JP2010083265A - Drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive unit which can be made in a simple structure even if a serial hybrid system is adopted to a large-sized truck. <P>SOLUTION: Drive motors 38 and 39 for driving by electric power charged in an electrical storage body 18 are arranged near a brake drum 36 in an outer circumferential surface of an axle case 34. The drive motors 38 and 39 are a pair of motors which are arranged on both sides holding the axle case 34, and are located inside of the brake drum 36. Driving forces of the drive motors 38 and 39 are transmitted to rear wheels 14 and 15 via pinion gears 38b and 39b and a ring gear 36b to rotate the rear wheels. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive unit including an axle case in which a drive shaft that rotates a wheel of a vehicle such as a large truck is housed.

  Equipped with a power generation engine (internal combustion engine) and a power storage unit (such as a secondary battery) that stores the power generated by the engine, and drives the motor with the power stored in the power storage unit to rotate the wheels. A serial hybrid vehicle that travels in accordance with is known. Some serial hybrid vehicles are provided with a dedicated drive motor for each wheel connected to both longitudinal ends of the drive shaft. These drive motors are disposed in the wheel and are called so-called wheel-in motors (see, for example, Patent Document 1).

In general, a relatively lightweight vehicle such as a passenger car or a small truck has a small driving force per wheel (per wheel), an outer diameter that is equal to or less than the wheel rim diameter, and a length that is about the width of the wheel. Even if a drive motor is used, the wheel can be sufficiently driven, so that a layout like the wheel-in motor described above is possible. On the other hand, the driving wheel of a large truck has a structure in which two tires and wheels are attached to one hub, and a larger driving force is required compared to the size of the wheel. For this reason, when a large truck is used as a serial hybrid vehicle, it is necessary to make the outer diameter of the drive motor that drives the wheels larger than the rim diameter of the wheels or make the length of the drive motor larger than the width of the wheels. Therefore, the layout like the wheel-in motor described above cannot be used for large trucks, and a larger drive motor is placed behind the engine, and the wheels are driven via a propeller shaft, differential gear, axle shaft, etc. The driving type is common. In such a type, the drive system has almost the same configuration as that of the engine vehicle.
JP-A-11-262101

  As described above, the structure employing the serial hybrid system for large trucks cannot use a wheel-in motor employed in a small vehicle such as a passenger car, and therefore cannot have a structure without a differential gear or an axle shaft. For this reason, the drive unit comprised from a drive shaft etc. cannot be made into a simple structure.

  In view of the above circumstances, an object of the present invention is to provide a drive unit that can have a simple structure even when a serial hybrid system is employed in a large truck.

In order to achieve the above object, the drive unit of the present invention comprises:
(1) an axle case containing a drive shaft for rotating a wheel;
(2) a brake drum that is rotatably fixed to both ends of the axle case in the longitudinal direction and rotates together with the wheel;
(3) a power storage unit for storing electric power;
(4) a drive motor that is disposed in the vicinity of the brake drum on the outer peripheral surface of the axle case and that is driven by electric power stored in the power storage unit;
(5) A power transmission member that transmits the driving force of the driving motor to the brake drum is provided.

here,
(6) The power transmission member is
(6-1) a pinion gear fixed to the rotating shaft of the drive motor;
(6-2) A ring gear fixed to the outer peripheral surface of the brake drum and meshing with the pinion gear may be used.

Also,
(7) The drive motor may be a pair of motors disposed on both sides of the axle case.

further,
(8) You may provide the gear cover which covers the said pinion gear and the said ring gear watertightly.

Furthermore,
(9) The gear cover may be fixed to the axle case via a bracket fixed to a brake mounting bracket for mounting a brake for braking the wheel.

Furthermore,
(10) The gear cover may be fixed to the axle case through a bracket formed integrally with a brake mounting bracket for mounting a brake for braking the wheel.
(11) The drive motor may be fixed to the axle case via a motor mounting bracket and the gear cover.

  According to the present invention, the drive motor is disposed in the vicinity of the brake drum on the outer peripheral surface of the axle case, and the driving force of the drive motor is transmitted to the brake drum by the power transmission member to rotate the wheel. Therefore, a propeller shaft and a differential gear are not required, and a drive unit having a structure as simple as that of a conventional wheel-in motor type can be adopted for a large truck.

  The present invention has been realized in a large truck having a structure in which two tires and wheels are attached to one hub.

  With reference to FIG. 1, a schematic structure of a large truck in which the drive unit of the present invention is adopted will be described.

  FIG. 1 is a bottom view showing a schematic structure of a large truck.

  The large truck 10 includes two front wheels (tires) 12 and rear wheels 14 and 15 mounted on a hub in two (14a and 14b and 15a and 15b). The rear wheel 14 and the rear wheel 15 are connected to a drive shaft 32 (see FIG. 2) housed in an axle case 34. Below the driver's seat 17, an engine (internal combustion engine) 16 dedicated to power generation is arranged. The engine 16 only drives the generator 19, and the electric power obtained here is stored (charged) in a power storage body (charged body) 18 such as a secondary battery, and a conductive cable (conductive wire). 20 is supplied to the drive motors 38 and 39. A generator 19 is disposed between the engine 16 and the power storage unit 18. The arrangement of the drive motors 38 and 39 will be described with reference to FIGS.

  FIG. 2 is a perspective view showing a drive unit including a drive motor from the inside (inside the vehicle), and a part thereof is broken away. FIG. 3 is a perspective view showing a drive unit including a drive motor from the outside (vehicle outside), and a part thereof is broken away. FIG. 4 is a partial cross-sectional view showing the vicinity of the drive motor in the drive unit.

  The drive unit 30 includes an axle case 34 that houses a drive shaft 32 to which the rear wheels 14 and 15 are fixed. A brake drum 36 that rotates together with the rear wheels 14 and 15 is rotatably fixed to both longitudinal ends of the axle case 34. In the vicinity of the brake drum 36 on the outer peripheral surface of the axle case 34, drive motors 38 and 39 that are driven by the electric power stored in the power storage unit 18 are disposed. The drive motors 38, 39 are a pair of motors disposed on both sides of the axle case 34, and are located on the inner side of the brake drum 36. The drive motors 38 and 39 are fixed to the axle case 34 via an L-shaped bracket 40 and a gear cover 42. When the brake is driven by air, one drive motor 38 (or 39) may be arranged on the opposite side of the brake drive air chamber. When the brake is hydraulically driven, the drive motors 38 and 39 are connected to the axle. A total of two cases 34 may be arranged in the vehicle longitudinal direction of the case 34.

  The rotation shafts 38a and 39a of the drive motors 38 and 39 extend outward from the vehicle in parallel with the axle case 34, and pinion gears 38b and 39b are fixed to the rotation shafts 38a and 39a, respectively. Further, a ring gear 36b that meshes with the pinion gears 38b and 39b is fixed to the outer peripheral surface of the brake drum 36. Accordingly, the driving force (rotational force) of the drive motors 38, 39 is transmitted to the brake drum 36 by the pinion gears 38b, 39b and the ring gear 36b, whereby the rear wheels 14, 15 are rotated. The driving force of the drive motors 38 and 39 may be transmitted to the brake drum 36 with an endless belt. Further, in order to transmit the driving force of the drive motors 38 and 39 to the brake drum 36 at a predetermined reduction ratio, the pinion gears 38b and 39b and the ring gear 36b may be of the same module, although the number of teeth is different.

  The above-described pinion gears 38b and 39b and the ring gear 36b are watertightly covered by a disk-shaped gear cover 42 in which a space is formed. By storing lubricating oil or the like in the gear cover 42, the pinion gears 38b and 39b and the ring gear 36b can be smoothly rotated to enhance durability. The gear cover 42 is attached to a brake attachment bracket 44 for attaching a brake (not shown) for braking the rear wheels 14 and 15. In addition, you may comprise a part of gear cover 42 with a sealing material. The seal material and the ring gear 36b may be integrated with the brake drum 36. However, in order to avoid the influence of frictional heat accompanying braking and to ensure the durability of the seal material and the ring gear 36b, The drum 36 may be made of a material different from gray cast iron, which is a general material, and may be connected to the brake drum 36 body with a structure having a high torque transmission capability such as a spline.

  Another example of the gear cover attaching method will be described with reference to FIGS.

  FIG. 5 is a perspective view showing a gear cover fixed to the axle case via a bracket, with a part broken away. FIG. 6 is a perspective view showing a gear cover fixed via a bracket integrally formed with the brake mounting bracket, and a part thereof is broken away. In these drawings, the same components as those shown in FIGS. 2 and 3 are denoted by the same reference numerals.

  As shown in FIG. 5, the gear cover 42 is fixed to the axle case 34 via a bracket 46 fixed to a brake mounting bracket 44 for mounting a brake for braking the rear wheels 14 and 15. Instead of the structure shown in FIG. 5, as shown in FIG. 6, a bracket 48 is integrally formed on a brake mounting bracket 44 for mounting a brake for braking the rear wheels 14, 15. Alternatively, the gear cover 42 may be fixed to the axle case 34.

  As described above, since the drive motors 38 and 39 are fixed to the axle case 34 and the rear wheels 14 and 15 are driven, there is no need for a propeller shaft or a differential gear, which is equivalent to the conventional wheel-in motor type. Therefore, a drive unit with a simple structure can be used for a large truck. Further, since the engine 16 is dedicated to power generation, it can be small and the power storage unit 18 can be small.

  In the present invention, the drive motor is driven by the electric power stored in the electric storage body. However, depending on the driving conditions of the vehicle, the electric power generated by the engine may be used alone or by using both of these electric powers simultaneously.

  Furthermore, although the present invention assumes a drive unit for double tires such as a large truck, the present invention may be applied to a drive unit for single tires such as a small truck.

It is a bottom view showing a schematic structure of a large truck. It is a perspective view which shows the drive unit provided with the drive motor from the inner side (vehicle inside), and is partially broken and shown. It is a perspective view which shows the drive unit provided with the drive motor from the outer side (vehicle outer side), and is partially broken and shown. It is a partial cross section figure which shows a drive motor vicinity among drive units. It is a perspective view which shows the gear cover fixed to the axle case via the bracket, and is partially cut away. It is a perspective view which shows the gear cover fixed via the bracket integrally formed with the bracket for brake attachment, and is partially broken and shown.

Explanation of symbols

10 Large trucks 14 and 15 Rear wheels 16 Engine 18 Power storage unit 30 Drive unit 34 Axle case 36 Brake drum 36b Ring gears 38 and 39 Drive motors 38b and 39b Pinion gear 40 Bracket 42 Gear cover

Claims (7)

An axle case containing a drive shaft for rotating the wheel;
A brake drum that is rotatably fixed to both longitudinal ends of the axle case, and rotates with the wheel;
A power storage unit for storing electric power;
A drive motor that is disposed near the brake drum on the outer peripheral surface of the axle case, and that is driven by electric power stored in the power storage unit;
A drive unit comprising: a power transmission member that transmits a drive force of the drive motor to the brake drum. The power transmission member is
A pinion gear fixed to the rotating shaft of the drive motor;
2. The drive unit according to claim 1, comprising a ring gear fixed to the outer peripheral surface of the brake drum and meshing with the pinion gear. The drive unit according to claim 1 or 2, wherein the drive motor is a pair of motors disposed on both sides of the axle case. The drive unit according to claim 2, further comprising a gear cover that covers the pinion gear and the ring gear in a watertight manner. The gear cover is
The drive unit according to claim 4, wherein the drive unit is fixed to the axle case via a bracket fixed to a brake mounting bracket for mounting a brake for braking the wheel. The gear cover is
5. The drive unit according to claim 4, wherein the drive unit is fixed to the axle case through a bracket integrally formed with a brake mounting bracket for mounting a brake for braking the wheel. The drive motor is
The drive unit according to claim 1, wherein the drive unit is fixed to the axle case via a motor mounting bracket and the gear cover.

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