Patent Description:
A drive device for a vehicle that is disclosed in <CIT> has a configuration in which a motor case that houses a motor, a gear case that houses a gear unit, and an electric power conversion unit case that houses an electric power conversion unit are integrally fastened.

For an integrated drive device such as the above drive device for the vehicle that is disclosed in <CIT>, it is desired to achieve both the securement of the capacities of the gear case and the electric power conversion unit case and the reduction in the physical size of the drive device.

Hence, the present invention discloses an integrated drive device that allows the reduction in physical size.

An aspect of the present invention relates to a drive device for a vehicle that includes a motor case, a first case, and a second case. The motor case is configured to house a motor. The first case is configured to house a gear unit that is mechanically connected with the motor. The second case is configured to house an electric power conversion unit that is electrically connected with the motor. The first case and the second case are fastened to the motor case by a plurality of fastening members. The plurality of fastening members includes at least one common fastening member that concurrently fastens the first case and the second case to the motor case.

In the drive device, generally, in a configuration in which fastening members are used for fastening cases, a space for disposing fastening members is necessary. As a result, in some cases, the capacities of the cases cannot be secured, or the physical size of the drive device is increased. The drive device for the vehicle in the above aspect includes the common fastening member that concurrently fastens the first case and the second case to the motor case. Thereby, the total number of necessary fastening members can be reduced. Since the total number of fastening members can be reduced, the space for disposing fastening members can be reduced. It is possible to achieve the securement of the capacities of the first case and the second case and the reduction in the physical size of the drive device.

In the drive device for the vehicle in the aspect of the present invention, the second case may be disposed on the first case, at the position of the at least one common fastening member.

In the above configuration, it is possible to concurrently fasten the first case and the second case to the motor case.

In the drive device for the vehicle that has the above configuration, the first case may include a first flange that extends along an outer periphery of the first case and that is fixed to the motor case by some of the plurality of fastening members. The second case may include a second flange that extends along an outer periphery of the second case and that is fixed to the motor case by some of the plurality of fastening members. A part of the first flange may include an overlap section that is positioned between the motor case and the second flange. The at least one common fastening member may include at least one first common fastening member that is positioned at the overlap section.

In the above configuration, it is possible to reduce the total number of fastening members, by using the first common fastening member at the overlap section between the first flange and the second flange.

In the drive device for the vehicle that has the above configuration, the first case may further include an extension portion that extends between the motor case and the second flange, along an outer edge of the second case, from one end of the overlap section to the other end of the overlap section. The at least one common fastening member may include at least one second common fastening member that is positioned at the extension portion.

In the above configuration, the whole of the outer edge of the second case can be fastened by the first common fastening member and the second common fastening member.

In the drive device for the vehicle that has the above configuration, the average thickness of the second flange may be larger than the average thickness of the first flange.

Since the fastening member contacts with the second flange, a great force is applied to the second flange by the fastening member. In the above configuration, it is possible to cause the second flange to have a higher strength than the first flange, and therefore it is possible to restrain the breakage of the second flange.

In the drive device for the vehicle in the aspect of the present invention, motor may include a motor shaft. At least a part of the second case may overlap with the first case in a direction perpendicular to the central axis of the motor shaft.

In the above configuration, it is possible to decrease the protrusion amount of the second case in the central axis direction of the motor shaft. It is possible to reduce the physical size of the drive device.

In the drive device for the vehicle that has the above configuration, at least a part of the second case may overlap with the motor in a central axis direction of the motor shaft.

In the above configuration, it is possible to decrease the protrusion amount of the second case in the direction perpendicular to the central axis of the motor shaft. It is possible to reduce the physical size of the drive device.

In the drive device for the vehicle that has the above configuration, the second case may be disposed along a part of a circumference around the motor shaft, as viewed from the central axis direction of the motor shaft. The disposition range of the second case in the rotation direction of the motor may be <NUM>° or more around the motor shaft.

In the above configuration, it is possible to effectively utilize the space around the motor shaft.

In the drive device for the vehicle in the aspect of the present invention, the motor may include a motor shaft. Each of the plurality of fastening members may include a bolt. The longitudinal direction of the bolt may be roughly parallel to the central axis of the motor shaft.

In the drive device for the vehicle in the aspect of the present invention, the first case may constitute a first space that houses the gear unit, between the motor case and the first case.

In the drive device for the vehicle in the aspect of the present invention, the second case may constitute a second space that houses the electric power conversion unit, between the motor case and the second case.

The configuration of a drive device <NUM> for a vehicle will be described with reference to <FIG> is a sectional view showing a schematic configuration of the drive device <NUM> in an embodiment. The drive device <NUM> is an integrated device in which a motor, a gear unit, and an electric power conversion unit for controlling the motor are stored in an identical casing. Each of directions FR, RH and UP indicates the orientation of the drive device <NUM> with respect to the vehicle (battery electric vehicle) when the drive device <NUM> is installed in the vehicle. The direction FR indicates the forward direction of the front-rear direction of the vehicle. The direction RH indicates the rightward direction of the right-left direction (or the width direction) of the vehicle. The direction UP indicates the upward direction of the top-bottom direction of the vehicle. The same goes for the other figures. In <FIG>, a plurality of shafts (a motor shaft <NUM>, a countershaft <NUM>, and drive shafts <NUM>, 57R) are arranged and shown so as to be positioned on an identical plane.

The drive device <NUM> is controlled by a control device <NUM>. The control device <NUM> includes a CPU, a RAM, a ROM, input and output interfaces, and the like. The control device <NUM> is connected with an electric power conversion unit <NUM> and the like, by unillustrated signal lines.

The drive device <NUM> includes a casing <NUM>. The casing <NUM> includes a first case <NUM>, a second case <NUM>, and a motor case <NUM>. Each of the first case <NUM>, the second case <NUM>, and the motor case <NUM> may be a casting.

The motor case <NUM> includes a motor compartment <NUM>. In the motor compartment <NUM>, a motor <NUM> is stored. In other words, the motor case <NUM> houses the motor <NUM>. The motor <NUM> includes a stator <NUM>, a rotor <NUM>, and the motor shaft <NUM>. The stator <NUM> includes a cylindrical shape. In the interior of the stator <NUM>, the rotor <NUM> is disposed in a rotatable fashion. The motor shaft <NUM> has a central axis CA.

Further, the motor case <NUM> includes a facing surface <NUM> that faces the first case <NUM> and the second case <NUM>. On the facing surface <NUM>, a motor shaft hole MH and a drive shaft hole DH1 are formed. The motor shaft <NUM> passes through the motor shaft hole MH. The drive shaft <NUM> on the left side passes through the drive shaft hole DH1.

The first case <NUM> has a box shape in which one surface is opened. The first case <NUM> is fastened to the facing surface <NUM> such that the opening surface is closed by the facing surface <NUM>. The manner of the fastening will be described later. Thereby, a first space SP1 is constituted between the motor case <NUM> and the first case <NUM>. In the first space SP1, a gear unit <NUM> is stored. In other words, the first case <NUM> houses the gear unit <NUM>.

The gear unit <NUM> includes a shaft gear <NUM>, the countershaft <NUM>, a first counter gear <NUM>, a second counter gear <NUM>, a ring gear <NUM>, and a differential gear <NUM>. The shaft gear <NUM> is attached to the motor shaft <NUM>. Thereby, the gear unit <NUM> and the motor <NUM> are mechanically connected. The first counter gear <NUM> and the second counter gear <NUM> are attached to the countershaft <NUM>. The first counter gear <NUM> engages with the shaft gear <NUM>. The second counter gear <NUM> engages with the ring gear <NUM>. The ring gear <NUM> is attached to the differential gear <NUM>. The pair of the drive shafts <NUM>, 57R extends from the differential gear <NUM> in the vehicle-width direction. The drive shaft 57R passes through a drive shaft hole DH2 that is formed on the first case <NUM>. At a lower portion of the first space SP1, a retention portion <NUM> is included. In the retention portion <NUM>, oil <NUM> is retained. A part of the gear unit <NUM> is immersed in the oil <NUM> retained in the retention portion <NUM>.

The second case <NUM> has a box shape in which one surface is opened. The second case <NUM> is fastened to the facing surface <NUM> such that the opening surface is closed by the facing surface <NUM>. The manner of the fastening will be described later. Thereby, a second space SP2 is constituted between the motor case <NUM> and the second case <NUM>. In the second space SP2, the electric power conversion unit <NUM> is stored. In other words, the second case <NUM> houses the electric power conversion unit <NUM>. The electric power conversion unit <NUM> is a part for controlling the electric power that is supplied to the motor <NUM> and the electric power that is generated by the motor <NUM>. Examples of components that are included in the electric power conversion unit <NUM> include an inverter and a converter. The electric power conversion unit <NUM> is electrically connected with the motor <NUM> by a bus bar <NUM>.

Next, the configuration of the casing <NUM> will be described with reference to <FIG> and <FIG>. <FIG> shows a perspective view of the casing <NUM>. <FIG> is an exploded pan view of the casing <NUM>. In <FIG> and <FIG>, various components that are stored in the interior of the casing <NUM> are not illustrated. In <FIG>, the position of the motor shaft <NUM> is shown by a dotted line.

The first case <NUM> includes a first flange 11f that extends along an outer periphery of the first case <NUM>. In <FIG>, the first flange 11f is formed at an overlap section OS and a section SS. The second case <NUM> includes a second flange 12f that extends along the outer periphery of the second case <NUM>. The motor case <NUM> includes a motor case flange 13f that extends along the outer periphery of the motor case <NUM>. On the first flange 11f, a plurality of fastening holes <NUM> is disposed. On the second flange 12f, a plurality of fastening holes <NUM> is disposed. On the motor case flange 13f and the facing surface <NUM>, a plurality of fastening holes <NUM> is disposed.

As shown in <FIG>, a part of the first flange 11f includes the overlap section OS. The overlap section OS is an area where the second flange 12f laps over the first flange 11f. In other words, at the overlap section OS, the first flange 11f is positioned between the facing surface <NUM> of the motor case <NUM> and the second flange 12f.

Further, the first case <NUM> includes an extension portion <NUM> that extends from an end portion E1 of the overlap section OS to an end portion E2 of the overlap section OS. The extension portion <NUM> is a frame-shaped member that extends along an outer edge of the second case <NUM>. The extension portion <NUM> has the same thickness as the first flange 11f. The extension portion <NUM> is formed integrally with the first case <NUM>. On the extension portion <NUM>, a plurality of fastening holes <NUM> is disposed. A base having a closed ring shape is formed by the first flange 11f disposed at the overlap section OS and the extension portion <NUM>. An opening area OA is formed on the inside of the ring-shaped base. The ring-shaped base is formed so as to overlap with the second flange 12f over the whole periphery when the second case <NUM> is mounted. That is, the ring-shaped base functions also as a spacer ring.

The first case <NUM> and the second case <NUM> are fastened to the motor case <NUM> by a plurality of bolts <NUM>. The longitudinal direction of the plurality of bolts <NUM> is roughly parallel to the central axis CA of the motor shaft <NUM>. Specific descriptions will be made. The plurality of bolts <NUM> includes at least one first common bolt <NUM> that is disposed at the overlap section OS. In other words, at the position of the first common bolt <NUM>, the second case <NUM> is disposed on the first case <NUM>. At the overlap section OS, the fastening hole <NUM> of the second flange 12f, the fastening hole <NUM> of the first flange 11f, and the fastening hole <NUM> of the motor case <NUM> coincides with each other. The first common bolt <NUM> passes through the fastening hole <NUM> and the fastening hole <NUM>, and is inserted into the fastening hole <NUM>. Thereby, the first case <NUM> and the second case <NUM> are concurrently fastened to the motor case <NUM>.

Further, the plurality of bolts <NUM> include at least one second common bolt <NUM> that is disposed at an extension-portion section ES where the extension portion <NUM> exists. At the extension-portion section ES, the second common bolt <NUM> passes through the fastening hole <NUM> and the fastening hole <NUM>, and is inserted into the fastening hole <NUM>. Thereby, the extension portion <NUM> and the second case <NUM> are concurrently fastened to the motor case <NUM>. In other words, the extension portion <NUM> is positioned between the motor case <NUM> and the second flange 12f.

At the section SS of the first flange 11f, which is a section other than the overlap section OS, bolts <NUM> are disposed. At the section SS, each bolt <NUM> passes through the fastening hole <NUM>, and is inserted into the fastening hole <NUM> (see <FIG>). Thereby, the first case <NUM> is fastened to the motor case <NUM>.

The average thickness of the second flange 12f is larger than the average thickness of the first flange 11f. The effect will be described. The bolt contacts with the second flange 12f at the area where the first case <NUM> and the second case <NUM> are concurrently fastened to the motor case <NUM>. Accordingly, by the bolt, a greater force is applied to the second flange 12f than to the first flange 11f. Hence, the strength of the second flange 12f is set so as to be higher than the strength of the first flange 11f, and thereby it is possible to restrain the breakage of the second flange 12f.

Next, the position relation between the first case <NUM> and the second case <NUM> will be described with reference to <FIG> and <FIG>. As shown in <FIG>, at an area on the opposite side of the motor shaft <NUM> from the gear unit <NUM>, a space is formed due to a dimensional difference between the motor <NUM> and the gear unit <NUM>. In this space, the second case <NUM> is disposed. That is, at least a part of the second case <NUM> overlaps with the first case <NUM> in a direction D1 perpendicular to the central axis CA of the motor shaft <NUM>. Thereby, it is possible to effectively utilize the space around the motor shaft <NUM>. Consequently, it is possible to decrease the protrusion amount of the second case <NUM> in a central axis direction D2 of the motor shaft <NUM>. It is possible to reduce the physical size of the drive device <NUM>.

Further, at least a part of the second case <NUM> overlaps with the motor <NUM> in the central axis direction D2. This also makes it possible to effectively utilize the space around the motor shaft <NUM>. Consequently, it is possible to decrease the protrusion amount of the second case <NUM> in the direction D1 perpendicular to the central axis CA.

As shown in <FIG>, the second case <NUM> is disposed along a part of a circumference around the motor shaft <NUM>, as viewed from the central axis direction D2 of the motor shaft <NUM>. Moreover, the disposition range of the second case <NUM> in the rotation direction of the motor is <NUM>° or more around the motor shaft <NUM>. Thereby, it is possible to sufficiently secure the capacity of the second case <NUM>.

Next, effects of the drive device for the vehicle will be described. In a configuration in which a case is fastened using bolts, generally, it is necessary to secure a space such as a tool gap, around bolt fastening portions. As the number of bolt fastening portions is larger, the necessary space is larger, and therefore the capacity of the case is sometimes restricted. In the technology in the present specification, the first case <NUM> and the second case <NUM> can be concurrently fastened to the motor case <NUM>, using the first common bolt <NUM>, at the overlap section OS between the first flange 11f and the second flange 12f. Thereby, the total number of necessary bolts can be reduced, and therefore the necessary space for bolts can be reduced. It is possible to achieve the securement of the capacities of the first case <NUM> and the second case <NUM> and the reduction in the physical size of the drive device <NUM>.

In the case where the extension portion <NUM> does not exist, a level difference corresponding to the thickness of the first flange 11f is formed between the overlap section OS and the extension-portion section ES (see <FIG>). There is a risk that the level difference makes it hard to secure sealing property. In the technology in the present specification, since the extension portion <NUM> is included, it is possible to equalize the height between the overlap section OS and the extension portion section ES. It is possible to enhance the sealing property of the second case <NUM>.

In the technology in the present specification, it is possible to form the spacer ring by the first flange 11f and the extension portion <NUM>. Then, it is possible to cause the spacer ring to function as a cushion, and therefore it is possible to restrain the vibration of the second case <NUM>.

Next, modifications of the drive device for the vehicle in the embodiment will be described. As the position relation between the first case <NUM> and the second case <NUM>, various position relations may be adopted. For example, the second case <NUM> may be disposed on the first case <NUM>. In this case, the second space SP2 may be constituted between the first case <NUM> and the second case <NUM>. Also in such an aspect, by including the overlap section OS, it is possible to reduce the total number of necessary bolts.

The function of the first case <NUM> and the function of the second case <NUM> may be swapped. That is, the first case <NUM> may house the electric power conversion unit <NUM>, and the second case <NUM> may house the gear unit <NUM>.

The first case <NUM> may exclude the extension portion <NUM>. Further, the extension portion <NUM> may be a separate component from the first case <NUM>.

Claim 1:
A drive device (<NUM>) for a vehicle, comprising:
a motor case (<NUM>) configured to house a motor (<NUM>);
a first case (<NUM>) configured to house a gear unit (<NUM>) that is mechanically connected with the motor (<NUM>); and
a second case (<NUM>) configured to house an electric power conversion unit (<NUM>) that is electrically connected with the motor (<NUM>), characterized in that
the first case (<NUM>) and the second case (<NUM>) are fastened to the motor case (<NUM>) by a plurality of fastening members; and
the plurality of fastening members includes at least one common fastening member (<NUM>, <NUM>) that concurrently fastens the first case (<NUM>) and the second case (<NUM>) to the motor case (<NUM>).