JP2021195056A - Vehicular power transmission device - Google Patents

Abstract

To provide a vehicular power transmission device which enables improvement of workability of work of connecting wiring to a connection part or similar work while protecting the connection part when a vehicle drives on a bad road.SOLUTION: In a transmission 2, a lower end 11a of a front case 5 and a lower end 7a of a rear case 7 are located below a lower end 6a of a center case 6. A rear wall surface 5a of the front case 5 faces a front wall surface 7b of the rear case 7 in an anteroposterior direction. A valve body 12 is installed at a lower part of the front case 5, and a connector 13 is attached to the rear wall surface 5a of the front case 5 with its lower end 13a located at a position lower than the center case 6.SELECTED DRAWING: Figure 3

Description

The present invention relates to a vehicle power transmission device.

As an automatic transmission for a vehicle provided with a hydraulic pressure supply device for supplying hydraulic pressure to a friction element, the one described in Patent Document 1 is known.

The automatic transmission for vehicles described in Patent Document 1 detects the temperature of a case, an oil pan provided at the lower part of the case, a valve body housed in the oil pan, and oil stored in the oil pan. It is equipped with an oil temperature detector.

The oil temperature detector is electrically connected to the connector via a wire harness, which is provided at the top of the case.

Japanese Patent No. 6597433

When the automatic transmission for a vehicle is applied to an FR (front engine / rear drive) vehicle, the automatic transmission for the vehicle will be installed below the floor panel. In this case, the connector is located between the floor panel and the case.

For this reason, it is difficult to visually recognize the connector from below the vehicle, and it is difficult to access the connector from below, which deteriorates the workability of connecting the wiring to the connector and replacing the connector and wiring.

On the other hand, if the connector is installed at the bottom of the case, the connector can be easily seen from below and the connector can be easily accessed from below, which improves workability such as connecting wiring to the connector. Can be improved.

However, if the connector is installed at the bottom of the case, the connector may collide with an obstacle such as a rock and receive an excessive load when the vehicle travels on a rough road.

The present invention has been made by paying attention to the above circumstances, and is a vehicle power capable of improving workability such as work of connecting wiring to a connection portion while protecting the connection portion when the vehicle is traveling on a rough road. It is intended to provide a transmission device.

The present invention is a vehicle power transmission device having a case member, a hydraulic control component installed on the case member, and a connection portion electrically connected to the hydraulic control component, wherein the case member is a power transmission device for a vehicle. A first case, a second case installed behind the first case and connected to the first case, and a second case installed behind the second case and connected to the second case. The lower end of the first case and the lower end of the third case are located below the lower end of the second case, and the lower end of the first case is formed. The rear wall surface faces the front wall surface of the third case in the front-rear direction, and the hydraulic control component is installed in the lower part of the first case inside the first case, and the connection is made. The portion is characterized in that at least the lower end of the connecting portion is located at a position lower than that of the second case and is attached to the rear wall surface of the first case.

As described above, according to the present invention, it is possible to improve workability such as work of connecting wiring to the connection portion while protecting the connection portion when the vehicle travels on a rough road.

FIG. 1 is a left side view of a vehicle power transmission device according to an embodiment of the present invention. FIG. 2 is a bottom view of a vehicle power transmission device according to an embodiment of the present invention. FIG. 3 is an enlarged view of the center case of FIG. 1 and its surroundings. FIG. 4 is a cross-sectional view taken along the line in the IV-IV direction of FIG.

The vehicle power transmission device according to an embodiment of the present invention has a case member, a hydraulic control component installed on the case member, and a connection portion electrically connected to the hydraulic control component. In the device, the case member is installed behind the first case and the first case, and is installed behind the second case and the second case connected to the first case. It has a third case connected to the second case, the lower end of the first case and the lower end of the third case are located below the lower end of the second case, and the first case The rear wall surface faces the front wall surface of the third case in the front-rear direction, the hydraulic control component is installed at the lower part of the first case inside the first case, and the connection portion is at least. The lower end of the connection portion is located at a position lower than that of the second case and is attached to the rear wall surface of the first case.

As a result, the vehicle power transmission device according to the embodiment of the present invention can improve workability such as work of connecting wiring to the connection portion while protecting the connection portion when the vehicle travels on a rough road.

Hereinafter, a vehicle power transmission device according to an embodiment of the present invention will be described with reference to the drawings.
1 to 4 are views showing a vehicle power transmission device according to an embodiment of the present invention. In FIGS. 1 to 4, the up / down / front / rear / left / right directions are based on the vehicle power transmission device installed in the vehicle, the front / rear direction of the vehicle is the front / rear direction, and the left / right direction of the vehicle (the width direction of the vehicle) is the left / right direction. , The vertical direction of the vehicle (the height direction of the vehicle) is the vertical direction.

First, the configuration will be described.
In FIGS. 1 and 2, a transmission 2 is mounted on the vehicle 1, and the transmission 2 is installed vertically below the floor panel 1A of the vehicle 1 in a state of being connected to the engine 3. The vehicle 1 of this embodiment is an FR (front engine / rear drive) vehicle.

The transmission 2 includes a transmission case 4, and the transmission case 4 includes a front case 5, a center case 6, a rear case 7, and an extension case 8. The transmission 2 of the embodiment constitutes the power transmission device for a vehicle of the present invention, and the transmission case 4 constitutes the case member of the present invention.

An engine 3 as an internal combustion engine is connected to the front end of the front case 5 by a bolt (not shown). The engine 3 burns fuel and converts thermal energy into mechanical energy.

The center case 6 is installed behind the front case 5 and is connected to the center case 6 by a bolt 31A.

The rear case 7 is installed behind the center case 6 and is connected to the center case 6 by a bolt 31B. The extension case 8 is installed behind the rear case 7 and is connected to the rear case 7 by a bolt 31C.

That is, the front case 5, the center case 6, the rear case 7, and the extension case 8 are installed side by side in the front-rear direction from the front side to the rear side.

As shown in FIG. 4, a partition wall 6W is provided at the front end portion of the center case 6, and the space between the front case 5 and the space inside the center case 6 are partitioned by the partition wall 6W.

A torque converter (not shown), a friction clutch 20 (see FIG. 4), and a transmission mechanism (not shown) are housed inside the transmission case 4. The torque converter is a fluid coupling in which power is transmitted from the engine 3, and the speed change mechanism shifts and outputs the power (rotational speed) transmitted from the torque converter.

The friction clutch 20 is installed between the torque converter and the transmission mechanism in the front-rear direction, and transmits the power of the engine 3 to the transmission mechanism and cuts off transmission to the transmission mechanism.

In the transmission 2 of the present embodiment, the torque converter and the friction clutch 20 are housed in the front case 5, and the speed change mechanism is housed in the center case 6, the rear case 7, and the extension case 8.

As shown in FIG. 4, the speed change mechanism includes, for example, an input shaft 9 having a plurality of input gears (not shown) and a counter shaft 10 having a plurality of counter gears (not shown) that mesh with the input gears.

The speed change mechanism transmits the power of the engine 3 from the input shaft 9 to the counter shaft 10 via the input gear and the counter gear, and is transmitted from the counter shaft 10 to the differential device (not shown) via the output shaft (not shown). The input shaft 9 is rotatably supported by the partition wall 6W of the center case 6.

The torque converter is provided with a lockup clutch (not shown), and the lockup clutch transmits the power of the engine to the input shaft 9 without passing through a fluid when the oil for engaging the lockup clutch is supplied.

When the oil for releasing the lockup clutch is supplied, the lockup clutch transmits the power of the engine 3 to the input shaft 9 via the fluid.

As shown in FIG. 1, an oil pan 11 is provided in the lower portion of the front case 5, and the valve body 12 is housed in the oil pan 11 and oil is stored in the oil pan 11. A flange portion 11A is formed on the outer peripheral edge of the oil pan 11 (see FIG. 2).

An oil pan fastening portion 5C is formed in the lower portion of the front case 5, and the oil pan fastening portion 5C projects downward from the bottom wall 5c of the front case 5 so as to surround the periphery of the valve body 12. The flange portion 11A is fastened to the lower part of the oil pan fastening portion 5C by bolts 21.

The valve body 12 is fastened to the bottom wall 5c of the front case 5 by a bolt (not shown).

The space surrounded by the bottom wall 5c of the front case 5, the oil pan fastening portion 5C, and the oil pan 11 constitutes a valve body chamber, and the valve body 12 is installed in the valve body chamber. That is, the valve body 12 of this embodiment is installed in the lower part of the front case 5.

A breather chamber (not shown) is formed in the front case 5. The breather chamber is formed above the valve body chamber and communicates with the valve body chamber. A part of the valve body 12 is installed in the breather chamber.

The front case 5 and the oil pan 11 of the present embodiment constitute the first case of the present invention, and the center case 6 constitutes the second case of the present invention. The rear case 7 constitutes the third case of the present invention.

The valve body 12 includes a regulator (not shown), a lockup valve, an electromagnetic solenoid, and the like.

The valve body 12 regulates the pressure of the oil stored in the oil pan by the regulator. When the lockup valve is driven by the electromagnetic solenoid, the valve body 12 is switched by the lockup valve to select an oil passage for engaging the lockup clutch or an oil passage for releasing the lockup clutch (not shown).

When the lockup valve is driven by the electromagnetic solenoid and the oil passage for engaging the lockup clutch is selected, the oil regulated by the regulator is locked up through the oil passage for engaging the lockup clutch by an oil pump (not shown). Is supplied to. As a result, the lockup clutch is engaged, and the power of the engine 3 is transmitted to the input shaft 9 via the lockup clutch.

When the lockup valve is driven by the electromagnetic solenoid and the oil passage for releasing the lockup clutch is selected, the oil regulated by the regulator is supplied to the lockup clutch through the oil passage for releasing the lockup clutch by the oil pump. Will be done.

As a result, the lockup clutch is released, and the power of the engine 3 is transmitted to the input shaft 9 via the fluid. The valve body 12 of this embodiment constitutes the hydraulic control component of the present invention.

The outer diameters of the front case 5, the center case 6 and the rear case 7 are the largest in the front case 5, the smallest in the center case 6, the rear case 7 is smaller than the front case 5, and the outer diameter is larger than the center case 6.

As shown in FIGS. 1 and 3, the lower end 11a of the oil pan 11 and the lower end 7a of the rear case 7 are located below the lower end 6a of the center case 6.

As shown in FIG. 3, the oil pan 11 covers the entire lower surface of the front case 5, and the lower end 11a of the oil pan 11 of the present embodiment constitutes the lower end of the first case of the present invention. Hereinafter, the lower end 11a of the oil pan 11 is referred to as the lower end 11a of the front case 5.

The rear wall surface 5a of the front case 5 faces the front wall surface 7b of the rear case 7 in the front-rear direction. The rear wall surface 5a of the front case 5 includes the rear wall surface 5a of the front case 5 and the rear wall surface of the oil pan 11.

A connector 13 is attached to the front case 5. The lower end 13a of the connector 13 is located at a position lower than the lower end 6a of the center case 6, and is attached to the rear wall surface 5a of the front case 5. The lower end 13a of the connector 13 constitutes the lower end of the connection portion of the present invention. The connector 13 may be located at a position lower than the lower end 6a of the center case 6 as a whole.

The connector 13 is connected to the valve solenoid of the valve body 12 via the wire harness 16 and is electrically connected to the valve body 12 via the wire harness 16.

A connector of an external wire harness (not shown) is connected to the connector 13. The external wire harness is connected to a control circuit such as an ECM (Engine Control Module) (not shown), and the valve body 12 is controlled by the control circuit. The connector 13 of this embodiment constitutes the connection portion of the present invention.

As shown in FIGS. 2 and 3, the center case 6 has a bulging portion 6A. The bulging portion 6A bulges toward the connector 13 from the front wall surface 7b side of the rear case 7 facing the connector 13 in the front-rear direction.

A parking lock mechanism is housed in the rear case 7, and a part of the parking lock mechanism is housed in the bulging portion 6A.

The center case 6 has a protrusion 6B. The protruding portion 6B protrudes downward from the lower end 6a of the center case 6 so as to face the connector 13 in the front-rear direction, and the lower end 6u in the protruding direction is the rear lower end 5u of the oil pan 11, that is, the rear portion of the front case 5. It is located below the lower end 5u.

As shown in FIG. 4, the connector 13 is installed at a position overlapping the center case 6 in the width direction of the vehicle 1 (hereinafter, simply referred to as the vehicle width direction), and the lower end 11a of the front case 5 and the center case are installed in the vertical direction. It is installed between 6.

The center case 6 has a rib 6C. The rib 6C projects outward (to the left) in the vehicle width direction from the outer peripheral wall 6b of the center case 6 located above the connector 13, and covers the upper part of the connector 13.

As shown in FIGS. 1 and 3, a shift case 14 is attached to the upper part of the center case 6, and a shift and select shaft 15 is housed in the shift case 14. The shift-and-select shaft 15 extends in the vehicle width direction, and is supported by the shift case 14 so as to be rotatable and axially movable.

The shift-and-select shaft 15 selectively operates a shift yoke for shifting (not shown), and the shift-and-select shaft 15 selectively operates a shift yoke (not shown), and the shift and select shaft 15 can rotate relative to the input shaft 9 and a predetermined shift through a shift shaft, a shift fork, and a synchronization device (not shown). An input gear capable of forming a stage is connected to the input shaft 9.

When an input gear capable of establishing a predetermined shift is connected to the input shaft 9, the power of the engine 3 is transmitted to the counter shaft 10 via the input gear, the synchronization device, the input shaft 9, and the counter gear.

As shown in FIG. 3, the length L1 in the front-rear direction of the shift case 14 is formed to be slightly shorter than the length L2 in the front-rear direction of the center case 6, and is the length in the front-rear direction of the shift case 14. The length L2 of the L1 and the center case 6 in the front-rear direction are about the same length. The term "same degree" as used herein includes the case where the length L1 in the front-rear direction of the shift case 14 and the length L2 in the front-rear direction of the center case 6 are the same.

Since the shift and select shaft 15 of this embodiment is installed on the upper part of the center case 6 so that the axial direction extends in the vehicle width direction, the length in the front-rear direction of the shift case 14 attached to the upper part of the center case 6 Can be shortened.

Therefore, the length of the center case 6 in the front-rear direction can be made shorter than the length of the front case 5 and the rear case 7 in the front-rear direction, and the outer diameter of the center case 6 can be made smaller than the outer diameters of the front case 5 and the rear case 7.

As shown in FIG. 3, the rear end 11r of the flange portion 11A of the oil pan 11 projects from the rear wall surface 5a of the front case 5 toward the front wall surface 7b of the rear case 7. The distance L3 in the front-rear direction between the front surface 6f of the protrusion 6B and the rear end 11r of the flange portion 11A of the oil pan 11 is smaller than the front-rear length L1 of the shift case 14 and the front-rear length L2 of the center case 6. It has become. Specifically, the relationship is L2> L1> L3.

Next, the effect of the transmission 2 of this embodiment will be described.
The transmission 2 of the present embodiment has a transmission case 4, and the transmission case 4 is installed behind the front case 5, the oil pan 11 connected to the lower part of the front case 5, and the front case 5. It has a center case 6 connected to the front case 5 and a rear case 7 installed behind the center case 6 and connected to the center case 6.

The lower end 11a of the front case 5 and the lower end 7a of the rear case 7 are located below the lower end 6a of the center case 6, and the rear wall surface 5a of the front case 5 faces the front wall surface 7b of the rear case 7 in the front-rear direction. ing.

In addition to this, the valve body 12 is installed in the lower part of the front case 5, and the connector 13 is attached to the rear wall surface 5a of the front case 5 with the lower end 13a located at a position lower than the center case 6. There is.

As a result, the connector 13 can be easily visually recognized from below the vehicle 1, and the connector 13 can be easily accessed from below. Therefore, workability such as work of removing the oil pan 11 from the front case 5 to maintain the valve body 12 and work of replacing or maintaining the wire harness 16 can be improved.

In addition to this, workability such as replacement of the connector 13, connection of the connector of the external wire harness to the connector 13, or replacement of the external wire harness can be improved.

Further, the connector 13 can be installed in the constricted portion of the transmission case 4, that is, in the space 18 surrounded by the rear wall surface 5a of the front case 5, the lower end 6a of the center case 6, and the front wall surface 7b of the rear case 7.

Therefore, when the vehicle 1 is traveling on a rough road, the obstacles are caused by colliding with the lower end 11a of the front case 5 and the lower end 7a of the rear case 7 before the obstacles such as rocks and stepping stones on the road interfere with the connector 13. Interference with the connector 13 can be suppressed, and external force can be prevented from being applied to the connector 13. Therefore, the connector 13 can be protected.

Further, according to the transmission 2 of the present embodiment, the center case 6 has a bulging portion 6A, and the bulging portion 6A is a connector 13 from the front wall surface 7b side of the rear case 7 facing the connector 13 in the front-rear direction. It bulges toward.

As a result, as shown in FIG. 2, when the transmission 2 is viewed from below, the gap in the front-rear direction between the bulging portion 6A and the rear wall surface 5a of the front case 5 is reduced, and the connector 13 is installed. Space 18 can be narrowed.

Therefore, it is possible to more effectively suppress the interference of obstacles with the connector 13, and it is possible to more effectively protect the connector 13.

In addition to this, the bulging portion 6A can improve the rigidity of the front wall surface 7b of the rear case 7, and the bulging portion 6A can improve the rigidity of the lower end 7a of the rear case 7 continuous with the front wall surface 7b.

That is, the rigidity of the lower end 7a of the rear case 7 on the front wall surface 7b side, which is more likely to interfere with obstacles than the connector 13 because it is located below the connector 13, can be improved by the bulging portion 6A.

Therefore, when an obstacle collides with the lower end 7a of the rear case 7, the lower end 7a of the rear case 7 on the front wall surface 7b side is suppressed from being deformed, and the obstacle interferes with the connector 13 more effectively. It can protect the connector 13 more effectively.

Further, according to the transmission 2 of the present embodiment, the rear case 7 has a protruding portion 6B, and the protruding portion 6B projects downward from the lower end 6a of the center case 6 so as to face the connector 13 in the front-rear direction. The lower end 6u in the protruding direction is located below the rear lower end 5u of the front case 5.

As a result, when the vehicle 1 is traveling on a rough road, it is possible to more effectively prevent the obstacle from colliding with the protrusion 6B before the obstacle collides with the connector 13 and the obstacle from interfering with the connector 13, and the connector 13 is more effective. Can be protected.

In addition to this, the protrusion 6B can improve the rigidity of the front wall surface 7b of the rear case 7, and the protrusion 6B can improve the rigidity of the lower end 7a of the rear case 7 continuous with the front wall surface 7b.

That is, the rigidity of the lower end 7a of the rear case 7 on the front wall surface 7b side, which is more likely to interfere with obstacles than the connector 13 by being located below the connector 13, can be improved by the protrusion 6B.

Therefore, when an obstacle collides with the lower end 7a of the rear case 7, the lower end 7a of the rear case 7 on the front wall surface 7b side is suppressed from being deformed, and the obstacle interferes with the connector 13 more effectively. It can protect the connector 13 more effectively.

Further, according to the transmission 2 of the present embodiment, the connector 13 is installed at a position overlapping the center case 6 in the vehicle width direction and between the lower end 11a of the front case 5 and the center case 6 in the vertical direction. There is.

As a result, the connector 13 can be installed on the center side in the vehicle width direction of the space 18 surrounded by the rear wall surface 5a of the front case 5, the lower end 6a of the center case 6, and the front wall surface 7b of the rear case 7.

Therefore, the obstacle interferes with the connector 13 by colliding the obstacle with the lower end 11a of the front case 5 and the lower end 7a of the rear case 7 before the obstacle interferes with the connector 13 when the vehicle 1 is traveling on a rough road. This can be suppressed more effectively, and the connector 13 can be protected more effectively.

Further, since the upper part of the connector 13 can be covered by the center case 6, the water W (see FIG. 4) dripping from the upper part of the transmission case 4 below the floor panel 1A when traveling in the rain or the like can be collected from the center case 6. It can be blocked by and prevented from reaching the connector 13. Therefore, it is possible to prevent the connector 13 from being exposed to water and protect the connector 13 from water.

Further, according to the transmission 2 of the present embodiment, the center case 6 has a rib 6C, and the rib 6C protrudes outward in the vehicle width direction from the outer peripheral wall 6b of the center case 6 located above the connector 13. , Covers the top of the connector 13.

As a result, the upper part of the connector 13 can be covered by the rib 6C, so that the water W dripping from above the transmission case 4 below the floor panel 1A is blocked by the rib 6C when traveling in the rain (see FIG. 4). ), It is possible to more effectively suppress reaching the connector 13. Therefore, it is possible to prevent the connector 13 from being exposed to water and protect the connector 13 from water.

Further, according to the transmission 2 of the present embodiment, a shift case 14 accommodating a shift and select shaft 15 extending in the vehicle width direction is attached to the upper part of the center case 6, and the length of the center case 6 in the front-rear direction. L2 is formed to have a length similar to the length L1 in the front-rear direction of the shift case 14.

As a result, the length of the shift case 14 attached to the upper part of the center case 6 in the front-rear direction can be shortened, and the length of the center case 6 in the front-rear direction can be made shorter than the length of the front case 5 and the rear case 7 in the front-rear direction.

Therefore, the gap between the rear wall surface 5a of the front case 5 and the front wall surface 7b of the rear case 7 in the front-rear direction can be further reduced, and the space 18 in which the connector 13 is installed can be further narrowed.

As a result, it is possible to more effectively suppress the interference of obstacles with the connector 13, and it is possible to more effectively protect the connector 13.

Further, according to the transmission 2 of the present embodiment, since the rear end 11r of the flange portion 11A of the oil pan 11 protrudes from the rear wall surface 5a of the front case 5 toward the front wall surface 7b, a part of the lower portion of the connector 13. Can be covered by the flange portion 11A.

Therefore, the flange portion 11A can prevent an obstacle from colliding with the connector 13, and the connector 13 can be protected more effectively.
The vehicle power transmission device of this embodiment is applied to a transmission, but is not limited to the transmission.

Although embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

1 ... vehicle, 2 ... transmission (power transmission device for vehicle), 4 ... transmission case (case member), 5 ... front case (first case), 5a ... rear Wall surface (rear wall surface of the first case), 5u ... rear lower end (rear lower end of the first case), 6 ... center case (second case), 6A ... bulging part, 6a. .. Lower end (lower end of second case), 6B ... protrusion, 6b ... outer wall (outer wall of second case), 6C ... rib, 7 ... rear case (third) Case), 6u ... lower end (lower end in the protruding direction of the protrusion), 7a ... lower end (lower end of the third case), 7b ... front wall surface (front wall surface of the third case), 11. .. Oil pan (first case), 11a ... lower end (lower end of first case), 12 ... valve body (hydraulic control component), 13 ... connector (connection part), 13a .. .Lower end (lower end of connection), 14 ... shift case, 15 ... shift and select axis

Claims (6)

A vehicle power transmission device having a case member, a hydraulic control component installed on the case member, and a connection portion electrically connected to the hydraulic control component.
The case member is installed behind the first case, the first case, and is connected to the first case, and is installed behind the second case, and the first case is described. It has a third case connected to the second case and
The lower end of the first case and the lower end of the third case are located below the lower end of the second case.
The rear wall surface of the first case faces the front wall surface of the third case in the front-rear direction.
The hydraulic control component is installed in the lower part of the first case inside the first case.
The vehicle power transmission device is characterized in that at least the lower end of the connection portion is located at a position lower than that of the second case and is attached to the rear wall surface of the first case. The second case has a bulge and
The vehicle power according to claim 1, wherein the bulging portion bulges from the front wall surface side of the third case facing the connecting portion in the front-rear direction toward the connecting portion. Transmission device. The second case has a protrusion and has a protrusion.
The protruding portion protrudes downward from the lower end of the second case so as to face the connecting portion in the front-rear direction, and the lower end in the protruding direction is located below the lower end of the rear portion of the first case. The vehicle power transmission device according to claim 1 or 2. The connection portion is characterized in that it is installed at a position overlapping the second case in the width direction of the vehicle and between the lower portion of the first case and the second case in the vertical direction. The vehicle power transmission device according to any one of claims 1 to 3. The second case has ribs and
The fourth aspect of claim 4, wherein the rib protrudes outward in the width direction of the vehicle from the outer peripheral wall of the second case located above the connection portion and covers the upper portion of the connection portion. Power transmission device for vehicles. A shift case for accommodating a shift-and-select shaft extending in the vehicle width direction is attached to the upper part of the second case.
The method according to any one of claims 1 to 5, wherein the length of the second case in the front-rear direction is formed to be the same length as the length of the shift case in the front-rear direction. The vehicle power transmission device described.

Images