JPH04366035A - Drive connecting device for four-wheel drive - Google Patents

Abstract

PURPOSE:To provide stably a plurality of transmission properties corresponding to respective shift positions of a throttle spool by providing a means for locating the throttle spool shifting in a rotatable casing of a hydraulic pump for generating oil pressure corresponding to a difference between the rotational speed of front and rear wheels in a plurality of shift positions. CONSTITUTION:A drive connecting device for four-wheel drive consitutes a hydraulic pump (vane pump) 3 for generating oil pressure corresponding to a difference between the rotational speed of both front and rear wheels between an input shaft rotatably interlocked with one of front and rear wheels and an output shaft rottably interlocked with the other of both wheels to transmit a driving force from the input shaft to the output shaft 2 through the generated oil pressure. Also, a pressure plate 32 in the pump 3 is connected through a connecting member 5 to the output shaft 2 and here a throttle spool 6 for adjusting the passage resistance of discharged oil is built in. Then, a movable tube 7 connected to the outer end of the throttle spool 6 is provided outside the movable tube 7 with electromagnets 8a, 8b having magnetic poles opposed staggered to a plurality of inducing teeth 70 on outer periphery of the movable tube 7 to function as a locating means.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention realizes a four-wheel drive state using hydraulic pressure generated in a hydraulic pump interposed between the front and rear wheels according to the difference in rotational speed between the two wheels. The present invention relates to a drive coupling device for wheel drive.

0002

[Prior Art] Four-wheel drive vehicles, which drive by transmitting engine driving force to both the front and rear wheels, can achieve stable driving regardless of natural conditions such as weather and road surface conditions, and regardless of driving conditions. It is attracting attention as a thing. In recent years, drive coupling devices have been installed that automatically change the distribution of drive power between the front and rear wheels according to the difference in rotational speed between the front and rear wheels, making it possible to virtually always have four-wheel drive. Full-time four-wheel drive vehicles have become mainstream, and one known drive coupling device of this type utilizes the hydraulic pressure generated by a hydraulic pump interposed between the front and rear wheels.

[0003] A hydraulic pump (generally a vane pump) is constructed by coaxially combining a rotor and a casing that are individually interlocked and connected to the transmission shafts for the front and rear wheels. In between, a relative rotation corresponding to the rotational speed difference between the two transmission shafts, that is, the rotational speed difference between the front and rear wheels is generated. With this configuration, hydraulic pressure corresponding to the magnitude of the relative rotation, that is, the magnitude of the difference in rotational speed between the front and rear wheels, is generated in the pump chamber formed between the rotor and the casing, and the relative rotation between the rotor and the casing is generated. This hydraulic pressure, which acts to suppress rotation, allows driving force to be transmitted from one of the front and rear wheels to the other, thereby realizing a four-wheel drive state.

Now, the transmission characteristics required for a four-wheel drive vehicle vary depending on the driving condition. For example, during cornering, in order to prevent the occurrence of tight corner braking, the transmission characteristics required for a four-wheel drive vehicle differ as much as possible between the front and rear wheels. It is desirable to have a connection that is as loose as possible, and it is desirable to have a connection that is as rigid as possible to improve driving stability when driving straight at high speed. desirable. In the above-mentioned drive coupling device that utilizes the hydraulic pressure generated by a hydraulic pump, the transmission characteristics can be changed by changing the pressure characteristics of the hydraulic pump, and this pressure characteristic depends on the magnitude of the oil flow resistance on the discharge side of the hydraulic pump. Dependent. Therefore, a variable throttle is configured on the discharge side of the hydraulic pump, and the throttle opening is determined based on the detection results of various state quantities related to the driving condition, such as the steering angle, vehicle speed, engine speed, etc. By changing the oil flow resistance on the discharge side, it is possible to obtain transmission characteristics that suit the driving conditions.

[0005] However, in the hydraulic pump, not only the rotor but also the casing rotates, and therefore, a structural contrivance is required to construct a variable throttle whose opening degree can be adjusted from the outside. A drive coupling device disclosed in Japanese Patent Application Laid-Open No. 2-106438 is a typical device that solves this problem. FIG. 7 is a longitudinal sectional view showing the configuration of the main parts of this drive coupling device.

As shown in the figure, this drive coupling device connects the casing of a hydraulic pump 3 that generates hydraulic pressure according to the difference in rotational speed between the front and rear wheels and the corresponding transmission shaft 2, with a cylindrical portion 50 in the middle. The aperture spool 6 is coaxially connected via a connecting member 5 having The coil spring 60a interposed between the coil spring 60a and the bottom of the spool chamber 60 biases the drive coil 9 toward the connection side with the casing, while the drive coil 9, which is restrained in a non-rotating state outside the cylindrical portion 50, is It has a set configuration.

The aperture spool 6 is driven by a solenoid having itself as an iron core due to the action of a magnetic field generated in the spool chamber 60 in response to energization of the drive coil 9, and resists the spring force of the coil spring 60a. The opening end of the communication hole 50a, which communicates with the discharge side of the hydraulic pump 3 via the oil guide hole 42 and the annular groove 43, opens and closes. Therefore, based on the detection result of the running state, the drive coil 9
By controlling the energizing current and changing the sliding position of the throttle spool 6, the opening area of the communication hole 50a is changed, and the oil flow resistance on the discharge side of the hydraulic pump 3 is changed, resulting in a transmission that adapts to the running condition. characteristics are obtained.

[0008]

[Problems to be Solved by the Invention] However, in this configuration, as shown in the figure, there is a position in which the retaining ring 60b is engaged with the open end of the spool chamber 60, and a position in which it is in contact with the innermost end of the spool chamber 60. The aperture spool 6 between these two positions is reliably positioned.
is in a floating state with one side supported by the coil spring 60a, so the spool chamber 60 passes through the communication hole 50a.
There is a risk that the sliding position of the throttle spool 6 may fluctuate due to the action of external forces other than the magnetic field formed by the drive coil 9, such as the flow of hydraulic oil flowing into the drive coil 9. There is a problem in that a stable correspondence relationship cannot be obtained with the moving position, and it is difficult to achieve highly reliable transmission characteristics that match the driving conditions.

Furthermore, since the throttle spool 6 itself is magnetized when the drive coil 9 is energized, magnetic powder such as iron powder contained in the hydraulic oil adheres to the throttle spool 6, and this adhered powder blocks the oil passage. There is a risk that the flow of hydraulic oil may be obstructed, and
There is a possibility that this adhered powder may enter the sliding portion between the cylinder chamber 60 and the sliding movement of the throttle spool 6, and in either case, the drive coupling device cannot operate normally.

The present invention has been made in view of the above circumstances, and it is possible to improve oil flow on the discharge side by moving within a rotating casing of a hydraulic pump that generates hydraulic pressure according to the difference in rotational speed between the front and rear wheels. We have proposed a new means of reliably positioning the aperture spool that changes the resistance at multiple movement positions, and created a four-wheel drive drive coupling device that can stably realize multiple transmission characteristics corresponding to each movement position. The purpose is to provide.

[0011]

[Means for Solving the Problems] A four-wheel drive drive coupling device according to the present invention includes a rotor and a casing that are individually interlocked and connected to transmission shafts for front and rear wheels and rotate relative to each other on the same axis. A spool chamber communicating with the discharge side of the hydraulic pump is formed in the axial center of a connecting member that constitutes the hydraulic pump and coaxially connects the rotor or casing with the corresponding transmission shaft, and the spool chamber is housed in the spool chamber. For four-wheel drive, the oil flow resistance on the discharge side of the hydraulic pump is adjusted by moving a throttle spool to change the transmission characteristics to the two transmission shafts using the hydraulic pressure generated inside the hydraulic pump as a medium. In the drive coupling device, a plurality of screws are fitted on the outside of the coupling member so as to be slidable in the axial direction, a part of which is coupled to the aperture spool, and arranged at a predetermined pitch in the axial direction. A movable cylinder having guide teeth on its outer periphery, which are arranged side by side in the axial direction facing the outside of the movable cylinder, and the opposing relationship between each magnetic pole and the guide teeth is shifted by approximately half of the pitch. It is characterized by comprising a certain plurality of electromagnets.

0012

[Operation] In the present invention, the driving means for the throttle spool, which is slidably housed in the spool chamber inside the connecting member that coaxially connects the rotor or casing and the corresponding transmission shaft, is slid to the outside of the connecting member. It consists of a movable cylinder that can be freely inserted and a plurality of electromagnets arranged in parallel in the axial direction facing the outside of the cylinder, and the magnetic pole and induction tooth of each electromagnet are changed according to the switching between excitation and demagnetization of each electromagnet. The aperture spool is moved via the moving cylinder by the magnetic attraction force generated during this time.

First, when a suitable one of the plurality of electromagnets is energized, among the plurality of induction teeth on the outside of the movable cylinder, those close to the magnetic pole of the electromagnet are attracted, and this induction tooth and the magnetic pole are aligned with the axis. The moving tube is moved until it is in a longitudinally aligned position. At this time, the magnetic poles of the electromagnets adjacent to the electromagnets face the guide teeth on the outside of the movable cylinder at a position shifted by approximately half of the formation pitch of the teeth, and when both electromagnets are excited in this state, both A magnetic attraction force is generated between each of the magnetic poles and the guiding teeth, and the movable cylinder moves until the positional relationship in the axial direction between both magnetic poles and the guiding teeth adjacent to each one is the same. Furthermore, at this time, when the previously excited electromagnet is demagnetized, the movable cylinder moves until it reaches a position where the magnetic pole of the subsequently excited electromagnet and the induction teeth that have been attracted to it are aligned in the axial direction. By repeating this, the movable cylinder and the aperture spool connected thereto move as one unit by a length of 1/4 of the formation pitch of the guide teeth, and at each movement position, the magnetic pole of the electromagnet and the guide on the outside of the movable cylinder move. Reliably restrained by magnetic attraction between teeth.

[0014]

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

The device of the present invention has an input shaft 1 that rotates in conjunction with one of the front and rear wheels, and an output shaft 2 that rotates in conjunction with the other.
A vane pump 3 is configured, which is a hydraulic pump that generates oil pressure according to the rotational speed difference between the two shafts 1 and 2, that is, the rotational speed difference that occurs between the front and rear wheels. 1 to the output shaft 2.

The rotor 30 of the vane pump 3 includes a plurality of rectangular flat plate vanes 30a, 30a, which can move forward and backward in the radial direction, and each of these vanes 30a, 30a, is attached outward by a separate coil spring 30b. The casing of the vane pump 3 includes a cam ring 31 which is a cylindrical member with uneven thickness and has approximately the same length as the rotor 30.
and a pressure plate 32 in the shape of a thick hollow disc.
and a side plate 33 and a presser plate 34, both of which have a shape in which short cylinders are coaxially connected to the inner circumferential side of a hollow disc.
The cylindrical portion of the presser plate 34 is externally fitted onto the cylindrical portion of the side plate 33 to integrate the two coaxially, and these and the pressure plate 32 are positioned coaxially on both sides of the cam ring 31. , all of these are integrally connected by a plurality of fixing bolts 35, 35, . The structure is as follows.

The rotor shaft 4, which is the rotation axis of the rotor 30, is
Cylindrical portion of side plate 33 and pressure plate 3
2 from the side plate 33 side, and is supported by a ball bearing on the pressure plate 32 side and a needle roller bearing on the side plate 33 side on both sides of the cam ring 31 as shown.

The rotor 30 is sandwiched on both sides by a pressure plate 32 and a side plate 33, and is housed in a cavity formed inside the cam ring 31, and is spline-coupled to the rotor shaft 4 between the aforementioned supporting positions. can be,
It is configured to rotate coaxially with the rotation of the rotor shaft 4 inside the cam ring 31. The inner periphery of the cam ring 31 has an axial cross-sectional shape with a plurality of recesses formed around a circular periphery, and the rotor 30 is located at the positions where these recesses are formed.
A plurality of chambers are formed surrounded by the outer periphery of the rotor 30 and the cam ring 31, and these chambers function as pump chambers that generate hydraulic pressure in response to relative rotation that occurs between the rotor 30 and the cam ring 31 as described below.

The input shaft 1 is coaxially flange-coupled to the protruding end of the rotor shaft 4 toward the side plate 33, and the output shaft 2 is connected via a connecting member 5 configured as described below. It is coaxially coupled to the outer surface of the pressure plate 32. As a result, the rotor 30 rotates in conjunction with the rotation of the input shaft 1, and the casing, of which the pressure plate 33 is a part, rotates in conjunction with the rotation of the output shaft 2, so that there is a gap between the rotor 30 and the casing. is input shaft 1
A relative rotation occurs that corresponds to the rotational speed difference between the front wheels and the output shaft 2, that is, the rotational speed difference between the front and rear wheels.

A thin-walled cylindrical tank member 36 is fitted on the outside of the casing, and the hydraulic oil for the vane pump 3 is supplied to the oil formed in an annular shape between the tank member 36 and the outer periphery of the casing. It is sealed inside the tank T. Each of the plurality of pump chambers inside the cam ring 31 is connected to a presser plate 3.
Separate suction oil passages 40, 40... (1 (only the book is shown) communicates with the oil tank T.

On the other hand, the pressure plate 32 has one end opened in each of the plurality of pump chambers, and is bent radially inward to form vanes 30a on the inner peripheral side of the rotor 30.
Separate discharge oil passages 41, 41 (only one shown) are formed in communication with the base of the oil pumps 30a, and are fitted with check valves that allow only outflow from each pump chamber. . Further, an annular groove 43 is provided on the outer inner periphery of the hollow portion of the pressure plate 32, and this annular groove connects to the bases of the vanes 30a, 30a, which are communicated with the respective pump chambers by the discharge oil passages 41, 41,... 43 is communicated with the pressure plate 32 through an oil guide hole 42 passing through the pressure plate 32 in the thickness direction. Further, the hollow portion of the pressure plate 32 is communicated with the oil tank T on the outside of the casing through a return hole 44 passing through the pressure plate 32 in the radial direction.

FIG. 2 is an enlarged sectional view of a characteristic portion of the device of the present invention. A connecting member 5 that is interposed between the pressure plate 32 and the output shaft 2 and connects them includes a thick-walled cylindrical aperture housing 51 that has a connecting flange with the pressure plate 32 on one side, and an output shaft. The aperture housing 5 is provided with a flange member 52 that is coupled to a connecting flange 2a formed at the shaft end of the diaphragm housing 5.
The two are coaxially integrated by a plurality of fixing bolts 53, 53, . . . screwed into the peripheral wall of one.

The inner cavity of the throttle housing 51 has a circular cross section and forms a spool chamber 60 that communicates with the hollow portion of the pressure plate 32.
0, a throttle spool 6 is fitted inside so as to be slidable in the axial direction.

An annular throttle groove 61 is formed on the inner periphery of the spool chamber 60, and this throttle groove 61 connects to a communication hole formed in the throttle housing 51 by fixing the throttle housing 51 to the pressure plate 32. It communicates with the annular groove 43 on the outer surface of the pressure plate 32 via the groove 51a. Further, an annular throttle groove 62 is formed on the outer periphery of the throttle spool 6, and this throttle groove 62 has an opening on the pressure plate 32 side and is an oil passage hole formed in the axial center of the throttle spool 6. It is connected to 63.

The annular groove 43 communicating with the throttle groove 61 on the inner periphery of the spool chamber 60 is connected to the discharge of each pump chamber of the vane pump 3 via the oil guide hole 42 and the separate discharge oil passages 41, 41, . . . as described above. The oil passage hole 63 that communicates with the throttle groove 62 on the outer periphery of the throttle spool 6 is connected to the oil tank T through the hollow part of the pressure plate 32 and the reflux hole 44.
is connected to.

Therefore, the throttle spool 6 is connected to the vane pump 3.
It is arranged in the middle of the discharge side oil passage that communicates the discharge side of each pump chamber with the oil tank T, and the communication area between the throttle groove 61 and the throttle groove 62 is reduced by movement within the spool chamber 60. It functions as a variable throttle that adjusts the oil flow resistance on the discharge side of the vane pump 3. Note that the communication area between the throttle grooves 61 and 62 is the pressure plate 3 of the spool chamber 60.
When the aperture spool 6 is in contact with the retaining ring 60b, the aperture spool 6 is at its maximum, and the aperture spool 6 is generated from this position toward the flange member 52.
The oil passage resistance on the discharge side of the vane pump 3 conversely increases as the communication area decreases.

The device of the present invention is characterized by the structure of the drive means for moving the aperture spool 6. This driving means includes a cylindrical movable cylinder 7 that is fitted onto the outer periphery of the aperture housing 51 so as to be slidable in the axial direction, and a cylindrical moving cylinder 7 that is arranged side by side in the axial direction so as to face the outside of the movable cylinder 7. The motor is constructed of a pair of electromagnets 8a and 8b, and serves as a reluctance step motor that performs linear motion.

The electromagnets 8a and 8b are fixedly installed inside a cylindrical support tube 80 surrounding the outside of the connecting member 5, and are supported in the axial direction by a spacer 81 made of a non-magnetic material interposed between the two. They are spaced apart by a predetermined length, and together with the support cylinder 80, are restrained in a non-rotational state by a part of the vehicle body via a connecting member 82 made of a highly elastic material such as hard rubber. The support cylinder 80 also coaxially rotatably supports the connecting member 5 via a bearing metal 83 and a ball bearing 84 fitted to the inner periphery of both ends thereof. The electromagnets 8a and 8b are arranged to face the movable cylinder 7 in close proximity without changing their radial positions.

A plurality of guiding teeth 70, 70, .
The distance between the electromagnets 8a and 8b formed by the spacer 81 is such that the magnetic pole protruding from the inner circumferential side of one of the electromagnets 8a is attached to one of the induction teeth 70, as shown in the figure. When aligned, the magnetic poles similarly protruding from the inner peripheral side of the other electromagnet 8b are positioned between adjacent induction teeth 70, 70, that is, the magnetic poles of the electromagnets 8a, 8b and the induction teeth 70, These guiding teeth 70 are opposed to 70...
, 70 . . . are set to be shifted by approximately half the pitch A of formation.

The movable cylinder 7 has a connecting plate 71 extending radially inward through a gap formed by cutting out a portion of the contact surface of the flange member 52 with the aperture housing 51. The tip of the connecting plate 71 is connected to the end of the aperture spool 6 on the flange member 52 side via a fixing bolt 72. Therefore, the throttle spool 6 moves in accordance with the sliding movement of the movable cylinder 7 that occurs in the axial direction with respect to the connecting member 5, and as described above, this movement changes the oil flow resistance on the discharge side of the vane pump 3.

FIGS. 3 to 5 are explanatory diagrams of the operation of the driving means constructed as described above. FIG. 3 shows a case where only the electromagnet 8a is in an excited state, and at this time, a magnetic attraction force is generated between the magnetic pole of the electromagnet 8a and the induction tooth 70 that faces the electromagnet 8a, and the movable cylinder 7 , the magnetic pole of the electromagnet 8a and the guiding tooth 70 are moved to a position where they are aligned in the axial direction.

FIG. 4 shows a case where both the electromagnets 8a and 8b are in an excited state, and at this time, magnetic attractive force to the magnetic poles of the electromagnets 8a and 8b acts on the induction teeth 70 on the outside of the movable cylinder 7, respectively. Therefore, the movable cylinder 7 moves to a position where both magnetic attraction forces are balanced, that is, a position where the positional relationship in the axial direction between the guiding teeth 70 and both magnetic poles is the same.

FIG. 5 shows a case where only the electromagnet 8b is in an excited state. When the transition from FIG. 4 to FIG. 5 occurs, that is, when the electromagnet 8a is demagnetized, the magnetic attraction force between the magnetic pole of the electromagnet 8a and the induction teeth 70 disappears, and as a result, the movable cylinder 7
The magnetic pole of the electromagnet 8b and the guiding tooth 70 are moved to a position where they are aligned in the axial direction.

As described above, the movable tube 7 is equipped with electromagnets 8a and 8b.
5 from the position shown in FIG. 3 by switching between excitation and demagnetization.
Due to the movement of the throttle spool 6 in conjunction with the movable cylinder 7, the discharge side of the vane pump 3 is in the fully open state shown in FIG. 3, the intermediate state shown in FIG.
Three different aperture opening degrees in the fully closed state shown in FIG. 5 are obtained. Furthermore, the movable tube 7 at each moving position is moved by electromagnets 8a and 8.
The positioning is ensured by the magnetic attraction force generated between the position and the position b, and there is no possibility that the position will fluctuate.

As is clear from the figure, the moving distance between each moving position is 1/1 of the forming pitch A of the guide teeth 70, 70...
4, and by forming a large number of guiding teeth 70, 70... at a fine pitch on the outside of the movable cylinder 7, the moving length (unit stroke) of the movable cylinder 7 and the aperture spool 6 between each movement position can be reduced. In addition, the electromagnets 8a,
By arranging a larger number of electromagnets having the same positional relationship as that between 8b, it is possible to realize the three or more moving positions. Therefore, by combining these two, the throttle spool 6 can be moved in multiple stages with a small unit stroke, and the oil flow resistance on the discharge side of the vane pump 3 can be finely adjusted.

In the device of the present invention constructed as described above, when a rotational speed difference occurs between the input shaft 1 and the output shaft 2, the relative rotation at a speed corresponding to this rotational speed difference causes the rotor of the vane pump 3 to rotate at a speed corresponding to this rotational speed difference. Occurs between 30 and cam ring 31,
The hydraulic oil in the oil tank T is introduced into each pump chamber through a suction oil passage 40 that opens upstream in the direction of relative rotation, and is sealed between two adjacent vanes 30a, 30a. The pump is rotated together with the rotor 30 and pressurized, and a hydraulic pressure corresponding to the relative rotation speed, that is, the rotation speed difference between the input shaft 1 and the output shaft 2, is generated in each pump chamber. This oil pressure acts between the rotor 30 and the cam ring 31 to suppress their relative rotation, and causes the rotation from the input shaft 1 to the output shaft 2.
That is, a driving force corresponding to the difference in rotational speed between the front and rear wheels is transmitted from one of the front and rear wheels to the other through the connecting member 5,
A wheel drive condition is achieved.

The oil pressurized in each pump chamber passes through the discharge oil passage 41 that opens downstream in the relative rotation direction, and then reaches the vane 3.
0a, 30a..., each vane 30a,
30a..., after which the oil guide hole 42, the annular groove 43, and the communication hole 51a pass through the throttle groove 6.
1, passes through a communication portion having an area corresponding to the moving position of the aperture spool 6, and flows into the aperture groove 62;
Furthermore, the oil flows back to the oil tank T through the oil passage hole 63, the hollow part of the pressure plate 32, and the return hole 44. Note that this recirculated oil is sucked into each pump chamber of the vane pump 3 again and used for circulation.

In the above-described operation, the hydraulic pressure generated in each pump chamber is generated against the oil passage resistance during circulation of the hydraulic oil, mainly against the oil passage resistance on the discharge side, and the generated hydraulic pressure in response to changes in the rotational speed difference. The rate of change increases as the oil flow resistance increases, while the oil flow resistance on the discharge side of the vane pump 3 changes as described above in accordance with the movement of the throttle spool 6. is caused by switching between excitation and demagnetization of the electromagnets 8a and 8b.

FIG. 6 is a graph showing an example of the transmission characteristics achieved by the device of the present invention, in which the horizontal axis represents the rotational speed difference between the front and rear wheels, and the vertical axis represents the torque transmitted to the output shaft 2. be. The S characteristic shown by the broken line in the figure is the characteristic when the throttle spool 6 is in the moving position shown in FIG. , the characteristic when the throttle spool 6 is in the moving position shown in FIG. 5 due to the excitation of the electromagnet 8b and the oil flow resistance on the discharge side is maximum, and the N characteristic shown by the dashed line is the characteristic when the electromagnet 8a, 8
(b) shows the characteristics when the throttle spool 6 is in the moving position shown in FIG. 4 due to the excitation of both, and intermediate oil flow resistance is generated on the discharge side.

[0040] When a P characteristic is obtained in which the rate of increase in transmitted torque is large with respect to an increase in rotational speed difference, the input shaft 1 and the output shaft 2 are almost directly connected, and a slight slip occurring in one of the front and rear wheels is Accordingly, a large driving force is transmitted to the other vehicle, allowing stable driving on slippery surfaces such as snowy roads and gravel roads. In addition, if the S characteristic in which the increase rate of the transmitted torque with respect to the increase in rotational speed difference is small is obtained, the input shaft 1
A loose connection state is obtained between the front and output shafts 2, and the difference in rotational speed between the front and rear wheels, which occurs due to the difference in the turning trajectory between the front and rear wheels when turning at low speeds, is easily absorbed, resulting in a tight connection. The occurrence of corner braking phenomenon can be suppressed. Furthermore, if the N characteristic, which is an intermediate characteristic between the P characteristic and the S characteristic, is obtained, a gentle four-wheel drive state can be achieved, making it possible to drive comfortably and stably in general driving conditions. .

In the device of the present invention, various state quantities related to the running state, such as vehicle speed, acceleration/deceleration, amount of steering, etc., are detected by various sensors installed in various parts of the vehicle body, and based on the detection results, the electromagnet is activated. By turning off the excitation currents 8a and 8b and moving the throttle spool 6, the P characteristic, N characteristic, and S characteristic can be selectively realized, and comfortable driving can be achieved by realizing the transmission characteristic according to the driving condition. becomes possible.

At this time, the aperture spool 6 is accurately positioned at each moving position, and the position of the aperture spool 6 does not change after positioning.
Since it is not magnetized, there is no risk of problems such as obstructing the sliding of the throttle spool 6 or clogging the oil passage due to the adhesion of magnetic powder contained in the hydraulic oil, and each of the above characteristics can be obtained accurately and stably. .

In this embodiment, the vane pump 3
The casing and the output shaft 2 are connected via the connecting member 5, but the rotor shaft 4, which is the rotation axis of the rotor 30, is connected via the connecting member 5.
The present invention can also be applied to a configuration in which a connecting member 5 is interposed between the input shaft 1 and the connecting member 5, and the throttle spool 6 is arranged inside the connecting member 5.

[0044]

As described in detail above, in the device of the present invention, a movable cylinder having a plurality of guide teeth on the outer periphery is provided on the outside of the connecting member interposed between the rotor or the casing and the corresponding transmission shaft. A step motor is constructed by slidably inserting a plurality of electromagnets and arranging them in parallel in the axial direction so as to face the outside of the step motor, which performs linear motion. The connected throttle spools are moved by the magnetic attraction generated between the respective magnetic poles and the induction teeth in response to switching between excitation and demagnetization of each electromagnet, and the oil flow resistance on the discharge side of the hydraulic pump is adjusted. The positioning of the throttle spool at the moving position is performed reliably and accurately, and since the throttle spool is not magnetized, there is no risk of blocking the oil passage or hindering the sliding of the throttle spool due to adhesion of magnetic powder. The present invention has excellent effects such as stable transmission characteristics corresponding to each movement position of the throttle spool, and comfortable driving by realizing appropriate transmission characteristics depending on the driving condition.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing the overall configuration of the device of the present invention.

FIG. 2 is an enlarged sectional view of a drive means for the aperture spool, which is a characteristic part of the device of the present invention.

FIG. 3 is an explanatory diagram of the operation of the aperture spool driving means.

FIG. 4 is an explanatory diagram of the operation of the aperture spool driving means.

FIG. 5 is an explanatory diagram of the operation of the aperture spool driving means.

FIG. 6 is a graph showing an example of transmission characteristics realized by the device of the present invention.

FIG. 7 is an enlarged sectional view of a main part showing the configuration of a drive means for an aperture spool in a conventional drive coupling device.

[Explanation of symbols]

1 Input shaft 2 Output shaft 3 Vane pump 4 Rotor shaft 5 Connecting member 6 Aperture spool 7. Moving tube 8a Electromagnet 8b Electromagnet 30 Rotor 31 Cam ring 32 Pressure plate 33 Side plate 51 Aperture housing 52 Flange member 60 Spool room 70 Guide teeth

Claims (1)

[Claims] Claim 1: A hydraulic pump is constituted by a rotor and a casing that are individually interlocked and connected to transmission shafts for front and rear wheels and rotate relative to each other on the same axis, and a rotor or a casing and a corresponding transmission shaft. A spool chamber communicating with the discharge side of the hydraulic pump is formed in the shaft center of the connecting member coaxially connected, and the oil flow resistance on the discharge side of the hydraulic pump is adjusted by moving a throttle spool stored in the spool chamber. In the four-wheel drive drive coupling device, which changes the transmission characteristics to the two transmission shafts using the hydraulic pressure generated inside the hydraulic pump as a medium, the coupling member includes a sliding member on the outside of the coupling member in the axial direction. a movable tube that is movably fitted and connected to the aperture spool, and has a plurality of guide teeth arranged at a predetermined pitch in the axial direction on its outer periphery; and an outer side of the movable tube. A four-wheel drive vehicle characterized by comprising a plurality of electromagnets arranged in parallel in the axial direction facing the same, and in which the opposing relationship between each magnetic pole and the induction tooth is shifted by approximately half of the pitch. Drive coupling device.