Driving source assembly

1. A driving source assembly comprising:

a prime mover including a driving shaft;

a continuously variable transmission including a CVT structure and a CVT case and lined up with respect to the prime mover in a predetermined arrangement direction, the CVT structure changing rotational speed of rotational power input from the driving shaft, the CVT case defining a main accommodating space accommodating the CVT structure;

a first gear that is between the prime mover and the CVT case and rotates together with the driving shaft;

a second gear that is meshable with the first gear;

an energy converter including a rotating shaft that rotates in association with the second gear;

a plate which includes a first surface and a second surface and is fixed to the prime mover and to which the energy converter is fixed, the first surface being opposed to the prime mover and the energy converter, the second surface being opposed to the CVT case; and

a seal, wherein:

a side of the continuously variable transmission which is close to the prime mover in the arrangement direction is referred to as a first side;

a side of the continuously variable transmission which is far from the prime mover in the arrangement direction is referred to as a second side;

the first gear is between the plate and the CVT case;

the CVT case includes a recess that defines an auxiliary accommodating space accommodating the first gear and is open toward the first side in the arrangement direction;

the plate closes an opening of the recess from the first side in the arrangement direction; and

the seal surrounds the opening and is between the recess and the plate.

2. The driving source assembly according to claim 1 , wherein:

the seal is a first seal;

the plate further includes a first insertion hole in which the driving shaft is; and

the driving source assembly further includes a second seal that is between the prime mover and the plate at a position around the first insertion hole.

3. The driving source assembly according to claim 1 , wherein:

the plate further includes a second insertion hole in which the rotating shaft is;

the energy converter includes a housing including an end surface opposed to the plate; and

the end surface of the housing is in surface contact with the first surface of the plate at a position around the second insertion hole.

4. The driving source assembly according to claim 1 , wherein:

the prime mover includes an internal combustion engine;

the driving shaft includes a crank shaft; and

the first gear is a flywheel that is at the crank shaft and includes external teeth at an outer peripheral portion of the flywheel.

5. The driving source assembly according to claim 4 , wherein the energy converter includes a starter motor.

6. The driving source assembly according to claim 1 , wherein:

the CVT case includes:

a case main body including a main opening through which the main accommodating space is open toward the second side in the arrangement direction, and

a cover that is attached to the case main body and closes the main opening; and

the case main body includes:

a main case defining the main accommodating space,

an auxiliary case including the recess and an inflow opening which communicates with the main accommodating space and into which the cooling air flows, the auxiliary case being fixed to the main case, and

a cooling air passage which is between the main case and the auxiliary case and through which the inflow opening communicates with the main accommodating space.

7. The continuously variable transmission according to claim 6 , wherein:

the auxiliary case includes a contact surface that is in contact with the plate at a position around the opening of the recess;

the contact surface includes a seal groove surrounding the opening of the recess of the auxiliary case; and

the seal is at the seal groove.

8. The continuously variable transmission according to claim 6 , wherein:

the recess includes a first recess; and

the auxiliary case further includes a second recess that is adjacent to the first recess in a direction orthogonal to the arrangement direction, defines the cooling air passage between the main case and the second recess, and is open toward the second side in the arrangement direction.

9. The continuously variable transmission according to claim 8 , wherein

the auxiliary case is one piece,

the auxiliary case includes:

an auxiliary case main body portion including the recess; and

a tubular fitting portion projecting from the auxiliary case main body portion and including the inflow opening, and

the tubular fitting portion projects from a bottom wall of the second recess toward the first side in the arrangement direction.

10. The continuously variable transmission according to claim 8 , wherein:

the auxiliary case further includes a third recess that is open toward the second side in the arrangement direction, a bottom wall of the first recess being used as a bottom wall of the third recess, and;

the second recess and the third recess are continuous with each other;

entirety of the second recess and the third recess includes a recess that is open toward the second side in the arrangement direction;

the second recess defines an upstream space of the cooling air passage; and

the third recess defines a downstream space of the cooling air passage.

11. The continuously variable transmission according to claim 10 , wherein the second recess is adjacent to both the first recess and the third recess in the direction orthogonal to the arrangement direction.

12. The driving source assembly according to claim 6 , wherein:

the auxiliary case is one piece; and

the auxiliary case includes:

an auxiliary case main body portion including the recess; and

a tubular fitting portion projecting from the auxiliary case main body portion and including the inflow opening.