JPH0316834A - Four-wheel drive car for horizontally-mounted engine type - Google Patents

Abstract

PURPOSE:To position a steering shaft and an exhaust pipe to a direction of shifting gear and a propeller shaft and in the vicinity of both sides thereof and to effectively lay out the two members in a position near a central part in the direction of width by a method wherein the steering shaft and the exhaust pipe are arranged in a manner to pass the both sides of the direction shifting gear with the direction shift gear nipped therebetween. CONSTITUTION:A steering shaft 21 and an exhaust pipe 22 extending through a position below a part, where an engine 2 and a transmission 6 are arranged, and longitudinally of a vehicle are arranged in a manner to respectively extend both sides of each of the shaft and the exhaust pipe around a direction shifting gear 12. This constitution arranges three members of a propeller shaft connected to the direction shifting gear 12, steering shafts 21 positioned on both sides thereof, and the exhaust pipe 22 in a manner to approach each other and in a position near a central part in the direction of width.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention has an engine and a transmission placed horizontally at the front of a vehicle, and a front wheel differential device located at the front of the vehicle with respect to the engine. This article relates to a four-wheel drive vehicle in which the drive system is arranged so that the direction conversion gear is located on the rear side of the vehicle, and particularly relates to the layout 1 of the steering shaft and exhaust pipe in such a four-wheel drive vehicle. .

[Conventional technology]

Conventionally, as shown in Japanese Patent Application Laid-Open No. 63-103735, an engine and a transmission are mounted horizontally in an engine room at the front of a vehicle, and a front wheel differential device and a front wheel axle are connected. Direction conversion gear that transmits power in the direction of the propeller shaft (4-wheel drive power extraction gear)
The vehicle is equipped with a drive system for four-wheel drive, and is laid out so that the front wheel differential is located in front of the vehicle with respect to the engine, and the direction conversion gear is located in the rear of the vehicle. Four-wheel drive vehicles are known.

According to this layout of the engine, transmission, and drive system, the engine is located toward the rear of the vehicle relative to the front axle, which is connected to the front differential, so most of the engine and power transmission mechanism are connected to the front axle. Compared to the case where the front wheel is located further forward, the load on the front wheels is reduced, and the turning performance, steering performance, etc. of the vehicle are improved. Furthermore, by locating the direction conversion gear on the rear side of the vehicle relative to the front wheel differential, the layout becomes convenient for connection with the propeller shaft 1 to the like.

In the mechanism disclosed in the above publication, the transmission is arranged in parallel in front of the engine, but a mechanism in which the engine and the transmission are arranged in series in the vehicle width direction is also known.

(Problems to be Solved by the Invention) By the way, in the structure shown in the above publication, the steering mechanism is arranged below the engine behind the axle, but when the engine is located behind the axle, In order to provide the steering mechanism close to the axle while avoiding interference with the oil van at the lower end of the engine and reducing ground clearance, it is advantageous to locate the steering mechanism in front of the axle. In this case, the steering shaft connected to the steering mechanism is
Is it necessary to place it so that it extends back and forth under the area where the engine and transmission are located? becomes. For example, when a V-type engine is installed horizontally, the exhaust pipe that guides exhaust from the front bank of the engine is arranged to extend from the front of the axle to the rear across the axle. The exhaust pipe also passes below the area where the engine and transmission are located and extends back and forth.

In a four-wheel drive vehicle in which the drive system is arranged as described above for the engine and transmission, the steering shaft and exhaust pipe are arranged so as to extend back and forth passing below the engine and transmission. In this case, the steering shaft and exhaust pipe cross the area where the drive system is installed, so it is necessary to lay out the drive system so that the steering shaft and exhaust pipe do not interfere with each other. Furthermore, in terms of power transmission to the rear wheels, it is desirable to position the propeller shaft connected to the direction conversion gear in the drive system near the center in the vehicle width direction. For these reasons, it is desirable to place the steering shaft and exhaust pipe closer to the center in the vehicle width direction. However, from these points, problems remain with the layout of the drive system, steering shaft, and exhaust pipe.

In view of these circumstances, the present invention has developed a drive system in which a front wheel differential is located at the front and side of the vehicle with respect to a horizontally mounted engine, and a direction conversion gear is located at the rear of the vehicle. When the steering shaft and exhaust pipe are arranged so that they extend forward and backward passing below the engine and transmission, the propeller shaft and steering To provide a transverse engine type four-wheel drive vehicle in which a shaft and an exhaust pipe can be effectively laid out closer to the center in the vehicle width direction.

[Means to solve the problem]

In order to achieve the above-mentioned object, the first invention mounts an engine and a transmission horizontally at the front of a vehicle, and also transmits power toward a front wheel differential device to which the front wheel axle is connected and a propeller shaft. A four-wheel drive system in which a direction conversion gear for transmitting 6 is arranged such that the front wheel differential is located on the front side of the vehicle with respect to the engine, and the direction conversion gear is located on the rear side of the vehicle. In a car, a steering mechanism is arranged on the front side of the vehicle with respect to the axle, and a steering shaft is connected to the steering mechanism and extends in the longitudinal direction of the vehicle. The steering shaft and the exhaust pipe are arranged to pass on both sides of the direction conversion gear, with the steering shaft interposed therebetween.

In addition, the second invention has an engine and a transmission mounted horizontally at the front of the vehicle, and a front wheel differential device to which the front wheel axle is connected and a direction conversion gear that transmits power in the direction of the propeller shaft. In a four-wheel drive vehicle in which the front wheel differential is located in front of the engine and the direction conversion gear is located in the rear of the vehicle, the steering mechanism is located closer to the axle. is arranged at the front side of the vehicle, and includes a steering shaft connected to the steering mechanism and extending in the longitudinal direction of the vehicle, and an engine exhaust pipe extending from the front of the axle to the lower side of the axle to the rear side of the vehicle, The above-mentioned steering shaft and the above-mentioned exhaust pipe are arranged side by side at a position that passes through the side opposite to the side where the transmission is located with respect to the direction change gear.

[Effect]

According to the structure of the first invention, the steering shaft and the exhaust pipe, which extend in the longitudinal direction of the vehicle passing below the portion where the engine and the transmission are arranged, respectively extend from both sides of the steering shaft while avoiding the direction changing gear. By arranging it so that it passes through the propeller shaft, the propeller shaft connected to the direction conversion gear, the steering shaft and the exhaust pipe located on both sides of the propeller shaft can be placed close to each other and closer to the center in the vehicle width direction. becomes.

Also according to the structure of the second invention, the steering shaft and the exhaust pipe are arranged close to each other on one side of the direction conversion gear while avoiding the direction conversion gear. It is now possible to arrange the three parts of the gearbox and the gear shaft close to each other and closer to the center in the vehicle width direction, and this second invention is advantageous when there is little space below the transmission. The steering shaft and exhaust pipe are placed in a position that avoids the transmission.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

1 to 3 show a first embodiment of the present invention.

In the plan view of Fig. 1, the bottom side of the figure is the front side of the vehicle (the same applies to Figs. 5, 7, and 10 described later), and in the side view of Fig. 3, the left side of the figure is the front side of the vehicle (described later). The same applies to Figures 9 and 12, and Figure 2 shows the engine, drive system, etc. seen from the front of the vehicle (Figures 6 and 8, which will be described later).
The same applies to FIG.

In these figures, 1 is the engine room at the front of the vehicle,
2 is an engine installed in engine room 1,
The engine 2 is disposed horizontally 9 with respect to the vehicle, that is, the engine output shaft is disposed so as to extend in the vehicle width direction. The engine 2 shown in the figure is a ■-type engine, has a pair of banks 3.4 arranged in front and behind, and is installed in a state inclined slightly forward. An oil bun 5 is attached to the lower end of the engine 2. Further, a transmission Ia6 having a well-known transmission mechanism is connected to the engine 2 within a mission case 6a, and this transmission 6 is also arranged horizontally. In the example shown in the figure, the right side as seen from the driver's seat (the left side in the drawings of Figures 1 and 3)
Engine 2 is located on the left side when viewed from the driver's seat.
A transmission 6 is connected in series to the engine 2 in such a manner that the engine 2 is located in the engine 2.

A pair of front wheel axles 7 are connected to the left and right front wheels 8, are connected to both sides of a front differential (front wheel differential @) 9, and extend in the vehicle width direction through the lower part of the engine room 1. . The above-mentioned front wheel differential 9 and the front wheel axle 7 are arranged on the front side of the vehicle with respect to the engine 2 and the transmission 6. In other words, most of the engine 2 and the transmission 6 are located 10 degrees behind the axle 7 directly above it. It is arranged like this. The reason for this arrangement is to reduce the load on the front wheels and improve the maneuverability and steering performance when the vehicle turns. A housing portion 10 that accommodates the front differential 9 is attached to the mission case 6 in a state of protruding forward from the lower part of the mission case 6a.
It is integrally connected to a.

In addition, a center differential (intermediate differential) 11 that distributes the power transmitted from the transmission 6 between the front wheels and the rear wheels is disposed at the rear of the lower part of the mission case 6a. A direction conversion gear 12 to which a power transmission portion to the rear wheels is connected is disposed at a position on the rear side of the vehicle with respect to the engine 2. As will be described in detail later, on one output side of the center differential 11, a shaft 13 extending forward is connected to a pair of bevel gears 14a. 14b, and the input side of the front differential 9 is connected to this shaft 13 via a pair of bevel gears 15a, 15b, and the other output side of the center differential 11 is connected to the side through the center differential 11. A shaft 16 extending from 11 to 11 is connected, and the direction changing gear 12 is equipped at the end of this shaft 16.

The direction changing gear 12 is a pair of bevel gears 12a, 12.
b, and a propeller shaft 17 is connected to its output side. The propeller shaft 17 extends toward the rear of the vehicle and is connected to a rear differential (not shown) at the rear of the vehicle.

The direction conversion gear 12 and propeller shaft 17 are
In order to effectively transmit power to the rear wheels, it is disposed so as to pass approximately through the widthwise center of the vehicle. Note that when the drive system has a concrete structure as shown in FIG. 4, which will be described later, the direction conversion gear 12 is arranged approximately at the center in the vehicle width direction.
The center differential 11 is located at the rear of the lower part of the transmission case 6a at a position biased to one side in the vehicle width direction, and the front differential 9 is also located at the lower part on the front side of the vehicle at a position slightly to one side from the center in the vehicle width direction. It is installed in a biased position.

Reference numeral 20 denotes a steering mechanism, and since most of the engine 2 and transmission 6 are located behind the axle 7, the steering mechanism 20 is designed to steer the axle while avoiding interference with the oil pan 5 of the engine 2, etc. 7, it is placed in front of the axle 7. A steering shaft 21 whose front end is connected to the steering mechanism 20 extends in the longitudinal direction of the vehicle passing below the axle 7, and whose rear end is connected to a steering wheel (not shown) via a joint or the like.

Furthermore, exhaust manifolds 22a. The front exhaust pipe 22 and the rear exhaust pipe 23 are connected to each other via 23a. The front exhaust pipe 22 extends from the front side of the axle 7 to the rear side of the vehicle through the underside of the axle 7, and is assembled with the rear exhaust pipe 23 at the rear of the axle 7, and is a common exhaust downstream of the collection part. The pipe 24 extends to the rear end of the vehicle.

The steering shaft 21 and the front exhaust pipe 22
are arranged at positions passing on both sides of the direction changing gear 12 with the direction changing gear 12 interposed therebetween. To explain specifically the arrangement of these in this embodiment, the steering shaft 21 has a rear portion that is connected to the shaft on the side of the transmission 6 (on the right side in FIGS. 1 and 2) with respect to the direction conversion gear 12. 1
6, and the front portion thereof is positioned closer to the center in the vehicle width direction than the front differential 10, and is arranged so as to pass below the axle 7.

On the other hand, the front exhaust pipe 22 is disposed on the side opposite to the steering shaft 21 (the left side in FIGS. 1 and 2) with respect to the direction conversion gear 12, and is arranged so as to pass below the engine 2. There is.

According to this first embodiment, the steering shaft 2 is
1 and a front exhaust pipe 22 are arranged to pass through each of the above spaces.

As a result, the steering shaft 21 and the front exhaust pipe 22 pass through positions 14 on both sides of the direction conversion gear 12 close to the direction conversion gear 12, while avoiding interference with the direction conversion gear 12 of the drive system, the front differential 9, etc. It happens. Therefore, the propeller shaft i~17 connected to the direction conversion gear 12, the steering shaft 21, and the front exhaust pipe 22 are close to each other and pass near the center in the vehicle width direction, thereby improving power transmission to the rear wheels and steering. The layout is advantageous in terms of force transmission, exhaust ventilation, etc.

In addition, if the steering shaft 21 or the front exhaust pipe 2
If the steering shaft 21 and the front exhaust pipe 22 are arranged so as to pass below the direction change gear 12 etc., the ground clearance will be reduced and this is not favorable for vehicle running. It is also advantageous to secure ground clearance as it passes through the ground.

FIG. 4 shows an example of a specific structure of the drive system.

In this figure, the front differential 9 located at the front of the lower part of the mission case 6a is composed of a differential case 9a rotatably supported by a housing portion 10, a pinion gear 9b, a side gear 90, etc., and each of the left and right front wheels is connected to both side gears 9C. The axle 7 is connected to the differential case 9a, and a bevel gear 1155b is fixed to the differential case 9a. The center differential 11 located at the rear of the lower part of the mission case 6a is composed of a differential case 11a rotatably supported by the mission case 6a, a pinion gear 11b, a side gear 11C, etc., and a gear 26 fixed to the differential case 11a changes gears. This center differential meshes with the machine's output gear (not shown).
A shaft 16 extending in the vehicle width direction passes through the center of the center differential 11, and a cylindrical shaft 27 provided with a bevel gear 14a is rotatably installed around the shaft 16 on the side of the center differential 11. One side gear 11
The cylindrical shaft 27 is connected to c, and the shaft 16 is connected to the other side gear 11G.

The cylinder shaft 27 has a shaft 13 extending forward and a bevel gear 14a provided on both sides. 14b, and the differential case 9a of the front differential 9 is connected to the front end of the shaft 13 by bevel gears 15a. 15
connected by b. Furthermore, one bevel gear 12a of the direction conversion gear 12 is attached to the end 16 of the shaft 16 extending in the vehicle width direction, and the propeller shaft 17 is connected to the bevel gear 12b that meshes with the bevel gear 12a. There is.

In the case of such a specific structure of the drive system, the front differential 9, the center differential 11, and the direction conversion gear 12 are the same as the first one described above.
The arrangement is as shown in FIGS. In the second to fourth embodiments to be described later, the arrangement of the front differential 9, center differential 11, direction conversion gear 12, etc. shown in the drawings is based on the specific structure shown in FIG. 4.

5 and 6 show a second embodiment.

In this embodiment as well, the steering shaft 21 and the front exhaust pipe 22 are arranged to pass on both sides of the direction conversion gear 12, but the positional relationship between the steering shaft 21 and the front exhaust pipe 22 is This is the opposite of the first embodiment. That is, the front exhaust pipe 22 is located on the side of the transmission 6 (the right side in FIGS. 5 and 6) with respect to the direction conversion gear 12, and the front exhaust pipe 22 is located on the side opposite to the front exhaust pipe 22 (the right side in FIGS. 5 and 6). , 17) The steering shaft 21 is located on the side (left side in FIG. 6).

For example, in a right-hand drive vehicle, etc., if it is advantageous to position the steering shaft 21 laterally on the engine side than the propeller shaft 17 for reasons of connection with the steering wheel, the second embodiment may be used. It may be a layout.

Further, if it is advantageous to position the exhaust system laterally on the engine side than the propeller shaft 17 in order to prevent interference with the fuel tank or the like, the layout as in the first embodiment may be used.

7 to 9 show a third embodiment.

In these figures, a sub-frame 32 is provided inside each frame 31 provided on both sides of the vehicle, and has a vertical member connected to a cross member (not shown) on which a steering mechanism is mounted. The subframe 32 passes under the axle 7. This subframe 3
2, the front exhaust pipe 22 is arranged so as to pass through the inside of one of the subframes 32, and is connected to the transmission 6 on the side of the front differential 9, for example.
It is arranged to pass through the inside of the subframe 32 located below. On the other hand, the steering shaft 21 is
It is arranged so as to pass through one side of the direction conversion gear 12,
For example, it is arranged so as to pass on the side opposite to the side where the front differential 32 and the transmission 6 are located (engine side). The structure and arrangement of other parts are the same as in the first embodiment.

According to this embodiment, the front differential 9, the direction conversion gear 1
The front exhaust pipe 22 can be effectively installed while avoiding interference with the second class.
and steering shaft 21 are arranged, and in addition to achieving effects such as securing ground clearance, the exhaust pipe 22
Since the heat radiated from the subframe 32 is blocked by the subframe 32, the effect of preventing heat damage can also be obtained.

10 to 12 show a fourth embodiment. In this embodiment, both the steering shaft 21 and the front exhaust pipe 22 are located on the side of the direction conversion gear 12 opposite to the side where the transmission 6 is located (the engine 19 side), and the axle shaft 7 and are arranged close to each other in a position passing below the engine 2. The positional relationship between the steering shaft 21 and the front exhaust pipe 22 is as follows:
The left and right sides may be reversed from the illustrated example. The structure and arrangement of other parts are the same as in the first embodiment.

Also in this embodiment, a steering shaft 21 is provided at a position on one side of the direction changing gear 12 and close to it.
By arranging the front exhaust pipes 22 side by side, the propeller shaft 17, the steering shaft 21, and the front exhaust pipe 22 are close to each other and pass near the center in the vehicle width direction, thereby transmitting power to the rear wheels. The layout is advantageous in terms of transmission, steering force transmission, exhaust exhaust, etc. In particular, this layout is designed so that both the steering shaft 21 and the front exhaust pipe 22 are connected to each other due to reasons such as connection between the steering shaft 21 and the steering wheel as described above, and prevention of interference between the exhaust pipe and the fuel tank. This may be adopted in cases where it is advantageous to locate the direction conversion gear 12 on the side closer to the engine. Also, j shift l! Even when there is little space below the gear 16, the arrangement of this embodiment allows the steering shaft 21 and the front exhaust pipe 22 to be effectively moved while avoiding interference with the direction changing gear 12 and the transmission 6. It will be laid out.

However, in this embodiment, the steering shaft 2
Since both the steering shaft 21 and the front exhaust pipe 22 are located laterally on the engine 2 side than the direction conversion gear 12, the oil pan 5 attached to the lower part of the engine 2 is connected to the steering shaft 21 and the front exhaust pipe 22. The size in the vehicle width direction is limited to avoid interference. Therefore, as shown in FIG. 12, the rear part of the oil pan 5 is shaped to protrude further back than the engine 2, and the capacity of the oil pan 5 is secured by this protruding portion 5a. is desirable.

In addition, the front of the vehicle with respect to engine 2. The specific structure of the drive system in which the front differential is arranged on the side and the direction conversion gear is arranged on the rear side of the vehicle is not limited to the example 21 shown in FIG. .

In the example shown in FIG. 13, the power transmitted from the transmission is first changed in direction by the direction changing gear 42 so that it is transmitted in the front and back direction, and then distributed to the front wheels and the rear wheels via the center differential 41. It is now possible to do so. That is, a center differential 41 whose axis is oriented toward the front and rear of the vehicle is disposed at the rear lower part of the engine 2, and a shaft 43 having a gear 44 on one end that meshes with the output gear of the transmission is disposed. The center differential 41 is connected to the end via a direction conversion gear 42. A bevel gear 46a. 46
While the front differential 9 is connected through the center differential 41, the propeller shaft 17 is connected to a rear wheel output shaft 47 that projects rearward from the center differential 41.

As the center differential 41, a bevel gear type similar to the center differential 11 shown in FIG. 4 may be used.
The center differential 41 shown in the figure includes a ring gear 41a, double pinion gears 41c and 41d held by a carrier 4lb, and a sun gear 41e, and the power transmitted to the ring gear 41a is transmitted to the carrier 4lb.
It is a double pinion type that is distributed between the LB side and the sangya 41e side.

A front wheel output shaft 45 is connected to the carrier 4lb, and a rear wheel output shaft 47 is connected to the sangya 41e. Further, the direction changing gear 42 is constituted by corresponding bevel gears 42a and 42b provided on the outer periphery of the ring gear 41a of the center differential 41 and the end of the shaft 43.

In the case of such a structure, the drive system is arranged such that the direction conversion gear 42, the center differential 41, and the front differential 9 are all located approximately at the center in the vehicle width direction, but in this case as well,
For example, in accordance with the first embodiment or the second embodiment, the steering shaft 21 and the front exhaust pipe 22 are arranged on both sides of the direction conversion gear 42 (and the center differential 41 and the front differential 9). The steering shaft 21 and the front exhaust pipe 22 can be laid out in accordance with each of the embodiments described above.

[Effects of the Invention] As described above, according to the inventions recited in claims 1 and 2, the engine and the transmission are disposed horizontally at the front of the vehicle, and the front wheel differential and the propeller shaft direction are arranged horizontally. A drive system having a direction conversion gear for transmitting power to the engine is arranged such that the front wheel differential is located on the front side of the vehicle with respect to the engine, and the direction conversion gear is located on the rear side of the vehicle. When arranging the steering shaft and exhaust pipe to pass below the area where the engine and transmission are located in a four-wheel drive vehicle equipped with The propeller shaft connected to the conversion gear, the steering shaft, and the exhaust pipe can be effectively laid out close to each other and closer to the center in the vehicle width direction.

That is, according to the invention described in claim 1, the steering shaft and the exhaust pipe are arranged so as to pass on both sides of the direction changing gear, so that the steering shaft and the exhaust pipe are By positioning the direction changing gear and the propeller shaft near both sides thereof, these can be effectively laid out closer to the center in the vehicle width direction.

According to the invention as set forth in claim 2, the steering shaft and the exhaust pipe are arranged side by side at a position passing through the side opposite to the side where the transmission is located with respect to the direction conversion gear. Even if there is little space below the part where the transmission is located, the steering shaft and exhaust pipe can be located on one side near the direction change gear and propeller shaft, and these can be moved in the vehicle width direction. It can be effectively laid out closer to the center.

Furthermore, according to each of the above-mentioned inventions, a layout that is advantageous in terms of securing ground clearance and the like can be obtained compared to a case where the steering shaft and exhaust pipe are located below a direction changing gear or the like.

25

[Brief explanation of drawings]

1 to 3 are a plan view, a partially sectional front view, and a side view of the main parts, showing a first embodiment of the present invention, and FIG. 4 is a sectional view showing an example of the specific structure of the drive system. 5 and 6 are a plan view and a partial cross-sectional front view of the main parts of the second embodiment, and FIGS. 7 to 9 are a plan view and a front view of the main parts of the third embodiment. 10 to 12 are a plan view and a partially sectional front view and side view of the main parts of the fourth embodiment of the present invention, and FIG. 13 is a drive FIG. 3 is a cross-sectional view showing another example of the specific structure of the system. 2... Engine, 6... Transmission, 7... Axle, 9
...Front differential (differential device for front wheels), 11.41・
... Center differential, 12.42 ... Direction conversion gear, 20
... Steering mechanism, 21... Steering shaft, 22... Exhaust pipe.

Claims (1)

[Claims] 1. An engine and a transmission are mounted horizontally at the front of the vehicle, and a front wheel differential device to which the front wheel axle is connected and a direction conversion gear that transmits power in the direction of the propeller shaft are provided. In a four-wheel drive vehicle in which the front wheel differential is located in front of the engine and the direction conversion gear is located in the rear of the vehicle, the steering mechanism is located closer to the axle. is arranged at the front side of the vehicle, and includes a steering shaft connected to the steering mechanism and extending in the longitudinal direction of the vehicle, and an engine exhaust pipe extending from the front of the axle to the lower side of the axle to the rear side of the vehicle, A horizontal engine type four-wheel drive vehicle, characterized in that the steering shaft and the exhaust pipe are disposed so as to pass on both sides of the direction conversion gear. 2. The engine and transmission are mounted horizontally at the front of the vehicle, and a front wheel differential device to which the front wheel axle is connected and a direction conversion gear that transmits power in the direction of the propeller shaft are mounted on the vehicle relative to the engine. In a four-wheel drive vehicle in which the front wheel differential is located at the front and the direction conversion gear is located at the rear of the vehicle, the steering mechanism is located at the front of the vehicle relative to the axle. and a steering shaft connected to the steering mechanism and extending in the longitudinal direction of the vehicle, and an engine exhaust pipe extending from the front of the axle to the rear of the vehicle through the lower side of the axle, and the steering shaft and the exhaust A transverse engine type four-wheel drive vehicle, characterized in that the pipes are arranged side by side at a position passing on the side opposite to the side where the transmission is located with respect to the direction conversion gear.