JP6090139B2 - In-wheel motor unit - Google Patents

Description

  The present invention relates to an in-wheel motor unit provided in a wheel.

  Conventionally, a structure of an in-wheel motor that rotates a wheel by a motor disposed in the wheel is known (see, for example, Patent Document 1). This conventional in-wheel motor structure includes a piston pump having a piston and a cylinder. In this piston type pump, the piston reciprocates in conjunction with the rotation of the eccentric cam assembled to the shaft of the counter gear (rotating body) to which the rotation of the motor is transmitted. As a result, in the structure of the conventional in-wheel motor, when the eccentric cam rotates with the rotation of the counter gear, the piston-type pump operates to pump up the oil in the oil tank. Used for lubrication.

JP 2008-87713 A

  By the way, in the structure of the conventional in-wheel motor, the shaft of the counter gear has a protruding portion that extends through the counter gear. The eccentric cam is provided on the protruding portion of the counter gear and abuts against the back surface of the piston having a predetermined diameter to press the piston. However, since the cam diameter of the eccentric cam is generally smaller than the radius of the counter gear, the eccentric cam cannot press down the piston when the piston type pump is arranged radially outward (for example, directly below) of the counter gear. Therefore, in order to prevent the piston-type pump from being pushed down directly by the eccentric cam and from interfering with the counter gear, the pump is moved from the counter gear to the axial direction of the shaft, not radially outward (for example, directly below). Along with this, it must be disposed at a position separated by an appropriate distance, and accordingly, the length of the protruding portion of the shaft must be increased. Furthermore, in order to avoid interference with the eccentric cam provided in the protruding portion, it is necessary to dispose the motor at a suitable distance from the eccentric cam along the axial direction of the shaft. As a result, the conventional in-wheel motor unit has a problem that the axial dimension of the shaft becomes large.

  On the other hand, it is conceivable to suppress an increase in the dimension of the in-wheel motor unit in the axial direction by disposing the piston-type pump radially outward of the counter gear. However, in this case, the cam diameter of the eccentric cam must be larger than the radius of the counter gear, so that it does not interfere with other members (for example, a motor output shaft) when the eccentric cam rotates. Space must be secured. As a result, there exists a problem that the dimension of the direction orthogonal to the axial direction of the shaft of an in-wheel motor unit becomes large.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an in-wheel motor unit that can be downsized even if it has a mechanism for driving a pump for lubrication. .

  In the in-wheel motor unit of the present invention for achieving the above object, the pin is provided at a position separated from the rotation center axis of the rotating body of the speed reduction mechanism. For this reason, when the rotating body of the speed reduction mechanism is rotated by the motor, the pin can rotate around the rotation center axis of the rotating body. Further, in the in-wheel motor unit of the present invention, the rod is rotatably connected to the pin at one end and is swingably connected to the piston at the other end. For this reason, when the pin rotates together with the rotating body, the rod can reciprocate the piston in the cylinder in accordance with the rotation of the pin. That is, in the in-wheel motor unit of the present invention, a crank mechanism that reciprocates the piston of the pump is constituted by the rotating body, the pin, and the rod.

Moreover, in the in-wheel motor unit of this invention, a pin and a rod are arrange | positioned in the clearance gap which exists between a motor and a rotary body, and the rod has connected the pin and the piston using the said clearance gap. Thereby, the pump can be driven. As a result, downsizing of the in-wheel motor unit can be achieved. In this case, for example, even when a pump having a large piston diameter is disposed on the outer side in the radial direction of the rotating body (for example, counter gear), the crank mechanism does not increase the size of the in-wheel motor unit. Can be reciprocated. Furthermore, the pump can be provided by efficiently utilizing the limited space in the in-wheel motor unit.

  Furthermore, in the in-wheel motor unit of the present invention, since the piston can be reciprocated by the crank mechanism, it is not necessary to provide a separate spring for pushing back the piston. Therefore, for example, the pump can be operated without being affected by the resonance frequency or the like of the spring, so that the lubricating oil can be appropriately supplied to the lubricating path in the in-wheel motor unit. As a result, good lubrication in the in-wheel motor unit can be maintained.

It is a schematic side view of the in-wheel motor unit which shows the principal part of the in-wheel motor unit which concerns on embodiment of this invention, and shows the lubricating oil discharge operation | movement of a pump. It is a schematic side view of the in-wheel motor unit which shows the lubricating oil suction | inhalation operation | movement of the pump of FIG. It is the schematic which shows operation | movement of the crank mechanism comprised by the counter gear of FIG. 1, a pin, and a rod.

  Hereinafter, an in-wheel motor unit (hereinafter also simply referred to as “unit”) according to an embodiment of the present invention will be described with reference to the drawings. This unit is supported by the suspension of the vehicle and provided in the wheel. The unit includes a motor, and drives the wheel by transmitting output from the motor to the wheel.

  As shown in FIGS. 1 and 2, the unit (IWM unit) 10 includes a housing 11, a motor 12, a speed reduction mechanism 13, a lubrication mechanism 14, a pin 15, and a rod 16. The housing 11 is configured to be liquid-tight and accommodates a motor 12, a speed reduction mechanism 13, a lubrication mechanism 14, a pin 15, and a rod 16.

  The motor 12 is fixed to the housing 11. The motor 12 includes a motor output shaft 12a. The motor output shaft 12a is rotatably supported by a bearing BR1 and a bearing BR2. The motor output shaft 12a extends in the vehicle axle direction. A small-diameter gear 13a that forms the speed reduction mechanism 13 is fixed to the distal end side of the motor output shaft 12a.

  The speed reduction mechanism 13 includes a large-diameter counter gear 13b as a rotating body that meshes with the small-diameter gear 13a. The speed reduction mechanism 13 includes a drive output shaft 13c extending in the axle direction. The base end side of the drive output shaft 13c is fixed to the counter gear 13b. The drive output shaft 13c is rotatably supported by a bearing BR3 and a bearing BR4. The front end side of the drive output shaft 13 c is fixed to the wheel W via the hub H.

  The lubrication mechanism 14 includes a pump 14a, a reservoir 14b, and a lubricating oil supply path 14c. The pump 14a is a so-called reciprocating pump including a cylinder 14a1, a piston 14a2, and a check valve 14a3. The cylinder 14a1 is fixed to the housing 11. The cylinder 14a1 communicates with the reservoir 14b so as to suck the lubricating oil stored in the reservoir 14b at one end thereof. The piston 14a2 reciprocates in the cylinder 14a1. The check valve 14a3 is provided in the vicinity of the opening end on one end side of the cylinder 14a1. The check valve 14a3 allows only the flow of lubricating oil from the reservoir 14b into the cylinder 14a1. The lubricating oil supply path 14c supplies the lubricating oil pumped up from the oil reservoir 14b by the pump 14a to the bearings BR1 to BR4 and the motor 12. For this reason, the lubricating oil supply path 14c includes a plurality of discharge ports 14c1. Further, a check valve 14c2 is provided in the lubricating oil supply passage 14c. The check valve 14c2 allows only the flow of lubricating oil from the cylinder 14a1 of the pump 14a toward the discharge port 14c1.

  As shown in FIG. 3, the pin 15 and the rod 16 convert the counter gear 13 b together with the counter gear 13 b into the linear motion (reciprocating motion) of the piston 14 a 2 as shown in FIG. 3. A crank mechanism is configured. More specifically, the pin 15 is provided at a position spaced apart from the center of the counter gear 13b by a predetermined distance in the radial direction. One end of the rod 16 is connected to the pin 15 so as to be rotatable about the axis of the pin 15, and the other end is connected to the piston 14a2 so as to be swingable in a plane orthogonal to the axis of the counter gear 13b. The position where the pin 15 is provided on the counter gear 13b is such that the reciprocating piston 14a2 is not detached from the cylinder 14a1, and the rod 16 connected so as to be swingable is not in contact with the inner peripheral surface of the cylinder 14a1. It is determined. Further, the pin 15 and the rod 16 are disposed in a gap existing between the motor 12 and the counter gear 13 b in the housing 11.

  When the counter gear 13b is rotated by the motor 12, the pin 15 rotates around the rotation center axis of the counter gear 13b. The rod 16 is rotatably connected to the pin 15 at one end and is swingably connected to the piston 14a2 at the other end. Therefore, when the pin 15 rotates together with the counter gear 13b, the rod 16 reciprocates the piston 14a2 in the cylinder 14a1 according to the rotation of the pin 15 (see FIG. 3). Therefore, the crank mechanism constituted by the counter gear 13b, the pin 15 and the rod 16 can drive the pump 14a.

  The pump 14a driven by the crank mechanism pumps the lubricating oil from the reservoir 14b and lubricates the pumped lubricating oil by the reciprocating motion of the piston 14a2, regardless of whether the counter gear 13b is rotating forward or backward (forward or reverse rotation of the motor 12). The oil is discharged into the oil supply path 14c (see FIGS. 1 and 2). The lubricating oil supply path 14c supplies lubricating oil to the bearings BR1 to BR4 through the discharge ports 14c1. As a result, good lubrication of the bearings BR1 to BR4 can be maintained. The lubricating oil discharged from the pump 14 a is also supplied to a heat generating part such as a rotor constituting the motor 12. Thereby, it is possible to satisfactorily cool the motor 12 that generates heat as the driving force is generated.

  As can be understood from the above description, in the in-wheel motor unit 10 of the above embodiment, the counter gear 13b of the speed reduction mechanism 13, the pin 15 and the rod 16 constitute a crank mechanism for reciprocating the piston 14a2 of the pump 14a. . Thereby, the rod 16 can drive the pump 14a by connecting the pin 15 and the piston 14a2 by using a gap or the like existing between the motor 12 and the speed reduction mechanism 13, for example. For this reason, it is not necessary to arrange | position the pump 14a between the motor 12 and the speed reduction mechanism 13, As a result, size reduction of the in-wheel motor unit 10 can be achieved.

  In carrying out the present invention, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the object of the present invention.

  For example, in the above-described embodiment, the case where the speed reduction mechanism 13 includes the small-diameter gear 13a and the counter gear 13b has been described. However, for example, a speed reduction mechanism using a plurality of pressure rollers can be employed. It is. Even in this case, an effect equivalent to that of the above-described embodiment can be obtained by providing the pin 15 integrally with any one of the pressure rollers as a rotating body and connecting the rod 16 to the pin 15 so as to be rotatable. It is done.

  Further, in the above embodiment, the speed reduction mechanism 13 is implemented by adopting a one-stage speed reduction structure composed of the small diameter gear 13a and the counter gear 13b. In this case, it is needless to say that a multistage reduction structure can be employed.

DESCRIPTION OF SYMBOLS 10 ... In-wheel motor unit, 12 ... Motor, 13 ... Deceleration mechanism, 13b ... Counter gear (rotary body), 14 ... Lubrication mechanism, 14a ... Pump, 14a2 ... Piston, 15 ... Pin, 16 ... Rod

Claims (1)

A motor,
A speed reduction mechanism including a rotating body rotated by the motor and transmitting the rotation of the motor to the wheel through the rotating body;
A lubrication mechanism including a pump having a piston and a cylinder and supplying lubricating oil pumped up by the pump to the motor and the speed reduction mechanism;
An in-wheel motor unit provided in a wheel,
A pin provided on the rotating body at a position away from the rotation center axis of the rotating body of the speed reduction mechanism;
A rod having one end rotatably connected to the pin and the other end swingably connected to the piston;
With
A crank mechanism configured to reciprocate the piston by the rotating body, the pin and the rod ; and
The pin and the rod are disposed in a gap existing between the motor and the rotating body, and the rod connects the pin and the piston using the gap. Wheel motor unit.

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