JP2610303B2 - Variable displacement vane pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable displacement vane pump.

(Prior Art) A variable displacement vane pump is configured such that when a large number of vanes (blades) radially arranged around a rotor move while contacting along the inner periphery of a cam ring as the rotor rotates,
Depending on the rotation position of the rotor, the volume of each pump chamber formed between the vanes is enlarged or reduced. Both sides of the rotor are surrounded by a valve plate and side plates, and the valve plate has a suction port formed in the enlarged area of the pump chamber and a discharge port formed in the reduced area. As a result, suction and discharge of hydraulic oil are performed.

The pump discharge amount is controlled by changing the amount of eccentricity of the cam ring with respect to the rotor axis. As the amount of eccentricity increases, the rate of change in volume of the pump chamber increases and the discharge amount also increases.

(Problems to be Solved by the Invention) By the way, in such a vane pump, leakage of hydraulic oil from a pump chamber generated between a rotating rotor and a side plate (valve plate) and also in a gap between a cam ring and a side plate. That is, the volume loss reduces the pump efficiency, and at the same time, this is one of the factors that hinder the increase in the pressure and the speed of the pump.

If the gap amount is reduced, the leakage is reduced, but so-called "galling" occurs on the contact surface between the vane edge of the rotor and the side plate. Therefore, there is a limit to the narrowing of the gap between the rotor and the side plate because the problem of "galling" at the contact surface is inevitable, which directly leads to a reduction in volumetric efficiency.

In a variable displacement vane pump, the upper and lower halves of the vane pump are separated into a discharge area and a suction area in the sliding direction of the cam ring, and are completely separated into a high pressure side and a low pressure side. The pressure generates a large radial force in a direction orthogonal to the rotor axis.

The cam ring is pressed against one of the sliding surfaces by this radial reaction force, and a load due to the reaction force acts on the bearing of the pump shaft that drives the rotor. As a result,
This significantly deteriorates the dynamic characteristics of the cam ring, requires a large driving force to slide the cam ring, and accelerates the wear of the pump shaft bearing, whether it is a rolling bearing or a sliding bearing, and shortens the bearing life. Was causing problems.

An object of the present invention is to solve such a problem.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a pump housing in which a main pump attached to a main drive shaft and a slave pump attached to a driven shaft are arranged in parallel. The main pump is integrally provided with a main rotor, a rotary valve plate and a rotary side plate for holding the main rotor together with the main rotor, and the driven pump is also driven by the driven shaft. Similarly, the rotary valve plate and the rotary side plate are integrally mounted, and the rotary valve plates of the main and slave pumps are brought into rolling contact with each other, and the rotary side plates are also brought into rolling contact with each other, so that the vanes of the main rotor and the slave rotor are inscribed. A cam ring having two cam surfaces is disposed between the rotary valve plate and the rotary side plate, and driving means for displacing the cam ring in a direction orthogonal to the main and driven shafts is provided. Movable valve Board suction,
A passage port communicating with a pump chamber formed between the vanes with respect to a discharge port is formed in each rotary valve plate.

(Operation) When the main drive shaft rotates, the driven shaft also rotates in the opposite direction, so that the subordinate pump is driven simultaneously with the main pump. When the main and slave rotors rotate, the rotary valve plate and the rotary side plate also rotate integrally with the rotor. The vanes change the volume of the pump chamber while moving along the inner circumference of each cam surface of the cam ring. Hydraulic oil enters and exits each pump chamber through a passage port formed in each rotary valve plate, and sends out hydraulic oil sucked from a suction port of each movable valve plate that comes into contact with each rotary valve plate to a discharge port.

Since the main pump and the slave pump rotate in opposite directions,
The discharge area and the suction area are on opposite sides, and for a common cam ring, the radial force in the direction orthogonal to the main and driven axes based on the discharge pressure of each pump cancels out, and the main and slave rotors are equal to the direction facing each other. Force acts. Since the radial force acting on the main and driven shafts is received by the rotating valve plate and the rotating side plate which are in rolling contact with each other, by setting them to the same diameter, a pure rolling bearing without any slip can be constituted.

A vane installed around the primary and secondary rotors,
No relative movement occurs in the circumferential direction between the rotary valve plates and the side plates, and the vanes simply reciprocate in the radial direction. For this reason, even if the gap between the vane and the rotary valve plate or the side plate is reduced, the "galling" phenomenon is unlikely to occur. Therefore, leakage of hydraulic oil from around the pump chamber is prevented, and the pump volume efficiency can be greatly improved.

(Embodiment) FIGS. 1 to 7 show an embodiment of a variable displacement vane pump according to the present invention.

As shown in FIG. 1, a main pump A and a subordinate pump B which are linked to each other are arranged in parallel in a cylindrical pump housing 11 whose both ends are closed by cover plates 9 and 10.

First, the main pump A will be described. The main drive shaft 1A of the main pump A is rotatably disposed through one cover plate 9.

A rotary valve plate 2A is provided with a main rotor 4A integrally provided on the main drive shaft 1A and inserted so as to sandwich it from both sides.
And the rotating side plate 3A are integrally connected by a key 17A.

As shown in FIG. 2, a number of vanes 5A are radially arranged around the main rotor 4A at equal intervals.
5A reciprocates in the groove of the main rotor 4A while the tip slides along the inner surface of the main cam surface 6A of the cam ring 6.

As described later, the cam ring 6 has a circular main cam surface 6A and a circular cam surface 6B, and is configured to move (slide) in a direction orthogonal to the axis of the main driving shaft 1A and the driven shaft 1B. Construct a variable capacity mechanism.

The plurality of pump chambers 13A defined by the cam ring 6, the main rotor 4A, and the respective vanes 5A change in volume with the rotation of the main rotor 4A, draw in hydraulic oil in the process of expanding the volume, and reduce the volume. The hydraulic oil is discharged in the process.

Corresponding to each of the pump chambers 13A, as shown in FIG. 3, the same number of passage ports 14A are formed in the rotary valve plate 2A in the axial direction on the same circumference so as to communicate therewith. .

A movable valve plate 8A that does not rotate but is displaced in the axial direction is provided outside the rotary valve plate 2 in contact with the rotary valve plate 2. The movable valve plate 8A has an arc-shaped suction port 15 as shown in FIG.
A and a discharge port 16A are respectively formed, and the passage port 14A is connected to these ports 15A and 16A in order with the rotation of the rotary valve plate 2A.

The suction port 15A has a suction hole 18 formed in the cover plate 10 via a merging plate 20 described later, and a discharge port.
16A is also connected to the discharge hole 19.

A movable side plate 7A which does not rotate but is movable in the axial direction is provided outside the rotary side plate 3A.

Next, a slave pump B which rotates in conjunction with the main pump A will be described. The basic structure of the slave pump B is exactly the same as that of the main pump A.
4B is mounted, the rotary valve plate 2B and the rotary side plate 3B are inserted, and are integrally fixed by the key 17B. A vane 5B is arranged around the slave rotor 4B so as to contact the inner surface of the slave cam surface 6B of the cam ring 6, and a pump chamber 13B is defined between the vanes.

7B is a movable side plate, 8B is a movable valve plate, 17B is a key, 14B
Is a passage port, 15B is a suction port, 16B is a discharge port, and the suction port 15B and the discharge port 16B pass through the merging plate 20 and, similarly to the main pump A, the suction hole 18 and the discharge hole 19.
To each other.

A main driving gear 21A is formed on a part of the rotating side plate 3A of the main pump A so that the main pump A rotates so that the sub pump B also rotates.
It is formed on a part of the rotary side plate 3B of the slave pump B. Therefore, when the main driving shaft 1A rotates, the driven shaft 1B starts to rotate in the same direction in the opposite direction.

2 to 4, the main pump A and the sub-pump B rotate in opposite directions so that the lower half of the main drive shaft 1A in the main pump A is in the suction area and In the pump B, the volumes of the pump chambers 13A and 13B are increased as they move in the rotation direction so that the upper half of the driven shaft 1B becomes the suction area.

Therefore, in the main pump A, the upper half of the leading shaft 1A is the discharge area, and in the slave pump B, the lower half of the driven shaft 1B is the discharge area.

As shown in FIG. 5, a vertically long suction passage 30 connected to each suction port 15A and 15B is formed at the center of the merging plate 20 disposed outside the movable valve plates 8A and 8B. , An annular discharge passage 31 is formed. The annular discharge passage 31 is connected to discharge ports 16A and 16B via passages 31A and 31B, respectively.

Further, the suction passage 30 of the merging plate 20 is
The suction hole 18 and the discharge passage 31 are also connected to the discharge hole 19.

33A and 33B are seal rings for sealing between the suction passage 30 and the discharge passage 31.

As shown in FIGS. 1 and 3, the rotary valve plates 2A and 2B of the main pump A and the sub-pump B are set to have the same outer diameter, and are kept in rolling contact with each other so as not to cause slippage on their rotating surfaces. Similarly, the rotating side plates 3A and 3B are also kept in rolling contact.

Further, the housing 11 supports the outer circumference of each rotary valve plate 2A and 2B, and has a partially cut-out cylindrical bearing sleeve 35A and 35B.
Are provided, and the outer peripheries of the rotary side plates 3A and 3B are similarly supported by the bearing sleeves 35A and 35B.

As shown in FIG. 2, a hydraulic piston 25 and a balance spring 26 are provided to slide the cam ring 6 in a direction orthogonal to the main drive shaft 1A and the driven shaft 1B. When the pressure increases, the cam ring 6 is displaced against the balance spring 26.

In this embodiment, a hydraulic passage 27A formed in the cover plate 10 and a hydraulic passage 27B
, The pressure of the discharge hole 19 is introduced into the oil chamber 27, so that as the discharge pressure increases, the hydraulic piston 25 is displaced to reduce the amount of eccentricity of the cam ring 6, thereby reducing the discharge amount. I do.

28A and 28B are flat needle bearings for guiding the upper and lower surfaces of the cam ring 6 so that the cam ring 6 can move smoothly.

By the way, in the present invention, the rotary valve plates 2A, 2B located on both sides of the main and slave rotors 4A, 4B and the rotary side plates 3A, 3B do not cause relative rotation between the master and slave rotors 4A, 4B, For these, the vanes 5A and 5B simply reciprocate, so that the moving speed of the vanes 5A and 5B is greatly reduced, and the axial gap between the main and slave rotors 4A and 4B is set to almost zero. Even so, the "galling" phenomenon unlike the related art does not occur.

However, the cam ring 6, the rotary valve plates 2A and 2B and the rotary side plate 3
A sliding gap between A and 3B is required, but in this case also, mutual contact does not have the problem of "galling" due to surface contact, so that the gap can be reduced. In addition, although relative rotation occurs between the rotary valve plates 2A, 2B and the movable valve plates 8A, 8B and between the rotary side plates 3A, 3B and the movable side plates 7A, 7B, since these contacts are surface contacts, Similarly, the occurrence of "galling" is extremely small.

However, as the gap in the axial direction due to the wear of the contact surface increases, the leakage loss of the hydraulic oil increases. As shown in FIGS. 1 and 4, as shown in FIGS. O-ring 40A on the outer surface of movable valve plates 8A and 8B
And back pressure chambers 41A and 41B surrounded by 40B, respectively.

The back pressure chambers 41A and 41B communicate with the discharge ports 16A and 16B, respectively, so that the pump discharge pressure acts from the outer surfaces of the movable valve plates 8A and 8B.

In this case, the discharge ports 16 are provided on the inner surfaces of the movable valve plates 8A and 8B.
Since the discharge pressure according to the area of A, 16B acts, to press the movable valve plates 8A, 8B against the rotary valve plates 2A, 2B side so as to keep the gap of the contact surface constant, the back pressure chamber 41A , 41B must be larger than the areas of the discharge ports 16A, 16B, and the pressure application centers must be set to coincide with each other.

On the other hand, based on the pressing force and the like, the movable side plates 7A, 7B receive a thrust force acting on the contact surface with the cover plate 9 from the opposite rotating side plates 3A, 3B via the movable side plates 7A, 7B. Arc groove on the contact surface with the cover plate 9
43A and 43B are formed, in which pump chambers 13A and 13B are formed by passages 44A and 44B formed through the rotating side plates 3A and 3B.
The high pressure from the discharge area is guided to form a hydrostatic thrust bearing.

 The configuration is as described above. Next, the operation will be described.

With the rotation of the main drive shaft 1A, the main rotor 4A of the main pump A, the rotary valve plate 2A and the rotary side plate 3A rotate integrally. Rotating side plate
The rotation of 3A causes the rotating side plate 3B of the slave pump B to rotate via the driven gear 21B meshing with the main driving gear 21A, and the driven rotor 4B rotates in the opposite direction to the main rotor 4A together with the driven shaft 1B.

The vanes 5A, 5B around the main and slave rotors 4A, 4B reciprocate in the radial direction according to the amount of eccentricity of the cam ring 6, thereby expanding and reducing the volume of the pump chambers 13A, 13B. Hydraulic oil from suction ports 15A, 15B formed in movable valve plates 8A, 8B
Hydraulic oil sucked into the pump chambers 13A and 13B in the suction area in the expansion process through the passage ports 14A and 14B of the passages 2A and 2B, and extruded from the pump chambers 13A and 13B in the discharge area in the reduction process,
It is sent out to the discharge ports 16A, 16B via the passage ports 14A, 14B. The suction ports 15A and 15B are the suction passage of the junction plate 20
30 and the discharge ports 16A and 16B merge in the discharge passage 31, so that the hydraulic oil from the suction hole 18 is diverted from each other and sucked into the main pump A and the sub pump B, and then pressurized by each. The hydraulic oil that has joined again joins and is pressure-fed to the discharge hole 19.

The pump discharge amount changes in proportion to the eccentric amount of the cam ring 6, and the discharge amount increases as the eccentric amount increases.

By the way, the rotation directions of the main pump A and the slave pump B are opposite, and as shown in FIG. 7, the inside between the main drive shaft 1A and the slave shaft 1B is a suction area, and the outside is a discharge area. Is set to

For this reason, in the main pump A, the upper half becomes high pressure and the lower half becomes low pressure with respect to the axis of the driving shaft 1A, and conversely, in the pump B, the upper half becomes low pressure and the lower half becomes high pressure. Based on the differential pressure, a downward force Fa is generated on the main rotor 4A and an upward force Fb is generated on the slave rotor 4B, and the upward force F is applied to the cam ring 6 by the main pump A as a reaction force.
a ', and a downward force Fb' is exerted by the slave pump B.

The reaction forces Fa 'and Fb' acting on the cam ring 6 are equal to each other even if the directions are reversed, so they are offset each other. In FIG. 2, no radial force is applied to the cam ring 6 either above or below. By the driving force of the hydraulic piston 25, the cam ring 6 can be smoothly displaced in the left-right direction in the drawing.

Also, an inward force acting on the main rotor 4A and the slave rotor 4B
Depending on Fa and Fb, rotary valve plates 2A and 2B and rotary side plates 3A and 3B
Rotate while receiving radial force toward each other, but because they have the same outer diameter, they come into pure rolling contact with each other without slipping. As small as possible, wear on the surface is eliminated, and the life of the bearing together with the outer peripheral bearing sleeves 35A and 35B is significantly prolonged.

In addition, in order to support such a load, the rotary valve plate 2A,
2B and the rotating side plates 3A and 3B are formed thicker in the axial direction than the main and slave rotors 4A and 4B.

Since the rotary valve plates 2A and 2B on both sides of the main and slave rotors 4A and 4B and the rotary side plates 3A and 3B rotate in the same manner, the vanes 5A and 5B and the rotary valve plates 2A and 2B and the rotary side plates 3A and 3B Since there is no relative rotation between the vanes and the vanes 5A and 5B simply reciprocate in the radial direction, even if the sliding gap is made small, almost no "galling" occurs, and as a result, through the sliding surface Of the operating oil can be significantly reduced.

In addition, the cam ring 6, the rotary valve plates 2A and 2B and the rotary side plate 3
Since A and 3B are in surface contact with each other, the problem of galling does not occur even if the gap in the axial direction of the sliding surface is reduced, so that leakage of hydraulic oil through the sliding surface of the cam ring 6 is similarly reduced. be able to.

As a result, the volumetric efficiency of the pump is improved, and the pressure and the speed can be further increased.

(Effects of the Invention) As described above, according to the present invention, the rotary valve plate and the rotary side plate located on both surfaces of the rotor are integrally rotated, so that the movement of the vane with respect to the side component is rotated and reciprocated. From the combined movement with the movement, it becomes a single direct reciprocating movement,
Since the relative speed of the sliding surface is greatly reduced, even if the sliding gap is reduced, a problem such as "galling" and eventually seizure does not occur, thereby increasing the reliability of the pump. In addition, by reducing the gap between the rotor sliding surfaces in this manner, even if the relative sliding surfaces increase, volumetric efficiency can be improved by reducing leakage of hydraulic oil from around the pump chamber, and at the same time, the pump Higher pressure and higher speed can be realized. By canceling the influence of the pump discharge pressure acting on the cam ring, the dynamic characteristics of the cam ring are improved, and smooth operation is guaranteed. Since the bearings of the drive shaft and the driven shaft can be pure rolling contact bearings between the rotary valve plates and the rotary side plates, wear of the bearings is reduced, and the life is remarkably improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is a sectional view taken along the line AA of FIG.
FIG. 4 is a sectional view taken along the line CC, and FIG.
FIG. 6 is a cross-sectional view, FIG. 6 is an arrow F view, and FIG. 1A …… Driving shaft, 1B …… Driving shaft, 2A, 2B …… Rotary valve plate, 3A,
3B: rotating side plate, 4A: main rotor, 4B: slave rotor, 5
A, 5B Vane, 6 Cam ring, 6A, 6B Cam surface, 7A, 7B Movable side plate, 8A, 8B Movable valve plate, 11 Pump housing, 14A, 14B Passage port , 15A, 15B ……
Suction port, 16A, 16B …… Discharge port.

Claims (1)

(57) [Claims] A gear means for reversing the rotation of the main drive shaft and transmitting the same to the driven shaft is provided inside the pump housing in parallel with a main pump mounted on the main drive shaft and a slave pump mounted on the driven shaft. The main pump has a main rotor, a main rotor, and a rotary valve plate and a rotary side plate that sandwich the main rotor. The sub pump also has a driven shaft with the rotor, the rotary valve plate, and the rotary side plate mounted integrally. The rotating valve plates of the main and slave pumps are in rolling contact with each other, and the rotating side plates are also in rolling contact with each other, so that the vanes of the main rotor and the slave rotor are inscribed.
A cam ring having two cam surfaces is disposed between the rotary valve plate and the rotary side plate, and driving means for displacing the cam ring in a direction orthogonal to the main and driven shafts is provided. A variable displacement vane pump, wherein a passage port for connecting a pump chamber formed between the vanes to a suction and discharge port of a valve plate is formed in each rotary valve plate.