JP5521626B2 - Control device for variable displacement vane pump - Google Patents

Description

  The present invention relates to a control device for a variable displacement vane pump, and more particularly to a pressure and flow rate control device.

  Conventionally, a variable displacement vane pump driven by an electric motor is used as a hydraulic power source of a machine tool. The variable displacement vane pump works on the inner diameter side of the cam ring and compensates for the pressure by balancing the oil pressure proportional to the discharge pressure with the spring force placed at the opposite position. The pressure is applied by a piston, and the pressure is compensated by balancing with a control cylinder driven by a counter spring force or a pressure controlled by a pressure compensation control valve (compensator).

  Hydraulic pumps for machine tools are generally used at low pressures of 7 MPa or less, and are used for holding pressure such as clamps and chucks, so the time that the pump is discharging oil is extremely short, and the maximum pump output The value was usually about 150 to 200% of the output of the motor to be driven.

  However, the output torque of such a pump is determined by the discharge pressure-flow rate characteristic, and in the constant discharge type characteristic as shown by the dotted line 60 in FIG. 5, the motor output is determined in order to suppress it within 150-200% of the motor output. For this reason, an electric motor having a larger output than the output in a state where pressure is actually held has to be selected. For this reason, most of the usage state is used in a state where the load factor of the electric motor is low. Therefore, in an electric motor with improved efficiency in the vicinity of the 100% load factor, it must be used in a portion with low efficiency, resulting in a loss. It was getting bigger.

  In order to reduce this loss and to provide a compact and low-cost variable displacement vane pump for machine tools, in Patent Document 1, springs with different elastic forces are installed in series on the coaxial line, and the cam ring is always in contact with one end. A constant horsepower type characteristic as shown by a solid line 61 in FIG. 5 is obtained by applying the elastic force of the spring to the plunger to change the discharge amount stepwise. Further, in Patent Document 2, a cylinder that houses two different springs and a piston that gives a cam ring a force in the same direction as the repulsive force of the spring is provided, and oil is introduced into the cylinder through a sequence valve from the discharge pressure side of the pump. Then, when the pressure reaches the set pressure of the sequence valve, the cylinder pressure is released to the tank, and a constant horsepower type characteristic is obtained in which full cutoff is achieved.

  On the other hand, the variable displacement vane pump disclosed in Patent Document 3 is not a constant horsepower control, and controls the maximum discharge amount even when the rotation speed increases. It arrange | positions concentrically and it enables it to adjust each pressure for low pressure and high pressure from the outside by making a pressure adjustment screw act on each spring.

Japanese Utility Model Publication No. 48-9203 JP 55-66685 A Japanese Patent Publication No.46-23691

  In Patent Document 1, low pressure and large capacity, that is, adjustment of the pump maximum discharge amount (reference numeral 41 in FIG. 5) is the maximum flow rate adjusting screw provided on one side of the cam ring, and adjustment of maximum pressure (reference numeral 42 in FIG. 5) is the cam ring. It can be controlled with a pressure adjusting screw that is sandwiched and opposed. However, the low pressure adjustment (43 in FIG. 5) with constant horsepower characteristics and the flow rate adjustment in the high pressure range are determined by the part shape and dimensions of the selected spring and the like, and cannot be adjusted from the outside. Moreover, in the thing of patent document 2, this point is neither disclosed nor suggested. Furthermore, the flow rate adjustment in the high pressure range is because these inventions do not have a means to absorb the variation of the component dimensions in the vane pump that controls the capacity with an extremely small eccentric amount. There was a lack of mass productivity, such as the need to correct the characteristics of. In addition, when the power supply frequency is different, there is a problem that the maximum pressure must be lower in the 60HZ region than in the 50HZ region.

  Therefore, as in Patent Document 3, it can be considered that each spring can be adjusted from the outside. However, even if low pressure adjustment can be performed from the outside, flow rate adjustment is still not possible, so mass productivity is lacking, and appropriate discharge amount and maximum pressure adjustment that match the efficiency of the motor in the high pressure range cannot be performed. .

  In view of such problems, the problem of the present invention is that the flow rate adjustment of the variable displacement vane pump in the high pressure range is easy and high in mass productivity, and further, the motor efficiency is effective even if the rotation speed is different due to the difference in power supply frequency. It is to provide a control device for a variable displacement vane pump that can be utilized in the future.

  In the present invention, in the control device for the pressure and flow rate of the variable displacement vane pump configured to change the eccentric amount of the cam ring having a square cross section according to the load pressure and discharge the discharge amount necessary for the operation, A maximum flow rate adjusting portion that regulates a maximum eccentric amount; and the maximum flow rate adjusting portion is provided on the opposite side across the cam ring, and a low pressure spring that biases the cam ring; and the low pressure spring is inserted to the cam ring side A holder having a contact surface; a high-pressure spring that urges the holder toward the cam ring; a pressure adjusting unit that adjusts the high-pressure spring force; and a cam ring of the holder that contacts the cam ring-side contact surface A sleeve for restricting movement in the direction, and the holder has the cam ring side contact surface within the allowable eccentricity of the cam ring. And either leave or the cam ring being in selectively abut, by the cam ring position of the sleeve to provide a control device for a variable displacement vane pump which is adjustable, to solve the aforementioned problems.

  That is, the cam ring side contact surface of the holder urged to the cam ring side by the high pressure spring can be selectively contacted with either the sleeve or the cam ring within the allowable eccentricity of the cam ring. It is controlled by a spring for high pressure, and is controlled by a spring for high pressure at high pressure. In the present invention, since the position of the sleeve with which the cam ring side contact surface of the holder contacts can be adjusted, the amount of movement of the cam ring when the cam ring changes from the low pressure region to the high pressure region can be adjusted.

  The holder may be inserted with a low pressure spring, and may be sandwiched between the low pressure spring and the high pressure spring. Further, similarly to FIG. 1 of the cited document 3, the low-pressure spring may be adjusted from the outside by a screw mechanism in which the tip abuts against the low-pressure spring and penetrates the holder and the inside of the high-pressure spring.

According to a second aspect of the present invention, the holder holds the anti-cam ring side of the low-pressure spring, the low-pressure spring contacts the cam ring via a plunger, and the sleeve is attached to the tip. A cylindrical shape having a reduced diameter portion, screwed to the pump body toward the cam ring, and the low pressure spring abuts the cam ring through the plunger through the through hole of the reduced diameter portion. cage, the cam ring side contact surface of the holder has a control device for a variable displacement vane pump which is to be selectively abut in a counter cam ring side of the counter-cam ring side or the plunger of the reduced diameter portion.

  Since the contact surface of the holder is in contact with the sleeve via the plunger rather than directly with the cam ring, it is easy to adjust and the processing and assembly accuracy can be improved.

According to a third aspect of the present invention, the holder has a cylindrical shape having a flange at one end and a bottom at the other end, and an outer diameter of the cylindrical portion is smaller than the inner diameter of the high-pressure spring, and the holder for the low-pressure is provided in the cylinder. A control device for a variable displacement vane pump in which a part or all of the spring is inserted and the flange is configured to be able to abut on the side opposite to the cam ring of the reduced diameter portion of the sleeve.

  Low pressure springs are rarely adjusted for use. Therefore, the components and the structure are simplified by being installed in the cylindrical holder.

  According to a fourth aspect of the present invention, the sleeve has a cylindrical shape with a male screw provided on the outer periphery thereof, one end having the reduced diameter portion having the through hole, and the other end having an outer screw hole. Control of a variable displacement vane pump having a reduced diameter portion, a cylindrical middle portion of the sleeve being joined by welding, and a pressure adjusting screw of the pressure adjusting portion being screwed into the screw hole The device.

  Since the sleeve is closed at the diameter-reduced portions on both sides, it is difficult to process and the number of parts increases. Therefore, the number of parts is reduced by joining the middle part of the cylindrical part by welding.

  According to the present invention, by adjusting the position of the sleeve with which the cam ring side contact surface of the holder contacts, the moving position of the cam ring when changing from the low pressure region to the high pressure region can be adjusted. It has become possible. In addition, since it can be adjusted externally, flow rate adjustment is easy and mass productivity is high.Furthermore, the high-pressure side flow rate can be adjusted even when there is a difference in power supply frequency at the place of use, and handling is easy to adjust. The variable displacement vane pump control device can effectively use the motor efficiency according to the situation.

  In the second aspect of the present invention, the holder is separated from the sleeve via the plunger, is easily adjusted, and the processing and assembly accuracy can be improved, so that the mass productivity is high. Since the sleeve is screwed to the main body and the cam ring side contact surface of the holder is selectively brought into contact with the reduced diameter portion or plunger of the sleeve within the sleeve, the structure is simple and the assembly is easy.

  In the invention according to claim 3, the holder has a bottomed cylindrical shape with a flange, is provided inside the high-pressure spring, and further, the low-pressure spring is inserted to simplify the parts and structure. The amount of protrusion from the main body of the control unit of the mold vane pump was reduced.

  Furthermore, in the invention described in claim 4, since the intermediate portion of the cylindrical portion of the sleeve is joined by welding to reduce the number of parts, management and structure are easy. As described above, according to the present invention, the processing variation of parts can be easily adjusted at the factory shipment stage, the inspection time in shipping inspection, the time for disassembly and assembly for adjustment can be shortened, Therefore, it is possible to provide an energy-saving pump at low cost.

It is a longitudinal cross-sectional view which shows 1st embodiment of the control apparatus of the variable displacement vane pump of this invention. It is a longitudinal cross-sectional view which shows 2nd embodiment of the control apparatus of the variable displacement type vane pump of this invention. It is a longitudinal cross-sectional view which shows 3rd embodiment of the control apparatus of the variable displacement vane pump of this invention. (A) of the variable displacement vane pump of this invention is a figure which shows discharge pressure-flow characteristic, (b) is a characteristic figure which shows the relationship between discharge pressure and shaft input. (A) of the conventional variable displacement vane pump is a figure which shows a discharge pressure-flow rate characteristic, (b) is a characteristic figure which shows the relationship between discharge pressure and shaft input.

  A first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, a variable displacement vane pump 1 of the present invention is configured to be able to enter and exit from a pump body 2, a rotor 3 pivotally supported by the pump body and provided with vane grooves 3a radially, and a vane groove of the rotor. A plurality of vanes 4 and a cam ring 5 having a quadrangular cross section in which the plurality of vanes are in sliding contact with the inner diameter side 5a are provided. Then, the amount of eccentricity e of the cam ring 5 with respect to the rotor 3 is changed in accordance with the load pressure to discharge a discharge amount necessary for operation. A maximum flow rate adjusting portion 6 for restricting the maximum eccentric amount of the cam ring 5 is provided on the right side in the figure of the main body 2, and the right end of the cam ring is shown in the right direction by the tip 6 b of the screw 6 a screwed to the main body 2. It is supposed to regulate movement to. The screw 6a is fixed to the main body by a lock nut 6c. As shown in the figure, the upper part of the cam ring 5 is provided with a screw 7 for adjusting the height of the cam ring and adjusting the behavior in the eccentric direction. Since the structure and principle of such a variable displacement vane pump are the same as in the prior art, the description thereof is omitted.

  In the first embodiment of the present invention, the cylindrical sleeve 12 is screwed to the female screw 2a of the main body 2 by the male screw 12a provided on the outer periphery on the opposite side to the maximum flow rate adjusting unit 6, and the main body is fixed by the lock nut 15. It is fixed to. A reduced diameter portion 12c having a through hole 12b is provided at the tip of the sleeve. A lid 12e having a screw hole 12d is screwed to the other end of the sleeve to form an outer reduced diameter portion 12h. A pressure adjusting screw 13 is provided in the screw hole 12d. A pressure adjusting screw receiver (piston) 14 with which the tip 13a of the pressure adjusting screw 13 abuts is provided in the sleeve 12 so as to be able to seal and slide with the sleeve inner diameter 12f. Further, a high-pressure spring 11 and a flange 10a of the holder 10 are provided in this order. The outer diameter of the flange is larger than the inner diameter of the through hole 12b. The piston 14, the high pressure spring 11, and the flange 10a are sandwiched between the pressure adjusting screw 13 and the reduced diameter portion 12c, and the cam ring side contact surface 10c of the flange. Is biased so as to be able to come into contact with the anti-cam ring side surface 12g of the reduced diameter portion 12c.

  The holder 10 having the flange 10a at one end has a bottomed cylindrical shape having a bottom 10b at the other end. The outer diameter 10d of the cylinder is smaller than the inner diameter of the high-pressure spring 11, and is used for high pressure in contact with the flange 10a. The spring is extrapolated. Further, a low pressure spring 9 is housed inside the cylindrical portion of the holder 10, and the anti-cam ring side surface 9 b of the low pressure spring is in contact therewith. The plunger 8 is in contact with the cam ring side surface 9 a of the low pressure spring, and the plunger is in contact with the cam ring 5. The plunger 8 has a stepped cylindrical shape composed of an abutting cylindrical portion 8a whose end abuts against the cam ring, a flange portion 8b, and a small diameter portion 8c. A low-pressure spring 9 is externally mounted on the small-diameter portion 8c, and the cam ring side surface 9a of the low-pressure spring is in contact with the opposite cam ring side surface 8e of the flange portion 8b. The outer diameter 8d of the flange portion 8e is smaller than the diameter of the through hole 12b of the sleeve 12, and is smaller than the outer diameter 10e of the flange 10a of the holder 10 and larger than the inner diameter 10f.

  Therefore, at the time of maximum discharge or no load, the high pressure spring 11 is stronger than the low pressure spring 9, so that the holder collar 10a abuts against the anti-cam ring side surface 12g of the reduced diameter portion 12c, and the cam ring 5 is only a low pressure spring. It is energized at. On the other hand, in the high pressure region, the cam ring 5 overcomes the force of the low pressure spring 9 and directly contacts the flange portion 8b of the plunger 8 with the flange 10a of the holder 10 and acts on the high pressure spring 11 through the holder, and the pressure is applied by the high pressure spring. Control is performed. The distance St between the anti-cam ring side surface 12g of the reduced diameter portion 12c of the sleeve and the anti-cam ring side surface 8e of the flange portion 8b of the plunger 8 is adjusted to be smaller than the eccentric amount e of the cam ring. The distance St can be adjusted by the screwing amount of the sleeve 12.

  Thereby, the holder 10 is within the allowable eccentricity e of the cam ring 5 (on the cam ring side contact surface 10c of the holder collar 10a) or the sleeve 12 (on the opposite cam ring side surface 12g of the reduced diameter portion 12c) or (through the plunger 8). It can be selectively brought into contact with any one of the cam rings 5.

  The pressure flow characteristics of the variable displacement vane pump will be described. The pump characteristics are a pressure flow characteristic and a pressure shaft input characteristic as shown by a solid line 50 in FIGS. 4 and 5 (a) and a solid line 51 in FIGS. 4 and 5 (b). When the pressure is low, the maximum discharge amount is adjusted by the maximum flow rate adjusting unit 6 in the vertical direction as indicated by the dotted line and the arrow 41. The maximum pressure is adjusted by the high pressure spring 11 by the pressure adjusting screw 13 as indicated by the dotted line and the arrow 42. Pressure adjustment on the low pressure side is not considered. These are the same as before. In the present embodiment, by adjusting the position of the sleeve 12 with the screw 12a, the discharge amount in the high pressure region can be adjusted to the vertical arrow 45 as shown by the dotted line in FIG. Furthermore, the pressure-axis input characteristic in such a case can adjust the axis input in the high pressure region to an up / down arrow 46 as shown by the dotted line in FIG.

  Thus, for example, even if the rotation speed differs depending on the difference between 50 Hz and 60 Hz, the maximum discharge amount and the discharge amount at high pressure can be adjusted, and the shaft input can be raised and lowered, respectively, so that the motor efficiency can be effectively applied. Can do. Further, the output size of the electric motor can be reduced. By reducing the output of the motor, the load factor of the motor in the pressure holding state of the pump is increased, so that the motor can be operated in a more efficient state and energy is saved. Further, as the motor output size is reduced, the power supply capacity of the apparatus can also be reduced. When the pressure in the low pressure region is adjusted, as shown by the dotted line of the arrow 43 in FIGS. 5 (a) and 5 (b), it only changes in the horizontal direction in the figure, and for different rotational speeds. It cannot be an efficient axis input characteristic.

  Next, a second embodiment of the present invention will be described with reference to FIG. In addition, about the thing similar to 1st embodiment mentioned above, the same code | symbol is attached | subjected or abbreviate | omitted and a part or all of description is abbreviate | omitted. The control device for the variable displacement vane pump of the second embodiment is one in which a sleeve is integrated. As shown in FIG. 2, the cylindrical intermediate portion 12i of the sleeve is joined by welding, an outer reduced diameter portion 12h is provided at the other end of the sleeve, and a screw hole 12d is directly provided. In this case, the piston 14, the high-pressure spring 11, and the holder 10 are assembled in this order in the cylindrical portion before welding.

  Next, a third embodiment of the present invention will be described with reference to FIG. In addition, about the thing similar to 1st embodiment mentioned above, the same code | symbol is attached | subjected or abbreviate | omitted and a part or all of description is abbreviate | omitted. In the control device for the variable displacement vane pump according to the third embodiment, welding of the intermediate portion of the cylindrical portion of the sleeve is stopped, and the reduced diameter portion 12c of the sleeve can be disassembled and assembled. As shown in FIG. 3, an outer diameter-reduced portion 12h is provided at the other end of the sleeve 12, and a screw hole 12d is provided directly. The through hole 12b side of the inner diameter 12f of the sleeve is opened as it is, and a snap ring 21 is fitted in a snap ring groove 20 provided at the opening end of the inner diameter 12f. A washer 12 'is sandwiched between the snap ring and the flange 10a of the holder 10 to form a reduced diameter portion 12c having a through hole 12b. As a result, it is possible to disassemble and assemble compared to the second embodiment while reducing the outer shape compared to the first embodiment.

DESCRIPTION OF SYMBOLS 1 Variable displacement type vane pump 2 Pump main body 5 Cam ring 6 Maximum flow rate adjusting part 8 Plunger 8e Plunger anti-cam ring side surface 9 Low pressure spring 9a Low pressure spring cam ring side 9b Low pressure spring anti cam ring side 10 Holder 10a Holder flange 10b Holder Bottom 10c of the cam ring side contact surface 10d of the holder cylinder outer diameter 10e outer diameter 11 high pressure spring 12 sleeve 12a male screw 12b on the outer periphery of the sleeve through hole 12c reduced diameter portion 12d of sleeve screw hole 12g 12h Outwardly reduced diameter portion 12i Cylindrical portion middle portion 13 Pressure adjusting portion (pressure adjusting screw)
e Eccentricity

Claims (4)

  Regulates the maximum eccentricity of the cam ring in a variable displacement vane pump pressure and flow control device that changes the eccentric amount of a square cam ring according to the load pressure and discharges the discharge amount required for operation. The maximum flow rate adjusting portion and the maximum flow rate adjusting portion are provided on the opposite side of the cam ring and have a low pressure spring for biasing the cam ring, and the low pressure spring is inserted into the cam ring side abutting surface. A holder, a high-pressure spring that urges the holder toward the cam ring side, a pressure adjustment unit that adjusts the high-pressure spring force, and the cam ring-side contact surface to move the holder in the cam ring direction. A sleeve for regulating the holder, and the holder has the cam ring side contact surface within the allowable eccentricity of the cam ring. It made possible selectively contact with any of the ring, the variable displacement vane pump controller and wherein the cam ring position of the sleeve is adjustable. The holder holds the anti-cam ring side of the low-pressure spring, the low-pressure spring is in contact with the cam ring via a plunger, and the sleeve has a cylindrical shape having a reduced diameter portion at the tip, and the pump body The low-pressure spring is in contact with the cam ring via the plunger through the through hole in the reduced diameter portion, and the cam ring-side contact surface of the holder is in contact with the cam ring. 2. The control apparatus for a variable displacement vane pump according to claim 1, wherein the control unit is configured to be selectively abutted against an anti-cam ring side surface of the reduced diameter portion or an anti-cam ring side surface of the plunger.
The holder has a cylindrical shape having a flange at one end and a bottom at the other end. The outer diameter of the cylindrical portion is smaller than the inner diameter of the high-pressure spring, and a part or all of the low-pressure spring is inserted. 3. The control device for a variable displacement vane pump according to claim 2, wherein the control unit is configured to be able to abut on a side surface of the reduced diameter portion opposite to the cam ring .
  The sleeve has a cylindrical shape with a male screw provided on the outer periphery, one end has the reduced diameter portion having the through hole, and the other end has an outer reduced diameter portion having a screw hole, 4. The control device for a variable displacement vane pump according to claim 3, wherein a middle portion of the cylindrical portion of the sleeve is joined by welding, and a pressure adjusting screw of the pressure adjusting portion is screwed into the screw hole.

Images