Unit

Abstract

[Problem] To reduce the gear ratio during gear shifting in a unit having an internal power transmission mechanism. [Solution] A unit has an input element, an output element, first to third engaging elements, a first planetary gear mechanism in which first to third rotating elements are arranged in this order on a collinear diagram, and a second planetary gear mechanism in which fourth to sixth rotating elements are arranged in this order on the collinear diagram. The input element is connected to the first rotating element and the sixth rotating element, the output element is connected to the second rotating element, one side of the first engaging element is connected to the third rotating element and the fifth rotating element, the other side of the first engaging element is fixed, one side of the second engaging element is connected to the fourth rotating element, the other side of the second engaging element is fixed, and the third engaging element connects two rotating elements that are selected from the first to sixth rotating elements and are not connected to each other.

Description

Technical Field

[0001] The present invention relates to a unit having a power transmission mechanism therein.

Background Art

[0002] Patent Document 1 discloses an automatic transmission unit for an electric vehicle with two forward speeds. In this unit, by switching the engagement states of two friction clutches, a first speed and a second speed with a gear ratio (= input rotational speed / output rotational speed) smaller than the first speed can be realized.

[0003] Similar units are also disclosed in Patent Documents 2 to 4.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] In an automatic transmission unit for an electric vehicle with two forward speeds, the greater the first speed gear ratio, the higher the torque amplification effect due to deceleration. Therefore, the greater the first speed gear ratio, the smaller the maximum torque of the motor can be, and a motor with a smaller size can be selected. On the other hand, the smaller the second speed gear ratio, the lower the rotational speed of the motor when achieving a certain vehicle speed, which is advantageous during high-speed cruising.

[0006] However, when setting the gear ratios of the first speed and the second speed respectively based on the above design concept, the step ratio (= gear ratio of the first speed / gear ratio of the second speed) when switching between the first speed and the second speed becomes large, and the acceleration and deceleration speed of the output rotation during gear shifting becomes large.

[0007] The present invention has been made in view of such technical problems, and an object thereof is to reduce the step ratio during gear shifting in a unit having a power transmission mechanism inside.

Means for Solving the Problems

[0008] According to an aspect of the present invention, the unit includes an input element, an output element, a first engaging element, a second engaging element, a third engaging element, a first planetary gear mechanism in which a first rotating element, a second rotating element, and a third rotating element are arranged in this order on a collinear diagram, and a second planetary gear mechanism in which a fourth rotating element, a fifth rotating element, and a sixth rotating element are arranged in this order on the collinear diagram. The input element is connected to the first rotating element and the sixth rotating element, The output element is connected to the second rotating element, One side of the first engaging element is connected to the third rotating element and the fifth rotating element, The other side of the first engaging element is fixed, One side of the second engaging element is connected to the fourth rotating element, The other side of the second engaging element is fixed, The third engaging element connects two non-connected rotating elements selected from the first to sixth rotating elements.

Effect of the Invention

[0009] According to the above aspect, by changing the engagement states of the first to third engagement elements, three or more shift speeds can be realized. As a result, the ratio between shift speeds becomes smaller compared to a two-forward-speed unit, and the acceleration and deceleration rates of the output rotation during shifting can be suppressed to be smaller than those of a two-forward-speed unit. Also, more appropriate gear ratios can be set for each shift speed.

[0010] Further, when the first and second engagement elements are disengaged and the third engagement element is engaged, the gear ratio becomes 1, and all the rotating elements constituting the first and second planetary gear mechanisms rotate at the same rotational speed. Therefore, the power transmission loss caused by the differential rotation between the rotating elements can be reduced.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The definitions of the terms used in this specification are as follows.

[0013] The "unit" generally means a device having a power transmission mechanism such as a gear mechanism or a differential gear mechanism inside, and includes a motor unit having a motor and a power transmission mechanism, an automatic transmission unit, a reduction gear unit, and the like.

[0014] The "transmission ratio" is the value obtained by dividing the input rotational speed of the unit by the output rotational speed. "Input rotation" includes not only the rotation input to the unit from a power source outside the unit but also the rotation input to the unit from a power source within the unit.

[0015] The "ratio between steps" is the value obtained by dividing the larger (for low speed) transmission ratio by the smaller (for high speed) transmission ratio for two transmission ratios achieved by the unit.

[0016] The "axial direction" means the axial direction of the rotation axis of the components constituting the unit. The components are a motor, a gear mechanism, a differential gear mechanism, etc. The "radial direction" means the radial direction from the central axis of the rotation axis.

[0017] The "housing" means a container that houses a motor, an inverter, and a power transmission mechanism, and is composed of one or more cases. A mode in which the case for housing the motor, the case for housing the inverter, and the case for housing the power transmission mechanism are integrally formed is called "3in1".

[0018] The "motor" means a rotating electrical machine having a motor function, and may also have a generator function in addition to the motor function.

[0019] "Element A is connected to element B" means that element A is connected to element B, which is upstream or downstream, in a manner that power can be transmitted between element A and element B. The power input side is upstream, and the power output side is downstream. It is not limited to a mode in which element A is directly or indirectly connected to element B via another member, and it may be connected via a clutch or the like.

[0020] "Element A is fixed to element B" includes both a mode in which element A is directly fixed to element B and a mode in which element A is fixed to element B via an element C other than element A and B. "Element A is fixed" means that element A is fixed to another element and is in a non-rotatable state.

[0021] "Element A and element B overlap in a specified viewing direction" means that element A and element B are arranged in a specified direction (axial direction, radial direction, gravitational direction, etc.), and when observed from the specified direction, element A and element B are in a state of at least partially overlapping. It is synonymous with "element A and element B overlap in the specified direction". When element A and element B overlap in the axial view, element A and element B are coaxial. When element A and element B are drawn side by side in a specified direction in the drawing, it means that element A and element B overlap in the specified viewing direction.

[0022] On the contrary, "element A and element B do not overlap in the specified viewing direction" means that element A and element B are not arranged in a specified direction (axial direction, radial direction, gravitational direction, vehicle traveling direction, etc.), and when observed from the specified direction, element A and element B do not have a overlapping part. It is synonymous with "element A and element B do not overlap in the specified direction". When element A and element B are drawn so as not to be arranged side by side in a specified direction in the drawing, it means that element A and element B do not overlap in the specified viewing direction.

[0023] "Element A is located between element B and element C in the specified viewing direction" means that when observed from the specified direction (axial direction, radial direction, gravitational direction, etc.), it is observed that element A is between element B and element C. For example, when element B, element A, and element C are arranged in this order along the axial direction, since it is observed that element A is between element B and element C in the radial view, it can be said that element A is located between element B and element C. It is not necessary for element A to overlap with element B and C in the axial view. When element A is drawn between element B and element C in the drawing, it means that element A is located between element B and element C in the specified viewing direction.

[0024] "Arranged in proximity" means that two elements have a portion that overlaps when viewed axially or radially, and there is no other element sandwiched between the two elements. For example, "two engaging elements are arranged in proximity" means that no planetary gear mechanism or the like is arranged between the two engaging elements. When no other element is depicted between element A and element B in the drawing, it means that element A and element B are arranged in proximity.

[0025] "One side of the engaging element" and "the other side of the engaging element" mean two elements included in the engaging element that become non-rotatable relative to each other when the engaging element is in the engaged state and become rotatable relative to each other when in the released state. "One side of the engaging element" and "the other side of the engaging element" may be a combination of rotating elements or a combination of a rotating element and a non-rotating element. Generally, the former is called a clutch and the latter is called a brake. Also, "one side of the engaging element" means either one of "one side of the engaging element" and "the other side of the engaging element".

[0026] Other terms will be appropriately defined in the main text of the specification.

[0027] Figure 1 is a skeleton diagram showing the basic structure of unit 100 according to an embodiment of the present invention. Unit 100 is an automatic transmission unit for an electric vehicle that shifts the rotation input to input element IN from a motor as a power source (not shown) at a gear ratio corresponding to the gear stage and transmits it from output element OUT to a drive wheel (not shown). In this example, both input element IN and output element OUT are rotating shafts.

[0028] Unit 100 is a so-called 3-in-1 unit that houses input element IN, first and second planetary gear mechanisms PG1, PG2, first to third engaging elements B1, B2, CL, output element OUT, a motor (not shown), and an inverter in housing 1. Housing 1 is fixedly non-rotatable with respect to the vehicle.

[0029] One end of the input element IN is connected to the output shaft of the motor, and the input element IN rotates by the power input from the motor. The rotational speed of the input element IN is the input rotational speed of the unit 100. The motor is electrically connected to a battery (not shown) outside the unit 100 via an inverter, receives power supply from the battery, and functions as an electric motor. Also, the motor can function as a generator.

[0030] The first planetary gear mechanism PG1 is a single pinion planetary gear mechanism having a first sun gear S1 as a first rotating element, a plurality of first pinion gears (not shown), a first carrier C1 as a second rotating element that rotatably supports the plurality of first pinion gears, and a first ring gear R1 as a third rotating element. The first sun gear S1 meshes with the plurality of first pinion gears, and the plurality of first pinion gears mesh with the first ring gear R1.

[0031] The second planetary gear mechanism PG2 is a single pinion planetary gear mechanism having a second sun gear S2 as a fourth rotating element, a plurality of second pinion gears (not shown), a second carrier C2 as a fifth rotating element that rotatably supports the plurality of second pinion gears, and a second ring gear R2 as a sixth rotating element. The second sun gear S2 meshes with the plurality of second pinion gears, and the plurality of second pinion gears mesh with the second ring gear R2.

[0032] The first sun gear S1 is connected to the input element IN and the second ring gear R2. The first carrier C1 is connected to the output element OUT. The first ring gear R1 is connected to the second carrier C2.

[0033] The rotational speed of the output element OUT is the output rotational speed of the unit 100.

[0034] The first engaging element B1 is a brake. The first engaging element B1 is constituted by a hydraulic or electric clutch. When the two parts of the first engaging element B1 that will be engaged when the first engaging element B1 is in the engaged state are regarded as one side and the other side, one side is connected to the first ring gear R1 and the second carrier C2, and the other side is fixed to the housing 1. Thereby, if the first engaging element B1 is engaged, the first ring gear R1 and the second carrier C2 can be fixed to the housing 1.

[0035] The second engaging element B2 is a brake. The second engaging element B2 is constituted by a hydraulic or electric clutch. When the two parts of the second engaging element B2 that will be engaged when the second engaging element B2 is in the engaged state are regarded as one side and the other side, one side is connected to the second sun gear S2, and the other side is fixed to the housing 1. Thereby, if the second engaging element B2 is engaged, the second sun gear S2 can be fixed to the housing 1.

[0036] The third engaging element CL is a clutch. The third engaging element CL is constituted by an electric multi-plate clutch.

[0037] The third engaging element CL includes a hub 11, inner friction plates 12 and outer friction plates 13 arranged alternately, a drum 14, and an electric actuator 15.

[0038] An inner friction plate 12 is spline-fitted to the outer periphery of the hub 11, and the inner friction plate 12 is axially relatively displaceable and non-rotatable relative to the hub 11. Also, the hub 11 is spline-fitted to the input element IN and is non-rotatable relative to the input element IN.

[0039] An outer friction plate 13 is spline-fitted to the inner periphery of the drum 14, and the outer friction plate 13 is axially relatively displaceable and non-rotatable relative to the drum 14. Also, the drum 14 is connected to the first carrier C1 and the output element OUT.

[0040] The electric actuator 15 is an actuator that drives the third engaging element CL. When the motor built into the electric actuator 15 is driven, the piston 15p is extended in the axial direction, and the inner friction plate 12 and the outer friction plate 13 are pressed against each other to become non-rotatable relative to each other, and the third engaging element CL is brought into an engaged state. Since the electric actuator 15 mechanically applies a force to the piston 15p and receives the reaction force from the piston 15p, the electric actuator 15 is fixed to the housing 1.

[0041] Also, when the motor built into the electric actuator 15 is driven in the reverse direction, the piston 15p retracts, the inner friction plate 12 and the outer friction plate 13 are separated, and the third engaging element CL is brought into a released state.

[0042] Note that instead of the electric actuator 15, it is also possible to use a hydraulic actuator that pushes out the piston 15p hydraulically. The supply of oil to the hydraulic actuator may be performed by a hydraulic supply unit attached to the housing 1 or the like, or may be performed by a control valve unit including a spool, a solenoid valve, or the like.

[0043] When the two parts of the third engaging element CL that are to be engaged when the third engaging element CL is in the engaged state are defined as one side (hub 11) and the other side (drum 14) respectively, one side is connected to the input element IN, the first sun gear S1, and the second ring gear R2, and the other side is connected to the first carrier C1 and the output element OUT. Thereby, when the third engaging element CL is engaged, the input element IN, the first sun gear S1, and the second ring gear R2 are connected to the first carrier C1 and the output element OUT.

[0044] Also, by connecting the first sun gear S1 and the first carrier C1 with the third engaging element CL, it is not necessary to arrange the third engaging element CL between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2, which facilitates the layout design.

[0045] As the actuator that can be used for the third engagement element CL, there are an actuator that is liable to be subject to layout constraints (such as an electric actuator that needs to be fixed to the housing 1 or the like in relation to the reaction force, a hydraulic actuator that needs to have a hydraulic supply unit attached to the housing 1 or the like) and an actuator that is less liable to be subject to layout constraints (such as a hydraulic actuator that is supplied with hydraulic pressure from a control valve unit). When using the former actuator, if it is necessary to arrange the third engagement element CL between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2, the difficulty of layout design increases.

[0046] Regarding this point, in the arrangement shown in FIG. 1, the layout design is easy regardless of the type of actuator, and the degree of freedom in selecting the actuator that drives the third engagement element CL can be increased.

[0047] Also, by arranging the second planetary gear mechanism PG2 on one axial side of the first planetary gear mechanism PG1 and arranging the third engagement element CL on the other axial side of the first planetary gear mechanism PG1, the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are arranged close to each other. As a result, the degree of freedom in layout of other elements increases, and the axial dimension of the unit 100 can be reduced.

[0048] Also, the third engagement element CL is arranged coaxially with the first and second planetary gear mechanisms PG1, PG2, and in the axial view, it has a portion that overlaps with the first planetary gear mechanism PG1 and a portion that overlaps with the second planetary gear mechanism PG2. Thereby, the radial dimension of the unit 100 can be reduced.

[0049] FIG. 2 is an engagement table showing the relationship between the engagement states of the first to third engagement elements B1, B2, CL and the gear shift stages realized in the unit 100. In the table, the black circles indicate the engaged states, and the blank indicates the released state.

[0050] As shown in the engagement table, the first gear is realized by engaging the first engagement element B1 and releasing the second and third engagement elements B2 and CL. The second gear is realized by engaging the second engagement element B2 and releasing the first and third engagement elements B1 and CL. The third gear is realized by engaging the third engagement element CL and releasing the first and second engagement elements B1 and B2.

[0051] Further, FIG. 3 is a collinearity diagram of the unit 100. In the figure, the vertical lines l1 to l4 correspond to the respective rotating elements of the first and second planetary gear mechanisms PG1 and PG2. Regarding the first planetary gear mechanism PG1, the first sun gear S1, the first carrier C1, and the first ring gear R1 are arranged in this order from the left side in the figure. Regarding the second planetary gear mechanism PG2, the second sun gear S2, the second carrier C2, and the second ring gear R2 are arranged in this order from the right side in the figure.

[0052] Since the first sun gear S1 and the second ring gear R2 are connected to each other, the same vertical line l1 corresponds to them. Similarly, since the first ring gear R1 and the second carrier C2 are also connected to each other, the same vertical line l3 corresponds to them. When the distance between the vertical lines l1 and l2 is set to 1, the distance α1 between the vertical lines l2 and l3 is the value obtained by dividing the number of teeth of the first sun gear S1 by the number of teeth of the first ring gear R1. Also, when the distance between the vertical lines l4 and l3 is set to 1, the distance α2 between the vertical lines l3 and l1 is the value obtained by dividing the number of teeth of the second sun gear S2 by the number of teeth of the second ring gear R2.

[0053] Straight lines L1 to L3 corresponding to each gear stage are drawn in the collinearity diagram. The rotational speed of each rotating element is represented by the ordinate of the intersection points of the straight lines L1 to L3 corresponding to each gear stage and the vertical lines l1 to l4.

[0054] In the first gear, by engaging the first engagement element B1, the first ring gear R1 and the second carrier C2 are fixed to the housing 1, and since the rotational speeds of the first ring gear R1 and the second carrier C2 become zero, the straight line L1 corresponding to the first gear is a straight line passing through the point X1.

[0055] When the rotational speeds of the first sun gear S1 and the second ring gear R2 are r4 and the rotational speed of the first carrier C1 is r1, the input rotational speed rin of the unit 100 is equal to the rotational speed r4 of the first sun gear S1 and the second ring gear R2, and the output rotational speed rout is equal to the rotational speed r1 of the first carrier C1. Therefore, the gear ratio in the first gear is rin / rout = r4 / r1.

[0056] Also, in the second gear, by engaging the second engaging element B2, the second sun gear S2 is fixed to the housing 1 and the rotational speed of the second sun gear S2 becomes zero. Therefore, the straight line L2 corresponding to the second gear is a straight line passing through the point X2.

[0057] When the rotational speeds of the first sun gear S1 and the second ring gear R2 are r4 and the rotational speed of the first carrier C1 is r2, the input rotational speed rin of the unit 100 is equal to the rotational speed r4 of the first sun gear S1 and the second ring gear R2, and the output rotational speed rout is equal to the rotational speed r2 of the first carrier C1. Therefore, the gear ratio in the second gear is rin / rout = r4 / r2. Since r2 is greater than r1, the gear ratio in the second gear is smaller than that in the first gear.

[0058] Also, in the third gear, by engaging the third engaging element CL, the input element IN, the first sun gear S1, and the second ring gear R2 are connected to the first carrier C1 and the output element OUT. Therefore, the rotational speeds of all the rotational elements become equal to r3. As a result, the input rotational speed rin and the output rotational speed rout also become equal, and the gear ratio in the third gear becomes 1, which is smaller than that in the second gear.

[0059] Therefore, in the unit 100, three gear stages including the third gear with a gear ratio of 1 can be realized. Compared with a two-forward-speed unit, the ratio between gear stages becomes smaller, and the acceleration and deceleration speed of the output rotation during gear shifting can be suppressed to be smaller than that of the two-forward-speed unit. Also, since the first to third gears can be used for low speed, medium speed, and high speed respectively, an appropriate gear ratio can be set according to the speed range.

[0060] Also, at the third speed, the gear ratio becomes 1. That is, since all the rotating elements constituting the first and second planetary gear mechanisms PG1 and PG2 rotate at the same rotational speed, the power transmission loss due to the differential rotation between the rotating elements can be reduced. In addition, the input element IN and the output element OUT are connected, and the power transmission path from the input element IN to the output element OUT becomes the shortest, further reducing the power transmission loss.

[0061] Next, a modified example of the unit 100 will be described.

[0062] Figs. 4A to 4C are skeleton diagrams of a modified example of the unit 100. The position of the third engaging element CL is different from the skeleton diagram shown in Fig. 1. The same elements as those in the skeleton diagram shown in Fig. 1 are labeled with the same reference numerals.

[0063] Since the third engaging element CL only needs to be engaged to achieve a gear ratio of 1, the position of the third engaging element CL may be other than the position shown in Fig. 1.

[0064] Specifically, in the collinearity diagram shown in Fig. 3, to achieve a gear ratio of 1, it is only necessary for the straight line L3 corresponding to the third speed to be horizontal. Therefore, any two of the four vertical lines can be selected, and the rotating elements corresponding to the selected two lines can be connected to each other.

[0065] In other words, from all the combinations of selecting two rotating elements from the six rotating elements S1, C1, R1, S2, C2, and R2 of the first and second planetary gear mechanisms PG1 and PG2, excluding the already connected combinations (the first sun gear S1 and the second ring gear R2, the first ring gear R1 and the second carrier C2), a combination of two non-connected rotating elements is selected, and these two rotating elements are connected.

[0066] In the modification shown in FIG. 4A, the third engagement element CL is arranged at a position where the input element IN, the first sun gear S1, and the second ring gear R2 can be connected to the second sun gear S2. Specifically, one side (hub 11) of the third engagement element CL is connected to the input element IN, the first sun gear S1, and the second ring gear R2, and the other side (drum 14) is connected to one side of the second engagement element B2 and the second sun gear S2.

[0067] This arrangement is suitable for a layout design in which the third engagement element CL is not arranged between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2. And if the third engagement element CL is not arranged between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2, the degree of freedom in selecting an actuator for driving the third engagement element CL can be increased.

[0068] As the actuator for driving the third engagement element CL, the same electric actuator 15 as shown in FIG. 1 may be used, or a hydraulic actuator supplied with hydraulic pressure from a hydraulic supply unit or a control valve unit attached to the housing 1 or the like may be used.

[0069] Also, the first planetary gear mechanism PG1 is arranged on one axial side of the second planetary gear mechanism PG2, and the third engagement element CL is arranged on the other axial side of the second planetary gear mechanism PG2.

[0070] Since the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are arranged close to each other, the degree of freedom in the layout of other elements is increased, and the axial dimension of the unit 100 can be reduced.

[0071] Also, since one side (drum 14) of the third engagement element CL is connected to one side of the second engagement element B2, these can be made into a common part (integrated part). Thereby, the number of parts of the unit 100 can be reduced.

[0072] Further, the third engagement element CL is arranged coaxially with the first and second planetary gear mechanisms PG1 and PG2, and in an axial view, it has a portion overlapping with the first planetary gear mechanism PG1 and a portion overlapping with the second planetary gear mechanism PG2. Thereby, the radial dimension of the unit 100 can be reduced.

[0073] In the modification shown in FIG. 4B, the third engagement element CL is arranged at a position where it can connect the input element IN, the first sun gear S1, and the second ring gear R2 to the first carrier C1 and the output element OUT. Specifically, one side (hub 11) of the third engagement element CL is connected to the input element IN, the first sun gear S1, and the second ring gear R2, and the other side (drum 14) is connected to the first carrier C1 and the output element OUT.

[0074] In this arrangement, since the third engagement element CL is arranged between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2, as the actuator for driving the third engagement element CL, it is preferable to use a hydraulic actuator 16 that supplies hydraulic pressure from a control valve unit with fewer layout constraints.

[0075] Further, the third engagement element CL is arranged coaxially with the first and second planetary gear mechanisms PG1 and PG2, and in an axial view, it has a portion overlapping with the first planetary gear mechanism PG1 and a portion overlapping with the second planetary gear mechanism PG2. Thereby, the radial dimension of the unit 100 can be reduced.

[0076] Further, when the third engagement element CL is engaged, in addition to being able to achieve a gear ratio of 1, since the input element IN and the output element OUT are connected, the power transmission path from the input element IN to the output element OUT becomes the shortest, and the power transmission loss can be further reduced.

[0077] In the modification shown in FIG. 4C, the third engaging element CL is arranged at a position where the input element IN, the first sun gear S1, and the second ring gear R2 can be connected to the first ring gear R1 and the second carrier C2. Specifically, one side (hub 11) of the third engaging element CL is connected to the input element IN, the first sun gear S1, and the second ring gear R2, and the other side (drum 14) is connected to one side of the first engaging element B1, the first ring gear R1, and the second carrier C2.

[0078] In this arrangement, since the third engaging element CL is arranged between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2, as the actuator for driving the third engaging element CL, it is preferable to use a hydraulic actuator 16 that supplies hydraulic pressure from a control valve unit with fewer layout constraints.

[0079] Further, the third engaging element CL is arranged coaxially with the first and second planetary gear mechanisms PG1, PG2, and in the axial view, it has a portion overlapping with the first planetary gear mechanism PG1 and a portion overlapping with the second planetary gear mechanism PG2. Thereby, the radial dimension of the unit 100 can be reduced.

[0080] Also, since one side (drum 14) of the third engaging element CL is connected to one side of the first engaging element B1, these can be made into a common part (integrated part). Thereby, the number of parts of the unit 100 can be reduced.

[0081] The engagement table and the collinearity diagram of the modifications shown in FIGS. 4A to 4C are the same as those of the skeleton diagram of FIG. 1 shown in FIGS. 2 and 3.

[0082] Next, the operation and effects of the embodiment of the present invention will be described.

[0083] (1) The unit 100 according to the embodiment of the present invention includes an input element IN, an output element OUT, a first engaging element B1, a second engaging element B2, The third engagement element CL, a first planetary gear mechanism PG1 in which a first sun gear S1, a first carrier C1, and a first ring gear R1 are arranged in this order on a collinear diagram, and a second planetary gear mechanism PG2 in which a second sun gear S2, a second carrier C2, and a second ring gear R2 are arranged in this order on a collinear diagram. The input element IN is connected to the first sun gear S1 and the second ring gear R2, the output element OUT is connected to the first carrier C1, one side of the first engagement element B1 is connected to the first ring gear R1 and the second carrier C2, the other side of the first engagement element B1 is fixed, one side of the second engagement element B2 is connected to the second sun gear S2, the other side of the second engagement element B2 is fixed, The third engagement element CL connects two non-connected rotating elements selected from the first sun gear S1, the first carrier C1, the first ring gear R1, the second sun gear S2, the second carrier C2, and the second ring gear R2.

[0084] According to this configuration, by changing the engagement states of the first to third engagement elements B1, B2, and CL, three or more speed ratios can be realized. As a result, the ratio between speed ratios becomes smaller compared to a two-speed forward unit, and the acceleration and deceleration rates of the output rotation during shifting can be suppressed to be smaller than those of the two-speed forward unit. Also, more appropriate speed ratios can be set for each speed ratio.

[0085] Further, when the first and second engagement elements B1 and B2 are disengaged and the third engagement element CL is engaged, the speed ratio becomes 1, and all the rotating elements constituting the first and second planetary gear mechanisms PG1 and PG2 rotate at the same rotational speed. Therefore, the power transmission loss due to the differential rotation between the rotating elements can be reduced.

[0086] (2) Also, in the example shown in FIG. 1, the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are single-pinion planetary gear mechanisms, and the third engagement element CL connects the first sun gear S1 and the first carrier C1.

[0087] This arrangement is suitable for a layout design in which the third engaging element CL is not arranged between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2. And if the third engaging element CL is not arranged between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2, the degree of freedom in selecting an actuator for driving the third engaging element CL can be increased.

[0088] In addition, when the third engaging element CL is engaged, in addition to being able to achieve a gear ratio of 1, since the input element IN and the output element OUT are connected, the power transmission path from the input element IN to the output element OUT becomes the shortest, and the power transmission loss can be further reduced.

[0089] (3) Also, in the example shown in FIG. 1, the second planetary gear mechanism PG2 is arranged on one axial side of the first planetary gear mechanism PG1, and the third engaging element CL is arranged on the other axial side of the first planetary gear mechanism PG1.

[0090] According to this configuration, the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are arranged close to each other. Thereby, the degree of freedom in the layout of other elements is increased, and the axial dimension of the unit 100 can be reduced.

[0091] (4) Also, in the example shown in FIG. 4A, the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are single-pinion planetary gear mechanisms, and the third engaging element CL connects the first sun gear S1 and the second sun gear S2.

[0092] This arrangement is suitable for a layout design in which the third engaging element CL is not arranged between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2. And if the third engaging element CL is not arranged between the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2, the degree of freedom in selecting an actuator for driving the third engaging element CL can be increased.

[0093] (5) Also, in the example shown in FIG. 4A, the first planetary gear mechanism PG1 is arranged on one axial side of the second planetary gear mechanism PG2, and the third engaging element CL is arranged on the other axial side of the second planetary gear mechanism PG2.

[0094] According to this configuration, since the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are arranged close to each other, the degree of freedom in the layout of other elements is increased, and the axial dimension of the unit 100 can be reduced.

[0095] (6) Also, in the examples shown in FIGS. 1, 4A to 4C, in the axial view, the third engaging element CL has a portion that overlaps with the first planetary gear mechanism PG1. Also, in the axial view, the third engaging element CL has a portion that overlaps with the second planetary gear mechanism PG2.

[0096] Thereby, the radial dimension of the unit 100 can be reduced.

[0097] (7) Also, in the examples shown in FIGS. 4A and 4C, one side (drum 14) of the third engaging element CL is connected to one side of the first engaging element B1 or one side of the second engaging element B2.

[0098] According to this configuration, one side of the third engaging element CL and one side of the first engaging element B1 or one side of the second engaging element B2 can be made into a common part (integral part), and thereby, the number of parts of the unit 100 can be reduced.

[0099] As described above, the embodiments of the present invention have been described. However, the above embodiments are merely application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0100] For example, the skeleton diagrams shown in FIGS. 1, 4A to 4C are part of the application examples of the present invention, and the skeleton diagrams of the unit to which the present invention is applied are not limited to these.

[0101] In addition, the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2 are each a single-pinion planetary gear mechanism, but they may also be double-pinion planetary gear mechanisms.

Explanation of Signs

[0102] 1: Housing 100: Unit B1: First engaging element B2: Second engaging element CL: Third engaging element S1: First sun gear (first rotating element) C1: First carrier (second rotating element) R1: First ring gear (third rotating element) S2: Second sun gear (fourth rotating element) C2: Second carrier (fifth rotating element) R2: Second ring gear (sixth rotating element) IN: Input element OUT: Output element PG1: First planetary gear mechanism PG2: Second planetary gear mechanism

Claims

1. An input element, an output element, a first engaging element, a second engaging element, a third engaging element, a first planetary gear mechanism in which a first rotating element, a second rotating element, and a third rotating element are arranged in this order on a collinear diagram, a second planetary gear mechanism in which a fourth rotating element, a fifth rotating element, and a sixth rotating element are arranged in this order on the collinear diagram, and the input element is connected to the first rotating element and the sixth rotating element, the output element is connected to the second rotating element, one side of the first engaging element is connected to the third rotating element and the fifth rotating element, the other side of the first engaging element is fixed, one side of the second engaging element is connected to the fourth rotating element, the other side of the second engaging element is fixed, and the third engaging element is a unit that connects two rotating elements selected from the first to sixth rotating elements and not connected to each other.

2. In the unit according to Claim 1, the first planetary gear mechanism and the second planetary gear mechanism are single-pinion planetary gear mechanisms, and the third engaging element is a unit that connects the first rotating element and the second rotating element.

3. In the unit according to Claim 2, the second planetary gear mechanism is arranged on one axial side of the first planetary gear mechanism, and the third engaging element is arranged on the other axial side of the first planetary gear mechanism.

4. In the unit according to Claim 1, the first planetary gear mechanism and the second planetary gear mechanism are single-pinion planetary gear mechanisms, and the third engaging element is a unit that connects the first rotating element and the fourth rotating element.

5. In the unit according to Claim 4, the first planetary gear mechanism is arranged on one axial side of the second planetary gear mechanism, and the third engaging element is arranged on the other axial side of the second planetary gear mechanism.

6. In the unit according to Claim 3 or Claim 5, in an axial view, the third engaging element has a portion overlapping with the first planetary gear mechanism, and in an axial view, the third engaging element has a portion overlapping with the second planetary gear mechanism.

7. In the unit according to Claim 1, one side of the third engaging element is connected to one side of the first engaging element or one side of the second engaging element.

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