JP2015004328A - Variable vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable vacuum pump in which its operated state can be changed into one state functioning as a pump and the other state not functioning as a pump but reducing operation load.SOLUTION: A variable vacuum pump includes a cylindrical housing 1 with a bottom part and a released end of the housing 1 is closed by a cover 2. A side plate 3 forming a pump chamber 5 between itself and a bottom part 4 is arranged inside the cover 2 of the housing 1. A diaphragm 12 is arranged between the cover 2 and the housing 1. A suction port 6 and a master buck are connected to a negative pressure path connecting part 13. The negative pressure path connecting part 13 and the inside part of the diaphragm 12 are connected by a negative pressure control path 14. When an inner pressure of the negative pressure path connecting part 13 is decreased down to a prescribed pressure, the diaphragm 12 is operated, the side plate 3 is released from a vane in the pump chamber 5, a pump function of the variable vacuum pump is stopped and then a load by the vacuum pump is reduced.

Description

  The present invention relates to a variable vacuum pump that maintains an operating state while a driving source is in operation, regardless of whether a vacuum is required.

  In an automatic brake booster (brake master back), the intake pipe pressure is often used in the case of a gasoline engine in which a strong negative pressure is generated in the intake manifold ahead of the throttle body by the throttle valve. A vacuum pump is used in a diesel engine whose intake pipe pressure is lower than that of a gasoline engine because of the structure without a throttle valve. Moreover, even if it is a gasoline engine, the motor vehicle which uses a vacuum pump is known. Electric vehicles also use vacuum pumps.

  This vacuum pump is known to be connected to a member that rotates when the engine is operated, such as an engine camshaft. For example, the vacuum pump continues to suck air from the brake master back while the engine is operating. It becomes. Also in an electric vehicle, a vacuum pump may be connected to a traveling motor, and the vacuum pump continues to suck air while the motor is operating.

  In the brake master back, air pressure (negative pressure) is maintained by the check valve. If the brake master back reaches the predetermined negative pressure and the brake is not used, the negative pressure is maintained. Therefore, suction by the vacuum pump is not always required, but as the vacuum pump continues to operate as described above, the drive load of the vacuum pump on the engine continues even when suction by the vacuum pump is not required As a result, the fuel consumption of the engine may be reduced.

  Therefore, in the vane pump as a vacuum pump, in order to maintain the airtightness of each space partitioned by the vanes in the pump chamber, a side plate (side panel) arranged to have a predetermined clearance with respect to the vanes, When vacuum performance is not required, move away from the vane so as to widen the clearance between the vanes, and communicate with the spaces separated by the vanes in the pump chamber so that the internal pressure of each space is the same. Therefore, it has been proposed to reduce the driving load (see, for example, Patent Document 1).

  That is, when the negative pressure is not required, the side plate is moved away from the vane as described above, and when the negative pressure is required, the side plate is moved closer to the vane. The driving load when the negative pressure is not required can be reduced as compared with the case where the negative pressure is required.

  In Patent Document 1, a negative pressure chamber is provided on the opposite side of the pump chamber with respect to one side plate of the pump chamber, and the side plate can move to the negative pressure chamber side so as to leave the vane in a state where the pump chamber is sealed. It is said. Further, the side plate is biased toward the pump chamber, and is normally arranged with a predetermined clearance with respect to the vane, and can function as a normal vane pump.

  Also, the pump chamber is connected to the master back so that air is sucked from the master back, and the negative pressure chamber is also connected to the master back, and the state that communicates with the outside air and the state that communicates with the master back are switched by the switching valve, respectively. It is supposed to be. Thus, by switching between the two switching valves, the normal pump chamber has a negative pressure and the negative pressure chamber has become atmospheric pressure, and the negative pressure chamber has a negative pressure and the pump chamber has become atmospheric pressure. Can be switched. When the negative pressure chamber is set to a negative pressure, the side plate moves to the negative pressure chamber side by the air pressure, moves away from the vane as described above, and the operating load of the vane pump decreases. Patent Document 1 describes a configuration using a seal and a configuration using a diaphragm as a configuration for the side plate to move while the pump chamber is sealed.

JP 2010-18085 A

  By the way, in the vane pump of patent document 1, although air pressure is used for the movement of a side plate, it changes to the state which is functioning as a normal pump, and the state where the drive load became low without functioning as a pump. Two switching valves are used, and an actuator is required to switch the switching valve.

  In addition, since the vane pump, which is basically not electronically controlled because it is connected to the engine camshaft or the like, requires electronic control for the operation of the actuator, the structure becomes complicated. At this time, the switching valve is switched based on the pressure of the surge tank attached to the master back, and the two switching valves are not switched at the same time, but are switched with a time difference. This will increase costs.

  The present invention has been made in view of the above circumstances, and provides a variable vacuum pump that can be changed between a state that functions as a pump and a state in which an operation load is reduced without functioning as a pump. For the purpose.

In order to achieve the above object, the variable vacuum pump of the present invention comprises:
A substantially bottomed cylindrical housing;
A cover for closing the open end of the housing;
A side plate that is disposed inside the cover, forms a pump chamber with the bottom of the housing, and is movable along the axial direction of the housing;
A rotating body that divides the pump chamber into a plurality of spaces and reduces and increases the volume of the space by rotating around a rotation axis parallel to the axial direction of the housing;
An intake port and an exhaust port connected to the pump chamber;
A negative pressure path connecting a master back to the inlet;
A check valve that regulates the flow of gas from the pump chamber to the negative pressure path;
A diaphragm provided between the cover and the side plate, connected to the side plate, for moving the side plate;
A negative pressure control path for communicating the space in the diaphragm and the negative pressure path in order to operate the diaphragm;
A separation position in which the side plate holds each space separated by the rotating body in the pump chamber in a separated state; and a communication position in which the side plate leaves the rotating body and communicates each space. It can be moved between
The diaphragm moves the side plate between the separation position and the communication position based on an internal pressure of the negative pressure path communicated by the negative pressure connection path.

According to such a configuration, when the pressure on the master-back side is high, that is, when the pressure in the negative pressure path is high, the diaphragm does not operate and becomes a convex state, and the side plate connected to the diaphragm is In the separation position. As a result, a plurality of spaces in which the volume is increased and decreased are separated by a rotating body in the pump chamber, and the variable vacuum pump is in a state of sucking air from the master back. At this time, a relatively large load acts on the drive shaft side due to the decrease and increase of the internal pressure of the spaces separated from each other based on the increase and decrease of the volume of the space described above.
On the other hand, when the pressure on the master back side decreases, the pressure in the negative pressure path also decreases. As a result, the pressure in the negative pressure control path also decreases, and when the inner pressure of the diaphragm becomes equal to or lower than the predetermined pressure, the side plate is attracted to the operated diaphragm and moves from the separation position to the communication position side.

As a result, the spaces partitioned by the rotating body in the pump chamber communicate with each other, and even if the volume of each space increases or decreases, the internal pressure of the space does not change and the rotational load of the rotating body decreases. Will do. Therefore, even if the pump continues to operate regardless of the internal pressure of the master back, the diaphragm operates when the negative pressure of the master back, that is, the negative pressure in the negative pressure path reaches a sufficient level. Therefore, in a state where the negative pressure of the master-back is sufficient and the variable vacuum pump does not need to operate, the spaces partitioned by the rotating body of the pump chamber communicate with each other, and the volume of each space increases and decreases. The associated expansion and compression of air is eliminated and the operating load of the pump is reduced.
As a result, when the drive shaft of the pump is connected to the drive engine or motor side of a device such as an automobile and rotates, the load on the engine or motor is reduced, improving fuel efficiency and reducing power consumption. Can be planned.

Moreover, when the pressure in the negative pressure path increases, the diaphragm returns to the original state, so that the side plate returns to the separation position, and the variable vacuum pump functions as a pump. Decrease.
Such movement of the side plate is controlled only by characteristics such as the material and shape of the diaphragm and a change in the negative pressure of the negative pressure path. Therefore, to control the movement of the side plate, an electric actuator or electric There is no need for a solenoid or the like, and there is no need to provide a control device for controlling these electric members, and the variable vacuum pump can have a very simple configuration.
The cross-sectional shape of the inner periphery of the cross-section of the substantially bottomed cylindrical housing may be circular or elliptical.

  The said structure of this invention WHEREIN: It is preferable that the orifice is provided in the said negative pressure control path | route.

  According to such a configuration, by providing the orifice, the flow rate of air in the negative pressure control path is limited, and even if a sudden pressure fluctuation occurs in the negative pressure path, the diaphragm is prevented from moving rapidly. The side plate can be reliably moved away from the separation position or returned by the diaphragm.

  ADVANTAGE OF THE INVENTION According to this invention, while sucking air from the master back | bag as a booster apparatus, such as a motor vehicle, when the master back | bag is a sufficient negative pressure, a side plate can be separated and the load to drive sources, such as an engine, can be reduced In the vacuum pump, an electric actuator is not required, and thus a simple configuration that does not require a control device can be achieved. In addition, this makes it possible to reduce the cost of the variable vacuum pump.

It is a front view which shows the variable vacuum pump of embodiment of this invention. It is a principal part schematic diagram which shows the vane and rotor in a variable vacuum pump. It is principal part sectional drawing which shows the said variable vacuum pump which has a side plate in a separation position. It is principal part sectional drawing which shows the said variable vacuum pump which has a side plate in a communicating position. It is a figure which shows a side plate, Comprising: (a) is a front view, (b) is a side view of a long diameter side, (c) is a side view of a short diameter side, (d) is sectional drawing. is there.

Embodiments of the present invention will be described below.
As shown in FIG. 1 to FIG. 5, the variable vacuum pump of this embodiment is a vane pump, which is used in, for example, an automobile, and includes a drive shaft connected to an engine. A rotor 10 and a vane 9 described later connected so as to rotate integrally rotate.

  The variable vacuum pump is connected to the master back of the brake booster and is used to make the master back a predetermined air pressure (negative pressure).

The variable vacuum pump includes a substantially bottomed cylindrical housing 1, and a cover 2 is attached to the open end of the housing 1 to close the opening on the open end side of the housing 1. In this embodiment, the cross section of the inner peripheral surface of the housing 1 is not a circle but an ellipse. The cross-sectional shape of the inner peripheral surface of the housing 1 may be a circle or an ellipse.
A side plate (variable plate) 3 is attached to the open end side of the housing 1 and inside the cover 2. The side plate 3 constitutes a pump chamber 5 between the housing 1 and the bottom 4 of the housing 1. The housing 1 is provided with an intake port 6 for sucking gas into the pump chamber 5 and an exhaust port (discharge port) 7 for discharging the gas in the pump chamber 5. The intake port 6 is provided with a negative pressure control path 14 connected to a negative pressure path connection portion 13 which is connected to a negative pressure path connecting the intake port 6 and the master back and becomes a part of the negative pressure path. A check valve 15 is provided between the negative pressure path connecting portion 13 and the intake port 6. The check valve 15 restricts the flow of air from the pump chamber 5 to the negative pressure path side.

  An inner peripheral surface of a cylindrical (elliptical cylinder) portion of the housing 1 is a cam surface 8, and top vanes 9 b provided at both ends of a vane 9 (main vane 9 a) described later slide on the cam surface 8. It is supposed to be. Inside the substantially cylindrical pump chamber 5, a rotor 10 having a rotation axis parallel to the axial direction of the housing 1 is arranged at a position eccentric from the axis of the substantially cylindrical cam surface 8 (pump chamber 5). ing. That is, the rotor 10 is arranged eccentrically with respect to the axial center position of the cam surface 8 so that the outer peripheral surface thereof is substantially in contact with the cam surface 8 (the inner peripheral surface of the housing 1) at one point.

  The base end portion 10 b of the rotor 10 is rotatably supported by a bearing 11 provided on the bottom portion 4 of the housing 1. The central axis of rotation of the rotor 10 is parallel to the axial direction of the housing 1 (the axial direction of the cam surface 8). The bearing 11 is provided so as to protrude from the outer surface of the bottom portion 4 opposite to the pump chamber 5, and the base end portion 10 b of the rotor 10 is rotated by the bearing 11 provided in the housing 1 while penetrating the bottom portion 4. It is supported freely.

  The main body portion 10a disposed in the pump chamber 5 of the rotor 10 is formed in a cylindrical shape, and grooves are provided at two locations along the diameter direction, and the vanes 9 are inserted into the grooves to move the rotor 10 in the diameter direction. It is in a state of penetrating along. Further, the vane 9 is movable in the length direction of the vane 9, that is, in the diameter direction of the rotor 10 while penetrating the rotor 10.

  As shown in FIG. 2, top vanes 9 b are attached to both ends of the main vane 9 a that is the main body of the vane 9, and the top vanes 9 b are in contact with the cam surface 8 on the inner periphery of the housing 1. Become. When the vane 9 rotates with the rotation of the rotor 10, the top vane 9 b slides with respect to the cam surface 8. The inside of the pump chamber 5 is separated into the left and right spaces of the vane 9 by the vane 9.

  When the rotor 10 rotates, the vane 9 rotates while moving in the diameter direction with respect to the rotor 10 because the rotor 10 is in an eccentric position with respect to the pump chamber 5 having an elliptical cross section (substantially circular). It will be. When the volume of the space on the one side surface of the separated vane 9 decreases due to the rotation of the vane 9, the volume of the space on the other side surface increases, and then the volume of the space on the other side surface whose volume has increased. Decreases, and the volume of the space on one side where the volume is reduced increases. The volume of each space is repeatedly increased and decreased. At this time, the increase and decrease of the internal pressure are repeated in each space. As a result, gas is sucked from the intake port 6 and gas is discharged from the exhaust port 7.

  In the variable vacuum pump as the vane pump, the cam surface 8 which is the inner peripheral surface of the pump chamber 5 is extended along the axial direction of the housing 1 on the open end side of the above-described bottomed substantially cylindrical housing 1. It has become. Accordingly, the position of the side plate 3 in the state of functioning as a vane pump as described above, that is, the position where the side edge of the vane 9 on the side plate 3 side is substantially in contact with the side plate 3 is substantially on the opposite side of the pump chamber 5. The housing 1 having a cylindrical inner peripheral surface has a slightly extended shape. The side plate 3 is movable along the axial direction of the housing 1 and the rotor 10 at an extended portion of the housing 1.

  As shown in FIG. 5, an annular seal 17 is fitted around the side plate 3 in a seal groove 3 b provided on the outer periphery of the side plate 3, and between the outer periphery of the side plate 3 and the cam surface 8. Is sealed. By this seal 17, the space between the side plate 3 and the cam surface 8 which is the inner peripheral surface of the pump chamber 5 is hermetically sealed. In addition, a fitting hole 3a is provided at the center of the side plate 3 to which a fitting protrusion 12a at the center of a diaphragm 12 described later is connected. The fitting hole 3a is closed by the fitting protrusion 12a.

The extended portion of the housing 1 is between the cover 2 of the housing 1 and the side plate 3 at a position where gas can be sucked and discharged as described above.
A diaphragm 12 for moving the side plate 3 is provided between the cover 2 and the side plate 3 at the extended portion. The diaphragm 12 is held in a state where the entire peripheral edge is sandwiched between the peripheral edge of the cover 2 and the outer peripheral portion of the housing 1, and the diaphragm 12 is interposed between the side plate 3 and the cover 2. It is in a state of being airtightly separated at 12 positions.

  The diaphragm 12 has a convex shape toward the side plate 3, and a fitting protrusion 12 a at the center thereof is fitted in a fitting hole 3 a provided at the center of the side plate 3. The fitting protrusion 12a does not protrude toward the pump chamber 5 side of the side plate 3 in the state of being fitted into the fitting hole 3a. The surface of 12a on the pump chamber 5 side is disposed in substantially the same plane, and these surfaces are substantially flush.

  The space between the diaphragm 12 and the cover 2 is connected to a pipe which is a negative pressure control path 14. When air is exhausted through the negative pressure control path 14 and the internal pressure becomes a predetermined pressure or less, the diaphragm 12 is negative. The side plate 3 is recessed so as to be crushed by pressure, and can be moved in a direction in which the side plate 3 connected to the fitting protrusion 12a is pulled away from the vane 9 and the rotor 10.

  The negative pressure control path 14 has one end passing through the cover 2 and connected to the space on the cover 2 side of the diaphragm 12, and the other end connected to the negative pressure path connecting portion 13. . The negative pressure control path 14 is disposed on the master back side (tip side) from the check valve 15 of the negative pressure path connection portion 13. Further, the negative pressure control path 14 is provided with an orifice 16 for narrowing the path. For example, after the internal pressure on the negative pressure path connecting portion 13 side becomes a predetermined pressure for operating the diaphragm 12, the diaphragm 12 is delayed a little. The internal pressure becomes a predetermined pressure.

  In the variable vacuum pump having such a configuration, when the engine is started in a state where the internal pressure of the master back does not reach a predetermined internal pressure (negative pressure), the side plate 3 is brought into a separation position where the side plate 3 substantially contacts the vane 9 and the rotor 10. is there. In this state, the rotor 10 rotates and the vane 9 rotates in response to the rotation of the drive shaft coupled to the engine.

  At this time, the spaces separated by the vanes 9 in the pump chamber 5 are separated without communicating with each other, and the variable vacuum pump functions as a vacuum pump, and gas (air) from the master back. , And the internal pressure in the master bag is lowered to finally become a set pressure. In a state in which the variable vacuum pump is sucking air from the master back, the internal pressure on the variable vacuum pump side is lower than the negative pressure path connecting portion 13, and the check valve 15 is open.

  When the internal pressure of the master back reaches a predetermined pressure by continuing to drive the engine, the inside of the diaphragm 12 becomes the operating pressure of the diaphragm 12 through the negative pressure control path 14 connected to the diaphragm 12 from the negative pressure path connecting portion 13. Thereby, the diaphragm 12 will be dented in the cover 2 side. Corresponding to the operation of the diaphragm 12, the side plate 3 connected to the diaphragm 12 moves from the separation position (shown in FIG. 3) to the communication position on the cover 2 side (shown in FIG. 4).

  When the internal pressure of the master back is lowered to a predetermined pressure, the internal pressure of the negative pressure path connecting portion 13 and the internal pressure of the pump chamber 5 are substantially equal. For example, the internal pressure of the pump chamber 5 is slightly lower. At this time, the internal pressure of the negative pressure path connecting portion 13, the internal pressure of the negative pressure control path 14, and the internal pressure on the cover 2 side of the diaphragm 12 are substantially equal. Further, the diaphragm 12 and the side plate 3 are separated from the pump chamber 5 by the side plate 3 in an airtight manner, and are separated from the space on the cover 2 side by the diaphragm 12. For example, the diaphragm 12 is recessed. There is no atmospheric pressure.

  Therefore, when the air in the space on the cover 2 side of the diaphragm 12 is sucked from the negative pressure control path 14 and the diaphragm 12 is deformed to have a concave internal pressure, the diaphragm 12 is activated. When the diaphragm 12 is operated and the side plate 3 is pulled away from the vane 9 and the rotor 10, the spaces separated by the vanes 9 in the pump chamber 5 communicate with each other. Thereby, even if the volume of the space separated into the vanes 9 decreases or increases, the internal pressure does not increase or decrease because the spaces communicate with each other. Thereby, the rotational load (rotational torque) of the vane 9 and the rotor 10 decreases. When the diaphragm 12 is deformed and recessed as shown in FIG. 4, a gap 3 c is formed between the side plate 3 and the vane 9.

  In this state, since the variable vacuum pump is not functioning, the internal pressure of the pump chamber 5 becomes higher than the negative pressure path connecting portion 13, and the check valve 15 is closed. Therefore, although the variable vacuum pump is idling, even if the internal pressure of the pump chamber 5 rises due to leakage from the exhaust port 7 or the like, the internal pressure of the negative pressure path connecting portion 13 is kept low by the check valve 15. The Therefore, when the variable vacuum pump stops functioning, the internal pressure of the diaphragm 12 connected to the negative pressure path connecting portion 13 via the negative pressure control path 14 is maintained at a low state, and the side plate 3 returns to the original state. There is no.

  When the internal pressure of the master back starts to increase due to the start of use of the brake or the like, the internal pressure of the negative pressure path connection portion 13 increases, thereby increasing the internal pressure of the negative pressure control path 14 and increasing the internal pressure of the diaphragm 12. The diaphragm 12 whose internal pressure is increased returns from the recessed state to the original state, and the side plate 3 is returned from the communication position (position of the side plate in FIG. 4) to the separation position (position of the side plate in FIG. 3). Become.

  The operation and return timing of the diaphragm 12 can be adjusted by the thickness, shape and material of the diaphragm 12, the shape such as the diameter of the negative pressure control path 14, and the shape such as the diameter of the orifice 16. Thereby, for example, it can be prevented that the operation of the diaphragm 12 is too slow or the return is too late and the internal pressure of the master back cannot be properly controlled.

  From the above, the variable vacuum pump does not require an actuator such as a switching valve, and does not require a control device for controlling the actuator, and only by changing the internal pressure of the negative pressure path connecting portion 13 or the like, When it is necessary to lower the internal pressure, the side plate 3 is made to function as a pump as a separation position. When the internal pressure of the master-back is sufficiently low and it is not necessary to reduce the internal pressure of the master back, the side plate 3 is moved to the communication position. The load of the variable vacuum pump can be reduced by moving and making the variable vacuum pump not function as a pump.

The vane pump as the variable vacuum pump is not limited to a pump having only one vane in this embodiment. For example, the vane pump may have a plurality of vanes, and the present invention can be applied to various vane pumps. Applicable.
Further, the present invention can be applied to any rotary type pump other than the vane pump as long as the volume of the space in which the pump chamber is separated by the rotating body is increased or decreased. For example, the present invention can be applied to a rotary pump or a gear pump. The invention can be applied.

DESCRIPTION OF SYMBOLS 1 Housing 2 Cover 3 Side plate 4 Bottom part 5 Pump chamber 6 Intake port 7 Exhaust port 8 Cam surface 9 Vane (rotating body)
10 Rotor (Rotating body)
12 Diaphragm 13 Negative pressure path connection (negative pressure path)
14 Negative pressure control path 15 Check valve 16 Orifice

Claims (2)

A substantially bottomed cylindrical housing;
A cover for closing the open end of the housing;
A side plate that is disposed inside the cover, forms a pump chamber with the bottom of the housing, and is movable along the axial direction of the housing;
A rotating body that divides the pump chamber into a plurality of spaces and reduces and increases the volume of the space by rotating around a rotation axis parallel to the axial direction of the housing;
An intake port and an exhaust port connected to the pump chamber;
A negative pressure path connecting a master back to the inlet;
A check valve that regulates the flow of gas from the pump chamber to the negative pressure path;
A diaphragm provided between the cover and the side plate, connected to the side plate, for moving the side plate;
A negative pressure control path for communicating the space in the diaphragm and the negative pressure path in order to operate the diaphragm;
A separation position in which the side plate holds each space separated by the rotating body in the pump chamber in a separated state; and a communication position in which the side plate leaves the rotating body and communicates each space. It can be moved between
The variable vacuum pump, wherein the side plate is moved between the separation position and the communication position based on an internal pressure of the negative pressure path through which the diaphragm is communicated by the negative pressure connection path.   The variable vacuum pump according to claim 1, wherein an orifice is provided in the negative pressure control path.

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