JPH03326A - Drive connection device for four-wheel drive - Google Patents

Abstract

PURPOSE:To simplify the construction of a choke means provided on the delivery side of a pump chamber by providing an opening and closing means with a spool, closely fitted in the middle of a connecting hole for connecting the delivery side of the pump chamber to a low pressure portion and slid by receiving hydraulic pressure on one side of it, and for opening and closing the connecting hole according to the slide of the spool. CONSTITUTION:In an opening and closing means 5, the sliding position of a spool 50 is determined by a balance of a hydraulic pressure in a circular groove 24 acting on one side, i.e., the hydraulic pressure on the delivery side of a pump chamber with the energizing force of a coil spring 52 acting on the other side. When the hydraulic pressure is low and a force acting on the spool 50 is lower than the energizing force of the spring 52, a clearance is kept between the mating surfaces of the spool 50 and the stopper 51 and an opening end of an oil feeding hole 50a into an oil tank T is opened. On the other hand, when the hydraulic pressure is higher than the energizing force of a spring 52, the spool 50 is started to slide to the stopper 51 until the disk portion of the spool 50 are made in contact with the cylindrical part end surface of the stopper 51 to suppress the slide movement. Namely, the means 5 serves to open and close a connection hole 47.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention realizes a four-wheel drive state by distributing driving force to both wheels using the hydraulic pressure generated by a hydraulic pump installed between the front and rear wheels. The present invention relates to a four-wheel drive drive coupling device.

[Prior art]

Drives by transmitting the engine's driving force to both the front and rear wheels 4
Wheel drive vehicles have been attracting attention as vehicles that can achieve high running stability and comfortable driving regardless of road surface conditions and driving conditions. A four-wheel drive vehicle is basically achieved by directly connecting each of the front and rear wheels to the engine that is the drive source, but in this case, it is impossible to absorb the difference in rotational speed that occurs between the two wheels. Due to the occurrence of the so-called tight corner braking phenomenon, the vehicle exhibits unusual behavior when cornering, making it difficult for ordinary drivers to handle. Therefore, in recent years, so-called full-time four-wheel drive vehicles have become mainstream, equipped with a drive coupling device that absorbs the difference in rotational speed that occurs between the front and rear wheels and distributes driving force to both wheels according to this difference in rotational speed. As one of these drive coupling devices, one that utilizes the hydraulic pressure generated by a hydraulic pump has been developed.

This drive coupling device is, for example, a differential gear device (center differential) installed midway in the transmission system from the engine to the front and rear wheels.
A differential limiting section is attached to this, which limits the differential with a force corresponding to the rotational speed difference between the front and rear wheels.
The hydraulic pressure generated by a hydraulic pump is used as means for generating the limiting force in this differential limiting section. As is well known, a differential gear device is constructed by meshing a plurality of planetary gears, each of which rotates independently while revolving on a common axis of revolution, with a pair of differential gears. It is a mechanical element that is distributed to different output ends that are individually interlocked with a gear, and the difference in rotational speed that occurs between the output ends is absorbed by the rotation of the planetary gear, so that the transmission to the output ends that have different rotational speeds is possible. is possible. Therefore, by interlocking the revolving shaft of the planetary gear with the engine and providing a differential gear device (center differential) in which a pair of differential gears are interlockingly connected to the front and rear wheels, it is possible to A four-wheel drive vehicle is constructed that can transmit the driving force of the engine to both wheels while absorbing the difference in rotational speed.

However, the differential gear device has a driving force input to it that is
Because it has a transmission characteristic that distributes more driving force to the side with higher rotational speed when distributing it to the two output ends,
In a four-wheel drive vehicle configured as described above using this differential gear device, when one of the front and rear wheels is in a idling state,
Most of the driving force generated by the engine flows to this idling side and grips the road surface, causing the inconvenience that only a small amount of driving force is transmitted to the non-idling side which requires driving force.

The differential limiting section applies a limiting force between the pair of differential gears of the differential gear device corresponding to the magnitude of the differential between the two, and distributes a driving force greater than a predetermined value to the side with the lower rotational speed. This differential limiting section, which utilizes the hydraulic pressure generated by a hydraulic pump, has a casing that rotates in conjunction with one of the differential gears, that is, one of the front and rear wheels, and a casing that is housed inside the casing. One rotor rotates in conjunction with the other, and a pump chamber is formed between the two. With this configuration, a relative rotation occurs between the casing and the rotor corresponding to the difference in rotational speed between the front and rear wheels, and a hydraulic pressure is generated inside the pump chamber that increases or decreases depending on the magnitude of this relative rotation. This generated hydraulic pressure acts within the pump chamber to suppress the relative rotation between the casing and rotor, and as a result, the amount of transmission driving force distributed to the front and rear wheels, respectively, increases. It is determined using the oil pressure as a medium for equalization, and a desired four-wheel drive state is achieved. Note that in this differential limiting portion, since the casing and rotor rotate together, it is difficult to supply hydraulic oil from an oil tank fixedly provided outside. Therefore, an oil storage part for sealing hydraulic oil is integrally provided in a part of the casing, and a suction oil passage and a discharge oil passage formed in a part of the casing and the rotor are connected between the oil storage part and the pump chamber. The sealed oil in the oil storage part is communicated with the oil storage part so that the oil sealed in the oil storage part can be circulated and used.

Now, in a four-wheel drive vehicle, in order to suppress the occurrence of the tight corner braking phenomenon as much as possible, there is a possibility that the front and rear wheels may be In the range where the rotational speed difference between the front and rear wheels is large, such as when a loose connection state is obtained and one of the front and rear wheels is in a state of idling, conversely, the connection state between the front and rear wheels is large. There is a strong need for transmission characteristics that provide a rigid connection state. Such characteristics cause the hydraulic pressure generated by the hydraulic pump constituting the differential 17111 to gradually increase as the rotational speed difference increases until the rotational speed difference between the front and rear wheels reaches a predetermined size. This is achieved by rapidly increasing the rotational speed as the difference in rotational speed increases after the predetermined value is exceeded. The applicant has proposed that the hydraulic pressure inside the pump chamber is generated against the flow resistance in the communication path between the pump chamber and the oil storage section,
Focusing on the fact that the increase rate changes depending on the degree of restriction of the communication passage, a four-wheel drive drive coupling device using a hydraulic pump capable of generating hydraulic pressure as described above was proposed in Japanese Patent Application No. 63-2.
This was proposed in No. 77020 and Utility Model Application No. 1-31601.

FIGS. 8 and 9 are enlarged sectional views of essential parts showing the configuration of the characteristic parts of this drive coupling device. This drive coupling device is characterized in that a throttle means 7 as shown is provided in the middle of a communication hole 47 that communicates between the discharge side of the pump chamber and the oil storage section maintained at a low pressure. . The throttle means 7 includes a spool 70 that receives discharge pressure, and restriction members 71 and 72 that restrict movement of the spool 70. The communication hole 47 has a large diameter portion on the oil storage side, and one of the restriction members 71 is connected to a guide rod 71a erected at the axial position of the restriction member 71.
is press-fitted and fixed to the discharge side end of the large diameter part, with the main body facing toward the oil storage part. The spool 70 is a cylindrical member with a bottom, and is slidably fitted onto the guide rod 71a.
The oil pressure on the discharge side acts on the inner bottom surface of the guide rod 71a through an oil guide hole 71b that passes through the axial center position of the guide rod 71a in the axial direction. The other limiting member 72 in the shape of a hollow disc is
It is fitted into the large diameter portion of the communication hole 47 at a position close to the oil storage portion, and
A coil spring 74 that biases the spool 70 toward the discharge side is interposed between the limiting member 72 and the spool 70, and the movement of the limiting member 72 due to the reaction of this biasing It is restrained by a snap ring 73 attached to the inner periphery of the section. The spool 70 has an oil passage hole 70a that penetrates the peripheral wall of the spool inward and outward, and the restriction member 71 has an annular groove 70 that communicates with the oil passage hole 71b through the oil passage hole 71d.
1c on the outer peripheral surface of the guide rod 71a, and the annular groove 7
The opening state of the oil passage hole 70a in 1c changes according to the sliding movement of the spool 70.

With the above configuration, the oil discharged from the pump chamber into the communication hole 47 is transferred to the oil guide hole 71b, the oil passage hole 71d, and the annular groove 7.
1c and the oil passage hole 70a, it flows out to the outside of the spool 70, and further flows through the hollow part of the restriction member 72 to the oil storage part. The sliding position of the spool 70 at this time is determined by the balance between the hydraulic pressure acting on the internal bottom surface of the spool 70, that is, the hydraulic pressure generated inside the pump chamber and the biasing force of the coil spring 74.
When the oil pressure is low and less than the biasing force of the coil spring 74, the spool 70 is moved by the limiting member 7 as shown in FIG.
1, and the oil passage hole 70a is fully opened. On the other hand, when the oil pressure is sufficiently high, the spool 70 is pressed against the restriction member 72, and the oil passage hole 70a is fully closed, as shown in FIG. Become. As mentioned above, the rate of increase in the hydraulic pressure generated inside the pump chamber corresponds to the flow resistance on the discharge side, and the magnitude of the flow resistance is 1. This corresponds to the size of the opening area of the oil passage hole 70a. Therefore, in a hydraulic pump equipped with the throttle means 7 having such a configuration, the relative rotational speed between the casing and the rotor, that is, the rotational speed difference between the front and rear wheels is small (in a range in which no sliding of the spool 70 occurs). In this case, a hydraulic pressure that gradually increases as the speed difference increases is obtained.After this hydraulic pressure reaches a predetermined value and the spool 70 starts sliding, the rotational speed difference increases and the generated hydraulic pressure increases. As the rotation speed increases, the opening area of the oil passage hole 70a decreases, and the increase in flow resistance accompanying this area reduction promotes the increase in the generated oil pressure.As a result, the oil pressure increases rapidly as the rotation speed increases. As a result, in the range of relatively small rotational speed differences expected during cornering, a loose connection between the front and rear wheels is obtained, and one of the front and rear wheels is prevented from idling. In a range where the difference in rotational speed between the front and rear wheels is large, such as when the above-mentioned condition is reached, desired transmission characteristics such as a connection state as rigid as possible between the two wheels can be achieved. The extremely small diameter throttle hole 70b formed at the center of the bottom of the spool 70 is provided to ensure the minimum flow when the oil passage hole 70a is in a fully closed state, and is located near the periphery of the restriction member 72. Through holes 72a, 72a formed
are provided to prevent trapping of hydraulic oil within the large diameter portion when fully closed, and these improve responsiveness when the spool 70 slides.

[Problem to be solved by the invention]

Now, the four-wheel drive drive coupling device is installed in a limited space in the middle of the transmission system to the front and rear wheels, and is required to be as compact as possible. The throttle means 7 configured as described above includes a spool 70 and a limiting member 71 that guides the sliding movement of the spool 70 and limits the sliding range.
Since it requires a large number of components and a considerable amount of installation space, its provision has the drawback of running counter to the demand for miniaturization of drive coupling devices.

In addition, the throttle means 7 includes an oil passage hole 70a formed in the spool 71 and a guide rod 71a that guides the spool 71.
Since the aperture opening degree is changed by relative movement with the annular groove 71c on the outer periphery, high positional accuracy is required when forming the oil passage hole 70a and the annular groove 71c.
High machining accuracy is required for each part of the component parts, such as the sliding contact part between the guide rod 71a and the large diameter part of the limiting member 71, and a large number of machining steps are required.

The present invention has been made in view of the above circumstances, and provides a four-wheeled construction that simplifies the configuration of the throttling means provided on the discharge side of the pump chamber in order to obtain desired transmission characteristics, and that enables miniaturization and reduction of processing man-hours. It is an object of the present invention to provide a drive coupling device for a drive.

[Means to solve the problem]

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

It includes a casing that rotates in conjunction with one of the rear wheels, and a rotor that is housed inside the casing and rotates in conjunction with the other, and distributes driving force using the hydraulic pressure generated inside the pump chamber formed between the two. In a four-wheel drive drive coupling device,
A spool is fitted in the middle of a communication hole that communicates the discharge side of the pump chamber with a low pressure section and receives the hydraulic pressure on one side of the spool and slides, and opens and closes the communication hole in response to this sliding. It is characterized by comprising an opening/closing means.

[Effect]

In the present invention, a spool fitted in a communication hole that communicates the discharge side of the pump chamber with the oil storage section receives pressure on the discharge side and slides along the communication hole, and the communication hole is connected to the communication hole. It is opened and closed by sliding, changing the flow resistance on the discharge side of the pump chamber, and obtaining desired transmission characteristics.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof. FIG. 1 is a longitudinal sectional view showing an example of a four-wheel drive drive coupling device (hereinafter referred to as the device of the present invention) according to the present invention.

What is shown in this figure is a differential gear device 1 that distributes driving force to both wheels while absorbing the difference in rotational speed between the front and rear wheels.
The structure includes a differential limiting section 2 that limits the differential by the hydraulic pressure generated by the hydraulic pump, and the feature of the present invention lies in the structure of the differential limiting section 2.

First, the configuration and operation of the differential gear device 1 will be explained.

The differential gear device 1 shown in FIG. 1 is constructed using spur gears in order to shorten the axial length dimension. Reference numeral 10 in the figure indicates an input housing having a shape in which a large diameter cylindrical part is coaxially connected to one end of a small diameter cylindrical part. This input housing 1
0 is supported by a part of the vehicle body (not shown), and rotates around its axis by input from an engine (not shown) interlocked with the other end of the small diameter cylindrical portion. The first output shaft 11 of the differential gear device 1 is coaxially rotatably supported inside the input housing 10 by a tapered roller bearing 10a that is fitted and fixed in the small diameter cylindrical portion. The output shaft 12 is rotatably supported inside a fixed housing 13 coaxially with the input shaft housing 10 and fixed to a part of the vehicle body by a ball bearing 13a fitted and fixed therein. There is. The projecting end of the second output shaft 12 that projects externally from the fixed housing 13 is inserted a predetermined length into the input shaft housing 10 from the large-diameter cylindrical portion side, and is aligned on the axis of the projecting end. is a support hole 1 having an appropriate depth in the axial direction.
2a is formed. The end of the first output shaft 11 is inserted into the support hole 12a to a suitable length and supported by a needle roller bearing that is fitted and fixed in the hole 12a as shown. These first output shaft 11 and second output shaft 12 are interlocked and connected to the front wheels and the rear wheels, respectively. For example, the first output shaft 11 rotates at a speed corresponding to the rotational speed of the front wheels. The two output shafts 12 rotate on the same axis and in the same direction at a speed corresponding to the rotational speed of the rear wheels.

The large-diameter cylindrical portion of the input housing 100 is an internal gear 10b with a large number of teeth formed over the entire inner circumference, and the vicinity of the protruding end of the second output shaft 12 has an internal gear 10b formed over the entire outer circumference. The external gear 12b is formed with a large number of teeth, and the external gear 12b and the internal gear 10b are aligned in the axial direction. In the annular space formed between the internal gear 10b and the external gear 12b, a plurality of spur gears 14a, 14a... and spur gears 14b, 14 are arranged in the circumferential direction.
b... are interposed therein, among which the spur gears 14a, 14a... located on the radially outer side are connected to the internal gear 10b, and the spur gears 14b, 14a... are located on the radially inner side of the internal gear 10b.
4b... are respectively meshed with the external gears 12b, and adjacent gears are meshed with each other. Further, the spur gears 14a, 14a... and the spur gears 14b, 14b... are both held between the holding members 15, 16 located on both sides thereof. Second output shaft 1
1.12, and is rotatably supported around separate pivots parallel to 1.12. The holding member 15 on the side of the input housing 10 includes a cylindrical portion coaxially connected to the inner peripheral side of a hollow disc that pivotally supports the spur gears 14a and 14b. It is fitted onto the output shaft 11 of No. 1 and spline-coupled thereto. Therefore, the holding member 15 is attached to the first output shaft 1
Spur gears 14a and 14b rotate coaxially with the rotation of 1 and are rotatably supported on the holding member 15.
rotates around their respective pivot axes while revolving together with the holding member 15. The other holding member 1 is a hollow disc-shaped member having an outer diameter slightly larger than the holding member 15 and an inner diameter sufficiently larger than the outer diameter of the second output shaft 12.
6 is connected to the holding member 15 via the pivot shafts of the spur gears 14a and 14b, and is coaxially moved in conjunction with the rotation of the first output shaft 11 together with the holding member 15. Rotate. A large number of locking teeth 16a are formed on the outer peripheral surface of the holding member 16 over the entire circumference.
A is engaged with a casing of a differential limiting portion 2, which will be described later, on the outside of the large diameter portion of the input housing 10.

In the differential gear device 1 configured as described above, the driving force of the engine transmitted to the input housing 10 is transmitted through the internal gear 10b formed on the inner periphery of the large diameter portion of the housing 10;
The output is transmitted to the first output shaft 11 via the spur gears 14a, 14a... that mesh with this, and the holding member 15 that pivotally supports these, and the spur gear 14b that is further pivotally supported by the holding member 15.
, 14b..., and the external gear 12b meshing with these
is transmitted to the second output shaft 12 via. At this time, since the first output shaft 11 rotates in conjunction with the front wheels and the second output shaft 12 rotates in conjunction with the rear wheels, there are A differential corresponding to the rotational speed difference between the wheels occurs, and the differential between the first output shaft 11 and the input housing 10 is caused by the rotation of the spur gears 14a, 14a, etc. interposed between them. Also, 1st. The differential between the second output shafts 11.12 is absorbed by the rotation of the spur gears 14b, 14b... interposed between them, and the driving force is not transmitted from the input housing 1o to the output shafts 11.12. , regardless of whether or not the rotational speed difference exists. However, at this time, due to the characteristics of the differential gear device 1, the transmission ratio of the driving force from the input housing 10 to the first and second output shafts 11 and 12 varies depending on the speed of these rotations, and Among 11 and 12, more driving force is transmitted to the side with higher rotational speed. For example, if the front wheels are idling and the rotational speed of the first output shaft 11 is extremely high, and the rear wheels are rotationally restricted and the rotational speed of the second output shaft 12 is approximately 0. , input housing 10
There is a problem in that most of the driving force transmitted from the engine flows to the former, that is, the front wheels that are idling, and only a small amount of driving force is distributed to the latter, that is, the rear wheels that require supply of driving force.

The differential limiting section 2 includes a first output shaft 11 and a second output shaft 12.
When a rotational speed difference occurs between the differential gear device 1 and This is provided in order to suppress the above-mentioned driving force distribution operation and ensure the amount of driving force distributed to the side with a lower rotational speed. The differential limiting section 2 shown in the figure is formed using a vane pump, which is a type of hydraulic pump, and uses the hydraulic pressure generated inside the vane pump as the limiting force.
0 and the end of the fixed housing 13 on the second output shaft 12 .

FIG. 2 shows the structure of the main parts of the differential limiting section 2.
- It is a cross-sectional view taken along the m line. The differential limiting portion 2 includes a rotor in which cylindrical boss portions 21° 21 with a smaller diameter than the short cylindrical rotor main body 20 are coaxially arranged on both sides of the rotor main body 20 in the axial direction; and a casing in which the rotor is coaxially rotatably housed. A second rotor is provided between the input housing 10 and the fixed housing 13.
It is fitted onto the output shaft 12 of the output shaft 12 and is spline-coupled to the output shaft 12 so as to rotate in conjunction with the output shaft 12. The boss portions 21 and 21 are positioned in the axial direction by abutting the end surfaces of the stepped portion formed on the outside of the second output shaft 12, respectively.

As shown in FIG. 2, a plurality of grooves having a predetermined depth in the radial direction from the outer peripheral surface of the rotor body 20 are formed at approximately equal intervals in the circumferential direction. To,
Vanes 22, 22, . . . having a rectangular plate shape are inserted so as to be freely movable in the radial direction. As shown in FIG. 1, a coil spring 23 is interposed between the base of each vane 22 and the bottom of each storage groove, and the bottoms of all storage grooves are connected to both sides of the rotor body 200. Annular groove 24.2 formed
4, and each vane 22 is connected to the biasing force of each separate coil spring 23 and the annular groove 24.
, 24 into the bottom of each storage groove as will be described later.

On the other hand, the casing in which the rotor with such a configuration is housed has a plurality of protrusions (three in this figure) on the circumference of a circle having an inner diameter slightly larger than the outer diameter of the rotor body 20. The rotor body 2 has a circular inner periphery and a circular outer periphery, and has an axial cross-sectional shape as shown in FIG.
A cam ring 3 having an uneven wall cylindrical shape and having an axial length that is approximately equal to 0.
Side plates 31 and 32 are coaxially integrated on both sides of 0. As shown in FIG. 1, one side plate 31 is a hollow disc-shaped member having an outer diameter approximately equal to that of the cam ring 30, and the other side plate 32
is a member having a shape in which a short cylinder with a small diameter that projects in the axial direction - side is connected to the radially inner side of a hollow disc having an outer diameter approximately equal to that of the cam ring 30, and this cylindrical part has a A holding member 33 in the form of a hollow disc is fitted onto the outside. Side plates 31 , 32 are positioned on both sides of the cam ring 30 coaxially with the side plates 31 , 32 .
They are integrated with a plurality of fixing bolts 34, 34... that pass through this and the cam ring 30 from the side in order and are screwed into screw holes formed in the disc part of the side plate 32 and the presser member 33. , the casing is configured.

As shown in FIG. 1, the rotor has boss portions 21.21 protruding from both sides of the rotor body 20 and side plates 31.3.
The rotor main body 20 is fitted into the hollow portions of the casings 2 and 2, and the rotor main body 20 is positioned coaxially within a cavity surrounded by the inner peripheral surface of the cam ring 30 and the side surfaces of the side plates 31 and 32. It is stored inside. At this time, the outer periphery of the boss portion 21.21 is connected to the side plate 31.
．． The rotor and the casing are each sealed with a shaft sealing member such as an oil seal that is fitted and fixed in the hollow portion of the rotor 32 and protrudes to the outside of the casing by an appropriate length, and the positioning of the rotor and the casing in the axial direction is as described above. The boss portion 21.21 is connected to the ball bearing 13.
This is done by sandwiching it between the stepped portion of the second output shaft 12 and the stepped portion of the second output shaft 12. Further, among the constituent members of the casing, the holding member 33 located on the differential gear 1 side protrudes in the axial direction toward the differential gear Wl side, and has a large number of parts extending over the entire circumference of its end surface. It has an annular portion formed with locking teeth 33a near the outer periphery, and these locking teeth 33a are
It is engaged with the locking teeth L6a on the outer periphery of the holding member 16 in the differential gear device 1.

As a result, the casing of the differential limiting portion 2 is secured to the holding member 16.
and a plurality of spur gears 14a, 14b held therein.
The other holding member 1 of the differential gear device 1 via the pivot shaft of
5, and rotates at a rotational speed of the holding member 15, that is, at a speed equal to the rotational speed of the first output shaft 11 of the differential gear device 1.

Now, as described above, inside the casing housing the rotor body 20, each of the formation positions of the convex portions on the inner circumference of the cam ring 30 is surrounded by the outer circumferential surface of the rotor body 20 and the inner circumferential surface of the cam ring 30. A plurality of pump chambers 40 (three in this embodiment) each having a deformed crescent shape as shown in FIG.
, 40.40 are formed. Pump chamber 40, 40.40
is equipped with a pair of suction ports 41, 41 that open toward the side plate 32 at both ends in the circumferential direction, and these suction ports 41, 41... Separate suction holes 42, 42... passing through in the horizontal direction
This allows the side plate 32 and the holding member 33 to communicate with an oil tank T, which is a hydraulic oil reservoir, formed as shown in FIG. 1. A suction check valve 43 that only allows inflow from the kernel oil tank T to the respective pump chamber 40 is fitted into the communication portion of each suction hole 42 with the oil tank T.

That is, the suction hole 42 allows suction into the pump chamber 40 only when the internal pressure of the pump chamber 40 becomes lower than the internal pressure of the oil tank T at the opening position of the corresponding suction port 41 and the suction check valve 43 is opened. Functions as an oil channel.

Further, as shown in FIG. 2, the rotor body 20 has a discharge hole 4 which opens between the mounting positions of the adjacent vanes 21, 21 on the outer peripheral surface thereof and has a predetermined depth in the radial direction.
4.44... is formed. The bottom of each discharge hole 44 is communicated with the annular grooves 24 and 24 formed on both sides of the rotor body 20 through separate oil guide holes 45 that pass through the rotor body 20 in the axial direction, and each In the middle of the discharge hole 44, there is a radially inward flow, that is, a pump chamber 40.
A discharge check valve 46 is fitted in each case to allow only outflow from the discharge valve. Furthermore, among the annular grooves 24.24, the annular groove 24 on the side plate 32 side is
It is communicated with the oil tank T through a pair of communication holes 47 and 47 that penetrate through it in the thickness direction. That is, the pump chamber 4
0.40.40 is for each separate discharge hole 44 and accompanying oil guide hole 45, as well as the common annular groove 24 and communication hole 4.
It is connected to the oil tank T by an oil passage consisting of 7.47, and among these, each discharge hole 44 and the oil guide hole 45 attached thereto are as follows:
When the internal pressure of the pump chamber 40 at the opening position of the discharge hole 44 exceeds the internal pressure of the annular groove 24 that communicates all the discharge holes 44, 44, etc., and each discharge valve 46 is opened. The annular groove 24 and the communication hole 47 always function as a discharge oil passage.

In the device of the present invention, an opening/closing means 5 is provided in the middle of a communication hole 47.
．． 6 are respectively attached, and the structure of these opening/closing means 5 and 6 is distinctive. The opening/closing means 5 and the opening/closing means 6 perform different functions, and FIGS. 3 and 4 show enlarged sectional views of one opening/closing means 5, and FIGS. 5 and 6 show the other opening/closing means 6. An enlarged cross-sectional view of each is shown.

As shown in these figures, the communication hole 47 is connected to the annular groove 24.
The small-diameter hole 47a on the side and the large-diameter hole 47b on the oil tank side are coaxially connected, and one opening/closing means 5 attached to this communication hole 47 is as shown in FIGS. 3 and 4. , a spool 50 that moves by receiving hydraulic pressure on the discharge side of the pump chamber 40, and a stopper 51 that limits the range of movement of the spool 50, which are connected by a coil spring 52 interposed between the two.
They are biased in directions away from each other.

The spool 50 has a shape in which a cylindrical body with a smaller diameter is coaxially connected to one side of a thin circular plate, and at the axial center position,
An oil passage hole 50a penetrating in the axial direction is formed. The cylindrical part of the spool 50 is fitted into the small diameter hole 47a with its end face facing the annular groove 24 side,
The spool 50 is guided by this fitting portion and slides in the axial direction. Also at this time, spool 5
The disk portion of 0 is loosely inserted into the large diameter hole 47b,
The oil passage hole 50a has a constricted portion machined to have a small diameter on the disk side, that is, on the opening side into the oil tank T. on the other hand,
Like the spool 50, the stopper 51 has a shape in which a small-diameter cylinder is connected to one side of a disc, and the disc part is brought into contact with a part of the holding member 33, and the end face of the cylinder part is brought into contact with the spool 50. It is fixedly installed on the oil tank side so as to face the disc part. The coil spring 52 is loosely fitted on the outside of the cylindrical portion of the stopper 5I, and both ends of the coil spring 52 are
The disk portion of the spool 50 and the disk portion of the stopper 51 are pressed into contact with each other, so that a predetermined biasing force is applied between them in the direction of separating them from each other.

In the opening/closing means 5 configured as above, the sliding position of the spool 50 is determined by the hydraulic pressure in the annular groove 24 acting on the negative side.
That is, it is determined by the balance between the hydraulic pressure on the discharge side of the pump chamber 4o and the biasing force of the coil spring 52 acting on the other side,
When the oil pressure is low and the force acting on the spool 50 is less than the biasing force of the coil spring 52, the spool 50 is in the position shown in FIG. A gap is secured, and the opening end of the oil passage hole 50a into the oil tank T is in an open state. On the other hand, as the oil pressure exceeds the biasing force of the coil spring 52, the stopper 50 starts sliding toward the stopper 51, and this sliding occurs between the disk portion of the spool 50 and the end surface of the cylindrical portion of the stopper 51. This occurs as the oil pressure increases until it is suppressed by contact. When the contact occurs, the opening end of the oil passage hole 50a into the oil tank T is closed by the end face of the stopper 51, as shown in FIG. communication is cut off. That is, the opening/closing means 5 opens the communication hole 47 when the oil pressure in the annular a24 is low;
When the oil pressure is high, the communication hole 47 is closed. Note that the passage area of the communication hole 47 is controlled by the area of the constricted portion at the end of the oil passage hole 50a, so the sliding movement causes the spool 50 and the spool 7 bar 51 to come sufficiently close to each other. During this period, the passage area remains substantially constant regardless of the sliding position of the spool 50, and then rapidly decreases until it is closed.

As shown in FIGS. 5 and 6, the other opening/closing means 6 also has a spool 60 that moves by receiving hydraulic pressure on the discharge side of the pump chamber 40 and limits the range of movement of the spool 50, similar to the opening/closing means 5. The outer diameter shapes of the spool 60 and the stopper 61, the manner in which they are attached, and the manner in which they are attached are The manner in which the coil spring 62 is interposed therebetween is also exactly the same as that of the opening/closing means 5. Furthermore, the sliding movement of the spool 60 of the opening/closing means 6 is also similar to that of the opening/closing means 5, and the sliding position of the spool 60 is determined by the hydraulic pressure in the annular groove 24 acting on the negative side thereof, i.e. It is determined by the balance between the hydraulic pressure on the discharge side of the pump chamber 40 and the biasing force of the coil spring 62 acting on the other side, and when the hydraulic pressure is low and below the biasing force of the coil spring 62, the spool 6o 5, the oil pressure exceeds the biasing force of the coil spring 62 and starts sliding towards the stopper 61. This occurs as the oil pressure increases until it is inhibited by contact with the oil pressure.

However, the oil passage hole 60a in the spool 60 is different from the oil passage hole 50a in the spool 50, for example,
Fifth. As shown in FIG. 6, a hole is formed at the axial center position of the cylindrical portion of the spool 6o with an appropriate depth in the axial direction from the end surface of the cylindrical portion, and a hole is formed so as to intersect with the bottom of the hole. and a hole formed from the outside of the cylindrical part toward the axis.
It is a bent hole in the shape of a letter. As a result, the oil passage hole 60a
The open end of the outer periphery of the cylindrical part is completely closed by the inner peripheral surface of the small diameter hole 47a when the spool 60 is in the sliding position shown in FIG. 5, and conversely, in the sliding position shown in FIG. In other words, when the spool 60 comes into contact with the stopper 61, the interior of the oil tank T is completely opened. That is, the opening/closing means 6, contrary to the opening/closing means 5, closes the communication hole 47 when the oil pressure in the annular groove 24 is low, and opens the communication hole 47 when the oil pressure is high. In addition, the coil spring 6 of the opening/closing means 6
2 has a sufficiently larger spring constant than the coil spring 52 of the opening/closing means 5, and the spool 6
The zero sliding occurs after the spool 50 contacts the stopper 51.

The opening/closing means 5 and the opening/closing means 6 configured in this manner have a simplified structure and a significantly smaller size than the aforementioned throttle means 7, which is provided to obtain desired transmission characteristics in a conventional drive coupling device. It is clear from a comparison of FIGS. 3 to 6 and FIG. 8.9 that this can be achieved, and high machining accuracy is also required when machining the component parts of the opening/closing means 5.6. The only part that needs to be removed is the part where the spool 50, 60 and the communication hole 47 fit, and the number of processing steps can be significantly reduced.

Next, it will be explained in accordance with the operation of the differential limiting section 2 that by providing such opening/closing means 5 and 6, the desired transmission characteristics as described above can be obtained. As mentioned above, the casing of the differential limiting section 2 rotates in conjunction with the first output shaft 11, and the rotor rotates in conjunction with the second output shaft 12, but there is no difference in rotational speed between the front and rear wheels. First, when the rotational speeds of both output shafts 11, 12 are equal, the rotor and the casing rotate at the same speed, and no pumping action is performed in the differential limiting section 2. Therefore, at this time, the driving force transmitted to the input housing 1o is caused by the above-described operation of the differential gear device 1.
The signal is equally distributed and transmitted to the first output shaft 11 and the second output shaft 12.

On the other hand, when there is a difference in rotational speed between the front and rear wheels, that is, between the first output shaft 11 and the second output shaft 12, the differential limiting section 2 has a case that rotates in conjunction with the former. Relative rotation occurs between the single and the rotor that rotates in conjunction with the latter at a speed corresponding to the rotational speed difference. As shown in FIG. 2, vanes 22, 22,
The tips of the vanes 22, 22, and so on are pressed against the inner circumferential surface of the cam ring 30 by the biasing force of the coil spring 23, and when the relative rotation occurs, these vanes 22, 22, and so on are stored separately. It rotates with the rotation of the rotor while moving forward and backward in the radial direction along the groove, and the hydraulic oil in each pump chamber 40, 40.40 is sealed between two adjacent vanes 22.22. The rotor rotates as the rotor rotates. As a result, inside each pump chamber 40, 40, 40, the pressure decreases due to the expansion of the volume of the sealed space on the upstream side in the relative rotation direction, and decreases in the volume of the sealed space on the downstream side. The pressure rises accordingly, and the suction hole 42 connected to the suction port 41 that opens on the former side becomes a suction oil passage when the suction check valve 43 opens as the internal pressure decreases, and the suction hole 42 that connects to the suction port 41 that opens on the former side becomes a suction oil passage, and the inside of the pump chamber 40 on the latter side The discharge hole 44 that opens at the bottom of the discharge hole 44 and the oil guide hole 45 connected to the bottom thereof become a discharge oil passage when the discharge check valve 46 is opened as the internal pressure increases. For example, when the relative rotation occurs in the direction shown by the white arrow in FIG. The sealed oil in the oil tank T is introduced into the pump chamber 40 through this suction hole 42, and is sealed between the vanes 22 and 22 and rotated to increase the pressure, and the oil is pumped into this sealed space. A discharge check valve 4 fitted into an open discharge hole 44
6 is opened, the oil is discharged through the discharge hole 44 and the oil guide hole 45, and then flows into the annular grooves 24 and 24 on both sides of the rotor body 20.
be introduced within. The annular groove 24.24 is connected to the vane 22,2.
The annular groove 24 communicates with the bottom of the storage groove 2...
.

Due to such a pumping action of the differential limiting portion 2, hydraulic pressure is generated inside each pump chamber 40, 40, 40 against the flow resistance in the discharge oil passage. The magnitude of this flow resistance corresponds to the amount of oil delivered from the pump chamber 40, while the amount of delivered oil corresponds to the relative rotational speed between the rotor and the casing. The level of the generated oil pressure depends on the level of the relative rotational speed, that is, the first. The generated oil pressure corresponds to the magnitude of the difference in rotational speed between the second output shafts 11 and 12, and this generated oil pressure acts between the rotor and the casing to suppress relative rotation between the two. The difference in rotational speed between the two output shafts 11 and 12 is limited by the force that increases as this increases, and the amount of driving force distributed to both output shafts 11 and 12 is determined by using the hydraulic pressure to equalize them. This ensures that the driving force is transmitted to the front and rear wheels with the lower rotational speed.

Furthermore, in the device of the present invention, the hydraulic pressure generated inside the pump chamber 40 passes through the discharge hole 44, the oil guide hole 45, and the annular groove 24, and then passes through the opening/closing means 5, which is constructed in the middle of the communication hole 47.47.
．． 6 spools 50, 60, each of which slides as previously described. 1st. When the rotational speed difference between the second output shafts 11 and 12 is small and the hydraulic pressure generated in the pump chamber 40 is low, the opening/closing means 5 is in the open state, the opening/closing means 6 is in the closed state, and the pump chamber 40 is in the closed state. On the discharge side, spool 5
The pump chamber 40 is in communication with the oil tank T through the oil passage hole 50a formed in the oil passage hole 50a, and the flow resistance on the discharge side of the pump chamber 40 is dominated by the flow resistance at the oil passage hole 50a. . At this time, the hydraulic pressure generated within the pump chamber 40 increases relatively slowly with respect to the increase in the rotational speed difference. In this way, as the generated oil pressure increases, first the spool 5
0 starts sliding, and the opening/closing means 5 shifts to the closed state.

After the spool 50 slides, the passage area of the communication hole 47 rapidly decreases and closes just before the spool 50 is stopped by the stopper 51.
The recirculation resistance on the discharge side of the pump increases rapidly, and the hydraulic pressure inside the pump chamber 4o generated against this increases rapidly as the rotational speed difference increases. Due to this increase in oil pressure, the spool 60 then starts sliding, and the opening/closing means 6 shifts to the open state. When the spool 60 slides to a position sufficiently close to the stopper 61, the oil passage hole 60a formed in the spool 60 opens into the oil tank T, as described above, so that the oil pressure in the annular groove 24 is reduced. The hydraulic pressure generated in the pump chamber 40 is temporarily lowered by the opening in the tank T, and the oil passage hole 60 is opened by sliding the spool 60 in response to this.
a is closed again, and the spool 60 slides in the opening direction due to an increase in the hydraulic pressure generated in the pump chamber 40 caused by this closing, and the communication hole 47 is opened, causing a decrease in the generated hydraulic pressure. In this way, the opening/closing means 6 is configured such that after the opening/closing means 5 is closed, the hydraulic pressure generated in the pump chamber 40 is applied to the coil spring 6.
When the pressure exceeds a predetermined value determined depending on the locking property of the differential limiting portion 2, the oil is released into the oil tank T, and acts as a safety valve to prevent the pressure within the differential limiting portion 2 from rising excessively.

Figure 7 shows the 1. 7 is a graph showing how the pressure generated in the pump chamber 40 changes with respect to the change in the rotational speed difference between the second output shafts 11 and 12. FIG. As shown in this figure, in a range where the rotational speed difference is small, the opening/closing means 5 is in an open state, so that the pressure generated in the pump chamber 40 shows a tendency to gradually increase as the rotational speed difference increases. As the spool 50 that receives the generated pressure begins to slide, the rate of increase increases.Then, as the spool 50 and the stopper 51 come into contact with each other, the opening/closing means 5 becomes closed, and the order pressure in the pump chamber 40 rotates. It shows a tendency to rapidly increase as the speed difference increases. Furthermore, due to this rapid increase, when the generated oil pressure in the pump chamber 40 reaches a predetermined value, the spool 60 of the opening/closing means 6 starts sliding, and the subsequent operation of the spool 60 as described above causes the generated pressure in the pump chamber 40 to decrease. It is maintained substantially constant near the predetermined value. By obtaining such generated pressure in the pump chamber 40 of the differential uniform section 2, the first. Second
Between the output shafts 11 and 12, that is, in a range where the difference in rotational speed between the front and rear wheels is small, a relatively loose connection between the two wheels can be obtained, and in a range where the difference in rotational speed is large, it is possible to achieve a relatively loose connection between the two wheels. As mentioned above, a rigid connection state can be obtained, and such transmission characteristics are desirable characteristics in a four-wheel drive vehicle.

Note that the hydraulic pump constituting the differential limiting section 2 is not limited to the vane pump shown in this embodiment, but may also include a trochoid pump, etc.
Other hydraulic pumps may also be used, and the opening/closing means 5, 6
It goes without saying that the shapes of the spool 50.60 and the stopper 51.61 are not the same as those shown in this embodiment.

Furthermore, in this embodiment, a case has been described in which a hydraulic pump is used for the differential limiting section 2 that is attached to the differential gear device 1 and limits the operation of the differential gear device 1. A hydraulic pump is constructed between the drive wheel and the driven wheel, and the driving force corresponding to the hydraulic pressure generated in each pump chamber of the hydraulic pump according to the rotational speed difference between the two wheels is distributed to the driven wheel side. It can also be applied to a drive coupling device, and similar effects can be obtained.

〔effect〕

As described in detail above, in the device of the present invention, the flow resistance on the discharge side can be changed by operating the simply configured opening/closing means provided on the discharge side of the pump chamber that generates hydraulic pressure as a transmission medium for driving force. Therefore, the present invention has excellent effects, such as achieving desired transmission characteristics without contradicting the demand for overall miniaturization, and not requiring a large number of man-hours for processing and assembling the opening/closing means.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing the overall configuration of the device of the present invention, FIG. 2 is a cross-sectional view taken along line m-n in FIG. 1, and FIGS.
The figure is a partially enlarged sectional view of FIG. 1 showing the characteristic parts of the device of the present invention, FIG. 7 is a graph showing changes in the pressure generated in the pump chamber obtained in the device of the present invention, and FIGS. 8 and 9 are FIG. 2 is an enlarged sectional view of a main part of a conventional drive coupling device. 1...Differential gear device 2...Differential limiting section 11...
・First output shaft 12...Second output shaft 20...
Rotor body 22... Vane 24... Communication groove 30... Cam ring 31. 32... Side plate 40... Pump chamber 42... Suction hole 43.
...Suction check valve 44...Discharge hole 45...
・Communication hole 46...Discharge check valve T...Oil tank patent Applicant: Koyo Seiko Co., Ltd. Agent Patent attorney: Noboru Kono Discharge side funeral map

Claims (1)

[Claims] 1. A casing that rotates in conjunction with one of the front and rear wheels, and a rotor that is housed inside the casing and rotates in conjunction with the other. In a four-wheel drive drive coupling device that distributes driving force using hydraulic pressure as a medium, the hydraulic pressure is received on one side of the communication hole that is fitted in the middle of the communication hole that communicates the discharge side of the pump chamber with the low pressure part. A four-wheel drive drive coupling device comprising a sliding spool and opening/closing means for opening and closing the communication hole in accordance with the sliding spool.