JP2001032782A - Vane pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid mix of air into working fluid in a vane pump in a simple and compact structure. SOLUTION: This vane pump PR is provided with side plates 28R, 30 contained in an inner part of a casing 22, a cam ring 29R, and a rotor 32R, where a radial direction outer end of a vane 35 slidably engaged with a vane groove 321 of the rotor 32R is applied to an inner circumferential surface of the cam ring 29R. Inside a cylinder 142 axially penetrating a rotor shaft 14R supporting the rotor 32R, a piston 45R is slidably engaged. As temperature rises to let hydraulic fluid inside the casing 22 expand, the piston 45R moves right to absorb expansion of the hydraulic fluid, and as temperature falls to let the hydraulic fluid in the casing 22 contract, the piston 45R moves left to absorb contraction of the hydraulic fluid, thereby air can be securely prevented from being mixed into the hydraulic fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane pump in which a rotor having a plurality of radially arranged vanes is rotatably housed in a space surrounded by a cam ring and side plates inside a casing.

[0002]

2. Description of the Related Art In such a vane pump, hydraulic oil thermally expands and contracts due to a temperature difference between an operation and a stop. Therefore, when the hydraulic oil expanded due to a rise in temperature contracts due to a decrease in temperature, it is sucked into the casing. There is a problem that the trapped air mixes with the hydraulic oil. In order to absorb a change in the volume of hydraulic oil based on a temperature difference, a vane pump casing provided with a variable volume reservoir is disclosed in Japanese Patent Application Laid-Open No. 7-125.
It is known from US Pat.

[0003]

By the way, in the above-mentioned conventional apparatus, a cover constituting a part of the casing of the vane pump is slidably supported via a disc spring and a seal member, and the inside of the cover is used as a reservoir. However, there is a problem that not only the number of parts increases but also the entire vane pump becomes large due to the cover, the disc spring, and the sealing material.

[0004] The present invention has been made in view of the above circumstances, and has as its object to prevent air from being mixed into the operating oil of a vane pump with a simple and compact structure.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a rotor is rotatably housed in a space surrounded by a cam ring and a side plate inside a casing. In a vane pump in which a radially outer end of a vane slidably supported by a plurality of vane grooves formed radially on the rotor is brought into contact with an inner peripheral surface of a cam ring, the inside of a rotor shaft supporting the rotor, One end communicates with the inside of the casing and the other end is open to the atmosphere. A cylinder is formed in the axial direction, and a piston is slidably fitted to this cylinder to expand and contract hydraulic oil in the casing due to a temperature change. Pump is characterized by absorbing the pressure by the movement of the piston.

According to the above construction, the piston is slidably fitted to the cylinder formed in the rotor shaft in the axial direction, one end of the cylinder is communicated with the inside of the casing, and the other end is open to the atmosphere. As a result, when the hydraulic oil in the casing expands or contracts due to a temperature change, the piston moves in the cylinder and absorbs the change in the volume of the hydraulic oil, so that air is easily mixed into the hydraulic oil with a simple and compact structure. Can be prevented.

According to the second aspect of the present invention,
In addition to the configuration of claim 1, a pair of rotor shafts respectively supporting a pair of rotors housed in a common casing are arranged so that their shaft ends face each other, and are formed on the pair of rotor shafts. A vane pump is proposed in which a piston is slidably fitted to each of the cylinders.

According to the above construction, the pistons are slidably fitted to the cylinders formed on the pair of rotor shafts arranged so that the shaft ends are opposed to each other, so that the relative movement of the pair of pistons is improved. The change in the volume of the hydraulic oil that can be absorbed by the separation can be increased.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 13 show a first embodiment of the present invention. FIG. 1 is a skeleton diagram of a power transmission device of a four-wheel drive vehicle, and FIG. 2 is a longitudinal sectional view of a hydraulic coupling device. 3 is a sectional view taken along line 3-3 in FIG. 2, and FIG.
5, FIG. 5 is a sectional view taken along line 5-5 of FIG. 2, FIG. 6 is an enlarged view of a main part of FIG. 2, FIG. 7 is a sectional view taken along line 7-7 of FIG. 6, FIG. FIG. 9 is a perspective view of an orifice plate, FIG.
1 is a graph for explaining the operation of the orifice plate, FIG.
2 is an enlarged sectional view taken along line 12-12 of FIG. 5, and FIG. 13 is a hydraulic circuit diagram of the hydraulic coupling device.

As shown in FIG. 1, a four-wheel drive vehicle V has an engine E disposed horizontally at the front of the vehicle body and an engine E
And a transmission M coupled to the right side surface of the transmission.
A first power transmission system D _{1 for} transmitting the driving force of the transmission M to the left and right front wheels W _FL and W _FR as main driving wheels includes a first spur gear 2 provided on an output shaft 1 of the transmission M, and a first spur gear 2. Second spur gear 3 meshing with
A bevel gear type front differential 4 driven by the second spur gear 3, and a front wheel W extending left and right from the front differential 4 as a main drive wheel.
It is composed of left and right axles 5 _L and 5 _R connected to _FL and W _FR .

A second power transmission system D for transmitting the driving force of the first power transmission system D ₁ to rear wheels W _RL and W _RR as auxiliary driving wheels.
Reference numeral ₂ denotes a third spur gear 6 provided in a differential box of the front differential 4, a fourth spur gear 7 meshing with the third spur gear 6, a first bevel gear 8 which rotates integrally with the fourth spur gear 7, and a first bevel gear 8 A second bevel gear 9 meshing with a propeller shaft 10 having a second bevel gear 9 at the front end and extending rearward of the vehicle body; a third bevel gear 11 provided at the rear end of the propeller shaft 10;
A fourth bevel gear 12 meshing with the bevel gear 11;
Comprising a hydraulic coupling device H which is driven by the bevel gear 12, the rear wheels W _RL extends horizontally from the hydraulic coupling device H, and W left and right axles 13 _L connected to the _RR, 13 _R.

Next, the structure of the hydraulic coupling device H will be described with reference to FIG.

The hydraulic coupling device H is provided with a casing 24 formed by connecting a substantially disc-shaped left casing 21 and a substantially cup-shaped right casing 22 with bolts 23. It is rotatably supported in the housing 20 by bearings 19 _L, 19 _R. The right casing 22 is fastened together with the fourth bevel gear 12 by bolts 23. Therefore, the rotation of the propeller shaft 10 is transmitted to the casing 24 via the third bevel gear 11 and the fourth bevel gear 12. And the right end of the left rotor shaft 14 _L passing through the central portion of the left casing 21 is connected to the axle 13 _L of the left rear wheel W _RL, is connected to the axle 13 _R of the right rear wheel W _RR central portion of the right casing 22 and the left end of the right rotor shaft 14 _R penetrating the opposes coaxially inside the casing 24.

The needle bearing 25 left through _L rotatably supported by the left casing 21 rotor shaft 1
4 _L is the left casing 21 left side of the flange 14 ₁ formed in the intermediate portion through the thrust washer 26 _L
, And a seal member _27L is disposed between the outer peripheral surface and the left casing 21. Right rotor shaft which is rotatably supported by the right casing 22 via a needle bearing 25 _R 14 _R is thrust washer 26 is a right side surface of the flange 14 ₁ formed in the middle portion _R
The seal member 27 </ b> _R is disposed between the outer peripheral surface of the right casing 22 and the right casing 22 via the right casing 22.

Inside the casing 24, a left vane pump is provided.
P_LAnd right vane pump P_RAre arranged symmetrically
You. That is, the first left side is inside the casing 24.
Plate 28_L, Left cam ring 29_L, 2nd side play
Port 30, right cam ring 29 _RAnd right first side play
Port 28_RAre stacked immovable from side to side, and they are
Both ends fit into left casing 21 and right casing 22
6 linear shafts 31 ... (see FIG. 3)
Is prevented from rotating. Left rotor shaft 1
4_LRotor 32 spline-coupled to_LBut left first
Side plate 28_L, Left cam ring 29_LAnd the second
Rotatably stored in the space surrounded by the side plate 30
And the right rotor shaft 14_RIs splined to
Right rotor 32_RBut the right first side plate 28_R,right
Cam ring 29_RAnd surrounded by the second side plate 30
Is rotatably stored in a closed space. 2nd side plate
30 is the left vane pump P_LAnd right vane pump P_RTo
It is a common component, and a bush 33 is provided on its inner peripheral surface.
Via the left rotor shaft 14_LAnd right rotor shaft
14_RAre supported so as to be rotatable relative to each other.

Next, detailed description of the structure of the right vane pump P _R with reference also to FIGS. Since the structure of the left vane pump P _L is the structure and the left and right mirror-symmetrical right vane pump P _R, duplicate explanation is omitted. Corresponding components of the right and left vane pumps P _R and P _L have the same reference numerals with the respective suffix “ _R ”.
And the suffix " _L ".

The inner peripheral surface of the right cam ring 29 _R has become a general triangular, circular right rotor 3 housed therein
Between the 2 _R, 3 pieces of working chambers 34 _R spaced by 120 ° in the circumferential direction ... is formed. Right rotor 32 has eight respective vane grooves 32 ₁ ... in the plate-shaped vanes 35 ... formed radially in _R is slidably supported, they vanes 35 ... radially outer ends of the right cam ring 29 _R Sliding contact with the inner peripheral surface of Right in the first left side of the side plate 28 _R and the right side surface of the second side plate 30, the vanes 35
Radially outer end so as to close contact with the inner circumferential surface of the right cam ring 29 _R to each annular vane push-up port 28 _1, 3
0 ₁ is formed. These vane push-up ports 28 ₁ , 3
0 ₁ communicates with the bottoms of the eight vane grooves 32 ₁ ... Of the right rotor 32 _R. Also in order to close contact with the inner circumferential surface of the right cam ring 29 _R a radially outer end of each vane 35, the coil spring 36 is mounted under compression between the radially inner end of the bottom and the vane 35 of the vane grooves 32 _1.

[0019] As is apparent from FIGS. 6-8, the cross-sectional shape of the coil spring 36 is oval with a shorter diameter d ₂ in the circumferential direction has a major axis d ₁ in the axial direction of the right rotor 32 _R Shaped. The minor diameter d of the coil spring 36
₂ is set to be substantially equal to the groove width of the vane grooves 32 _1,
This prevents the coil spring 36 from falling down in the circumferential direction. Moreover the inclination of the axial direction of the coil spring 36, the major diameter d ₁ is reliably prevented by that along the axial direction. The radially outer end of the coil spring 36 is fitted into a trapezoidal cutout 35 ₁ (see FIG. 6) formed at the radially inner end of the vane 35, thereby positioning the coil spring 36 in the axial direction. be able to.

By making the cross section of the coil spring 36 elliptical as described above, the capacity can be increased as compared with a coil spring having a circular cross section that can be arranged in the same space. As a result, increase the number of coil springs to increase the capacity,
There is no need to increase the wire diameter, reduce the number of windings, or lengthen the set length. The number of components increases as the number of coil springs increases, and the coil springs increase as the wire diameter increases. It is possible to prevent an increase in the contact height of the steel, an increase in plastic deformation, an increase in plastic deformation due to a decrease in the number of windings, an increase in the number of processing steps for the vane due to a longer set length, and a fall of the coil spring. it can.

Further radial Since the external notch 35 ₁ of the vane 35 to be fitted is formed in a trapezoidal shape, a coil spring 36 which is compressed notch 3 of the coil spring 36
5 not only from biting ₁ can be prevented, it is possible to automatically center the coil spring 36 in the axial direction.

[0022] As is apparent from FIGS. 2 to 4 and 10, on the right side surface of the second side plate 30, 3 facing each three working chambers 34 _R ... circumferential ends of the right vane pump P _R The three suction ports 37 _R ... And the three discharge ports 38 _R. Two adjacent working chambers 34
Suction port 3 provided at the opposite part of _R , 34 _R
7 across the _R and the discharge port 38 _R, the orifice plate supporting groove 39 _R extending in the radial direction is recessed. Orifice plate supporting groove 39 _R comprises a support part 39 ₁ located radially outward, and a groove portion 39 ₂ which extend radially inward from the support portion 39 _1.

The left and right vane pumps P_L, P_RIs
When the engine rotates forward, the hydraulic oil is supplied to the suction port 37._L, 37_RSucking from
Enter and discharge port 38_L, 38_RDischarge from the
Discharge port 38 at reverse rotation_L, 38_RInhaled from
And suction port 37_L, 37 _RDischarge from.

As shown in FIG. 9, the orifice plate support
Holding groove 39_ROrifice sprayer that can swing freely
G 40_RIs a partial columnar fulcrum 40₁And this fulcrum
40 ₁Plate portion 40 extending from_TwoIs composed of
Valve section 40_TwoThe first orifice that connects both sides
Is 41_RAre formed to penetrate. Also orifice
Plate 40_RValve section 40_TwoNotch 4 on one edge of
2 is given. As shown in FIG. 10, having the above structure
Orifice plate 40_RIs the fulcrum 40₁Is an orifice
Splat support groove 39_RSupport 39₁To the valve
40_TwoIs the orifice plate support groove 39_RGroove 39_Two
Swings inside the.

As is apparent from FIGS. 3 and 6, the orientation
Fiss plate 40_RFulcrum 40 ₁Radially outside of
The half part is the right side that contacts the right side of the second side plate 30.
Cam ring 29_RIs held down by This
Orifice plate 40_RIs the right rotor 32_RMove to the side
Orifice plate 40_RThe edge of
Interference with the edges of the vanes 35 is prevented.

[0026] the outer peripheral surface of the rotor 32 _R and the cam ring 2
9 because there is a slight gap between the inner peripheral surface of the _R, a gap is present between the supporting portion 39 ₁ of the orifice plate 40 _R fulcrum 40 ₁ and the orifice plate supporting groove 39 _R of inhalation port 37 _R and the discharge port 38 _R and the gap between the fulcrum 40 ₁ and the support portion 39 _1, will communicate with each other via the gap between the rotor 32 _R and the cam ring 29 _R, undesired actuation Oil leaks can occur. However, since actually fitted swingably and liquid tight to the support portion 39 ₁ of the orifice plate 40 _R fulcrum 40 ₁ and the orifice plate supporting groove 39 _R of the fulcrum 40 ₁ and the support portion 39 ₁
Undesirable leakage of hydraulic oil through the gap therebetween can be reliably prevented.

The right vane pump P orifice plate supporting groove 39 _R and the orifice plate 40 _R of _R constitutes a switching valve V _R, also left vane pump P _L orifice plate supporting groove 39 _L and the orifice plate 40 of
_L constitutes the switching valve _VL .

As is clear from FIGS. 2 and 4, the second
And three suction ports 37 _R ... right vane pump P _R that is recessed to the right side surface of the side plate 30, the third left vane pump P _L which is recessed in the left side surface of the second side plate 30
The number of suction ports 37 _L ... are disposed opposite to each other, the corresponding suction port 37 of the right vane pump P _R to _R ... and suction port 37 _L ... and left vane pump P _L is, the second side plate 30 are connected through three second orifices 43. The right vane pump P 3 of _R that is recessed to the right side surface of the second side plate 30
A number of discharge ports 38 _R ..., is recessed been the three discharge ports 38 _L ... left vane pump P _L to the left side surface of the second side plate 30 is disposed at a position facing each other, the corresponding the discharge port 38 _R of the right vane pump P _R ...
Suction port 38 of the left vane pump P _L and _L ... and is, the second
Three second orifices 4 penetrating the side plate 30
3 are connected.

The second orifices 43 are provided with suction ports 37 _{L formed} on both side surfaces of the second side plate 30.
Are formed so as to be connected between the bottom surfaces of the 37 _R and the discharge ports 38 _L and 38 _L. Therefore, there is no possibility that the second orifices 43 are blocked by the side end surfaces of the vanes 35.

[0030] As is apparent from FIGS. 2 and 5, the right to the left side surface of the first side plate 28 _R, 3 pieces of suction ports formed in the right side surface of the second side plate 30 37 _R
... and has three discharge ports 38 _R ... is three intake ports 37 _R ... and three discharge ports 38 _R ... is recessed opposite the three of the first right side plate 28 _R
Number of suction port 37 _R ... and three of the discharge port 38 _R
... is in communication with said right right side of the first side plate 28 _R via a total of six check valves 44 _R .... The check valves 44 _R are arranged from the right side of the right first side plate 28 _R to the suction port 37 _R and the discharge port 38 _R.
... allows hydraulic oil to flow to the side, and restricts the flow of hydraulic oil in the opposite direction.

As is apparent Referring also to FIG. 12, each check valve 44 _R includes a first right side plate 28 _R of the intake ports 37 _R and a discharge port 38 _R of the valve seat that is recessed in the bottom surface 28 ₂ is constructed from the valve seat 28 ₂ to be seated a check ball 58., the check ball 58 when the suction port 37 _R and the discharge port 38 _R is a high pressure closed seated on the valve seat 28 _2, inhalation port 37 _R and a discharge port 38 _R is check ball 58 becomes a low pressure to open the valve away from the valve seat 28 _2.

[0032] the first right this way, the check valve 44 _R
By providing inside the side plate 28 _R, it suppresses the length of the oil passage leading to the check valve 44 _R to a minimum, an increase in the number of parts can be minimized. Since the first right side plate 28 _R intake ports 37 _R and the discharge port 38 _R on the right rotor 32 _R of faces, check ball 5 at its right rotor 32 _R
8 can be regulated.

[0033] As is apparent from FIGS. 2 and 6, the cylinder 14 ₂ so as to penetrate the inside of the right and left rotor shafts 14 _L, 14 _R in the axial direction, 14 ₂ are formed,
The inner end of the cylinder 14 _2, 14 ₂ communicates with the internal space of the left and right vane pumps P _L, P _R, the outer end communicates with the atmosphere. Each cylinder 14 _2, 14 ₂ to the piston 45 _L, 4
5 _R are slidably fitted, and each piston 4
5 _L, 45 by two O-rings 46 and 47 supported to the annular groove 45 _1, 45 ₂ formed on the outer periphery of the _R, the piston 4
5 _L, 45 _R and the cylinder 14 _2, 14 ₂ of the sliding surface is sealed. Between the left and right of the rotor shaft 14 _L, 14 shaft end facing each of the _R, washers 48 of the piston 45 _L, 45 _R is prevented from entering the opposite side of the cylinder 14 _2, 14 in ₂ is arranged You.

Thus, the vane pump P_L, P_RFor driving
When the hydraulic oil expands due to the heat generated, one of the hydraulic oil
Part is rotor shaft 14_L, 14_RThe opposite shaft ends
Cylinder 14_Two, 14_TwoPenetrate the inside of a pair of pi
Ton 45_L, 45_RMove in the direction away from each other
Absorbs hydraulic fluid expansion. Conversely, vane pump P_L, P_Rof
When the hydraulic oil shrinks due to the temperature drop due to operation stop, a pair of
Piston 45_L, 45 _RMove toward each other
To absorb the contraction of hydraulic oil. In this way, the number of parts
The simple structure ensures the effects of thermal expansion and contraction of the hydraulic oil.
Remove it to prevent air from entering the hydraulic fluid.
Not only can the rotor shaft 14_L, 14_R
Piston 45 by effectively utilizing the internal space of_L, 45_RTo
It can be arranged compactly. In particular, a pair of pis
Ton 45_L, 45_RHydraulic fluid swells due to
Hydraulic fluid volume that can be absorbed because it absorbs tension and contraction
Can be sufficiently secured.

While the structure of the right vane pump P _R has been mainly described above, the structure of the left vane pump P _L is mirror-symmetrical to that of the right vane pump P _R , and both structures are substantially the same.

FIG. 13 shows the hydraulic coupling.
3 shows a hydraulic circuit of the device H. It is clear from the figure
So, left vane pump P_LSuction port 37_Land
Discharge port 38_LOn the left side of the second side plate 30
Orifice plate 40 provided_LFirst orifice 41
_LAnd the right vane pump P _R
Suction port 37_RAnd discharge port 38_RIs the second rhino
Orifice plate 4 provided on the right side of plate 30
0_RFirst orifice 41_RTo communicate with each other. Ma
Left and right vane pump P_L, P_RSuction port 37_L,
37_RIs a second orifice penetrating the second side plate 30
And the left and right vanes
Pump P_L, P_RDischarge port 38_L, 38_RIs the second
The second orifice 43 penetrating the id plate 30
Communicate with each other.

Either the suction port 37 _L or the discharge port 38 _L of the left vane pump P _L is provided with a switching valve V _L
Communicating with the vane push-up port 28 _1, 30 ₁ through and right vane pump P _R of the intake ports 37 _R and a discharge port 38 vane push-up port via either the high pressure side switching valve V _R of _R 28 _1, 30 Communicate with ₁ . Any low pressure side of the suction port 37 _L and a discharge port 38 _L of the left vane pump P _L communicates with the piston 45 _L, 45 _R via the check valve 44 _L provided in the first left side plate 28 _L, also right vane pump P or low pressure side of the suction port 37 _R and the discharge port 38 _R of _R is in communication with the piston 45 _L, 45 _R via the check valve 44 _R provided on the first right side plate 28 _R.

[0038] Further, the relief valve 56 _L, 56 _R and the choke 57 _L, 57 _R is provided between the vane push-up port 28 _1, 30 ₁ and the left and right of the piston 45 _L, 45 _R. The relief valve 56 _L, 56 _R are those hypothetical, constituted by a gap that occurs between the left and right rotors 32 _L, 32 _R by the left and right first side plate 28 of _L, 28 _R are deflected by a hydraulic Is done. Also said chalk 5
7 _L and 57 _R are also virtual, and are constituted by gaps between sliding portions between the left and right first side plates 28 _L and 28 _R or the second plate 30 and the left and right rotors 32 _L and 32 _R.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

[0040] In a state where the vehicle V is constant speed running, the first spur gear 2 driving force from the output shaft 1 of the engine E, the second spur gear 3, the front differential 4 and right and left axles 5 _L, 5 the right and left via the _R The power is transmitted to the front wheels W _FL and W _FR . At this time, the third of the front differential 4
The rotation of the spur gear 6 is performed via the fourth spur gear 7, the first bevel gear 8, the second bevel gear 9, the propeller shaft 10, the third bevel gear 11, and the fourth bevel gear 12 through the casing 24 of the hydraulic coupling device H (that is, left and right). cam ring 29 _L, 29 _R) rotating the.
On the other hand, the rotation of the rear wheels W _RL , W _RR driven by the frictional force received from the road surface as the vehicle V travels is rotated by the left and right axles 13 _L ,
13 is transmitted to the rotor 32 _R of the rotor 32 _L and right vane pump P _R of the left vane pump P _L via the rotor shaft 14 _L, 14 _R from _R. Front wheels W _FL, slip is not generated in the W _FR, thus front wheels W _FL, W _FR and the rear wheels W _RL, when the rotational speed of the W _RR are equal, the rotational speed and the left and right of the left and right cam ring 29 _L, 29 _R Rotor 32 _L ,
32 _R and the rotational speed is relative rotation does not occur coincident. As a result, since the left and right vane pumps P _L and P _R do not discharge the hydraulic oil, the hydraulic coupling device H does not transmit the driving force, and the vehicle V enters the front wheel drive state.

When the front wheels W _FL and W _{FR to} which the driving force of the engine E directly acts upon starting or sudden acceleration on a low friction road, the left and right hydraulic pumps P _L linked with the rotation of the front wheels W _FL and W _FR. , P _R cam rings 29 _L , 29 _R ,
Relative rotation in the forward direction occurs between the left and right hydraulic pumps P _L , P _R rotors 32 _L , 32 _R interlocked with the rotation of the rear wheels W _RL , W _RR , and the left and right vane pumps P _L , P _R inhales from the suction port 37 _L, 37 _R of the hydraulic oil discharged from the discharge port 38 _L, 38 _R. Discharge port 38 _L , 3
8 first orifice 41 hydraulic fluid discharged from the _R's left and right
_L, 41 through the _R intake port 37 _L, 37 but flows back to the _R, vane pump P of the left and right by the flow resistance at that time
_L, load P _R is generated, the load wheels W _RL of left and right rear as the driving force is transmitted to the W _RR. Thus, the front wheels W _FL , W
_{When the FR} slips, the vehicle is in a four-wheel drive state, and the traction of the vehicle V can be increased. At this time, as the diameter of the first orifices 41 _L , 41 _R decreases, the load on the left and right vane pumps P _L , PR increases, and the rear wheels W _RL , W _R
The driving force transmitted to _RR increases.

When the vehicle V makes a tight turn at low speed,
Left and right front wheels W_FL, W_FRLeft and right than the average radius of the turning trajectory of
Rear wheel W_RL, W_RRThe average radius of the turning trajectory of the
, Front wheel W_FL, W_FRLeft and right cam rings 29 connected to
_L, 29_RAnd rear wheel W_RL, W _RRLeft and right rows connected to
TA 32_L, 32_RAnd a relative rotation occurs. Moreover
Left and right rear wheels W_RL, W_RRThe turning radius of the turning
The relative rotation
The size of the roll is the left and right vane pumps P_L, P_RDifferent in
I have. At this time, the left and right vane pumps P_L, P_RDischarge
Port 38_L, 38_RThe hydraulic oil discharged from the
1 orifice 41_L, 41_RThrough the suction port 37_L,
37_RAnd the left and right vane pumps P_L, P_RBut
The difference between the discharged hydraulic oil is calculated via the second orifice 43.
Both vane pumps P
_L, P_RA large load is prevented from being generated. So
As a result, when the four-wheel drive vehicle V makes a tight turn at low speed
So-called ties, which occur due to the radius difference of the turning locus of each wheel
The corner braking phenomenon can be reduced.

For example, when the left and right front wheels W _FL , W _FR and the right rear wheel W _RR except the left rear wheel W _RL get stuck in mud, the cam ring 29 _L interlocks with the slipping front wheels W _FL , W _FR. , 29 when _R is rotated, also the right rear wheel W _RR friction addicted to muddy is decreased, the vanes 35 ... from the cam ring 29 _R, slip by the drive force transmitted through the rotor 32 _R and the rotor shaft 14 _R Resulting in. However, the left rear wheel W _RL on a road with a high coefficient of friction
Vane 35 from the cam ring 29 _L is in ..., the rotor 32 _L
And the driving force is transmitted through the rotor shaft 14 _L, it is possible to escape from mud by its driving force. That is, according to the hydraulic coupling device H of the present embodiment, the function of a so-called differential limiting mechanism (LSD) can be exhibited. At this time, the second orifice 4
The smaller the diameter of 3, the stronger the differential limiting function.

When the rotation speed of the front wheels W _FL , W _FR exceeds the rotation speed of the rear wheels W _RL , W _RR , such as at the time of starting or rapid acceleration on the low friction road, the rotors 32 _L , 32 _R. Are relatively rotated in the normal rotation direction (the direction of arrow A in FIG. 3), and FIG.
As shown in the figure, hydraulic oil is sucked from the suction ports 37 _L and 37 _R, and hydraulic oil is discharged from the discharge ports 38 _L and 38 _R. As a result, the high pressure side discharge ports 38 _L , 38 _R
And the low-pressure side suction port 37 _L, 37 switching by the differential pressure between the _R valves V _L, V orifice plate 40 _L of _R, 4
0 _{for R} swings the suction port 37 _L, 37 _R side, the discharge port 38 _L of the high pressure side, 38 _R orifice plate supporting groove 39 _L, 39 via the _R vane push-up port 30 ₁
Communicated with the communication between the vane push-up port 30 ₁ and the low-pressure side of the suction port 37 _L, 37 _R is blocked. And Thus, to urge the vane 35 ... radially outwardly by the hydraulic pressure is transmitted to the vane push-up port 30 _1, it is possible to press the tip on the inner peripheral surface of the cam ring 29 _L, 29 _R.

On the other hand, when the vehicle performs sudden braking, AB
S (anti-lock brake system)
By controlling the locked state, the front wheels W_FL, W_FRAfter
Wheel W _RL, W_RRVehicle behavior by locking earlier than
Is stabilized. Thus, the rear wheel W_RL,
W_RROf front wheel W_FL, W_FRWhen the rotation speed exceeds
Data 32_L, 32_RIn the reverse direction (the direction of arrow B in FIG. 3)
Relative rotation, and as shown in FIG.
8_L, 38_RHydraulic oil is sucked from the suction port 3
7_L, 37_RThe hydraulic oil is discharged from. As a result, high pressure
Side suction port 37 _L, 37_RAnd low pressure side discharge port 3
8_L, 38_RSwitching valve V _L, V_Rof
Orifice plate 40_L, 40_RIs the discharge port 3
8_L, 38_RThe suction port 3 on the high pressure side
7_L, 37_RIs the orifice plate support groove 39_L, 39
_RPush-up port 30 via₁To communicate with
And vane push-up port 30₁And low pressure side discharge port 38
_L, 38_RCommunication with is interrupted. Then, push up the vane
Port 30₁Vane 35 ... by the hydraulic pressure transmitted to
It is urged radially outward and its tip is_L,
29_RCan be pressed into contact with the inner peripheral surface.

By the way, the hydraulic coupling device
In the four-wheel drive vehicle V provided with the_FL, W_FRAnd
And rear wheel W_RL, W_RRLeft and right vanes according to the relative rotational speed difference
Pump P_L, P_RGenerates a load and the front wheel W_FL, W_FRAnd
And rear wheel W_RL, W_RRThe rotation speed is low from the side where the rotation speed is high
The driving force is transmitted to the other side. Therefore, at the time of sudden braking
Front wheel W by controlling braking force_FL, W_FRLet's lock first
Then, the rear wheel W_RL, W_RROf front wheel W_FL, W_FRof
When the number of rotation exceeds the rear wheel W_RL, W_RRFront wheel W from side _FL, W_FR
The driving force is transmitted to the front wheel W_FL, W_FRNo lock
And the rear wheel W_RL, W_RRThe lock is promoted
In the worst case, the front wheel W_FL, W_FRAnd rear wheel W_RL, W_RR
May lock at the same time and cause unstable vehicle behavior.
You.

In order to avoid this, in this embodiment, the front wheel
W_FL, W_FRAnd rear wheel W_RL, W_RRDepending on the direction of relative rotation of
Re vane pump P_L, P_RThe difference in the magnitude of the load
Have. That is, in the low friction road described above,
Front wheel W like when starting or sudden acceleration _FL, W_FRAfter the rotation speed
Wheel W_RL, W_RRIf the number of rotations exceeds
2_L, 32_RAre relatively rotated in the direction of arrow A in FIG.
As shown in (A), the orifice plate 40_L, 40
_RHigh pressure vane lifting port 30₁And low pressure inhalation
Port 37_L, 37_RCommunication was completely cut off
The suction port 37_L, 37_RAnd discharge port 3
8_L, 38_RIs the first orifice 41_L, 41_RJust through
And communicate with the vane pump P_L, P_REmits a heavy load
Raw front wheel W_FL, W_FRFrom rear wheel W_RL, W_RRCommunicated to
The driving force increases (see the solid line in FIG. 11).

On the other hand, when the rotational speeds of the rear wheels W _RL , W _RR exceed the rotational speeds of the front wheels W _FL , W _{FR as in} the case of the above-mentioned rapid braking, the rotors 32 _L , 32 _R are turned by arrows in FIG. rotatable with respect to the direction B, as shown in FIG. 10 (B), the communication between the high pressure vane push-up port 30 ₁ and the low pressure of the discharge port 38 _L, 38 _R is tentatively blocked by the orifice plate 40 _L, 40 _R but since the orifice plate 40 _L, 40 discharge port from the vane push-up port 30 ₁ by the cutout 42 formed in _R 38 _L, 38 _R to the hydraulic oil leaks,
The load generated by the vane pumps P _L , P _R decreases, and the driving force transmitted from the front wheels W _FL , W _FR to the rear wheels W _RL , W _RR decreases (see broken lines in FIG. 11). Thus, at the time of sudden braking, the front wheels W _FL and W _FR are locked prior to the rear wheels W _RL and W _RR , thereby preventing the vehicle behavior from becoming unstable.

[0049] Further, vane pumps P _L, the suction port with the operation of the P _R 37 _L, 37 _R (or the discharge port 3
8 _L , 38 _R ) become negative pressure, the check pressures 44 _L …, 44 _R … open and the suction port 37
_L, 37 since communicating _R (or discharge port 38 _L, 38 _R) on the piston 45 _L, 45 _R, it is possible to reliably prevent the cavitation caused by excessive negative pressure.

As described above, the second orifices 43.
Since the two side plates 30 were drilled,
Hydraulic cup with increased processing accuracy of fiss 43 ...
The operating characteristics of the ring H can be stabilized. Also the
1 orifice 41_L…, 41 _R… And second orifice
43 are concentrated on the second side plate 30
And those orifices 41_L…, 41_R…; 43…
Hydraulic cup with minimum oil passage length
Not only can the ring device H be miniaturized,
An increase in the number of parts can be minimized.

[0051] Moreover the switching valve V _L, the suction port by using a V _R 37 _L, 37 _R and the discharge port 38 _L, 38 _R
It is possible to selectively communicated with the vane push-up port 30 _1, simplification of the reduction and the oil passage of parts is possible as compared to its function in that exert a combination of a plurality of check valves. In particular, the suction port 37 _L , 3
7 _R and a discharge port 38 _L, 38 _R arranged switching valve V _L between, V _R of the orifice plate 40 _L, 40
_Since the first orifices 41 _L and 41 _R are formed using _R , the length of the oil passage can be reduced to a minimum.

Further, since the left and right vane pumps P _L and P _R share the second side plate 30, the number of parts can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG.

The second embodiment differs from the first embodiment in the structure of the pistons 45 _L and 45 _R , and the other structure is the same as the first embodiment. Piston 4 of the second embodiment
5 _L, 45 _R is provided with one annular groove 45 ₁ and one of the annular sliding surface 45 _3, O-ring 46 and the annular sliding surface 45 ₃ and the cylinder 14 ₂ is supported in an annular groove 45 ₁ , 14
Slide into contact with ₂ .

According to the second embodiment, the same operation and effect as those of the first embodiment can be achieved.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the vane pumps P _L and P _R of the hydraulic coupling device H are exemplified.
The present invention can be applied to a vane pump for any other use.

[0058]

As described above, according to the first aspect of the present invention, the piston is slidably fitted to the cylinder formed in the rotor shaft in the axial direction, and one end of the cylinder is connected to the casing. When the hydraulic oil in the casing expands or contracts due to temperature changes, the piston moves in the cylinder and absorbs changes in the volume of the hydraulic oil by communicating with the inside and opening the other end to the atmosphere. The structure can reliably prevent air from being mixed into the hydraulic oil.

According to the second aspect of the present invention,
Since the pistons are slidably fitted to cylinders formed on a pair of rotor shafts arranged so that the shaft ends face each other, the volume of hydraulic oil that can be absorbed by the relative approach and separation of the pair of pistons. Change can be increased.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of a power transmission device of a four-wheel drive vehicle.

FIG. 2 is a longitudinal sectional view of a hydraulic coupling device.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 2;

FIG. 6 is an enlarged view of a main part of FIG. 2;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is a perspective view of a coil spring.

FIG. 9 is a perspective view of an orifice plate.

FIG. 10 is a diagram illustrating the operation of an orifice plate.

FIG. 11 is a graph illustrating the operation of an orifice plate.

FIG. 12 is an enlarged sectional view taken along line 12-12 of FIG. 5;

FIG. 13 is a hydraulic circuit diagram of a hydraulic coupling device.

FIG. 14 shows a second embodiment of the present invention, and corresponds to FIG.

[Explanation of symbols]

14 _L rotor shaft 14 _R rotor shaft 14 ₂ cylinder 24 casing 28 _L first side plate (side plate) 28 _R first side plate (side plate) 29 _L cam ring 29 _R cam ring 30 second side plate (side plate) 32 _L Rotor 32 _R Rotor 32 ₁ Vane groove 35 Vane 45 _L Piston 45 _R Piston

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takuya Kurokawa 19 Matsuyamacho, Moka City, Tochigi Prefecture Honda Motor Co., Ltd.Tochigi Seisakusho Co., Ltd. (72) Inventor Takeshi Mochizuki 19 Matsuyamacho Moka City, Tochigi Prefecture Tochigi Seisakusho Co. Ltd. F term (reference) 3H040 AA03 BB05 BB11 CC02 CC15 DD09 3H044 AA02 BB05 BB08 CC00 CC08 CC09 CC13 CC19 DD06 DD11 DD24 DD28

Claims (2)

[Claims] 1. A inside the cam ring (29 _L, 29 _R) of the casing (24) and the side plate (28 _L, 2
8 _R , 30) in the space surrounded by the rotor (32 _L , 3).
2 _R ) is rotatably housed, and this rotor (32 _L , 32
It is brought into contact with the radially outer end of the plurality of vane groove formed in the radially _R) (32 _1), each slidably supporting a vane (35) on the inner peripheral surface of the cam ring (29 _L, 29 _R) in the vane pump, the interior of the rotor (32 _L, 32 _R) rotor shaft which supports the (14 _L, 14 _R), one end of the casing (2
A cylinder (14 ₂ ) communicating with the inside of 4) and having the other end open to the atmosphere is formed in the axial direction, and this cylinder (14 ₂ )
The piston (45 _L, 45 _R) expansion and contraction of the hydraulic oil in the casing (24) due to temperature changes by slidably fitted to be absorbed by movement of the piston (45 _L, 45 _R) to A vane pump. 2. Housed inside a common casing (24)
Pair of rotors (32_L, 32_RSupport each)
Rotor shafts (14_L, 14_R), Those
Are arranged so that their shaft ends face each other.
Saft (14 _L, 14_R) Formed cylinder (1
4_Two) To each piston (45_L, 45 _RSelf sliding
2. The vehicle according to claim 1, wherein
Pump.