Two-gear transmission and electric vehicle driving device

Abstract

The invention provides a two-speed transmission and an electric vehicle driving device, which can easily realize miniaturization of the electric vehicle driving device equipped with the two-speed transmission. A two-speed transmission (2) is provided with a transmission input element (5), a transmission output element (6), a planetary reduction mechanism (7), a first shift mechanism (8), and a second shift mechanism (9). The planetary reduction mechanism (7) is disposed between the transmission input element (5) and the transmission output element (6) in the axial direction of the transmission input element (5).

Description

TECHNICAL FIELD

[0001] The present application relates to a two-speed transmission capable of switching a reduction ratio between a transmission input element and a transmission output element in two stages, and a drive device for an electric vehicle provided with the two-speed transmission. BACKGROUND

[0002] In recent years, in line with a trend of reducing the consumption of fossil fuels, research on electric vehicles and hybrid vehicles is being developed and some are being implemented. Unlike an internal combustion engine (engine) that operates by directly combusting fossil fuels, an electric motor, which is a power source for electric vehicles and hybrid vehicles, generally generates maximum torque at start-up, and the torque and rotational speed characteristics of the output shaft are preferred for use in vehicles, and thus a transmission like that of a typical vehicle that uses an internal combustion engine as a drive source does not necessarily need to be provided. However, even in the case of using an electric motor as a drive source, by providing a transmission, it is possible to improve acceleration performance and high-speed performance. Specifically, by providing a transmission, it is possible to make the relationship between the running speed and the acceleration of a vehicle closer to that of a vehicle that mounts an engine and has a transmission in the power transmission system. Referring to Figure 16 This point will be described.

[0003] For example, if a power transmission device with a large reduction ratio is provided between the motor output shaft of the electric motor and the differential input element of a differential device connected to the drive wheels, the relationship between the acceleration (G) and the running speed (km / h) of the electric vehicle when schematically shown is as shown by the solid line a in Figure 16 . That is, while the acceleration performance at low speed is excellent, high-speed running is not possible. In contrast, if a power transmission device with a small reduction ratio is provided between the motor output shaft and the differential input element, the above relationship is as shown by the dotted line b in Figure 16 . That is, while high-speed running is possible, the acceleration performance at low speed is impaired. In contrast, if a transmission is provided between the motor output shaft and the differential input element, and the reduction ratio of the transmission is changed according to the vehicle speed, a characteristic is obtained in which the left side portion of the point P in the solid line a and the right side portion of the point P in the dotted line b are continuous. This characteristic is roughly equivalent to that of an engine vehicle with the same level of output shown by the dashed line c in Figure 16 , and with respect to acceleration performance and high-speed performance, it is known that by providing a transmission in the power transmission system, performance equivalent to that of an engine vehicle can be obtained.

[0004] A configuration of a drive device for an electric vehicle is disclosed in International Publication No. 2016 / 150411, which transmits output torque of an electric motor to a wheel shaft with the output torque increased by a two-speed transmission. The two-speed transmission has an input gear, an output gear, a double-pinion type planetary gear reducer, a first shift mechanism, and a second shift mechanism. The two-speed transmission is capable of switching a reduction ratio between the input gear and the output gear in two stages, high and low, by switching a mode of the first shift mechanism and a mode of the second shift mechanism.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: International Publication No. 2016 / 150411 SUMMARY

[0008] Problems to be Solved by the Invention

[0009] In the two-speed transmission described in International Publication No. 2016 / 150411, the output gear is disposed between the input gear and the planetary gear reducer in the axial direction of the input gear. Therefore, the electric motor needs to be disposed close to the input gear having an outer diameter larger than that of the output gear. Thus, the position where the electric motor is disposed is limited, and the degree of freedom in design is limited, which can make the entire drive device for an electric vehicle large.

[0010] An object of the present disclosure is to achieve a configuration that easily achieves miniaturization of a drive device for an electric vehicle assembled with a two-speed transmission capable of stepwise switching a reduction ratio between a transmission input element and a transmission output element.

[0011] Means for Solving the Problems

[0012] The two-speed transmission according to one aspect of the present invention has a transmission input element, a transmission output element, a planetary reduction mechanism, a first shift mechanism, and a second shift mechanism.

[0013] The transmission input element is supported so as to be rotatable.

[0014] The transmission output element is supported so as to be coaxial with the transmission input element and rotatable relative to the transmission input element.

[0015] The planetary reduction mechanism has a sun element, a ring element, a planetary carrier, and a plurality of planetary elements.

[0016] The sun element is supported so as to be coaxial with the transmission input element and rotatable relative to the transmission input element and the transmission output element.

[0017] The ring element is disposed coaxially with the sun element around the sun element.

[0018] The planetary gear carrier is disposed coaxially with the sun element.

[0019] The plurality of planetary elements are engaged with the sun element and the ring element so as to transmit torque and are rotatably supported by the planetary gear carrier with the central axis of each planetary element as the center.

[0020] The first element among the sun element, the ring element, and the planetary gear carrier is connected to the transmission input element so as to rotate integrally, and the second element among the sun element, the ring element, and the planetary gear carrier is connected to the transmission output element so as to rotate integrally.

[0021] The first shift mechanism is provided between the first element and a third element among the sun element, the ring element, and the planetary gear carrier, and switches between a disconnection mode in which the first element and the third element are relatively rotatable and a connection mode in which the first element and the third element are not relatively rotatable.

[0022] The second shift mechanism is provided between a fixed portion that does not rotate in use and the third element, and switches between a free mode in which the third element is rotatable with respect to the fixed portion and a lock mode in which the third element is not rotatable with respect to the fixed portion.

[0023] In particular, in the two-speed transmission according to one aspect of the present application, the planetary reduction mechanism is disposed between the transmission input element and the transmission output element in the axial direction of the transmission input element.

[0024] In the two-speed transmission according to one aspect of the present application, the transmission input element can have an input cylinder portion, and at least a part of the first shift mechanism and / or the second shift mechanism can be disposed radially inward of the input cylinder portion.

[0025] In the two-speed transmission according to one aspect of the present application, the plurality of planetary elements can include a plurality of first planetary elements that are engaged with the sun element so as to transmit torque, and a plurality of second planetary elements that are engaged with the ring element so as to transmit torque and are engaged with the plurality of first planetary elements so as to transmit torque. That is, the planetary reduction mechanism can be constituted by a double pinion type planetary reduction mechanism.

[0026] In this case, the first element can be constituted by the planetary gear carrier, the second element can be constituted by the ring element, and the third element can be constituted by the sun element.

[0027] Alternatively, the first element can be composed of the sun element, the second element can be composed of the ring element, and the third element can be composed of the planetary carrier.

[0028] Alternatively, in the two-speed transmission according to an aspect of the present application, the plurality of planetary elements can be engaged with both the sun element and the ring element in a torque-transmitting manner, respectively. That is, the planetary reduction mechanism can be composed of a single-pinion type planetary reduction mechanism.

[0029] In this case, the first element can be composed of the ring element, the second element can be composed of the planetary carrier, and the third element can be composed of the sun element.

[0030] Alternatively, the first element can be composed of the sun element, the second element can be composed of the planetary carrier, and the third element can be composed of the ring element.

[0031] In the two-speed transmission according to an aspect of the present application, the sun element can be composed of a sun gear, the ring element can be composed of a ring gear, and the plurality of planetary elements can be composed of a plurality of planetary gears.

[0032] Alternatively, the sun element can be composed of a sun roller, the ring element can be composed of a ring roller, and the plurality of planetary elements can be composed of a plurality of planetary rollers. That is, the planetary reduction mechanism can be composed of a planetary friction roller reducer.

[0033] In the two-speed transmission according to an aspect of the present application, the transmission input element and / or the transmission output element can be composed of a gear.

[0034] The drive device for an electric vehicle according to an aspect of the present application includes a two-speed transmission having a transmission input element, and an electric motor configured to rotationally drive the transmission input element.

[0035] In particular, in the drive device for an electric vehicle according to an aspect of the present application, the two-speed transmission is composed of the two-speed transmission according to an aspect of the present application.

[0036] The drive device for an electric vehicle according to an aspect of the present application can further include a differential mechanism having a differential input element rotationally driven based on the rotation of the transmission output element, and configured to distribute the rotation input to the differential input element to a plurality of drive wheels.

[0037] Effects of the Invention

[0038] According to the two-speed transmission according to an aspect of the present application, it is possible to easily achieve the miniaturization of the drive device for an electric vehicle in which the two-speed transmission is incorporated. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a cross-sectional view schematically showing a first example of the drive device for an electric automobile of the embodiment of the present disclosure.

[0040] Figure 2 In (A), a graph showing a torque transmission path in a low reduction ratio mode, and (B) is a graph showing a torque transmission path in a high reduction ratio mode.

[0041] Figure 3 is a perspective view showing the first example of the drive device for an electric automobile.

[0042] Figure 4 is a side view showing the first example of the drive device for an electric automobile.

[0043] Figure 5 is a bottom view viewed from the lower side of Figure 4 .

[0044] Figure 6 is an end view viewed from the left side of Figure 4 .

[0045] Figure 7 is an A-A cross-sectional view of Figure 4 .

[0046] Figure 8 is a B-B cross-sectional view of Figure 4 .

[0047] Figure 9 is a C-C cross-sectional view of Figure 4 .

[0048] Figure 10 is a D-D cross-sectional view of Figure 4 .

[0049] Figure 11 In (A), a graph showing a torque transmission path in a low reduction ratio mode, and (B) is a graph showing a torque transmission path in a high reduction ratio mode. Figure 4 Figure 4

[0050] Figure 12 is a cross-sectional view schematically showing a second example of the drive device for an electric automobile of the embodiment of the present disclosure.

[0051] Figure 13 is a cross-sectional view schematically showing a third example of the drive device for an electric automobile of the embodiment of the present disclosure.

[0052] Figure 14 ​​is a cross-sectional view of a drive device for an electric automobile that schematically represents a fourth example of an embodiment of the present disclosure.

[0053] Figure 15 is a cross-sectional view of a drive device for an electric automobile that schematically represents a fifth example of an embodiment of the present disclosure.

[0054] Figure 16 is a chart for explaining an effect brought about by assembling a transmission with a drive device that uses an electric motor as a drive source.

[0055] In the drawings:

[0056] 1 - drive device for an electric automobile, 2, 2a - two-speed transmission, 3 - electric motor, 4 - differential mechanism, 5 - input gear (transmission input element), 6 - output gear (transmission output element), 7 - planetary gear reducer (planetary reduction mechanism), 8, 8a - first shift mechanism, 9, 9a - second shift mechanism, 10 - motor housing, 11 - motor output shaft, 12 - rotor, 13 - stator, 14 - drive gear, 15 - differential input element, 16a, 16b - drive shaft, 17 - input cylindrical portion, 18 - bearing, 19 - shaft member, 20 - sun gear (sun element), 21 - ring gear (ring element), 22 - carrier, 23 - planetary element (planetary gear), 23a - first planetary element (first planetary gear), 23b - second planetary element (second planetary gear), 24 - fixed portion, 25, 25a - sun shaft, 26 - main body portion, 27 - gear case, 28 - small-diameter cylindrical portion, 29 - large-diameter cylindrical portion, 30 - side plate portion, 31a, 31b - edge portion, 32 - connecting portion, 33 - side plate portion, 34, 34a - carrier cylindrical portion, 35 - support shaft, 36 - radial bearing, 37 - bearing, 38 - frictional engagement portion, 39 - elastic force applying unit, 40 - cam device, 41 - electric actuator, 42 - first friction plate, 43 - second friction plate, 44 - flange member, 45 - cylindrical portion, 46 - piston, 47 - elastic member, 48 - inner side circular ring portion, 49 - drive cam, 50 - driven cam, 51 - rolling body, 52 - fixed member, 53 - drive cam surface, 54 - support bearing, 55 - separation bearing, 56 - pressing member, 57a, 57b - race, 58 - rolling body, 59 - pre-pressing applying unit, 60 - worm, 61 - outer diameter side member, 62 - inner diameter side member, 63 - selection plate, 64 - outer side circular ring portion, 65 - pin, 66 - inner spline portion, 67 - reducer, 68 - circular ring portion, 69 - cylindrical portion, 70 - retainer, 71 - ring member. DETAILED DESCRIPTION

[0057] [First Example]

[0058] Using Figures 1-10A first example of an embodiment of the present disclosure will be described.

[0059] <Overall configuration of drive device for electric vehicle>

[0060] The drive device for electric vehicle 1 is provided with a two-speed transmission 2, an electric motor 3, and a differential mechanism 4. The drive device for electric vehicle 1 is configured to increase the output torque of the electric motor 3 by the two-speed transmission 2 and input the same to the differential mechanism 4, and distribute the same to a plurality of drive wheels by the differential mechanism 4.

[0061] However, the drive device for electric vehicle of the present embodiment can also be applied to a drive device not provided with a differential mechanism, i.e., a drive device in which the rotation of the transmission output element of the two-speed transmission is transmitted to the drive wheels without passing through the differential mechanism.

[0062] The two-speed transmission 2 is provided with a transmission input element 5, a transmission output element 6, a planetary reduction mechanism 7, a first shift mechanism 8, and a second shift mechanism 9. The two-speed transmission 2 is configured to switch the transmission path of the torque passing through the planetary reduction mechanism 7 by switching the mode of the first shift mechanism 8 and the mode of the second shift mechanism 9, and thereby switch the reduction ratio between the transmission input element 5 and the transmission output element 6 in two steps of high and low.

[0063] The electric motor 3 rotationally drives the transmission input element 5.

[0064] The electric motor 3 is provided with a motor housing 10, a motor output shaft 11, a rotor 12, and a stator 13.

[0065] The motor output shaft 11 is rotatably supported to the inside of the motor housing 10 via a plurality of bearings not shown.

[0066] The rotor 12 is fixedly fitted around the motor output shaft 11 in a manner to integrally rotate with the motor output shaft 11. The rotor 12 can adopt various configurations known at present such as a cage shape, a winding shape, a permanent magnet shape, and the like.

[0067] The stator 13 is disposed coaxially with the rotor 12 around the rotor 12 and is supported and fixed to the inside of the motor housing 10. Specifically, the inner peripheral surface of the stator 13 opposes the outer peripheral surface of the rotor 12 with a slight radial gap therebetween, and the outer peripheral surface of the stator 13 is fixedly fitted to the motor housing 10. The stator 13 can adopt various configurations known at present such as a winding shape, a permanent magnet shape, and the like.

[0068] The configuration for rotationally driving the transmission input element 5 by the electric motor 3 is not particularly limited, and the transmission input element 5 can be directly rotationally driven by the electric motor 3, or can be rotationally driven via a reducer.

[0069] In a case where the transmission input element 5 is directly rotationally driven by the electric motor 3, the transmission input element 5 can be directly formed or fixedly fitted to the motor output shaft 11.

[0070] In a case where the transmission input element 5 is rotationally driven by the electric motor 3 via a reduction gear, for example, a drive gear 14 provided to the motor output shaft 11 can be engaged with the transmission input element 5 composed of a gear directly or via one or more intermediate gears. Alternatively, a belt member can be spanned between a drive pulley provided to the motor output shaft 11 and the transmission input element 5 composed of a pulley. Alternatively, a chain can be spanned between a drive sprocket provided to the motor output shaft 11 and the transmission input element 5 composed of a sprocket.

[0071] In the present example, the drive gear 14 provided to the front end portion of the motor output shaft 11 is engaged with the transmission input element (input gear) 5 composed of a gear.

[0072] The drive gear 14 is not particularly limited as long as it can be engaged with the input gear 5 and transmit torque between the input gear 5. For example, the drive gear 14 is composed of a spur gear, a helical gear, or the like. In the present example, the drive gear 14 is composed of a helical gear.

[0073] The differential mechanism 4 has a differential input element 15 that is rotationally driven based on the rotation of the transmission output element 6, and distributes the rotation input to the differential input element 15 to a plurality of drive wheels.

[0074] The configuration of the differential mechanism 4 is not particularly limited as long as it can distribute the rotation input to the differential input element 15 to a plurality of drive wheels. Specifically, the differential mechanism 4 can be composed of an open differential that does not have a mechanism for limiting differential, or a differential that has a mechanism for limiting differential.

[0075] As the differential that has a mechanism for limiting differential, not limited to these, a differential lock mechanism that forcibly fixes the differential, a limited slip differential that can limit the differential according to a condition, and a torque vector differential that can independently control the torque to each drive wheel can be applied. In a case where the limited slip differential is applied as the differential mechanism 4, any one of a rotation sensing type that limits the differential according to a difference in rotational speed of the drive wheels, a torque sensing type that limits the differential according to a difference in torque of the drive wheels, and an electronic control type that controls the differential limitation by electronic control can be adopted.

[0076] In the present example, the differential mechanism 4 is composed of an open differential that distributes the rotation input to the differential input element 15 to a pair of drive shafts 16a, 16b that are connected to the drive wheels via constant velocity joints so as to be able to transmit torque.

[0077] The configuration for transmitting the rotation of the transmission output element 6 to the differential input element 15 is not particularly limited. For example, the transmission output element 6 composed of a gear can be directly or via one or more intermediate gears engaged with the differential input element 15 composed of a gear. Alternatively, a belt member can be spanned between the transmission output element 6 composed of a pulley and the differential input element 15 composed of a pulley. Alternatively, a chain can be spanned between the transmission output element 6 composed of a sprocket and the differential input element 15 composed of a sprocket.

[0078] In the present example, the transmission output element (output gear) 6 composed of a gear is directly engaged with the differential input element 15 composed of a gear.

[0079] <Detail Configuration of Two-Speed Transmission>

[0080] Hereinafter, the specific configuration of the two-speed transmission 2 will be described.

[0081] With respect to the two-speed transmission 2, the axial direction refers to the axial direction of the transmission input element 5 unless otherwise specified. The one-side side of the axial direction refers to the right side of Figure 1 , Figure 4 , Figure 5 and Figure 7 , and the other-side side of the axial direction refers to the left side of Figure 1 , Figure 4 , Figure 5 and Figure 7 .

[0082] The transmission input element 5 is rotatably supported to a fixed portion such as a housing that does not rotate in use. The transmission input element 5 is configured to be rotatably driven by the electric motor 3. Specifically, the transmission input element 5 is composed of a gear, a pulley, a sprocket, or the like. In the present example, the transmission input element 5 is composed of a gear (input gear).

[0083] The input gear 5 is not particularly limited as long as it can be engaged with the drive gear 14 rotatably driven by the electric motor 3 to transmit the torque therebetween. For example, the input gear 5 is composed of a spur gear, a helical gear, or the like. In the present example, the input gear 5 is composed of a helical gear.

[0084] In addition, the input gear (transmission input element) 5 has an input cylindrical portion 17 having a substantially cylindrical shape. In the present example, the input gear 5 is composed by providing a plurality of teeth on the outer circumferential surface of the input cylindrical portion 17.

[0085] The transmission output element 6 is supported coaxially with the transmission input element 5 and is capable of relative rotation with respect to the transmission input element 5. The transmission output element 6 has an outer diameter smaller than that of the transmission input element 5. In addition, the transmission output element 6 is configured to be capable of rotationally driving the differential input element 15 of the differential mechanism 4. Specifically, the transmission output element 6 is configured by a gear, a pulley, a sprocket, or the like. In this example, the transmission output element 6 is configured by a gear (output gear).

[0086] The output gear 6 is not particularly limited as long as it is capable of engaging with the differential input element 15 of the differential mechanism 4 and transmitting torque between the differential input element 15. For example, the output gear 6 is configured by a spur gear, a helical gear, or the like. In this example, the output gear 6 is configured by a helical gear.

[0087] In this example, the transmission output element (output gear) 6 is configured by providing a plurality of teeth on the outer circumferential surface of the axial member 19 that is rotatably supported to the above-described fixed portion by the bearing 18 and has a stepped cylindrical shape.

[0088] The planetary reduction mechanism 7 includes a sun element 20 supported coaxially with the transmission input element 5 and capable of relative rotation with respect to the transmission input element 5 and the transmission output element 6, a ring element 21 disposed coaxially with the sun element 20 around the sun element 20, a planet carrier 22 disposed coaxially with the sun element 20, and a plurality of planet elements 23 capable of transmitting torque and engaging with the sun element 20 and the ring element 21, in other words, transmitting torque between the sun element 20 and the ring element 21, and being rotatably supported to the planet carrier 22 with the respective center axes as centers.

[0089] The first element among the sun element 20, the ring element 21, and the planet carrier 22 is connected in a manner of integral rotation with respect to the transmission input element 5, and the second element other than the above-described first element among the sun element 20, the ring element 21, and the planet carrier 22 is connected in a manner of integral rotation with respect to the transmission output element 6.

[0090] The third element other than the above-described first element and the above-described second element among the sun element 20, the ring element 21, and the planet carrier 22 is provided with the first shift mechanism 8 between the above-described first element, and the fixed portion 24 that does not rotate at the time of use of the housing or the like is provided with the second shift mechanism 9 between the above-described third element.

[0091] The planetary reduction mechanism 7 is configured by a double-pinion type planetary reduction mechanism or a single-pinion type planetary reduction mechanism.

[0092] In the double-pinion type planetary reduction mechanism 7, the plurality of planetary elements 23 have a plurality of first planetary elements 23a that torque-transmissively engage with the sun element 20 and a plurality of second planetary elements 23b that torque-transmissively engage with the ring element 22 and torque-transmissively engage with the plurality of first planetary elements 23a.

[0093] In the case where the planetary reduction mechanism 7 is constituted by a double-pinion type planetary reduction mechanism, the above-described first element can be constituted by the carrier 22, the above-described second element can be constituted by the ring element 21, and the above-described third element can be constituted by the sun element 20. Alternatively, the above-described first element can be constituted by the sun element 20, the above-described second element can be constituted by the carrier 22, and the above-described third element can be constituted by the ring element 21.

[0094] In the single-pinion type planetary reduction mechanism 7, the plurality of planetary elements 23 torque-transmissively engage with both the sun element 20 and the ring element 21 respectively.

[0095] In the case where the planetary reduction mechanism 7 is constituted by a double-pinion type planetary reduction mechanism, the above-described first element can be constituted by the ring element 21, the above-described second element can be constituted by the carrier 22, and the above-described third element can be constituted by the sun element 20. Alternatively, the above-described first element can be constituted by the sun element 20, the above-described second element can be constituted by the carrier 22, and the above-described third element can be constituted by the ring element 21.

[0096] The planetary reduction mechanism 7 is constituted by a planetary gear reducer or a planetary friction roller reducer.

[0097] In the planetary gear reducer 7, the sun element 20, the ring element 22, and the plurality of planetary elements 23 are constituted by gears respectively, and torque transmission is performed by the meshing of the sun element (sun gear) 20 and the plurality of planetary elements (planetary gears) 23 and the meshing of the ring element (ring gear) 22 and the plurality of planetary elements (planetary gears) 23.

[0098] In the case where the planetary reduction mechanism 7 is constituted by a double-pinion type planetary gear reducer, the plurality of planetary gears 23 have a plurality of first planetary gears 23a that mesh with the sun gear 20 and a plurality of second planetary gears 23b that mesh with the ring gear 22 and mesh with the plurality of first planetary gears 23a.

[0099] In the case where the planetary reduction mechanism 7 is constituted by a single-pinion type planetary gear reducer, the plurality of planetary gears 23 mesh with both the sun gear 20 and the ring gear 22 respectively.

[0100] In the planetary friction roller decelerator 7, the sun element 20, the ring element 22, and the plurality of planetary elements 23 are each formed of a friction roller, and torque is transmitted through rolling contact of the sun element (sun roller) 20 and the plurality of planetary elements (planetary rollers) 23 and rolling contact of the ring element (ring roller) 22 and the plurality of planetary elements (planetary rollers) 23.

[0101] In a case where the planetary deceleration mechanism 7 is formed of a planetary friction roller decelerator of a double pinion type, the plurality of planetary rollers 23 have a plurality of first planetary rollers 23a that are in rolling contact with the sun roller 20 and a plurality of second planetary rollers 23b that are in rolling contact with the ring roller 22 and in rolling contact with the plurality of first planetary rollers 23a.

[0102] In a case where the planetary deceleration mechanism 7 is formed of a planetary friction roller decelerator of a single pinion type, the plurality of planetary rollers 23 are each in rolling contact with both the sun roller 20 and the ring roller 22.

[0103] In the present example, the planetary deceleration mechanism 7 is formed of a planetary gear decelerator of a double pinion type. Specifically, the planetary gear decelerator 7 has a sun gear 20, a ring gear 21, a planetary carrier 22, a plurality of first planetary gears 23a, and a plurality of second planetary gears 23b.

[0104] In addition, in the present example, a first element that is connected in an integrally rotatable manner with respect to the transmission input element (input gear) 5 is formed of the planetary carrier 22, a second element that is connected in an integrally rotatable manner with respect to the transmission output element (output gear) 6 is formed of the ring gear 21, and a third element is formed of the sun gear 20.

[0105] The sun gear 20 is disposed coaxially with the input gear 5 and is supported so as to be able to relatively rotate with respect to the input gear 5 and the output gear 6. The sun gear 20 is able to be switched by the first shift mechanism 8 between a cut-off mode in which relative rotation with respect to the planetary carrier 22 is possible and a connection mode in which relative rotation with respect to the planetary carrier 22 is not possible, and is able to be supported by the second shift mechanism 9 in a free mode in which rotation with respect to a fixed portion 24 that does not rotate in use, such as a housing, is possible and a lock mode in which rotation with respect to the fixed portion 24 is not possible.

[0106] In the present example, the sun gear 20 is formed by providing a plurality of teeth on an outer peripheral surface of an end portion on one side in an axial direction of a sun shaft 25 having a stepped cylindrical shape.

[0107] The ring gear 21 is disposed coaxially with the sun gear 20 around the sun gear 20 and is connected in an integrally rotatable manner with respect to the output gear 6.

[0108] In this example, the ring gear 21 has a main body portion 26 having a substantially cylindrical shape and a gear case 27 having a crank-shaped cross-sectional shape.

[0109] A plurality of teeth are provided on an inner peripheral surface of the main body portion 26 that opposes the sun gear 20.

[0110] The gear case 27 has a small-diameter cylindrical portion 28 on one axial side, a large-diameter cylindrical portion 29 on the other axial side, and a hollow circular plate portion 30 that connects the small-diameter cylindrical portion 28 and the large-diameter cylindrical portion 29. The main body portion 26 is fixedly fitted to the large-diameter cylindrical portion 29 so as not to rotate relative to each other, and an end portion of the shaft member 19 on the other axial side is fixedly fitted to the small-diameter cylindrical portion 28 so as not to rotate relative to each other. Thus, the output gear 6 and the ring gear 21 are connected so as to rotate as one.

[0111] The planetary carrier 22 is connected so as to rotate as one with respect to the input gear 5. The planetary carrier 22 supports a plurality of planetary gears 23 (23a, 23b) so as to be able to rotate (spin) about respective central axes of the plurality of planetary gears 23 and to rotate (orbit) about a central axis of the planetary carrier 22.

[0112] In this example, the planetary carrier 22 has a pair of edge portions 31a, 31b that are arranged apart in the axial direction and a plurality of connecting portions 32 that connect the pair of edge portions 31a, 31b to each other.

[0113] The edge portion 31a on one axial side of the pair of edge portions 31a, 31b has a hollow circular plate shape.

[0114] The edge portion 31b on the other axial side of the pair of edge portions 31a, 31b has a side plate portion 33 having a hollow circular plate shape and a planetary carrier cylindrical portion 34 that extends from an end portion on a radially outer side of the side plate portion 33 toward the other axial side and has a cylindrical shape. The input gear 5 (input cylindrical portion 17) is fixedly fitted to an end portion on the other axial side of the planetary carrier cylindrical portion 34 so as not to rotate relative to each other. Thus, the input gear 5 and the planetary carrier 22 are connected so as to rotate as one.

[0115] The plurality of connecting portions 32 connect a plurality of portions in the circumferential direction of an end portion on a radially outer side of the edge portion 31a on one axial side and a plurality of portions in the circumferential direction of a radially intermediate portion of the side plate portion 33 of the edge portion 31b on the other axial side in the axial direction.

[0116] The plurality of first planetary gears 23a and the plurality of second planetary gears 23b are rotatably supported by the planetary carrier 22 with their respective central axes parallel to the central axis of the planetary carrier 22, and are disposed at a plurality of positions in the circumferential direction between the sun gear 20 and the ring gear 21. The plurality of first planetary gears 23a are engaged with the sun gear 20. The plurality of second planetary gears 23b are engaged with the plurality of first planetary gears 23a and are engaged with the ring gear 21. That is, the plurality of first planetary gears 23a and the plurality of second planetary gears 23b are engaged with each other in pairs.

[0117] The number of first planetary gears 23a can be any number of two or more. Also, the number of second planetary gears 23b is the same as the number of first planetary gears 23a. In this example, the number of first planetary gears 23a is three. Therefore, the number of second planetary gears 23b is also three.

[0118] In this example, the plurality of first planetary gears 23a and the plurality of second planetary gears 23b are each formed by providing a plurality of teeth on the outer circumferential surface of a cylindrical body having a substantially cylindrical shape. The plurality of first planetary gears 23a and the plurality of second planetary gears 23b are each rotatably supported by the planetary carrier 22 with their respective central axes parallel to the central axis of the planetary carrier 22 via a support shaft 35 and a radial bearing 36.

[0119] The support shaft 35 is disposed with its central axis parallel to the central axis of the planetary carrier 22, and is supported in a cantilevered manner by the pair of edge portions 31a, 31b. Specifically, the end portion on the one axial side of the support shaft 35 is supported and fixed to the radially intermediate portion of the edge portion 31a on the one axial side, and the end portion on the other axial side of the support shaft 35 is supported and fixed to the radially intermediate portion of the side plate portion 33 of the edge portion 31b on the other axial side.

[0120] The radial bearing 36 is disposed between the inner circumferential surface of the first planetary gear 23a or the second planetary gear 23b and the outer circumferential surface of the support shaft 35. Thus, the plurality of first planetary gears 23a and the plurality of second planetary gears 23b are each rotatably supported around the support shaft 35 with their respective central axes parallel to the central axis of the support shaft 35.

[0121] The radial bearing 36 is formed of a radial rolling bearing having a plurality of rolling elements such as needles, or a radial rolling bearing having a cylindrical shape.

[0122] The planetary reduction mechanism (planetary gear reducer) 7 is disposed in the axial direction between the transmission input element (input gear) 5 and the transmission output element (output gear) 6. In other words, the transmission input element 5 is disposed on the other axial side of the planetary reduction mechanism 7, and the transmission output element 6 is disposed on the one axial side of the planetary reduction mechanism 7.

[0123] Therefore, in the two-speed transmission 2 according to the aspect of the present disclosure, for example, a bearing 37 or the like for rotatably supporting a motor housing 10 or a motor output shaft 11 of the electric motor 3 for rotationally driving the transmission input element 5 with respect to a fixed portion such as a housing can be arranged in proximity to the transmission output element 6 having an outer diameter smaller than that of the transmission input element 5. Therefore, the two-speed transmission 2 according to the aspect of the present disclosure can easily ensure the degree of freedom of the setting position of the electric motor 3, and easily achieve the miniaturization of the electric vehicle drive device 1 in which the two-speed transmission 2 is assembled, as compared with the configuration in which the output gear is arranged between the input gear and the planetary gear reducer and the electric motor is arranged in proximity to the input gear, as described in International Publication No. 2016 / 150411.

[0124] The first shift mechanism 8 is provided between the sun element (sun gear) 20 and the carrier 22, and switches between a cut mode in which the sun element 20 and the carrier 22 can relatively rotate and a connection mode in which the sun element 20 and the carrier 22 cannot relatively rotate. The first shift mechanism 8 has a not-shown actuator, and based on the operation of the actuator, switches between the cut mode in which the sun element 20 and the carrier 22 can relatively rotate and the connection mode in which the sun element 20 and the carrier 22 cannot relatively rotate.

[0125] The structure of the first shift mechanism 8 is not particularly limited as long as the first shift mechanism 8 can switch between the cut mode in which the sun element 20 and the carrier 22 can relatively rotate and the connection mode in which the sun element 20 and the carrier 22 cannot relatively rotate by the actuator. For example, the first shift mechanism 8 can be constituted by a clutch of an engagement type or a friction type, or the like.

[0126] The second shift mechanism 9 is provided between the fixed portion 24 that does not rotate at the time of use and the sun element (sun gear) 20, and switches between a free mode in which the sun element 20 can rotate with respect to the fixed portion 24 and a lock mode in which the sun element 20 cannot rotate with respect to the fixed portion 24. The second shift mechanism 9 has an actuator, and based on the operation of the actuator, switches between the free mode in which the sun element 20 can rotate with respect to the fixed portion 24 and the lock mode in which the sun element 20 cannot rotate with respect to the fixed portion 24.

[0127] The structure of the second shift mechanism 9 is not particularly limited as long as the second shift mechanism 9 can switch between the free mode in which the sun element 20 can rotate with respect to the fixed portion 24 and the lock mode in which the sun element 20 cannot rotate with respect to the fixed portion 24 by the actuator. For example, the second shift mechanism 9 can be constituted by a brake of an engagement type or a friction type, or the like. Alternatively, the second shift mechanism 9 can also be constituted by a brake (torque selection device) that has, in addition to the free mode and the lock mode, a one-way clutch mode that allows rotation of the sun element 20 in a predetermined direction and prevents rotation in the direction opposite to the predetermined direction.

[0128] As the actuators that constitute the first shift mechanism 8 and the second shift mechanism 9, electric actuators such as electric motors, solenoids, hydraulic cylinders that operate using hydraulic pressure, and the like can be used. However, in an electric vehicle, in order to remove or downsize a hydraulic system to achieve cost reduction and / or power consumption performance improvement due to system simplification, it is preferable to use an electric actuator as the actuator that constitutes the second shift mechanism 9.

[0129] The actuators that constitute the first shift mechanism 8 and the second shift mechanism 9 can be constituted by the same actuator or by different actuators.

[0130] In the two-speed transmission 2, at least a portion of the first shift mechanism 8 and / or the second shift mechanism 9 is disposed radially inward of the input cylinder portion 17.

[0131] In the present example, the axially other-side portion of the second shift mechanism 9 is disposed radially inward of the input cylinder portion 17. In other words, the input cylinder portion 17 is disposed radially outward of the axially other-side portion of the second shift mechanism 9.

[0132] More specifically, the first shift mechanism 8 is disposed radially inward of the axially one-side portion of the planetary carrier cylinder portion 34, between the axially one-side portion of the planetary carrier cylinder portion 34 and the axially intermediate portion of the sun shaft 25. The second shift mechanism 9 is disposed radially inward of the axially other-side portion of the planetary carrier cylinder portion 34, between the axially other-side portion of the planetary carrier cylinder portion 34 and the fixed portion 24. The input cylinder portion 17 is fitted and fixed to the end portion of the axially other-side of the planetary carrier cylinder portion 34. Thereby, the axially other-side portion of the second shift mechanism 9 is disposed radially inward of the input cylinder portion 17.

[0133] In the case of implementing the two-speed transmission according to an aspect of the present disclosure, as shown in Figure 11 (A), the input cylinder portion 17 can also be fitted and fixed to the axially intermediate portion of the planetary carrier cylinder portion 34. In this case, the axially other-side portion of the first shift mechanism 8 and the axially one-side portion of the second shift mechanism 9 are disposed radially inward of the input cylinder portion 17.

[0134] Alternatively, as shown in Figure 11 (B), the input cylinder portion 17 can also be fitted and fixed to the end portion of the axially one-side of the planetary carrier cylinder portion 34. In this case, the axially one-side portion of the first shift mechanism 8 is disposed radially inward of the input cylinder portion 17.

[0135] In the two-speed transmission 2 according to the aspect of the present disclosure, at least a part of the first shift mechanism 8 and / or the second shift mechanism 9 is arranged radially inward of the input cylinder portion 17. Therefore, the two-speed transmission 2 according to the aspect of the present disclosure can suppress the axial dimension and can easily achieve miniaturization, as compared to a configuration in which the input gear, the output gear, the planetary gear reducer, the first shift mechanism, and the second shift mechanism are arranged in series in the axial direction, as described in International Publication No. 2016 / 150411.

[0136] In this example, the entire first shift mechanism 8 and the entire second shift mechanism 9 are arranged radially inward of the planetary carrier cylinder portion 34.

[0137] However, if at least a part of the first shift mechanism 8 and / or the second shift mechanism 9 is arranged radially inward of the input cylinder portion 17, it is also possible to arrange a part of the first shift mechanism 8 and / or the second shift mechanism 9 at a position separated in the axial direction from the planetary carrier cylinder portion 34 radially inward thereof. For example, in Figure 11 (A) or the second modification example shown in Figure 11 (B), it is possible to configure so as to omit a part of the planetary carrier cylinder portion 34 that protrudes toward the other side in the axial direction from the input cylinder portion 17.

[0138] In a case where a part of the first shift mechanism 8 and / or the second shift mechanism 9 is arranged at a position separated in the axial direction from the planetary carrier cylinder portion 34 radially inward thereof, it is possible to make the outer diameter of the part arranged at the position separated in the axial direction from the planetary carrier cylinder portion 34 radially inward thereof larger than the inner diameter of the planetary carrier cylinder portion 34.

[0139] The two-speed transmission 2 can switch between a low reduction ratio mode in which the reduction ratio between the transmission input element (input gear) 5 and the transmission output element (output gear) 6 is small (the reduction ratio is 1) and a high reduction ratio mode in which the reduction ratio is larger than in the low reduction ratio mode, by switching the mode of the first shift mechanism 8 and the mode of the second shift mechanism 9.

[0140] (Low reduction ratio mode)

[0141] In order to switch the two-speed transmission 2 to the low reduction ratio mode, the first shift mechanism 8 is switched to the connected mode in which the sun element (sun gear) 20 and the planetary carrier 22 cannot rotate relative to each other, and the second shift mechanism 9 is switched to the free mode in which the sun element (sun gear) 20 can rotate relative to the fixed portion 24. Thereby, the sun element (sun gear) 20 and the planetary carrier 22 rotate as a unit, and the rotation of the sun element (sun gear) 20 relative to the fixed portion 24 is allowed.

[0142] In such a low reduction ratio mode, the rotation directions and rotational speeds of the sun element (sun gear) 20, the ring element (ring gear) 21, and the planet carrier 22 are the same, and the so-called "synchronized state" in which the entire planetary reduction mechanism (planetary gear reducer) 7 rotates as a whole is established. Therefore, the rotation input from the electric motor 3 to the transmission input element (input gear) 5 via the drive gear 14 is transmitted to the transmission output element (output gear) 6 via the path shown by the thick line in (A) without being reduced. Figure 2 (A) In the low reduction ratio mode, the reduction ratio between the transmission input element (input gear) 5 and the transmission output element (output gear) 6 is 1.

[0143] (High reduction ratio mode)

[0144] To switch the two-speed transmission 2 to the high reduction ratio mode, the first shift mechanism 8 is switched to the cut-off mode in which the sun element (sun gear) 20 and the planet carrier 22 can relatively rotate, and the second shift mechanism 9 is switched to the lock mode in which the sun element (sun gear) 20 cannot rotate with respect to the fixed portion 24. Thus, the sun element (sun gear) 20 and the planet carrier 22 can relatively rotate, and the rotation of the sun element (sun gear) 20 with respect to the fixed portion 24 is prevented.

[0145] In such a high reduction ratio mode, the rotation input from the electric motor 3 to the transmission input element (input gear) 5 via the drive gear 14 is transmitted to the transmission output element (output gear) 6 via the path shown by the thick line in (B) after being reduced. Figure 2 (B) In the low reduction ratio mode, the reduction ratio between the transmission input element (input gear) 5 and the transmission output element (output gear) 6 is 1.

[0146] The reduction ratio between the transmission input element 5 and the transmission output element 6 in the high reduction ratio mode is determined by the gear ratio of the ring element 21 and the sun element 20. In this example, the reduction ratio between the input gear 5 and the output gear 6 is determined by the number of teeth of the sun gear 20 with respect to the number of teeth of the ring gear 21 (number of teeth of the ring gear 21 / number of teeth of the sun gear 20).

[0147] The two-speed transmission 2 is capable of switching the reduction ratio between the transmission input element 5 and the transmission output element 6 in two stages. Specifically, in a region where the rotation input to the transmission input element 5 from the electric motor 3 via the drive gear 14 is low speed and high torque, the two-speed transmission 2 is switched to a high reduction ratio mode, and in a region where the rotation input to the transmission input element 5 is high speed and low torque, the two-speed transmission 2 is switched to a low reduction ratio mode. Thus, in an electric vehicle that uses only the electric motor 3 as a drive source, it is possible to bring the acceleration performance and the high speed performance close to those of a gasoline engine vehicle.

[0148] [Second Example]

[0149] Use Figure 12 A second example of an embodiment of the present disclosure will be described. In this example, the same reference signs are attached to the constituent elements having the same functions as those of the first example, and detailed description will be omitted.

[0150] In this example, the first shift mechanism 8a is constituted by a friction clutch of the normally open type, and the second shift mechanism 9a is constituted by an engagement type brake.

[0151] The first shift mechanism 8a is provided with a friction engagement portion 38, an elastic force applying unit 39, a cam device 40, and an electric actuator 41.

[0152] The friction engagement portion 38 has at least one first friction plate 42 and at least one second friction plate 43 that are supported so as to be able to undergo relative displacement in the axial direction, and is provided between the sun gear 20 and the carrier 22. The friction engagement portion 38 is switched to a connection mode in which the sun gear 20 and the carrier 22 rotate as one by pressing and abutting the first friction plate 42 and the second friction plate 43 against each other. In contrast, when the force pressing and abutting the first friction plate 42 and the second friction plate 43 against each other is released, the friction engagement portion 38 is switched to a cut mode in which the sun gear 20 and the carrier 22 are able to rotate relatively.

[0153] In this example, the friction engagement portion 38 has a plurality of first friction plates 42 and a plurality of second friction plates 43. The friction engagement portion 38 is constituted by a multi-plate clutch in which the plurality of first friction plates 42 that are supported so as to be able to undergo relative displacement in the axial direction with respect to the sun gear 20 and the plurality of second friction plates 43 that are supported so as to be able to undergo relative displacement in the axial direction with respect to the carrier 22 are alternately overlapped. A not-shown return spring that elastically applies a force in a direction in which the interval of the first friction plate 42 and the second friction plate 43 is expanded is provided between the first friction plate 42 and the second friction plate 43. The elastic force of the return spring is smaller than the elastic restoring force of the elastic member 47 of the elastic force applying unit 39.

[0154] The plurality of first friction plates 42 are supported so as to be axially displaceable and non-rotatable relative to the outer circumferential surface of the cylindrical portion 45 of the flange member 44 having a crank-shaped cross-sectional shape which is fixed so as to be non-axially displaceable and non-rotatable relative to the sun shaft 25a.

[0155] The plurality of second friction plates 43 are supported so as to be axially displaceable and non-rotatable relative to the inner circumferential surface of the axially other side portion of the planetary carrier cylindrical portion 34a.

[0156] The elastic force applying unit 39 elastically applies a force in a direction in which the first friction plates 42 and the second friction plates 43 are pressed against each other. In the present example, the elastic force applying unit 39 has a piston 46 and an elastic member 47.

[0157] The piston 46 is supported so as to be axially displaceable relative to the sun shaft 25a. In the present example, the piston 46 has a circular ring portion 68 which is externally fitted so as to be axially displaceable relative to the sun shaft 25a, and a cylindrical portion 69 which is elongated from the radially outer end portion of the circular ring portion 68 toward the axially other side. The cylindrical portion 69 has an axially other side end surface which opposes the axially one side surface of the first friction plate 42 which is located on the axially most one side among the plurality of first friction plates 42.

[0158] The elastic member 47 is provided between the sun shaft 25a and the piston 46. In the present example, the elastic member 47 is externally fitted to the sun shaft 25a, and is held in an elastically compressed state between a ring-shaped member 71 whose displacement toward the axially one side is prevented by a stopper 70 and the axially one side surface of the piston 46. That is, the elastic force applying unit 39 presses the first friction plate 42 which is located on the axially most one side toward the axially other side via the piston 46 by the force with which the elastic member 47 elastically returns, and thereby elastically applies a force in a direction in which the first friction plates 42 and the second friction plates 43 are pressed against each other.

[0159] The elastic member 47 is constituted by a disc spring, a compression coil spring, a tension coil spring, or the like. The elastic member 47 can be constituted by one spring, or can be constituted by a plurality of springs. In the present example, the elastic member 47 is constituted by two disc springs which are reversely overlapped in the axial direction in a two-stage series combination such that the radially large end portions thereof oppose each other.

[0160] The cam device 40 has a drive cam 49, a driven cam 50, and a plurality of rolling bodies 51. The cam device 40 presses the elastic force applying unit 39 in a direction in which the force with which the first friction plates 42 and the second friction plates 43 are pressed against each other is released, based on the movement of the driven cam 50 in a direction in which the axial spacing from the drive cam 49 is enlarged, with the rotation of the drive cam 49.

[0161] The drive cam 49 is supported by a support bearing 54 so as to be relatively rotatable and relatively displaceable in the axial direction with respect to a fixed member 52 supported by a fixed portion which does not rotate and is not displaced in the housing or the like in use. The drive cam 49 has a drive cam surface 53 in which concave portions and convex portions are alternately arranged in the circumferential direction in equal numbers in a radially inner portion of a side surface on one axial side. The drive cam 49 is configured to be rotatably driven by the electric actuator 41.

[0162] The driven cam 50 is arranged so as to be relatively displaceable in the axial direction with respect to the fixed member 52 around the fixed member 52. Specifically, the driven cam 50 is supported so as to be relatively displaceable in the axial direction with respect to the fixed member 52 by making an inner spline portion 66 provided on an inner peripheral surface of the driven cam 50 and an outer spline portion 67 provided on an outer peripheral surface of an axial one side portion of the fixed member 52 in spline engagement.

[0163] The driven cam 50 opposes the piston 46 of the elastic force applying unit 39 with the separation bearing 55 and the pressing member 56 interposed therebetween. In other words, the separation bearing 55 and the pressing member 56 are provided between the driven cam 50 and the elastic force applying unit 39.

[0164] The separation bearing 55 is provided between the pressing member 56 opposing the piston 46 of the elastic force applying unit 39 and the driven cam 50 of the cam device 40. The separation bearing 55 has a pair of raceway rings 57a, 57b and a plurality of rolling bodies 58 which are arranged so as to be freely rotatable between the pair of raceway rings 57a, 57b. The raceway ring 57b on the other axial side of the pair of raceway rings 57a, 57b supports the driven cam 50.

[0165] In this example, a pre-press applying unit 59 for applying a pre-press to the separation bearing 55 is provided between the separation bearing 55 and the sun shaft 25a. The pre-press applying unit 59 is sandwiched between an axial one side surface of the raceway ring 57a on the one axial side of the pair of raceway rings 57a, 57b constituting the separation bearing 55 and an axial other side surface of the inner side annular portion 48 of the flange member 44 in an elastically compressed state. Thus, even in a state in which the piston 46 is pressed toward the one axial side against the elastic restoring force of the elastic member 47, a pre-press is applied to the separation bearing 55, and the separation bearing 55 is prevented from falling out of between the elastic force applying unit 39 and the cam device 40. The elastic force of the pre-press applying unit 59 is smaller than the elastic restoring force of the elastic member 47. The pre-press applying unit 59 can be constituted by one to a plurality of disc springs or one to a plurality of coil springs, for example.

[0166] The pressing member 56 has a cylindrical base portion and a protruding portion protruding from the circumferential direction of the end portion of the base portion on the one axial side. The one axial side race 57a of the pair of races 57a, 57b of the release bearing 55 is supported and fixed to the end portion of the base portion on the other axial side. The protruding portion is inserted into the through hole provided in the inner circular ring portion 48 of the flange member 44, and the front end portion (the end portion on the one axial side) of the protruding portion opposes the radially intermediate portion of the other axial side surface of the piston 46.

[0167] The plurality of rolling bodies 51 are respectively supported to the driven cam 50 so as to be able to rotate (rotate on their own axes) about their own axes (axes of rotation) in the radial direction centered on the axis of the driven cam 50. The plurality of rolling bodies 51 respectively roll in contact with the driven cam surface 53 of the drive cam 49.

[0168] In the cam device 40, as the drive cam 49 rotates, the climbing amount of the rolling bodies 51 from the bottoms of the recesses constituting the driven cam surface 53 increases and decreases, and the driven cam 50 moves in the axial direction.

[0169] That is, when the drive cam 49 is caused to rotate in a predetermined direction, the climbing amount of the rolling bodies 51 from the bottoms of the recesses constituting the driven cam surface 53 increases, and the driven cam 50 moves in the one axial side direction. When the driven cam 50 moves in the one axial side direction, the piston 46 of the elastic force applying unit 39 is pressed in the one axial side direction via the release bearing 55 and the pressing member 56, and the elastic member 47 is elastically compressed. Thus, the force pressing the first friction plate 42 and the second friction plate 43 against each other decreases, and eventually lost. Also, the interval between the first friction plate 42 and the second friction plate 43 expands by the action of the return spring, and thus switched to the cut mode in which the relative rotation of the sun gear 20 and the planet carrier 22 is enabled.

[0170] On the contrary, when the drive cam 49 is caused to rotate in the direction opposite to the predetermined direction, the climbing amount of the rolling bodies 51 from the bottoms of the recesses constituting the driven cam surface 53 decreases, and the driven cam 50 moves in the other axial side direction. When the driven cam 50 moves in the other axial side direction, the force pressing the piston 46 of the elastic force applying unit 39 in the one axial side direction via the release bearing 55 and the pressing member 56 decreases. When the force pressing the piston 46 in the one axial side direction decreases, the piston 46, the release bearing 55, and the pressing member 56 are pressed in the other axial side direction mainly by the elastic restoring force of the elastic member 47, and the second friction plate 43 on the one axial side is pressed in the other axial side direction by the piston 46. Thus, the first friction plate 42 and the second friction plate 43 are pressed against each other, and switched to the connected mode in which the relative rotation of the sun gear 20 and the planet carrier 22 is disabled.

[0171] The electric actuator 41 has a shift motor and a speed reducer 67, and the driving cam 49 of the cam device 40 is rotationally driven via the speed reducer 67 by the shift motor. In this example, the speed reducer 67 is configured by engaging a worm gear tooth provided on the outer circumferential surface of a worm 60 rotationally driven by the shift motor with a worm wheel tooth provided on the outer circumferential surface of the driving cam 49.

[0172] The second shift mechanism 9a has an outer diameter side member 61, an inner diameter side member 62, a not-shown engagement pin, and a selection plate 63.

[0173] The outer diameter side member 61 has a substantially cylindrical shape, and is supported and fixed with respect to a fixed portion that does not rotate nor displace in use.

[0174] The inner diameter side member 62 has a substantially cylindrical shape, and is fixedly fitted in a non-rotatable manner to an outer side ring portion 64 that extends toward the radial outer side from the end portion on the other axial side of the cylindrical portion 45 in the flange member 44. Thus, the inner diameter side member 62 rotates integrally with the sun gear 20.

[0175] The engagement pin is erected between the outer diameter side member 61 and the inner diameter side member 62 in a detachable manner. Specifically, for example, the engagement pin protrudes toward the radial inner side from the inner circumferential surface of the outer diameter side member 61, and is supported in a state in which a spring force toward the radial inner side is applied. The inner diameter side member 62 has an engagement recess portion that can engage the leading end portion of the engagement pin on the outer circumferential surface.

[0176] The selection plate 63 has a mode selection portion as a concave-convex portion in the circumferential direction. A plurality of pins 65 are erected between the selection plate 63 and the driving cam 49. Thus, the driving cam 49 and the selection plate 63 rotate integrally (in the same direction at the same speed).

[0177] The second shift mechanism 9a switches between a state in which the outer diameter side member 61 and the inner diameter side member 62 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 63. That is, based on rotating the selection plate 63, the engagement pin is pushed upward toward the radial outer side by the convex portion that constitutes the mode selection portion, and thus the engagement between the engagement pin and the engagement recess portion is released. Thus, the rotation of the inner diameter side member 62 relative to the outer diameter side member 61 is allowed, and the rotation of the sun gear 20 relative to the fixed portion is allowed. In contrast, based on rotating the selection plate 63, the convex portion that constitutes the mode selection portion is moved to a position that is deviated in the circumferential direction from the leading end portion of the engagement pin, and thus the engagement between the engagement pin and the engagement recess portion is engaged. Thus, the rotation of the inner diameter side member 62 relative to the outer diameter side member 61 is prevented, and the rotation of the sun gear 20 relative to the fixed portion is prevented.

[0178] In the two-speed transmission 2a of the present example, a part of the first shift mechanism 8a is arranged radially inward of the input cylinder portion 17. Specifically, the axially one side portion of the first shift mechanism 8a is arranged radially inward of the planetary carrier cylinder portion 34a. More specifically, the frictional engagement portion 38, the elastic force applying unit 39, the pressing member 56, and the pre-press applying unit 59 in the first shift mechanism 8a are arranged radially inward of the planetary carrier cylinder portion 34a. The input cylinder portion 17 is fixedly fitted to the end portion of the axially one side of the planetary carrier cylinder portion 34a. Thus, the elastic force applying unit 39 of the first shift mechanism 8a is arranged radially inward of the input cylinder portion 17.

[0179] In the case of the present example, a part of the first shift mechanism 8a is also arranged radially inward of the input cylinder portion 17, and thus, the axial dimension can be suppressed, and miniaturization can be easily achieved.

[0180] In the present example, the axially other side portion of the first shift mechanism 8a and the second shift mechanism 9a are arranged at positions axially deviated from the planetary carrier cylinder portion 34a radially inward. In addition, the outer diameter of the axially other side portion of the first shift mechanism 8a is larger than the inner diameter of the planetary carrier cylinder portion 34a, and the outer diameter of the second shift mechanism 9a is larger than the inner diameter of the planetary carrier cylinder portion 34a.

[0181] In the two-speed transmission 2a of the present example, the driving cam 49 is rotationally driven by one shift motor, and by adjusting the circumferential direction phase of the driving cam 49, the mode of the first shift mechanism 8a can be switched, and by adjusting the circumferential direction phase of the selection plate 63, the mode of the second shift mechanism 9a can be switched.

[0182] The structures and effects of the other portions of the second example are the same as those of the first example.

[0183] [Third Example]

[0184] Use Figure 13 A third example of an embodiment of the present disclosure will be described. In the present example, the same reference signs are attached to the constituent elements having the same functions as those of the first example, and detailed description will be omitted.

[0185] In the present example, the planetary reduction mechanism 7 is constituted by a double pinion type planetary reduction mechanism.

[0186] In addition, the first element connected in a manner of integrally rotating with respect to the transmission input element 5 is constituted by the sun element 20, the second element connected in a manner of integrally rotating with respect to the transmission output element 6 is constituted by the ring element 21, and the third element is constituted by the planetary carrier 22. That is, the first shift mechanism 8 is provided between the sun element 20 and the planetary carrier 22, and the second shift mechanism 9 is provided between the fixed portion 24 and the planetary carrier 22.

[0187] In the two-speed transmission 2 of the present example, by switching the mode of the first shift mechanism 8 and the mode of the second shift mechanism 9, it is also possible to switch the reduction ratio between the transmission input element 5 and the transmission output element 6 in two steps of high and low.

[0188] In order to switch the two-speed transmission 2 to the low reduction ratio mode, the first shift mechanism 8 is switched to the connected mode in which the sun element 20 and the carrier 22 cannot rotate relative to each other, and the second shift mechanism 9 is switched to the free mode in which the carrier 22 can rotate relative to the fixed portion 24.

[0189] In the low reduction ratio mode, the rotation directions and rotational speeds of the sun element 20, the ring element 21, and the carrier 22 become the same, and the planetary reduction mechanism 7 as a whole rotates in the so-called locked state. As a result, the rotation input to the transmission input element 5 is transmitted without reduction to the transmission output element 6.

[0190] In order to switch the two-speed transmission 2 to the high reduction ratio mode, the first shift mechanism 8 is switched to the disconnected mode in which the sun element 20 and the carrier 22 can rotate relative to each other, and the second shift mechanism 9 is switched to the locked mode in which the carrier 22 cannot rotate relative to the fixed portion 24.

[0191] In the high reduction ratio mode, the rotation input to the transmission input element 5 is transmitted in the order of the rotational movement of the sun element 20, the rotational movement of the first planetary element 23a, the rotational movement of the second planetary element 23b, the rotational movement of the ring element 21, and the rotational movement of the transmission output element 6.

[0192] The configurations and effects of the other portions of the third example are the same as those of the first example.

[0193] [Fourth Example]

[0194] Use Figure 14 A fourth example of an embodiment of the present disclosure will be described. In the present example, the same reference signs are attached to the configuration elements having the same functions as those of the first example, and detailed description will be omitted.

[0195] In the present example, the planetary reduction mechanism 7 is configured by a single pinion type planetary reduction mechanism. That is, the plurality of planetary rollers 23 configuring the planetary reduction mechanism 7 are each engaged with both the sun roller 20 and the ring roller 22 so as to transmit torque.

[0196] Furthermore, the first element connected so as to rotate integrally with the transmission input element 5 is constituted by the ring element 21, the second element connected so as to rotate integrally with the transmission output element 6 is constituted by the planetary carrier 22, and the third element is constituted by the sun element 20. Specifically, the first shift mechanism 8 is interposed between the ring element 21 and the sun element 20, and the second shift mechanism 9 is interposed between the fixed portion 24 and the sun element 20.

[0197] In the two-speed transmission 2 of this example, the reduction ratio between the transmission input element 5 and the transmission output element 6 can be switched between high and low levels by switching the modes of the first shift mechanism 8 and the second shift mechanism 9 .

[0198] In order to switch the two-speed transmission 2 to the low reduction ratio mode, the first shift mechanism 8 is switched to a connection mode in which the ring element 21 and the sun element 20 cannot rotate relative to each other, and the second shift mechanism 9 is switched to a free mode in which the sun element 20 can rotate relative to the fixed part 24.

[0199] In the low reduction ratio mode, the sun element 20, ring element 21, and planetary carrier 22 rotate in the same direction and at the same speed, creating a so-called "sizing" state in which the entire planetary reduction mechanism 7 rotates as one. As a result, the rotation input to the transmission input element 5 is transmitted to the transmission output element 6 without being reduced in speed.

[0200] In order to switch the two-speed transmission 2 to the high reduction ratio mode, the first shift mechanism 8 is switched to the cut-off mode in which the ring element 21 and the sun element 20 can rotate relative to each other, and the second shift mechanism 9 is switched to the lock mode in which the sun element 20 cannot rotate relative to the fixed part 24.

[0201] In the high reduction ratio mode, the rotation input to the transmission input element 5 is transmitted in the order of the rotational motion of the ring element 21, the rotational motion of the planetary element 23, the revolution motion of the planetary element 23 based on the engagement with the sun element 20, the rotational motion of the planetary carrier 22, and the rotational motion of the transmission output element 6.

[0202] The structure and effects of other parts of the fourth example are the same as those of the first example.

[0203] [Fifth example]

[0204] use Figure 15 A fifth example of the embodiment of the present disclosure will be described. In this example, components having the same functions as those of the first example are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0205] In this example, the planetary reduction mechanism 7 is composed of a single pinion type planetary reduction mechanism.

[0206] Further, a first element connected in an integral rotation with respect to the transmission input element 5 is constituted by the sun element 20, a second element connected in an integral rotation with respect to the transmission output element 6 is constituted by the carrier 22, and a third element is constituted by the ring element 21. That is, the first shift mechanism 8 is provided between the sun element 20 and the ring element 21, and the second shift mechanism 9 is provided between the fixed portion 24 and the ring element 21.

[0207] In the two-speed transmission 2 of the present example, by switching the mode of the first shift mechanism 8 and the mode of the second shift mechanism 9, it is also possible to switch the reduction ratio between the transmission input element 5 and the transmission output element 6 in two steps of high and low.

[0208] In order to switch the two-speed transmission 2 to the low reduction ratio mode, the first shift mechanism 8 is switched to a connected mode in which the sun element 20 and the ring element 21 cannot rotate relative to each other, and the second shift mechanism 9 is switched to a free mode in which the ring element 21 can rotate relative to the fixed portion 24.

[0209] In the low reduction ratio mode, the sun element 20, the ring element 21, and the carrier 22 rotate in the same direction and at the same speed, and the entire planetary reduction mechanism 7 becomes a so-called primed state in which it rotates as a whole. As a result, the rotation input to the transmission input element 5 is transmitted without reduction to the transmission output element 6.

[0210] In order to switch the two-speed transmission 2 to the high reduction ratio mode, the first shift mechanism 8 is switched to a disconnected mode in which the sun element 20 and the ring element 21 can rotate relative to each other, and the second shift mechanism 9 is switched to a locked mode in which the ring element 21 cannot rotate relative to the fixed portion 24.

[0211] In the high reduction ratio mode, the rotation input to the transmission input element 5 is transmitted in the order of the rotational movement of the sun element 20, the rotational movement of the planetary element 23, the translational movement of the planetary element 23 based on engagement with the ring element 21, the rotational movement of the carrier 22, and the rotational movement of the transmission output element 6.

[0212] The configurations and effects of the other parts of the fifth example are the same as those of the first example and the fourth example.

Claims

1. A two-speed transmission characterized by, Possessing: a transmission input element which is supported so as to be rotatable; a transmission output element which is supported so as to be coaxial with the transmission input element and so as to be capable of relative rotation with respect to the transmission input element; a planetary reduction mechanism which has a sun element which is supported so as to be coaxial with the transmission input element and so as to be capable of relative rotation with respect to the transmission input element and the transmission output element, a ring element which is disposed coaxially around the sun element, a planet carrier which is disposed coaxially with the sun element, and a plurality of planet elements which are torque-transmissively engaged with the sun element and the ring element and are rotatably supported on the planet carrier with their respective central axes as centers, a first one of the sun element, the ring element, and the planet carrier being connected to the transmission input element in an integrally rotatable manner, a second one of the sun element, the ring element, and the planet carrier being connected to the transmission output element in an integrally rotatable manner; a first shift mechanism which is provided between the first one and a third one of the sun element, the ring element, and the planet carrier and which switches between a disconnected mode in which the first one and the third one are capable of relative rotation and a connected mode in which the first one and the third one are incapable of relative rotation; and a second shift mechanism which is provided between a stationary portion which does not rotate in use and the third one and which switches between a free mode in which the third one is capable of rotation with respect to the stationary portion and a locked mode in which the third one is incapable of rotation with respect to the stationary portion, the planetary reduction mechanism being disposed between the transmission input element and the transmission output element in the axial direction of the transmission input element.

2. The two-speed transmission according to claim 1, characterized in that the transmission input element has an input cylinder portion, at least a portion of the first shift mechanism and / or the second shift mechanism is disposed radially inward of the input cylinder portion.

3. The two-speed transmission according to claim 1 or 2, characterized in that the plurality of planet elements have a plurality of first planet elements which are torque-transmissively engaged with the sun element and a plurality of second planet elements which are torque-transmissively engaged with the ring element and the plurality of first planet elements.

4. The two-speed transmission according to claim 3, characterized in that the first one is constituted by the planet carrier, the second one is constituted by the ring element, and the third one is constituted by the sun element.

5. The two-speed transmission according to claim 3, characterized in that the first one is constituted by the sun element, the second one is constituted by the ring element, and the third one is constituted by the planet carrier.

6. The two-speed transmission according to claim 1 or 2, characterized in that the plurality of planet elements are each torque-transmissively engaged with both the sun element and the ring element.

7. The two-speed transmission according to claim 6, characterized in that ​ The first element is composed of the ring element, the second element is composed of the carrier, and the third element is composed of the sun element.

8. The two-speed transmission according to claim 6, characterized in that, The first element is composed of the sun element, the second element is composed of the carrier, and the third element is composed of the ring element.

9. The two-speed transmission according to any one of claims 1 to 8, characterized in that, The sun element is composed of a sun gear, the ring element is composed of a ring gear, and the plurality of planetary elements are composed of a plurality of planetary gears.

10. The two-speed transmission according to any one of claims 1 to 9, characterized in that, The transmission input element and / or the transmission output element is composed of a gear.

11. An electric vehicle drive device characterized by comprising: Possessing: a two-speed transmission having a transmission input element; and an electric motor for rotationally driving the transmission input element, The two-speed transmission is composed of the two-speed transmission according to any one of claims 1 to 10.

12. The electric vehicle drive device according to claim 11, characterized in that, Further possessing a differential mechanism having a differential input element rotationally driven based on the rotation of the transmission output element, and distributing the rotation input to the differential input element to a plurality of drive wheels.

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