input component 4a, and a hollow rotating component 6a is supported around the output component 5a in a manner that allows it to rotate relative to the output component 5a.

[0133] The input component 4a and the output shaft of the drive source 2 are integrated into one unit.

[0134] The output component 5a is connected to the input part of the differential device 3 via the intermediate transmission shaft 50 in a manner that enables torque transmission. That is, the output gear 18 of the output component 5a meshes with the large-diameter gear 51 of the intermediate transmission shaft 50, and the small-diameter gear 52 of the intermediate transmission shaft 50 meshes with the gear of the input part of the differential device 3.

[0135] In the illustrated example, the axial direction of the second-stage transmission 1 is... Figure 1In the first example shown, the axial direction of the two-stage transmission 1 is reversed (left-right reversal). In this example, the axial force generated by the pressing force produced by the pressing device 10 is also canceled out (counteracted) within the rotating member 6a and / or the fixed part 14. The structure and function of the other parts are the same as in the first example.

[0136] [Third Case]

[0137] use Figures 15-16 (b) A third example of an embodiment of the present invention will be described. In the two-stage transmission 1a of this example, the sun gear 46 is connected to the input component 4b in a manner that can transmit torque, the ring gear 47 is connected to the rotating component 6b in a manner that can transmit torque, and the gear carrier 48 is connected to the output component 5b in a manner that can transmit torque.

[0138] The rotating component 6b has a small-diameter flange 19a protruding radially inward at its axial midpoint, and on the other axial side ( Figure 15 The left end of the flange 20a has a flange portion 20a that protrudes radially inward. The flange portion 20a has: a hollow circular plate-shaped first circular portion 21a; a first cylindrical portion 22a that bends from the radially inward end of the first circular portion 21a toward the other axial side; a hollow circular plate-shaped second circular portion 23a that bends from the axially other end of the first cylindrical portion 22a toward the radially inward side; and a second cylindrical portion 24a that bends from the radially inward end of the second circular portion 23a toward the other axial side.

[0139] In this example, the multiple first friction plates 25 constituting the first engaging device 7 are supported on the outer peripheral surface of the end of the input member 4b on the opposite axial side in a manner that allows for axial displacement. The second friction plate 26 located on the opposite axial side among the multiple second friction plates 26 is supported on the inner peripheral surface of the first cylindrical portion 22a of the rotating member 6b in a manner that prevents axial displacement, while the other second friction plates 26 are supported on the inner peripheral surface of the first cylindrical portion 22a in a manner that allows for axial displacement.

[0140] The second engaging device 8 is disposed between the inner circumferential surface of the fixed part 14 and the second cylindrical part 24a of the rotating part 6b.

[0141] In this example, the pressing device 10a includes a cylinder device 53 and a direction switching valve 54.

[0142] The cylinder assembly 53 is constructed by mounting a piston 56 in a cylinder 55, and has a pair of hydraulic chambers 57a and 57b disposed within the cylinder 55 with the piston 56 between them. Furthermore, a first bearing 11 and a pressing member 41 are provided between the piston 56 and the pressing plate 27 of the elastic force application mechanism 9.

[0143] Based on the energization of the solenoid 58, the directional switching valve 54 switches to a state in which the hydraulic chamber of one of the pair of hydraulic chambers 57a and 57b is connected to the hydraulic source 59 to increase the hydraulic pressure and the hydraulic chamber of the other is connected to the oil reservoir 60 to release the hydraulic pressure, or the opposite state.

[0144] <Low Reduction Ratio Mode>

[0145] To switch the secondary transmission 1a in this example to a low reduction ratio mode, as follows: Figure 16 As shown in (a), the directional switching valve 54 is operated by energizing the solenoid 58, connecting the hydraulic chamber 57a on one axial side to the hydraulic source 59 to increase the hydraulic pressure, and connecting the hydraulic chamber 57b on the other axial side to the oil reservoir 60 to release the hydraulic pressure. This releases the force exerted by the piston 56 on the pressing plate 27 on one axial side via the first bearing 11 and the pressing member 41. When the force exerted on the pressing plate 27 on one axial side is released, the elastic restoring force of the elastic member 28 presses the pressing plate 27, the first bearing 11, and the pressing member 41 on the other axial side, and the pressing plate 27 presses the second friction plate 26 closest to the one axial side on the other axial side. As a result, the first friction plate 25 and the second friction plate 26 press against each other, the first engaging device 7 engages, and the input member 4b and the rotating member 6b rotate as a unit. Therefore, the sun gear 46 and the ring gear 47 rotate as a unit.

[0146] Additionally, by operating the actuator to disengage the second engagement device 8, the rotating member 6b is allowed to rotate relative to the fixed portion 14, thereby allowing the sun gear 46 to rotate relative to the fixed portion 14.

[0147] As a result, the sun gear 46, ring gear 47, and gear carrier 48 rotate in the same direction and at the same speed, forming a so-called "glued" state in which the planetary reduction mechanism 13 rotates as a whole. The torque of the input component 4b is transmitted through... Figure 16 The path shown by the thick line in (a) will not increase (decelerate) but will be directly transmitted to the output component 5b.

[0148] <High Reduction Ratio Mode>

[0149] To switch the secondary transmission 1a in this example to high reduction ratio mode, as follows: Figure 16As shown in (b), the directional switching valve 54 is operated by energizing the solenoid 58, connecting the hydraulic chamber 57a on one axial side to the oil reservoir 60 to release hydraulic pressure, and connecting the hydraulic chamber 57b on the other axial side to the hydraulic source 59 to increase hydraulic pressure. Consequently, the piston 56 presses the pressing plate 27 towards one axial side via the first bearing 11 and the pressing member 41, causing the axial dimension of the elastic member 28 to elastically contract, releasing the force of the first friction plate 25 and the second friction plate 26 pressing against each other. As a result, the distance between the first friction plate 25 and the second friction plate 26 is widened by the action of the return spring, thereby disengaging the first engaging device 7, allowing the input member 4b and the rotating member 6b to rotate relative to each other. Therefore, the sun gear 46 and the ring gear 47 can rotate relative to each other.

[0150] Additionally, by operating the actuator to engage the second engaging device 8, the rotation of the rotating member 6b relative to the fixed portion 14 is prevented, and the rotation of the gear ring 47 relative to the fixed portion 14 is also prevented.

[0151] In this high reduction ratio mode, the torque of input component 4b is transmitted through... Figure 16 The path shown by the thick line in (b) is the rotational motion of the input component 4b, the sun gear 46, and the planetary gear 49, the revolution of the planetary gear 49 based on its meshing with the ring gear 47, and the path through the gear carrier 48, which is transmitted to the output component 5b. That is, in the high reduction ratio mode, the torque of the input component 4b is increased by the planetary reduction mechanism 13 and transmitted to the output component 5b.

[0152] Similarly, in the two-stage transmission 1a of this example, except for the brief time during mode switching, an axial force generated by the pressing force produced by the pressing device 10a is applied, increasing the rolling resistance. In this state, the first bearing 11 and the second bearing 12 will not rotate. Therefore, excessive torque loss in the first bearing 11 and the second bearing 12 can be prevented, thereby ensuring the torque transmission efficiency of the two-stage transmission 1a. The structure and function of the other parts are the same as in the first example.

[0153] [Fourth Case]

[0154] use Figures 17-19 A fourth example of an embodiment of the present invention will be described. In this example, the two-stage transmission 1b has a sun gear 46 connected to the input component 4c in a manner that can transmit torque, a ring gear 47 connected to the rotating component 6c in a manner that can transmit torque, and a gear carrier 48 connected to the output component 5c in a manner that can transmit torque.

[0155] Input component 4c is on one side of the axial direction ( Figure 17The input member 4c has an input gear 17 at its right end. A sun gear 46 is disposed at the axial middle portion of the input member 4c. Furthermore, the input member 4c has a portion located axially on the opposite side from the portion containing the sun gear 46. Figure 17 The flange portion 61 (the left side portion) bends radially outward; and the cylindrical portion 62 bends radially outward from the end of the flange portion 61 toward the other side axially. Multiple first friction plates 25 constituting the first engaging device 7 are supported on the inner circumferential surface of the end of the cylindrical portion 62 on the other side axially in a manner that allows for axial displacement.

[0156] The rotating component 6c has a small-diameter flange portion 19b protruding radially outward at one end in the axial direction, and a flange portion 20b protruding radially outward at the middle part in the axial direction. The flange portion 20b has: a hollow circular plate-shaped first circular portion 21; a first cylindrical portion 22 bent radially outward from the radially outer end of the first circular portion 21 towards the other side in the axial direction; a hollow circular plate-shaped second circular portion 23 bent radially outward from the other end of the first cylindrical portion 22; a second cylindrical portion 24 bent radially outward from the middle part of the second circular portion 23 towards the other side in the axial direction; and a third cylindrical portion 63 bent radially outward from the radially outer end of the second circular portion 23 towards one side in the axial direction. A gear ring 47 is provided at the axially unilateral end of the third cylindrical portion 63.

[0157] <Low Reduction Ratio Mode>

[0158] To switch the secondary transmission 1b in this example to a low reduction ratio mode, as follows: Figure 18 As shown in (a), by connecting the first engaging device 7, the input component 4c and the rotating component 6c rotate as a unit, thereby causing the sun gear 46 and the ring gear 47 to rotate as a unit. Furthermore, by disengaging the second engaging device 8, the rotating component 6c is allowed to rotate relative to the fixed portion 14, thereby allowing the ring gear 47 to rotate relative to the fixed portion 14.

[0159] As a result, the sun gear 46, ring gear 47, and gear carrier 48 rotate in the same direction and at the same speed, forming a so-called "glued" state in which the planetary reduction mechanism 13 rotates as a whole. The torque of the input component 4 is transmitted through... Figure 18 The path shown by the thick line in (a) will not increase (decelerate) but will be directly transmitted to the output component 5.

[0160] <High Reduction Ratio Mode>

[0161] To switch the secondary transmission 1b in this example to high reduction ratio mode, as follows: Figure 18As shown in (b), by disengaging the first engaging device 7, relative rotation between the input component 4c and the rotating component 6c is allowed, thereby allowing relative rotation between the sun gear 46 and the ring gear 47. Furthermore, by engaging the second engaging device 8, rotation of the rotating component 6c relative to the fixed portion 14 is prevented, thereby preventing rotation of the ring gear 47 relative to the fixed portion 14.

[0162] In this high reduction ratio mode, the torque of the input component 4c is transmitted through... Figure 18 The path shown by the thick line in (b) is the rotational motion of the input component 4c, the sun gear 46, and the planetary gear 49, the revolution of the planetary gear 49 based on its meshing with the ring gear 47, and the path through the gear carrier 48, which is transmitted to the output component 5c. That is, in the high reduction ratio mode, the torque of the input component 4c is increased by the planetary reduction mechanism 13 and transmitted to the output component 5c.

[0163] Similarly, in the two-stage transmission 1b of this example, except for the brief time during mode switching, an axial force generated by the pressing force produced by the pressing device 10 is applied, increasing the rolling resistance. In this state, the first bearing 11 and the second bearing 12 will not rotate. Therefore, excessive torque loss in the first bearing 11 and the second bearing 12 can be prevented, thereby ensuring the torque transmission efficiency of the two-stage transmission 1b. The structure and function of the other parts are the same as in the first example.

[0164] [Fifth Case]

[0165] use Figures 20-21 (b) A fifth example of an embodiment of the present invention will be described. In this example, the planetary reduction mechanism 13a has a sun gear 46 as a sun element, a ring gear 47 as a ring element, a gear carrier 48 as a gear carrier element, a plurality of first planetary gears 49a as first planetary elements, and second planetary gears 49b as second planetary elements. That is, in this example, the planetary reduction mechanism 13a is composed of a double pinion planetary gear mechanism.

[0166] Multiple first planetary gears 49a and multiple second planetary gears 49b mesh with each other as a pair, and are rotatably supported by a gear carrier 48 about their own central axes. Furthermore, the first planetary gear 49a, located radially inward, meshes with the sun gear 46, and the second planetary gear 49b, located radially outward, meshes with the ring gear 47.

[0167] In the two-stage transmission 1c of this example, the sun gear 46 is connected to the rotating component 6d in a manner that can transmit torque, the ring gear 47 is connected to the output component 5d in a manner that can transmit torque, and the gear carrier 48 is connected to the input component 4d in a manner that can transmit torque.

[0168] <Low Reduction Ratio Mode>

[0169] To switch the secondary transmission 1c in this example to a low reduction ratio mode, as follows: Figure 21 As shown in (a), by connecting the first engaging device 7, the input component 4d and the rotating component 6d rotate as a unit, thereby causing the sun gear 46 and the ring gear 47 to rotate as a unit. Furthermore, by disengaging the second engaging device 8, the rotating component 6d is allowed to rotate relative to the fixed portion 14, thereby allowing the ring gear 47 to rotate relative to the fixed portion 14.

[0170] As a result, the sun gear 46, ring gear 47, and gear carrier 48 rotate in the same direction and at the same speed, forming a so-called "glued" state in which the planetary reduction mechanism 13a rotates as a whole. The torque of the input component 4d is transmitted through... Figure 21 The path shown by the thick line in (a) will not increase (decelerate) but will be directly transmitted to the output component 5d.

[0171] <High Reduction Ratio Mode>

[0172] To switch the secondary transmission 1c in this example to high reduction ratio mode, as follows: Figure 21 As shown in (b), by disengaging the first engaging device 7, relative rotation between the input component 4d and the rotating component 6d is allowed, thereby allowing relative rotation between the sun gear 46 and the ring gear 47. Furthermore, by engaging the second engaging device 8, rotation of the rotating component 6d relative to the fixed portion 14 is prevented, thereby preventing rotation of the sun gear 46 relative to the fixed portion 14.

[0173] In this high reduction ratio mode, the torque of the input component 4d is transmitted through... Figure 21 The path shown by the thick line in (b) – namely, the revolution of the input component 4d, gear carrier 48, first planetary gear 49a, and second planetary gear 49b, the rotation of the first planetary gear 49a based on its meshing with the sun gear 46, the rotation of the second planetary gear 49b, and the path through the ring gear 47 – is transmitted to the output component 5d. That is, in the high reduction ratio mode, the torque of the input component 4d is increased by the planetary reduction mechanism 13 and transmitted to the output component 5d.

[0174] Similarly, in the two-stage transmission 1c of this example, except for the brief time during mode switching, an axial force generated by the pressing force produced by the pressing device 10 is applied, increasing the rolling resistance. In this state, the first bearing 11 and the second bearing 12 will not rotate. Therefore, excessive torque loss in the first bearing 11 and the second bearing 12 can be prevented, thereby ensuring the torque transmission efficiency of the two-stage transmission 1c. The structure and function of the other parts are the same as in the first example.

[0175] [Sixth Case]

[0176] use Figure 22 A sixth embodiment of the present invention will be described. In this example, the output component 5d is connected to the input section of the differential device 3 via an intermediate transmission shaft 50 in a manner capable of transmitting torque. That is, the output gear 18 of the output component 5d meshes with the large-diameter gear 51 of the intermediate transmission shaft 50, and the small-diameter gear 52 of the intermediate transmission shaft 50 meshes with the gear of the input section of the differential device 3. The structure and effects of the other parts are the same as in the first and fifth examples.

[0177] [Seventh Case]

[0178] use Figures 23-24 (b) A seventh example of an embodiment of the present invention will be described. The two-stage transmission 1d in this example includes a dual-pinion planetary reduction mechanism 13a. In this example, the sun gear 46 is connected to the input component 4e in a torque-transmitting manner, the ring gear 47 is connected to the output component 5e in a torque-transmitting manner, and the gear carrier 48 is connected to the rotating component 6e in a torque-transmitting manner. Furthermore, the output component 5e is connected to the input section of the differential device 3 via an intermediate transmission shaft 50 in a torque-transmitting manner.

[0179] <Low Reduction Ratio Mode>

[0180] To switch the second-stage transmission 1d in this example to a low reduction ratio mode, as follows: Figure 24 As shown in (a), by connecting the first engaging device 7, the input component 4e and the rotating component 6e rotate as a unit, thereby allowing the sun gear 46 and the gear carrier 48 to rotate as a unit. Furthermore, by disengaging the second engaging device 8, the rotating component 6b is allowed to rotate relative to the fixed portion 14, thereby allowing the gear carrier 48 to rotate relative to the fixed portion 14.

[0181] As a result, the sun gear 46, ring gear 47, and gear carrier 48 rotate in the same direction and at the same speed, forming a so-called "glued" state in which the planetary reduction mechanism 13a rotates as a whole. The torque of the input component 4e is transmitted through... Figure 24The path shown by the thick line in (a) will not increase (decelerate) but will be directly transmitted to the output component 5e.

[0182] <High Reduction Ratio Mode>

[0183] To switch the second-stage transmission 1d in this example to high reduction ratio mode, as follows: Figure 24 As shown in (b), by disengaging the first engaging device 7, relative rotation between the input component 4e and the rotating component 6e is allowed, thereby allowing relative rotation between the sun gear 46 and the gear carrier 48. Furthermore, by engaging the second engaging device 8, rotation of the rotating component 6e relative to the fixed portion 14 is prevented, thereby preventing rotation of the gear carrier 48 relative to the fixed portion 14.

[0184] In this high reduction ratio mode, the torque of the input component 4e is transmitted through... Figure 24 The path shown by the thick line in (b) is the path through the input component 4e, the sun gear 46, the rotational motion of the first planetary gear 49a, the rotational motion of the second planetary gear 49b, and the path through the ring gear 47, which is transmitted to the output component 5e. That is, in the high reduction ratio mode, the torque of the input component 4e is increased by the planetary reduction mechanism 13a and transmitted to the output component 5e.

[0185] Similarly, in the two-stage transmission 1d of this example, except for the brief time during mode switching, an axial force generated by the pressing force produced by the pressing device 10 is applied, increasing the rolling resistance. In this state, the first bearing 11 and the second bearing 12 will not rotate. Therefore, excessive torque loss in the first bearing 11 and the second bearing 12 can be prevented, thereby ensuring the torque transmission efficiency of the two-stage transmission 1d. The structure and effects of other parts are the same as in the first, third, and fifth examples.

[0186] The above-described embodiments can be appropriately combined and implemented without creating contradictions.

[0187] Explanation of symbols

[0188] 1, 1a, 1b, 1c, 1d—Two-stage transmission; 2—Drive source; 3—Differential device; 4, 4a, 4b, 4c, 4d, 4e—Input components; 5, 5a, 5b, 5c, 5d, 5e—Output components; 6, 6a, 6b, 6c, 6d, 6e—Rotating components; 7—First engaging device; 8—Second engaging device; 9—Elastic force application mechanism; 10, 10a—Pressing device; 11—First bearing; 12—Second bearing; 13, 13a—Planetary reduction mechanism; 14—Fixed part; 15—Output shaft; 16—Drive gear; 17—Input gear; 18— Output gear, 19, 19a, 19b—small diameter flange portion, 20, 20a, 20b—flange portion, 21, 21a—first circular portion, 22, 22a—first cylindrical portion, 23, 23a—second circular portion, 24, 24a—second cylindrical portion, 25—first friction plate, 26—second friction plate, 27—pressing plate, 28—elastic component, 29—cam device, 30—electric motor, 31—drive cam, 32—driven cam, 33—rolling element, 34—drive cam surface, 35—gear tooth, 38—worm gear, 39a, 39b—track ring, 40—rolling element, 4 1—Pressing component, 43—Inner ring, 44—Outer ring, 45—Rolling element, 46—Sun gear, 47—Gear ring, 48—Gear carrier, 49—Planet gear, 49a—First planetary gear, 49b—Second planetary gear, 50—Intermediate transmission shaft, 51—Large diameter gear, 52—Small diameter gear, 53—Cylinder assembly, 54—Direction switching valve, 55—Cylinder, 56—Piston, 57a, 57b—Hydraulic chamber, 58—Solenoid, 59—Hydraulic source, 60—Oil well, 61—Flange, 62—Cylindrical section, 63—Third cylindrical section, 64—Through hole, 69—Shaft assembly, 70— A stepped cylindrical component, 71—inner spline portion, 72—base portion, 73—partial cylindrical portion, 74—small diameter cylindrical portion, 75—outer diameter side cylindrical component, 76—inner diameter side cylindrical component, 77—selection plate, 78—outer peripheral side concave-convex portion, 79—rectangular hole, 80a, 80b—support plate portion, 81—support hole, 82—support recess, 83—inner spline portion, 84—cylindrical component, 85—outer spline portion, 86—support shaft, 87—roller, 88a, 88b—support bearing, 89—preload application mechanism, 90—pin portion, 91—angular contact ball bearing, 92—inner ring, 93—outer ring.

Claims

1. A two-stage transmission, characterized in that, have: The input component is supported to rotate freely relative to a fixed part that does not rotate during use; An output component is supported coaxially with the input component and is rotatable relative to the input component; A rotating component, which is supported coaxially with the input component and the output component and is capable of rotating relative to the input component and the output component; The first engaging device has a first friction plate and a second friction plate supported to allow for axial relative displacement, and is disposed between the input component and the rotating component. By pressing the first friction plate and the second friction plate against each other, the device switches to a state in which the input component and the rotating component rotate as a unit. Furthermore, by releasing the force of the first friction plate and the second friction plate pressing against each other, the device switches to a state in which the input component and the rotating component rotate relative to each other. The second engaging device is disposed between the fixed part and the rotating part, and switches between the state in which the rotating part can rotate relative to the fixed part and the state in which it cannot rotate. An elastic force-applying mechanism is disposed between the rotating component and the first engaging device, and applies force elastically in the direction that presses the first friction plate and the second friction plate against each other; The pressing device is disposed between the fixed part and the rotating part, and presses the elastic force application mechanism in the direction of releasing the force that releases the mutual pressing of the first friction plate and the second friction plate. A first bearing is disposed between the aforementioned elastic force-applying mechanism and the aforementioned pressing device; A second bearing is disposed between the rotating component and the pressing device or the fixed part; and A planetary reduction mechanism includes a solar element, an annular element disposed around the solar element, a gear carrier radially disposed between the solar element and the annular element, and a plurality of planetary elements that are engaged with the solar element and the annular element and rotatably supported by the gear carrier in a manner capable of transmitting torque. The aforementioned solar element is connected to the aforementioned input component or the aforementioned rotating component in a manner capable of transmitting torque; the aforementioned gear carrier is connected to the aforementioned rotating component or one of the aforementioned input component and the aforementioned output component in a manner capable of transmitting torque; and the aforementioned annular element is connected to the other of the aforementioned rotating component or the aforementioned input component and the aforementioned output component in a manner capable of transmitting torque.

2. The two-stage transmission according to claim 1, characterized in that, When the rotating component does not rotate relative to the fixed part, the pressing device presses the elastic force-applying mechanism in the direction of releasing the force that presses the first friction plate and the second friction plate against each other.

3. The two-stage transmission according to claim 1, characterized in that, The aforementioned elastic force-applying mechanism has a pressing plate supported so as to be axially displaced relative to the aforementioned rotating component, and an elastic component disposed between the aforementioned rotating component and the aforementioned pressing plate.

4. The two-stage transmission according to claim 1, characterized in that, It also includes a preload application mechanism, which is disposed between the first bearing and the rotating component to apply axial preload to the first bearing.

5. The two-stage transmission according to claim 1, characterized in that, The aforementioned solar element is connected to the aforementioned rotating component in a manner that enables torque transmission, the aforementioned annular element is connected to the aforementioned input component in a manner that enables torque transmission, and the aforementioned gear carrier is connected to the aforementioned output component in a manner that enables torque transmission.

6. The two-stage transmission according to claim 1, characterized in that, The aforementioned solar element is connected to the aforementioned input component in a manner that enables torque transmission, the aforementioned annular element is connected to the aforementioned rotating component in a manner that enables torque transmission, and the aforementioned gear carrier is connected to the aforementioned output component in a manner that enables torque transmission.

7. The two-stage transmission according to claim 1, characterized in that, The aforementioned planetary elements include: a first planetary element that engages with the aforementioned solar element in a manner capable of transmitting torque; and a second planetary element that engages with the aforementioned annular element in a manner capable of transmitting torque, and also engages with the aforementioned first planetary element in a manner capable of transmitting torque.

8. The two-stage transmission according to claim 7, characterized in that, The aforementioned solar element is connected to the aforementioned rotating component in a manner that enables torque transmission, the aforementioned annular element is connected to the aforementioned output component in a manner that enables torque transmission, and the aforementioned gear carrier is connected to the aforementioned input component in a manner that enables torque transmission.

9. The two-stage transmission according to claim 7, characterized in that, The aforementioned solar element is connected to the aforementioned input component in a manner that enables torque transmission, the aforementioned annular element is connected to the aforementioned output component in a manner that enables torque transmission, and the aforementioned gear carrier is connected to the aforementioned rotating component in a manner that enables torque transmission.

10. The two-stage transmission according to any one of claims 1 to 9, characterized in that, The aforementioned solar element is composed of a solar gear, the aforementioned annular element is composed of a gear ring, and the aforementioned planetary element is composed of a planetary gear.

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