JPH0740703Y2 - Vane pump - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to a vane pump suitable for a power steering device of an automobile or the like, and particularly, reduces noise generated due to a timing shift of suction and discharge pump actions. The vane pump.

(Prior Art) Most of the pumps recently adopted as power sources for power steering devices are vane pumps. Vane pumps are widely used because they have advantages such as small size, light weight, quietness, simple device, high speed rotation, good volume efficiency at low speed rotation, and sufficient reliability.

A conventional vane pump of this type is disclosed in, for example, JP-A-59
-180090 publication. In this vane pump, a cam ring is provided in the housing, a rotor having a plurality of vanes is housed in the cam ring, and two adjacent vanes that are in sliding contact with the cam surface of the cam ring form a pump chamber. Then, the rotor is driven to rotate by the drive shaft, so that the pump action of sucking and discharging the hydraulic oil filled in the pump chamber is sequentially executed.

(Problems to be solved by the invention) However, in such a conventional vane pump, the number of pump chambers communicating with the discharge section is determined by the position of the discharge port and the positional relationship between the opening section and the vane interval. However, the pressing force of the hydraulic fluid filling the pump chamber fluctuates according to the rotational position of the rotor, which causes a problem that noise and vibration increase.

That is, in the vane pump with 10 vanes, the above fluctuations occur 20 times for each rotation of the rotor,
Repeated radial loads are applied to the rotor and cam ring, causing vibrations. Further, the two discharge sections, which should be at the axially symmetrical positions, may be displaced from each other in the timing of the discharge action of the above two discharge sections due to the processing accuracy and assembly accuracy of the rotor, the cam ring and the vane. Deviation does not balance with the other pressing force, making the vibration even greater and
Generates high-order noise. Furthermore, in the suction section, the amount of leaked liquid that leaks into the gap between the rotor and the side plate is changed,
Since the pressure of the hydraulic fluid fluctuates, it is difficult to take measures to suppress the vane pump and improve its quietness.

Here, the above problems will be specifically analyzed with reference to FIG. FIG. 6 is a sectional view of the inside including the cam ring of the vane pump. In FIG. 6, 1 is a cam ring, and the rotor 2 is housed inside the cam ring 1. The rotor 2 has vane slots 2a formed at equal intervals on the circumference of the rotor 36, and ten vanes 3 are held in the vane slots 2a so as to be retractable. The tip of the vane 3 is in sliding contact with the cam surface 1a of the cam ring 1, and the cam surface 1a
A pump chamber 4 is formed by two vanes 3 adjacent to each other. Then, the rotor 2 is rotationally driven by the drive shaft 5. Reference numerals 6 and 7 denote a suction port and a discharge port formed on a side plate (not shown), and the suction port 6 and the discharge port 7 communicate with the pump chamber 4 which is rotationally moved at that position. In the figure, A is a suction section, B is a discharge section, D is a large arc closed section (first closed section),
d is a small circular arc closing section (second closing section).

Now, consider the case where the rotor 2 rotates in the direction of the arrow (clockwise) together with the drive shaft 5 as shown in FIG. 6, and pay attention to the relationship between the rotation angle θ of the rotor 2 and the hydraulic oil pressure at this time. While explaining the phenomenon.

First, when the pair of vanes 3 are vertically positioned as shown in the figure, assuming that the vertical upper position is 0 ° (360 °), the discharge section is θ = 18 ° to 72 °, 198 ° to 252 °, and the suction section. Is θ =
It becomes 108 ° -162 °, 288 ° -342 °. At this time, the number of pump chambers 4 in each of the discharge section and the suction section is one discharge section: 3 chambers and one suction section: 2 chambers.

On the other hand, the number of pump chambers 4 in the discharge and suction sections when the rotor 2 is slightly rotated from the above position changes such that one discharge section: two chambers and one suction section: three chambers.

That is, each time the rotation angle θ of the rotor 2 advances by 18 °, the number of pump chambers 4 in the discharge and suction sections changes as follows: discharge section = 3 chambers → 2 chambers → 3 chambers ... suction section = 2 chambers → 3 chambers → 2 chambers ... and so on, and this change occurs 20 times for each revolution of the rotor 2.

Next, the pressure change of the hydraulic oil in the pump chamber 4 due to the rotation of the rotor as described above will be described.

First, the pressure of the hydraulic oil in the discharge section is high, and the high-pressure hydraulic oil causes the outer peripheral surface of the rotor 2 and the cam surface 1a of the cam ring 1 corresponding to the discharge section to be radially inward and radially outward, respectively. It acts as a pressing force F, F'which pushes toward each other, and these F, F'are balanced. However, as the number of the pump chambers 4 changes, the pressing forces F and F'change as the number of the pump chambers 4 increases / decreases every 18 degrees as shown in FIG. When
Letting F _{A be} the case of two chambers and F _B , the relationship between these pressing forces is as follows.

Therefore, the change in the pressing force (pressure load) in the radial direction occurs 20 times each time the rotor 2 makes one revolution, and a high-order repeated radial load is applied to the rotor 2 and the cam ring 1 to cause vibration.

Further, unless the accuracy of the shape of the cam ring 1 and the accuracy of the arrangement of the vanes 4 of the rotor 2 and the accuracy of assembling the both are increased, the timings of the pressing forces F and F'generated in each discharge section deviate from each other and are shown in FIG. Such a pressing force F, F ′ causes a region where the pressure is not balanced, which causes the above-mentioned vibration to become extremely large.

Further, the change in the number of pump chambers 4 in the suction (low pressure) section changes the amount of hydraulic oil that leaks into the gap where the rotor 2 and the side plate (not shown) come into contact, so the pressure of the hydraulic oil in the vane pump changes. The variation of the amount of leaked oil at this time is as shown in FIG.

(Object of the Invention) Therefore, in the present invention, the openings of the suction section and the discharge section and the closed section between the suction section and the discharge section are processed to be an integral multiple of the interval of the vanes, and the positions thereof are appropriately determined. This makes the timing of inhalation and exhalation the same,
The purpose of the present invention is to suppress the fluctuation of the pressing force of the hydraulic fluid and reduce the vibration, noise and pressure fluctuation of the hydraulic fluid due to the fluctuations, thereby improving the damping and quietness of the vane pump.

(Means for Solving the Problem) In order to achieve the above object, the vane pump according to the present invention includes a cam ring having a cam surface composed of a small circular arc, a large circular arc and a connecting curve between them, and a cam ring housing together with a cover plate. A housing to be formed, and a rotor that holds the 10 vanes that are housed in the cam ring housing and that are in sliding contact with the cam surface at equal intervals on the circumference, rotate the vanes by protruding and retracting in the radial direction, and the side of the cam ring. And a side plate having a suction port and a discharge port formed therein, a pump chamber is formed by two adjacent vanes, a cam surface, a rotor outer peripheral surface, a cover plate and a side plate, and Along with changing the volume of the pump chamber to suck and discharge hydraulic fluid,
When a section where the volume of the pump chamber increases is a suction section and a section where the volume of the pump chamber decreases is a discharge section, in a vane pump in which these sections are formed in two places, the cam ring passes through the center position in the circumferential direction of the small arc. With the diameter as a reference line, the suction port is opened from the reference line to a position of 18 ° to 90 ° in the rotation direction of the rotor, and the discharge port is set to 126 ° to 162 ° in the rotation direction of the rotor from the reference line. It was made to open at the position.

(Operation) In the present invention, the suction section is equal to the gap between three adjacent vanes, and the discharge section is equal to the gap between two adjacent vanes. As a result, the section that confines the working fluid between the end point of the suction section and the start point of the discharge section is the first closed section, and the section that confines the working fluid between the end point of the discharge section and the start point of the suction section. Is a second closed section, the first and second closed sections have the same size, and the size is equal to the gap between two adjacent vanes, and the suction section and the discharge section are equal to each other. The position is determined such that the confinement action of the hydraulic fluid in the first and second confinement sections is performed simultaneously. Therefore, the opening of the suction section and the discharge section and the closing section between the suction section and the discharge section are processed to be an integral multiple of the vane interval,
The position is appropriately determined, the number of pump chambers in the suction section and the discharge section is always kept constant, and the timings of the suction and discharge actions are made the same. Therefore, the fluctuation of the pressing force due to the working fluid in the pump chamber is suppressed, and the vibration, noise and pressure fluctuation of the working fluid due to this fluctuation are reduced. As a result, the vibration control and quietness of the vane pump are improved.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

1 to 5 are views showing an embodiment of a vane pump according to the present invention.

First, the configuration will be described. FIG. 1 is a longitudinal sectional view of the vane pump in the axial direction, and FIG. 2 is a sectional view taken along line II-II of FIG. In these figures, 11 is a vane pump, which is provided with a housing 12 and a cover plate 13, and a cover plate 13 is attached to a front surface 12a of the housing 12 by a bolt (not shown).
Is fixed.

The housing 12 is formed with a concave portion (cam ring housing portion) 14 opening to the front surface 12a, and a shaft hole provided so as to open to the center of the concave portion 14 from the side opposite to the front surface 12a. A housing-side suction passage 15 is provided in parallel with the recess 14 from the front surface 12a, and a control valve storage hole is provided at the end of the suction passage 15 and the control valve for controlling the discharge flow rate is provided in the storage hole.
16 are stored. The control valve storage hole communicates with the bottom of the recess 14 through a communication hole 18.

In addition, the housing side suction passage 15 has a housing 12
Open to the side of, and connected to the source of hydraulic oil (not shown),
The suction hole 17 is opened, and a seal drain hole (not shown) communicating with the shaft hole is opened.

The cover plate 13 is attached to the housing 12 as described above, a recess 13b is provided at the center of the mounting surface so as to face the tip of the drive shaft, which will be described later, and one end communicates with the housing-side suction passage 15 and the other end A cover-side suction passage 13a is formed that communicates with a suction port 32 that opens in each suction section of the pump described below.

Reference numeral 19 denotes a drive shaft, which penetrates the shaft hole of the housing 12 and has a central portion rotatably supported by a bearing portion 24a provided in the shaft hole of the housing 12 and a rear end of the drive shaft outside the housing 12. It is rotatably supported by a bearing 21 provided in the recess 20. Then, a spline portion is formed at the projecting end portion 19a of the drive shaft 19 so as to be spline-coupled with a connecting hole 28b of the rotor 28 described later, and the rear end portion of the drive shaft 19 is also provided.
A spline portion and a screw portion are formed on 19b for attaching a pulley 34 for receiving a drive input. 22 indicates a shaft seal, 23 indicates a bearing
It is a C ring to prevent 21 from coming off.

A shaft chamber 24 is formed between the shaft hole of the housing 12 and the drive shaft 19, and the shaft chamber 24 is
While being communicated with the concave portion 14 and being sealed by the shaft seal 22, it is communicated with the housing side suction passage 15 through the seal drain hole. Inside the recess 14, a spring 25, a side plate 26, a cam ring 27 and a rotor are arranged in this order from the bottom.
28 is inserted.

The cam ring 27 has a cam surface composed of a small circular arc, a large circular arc, and a connecting curve between them, and the outer circumference thereof is the housing.
Non-rotatably coupled to the inner wall of the recess 14 of 12 via a pin,
A cam surface 27a is formed on the inner circumference thereof.

Then, a rotor 28 is inserted into the cam ring 27, the rotor 28 holds a plurality of vanes 29 in a radial direction so as to be retractable in the radial direction, and is introduced into a vane slot 28a provided on the base end side of the vane 29. Each vane 29 is urged radially outward by the pump discharge pressure, and the tip of each vane 29 is attached to the cam surface 27a of the cam ring 27 by this urging force.
Is abutted against. Further, the inner circumference of the rotor 28 is formed in a connecting hole 28b, spline-coupled with the drive shaft 19, and rotationally driven by the drive shaft 19.

On the side of these cam ring 27 and rotor 28, on the other hand,
The side plate 26 abuts, and the side plate 26 is pressed against the cam ring 27 and the rotor 28 by the pressure of the high pressure chamber 30 formed by the spring 25 and the side plate 26 and the recess 14, and on the other hand, the side plate 26 of the cover plate 13 There is a mounting surface. Therefore, the rotor 28, the cam ring 27, the side plate 26, and the cover plate 13 form a pump working space, which is partitioned by the vanes 29 to form a plurality of pump chambers 31.

Therefore, when the vane 29 slides in and out on the cam surface 27a of the cam ring 27 due to the rotation of the rotor 28, the volume of the pump chamber 31 is gradually increased and decreased to suck the working oil into the pump chamber 31 and suck the hydraulic oil into the pump chamber 31. Discharge from 31. A suction port 32 is provided in the cover plate 13 and the side plate 26 in a section where the pump chamber 31 increases in volume as the rotor 28 rotates (a suction port on the side plate side is not shown, but a port provided in the cam ring 27). The two are communicated with each other through the holes 27B and 27C), and the discharge port 33 is formed in the side plate 26 in a section where the volume of the pump chamber 31 decreases as the rotor 28 rotates. Reference numerals 35 and 36 are seal rings for maintaining the oil tightness of the high pressure chamber 30.

Here, in this embodiment, a section where the volume of the pump chamber 31 increases is a suction section A and a section where the volume of the pump chamber 31 decreases is a discharge section B, and two sections are formed respectively as shown in FIG. The discharge port 33 has an opening width reduced by 18 ° θ with respect to the rotation angle θ of the rotor 28, and the suction port 32 has an opening width enlarged by 18 ° θ. In other words, when the diameter passing through the circumferential center position of the small arc of the cam ring 27 indicated by the 90 ° -270 ° line in FIG. 2 is used as the reference line, the suction port 33 is the rotational direction of the rotor 28 from this reference line. The discharge port 33 is opened at a position of 18 ° to 90 °, and the discharge port 33 is also opened at a position of 126 ° to 162 °. Then, the section where the discharge port 33 and the suction port 32 are not formed, that is, the section where the hydraulic oil is confined between the end point of the suction section and the start point of the discharge section is a large arc closed section (first closed section). (Section) D, the end point of the discharge section and the start point of the suction section, a section small arc closed section (second closed section) d for confining the hydraulic oil is formed. The size of the discharge port 33 is equal to the interval between the two adjacent vanes 29, and the size of the suction port 32 is equal to the interval between the adjacent three vanes 29. Further, the size of the large arc closed section D and the small arc closed section d is formed to be equal to the interval between two adjacent vanes 29. Therefore, the number of pump chambers 31 is always constant in the suction section A and the discharge section B. Specifically, the cam surface 27a as shown in FIG.
The half-circle (θ = 0 to 180 °) is shown in a developed view, and the number of pump chambers 31 in the suction section A is three and the discharge section B is three.
There are two 31 pump rooms. The number of pump chambers 31 in these suction and discharge sections is kept constant by the above configuration.

Next, the operation will be described. When the rotor 28 is rotationally driven, the vane 29 slides on the cam surface 27a and sequentially moves the pump chamber 31 to repeatedly suck and discharge hydraulic oil, thereby exhibiting a function as a vane pump. .
At this time, the pressure fluctuation of the hydraulic oil in the suction section A and the discharge section B is caused by
The number of 31 is 3 and the number of pump chambers 31 in the discharge section B is always 2. Therefore, as shown in FIG. 4, the stepwise pressure fluctuation that has occurred each time the rotation angle θ of the rotor 28 advances by 18 ° is basically eliminated, and the rotor 28
Also, the pressing forces F and F'applied to the cam ring 27 are always balanced, the repetitive radial load is significantly reduced, and vibration is suppressed.

Assuming that the rotation angle θ of 0 ° (illustrated) is used as a reference as shown in FIG. 3, a small arc closing section d preceding the discharge port 33 in the discharge section B when the vane 29 is located at 0 °. Since the hydraulic oil pressure in the pump chamber 31 at is not facing the discharge port 33, the pressure is decreasing.
It is lower than the hydraulic oil pressure in the pump chamber 31 when it is advanced by 18 ° and + 18 °. As a result, slight fluctuations in the pressing forces F and F'applied to the rotor 28 and the cam ring 27 remain, but these fluctuations only occur each time the pump chamber 31 coincides with the small arc closing section d, and the rotor 28 Since it is generated 10 times for each rotation (every 36 ° advance), and is 1/2 compared to the conventional pressure fluctuation (20 times), noise reduction is realized by this.

Further, even if there is some deviation in the accuracy of the shape of the cam ring 27, the accuracy of the arrangement of the vanes 29 of the rotor 28, and the accuracy of assembly of the two, even if there is some phase deviation in the movement of the pump chamber 31 in the discharge section B, FIG. As indicated by F ', the fluctuation cycle of the pressure is 10 times / revolution, which is 1/2 of that in the conventional case, and the vibration is remarkably reduced.

Further, since the number of pump chambers 31 in the suction section A is always maintained at three chambers, there is no fluctuation in the amount of leaked oil as shown in FIG. Is basically reduced to a negligible level, and a stable supply of hydraulic oil is achieved.

As described above, the fluctuations of the pressing forces F and F'due to the hydraulic oil generated in the suction section A and the discharge section B due to the rotation of the rotor 28, the vibrations caused by the fluctuations, the noise related to the assembly accuracy, and the operation. The phenomenon such as pressure fluctuation of the oil itself is suppressed, and the vibration control and quietness of the vane pump 11 are improved.

(Effect) According to the present invention, since the openings of the suction section and the discharge section and the closing section between the suction section and the discharge section are machined to be an integral multiple of the interval of the vanes and positioned, the position section And the number of pump chambers in the discharge section is always constant,
It is possible to suppress the fluctuation of the pressing force due to the working fluid in the pump chamber, and to reduce the vibration, noise and pressure fluctuation of the working fluid due to this fluctuation. As a result, vibration control and quietness of the vane pump can be improved.

[Brief description of drawings]

1 to 5 are views showing an embodiment of a vane pump according to the present invention. FIG. 1 is a longitudinal sectional view of the vane pump, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. FIG. 4 is a 180 ° development view in the cam ring of FIG. 2, FIG. 4 is a view showing a change of pressing force with respect to its rotation angle, FIG. 5 is a view showing a change of leakage oil amount with respect to its rotation angle, and FIGS. FIG. 8 is a diagram showing a conventional vane pump, FIG. 6 is a sectional view of the inside of the cam ring, FIG. 7 is a diagram showing changes in pressing force with respect to its rotation angle, and FIG. 8 is a diagram showing the amount of leaked oil with respect to its rotation angle. It is a figure which shows change. 11 …… vane pump, 12 …… housing, 13 …… cover plate, 15 …… annular recess (cam ring housing), 26…
… Side plate, 27 …… Cam ring, 27a …… Cam surface, 28 …… Rotor, 29 …… Vane, 31 …… Pump chamber, 32
…… Inhalation port, 33 …… Discharge port.

Claims (1)

[Scope of utility model registration request] 1. A cam ring having a cam surface composed of a small arc and a large arc and a connecting curve between them, a housing forming a cam ring housing with a cover plate, and a cam surface housed in the cam ring housing. A side plate that holds 10 vanes that are in sliding contact with each other at equal intervals on the circumference, rotates the vanes by protruding and retracting in the radial direction, and a suction port and a discharge port that are arranged on the side of the cam ring. A pump chamber is formed by two adjacent vanes, a cam surface, a rotor outer peripheral surface, a cover plate and a side plate, and the volume of the pump chamber is changed with the rotation of the rotor to suck the working fluid. When the section where the volume of the pump chamber increases while the discharge is performed is the suction section and the section where the volume of the pump chamber decreases is the discharge section, these sections are divided into two parts. In the vane pump to be formed,
With the diameter passing through the circumferential center position of the small arc of the cam ring as a reference line, the suction port is opened from the reference line to a position of 18 ° to 90 ° in the rotation direction of the rotor, and the discharge port is A vane pump characterized in that the vane pump is opened at a position of 126 ° to 162 ° in a rotation direction of the rotor from a reference line.