JPH0471930A - Power transmission device for four-wheel drive - Google Patents

Abstract

PURPOSE:To enable proper selection between unidirectional clutches with simple constitution by providing a cam mechanism operating in a different axial direction, according to the rotational direction of a main drive shaft and a driven shaft, and selecting the clutch for forward or backward travel. CONSTITUTION:A pair of unidirectional clutches 3 and 4 is provided between a main drive shaft 1 for transmitting engine output rotation to main drive wheels as front wheels, and a driven gear 2 interlocked and connected to driven wheels. The clutches 3 and 4 are selected with a cam mechanism 5. Each of the unidirectional clutches 3 and 4 is so constituted as to satisfy the predetermined positional relationship between inner rings 30 and 40, and outer rings 31 and 41, and to function only when springs 32 and 34 are kept in contact with the track plane of the rings. Also, the clutches 3 and 4 are laid in a direction opposite to each other, so as to function for the different rotational directions of the main drive shaft 1 at the time of travelling forward and backward. Also, the cam mechanism 5 is constituted with a base plate 50 of disc shape integrated with the intermediate section of the main drive shaft 1, and a pair of presser plates 51 and 52 externally so coupled to the main drive shaft 1 as to be freely slidable.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a unidirectional drive shaft interposed between a main drive shaft that rotates in conjunction with one of front and rear wheels and a slave drive shaft that rotates in conjunction with the other. The present invention relates to a four-wheel drive power transmission device that achieves a four-wheel drive state through the operation of a clutch.

[Conventional technology]

Four-wheel drive vehicles, which transmit the engine's driving force to both the front and rear wheels to improve driving stability, are basically realized by directly connecting the front and rear wheels. However, in this case, when turning on a road surface with a high coefficient of friction, such as a dry paved road, the difference in rotational speed that occurs between the front and rear wheels due to the difference in their respective turning trajectories cannot be absorbed, and tight corner braking However, there is a problem in that a turning phenomenon occurs and smooth cornering is hindered.

A four-wheel drive power transmission device using a one-way clutch has been put into practical use as a device that can overcome these difficulties when the front and rear wheels are directly connected.

This is because the turning trajectory of the front and rear wheels when turning is always with the wheel on the steered side (the front wheel for boat fishing) on the outside, and the difference in rotational speed that causes tight corner braking is caused by the steered wheels. This method focuses on the fact that the rotation occurs in the direction of the preceding rotation.

A one-way clutch is interposed between a main drive shaft that rotates in conjunction with one of the rear wheels and a slave drive shaft that rotates in conjunction with the other so as to perform a coupling operation only when a non-steered wheel rotates in advance. It has become. However, in this case, in order to cope with the fact that the rotation direction of the front and rear wheels is reversed when moving forward and backward,
It is necessary to provide a pair of one-way clutches between the main drive shaft and the slave drive shaft that operate in these different rotational directions, and to switch between them depending on the direction of travel. In the power transmission device disclosed in Japanese Utility Model Application Publication No. 61-81428, this switching is achieved by fitting the inner rings of a pair of one-way wheels onto the main drive shaft (or slave drive shaft), while This is accomplished by disposing a switching sleeve operatively connected to the slave drive shaft (or main drive shaft) on the outside of the outer ring, and moving the sleeve in the longitudinal direction of the shaft to engage one of the outer rings.

[Problems to be Solved by the Invention] However, in the above-mentioned Japanese Utility Model Application Publication No. 61-81428, the switching sleeve is connected to the base end of the shift lever, and the switching sleeve is connected to the base end of the shift lever, and the switching sleeve is moved in response to the operation of the lever toward the forward or reverse side. , or a vacuum actuator is provided to drive the switching sleeve, and the pressure introduced into the actuator is changed in accordance with the operation of the shift lever. The disclosure merely discloses a configuration in which the sleeve is moved in accordance with the operation of a shift lever.

The former configuration requires a link mechanism to connect the switching sleeve to the shift lever, which has the disadvantage of increasing the number of parts and assembly man-hours. There is a disadvantage that the location is limited.

In the latter configuration, the restriction on the installation position is eliminated, but the number of parts and assembly man-hours are actually increased, and the vacuum actuator is bulky, making it difficult to secure the space for its installation. The problem is that it involves

In addition to the above-mentioned Utility Model Application No. 61-81428, various proposals have been made for power transmission devices using one-way clutches, but in all of them, the power transmission device using a one-way clutch is This method utilizes changes in the operating position of a shift lever located at a distance from the transmission device, and has exactly the same drawbacks.

The present invention has been made in view of the above circumstances, and provides reliable switching operation with a simple configuration by switching between a forward one-way clutch and a reverse one-way clutch without operating a shift lever. The purpose of the present invention is to provide a power transmission device that can perform the following functions.

[Means to solve the problem]

The four-wheel drive power transmission device according to the present invention includes a front.

A pair of rear wheels, between a main drive shaft that rotates in conjunction with one of the rear wheels and a slave drive shaft that rotates in conjunction with the other, allowing the wheel on the steered side of the two wheels to rotate forwardly and backwardly, respectively. In a four-wheel drive drive coupling device that includes a one-way clutch and selectively switches the clutch depending on the direction of travel, the four-wheel drive drive coupling device is configured on the main drive shaft or the slave drive shaft, and is configured on the main drive shaft or the slave drive shaft, and switches the one-way clutch depending on the direction of rotation thereof. Operates in different directions along the axial length,
The present invention is characterized in that it includes a cam mechanism that performs switching to each of the one-way clutches.

[Effect]

The present invention utilizes the fact that the rotation directions of the main drive shaft and the slave drive shaft connected to the front and rear wheels are reversed when moving forward and when moving backward, and one of these shafts is rotated according to the direction of rotation. A cam mechanism is configured that operates in different directions in the axial direction, and the operation of the cam mechanism causes switching between a one-way clutch for forward movement and a one-way clutch for reverse movement.

(Embodiments) The present invention will be described in detail below based on drawings showing embodiments thereof. Fig. 1 is a longitudinal sectional view of a four-wheel drive power transmission device (hereinafter referred to as the device of the present invention) according to the present invention.

In the figure, 1 is a main drive shaft whose one end is connected to the output end of the engine and the other end is connected to the main drive wheel and rotates in conjunction with the main drive wheel, and 2 is the main drive shaft which is connected to the slave drive wheel. This is a driven gear fitted to a driven driven shaft (not shown). The following explanation will be given for the case where the main drive wheel (front wheel) driven by the main drive shaft 1 is the wheel on the side to be steered, as in a general four-wheel drive vehicle based on a front-wheel drive vehicle. However, the scope of application of the device of the present invention is not limited to this.

When the front wheel is the main drive wheel and also the steered wheel, the device of the present invention drives the sub-drive shaft that rotates in conjunction with the non-steered wheel (rear wheel) through the sub-drive gear 2 only when the sub-drive shaft rotates in advance. a pair of one-way clutches 3.4 connected to the shaft 1 and interposed between the main drive shaft 1 and the slave drive gear 2;
A cam mechanism 5 is provided on the main drive shaft l to operate as described later to perform these switching operations.

The one-way clutches 3.4 shown in the drawings were all proposed by the applicant of the present application, and were published in Japanese Patent Publication No. 46-21126 and Japanese Patent Publication No. 51
-21093 and Japanese Patent Publication No. 55-36852, the inner ring 30°40 and the outer ring 31.41 are configured in the shape of a conical roller bearing, and between the raceway surfaces, one of which has a hyperbolic cross section, the two wheels are A plurality of sprags 32.4 that are inclined at a predetermined angle with respect to the axis of the sprags 32.
2 is interposed between the inner ring 30.4'O and the outer rings 31, 41 to satisfy a predetermined positional relationship in the axial direction, and it functions only when the sprags 32.42 are brought into contact with their respective raceway surfaces. The structure is as follows. - the inner ring 30.40 of each of the directional clutches 3.4 is fitted onto the main drive shaft 1 and is engaged with a respective key 33.43 embedded in its outer periphery;
Further, the outer rings 31 and 41 are arranged coaxially on the outside of the main drive shaft 1, and are fixed to the transmission gear 6 that meshes with the slave drive gear 2 in such a manner as to sandwich it from both sides. As a result, the inner ring 30.40 rotates in conjunction with the main drive shaft 1, and the outer ring 31.41 rotates in conjunction with the slave drive gear 2, that is, the slave drive shaft. Further, the one-way clutches 3.4 are arranged in opposite directions as shown in the figure so that they function in different rotational directions of the main drive shaft 1 during forward movement and reverse movement. Now, the one-way clutch arranged like this 3.
The cam mechanism 5 that performs a switching operation between the inner ring 30 and the inner ring 30
．． A disk-shaped substrate 50 is integrally provided around the middle part of the main drive shaft 1 between the outer fitting positions of 40, and one surface of each of the two sides of the substrate 50 is opposed to the main drive shaft 1 in the axial length direction. A pair of disk-shaped pressing plates 51 and 52 are slidably fitted onto the outside of the press plate. The other surfaces of these pressing plates 51, 52 are in contact with one side of the inner ring 30, 40, respectively, and the other side of these inner rings 30, 40 is attached to the outer periphery of the main drive shaft l. Disc springs 35 and 45 are interposed between the respective retaining rings 34 and 44 and are in elastic contact with each other.

2 is a plan view of the base Fi, 50 taken along line nn in FIG. 1, and FIGS. 3 and 4 are enlarged views of essential parts for explaining the operation of the cam mechanism 5.

As shown in the figure, on both sides of the substrate 50, a plurality of rectangular recesses 53, 53, whose longitudinal direction is the circumferential direction, are equally spaced on a predetermined circumference centered on the axis thereof. A cam ball 54, 54, . These cam balls 54, 54... are inserted into the respective recesses 53, 53.
The recesses 53, 53... are biased in the longitudinal direction by separate coil springs 55, 55... interposed between the short sides of the recesses 53, 53.... However, coil spring 55.55・
The direction of the bias is different on both sides of the substrate 50, as shown in FIG. In FIG. 2, for convenience of illustration, the formation positions of the recesses 53, 53, . . . on both sides of the substrate 50 are shown shifted in the circumferential direction, but as shown in FIG. ... may be aligned with each other, and the number of recesses 53, 53... is not limited to four on each side of the substrate 50, as shown in FIG. 2, but may be three or more. Good to have.

On the other hand, pressing plates 51 .
52 has the recesses 53, 53 and 52 on the surface facing the substrate 50.
Rectangular recesses 56, 56, . . . corresponding to the respective ones are formed. As shown in the figure, these recesses 56, 56...
The bottom surface of each of the coil springs 55, 55, . . . in the opposing recesses 53, 53, . As mentioned above, the coil springs 55.5 in the recesses 53, 53 on both sides of the board 50
Since the intervening positions of 5 and 5 are opposite to each other, as shown in FIG. It's the other way around.

Now, the operation of the cam mechanism 5 constructed as above will be explained with reference to FIGS. 3 and 4. As described above, the substrate 50 is constructed integrally with the main drive shaft 1 and rotates with the rotation of the main drive shaft 1, whereas the press plate 51 is not restrained from rotating by the main drive shaft 1.

Further, the pressing plate 51 is constantly pushed to the base trIi50 via the inner ring 30 of the one-way clutch 3 by the spring force of the device spring 35.
is being pushed towards. Therefore, when the main drive shaft 1 rotates counterclockwise when viewed from the one-way clutch 3 side, as shown by the solid arrow in FIG. At this time, the cam ball 54 housed in the recess 53 moves in the direction shown by the mark.
6 and restrains the movement of the press plate 51,
The pressing plate 51 is held relative to the substrate 50 with a gap corresponding to the diameter of the cam ball 54 between the bottom surfaces of the recesses 53 and 56. On the other hand, when the main drive shaft 1 rotates clockwise when viewed from the one-way clutch 3 side, as indicated by the broken line arrow in FIG. Try to move in the direction indicated by the arrow. In this case, the cam ball 54 housed in the recess 53 comes to abut on the inclined surface of the recess 56 as it moves, and as a result of this abutment, a white arrow mark appears on the press plate 51. The board 5 as shown in
A pressing force acts in a direction away from 0, and the pressing plate 51 resists the urging force of the device spring 35 and moves toward the base vi50.
It slides on the main drive shaft 1 in the direction of being separated from the main drive shaft 1, and presses the inner ring 30 of the one-way clutch 3 in the same direction. The one-way clutch 3 is assembled at the stage of assembly, that is, the disc spring 35
There is a slight gap between the raceway surface of the outer ring 31 and the sprags 32 when the sprags 32 are pressed toward the base plate 50 by the spring force of the spring, and the inner ring 30 is pressed by the sliding of the pressing plate 51. Only when a predetermined positional relationship is satisfied between the inner ring 30 and the outer ring 31, a predetermined function can be performed. Due to the operation of the cam mechanism 5 as described above, the one-way clutch 3 is connected to the driven gear 2 only when the main drive shaft l rotates in the direction indicated by the dashed arrow in FIG. In this state, the main drive shaft l and the driven gear 2 are connected via the one-way clutch 3 only when the driven gear 2, which rotates in conjunction with the non-steered wheels, rotates in advance. It is directly connected and transmits power to the slave drive shaft.

The other pressing plate 52 in the cam mechanism 5 is also connected to the substrate 50
A similar operation is performed through the cam balls 54, 54... interposed between the cam balls 54, 54, etc., but the inclined surfaces of the recesses 56, 56... in the pressing force Fi, 52 are in the opposite direction to that of the pressing plate 51. Since it is tilted, the pressing plate 52 slides away from the base plate 50, and the inner ring 40 of the one-way clutch 4 accompanying this slides away from the base plate 50.
The movement occurs only when the main drive shaft 1 rotates in the direction indicated by the solid arrow (for example, when moving forward). Therefore, the one-way clutch 4 is interposed between the main drive shaft 1 and the driven gear 2 only when moving forward due to the operation of the cam mechanism 5, and the driven gear 2, which rotates in conjunction with the non-steered wheels, rotates both of them in advance. It has a direct effect when

As described above, in the device of the present invention, the forward one-way clutch 4 and the reverse one-way clutch 3 are automatically operated by the operation of the cam mechanism 5, which operates in different directions depending on the rotational direction of the main drive shaft 1. As a result, a simple configuration as shown in FIG. 1 is realized. Note that FIG. 1 shows the pressure plate 5.
2 shows a case where the one-way clutch 4 is in an operating state due to the operation of 2, and it goes without saying that in this case, the direction of rotation of the main drive shaft 10 is the direction indicated by the solid arrow.

Further, in this embodiment, the cam mechanism 5 is constructed on the main drive shaft 1, but the slave drive gear 2 is connected to the slave drive shaft.
is the main drive gear interlockingly connected to the main drive shaft, and the main drive shaft 1
It is also possible to adopt a configuration in which the one-way clutches 3 and 4 are switched by a cam mechanism 5 configured on the slave drive shaft, with the one-way clutches 3 and 4 being set as the slave drive shaft. However, in this case, the direction of power transmission in the one-way clutch 3.4 is different from the case of this embodiment, from the outer ring 31.41 side to the inner ring 30.40 side.

FIG. 5 is a longitudinal cross-sectional view of another embodiment of the device of the present invention constructed using a more common one-way clutch 7.8 such as a sprag clutch or a roller clutch. As is well known, in these one-way clutches 7.8, the inner ring 70.
Since it is not possible to achieve the respective functions by realizing a predetermined positional relationship between the pressing plate 51 and the outer ring 70.80 of the cam mechanism 5, the inner ring 70.
Friction plates 9 and 9 are respectively attached to the opposing surfaces of the inner rings 70 and 80, and these are pressed against the opposing surfaces of the inner rings 70 and 80 by the aforementioned sliding motion of the pressing plates 51 and 52, and this frictional force causes the inner rings 70 and 80 to
The structure is such that the substrate 50, that is, the main drive shaft l is connected. In addition, the pressing plates 51 and 52 have inner rings 7 facing each other.
0.80 and biased toward the substrate 50 by disc springs 75 and 85, respectively, interposed between the two. These disc springs75.
It goes without saying that 85 has the same effect as the disc springs 35, 45 in FIG. Also, one-way clutch 7°8
The inner ring 70.80 is supported on the main drive shaft 1 by separate metal bearings 76.86, and when the friction plate 9°9 is not pressed, the rotation of the inner ring 70.80 is the main drive shaft. None so that it is not constrained by axis 1.

〔effect〕

As detailed above, in the apparatus of the present invention, the former.

Switching between the forward one-way clutch and the reverse one-way clutch interposed between the rear wheels is possible regardless of whether the shift lever is operated. Due to the operation of the cam mechanism constructed on the shaft, these operations are automatically performed according to the direction of rotation, making it possible to perform reliable switching operations with a simple configuration, which is significantly faster than conventional methods. The present invention has excellent effects such as a reduction in the number of parts and a reduction in the number of assembly steps, and there is no difficulty in securing the installation position.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the device of the present invention, FIG. 2 is a plan view of a substrate of a cam mechanism that performs clutch switching operation,
3 and 4 are explanatory diagrams of the operation of the cam mechanism, and FIG. 5 is a longitudinal sectional view showing another embodiment of the device of the present invention. 1... Main drive shaft 2... Slave drive gear 3.4.
・One-way clutch 5 ・Cam mechanism 7.8・
... - direction clutch 50 ... board 51.52.
... Pressing plate 53, 56 ... Concave portion 54 ... Cam ball 55 ... Coil spring patent Applicant Koyo Seiko Co., Ltd. Agent Patent attorney Noboru Kono Figure Figure Figure

Claims (1)

[Scope of Claims] 1. Between a main drive shaft that rotates in conjunction with one of the front and rear wheels and a subordinate drive shaft that rotates in conjunction with the other, there is provided a shaft that rotates when the wheel on the side that is steered among the two wheels moves forward; A four-wheel drive drive coupling device that includes a pair of one-way clutches that each allow forward rotation during reversing, and selectively switches these clutches depending on the direction of travel, comprising: A power transmission device for four-wheel drive, comprising a cam mechanism configured to operate in different directions in the axial direction depending on these rotational directions and to switch to each of the one-way clutches.