JP4910545B2 - Driving force transmission device - Google Patents

Description

In the present invention, one of the front and rear wheels (main drive wheel) is driven by a main power source such as an engine, and the other (sub drive wheel) is driven by an electric motor as a sub power source. About a driving force transmission device useful for use in a motor drive system, etc.
In particular, the present invention relates to a driving force transmission device in which a backlash torque in a direction that eliminates a gap in the driving system is applied in advance to prevent abnormal noise prior to the start of transmission of the driving force transmission device.

  Conventionally, as an electric motor type four-wheel drive vehicle, a vehicle as described in Patent Document 1 is known. The main drive wheel is driven by a main power source such as an engine, and the sub motor is driven by an electric motor as a sub power source. Drive the drive wheels.

In Patent Document 1, a driving force transmission device is further provided in the transmission system between the electric motor and the auxiliary driving wheel,
During forward four-wheel drive running with the electric motor driven forward, the forward drive force of the electric motor is transmitted to the sub drive wheels by fastening the clutch, and the four-wheel drive forward combined with the main drive wheels driven by the engine Enabling travel,
When traveling in forward two-wheel drive with the electric motor stopped, the motor transmission system is shut off by releasing the clutch so that the forward rotation of the auxiliary drive wheel is not transmitted to the electric motor,
When driving in reverse four-wheel drive with the electric motor driven in reverse, the reverse drive force of the electric motor is transmitted to the auxiliary drive wheel by engaging the clutch, and the four-wheel drive combined with the main drive wheel driven by the engine is used. Techniques that enable reverse travel are shown.

By the way, when the forward drive force of the electric motor starts to be transmitted to the sub drive wheel by engaging the clutch from the non-transmission state, or the reverse drive force of the electric motor is transmitted to the sub drive wheel by engaging the clutch from the non-transmission state. When starting, since the transmission starts suddenly after the gap (backlash) in the transmission system due to backlash between the gears disappears, abnormal noise is generated at the start of transmission.
In order to solve this problem, Patent Document 1 further discloses that when the forward drive force of the electric motor is transmitted to the sub drive wheels, the drive load corresponding to the backlash torque is applied to the electric motor so as to eliminate the gap (backlash) of the transmission system in advance. Or
When transmitting the reverse driving force of the electric motor to the auxiliary driving wheel, a technique is shown in which a driving load corresponding to the backlash torque is applied to the electric motor so as to eliminate a gap (backlash) in the transmission system in advance.
JP 2004-098718 A

  However, since the driving force transmission device is composed of the same transmission system including the above-described clutch in which the forward drive system and the reverse drive system are common, the backlash torque when moving forward and the backlash torque when moving backward And the same thing.

  However, in the driving force transmission device that transmits the driving force through a different path between the forward driving system and the backward driving system of the driving force transmission device, the backlash driving torque and the backlash driving system backlash torque If they are the same, there is a problem that abnormal noise is generated at the start of transmission of the drive system during forward movement or backward movement.

  The present invention eliminates the above-mentioned problem in a driving force transmission device in which the bidirectional driving system transmits driving force through different paths so that no abnormal noise is generated at the start of transmission in both of these driving systems. The purpose is to do.

For this purpose, the driving force transmission device according to the invention is constructed as described in claim 1.
First, to explain the driving force transmission device as a premise,
As a transmission system between the input shaft and output shaft,
A positive direction drive system including a positive direction one-way clutch engaged so as to transmit a positive direction driving force to the output shaft at the time of positive direction driving of the input shaft;
The reverse direction one-way clutch that is engaged when the input shaft is driven in the reverse direction, and the reverse direction drive force that is transmitted via the reverse direction one-way clutch are fastened to transmit the reverse direction drive force to the output shaft. Including a reverse drive system including a reverse rotation transmission clutch,
At the start of transmission of the positive direction drive force by the positive direction drive system, a backlash torque in a direction that eliminates the gap in the positive direction drive system is added to the input shaft in advance.
At the start of transmission of the reverse drive force by the reverse drive system, a backlash torque in a direction that eliminates the gap in the reverse drive system is applied in advance to the input shaft.

And this invention, in this driving force transmission device,
The backlash driving torque for the forward direction driving system and the backlashing torque for the reverse direction driving system are different from each other.

Since the driving force transmission device according to the present invention has different backlash torque for the forward direction drive system and backlash torque for the reverse direction drive system,
Even in a driving force transmission device in which the backlash in the bi-directional drive system is different, both of the backlash of these drive systems can be eliminated, and when the backlash torque is determined in accordance with the smaller backlash, the drive system with the larger backlash When noise is generated at the start of transmission due to insufficient backlash torque, or when the backlash torque is determined according to the larger backlash, the drive system with the smaller backlash generates a shock due to excessive backlash torque. Can be resolved.

  Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 schematically shows a drive system of an electric motor type four-wheel drive vehicle including a driving force transmission device 28 according to an embodiment of the present invention.
The drive system of this electric motor type four-wheel drive vehicle uses a drive shaft 43 to drive drive power from a main power source 41 such as an engine through a transaxle 42 and a drive shaft 43 that are a combination of a transmission and a differential gear device. The front engine / front wheel drive car (FF car) that transmits to the left and right front wheels 44 is the base car.
The driving force from the auxiliary power source 45 such as an electric motor is transmitted to the left and right rear wheels 48 that are auxiliary driving wheels via the driving force transmission device 28, the reduction gear 46 including the differential gear device, and the drive shaft 47. It is what I did.
In this embodiment, the driving force transmission device 28 is included in the speed reducer 46 and configured as the same unit.

The driving force transmission device 28 used for the application illustrated in FIG. 1 is specifically configured as shown in FIGS. 2 and 3, for example.
This driving force transmission device includes an input shaft 1 coupled to an electric motor 45, an output shaft 2 offset therefrom, and a differential gear device 3 coupled to a sub driving wheel 48. These input shaft 1 and output The shaft 2 and the differential gear device 3 are arranged in parallel so as to be offset from each other, and are housed in the casing 4.
The casing 4 is configured by combining the casing portions 4a and 4b, and these are coupled to each other by a bolt 5.

The input shaft 1 is rotatably supported on the casing parts 4a and 4b by bearings 1a and 1b, and the end of the input shaft 1 exposed to the outside from the casing part 4b for coupling the electric motor, and the casing part 4b The space between the two is sealed with an oil seal 1c.
The output shaft 2 is rotatably supported on the casing parts 4a and 4b by bearings 2a and 2b at both ends, and stored in the casing 4.
In the differential gear device 3, both ends of the differential gear case 3c are rotatably supported by the casing portions 4a and 4b by bearings 3a and 3b, and are accommodated in the casing 4.
A drive shaft 47 shown in FIG. 1 is coupled to the left and right side gears 3 d of the differential gear device 3, and the left and right side gears 3 d of the differential gear device 3 are coupled to the auxiliary drive wheels 48 via these drive shafts 47.

A forward one-way clutch (forward one-way clutch) 6 and a reverse one-way clutch (reverse one-way clutch) 7 are fitted and provided on the outer periphery of the output shaft 2.
The forward one-way clutch (forward one-way clutch) 6 is composed of an inner ring 6a, an outer ring 6b, and a sprag 6c interposed between these inner and outer rings.
The reverse one-way clutch (reverse one-way clutch) 7 also includes an inner ring 7a, an outer ring 7b, and a sprag 7c interposed between the inner and outer rings.

Thus, the inner ring 6a of the forward one-way clutch 6 is integrally formed with the output shaft 2, and the inner ring 7a of the backward one-way clutch 7 is rotatably fitted on the output shaft 2.
Further, the outer ring 6b of the forward one-way clutch 6 and the outer ring 7b of the backward one-way clutch 7 are integrally formed, and the inner circumferences of both ends thereof are rotatably supported by the bearings 8 and 9 on the output shaft 2 and the inner ring 7a.
An intermediate gear 10 is integrally formed on the outer periphery of the outer ring 6b of the integrally formed forward one-way clutch 6 and the outer ring 7b of the reverse one-way clutch 7. An input gear 11 that meshes with the intermediate gear 10 is integrally formed on the input shaft 1. Provided,
The rotation from the electric motor 45 is input from the input shaft 1 through the gears 11 and 10 to the outer rings 6b and 7b.

The forward one-way clutch 6 is locked when the driving force input from the input shaft 1 through the gears 11 and 10 to the outer rings 6b and 7b is in the forward direction (forward direction). (Positive direction) The driving force is transmitted to the inner ring 6a (output shaft 2).
The reverse one-way clutch 7 is locked when the driving force input from the input shaft 1 through the gears 11 and 10 to the outer rings 6b and 7b is in the reverse direction (reverse direction). It is assumed that the driving force is transmitted to the inner ring 7a.

  An inner ring 7a of the reverse one-way clutch 7 extends an end portion 7d far from the forward one-way clutch 6 in a direction away from the forward one-way clutch 6. Between the inner ring extended end portion 7d and the output shaft 2, the reverse rotation transmission clutch 12 and a cam mechanism 13 for fastening the clutch 12 are interposed.

First, the cam mechanism 13 will be described below.
A one-way clutch-side cam disk 13a that is spline-fitted to the inner ring 7a (specifically, an extended end 7d thereof) of the reverse one-way clutch 7;
The one-way clutch-side cam disk 13a is coaxially opposed to the reverse-rotation transmission clutch-side cam disk 13b disposed so as to be relatively rotatable,
A disc spring type return spring 13c that is contracted between the reverse rotation transmission clutch side cam disk 13b and the housing portion 4a so as to urge the reverse rotation transmission clutch side cam disk 13b in the axial direction toward the one-way clutch side cam disk 13a. When,
When the backward driving force is transmitted to the one-way clutch-side cam disk 13a between the opposing cam grooves of the cam disks 13a, 13b, the one-way clutch-side cam disk 13a is opposed to the return-rotation transmission clutch-side cam disk 13b against the return spring 13c. The thrust cam mechanism includes a cam follower 13d that is displaced in a direction away from the cam follower 13d.

The return spring 13c is seated on the inner periphery of the reverse rotation transmission clutch side cam disk 13b and the outer periphery is seated on the housing part 4a.
4 (a), (b), between the inner periphery of the return spring 13c and the reverse rotation transmission clutch side cam disk 13b at the seating location of the inner periphery of the return spring 13c and the reverse rotation transmission clutch side cam disk 13b. Alternatively, a concave / convex fitting portion for rotation engagement as shown in FIGS. 5 (a) and 5 (b) is set so that the return spring 13c can rotate together with the reverse rotation transmission clutch side cam disk 13b,
By interposing the wear-resistant ring 13e at the seating location between the outer periphery of the return spring 13c and the housing part 4a, the outer periphery of the return spring 13c is prevented from sliding directly on the housing part 4a and wearing it.

As a result, the return spring 13c is slidably brought into contact with other parts not on the inner periphery with a small friction torque but on the outer periphery with a large friction torque, so that the preload of the return spring 13c can be lowered accordingly, and the cam mechanism 13 Since the input torque to be operated can be lowered, the responsiveness of the cam mechanism can be improved.
Although the thrust load on the cam mechanism 13 due to the preload reaches the inner ring 7a of the reverse one-way clutch 7, the inner ring 7a is abutted against the output shaft 12 fixed in the axial direction via the thrust bearing 14. The inner ring 7a is not displaced in the axial direction even by the preload.

The inner periphery of the reverse rotation transmission clutch side cam disk 13b is spline-fitted to the outer periphery of the clutch hub 12a that is rotatably fitted to the inner ring 7a (specifically, the extended end portion 7d) of the reverse one-way clutch 7. The hub 12a is prevented from coming off by a snap ring 12b engaged with an inner ring 7a (specifically, an extended end portion 7d) of the reverse one-way clutch 7.
The clutch hub 12a constitutes a part of the reverse rotation transmission clutch 12 as described below.

The reverse rotation transmission clutch 12 is a wet multi-plate clutch having the following configuration.
That is, the clutch drum 12c is provided on the side of the cam mechanism 13 far from the reverse one-way clutch 7, and the inner periphery of the clutch drum 12c is serrated on the output shaft 2 and screwed to the output shaft 2. It is fixed in the axial direction by a loading nut 12d.
The cam disk 13b is also used as a pressure plate for the reverse rotation transmission clutch 12 (wet multi-plate clutch 12). Therefore, an inner plate 12e and an outer plate 12f are interposed between the axially opposed surfaces of the clutch drum 12c and the cam disk 13b. .

The inner plate 12e is spline-fitted to the outer periphery of the clutch hub 12a that can rotate on the inner ring extension end portion 7d of the reverse one-way clutch 7, so that the inner plate 12e can rotate integrally with the cam disk 13b and the clutch hub 12a. Relative displacement is possible in the axial direction.
The outer plate 12f can be rotated together with the clutch drum 12c by being spline fitted to the inner periphery of the clutch drum 12c so as to be relatively displaceable in the axial direction.

  An output gear 15 is formed integrally with the output shaft 2 between the forward one-way clutch 6 and the bearing 2b, and a ring gear 16 that meshes with the output gear 15 is attached to the differential gear case 3c. From the output gear 15 and the ring gear 16, The final drive gear set and the differential gear device 3 constitute the speed reducer 46 in FIG.

2 and 3, the forward one-way clutch 6 and the reverse one-way clutch 7 are arranged in parallel between the input shaft 1 and the output shaft 2, and the latter reverse one-way clutch 7 is connected to the cam mechanism 13. The input / output shafts 1 and 2 are coupled via the reverse rotation transmission clutch 12 that is fastened by
The driving force transmission device of this embodiment functions as follows when used in an electric motor type four-wheel drive vehicle as shown in FIG.

FIG. 6 (a) is a cross-sectional view for explaining the driving force transmission path of the driving force transmission device 28 with hatching when the electric motor type four-wheel drive vehicle travels forward four-wheel drive.
Here, the rotational direction of the input shaft 1 during forward four-wheel drive will be described as a clockwise direction when viewed from the right side (the electric motor 45 side) of FIG.
6 (b) is a cross-sectional view showing the forward one-way clutch 6 as viewed from the right side (electric motor side) of FIG. 6 (a), and FIG. 6 (c) shows the backward one-way clutch 7 in FIG. It is a cross-sectional view seen from the right side (electric motor side) of a).

During forward four-wheel drive traveling, the forward driving force by the electric motor 45 is transmitted from the input shaft 1 through the input gear 11 and the intermediate gear 10 to the outer wheels 6b and 7b of the one-way clutches 6 and 7, and these outer wheels 6b and 7b. Is rotated in the corresponding forward direction, the outer ring 6b of the forward one-way clutch 6 rotates in the engagement direction with respect to the inner ring 6a, so that the sprag 6c is inclined in the engagement direction as shown in FIG. By engaging the forward one-way clutch 6 (indicated as Lock in the figure), the inner ring 6a is rotated in the forward direction integrally with the outer ring 6b via the sprag 6c.
Therefore, the forward drive force from the electric motor 45 to the outer wheels 6b, 7b is transmitted to the output shaft 2 via the forward one-way clutch 6, and the auxiliary drive wheel 48 can be motor-driven in the forward direction via the differential gear device 3. In combination with the forward drive of the main drive wheels 44 by the engine 41, the vehicle can be driven to drive forward four wheels.

The forward rotation from the electric motor 45 to the outer rings 6b and 7b is also directed to the reverse one-way clutch 7. However, since the rotation direction of the outer ring 7b is the non-engagement direction with respect to the inner ring 7a, the sprag 7c is shown in FIG. ), The outer ring 7b only rotates idly with respect to the inner ring 7a and the forward rotation is transmitted to the inner ring 7a by the non-engagement of the reverse one-way clutch 7 (indicated as Free in the figure). There is nothing.
Due to the non-engagement of the reverse one-way clutch 7, forward rotation from the electric motor 45 to the outer ring 7b is not transmitted to the inner ring 7a, and hence the cam disk 13a of the cam mechanism 13, and relative rotation between the cam disks 13a and 13b does not occur. Therefore, the cam mechanism 13 does not operate and maintains the state shown in FIG. 6 (a), and therefore friction does not occur between the return spring 13c and the wear-resistant ring 13e.

FIG. 7 (a) is an explanatory cross-sectional view showing hatching in the driving force transmission path of the driving force transmission device 28 when the electric motor type four-wheel drive vehicle travels forward two-wheel drive.
In this case as well, the rotational direction of the output shaft 2 during forward two-wheel drive will be described as a clockwise direction when viewed from the right side (electric motor side) in FIG.
FIG. 7 (b) is a cross-sectional view showing the forward one-way clutch 6 as viewed from the right side (electric motor side) of FIG. 7 (a), and FIG. 7 (c) shows the reverse one-way clutch 7 in FIG. It is a cross-sectional view seen from the right side (electric motor side) of a).

During forward two-wheel drive, the electric motor 45 is stopped and the secondary drive wheels 48 are not driven, and the vehicle is driven only by driving the main drive wheels 44 by the engine 41. The motor rotation is not transmitted to 6b and 7b, and the outer rings 6b and 7b remain stopped.
However, since the vehicle is driven by the two-wheel drive of the main drive wheels 44 by the engine 41, the rotation of the sub drive wheels 48 is transmitted from the differential gear device 3 to the output shaft 2 via the gear sets 15 and 16 and output shaft 2 Is reversely driven in the forward rotation direction by the auxiliary drive wheel 48.

The forward rotation by the reverse drive of the output shaft 2 reaches the inner ring 6a of the forward one-way clutch 3 as shown in FIG.
However, since the forward rotation of the inner ring 6a is in the non-engagement direction with respect to the outer ring 6b, the sprag 6c is inclined in the non-engagement direction as shown in FIG. 7 (b), and the forward one-way clutch 6 is disengaged (see FIG. In this case, the inner ring 6a only idles with respect to the outer ring 6b, and the forward rotation from the output shaft 2 is not transmitted to the outer ring 6b.

Due to such disengagement of the forward one-way clutch 6, the forward rotation of the output shaft 2 is not transmitted to the outer ring 6b, and thus the input shaft 1, and power loss due to drag of the electric motor 45 and early wear of the electric motor 45 can be avoided. it can.
Further, since the forward rotation of the output shaft 2 is not transmitted to the cam disk 13a of the cam mechanism 13 and the relative rotation between the cam disks 13a and 13b does not occur, the cam mechanism 13 does not operate and the state of FIG. The cam disk 13b is not rotated together with the release of the reverse rotation transmission clutch 12 by this, and no friction is generated between the cam disk 13b and the wear-resistant ring 13e.

FIG. 8 (a) is a cross-sectional view for explaining the driving force transmission path of the driving force transmission device 28 with hatching when the electric motor type four-wheel drive vehicle travels in reverse four-wheel drive.
Here, the rotation direction of the input shaft 1 during the reverse four-wheel drive will be described as a counterclockwise direction when viewed from the right side (the electric motor 45 side) in FIG.
FIG. 8 (b) is a cross-sectional view showing the forward one-way clutch 6 as viewed from the right side (electric motor side) of FIG. 8 (a), and FIG. 8 (c) shows the reverse one-way clutch 7 in FIG. It is a cross-sectional view seen from the right side (electric motor side) of a).

The reverse driving force by the electric motor 45 is transmitted from the input shaft 1 through the input gear 11 and the intermediate gear 10 to the outer rings 6b and 7b of the one-way clutches 6 and 7, and these outer rings 6b and 7b are rotated in the corresponding reverse direction. When,
Since the outer ring 6b of the forward one-way clutch 6 rotates in the non-engagement direction with respect to the inner ring 6a, the sprag 6c tilts in the non-engagement direction as shown in FIG. In the figure, it is indicated as Free), but the rotation in the reverse direction is not transmitted from the outer ring 6b to the inner ring 6a.
Since the outer ring 7b of the reverse one-way clutch 7 rotates in the engagement direction with respect to the inner ring 7a, the sprag 7c is inclined in the engagement direction as shown in FIG. 8 (c), and the reverse one-way clutch 7 is engaged (Lock in the figure). The inner ring 7a rotates in the backward direction integrally with the outer ring 7b via the sprag 7c.

Therefore, the reverse driving force from the electric motor 45 to the outer rings 6b and 7b is transmitted to the one-way clutch side cam disk 13a of the cam mechanism 13 via the reverse one-way clutch 7.
At this time, the one-way clutch-side cam disk 13a is opposed to the return spring 13c as shown in FIG. 8 (a) by the relative rotation with the reverse rotation transmission clutch-side cam disk 13b via the cam follower 13d. Displace in the axial direction away from 13a.

When the cam mechanism 13 is operated, the reverse rotation transmission clutch side cam disk 13b is in the engaged state by sandwiching the inner plate 12e and the outer plate 12f with the clutch drum 12c due to the above axial displacement. Thus, the reverse drive force that reaches the inner ring 7a from the outer ring 7b via the reverse one-way clutch 7 can be transmitted to the output shaft 2 through the cam mechanism 13 and the reverse rotation transmission clutch 12 in sequence.
Therefore, the reverse drive force from the electric motor 45 to the outer rings 6b, 7b is transmitted to the output shaft 2 via the reverse one-way clutch 7, the cam mechanism 13, and the reverse rotation transmission clutch 12, and is sub-driven via the differential gear device 3. The wheels 48 can be driven by a motor in the reverse direction, and in combination with the reverse drive of the main drive wheels 44 by the engine 41, the vehicle can be driven in reverse four-wheel drive.

During this time, the inner ring 6a of the forward one-way clutch 6 is also rotated in the backward direction together with the output shaft 2. However, immediately after the motor is driven, the rotation speed of the outer ring 6b is faster than the rotation speed of the inner ring 6a (the rotation direction is the same). Is inclined in the non-engagement direction as shown in FIG. 8 (b), the forward one-way clutch 6 is kept in the non-engagement state (indicated as Free in the figure), and the outer ring 6b is engaged after the reverse rotation transmission clutch 12 is engaged. Since the rotation speed of the inner ring 6a becomes equal, the forward one-way clutch 6 does not transmit power between the inner ring 6a and the outer ring 6b.
However, since the output shaft 2 and the inner ring 6a perform the same rotation, the inner and outer rings 6a and 6b of the forward one-way clutch 6 rotate integrally as indicated by arrows in FIG. , 6b between the sprags 6c and the balls in the bearing 8 are rotating in the same manner as shown by hatching in FIG. 8 (a).

Also, when the reverse drive force from the electric motor 45 to the outer wheels 6b, 7b is directed to the output shaft 2 (during reverse four-wheel drive), this reverse drive force passes through the cam disk 13b of the cam mechanism 13 as described above. The outer periphery of the return spring 13c that rotates together with the cam disk 13b rotates relative to the wear-resistant ring 13e fitted to the casing portion 4a, and causes friction between the two.
When the reverse driving force from the electric motor 45 to the outer wheels 6b and 7b is directed to the output shaft 2 (reverse four-wheel drive), since the vehicle is traveling backward, the occurrence frequency and generation time are very small. Friction between the outer periphery of 13c and the casing portion 4a (abrasion-resistant ring 13e) does not reduce the reliability due to wear to a problem and does not increase the transmission loss due to friction to a problem.

And in the driving force transmission device having the above-described configuration,
When realizing forward four-wheel drive travel, forward two-wheel drive travel, and reverse four-wheel drive travel of an electric motor type four-wheel drive vehicle, as is apparent from the above-described operation description, the three travel modes are realized by the automatic operation of the internal mechanism. Therefore, a complicated control mechanism and control system are not required, and this is very advantageous in terms of cost and maintenance.

When the cam mechanism 13 engages the reverse rotation transmission clutch 12 during transmission of the reverse drive force in FIG. 8, the cam disk 13b is shown while the cam disk 13a receives the reaction force in the right direction in the figure on the output shaft 2. The cam plate 13b is used to displace the inner plate 12e and the outer plate 12f against the clutch drum 12c fixed to the output shaft 2 to the left in the figure to engage the reverse rotation transmission clutch 12. At this time, since the thrust force for engaging the clutch acting between the cam disk 13a and the clutch drum 12c is eliminated as an internal force on the output shaft 2, this thrust load must be received by the bearings 2a, 2b and the casing 4. In addition, it is not necessary to make them strong enough to withstand the thrust load, which is advantageous in terms of cost and durability.
That is, since the clutch drum 12c is fixed to the output shaft 2 in the axial direction by the loading nut 12d, the thrust load of the cam disk 13a can be eliminated as an internal force.

Here, the cam mechanism 13 that controls the engagement / release of the reverse rotation transmission clutch 12 will be described in more detail with reference to FIG.
As described above, the cam mechanism 13 includes the cam disks 13a and 13b and the cam follower 13d interposed therebetween. The cam action described above is performed on the mutually opposing surfaces in the axial direction of the cam disks 13a and 13b. Cam grooves are provided in order to obtain them, and FIG. 9 shows these cam grooves as viewed from the outer peripheral side of the cam mechanism 13.

The driving force (torque) input to the cam mechanism 13 is T, the cam radius from the center of the output shaft 2 to the center of the cam follower 13d is Lc, and the cam angle of the cam groove on the opposing surface of the cam disks 13a and 13b (cam mechanism) Is the angle between the axis perpendicular to the axis 13 and the cam groove), the biasing force of the return spring 13c is Fs, the outer diameter of the return spring 13c is Ls, and the coefficient of static friction between the return spring 13c and the housing side wear-resistant ring 13e. Is μ,
In order to operate the cam mechanism 13 when the return spring 13c and the wear-resistant ring 13e are in a static friction state, the following two conditions must be satisfied.

First, in order to satisfy the above requirement, it is necessary that the propulsive force (thrust load) of the cam mechanism 13 be larger than the urging force Fs of the return spring 13c, so that T / (Lc × tanθ)> Fs. Required.
Furthermore, since the frictional force at the contact portion between the return spring 13c and the wear-resistant ring 13e needs to be larger than the cam rotational force obtained by dividing the driving force T acting on the cam mechanism 13 by the Lc, μ × Fs × ( It is also essential that Ls / Lc)> T / Lc.
From these two formulas, a relational expression of Fs × Lc × tanθ <T <μ × Fs × Ls is derived. When the return spring 13c and the wear-resistant ring 13e are in a static friction state, the drive satisfying this formula When the force T is input to the cam mechanism 13 (cam disk 13a), the cam mechanism 13 is operated.

  In order for the cam mechanism 13 to operate while the cam disk 13b (return spring 13c) rotates relative to the wear-resistant ring 13e, the dynamic friction coefficient between the return spring 13c and the wear-resistant ring 13e is μ ′. If so, the following conditions must be satisfied.

First, in order to satisfy the above requirement, it is necessary that the propulsive force (thrust load) of the cam mechanism 13 be larger than the urging force Fs of the return spring 13c, so that T / (Lc × tanθ)> Fs. Required.
Furthermore, since the rotational force of the cam mechanism 13 does not exceed the frictional force between the return spring 13c and the wear-resistant ring 13e, it is essential that μ ′ × Fs × (Ls / Lc) = T / Lc. It becomes.
From these two formulas, a relational expression of μ ′> (Lc / Ls) tanθ is derived, and when the wear-resistant ring 13e and the return spring 13c are in a dynamic friction state, the relationship between the wear-resistant ring 13e and the return spring 13c is obtained. Is greater than μ ′ satisfying this expression, the cam mechanism 13 is operated.

The reverse rotation transmission clutch 12 is self-locked and self-locked by the operation of the cam mechanism 13 when a driving force that allows the cam disk 13a to rotate relative to the cam disk 13b is input to the cam mechanism 13. The
Further, if the driving force is not input to the cam mechanism 6 in the self-locked state, the torque for rotating the cam disk 13a relative to the cam disk 13b as described above is also eliminated, so that the cam disk that receives the spring force of the return spring 13c. While the cam follower 13dc rolls to the original position in the cam groove, the cam disk 13a rotates to the original relative rotational position with respect to the cam disk 13b.
As the cam disk 13a rotates, the cam disk 13b is displaced so as to approach the cam disk 13a, and the reverse rotation transmission clutch 12 can be released by releasing the self-lock.

By the way, in the above embodiment, the reverse rotation transmission clutch 12 is constituted by a wet multi-plate clutch.
As the reverse rotation transmission clutch 12, an arbitrary type such as a dog clutch as shown in FIG. 10 or a friction clutch as shown in FIG. 11 can be used.

When the reverse rotation transmission clutch 12 is configured as a dog clutch as shown in FIG. 10, an annular clutch gear 17 is integrally formed or integrally connected to the surface of the cam disk 13b far from the cam disk 13a, and is coaxially opposed to this. An annular clutch gear 18 is provided, and the inner periphery of the annular clutch gear 18 is rotationally engaged with the output shaft 2 so that it cannot be displaced in the axial direction in the same manner as the clutch drum 12c.
Such a dog clutch type reverse rotation transmission clutch 12 is configured such that when the cam disk 13b moves left from the released position in FIG. 10 by the operation of the cam mechanism 13, the annular clutch gear 17 meshes with the annular clutch gear 18, and the clutch is engaged. 45 allows the auxiliary drive wheel 48 to be driven backward.

When the reverse rotation transmission clutch 12 is constituted by a friction clutch as shown in FIG. 11, a clutch friction member 19 is provided on the surface of the cam disk 13b far from the cam disk 13a by integral molding or integrally coupled, and is arranged so as to face it at the same time. Then, the friction clutch member 20 is provided, and the inner periphery of the friction clutch member 20 is rotationally engaged with the output shaft 2 so that it cannot be displaced in the axial direction in the same manner as the clutch drum 12c.
When the friction member 19 moves leftward from the released position in FIG. 11 by the operation of the cam mechanism 13, the friction clutch type reverse rotation transmission clutch 12 enters the clutch engagement state by pressing the friction member 19 against the friction clutch member 20. The sub-drive wheels 48 can be driven backward by the motor 45.

In the above description, the forward one-way clutch 6 and the reverse one-way clutch 7 are of the sprag type. However, the one-way clutches 6 and 7 may be of a roller type as shown in FIG.
The one-way clutches 6 and 7 in FIG. 12 elastically support the roller 6e (7e) between the inner and outer rings 6a (7a) and 6b (7b) to the idling position shown in the figure by a spring 6f (7f), and the inner and outer rings 6a (7a) , 6b (7b), when the roller 6e (7e) rotates relative to the spring 6f (7f) against the spring 6f (7f), the roller 6e (7e) moves between the inner and outer rings 6a (7a), 6b (7b). Is used to transmit power.
Further, the one-way clutches 6 and 7 in FIG. 13 hold the rollers 6e (7e) between the inner and outer rings 6a (7a) and 6b (7b) at predetermined intervals in the circumferential direction by the cage 6g (7g), ), 6b (7b) when the roller 6e (7e) is relatively rotated in the direction in which the inner and outer rings 6a (7a), 6b (7b) are engaged, the roller between the inner and outer rings 6a (7a), 6b (7b) The power is transmitted by engaging through 6e (7e).

FIG. 14 schematically shows a drive system of an electric motor type four-wheel drive vehicle including a driving force transmission device 28 according to another configuration of the present invention.
The drive system of this electric motor type four-wheel drive vehicle uses a driving force from an engine 51 as a main power source, a transmission 52, a propeller shaft 53, a final reduction gear 54 including a differential gear device, and a left and right drive shaft 55. The front engine and rear wheel drive vehicle (FR vehicle), which is transmitted to the left and right rear wheels 56, which are the main drive wheels, is the base vehicle.
The driving force of the electric motor 57 is transmitted to the left and right front wheels 62 which are auxiliary driving wheels via the driving force transmission device 28, the reduction gear 59, the final reduction gear 60 including the differential gear device, and the drive shaft 61. Is.
The driving force transmission device 28 according to an embodiment of the present invention may be disposed between the speed reducer 59 and the final speed reducer 60.

The driving force transmission device 28 used for the application illustrated in FIG. 14 is specifically configured, for example, as clearly shown in FIG. 15, and the same parts in FIG. 15 as in FIGS. 2 and 3 are the same. A reference numeral is attached.
15 includes an input shaft 1 to be coupled to the electric motor 57, an output shaft 2 to be coupled to the sub drive wheel 62 side (to the speed reducer 59 in FIG. 14), and a thrust bearing 31. And are fitted so as to be rotatable relative to each other via a needle bearing 32.
The input shaft 1 is rotatably supported on the casing 4 by a bearing 33, and the output shaft 2 is rotatably supported on the casing 4 by a bearing 34.

A forward one-way clutch 6 and a reverse one-way clutch 7 are provided on the outer periphery of the output shaft 2 sequentially from the input shaft 1 side. These one-way clutches 6 and 7 are the same as those in FIGS. Arranged next to each other and fitted to the outer periphery of the output shaft 2.
The forward one-way clutch 6 is integrally formed with the inner ring 6a so that the inner ring 6a rotates together with the output shaft 2, and the corresponding end portion of the output shaft 2 is enlarged for this integral molding, and the enlarged one-way clutch is moved forward. 6 inner ring 6a.
The reverse one-way clutch 7 is fitted to the inner ring 7a via a needle bearing 35 so that the inner ring 7a can rotate relative to the output shaft 2.
Then, a thrust bearing 14 is interposed between the inner ring 6a of the forward one-way clutch 6 and the inner ring 7a of the reverse one-way clutch 7, so that the inner rings 6a and 7a can be smoothly rotated relative to each other even when they are pressed against each other.

The outer rings 6b and 7b of the forward one-way clutch 6 and the reverse one-way clutch 7 are integrated with each other by integral coupling or integral molding, and coupled to the input shaft 1 by a serration fitting 36, and both one-way clutches are connected via the input shaft 1. The outer rings 6b and 7b of 6 and 7 are coupled to the electric motor 57 in common.
Since the outer rings 6b and 7b of the one-way clutches 6 and 7 are integrated with each other as described above, the outer rings 6b and 7b can be rotatably supported by the pair of bearings 8 and 9 with respect to the inner rings 6a and 7a. The total axial length of the clutches 6 and 7 can be shortened.

  The end 7d of the inner ring 7a of the reverse one-way clutch 7 far from the forward one-way clutch 6 extends in a direction away from the forward one-way clutch 6, and between the inner ring extended end 7d and the output shaft 2, FIGS. A reverse rotation transmission clutch 12 similar to the above and a cam mechanism 13 for fastening the clutch are interposed.

The cam mechanism 13 functions in the same manner as in FIG. 2 and FIG.
A one-way clutch-side cam disk 13a that is spline-fitted to the inner ring 7a (specifically, an extended end 7d thereof) of the reverse one-way clutch 7;
In the axial direction toward the one-way clutch side cam disk 13a, the reverse rotation transmission clutch side cam disk 13b pressed by the preload by the return spring 13c,
Between these cam disks 13a and 13b, when a backward driving force is transmitted to the one-way clutch side cam disk 13a, a cam follower 13d that displaces the backward rotation transmission clutch side cam disk 13b away from the one-way clutch side cam disk 13a. A thrust cam mechanism.

Here, the inner periphery of the reverse rotation transmission clutch side cam disk 13b is spline-fitted to the outer periphery of the clutch hub 12a that is rotatably fitted to the extended end 7d of the inner ring 7a that forms the reverse one-way clutch 7. Is prevented by the snap ring 12b.
The clutch hub 12a and the snap ring 12b constitute a part of the reverse rotation transmission clutch 12.

The return spring 13c is a disc spring similar to that shown in FIGS. 2 and 3, and its inner periphery is engaged with the cam disk 13b and its outer periphery is engaged with the casing 4, so that the return spring 13c is contracted between the cam disk 13b and the casing 4. Then, a preload in the axial direction is applied to the cam disk 13b to press it against the cam disk 13a.
The thrust load due to the preload reaches the inner ring 6a via the spacer ring 37, the bearing 9, the inner ring 7a and the thrust bearing 14, and then reaches the casing 4 via the thrust bearing 31, the input shaft 1, and the bearing 33. The inner ring 7a is not displaced in the axial direction even by this preloading.

The reverse rotation transmission clutch 12 has the following configuration similar to the wet multi-plate clutch described above with reference to FIGS.
That is, the clutch drum 12c is provided on the side of the cam mechanism 13 far from the reverse one-way clutch 7, and the inner periphery of the clutch drum 12c is coupled to the output shaft 2.
The clutch drum 12c is sandwiched between a snap ring 38 engaged on the output shaft 2 and a spacer ring 39 interposed between the clutch drum 12c and the bearing 34, whereby the clutch drum 12c is axially aligned on the output shaft 2. Directional positioning.

The cam disk 13b is also used as a pressure plate for the reverse rotation transmission clutch 12, and therefore, the inner plates 12e and the outer plates 12f are alternately disposed between the opposing surfaces in the axial direction of the clutch drum 12c and the cam disk 13b.
The inner plate 12e is spline-fitted to the outer periphery of the clutch hub 12a that can rotate on the inner ring extension end portion 7d of the reverse one-way clutch 7, so that the inner plate 12e can rotate integrally with the cam disk 13b and the clutch hub 12a. Relative displacement is possible in the axial direction.
The outer plate 12f can be rotated together with the clutch drum 12c by being spline fitted to the inner periphery of the clutch drum 12c so as to be relatively displaceable in the axial direction.

15, the forward one-way clutch 6 and the backward one-way clutch 7 are connected in parallel between the input shaft 1 coupled to the electric motor 57 and the output shaft 2 coupled to the sub drive wheel 62 side. And the latter reverse one-way clutch 7 is coupled between the input and output via a reverse rotation transmission clutch 12 fastened by a cam mechanism 13.
Also, coupled with the forward one-way clutch 6, the reverse one-way clutch 7, the reverse rotation transmission clutch 12, and the cam mechanism 13 for fastening the same as in FIGS. 2 and 3,
When used in an electric motor type four-wheel drive vehicle as shown in FIG. 14, it functions in the same manner as the driving force transmission device described above, and can provide the same effects.

In any of the driving force transmission devices described above, when switching from a non-transmission state to a transmission state that transmits forward drive force or reverse drive force, backlash between gears, gaps in the reverse rotation transmission clutch 12, etc. Since the transmission starts suddenly after the play in the transmission system is eliminated, abnormal noise or vibration is generated at the start of transmission, or the durability of the transmission system is adversely affected.
Therefore, when transmitting the forward drive force of the electric motor to the sub drive wheels, a drive load corresponding to the backlash torque is applied to the electric motor in advance so as to eliminate the gap (backlash) of the transmission system,
When transmitting the reverse drive force of the electric motor to the sub drive wheels, by applying a driving load corresponding to the backlash torque to the electric motor in advance so as to eliminate the gap (backlash) of the transmission system,
It is preferable to prevent abnormal noise or vibration from occurring at the start of transmission or adversely affecting the durability of the transmission system.

In this embodiment, the backlash torque is determined as follows.
First, the case where the driving force transmission unit is as shown in FIGS.
When the reverse drive force is transmitted (reverse four-wheel drive), the condition for closing the clutch clearance of the reverse rotation transmission clutch 12 without rotating the cam disk 13b is that the return spring 13c in the state where the clutch clearance of the reverse rotation transmission clutch 12 is eliminated. If the urging force (spring force) of Fs 'is Fs' and the input torque to the outer rings 6b and 7b of the one-way clutches 6 and 7 is Tc,
Cam radius Lc from the center of the output shaft 2 to the center of the cam follower 13d, cam angle θ of the cam groove on the opposing surface of the cam disks 13a and 13b (see FIG. 9), outer diameter Ls of the return spring 13c, and return This is expressed by the following equation using the coefficient of static friction μ between the outer periphery of the spring 13c and the wear-resistant ring 13e.
Fs '・ Lc ・ tanθ <Tc <μ ・ Fs' ・ Ls

Therefore, the backlash driving torque Tr for eliminating the backlash of the reverse drive system including the clutch clearance of the reverse rotation transmission clutch 12 due to the preliminary rotation of the input shaft 1 is expressed by the number of teeth of the input gear 11 and the number of teeth of the intermediate gear 10. Assuming N2, the shaft torque of the input shaft 1 is converted by the following equation.
Tr = rotation friction of input shaft 1 + friction upstream of reverse rotation transmission clutch 12 on output shaft 2 × (N1 / N2)
+ Backward rotation transmission clutch 12 backlash torque Tc x (N1 / N2)

At this time, in order to accurately predict the backlash drive system backlash torque Tr, it is preferable to determine the backlash torque Tr according to the control program of FIG.
The control program in FIG. 16 is executed while the driving force transmission unit is not transmitting,
First, in step S1, the selection range of the transaxle 42 in FIG. 1 is determined, and it is determined whether the driving force transmission unit shown in FIGS. 2 and 3 performs forward driving or reverse driving at the start of transmission. judge.

When it is determined that the R (reverse running) range is determined in step S2, the oil temperature of the driving force transmission unit is detected in step S3, and in step S4, the oil temperature determined in advance and the friction of the unit transmission system are determined. Based on the map illustrated in FIG. 17 showing the relationship, the friction of each part in the above equation is searched from the oil temperature.
Next, in step S5, the backlash drive system backlash torque Tr is calculated by performing the above equation.
In step S6, the electric motor 45 is energized in the reverse drive force generation direction so as to generate the backlash drive system backlash torque Tr.
In step S7, by holding the urging force of the electric motor 45 until the start operation is performed, backlash of the reverse drive system is continued until the start.

When the drive force transmission unit shown in FIGS. 2 and 3 transmits forward drive force (forward four-wheel drive), the forward drive system backlash torque Td for eliminating the forward drive system backlash is applied to the forward drive system by the clutch 12 and Since the cam mechanism 13 is not included, the backlash drive system backlash torque Td is determined by the following equation in terms of the shaft torque of the input shaft 1 different from the backlash drive system backlash torque Tr.
Td = rotational friction of input shaft 1 + rotational friction of output shaft 2 x (N1 / N2)

At this time, in order to accurately predict the backlash driving torque Td of the forward drive system, it is preferable to determine the backlash torque Td by the control program of FIG.
That is, when it is determined in step S8 that the transaxle 42 in FIG. 1 is selecting the D (forward running) range and the driving force transmission unit shown in FIGS. 2 and 3 performs forward driving at the start of transmission,
In step S9, the oil temperature of the driving force transmission unit is detected, and in the next step S10, the oil temperature is determined based on the map illustrated in FIG. 17 showing the relationship between the oil temperature determined in advance and the friction of the unit transmission system. From the above, the friction of each part in the above equation is searched.
Next, in step S11, the backlash driving torque Td of the forward drive system is calculated by performing the above calculation.
In step S12, the electric motor 45 is energized in the forward drive force generation direction so that the backlash drive torque Td of the forward drive system is generated.
In step S7, the urging of the electric motor 45 is maintained until the start operation is performed, so that the backlash of the forward drive system is continued until the start.

  If it is required to determine the backlash drive torque Tr and the forward drive torque Td more easily, the control program shown in FIG. 18 determines the backlash torque Tr and Td. You can also

In step S1, step S2, and step S8, the same selection range determination as in the step indicated by the same reference numeral in FIG. 16 is performed.
In step S2, when the R (reverse running) range is determined and the driving force transmission unit shown in FIGS. 2 and 3 performs reverse drive at the start of transmission,
In step S13, each part friction at the time of the minimum oil temperature among the operating oil temperatures of the driving force transmission unit is fixedly used, and the backlash drive system backlash torque Tr is obtained by the above-described corresponding calculation formula. Energize the electric motor 45 in the direction of generating the backward drive force so that the stuffing torque Tr is generated,
In step S7, by holding the urging force of the electric motor 45 until the start operation is performed, backlash of the reverse drive system is continued until the start.

In step S8, when the D (forward running) range is determined and the driving force transmission unit shown in FIGS. 2 and 3 performs forward driving at the start of transmission,
In step S14, each part friction at the time of the lowest oil temperature among the operating oil temperatures of the driving force transmission unit is fixedly used, and the backlash driving torque Td of the forward drive system is obtained by the corresponding arithmetic expression described above. Energize the electric motor 45 in the direction of forward drive force generation so that the stuffing torque Td is generated,
In step S7, by holding the urging force of the electric motor 45 until the start operation is performed, backlash of the reverse drive system is continued until the start.

Next, how to determine the backlash drive system backlash torque Tr and the forward drive system backlash torque Td when the driving force transmission unit is as shown in FIG. 15 will be described.
When the reverse drive force is transmitted (reverse four-wheel drive), the condition for closing the clutch clearance of the reverse rotation transmission clutch 12 without rotating the cam disk 13b is that the return spring 13c in the state where the clutch clearance of the reverse rotation transmission clutch 12 is eliminated. Fs' and the input torque from the input shaft 1 to the outer rings 6b and 7b of the one-way clutches 6 and 7 as Tc,
Cam radius Lc from the center of the output shaft 2 to the center of the cam follower 13d, cam angle θ of the cam groove on the opposing surface of the cam disks 13a and 13b (see FIG. 9), outer diameter Ls of the return spring 13c, and return This is expressed by the following equation using the static friction coefficient μ between the outer periphery of the spring 13c and the housing 4.
Fs '・ Lc ・ tanθ <Tc <μ ・ Fs' ・ Ls

Therefore, the backlash torque Tr for eliminating the backlash of the reverse drive system including the clutch clearance of the reverse rotation transmission clutch 12 due to the preliminary rotation of the input shaft 1 is expressed by the following equation in terms of the shaft torque of the input shaft 1. It will be a thing.
Tr = Friction upstream of reverse rotation transmission clutch 12 + Backlash rotation transmission clutch 12 backlash torque Tc

When the driving force transmission unit shown in FIG. 15 transmits forward driving force (forward four-wheel drive), the forward drive system backlash torque Td for eliminating the forward drive system backlash is the clutch 12 and cam mechanism in the forward drive system. Since 13 is not included, the backlash drive system backlash torque Td is determined by the following equation in terms of the shaft torque conversion of the input shaft 1 different from the backlash drive system backlash torque Tr.
Td = rotational friction of input shaft 1 + rotational friction of one-way clutch

In order to predict the backlash driving system backlash torque Tr and the forward driving system backlash torque Td with high accuracy, the control program shown in FIG. Determine Td,
When it is required to more easily determine the backlash drive torque Tr and the forward drive torque Td, the control program shown in FIG. Determine Tr and Td.

According to the driving force transmission device according to the above-described embodiment, the backlash driving system backlash torque Tr and the backlash driving system backlash torque Tr are different from each other.
The driving force transmission devices shown in FIGS. 2 and 3 and the driving force transmission device shown in FIG. Both of them can be eliminated, and the drive system with larger backlash generates abnormal noise or vibration at the start of transmission due to insufficient backlash torque, or the durability of the drive system is reduced due to sudden start of transmission of the drive system. Can be eliminated.

In the above description, as described above with reference to FIGS. 1 and 14, the front engine / front wheel drive (FF vehicle) and the front engine / rear wheel drive (FR vehicle) are the base vehicles.
The drive force transmission device 28 is also applied to vehicles with midship engines and vehicles with rear engines and rear wheel drives (RR vehicles) as the base vehicle, where the wheels not driven by the engine are driven by an electric motor. It goes without saying that it is possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view showing a wheel drive system of an electric motor type four-wheel drive vehicle provided with a drive force transmission device according to an embodiment of the present invention in a transmission system of auxiliary drive wheels. FIG. 2 is an overall longitudinal side view of a driving force transmission device used in the electric motor type four-wheel drive vehicle of FIG. FIG. 3 is an enlarged longitudinal sectional side view of a main part of the driving force transmission device in FIG. The return spring which comprises the cam mechanism in the drive force transmission device is shown, (a) is the front view, (b) is the vertical side view. The other example of this return spring is shown, (a) is the front view, (b) is the vertical side view. FIGS. 2A and 2B are explanatory diagrams showing the transmission path of the driving force transmission device shown in FIGS. 2 and 3 in the case where the electric motor type four-wheel drive vehicle performs forward four-wheel drive traveling, and FIG. FIG. 2 is an overall longitudinal side view similar to FIG. 2, (b) is a partial cross-sectional view showing a state of the forward one-way clutch in the driving force transmission device, and (c) is a backward one-way clutch in the driving force transmission device. It is a partial cross-sectional view which shows the state. FIG. 2 is an explanatory diagram showing a transmission system path of the same driving force transmission apparatus when an electric motor type four-wheel drive vehicle performs forward two-wheel drive traveling, and (a) is a diagram illustrating the transmission system path with FIG. A similar overall longitudinal side view, (b) is a partial cross-sectional view showing the state of the forward one-way clutch in the driving force transmission device, and (c) is a partial cross-section showing the state of the reverse one-way clutch in the driving force transmission device. FIG. FIG. 2 is an explanatory diagram showing a transmission system path of the driving force transmission device when an electric motor type four-wheel drive vehicle performs a reverse four-wheel drive traveling, and (a) is a diagram illustrating the transmission system path with FIG. A similar overall longitudinal side view, (b) is a partial cross-sectional view showing the state of the forward one-way clutch in the driving force transmission device, and (c) is a partial cross-section showing the state of the reverse one-way clutch in the driving force transmission device. FIG. It is a schematic diagram for explaining the operating principle of a cam mechanism for operating a reverse rotation transmission clutch in the driving force transmission device. It is a principal part vertical side view which shows the other structural example of the reverse rotation transmission clutch in a drive force transmission device. It is a principal part vertical side view which shows the further another structural example of the reverse rotation transmission clutch in a drive force transmission device. It is a principal part front view which shows the other example of the forward one-way clutch and reverse one-way clutch in a driving force transmission device. FIG. 10 is a front view of a main part showing still another example of a forward one-way clutch and a backward one-way clutch in a driving force transmission device. FIG. 6 is a schematic plan view showing a wheel drive system of another type of electric motor type four-wheel drive vehicle provided with a drive force transmission device according to the present invention in a transmission system of auxiliary drive wheels. FIG. 15 is an overall longitudinal side view of a driving force transmission device used in the electric motor type four-wheel drive vehicle of FIG. It is a flowchart which shows the control program performed when the driving force transmission device which becomes one Example of this invention performs the backlash | playback drive system backlash and the forward drive system backlash. It is the diagram which showed the relationship between the oil temperature of the driving force transmission unit used in the program, and friction. It is a flowchart which shows the control program performed when the drive force transmission device which becomes another Example of this invention performs the backlash | playback drive system backlash and the forward drive system backlash.

Explanation of symbols

1 Input shaft 2 Output shaft 3 Differential gear device 4 Housing 6 Forward one-way clutch (forward one-way clutch)
7 Reverse one-way clutch (reverse one-way clutch)
8,9 Outer ring bearing
10 Intermediate gear
11 Input gear
12 Reverse rotation transmission clutch (reverse rotation transmission clutch)
13 Cam mechanism
28 Driving force transmission device
41 Main power source
42 Transaxle
43 Drive shaft
44 Left and right front wheels (main drive wheels)
45 Secondary power source
46 Reducer
47 Drive shaft
48 Left and right rear wheels (sub drive wheels)
51 engine
52 Transmission
53 Propeller shaft
54 Final reduction gear
55 Drive shaft
56 Left and right rear wheels (main drive wheels)
57 Electric motor
59 Reducer
60 Final reduction gear
61 Drive shaft
62 Left and right front wheels (sub drive wheels)

Claims (12)

As a transmission system between the input shaft and output shaft,
A positive direction drive system including a positive direction one-way clutch engaged so as to transmit a positive direction driving force to the output shaft at the time of positive direction driving of the input shaft;
The reverse direction one-way clutch that is engaged when the input shaft is driven in the reverse direction, and the reverse direction drive force that is transmitted via the reverse direction one-way clutch are fastened to transmit the reverse direction drive force to the output shaft. Including a reverse drive system including a reverse rotation transmission clutch,
At the start of transmission of the positive direction drive force by the positive direction drive system, a backlash torque in a direction that eliminates the gap in the positive direction drive system is added to the input shaft in advance.
In starting the transmission of the reverse direction driving force by the reverse direction driving system, in the driving force transmitting device in which the backlash torque in the direction to eliminate the gap in the reverse direction driving system is added to the input shaft in advance.
The driving force transmission device characterized in that the backlash driving torque for the forward direction driving system is different from the backlashing torque for the reverse direction driving system. The driving force transmission device according to claim 1,
The driving force transmission device characterized in that the backlash driving torque for the reverse direction driving system is larger than the backlashing torque for the forward direction driving system. In the driving force transmission device according to claim 2,
The driving characterized in that the backlash driving torque for the reverse direction driving system is larger than the backlashing torque for the forward direction driving system by only the torque necessary to eliminate the clearance of the reverse direction rotation transmission clutch. Power transmission device. In the driving force transmission device according to any one of claims 1 to 3,
The driving force transmission device, wherein the backlash driving torque for the forward drive system and the backlash driving torque for the reverse drive system are each changed according to the operating oil temperature. In the driving force transmission device according to any one of claims 1 to 4,
The driving force transmission device is
The forward one-way clutch and the reverse one-way clutch are fitted on the output shaft,
The input shaft is drivingly coupled to the outer ring of these one-way clutches,
The inner ring of the forward one-way clutch can be rotated integrally with the output shaft, and the inner ring of the reverse one-way clutch can be rotated relative to the output shaft.
A driving force transmission device in which the reverse rotation transmission clutch is interposed between an inner ring of the reverse one-way clutch and an output shaft. In the driving force transmission device according to claim 5,
The driving force transmission device is
A driving force transmission device in which outer rings of the forward one-way clutch and the reverse one-way clutch are integrally formed. In the driving force transmission device according to claim 6,
The driving force transmission device is
The input shaft is offset from the output shaft and arranged in parallel;
A driving force transmission device in which the input shaft is rotationally engaged with an outer ring integrated with the forward one-way clutch and the reverse one-way clutch. In the driving force transmission device according to claim 6,
The driving force transmission device is
The input shaft is arranged coaxially with the output shaft,
A driving force transmission device in which the input shaft is rotationally engaged with an outer ring integrated with the forward one-way clutch and the reverse one-way clutch. In the driving force transmission device according to any one of claims 5 to 8,
The reverse rotation transmission clutch interposed between the inner ring of the reverse one-way clutch and the output shaft generates a cam mechanism in response to the reverse drive force transmitted to the inner ring of the reverse one-way clutch. A driving force transmission device that is fastened by a thrust load. In the driving force transmission device according to claim 9,
The cam mechanism is
One-way clutch-side cam disk that rotates with the inner ring of the reverse-direction one-way clutch, a reverse-rotation transmission clutch-side cam disk that is biased toward the cam disk and faces the cam disk so as to be relatively rotatable, and the cam disks When the reverse driving force is transmitted to the one-way clutch-side cam disk, the reverse-rotation transmission clutch-side cam disk is moved to the one-way clutch-side cam disk by relative rotation with the reverse-rotation transmission clutch-side cam disk. A driving force transmission device comprising a cam follower that generates the thrust load by being displaced in the axial direction away from the disk. In the driving force transmission device according to claim 10,
The reverse rotation transmission clutch side cam disk is biased by a disc spring provided between the cam disk and the fixed portion,
A driving force transmission device in which the inner periphery of the disc spring is seated on the reverse rotation transmission clutch side cam disk so as not to rotate relative to the cam disk. In the driving force transmission device according to claim 9-11,
The reverse rotation transmission clutch includes a clutch drum fixed to the output shaft, and is fastened by pressing a clutch plate against the clutch drum with the thrust load.

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