JPH0735160A - Driving force transmission device - Google Patents

Abstract

PURPOSE:To reduce the power consumption in a driving coil and enhance the reliability of operation and manufacture a spool so favorably in terms of efficiency. CONSTITUTION:A second spring 67, making a second spool 63 return to the side of an opening end 61b of a spool chamber 61, is spread over in space between a spring supporting part 62a of a first spool 62 and a stepped part of the second spool 63. With this constitution, since energizing force of the second spring 67 can be damped in a state that the first spool 62 is slidden to the side of a blocking end 61a of the spool chamber 61, magnetic force for sliding the second spool 63 to the side of the blocking end 61a can be weakened. Therefore, the power consumption in a driving coil 69 can be reduced. Such a fact that the second spool is shifted together with the first spool by a spike current is preventable by the second spring 67. In addition, as the second spool is formable into a cylindrical form, this spool can be efficiently finished by means of through feed system polishing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes a hydraulic pressure generated by a hydraulic pump interposed between a pair of rotary shafts according to a difference in rotational speed between the rotary shafts to drive the drive force between the rotary shafts. The present invention relates to a driving force transmission device that transmits power.

[0002]

2. Description of the Related Art A four-wheel drive vehicle that travels by transmitting the driving force of an engine to both the front and rear wheels is not only excellent in running on bad roads, but also in terms of acceleration and running stability even on ordinary roads. Because it is excellent, it is rapidly becoming popular. In recent years, when a rotation speed difference occurs between the front and rear wheels, a drive force transmission device that changes the drive force distribution to both wheels according to the rotation speed difference is provided, and the four-wheel drive state is practically always maintained. The so-called full-time four-wheel drive vehicles that are made available are the mainstream. As one of such driving force transmission devices,
It is known to utilize the hydraulic pressure generated by a hydraulic pump interposed between the rear wheels. This is because a hydraulic pump (generally a vane pump) is configured by housing a rotor that is rotated in conjunction with a transmission shaft for one of the front and rear wheels and a rotor that is rotated in conjunction with a transmission shaft for the other. In the pump chamber formed between the rotor and the rotor, a hydraulic pressure is generated according to the rotational speed difference between the transmission shafts, and the driving force is transmitted between the front and rear wheels via this hydraulic pressure. The hydraulic pressure generated corresponding to the magnitude of the relative rotation, that is, the magnitude of the rotational speed difference between the front and rear wheels acts to suppress the relative rotation between the rotor and the casing. Therefore, the driving force corresponding to the rotational speed difference between the front and rear wheels is transmitted from one of the front and rear wheels to the other through this hydraulic pressure, and a so-called four-wheel drive state is realized.

Conventionally, as the above-mentioned driving force transmission device, a variable throttle is provided in the middle of the oil passage on the discharge side of the hydraulic pump for the purpose of obtaining an appropriate driving force transmission characteristic according to the traveling state, and a plurality of driving force transmission devices relating to the traveling state are provided. There is provided a device in which the aperture of the variable aperture is adjusted by a solenoid based on the combination of the state quantities (see JP-A-4-321432).
(See the official gazette). In this driving force transmission device, for example, it is possible to reduce the transmission torque in order to prevent the occurrence of the tight corner braking phenomenon when the vehicle turns at a low speed, and to obtain a high transmission torque when required. That is, there is an advantage that a plurality of torque transmission characteristics can be selected according to the traveling state.

FIG. 9 is a cross-sectional view of an essential part showing an example of a conventional driving force transmission device provided with the variable diaphragm. In this driving force transmission device, a holding cylinder 92 is interposed between a vane pump 90 that generates a hydraulic pressure according to a rotational speed difference between the front and rear wheels and an output shaft 91 that works with either one of the front and rear wheels. The first spool 94 and the second spool 95 are axially slidably inserted into the spool chamber 93 formed at the axial center of the holding cylinder 92. A drive coil 96 for moving each of the spools 94 and 95 to the closed end 93a side of the spool chamber 93 is provided on the outer side of the.

The spool chamber 93 has a first communication passage 97.
And the second communication passage 98, respectively, and communicates individually with the discharge side of the vane pump 90.
The open ends of the spool chambers 93 on the side of the spool chambers 93 are displaced by a predetermined distance in the axial direction. The second communication passage 98 is formed to have a smaller diameter than the first communication passage 97 so as to have a smaller flow rate. The energization of the drive coil 96 can be controlled in two steps, and magnetic fields having different strengths can be formed inside the spool chamber 93. Further, the first spool 94 is provided between the first spool 94 and the closed end 93 a of the spool chamber 93, and the opening end 93 b of the spool chamber 93 is provided between the first spool 94 and the closed end 93 a.
The first spring S1 for urging the second spool 95 is tightly arranged, and the second spool 95 is opened between the outer peripheral flange portion 95a of the second spool 95 and the holding cylinder 92 in the spool chamber 93. A second spring S2 for biasing the end 93b is tightly attached.

When the drive coil 96 is de-energized, the spools 94, 95 are moved toward the open end 93b of the spool chamber 93 by the biasing forces of the first spring S1 and the second spring S2. As a result, the first communication passage 97 is closed, and the second communication passage 98 having a small flow rate is opened. When the drive coil 96 forms a weak magnetic field, the first spool 94 is moved to the closed end 93a side of the spool chamber 93 against the biasing force of the first spring S1. The communication passage 98 is also closed. Further, when a strong magnetic field is formed, the second spool 95 is also moved to the closed end 93a side of the spool chamber 93, whereby the first communication passage 97 with a large flow rate is formed.
Is opened. By the above operation, the first communication passage 97 is closed and the second communication passage 98 is opened, the first communication passage 97 is opened and the second communication passage 98 is closed, and both It is possible to obtain a state in which both communication passages 97 and 98 are closed, and three different power transmission characteristics can be realized due to the difference in oil passage resistance in each state.

[0007]

According to the conventional driving force transmission device provided with the variable diaphragm, the spools 94, 95 are provided.
Is required to move to the closed end 93a side of the spool chamber 93, a magnetic field strength that can oppose the sum of the urging forces of the springs S1 and S2 is required. Therefore, there is a problem that the power consumption of the drive coil 96 is large. It was

Further, when only the first spool 94 is moved by the drive coil 96, the peak value of the spike current may momentarily exceed the current value required to move both spools 94 and 95. Yes, in this case,
There is a possibility that not only the first spool 94 but also the second spool 95 may be moved. Further, the collar portion 9 for locking the second spring S2 is provided on the outer circumference of the second spool 95.
Since it is necessary to project 5a, and the collar portion 95a is an obstacle, the outer periphery of the spool 95 cannot be polished by the through-feed method. For this reason, it is necessary to polish and finish by an inefficient plunge cut method, which causes a problem of high manufacturing cost.

On the other hand, the second spring S2 needs to be constructed with a very small number of turns of about 1.5 to 2 due to space constraints, and the winding diameter is large. However, the design conditions were very strict and it was difficult to obtain the desired spring constant. The present invention has been made in view of the above problems, and it is possible to reduce the power consumption of the drive coil, improve the reliability of the operation, and drive the spool efficiently. An object is to provide a force transmission device.

It is another object of the present invention to provide a driving force transmission device capable of easily obtaining a desired spring constant for a spring for urging a spool.

[0011]

A driving force transmission device of the present invention for achieving the above object is interposed between a first rotary shaft and a second rotary shaft, and has a rotational speed of both rotary shafts. It has a hydraulic pump that transmits the driving force between both rotary shafts via hydraulic pressure generated according to the difference, and a spool chamber that communicates with the discharge side of the hydraulic pump through a plurality of communication passages. Each communication passage is opened and closed by selectively moving the first spool and the second spool, which are arranged on one end side and the other end side inside the chamber, to one end side of the spool chamber by magnetic force. In a driving force transmission device including a variable throttle for controlling and adjusting oil passage resistance on the discharge side of a hydraulic pump, the variable throttle restricts the first spool moved to one end side of the spool chamber from the spool chamber. Of the spool chamber and the first spring that returns to the other end side of A second spring for returning the second spool moved to the end side to the other end side of the spool chamber, wherein the first spring is a predetermined part of the first spool and one end of the spool chamber. It is tight between the section and the second
The spring of (1) is tightened between a predetermined portion of the first spool and a predetermined portion of the second spool.

However, it is preferable that at least a part of the second spring is arranged in the internal space of the first spool.

[0013]

According to the driving force transmission device having the above structure, when the first spool is moved to the one end side of the spool chamber by the magnetic force against the biasing force of the first spring, the first spool and the first spool are moved. The urging force of the second spring tightly attached to the second spool can be damped in accordance with the movement amount of the first spool. Therefore, the magnetic force for moving the second spool to the one end side of the spool chamber can be weakened,
The supply current to the solenoid can be reduced.

Further, the second spring is provided with the first spool and the second spool.
Since it acts so as to separate from the spool of
When moving the first spool, it is possible to prevent the second spool from being simultaneously moved by the spike current. Further, the second spring is connected to the first spool and the second
Since it is interposed between the first spool and the second spool, it is not necessary to project a collar portion for locking the second spring on the outer circumference of the second spool. Therefore, the outer circumference of the second spool can be efficiently polished and finished by the through-feed method.

Particularly, when at least a part of the second spring is arranged in the internal space of the first spool, the winding diameter can be reduced and the total length of the second spring can be increased. It is possible to secure the degree of freedom in designing the spring, for example, the winding diameter can be arbitrarily selected to some extent.

[0016]

Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments. FIG. 1 is a sectional view showing a driving force transmission device for a four-wheel drive vehicle as an embodiment of the present invention. This driving force transmission device includes an input shaft 1 as a first rotary shaft that rotates in conjunction with one of the front and rear wheels and an output shaft 2 as a second rotary shaft that rotates in conjunction with the other of the front and rear wheels. A vane pump 3 as a hydraulic pump that generates a hydraulic pressure according to a rotational speed difference between the shafts 1 and 2 is provided, and a driving force is transmitted from the input shaft 1 to the output shaft 2 via the generated hydraulic pressure of the vane pump 3. Is.

Cylindrical rotor 30 of the vane pump 3
The storage grooves 30c having a predetermined depth extending in the radial direction are formed at equal intervals along the circumferential direction, and the rectangular flat plate-shaped vanes 30a are respectively stored in the storage grooves 30c so as to be movable in the radial direction. It has a known configuration. Between the vanes 30a and the bottoms of the storage grooves 30c, the vanes 30a are provided.
A compression coil spring 30b for urging the radial direction outward is interposed.

The casing of the vane pump 3 includes the rotor 3
In addition to containing 0, a pair of annular side plates 3
It is provided with a cam ring 31 sandwiched by 2, 33 and forming a plurality of pump chambers with the rotor 30, the side plates 32, 33, and a pressing plate 34, which penetrate in the thickness direction. Are integrally rotatably connected by a plurality of fixing bolts 35 screwed to the side plate 32.

Inside the cam ring 31, there is formed a hollow portion surrounded by both side plates 32 and 33, and the rotor 30 is housed in the hollow portion. The rotor shaft 4, which is the rotation shaft of the rotor 30, has the side plate 3 in the hollow portion of the side plates 32 and 33.
The cam ring 31 is inserted from the side 3 as shown.
Are supported on both sides by ball bearings. The rotor 30 is spline-coupled to the rotor shaft 4 between these bearing positions, and the vanes 30 are rotated as the rotor shaft 4 rotates.
The tip of a rotates while pressing the inner periphery of the cam ring 31. Further, the cross-sectional shape of the cam ring 31 as viewed from the side of the inner circumference is a shape in which recesses are formed at a plurality of positions on the circumferential surface,
A portion surrounded by these recesses and the outer circumference of the rotor 30 is configured as a pump chamber.

The input shaft 1 is spline-coupled to the end of the rotor shaft 4 protruding toward the side plate 33, and the output shaft 2 is outside the side plate 32 via a flange 21 formed at one end. It is connected to the side. As a result, the rotor 30 is interlocked with the rotation of the input shaft 1, and the casing having the side plate 33 as a part thereof is interlocked with the rotation of the output shaft 2.
Therefore, relative rotation occurs depending on the rotational speed difference between the input shaft 1 and the output shaft 2.

A thin cylinder 36 is fitted on the outside of the casing of the vane pump 3, and an annular oil tank T is formed between the cylinder 36 and the outer circumference of the casing. The oil of the vane pump 3 is sealed in the oil tank T. Then, each pump chamber of the vane pump 3 penetrates through the disc portions of the pressing plate 34 and the side plate 33 in the thickness direction, and a check valve V1 which allows only the inflow into the pump chamber is fitted in the middle thereof. The oil tank T is communicated with each of the different suction oil passages 40.

The side plate 32 has one end opened in each pump chamber, is folded inward in the radial direction, is connected to the bottom of the storage groove 30c of the vane 30a, and allows only the outflow from each pump chamber. A separate discharge oil passage 41 is formed by fitting the oil in the middle thereof. Further, the side plate 32 is formed with an oil guide hole 42 penetrating the side plate 32 in the thickness direction and a return hole 43 penetrating in the radial direction, and one end of the oil guide hole 42 is formed in the storage groove 30c. Side plate 32 to communicate with the bottom of
Is opened on the inner side surface of the side plate 32, and the other end is opened on the outer side surface of the side plate 32 so as to communicate with the annular groove 37 formed in the flange 21 of the output shaft 2. As a result, the bottom of the storage groove 30c communicates with the annular groove 37 via the oil guide hole 42. Further, the circulation hole 43 communicates the hollow portion of the side plate 32 with the oil tank T.

At one end of the output shaft 2 is formed a variable diaphragm 6 for changing the driving force transmission characteristic. In the variable throttle 6, a first spool 62 and a second spool 63 are slidably inserted into a spool chamber 61 formed at the end of the output shaft 2, and these spools 62,
The oil passage resistance on the discharge side of the vane pump 3 is adjusted by selectively moving 63 in the axial direction by a drive coil 69 fixed to the vehicle body side so as to face the outer circumference of the output shaft 2.

More specifically with reference to FIG. 2, the spool chamber 61 is formed concentrically with the axis of the output shaft 2, one end of which is closed and the other end of which is open.
The spool chamber 61 is in communication with the annular groove 37 via a first communication passage 64 and a second communication passage 65.
The ends of the communication passages 64 and 65 on the spool chamber 61 side are
The spool chambers 61 are opened in the inner periphery of the spool chamber 61 while being axially displaced from each other. In addition, the first communication passage 64 has the annular groove 3
The diameter is narrowed at the portion communicating with 7, and the flow rate is set to be smaller than that in the second communication passage 65.

As shown in FIG. 4, the first spool 62 has a cylindrical shape, and an annular spring receiving portion 62a is provided so as to project in the middle of the inner circumference thereof. Further, the second spool 63 has a stepped cylindrical shape, and the small diameter portion 63 a thereof is introduced into the first spool 62 with a predetermined gap. Then, the first spool 62 is
A first spring 66, which is a compression coil spring and is interposed in a gap between the second spool 63 and the second spool 63, and is tightly fitted between the spring receiving portion 62a and the closed end 61a of the spool chamber 61, allows the spool chamber to move. It is urged toward the open end 61b of 61. Further, the second spool 63 is arranged in series with the first spring 66, and is composed of a compression coil spring that is stretched between the stepped portion 63e of the second spool 63 and the spring receiving portion 62a. The second spring 67 biases the spool chamber 61 toward the open end 61b. The urging force of the first spring 66 is set to be sufficiently larger than the urging force of the second spring 67.

A retaining ring 68 is attached to the inner periphery of the spool chamber 61 near the opening end 61b, and the second spring 6 is attached.
The movement of the second spool 63 urged by 7 is restricted by the retaining ring 68. Further, the movement of the first spool 62 biased by the first spring 66 is regulated by contacting the stepped portion 63e of the second spool 63 locked by the stop ring 68.

Annular throttle grooves 62b and 63b are formed on the outer circumferences of the spools 62 and 63, respectively.
2b and 63b are provided with second spool 63 through through holes 62c and 63c penetrating the peripheral walls of spools 62 and 63, respectively.
Is communicated with the internal passage 63d. Further, an annular throttle groove 61c is formed in a portion of the inner periphery of the spool chamber 61 where the first communication passage 64 opens, and the throttle groove 61c is formed.
Are opened and closed according to the sliding of the first spool 62. Further, an annular throttle groove 61d is formed in a portion of the inner circumference of the spool chamber 61 where the second communication passage 65 is opened, and the throttle groove 61d corresponds to the sliding movement of the second spool 63. It is designed to open and close.

The annular groove 37 has an oil guide hole 42 and a vane 3.
It is communicated with each pump chamber of the vane pump 3 through the storage groove 30c of 0a and the discharge oil passage 41. Further, the internal space of each spool 62, 63 is communicated with the oil tank T via the hollow portion of the side plate 32 and the return hole 43. Therefore, both spools 62 and 63 are 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 in accordance with the above-mentioned sliding, the respective communication passages 64 and 65 are provided. Are opened and closed respectively, and the oil passage resistance on the discharge side of the vane pump 3 changes according to the opening and closing.

The sliding of the spools 62, 63 is performed by the action of a magnetic field formed by the drive coil 69 arranged so as to surround the output shaft 2. That is, each spool 62,
The whole or a part of 63 is formed of a magnetic material, and functions as a movable iron core of a solenoid by itself, and in accordance with energization of the drive coil 69, the spools 62, 63.
Slides in the direction of the closed end 61a of the spool chamber 61 to control opening / closing of the communication passages 64 and 65, respectively.

The drive coil 69 is selectively driven into a no-load state, a half-load state, and a full-load state depending on the presence or absence of an applied current and the magnitude of the applied current. In the no-load state, as shown in FIG. , 63 are moved to the opening end 61b side of the spool chamber 61 by the urging force of the springs 66, 67, whereby the throttle groove 61c is opened and the throttle groove 61d is closed. In this state, the pump chamber and the oil tank T are communicated with each other only through the first communication passage 64 having a small flow rate, and the N characteristic shown in FIG. 3, which is an intermediate transmission characteristic, is obtained. Further, in the half-loaded state, as shown in FIG.
Only the spool 62 slides to the closed end 61a side of the spool chamber 61, the throttle groove 61c is closed, and the communication between the pump chamber and the oil tank T is blocked. As a result, the P characteristic shown in FIG. 3, which is the highest transmission characteristic, is obtained. Further, in the fully loaded state, as shown in FIG. 7, both spools 62, 6
3 resists the urging force of the springs 66 and 67 and causes the closed end 61 to move.
Sliding to the a side, the throttle groove 61d is opened. In this state, the pump chamber and the oil tank T are communicated with each other through the second communication passage 65 having a large flow rate, and the S characteristic shown in FIG. 3, which is the lowest transmission characteristic, is obtained.

The transfer characteristic is changed according to a preset control map. For example, when the vehicle speed detected by the vehicle speed sensor is a predetermined value (for example, 10 km / h) or less and the steering angle detected by the steering angle sensor is large, the drive coil 69 is driven to select the S characteristic. This allows
The front and rear wheels are loosely connected, and the difference in rotational speed between the two wheels due to the difference in the turning trajectories of the front and rear wheels can be absorbed without difficulty.
Surely prevent the occurrence of tight corner braking phenomenon. On the other hand, when the accelerator opening sensor detects that the accelerator opening is in a substantially fully open state even though the speed detected by the vehicle speed sensor is zero (this is a so-called stuck state), the P characteristic Select and connect the front and rear wheels almost directly to allow escape from the stack.

According to the above embodiment, since the second spring 67 is tightly attached between the spring receiving portion 62a of the first spool 62 and the stepped portion 63e of the second spool 63, the first spring 67 is tightened. When the spool 62 is slid to the closed end 61a side of the spool chamber 61, the second spring 67 extends by the amount corresponding to this sliding amount and the biasing force is attenuated. For this reason,
The magnetic field strength for moving the second spool 63 to the closed end 61a side is small, and the drive coil 69 is accordingly reduced.
Power consumption can be reduced.

Further, since the second spring 67 acts so as to separate the first spool 62 and the second spool 63 from each other, the first spool 62 is moved to the spool chamber 6
It is possible to prevent the second spool 67 from being moved to the closed end 61a side together with the first spool 62 by the spike current when the first spool 62 is moved to the closed end 61a side. Therefore, the reliability of operation can be improved.

Further, since it is not necessary to project a collar portion for locking one end of the second spring 67 on the outer circumference of the second spool 63, the outer circumference of the second spool 63 is formed by the through feed method. The polishing finish can be done efficiently. Moreover, since the second spring 67 is arranged on the inner circumference of the first spool 62, it is possible to lengthen the entire length thereof and arbitrarily select the number of windings, and the winding diameter is small. As a result, the degree of freedom in designing the second spring 67 is increased, so that a desired spring constant can be easily obtained.

The driving force transmission device of the present invention is not limited to the above embodiment, but may be the second spring 67, for example.
Of the first spring 66 and the holes 62h and 6 formed in the closed end 61a of the first spool 62 and the spool chamber 61.
Various design changes such as arranging within 1h (see FIG. 8 for both) can be made.

[0036]

As described above, according to the driving force transmission device of the present invention, the second spring for urging the second spool is
Since the first spool and the second spool are tightly attached to each other, when the first spool is slid to the one end side of the spool chamber by the drive coil, the second spool corresponding to this sliding amount is generated. The biasing force of the spring can be attenuated. Therefore, the magnetic force for sliding the second spool can be weakened, and the power consumption of the drive coil can be reduced.

Further, since the second spring acts so as to separate the first spool and the second spool from each other,
When moving the first spool by the drive coil,
It is possible to prevent the second spool from being moved together with the first spool due to the spike current, and it is possible to improve the reliability of operation. Further, since it is not necessary to project a collar portion for locking one end of the second spring on the outer circumference of the second spool, the outer circumference of the second spool can be finished by through-feed polishing. The second spool can be manufactured efficiently and at low cost.

In particular, according to the driving force transmission device of the second aspect, since at least a part of the second spring is arranged in the internal space of the first spool, the total length and the number of turns can be set to some extent. It is possible to easily and surely obtain a desired spring constant as a result of being able to secure the degree of freedom in designing the second spring, such as by selecting the above or by reducing the winding diameter. Produce the effect of.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a driving force transmission device for a four-wheel drive vehicle showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the driving force transmission device.

FIG. 3 is a graph showing driving force transmission characteristics.

FIG. 4 is an enlarged cross-sectional view showing details of a spool, (a)
Shows the first spool, and (b) shows the second spool.

FIG. 5 is an enlarged cross-sectional view of a main part showing a state of a spool under no load.

FIG. 6 is an enlarged cross-sectional view of essential parts showing a state of a spool under a half load.

FIG. 7 is an enlarged cross-sectional view of essential parts showing a state of a spool at full load.

FIG. 8 is a cross-sectional view of essential parts showing another embodiment of the present invention.

FIG. 9 is a cross-sectional view of a main part showing a conventional example.

[Explanation of symbols]

 1 Input Shaft (First Rotation Shaft) 2 Output Shaft (Second Rotation Shaft) 3 Vane Pump (Hydraulic Pump) 6 Variable Throttle 61 Spool Chamber 62 First Spool 63 Second Spool 64,65 Communication Passage 66 First Spring 67 Second spring

Claims (2)

[Claims] Claim: What is claimed is: 1. A driving force is transmitted between both rotary shafts through a hydraulic pressure that is interposed between the first rotary shaft and the second rotary shaft and that is generated according to a difference in rotational speed between the rotary shafts. A first spool having a hydraulic pump for performing and a spool chamber that communicates with a discharge side of the hydraulic pump via a plurality of communication passages, the first spool being disposed on one end side and the other end side inside the spool chamber. By selectively moving the second spool and the second spool to one end side of the spool chamber by magnetic force, opening and closing of each communication passage is controlled, and a variable throttle that adjusts oil passage resistance on the discharge side of the hydraulic pump is provided. In the driving force transmission device, the variable throttle restricts the first spool moved to the one end side of the spool chamber to the other end side of the spool chamber, and the one end side of the spool chamber. The second spool that was moved to the other end of the spool chamber. And a second spring, wherein the first spring is tightened between a predetermined portion of the first spool and one end of the spool chamber, and the second spring is attached to the first spool. A driving force transmission device characterized in that it is tightly fitted between a predetermined portion and a predetermined portion of the second spool. 2. At least a part of the second spring is provided with a first
The drive force transmission device according to claim 1, wherein the drive force transmission device is arranged in the internal space of the spool.