JP2010196682A - Vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vane pump with a flow control valve simply constructed to be well controllable. <P>SOLUTION: The vane pump 100 includes the flow control valve 102 for controlling the flow of operating fluid to be supplied from a high pressure chamber 14 to hydraulic equipment. The flow control valve 102 has a spool 20 which is moved depending on front-rear differential pressure in a throttle to return the operating fluid discharged from the high pressure chamber 14 to the suction side of the pump. It also has a first high pressure passage 21 communicated directly with the high pressure chamber 14 for introducing operating oil discharged from the high pressure chamber 14 into a pressure chamber 23 defined on the front end side of the spool 20, and a second high pressure passage 22 mounted with the throttle and communicated directly with the high pressure chamber 14 for introducing the operating oil discharged from the high pressure chamber 14 into a back pressure chamber 24 defined on the back face side of the spool 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vane pump, and more particularly, to a vane pump including a flow control valve that controls a flow rate of a working fluid supplied from a vane pump to a hydraulic device.

  As a conventional vane pump, one having a flow control valve for controlling the flow rate of hydraulic oil supplied to a hydraulic device is known.

  Patent Document 1 discloses a flow control valve that returns hydraulic oil discharged from a high-pressure chamber to the pump suction side in accordance with the differential pressure across the variable throttle.

JP-A-9-170569

  In the flow control valve described in Patent Document 1, the hydraulic oil downstream of the variable throttle that is guided to the back pressure chamber of the spool is guided through a passage branched from the main passage that guides the hydraulic fluid from the high pressure chamber to the hydraulic equipment.

  In this way, when the passage for guiding the hydraulic oil to the back pressure chamber of the spool is branched and formed, the length of the branch passage becomes long, so the pressure loss of the hydraulic oil increases, and the differential pressure across the variable throttle Does not act correctly on both ends of the spool. In this case, the controllability of the flow control valve may be adversely affected.

  Further, when the branch passage is processed, since an opening that opens to the outside is formed in the body, a member for sealing the opening is required, and the structure becomes complicated.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a vane pump having a flow rate control valve with good controllability and a simple structure.

  The present invention is a vane pump including a flow control valve that controls a flow rate of a working fluid supplied from a high pressure chamber to a hydraulic device, and the flow control valve moves according to a differential pressure before and after a throttle, and the high pressure chamber And a spool that returns the working fluid discharged from the pump to the pump suction side, communicates directly with the high-pressure chamber, and guides hydraulic oil discharged from the high-pressure chamber to a pressure chamber defined on the tip side of the spool. A high-pressure passage and a second high-pressure passage that is directly connected to the high-pressure chamber and guides hydraulic oil discharged from the high-pressure chamber to a back pressure chamber defined on the back side of the spool. And.

  According to the present invention, since the second high pressure passage for guiding the hydraulic oil downstream of the throttle to the back pressure chamber on the back side of the spool is formed in direct communication with the high pressure chamber, the length of the second high pressure passage is shortened. Can do. Therefore, the pressure loss of the working fluid in the second high-pressure passage can be reduced, and the controllability of the flow rate control valve is improved. Further, when processing the second high-pressure passage, it can be processed so that the high-pressure chamber and the back pressure chamber are in direct communication, and the second high-pressure passage can have a simple structure.

It is sectional drawing of the vane pump which concerns on embodiment of this invention. It is a top view of the pump cartridge in the vane pump concerning an embodiment of the invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  With reference to FIG.1 and FIG.2, the vane pump 100 which concerns on embodiment of this invention is demonstrated.

  The vane pump 100 is used as a hydraulic pressure supply source for hydraulic equipment mounted on a vehicle, for example, a power steering device or a continuously variable transmission.

  As shown in FIG. 1, the vane pump 100 includes a pump cartridge 101 that discharges hydraulic oil (working fluid), and a flow rate that controls the flow rate of hydraulic oil discharged from the pump cartridge 101 and supplied to hydraulic equipment (not shown). And a control valve 102.

  As shown in FIG. 2, the pump cartridge 101 is such that the power of an engine (not shown) as a power source is transmitted to the end of the drive shaft 1 and the rotor 2 connected to the drive shaft 1 rotates. .

  The pump cartridge 101 contains a plurality of vanes 3 provided so as to be capable of reciprocating in the radial direction with respect to the rotor 2, and accommodates the rotor 2, and the tip end portion of the vane 3 on the inner cam surface 4 a as the rotor 2 rotates. And a cam ring 4 that slides.

  In the rotor 2, slits 16 having openings on the outer peripheral surface are radially formed at predetermined intervals, and the vanes 3 are slidably inserted into the slits 16.

  A back pressure chamber 17 into which pump discharge pressure is guided is defined on the proximal end side of the slit 16. Adjacent back pressure chambers 17 communicate with each other by an arc-shaped groove 2a formed in the rotor 2, and pump discharge pressure is always guided to the groove 2a. The vane 3 is pressed in the direction of popping out of the slit 16 by the pressure of the back pressure chamber 17, and the tip part abuts on the cam surface 4 a on the inner periphery of the cam ring 4. Thus, a plurality of pump chambers 7 are defined inside the cam ring 4 by the outer peripheral surface of the rotor 2, the cam surface 4 a of the cam ring, and the adjacent vanes 3.

  The cam ring 4 is an annular member having an inner peripheral cam surface 4 a having an elliptical shape, and includes a suction region that expands the volume of the pump chamber 7 and a discharge region that contracts the volume of the pump chamber 7. In the present embodiment, the cam ring 4 has two suction areas and two discharge areas.

  A pump cover (not shown) is disposed in contact with one side of the rotor 2 and the cam ring 4, and a side plate 6 is disposed in contact with the other side. In this way, the pump cover and the side plate 6 are arranged with both side surfaces of the rotor 2 and the cam ring 4 being sandwiched, and seal the pump chamber 7.

  On the surface of the pump cover where the rotor 2 slides, two arc-shaped suction ports that open to correspond to the suction region of the cam ring 4 and guide the hydraulic oil to the pump chamber 7 are formed in a groove shape.

  The side plate 6 is formed with two arc-shaped discharge ports 9 that open corresponding to the discharge region of the cam ring 4 and guide the hydraulic oil discharged from the pump chamber 7 to the high-pressure chamber 14.

  Each pump chamber 7 sucks the hydraulic oil through the suction port in the suction region of the cam ring 4 as the rotor 2 rotates, and discharges the hydraulic oil through the discharge port 9 in the discharge region of the cam ring 4. Thus, each pump chamber 7 supplies and discharges hydraulic oil by expansion and contraction accompanying the rotation of the rotor 2.

  The drive shaft 1 is rotatably supported by the pump body 10. As shown in FIG. 1, the pump body 10 is formed with a pump housing recess 10a in which the side plate 6 and the pump cartridge 101 are stacked and housed. In FIG. 1, the upper side of the boundary line X is a plan view and the lower side is a cross-sectional view, and the plan view shows a state in which nothing is accommodated in the pump accommodating recess 10 a.

  An annular groove 15 is formed at the bottom of the pump housing recess 10a, and the high pressure chamber 14 is defined by closing the annular groove 15 with a side plate 6 disposed at the bottom of the pump housing recess 10a. The hydraulic oil discharged from the pump chamber 7 is guided to the high pressure chamber 14 through a discharge port 9 formed through the side plate 6.

  The pump housing recess 10 a is sealed by fastening a pump cover to the end surface 10 b of the pump body 10.

  Next, the flow control valve 102 will be described with reference to FIG.

  The flow control valve 102 is accommodated in an assembly hole 10 c formed in the pump body 10.

  The spool 20 is slidably inserted into the assembly hole 10c, and the cap 30 is screwed into the opening of the assembly hole 10c.

  A pressure chamber 23 into which hydraulic oil discharged from the high pressure chamber 14 through the first high pressure passage 21 is directly guided is defined at the front end side of the spool 20. Further, on the back side of the spool 20, a back pressure chamber 24 to which hydraulic oil discharged from the high pressure chamber 14 through the second high pressure passage 22 is directly guided is defined. A spring 28 that urges the spool 20 in a direction to expand the volume of the back pressure chamber 24 is accommodated in the back pressure chamber 24.

  The assembly hole 10c has a discharge port 26 for communicating a supply passage (not shown) for supplying hydraulic oil to the hydraulic equipment and the pressure chamber 23, and a return passage (not shown) for returning the hydraulic oil to the pump suction side. And a return port 27 communicating with each other. A rod portion 20a formed at the tip of the spool 20 is inserted into the discharge port 26, and a restriction is formed by the discharge port 26 and the rod portion 20a.

  The second high-pressure passage 22 is provided with a throttle (not shown) that provides resistance to the flow of hydraulic oil. Therefore, the hydraulic oil downstream of the throttle is guided to the back pressure chamber 24, and the pressure in the high pressure chamber 14 is reduced and guided. On the other hand, since the throttle is not interposed in the first high pressure passage 21, the pressure of the high pressure chamber 14 is guided to the pressure chamber 23 without being reduced. In this way, the differential pressure across the throttle acts on each end of the spool 20 through the first high-pressure passage 21 and the second high-pressure passage 22 configured as separate passages. The spool 20 moves according to the differential pressure across the throttle, and balances at a position where the load based on the differential pressure across the throttle and the biasing force of the spring 28 are balanced.

  The operation of the flow control valve 102 will be described. When the pump rotational speed is low and the flow rate of the hydraulic oil discharged from the pump chamber 7 is small, the pressure loss at the throttle of the second high-pressure passage 22 is small. And the pressure difference between the back pressure chamber 24 is small. Therefore, the spool 20 is urged by the urging force of the spring 28, and the return port 27 is closed by the land portion 20b of the spool 20 (the state shown in FIG. 1). As a result, the hydraulic oil guided from the high pressure chamber 14 to the pressure chamber 23 through the first high pressure passage 21 is guided from the discharge port 26 to the supply passage and supplied to the hydraulic equipment. For this reason, hydraulic oil proportional to the number of revolutions of the pump is supplied to the hydraulic equipment.

  From the state shown in FIG. 1, if the pump rotational speed increases and the flow rate of hydraulic oil discharged from the pump chamber 7 increases, the pressure loss at the throttle of the second high-pressure passage 22 increases. The pressure difference with the pressure chamber 24 increases. Therefore, the spool 20 moves while compressing the spring 28, and the return port 27 communicates with the pressure chamber 23. As a result, part of the hydraulic oil guided from the high pressure chamber 14 to the pressure chamber 23 through the first high pressure passage 21 is returned to the return passage through the return port 27.

  As the flow rate of hydraulic oil discharged from the pump chamber 7 increases, the pressure loss at the throttle of the second high-pressure passage 22 increases, so that the amount of movement of the spool 20 increases and the opening area of the return port 27 increases. Therefore, the flow rate of the hydraulic oil that returns to the return passage increases as the flow rate of the hydraulic oil discharged from the pump chamber 7 increases. For this reason, after the return port 27 communicates with the pressure chamber 23, the flow rate of the hydraulic oil supplied to the hydraulic equipment through the discharge port 26 is kept substantially constant.

  Next, the first high pressure passage 21 and the second high pressure passage 22 will be described.

  As described above, the first high-pressure passage 21 and the second high-pressure passage 22 are respectively formed in direct communication with the high-pressure chamber 14, and the hydraulic oil in the high-pressure chamber 14 is separately supplied to the pressure chamber 23 and the back pressure chamber 24. It is a guide.

  The second high pressure passage 22 is formed independently of the first high pressure passage 21 and directly communicates with the high pressure chamber 14, so that the high pressure chamber 14 and the back pressure chamber 24 are directly connected through the second high pressure passage 22. Therefore, since the length of the second high-pressure passage 22 can be shortened, the pressure loss of the hydraulic oil in the second high-pressure passage 22 is reduced. For this reason, the pressure of the hydraulic fluid guided from the high pressure chamber 14 to the back pressure chamber 24 is affected only by the pressure reduction by the throttle interposed in the second high pressure passage 22. Thus, the differential pressure before and after the throttle acts accurately on both ends of the spool 20, and the controllability of the flow control valve 102 is improved.

  The second high-pressure passage 22 may be formed so as to connect the high-pressure chamber 14 and the back pressure chamber 24 in a straight line. However, as shown in FIG. 1, it is desirable to provide at least one bent portion 31 in the middle. .

  This is because when the hydraulic oil passes through the throttle of the second high-pressure passage 22, the air dissolved in the hydraulic oil is generated as a bubble due to a jet flow, but the second high-pressure passage 22 is linearly formed. This is because, if formed, the generated bubbles are directly guided to the back pressure chamber 24 and erosion may occur in the spool 20 and the cap 30.

  By providing the bent portion 31 in the second high-pressure passage 22, bubbles generated when the hydraulic oil passes through the throttle abuts on the bent portion 31 before reaching the back pressure chamber 24. There is no direct guidance. Therefore, the occurrence of erosion to the spool 20 and the cap 30 can be prevented.

  Here, in the continuously variable transmission, since the oil in the gear case is agitated by the internal equipment, a large amount of air is dissolved in the hydraulic oil. Therefore, when the vane pump 100 is used as a hydraulic pressure supply source of the continuously variable transmission, bubbles are easily generated when the hydraulic oil passes through the throttle of the second high-pressure passage 22, and erosion is likely to occur. Therefore, the bent portion 31 is particularly effective when the vane pump 100 is used as a hydraulic pressure supply source for a continuously variable transmission.

  Specifically, the second high-pressure passage 22 includes a first passage 32 that communicates with the high-pressure chamber 14 and a second passage 33 that communicates with the back-pressure chamber 24, and the bent portion 31 includes the first passage 32 and the first passage 32. It is formed by connecting the two passages 33 with a predetermined angle.

  The first passage 32 on the upstream side is formed with a larger diameter than the second passage 33 on the downstream side. By setting the diameter of the passage in this way, the flow of hydraulic oil can be stabilized. Further, by forming the second passage 33 on the downstream side, which is the spool 20 side, with a small diameter, the hydraulic oil flowing into the assembly hole 10c is accurately guided to a position where the erosion is hardly generated structurally in the assembly hole 10c. be able to. Therefore, generation | occurrence | production of the erosion to the spool 20, the cap 30, and the assembly hole 10c can be prevented more.

  The second high-pressure passage 22 may be configured by connecting three or more passages. In that case, the diameter of the upstream passage is formed larger than the diameter of the downstream passage.

  Since the second high-pressure passage 22 is formed independently of the first high-pressure passage 21 and directly communicates with the high-pressure chamber 14, when the second high-pressure passage 22 is processed, the high-pressure chamber 14 and the back pressure chamber 24 Can be processed to communicate directly with each other. Specifically, a drill is inserted into the high-pressure chamber 14 to process the first passage 32 toward the assembly hole 10c, and a drill is inserted into the assembly hole 10c to form the second passage 33 toward the high-pressure chamber 14. The first passage 32 and the second passage 33 are connected by processing. By processing the second high-pressure passage 22 in this way, the pump body 10 is not formed with an opening that opens to the outside, so that a member for sealing the opening is not necessary. In this way, the second high-pressure passage 22 can have a simple structure.

  Moreover, as shown in FIG. 1, the second passage 33 is preferably formed so as to open at the side of the first passage 32. As a result, a bag portion 34 in which hydraulic oil is accumulated is formed at the downstream end of the first passage 32. In this way, by forming the bag portion 34 in the middle of the second high-pressure passage 22, bubbles generated when the hydraulic oil passes through the throttle of the second high-pressure passage 22 are easily collected in the bag portion 34. The occurrence of erosion on the cap 20 and the cap 30 can be further prevented.

  According to the above embodiment, the following operational effects are obtained.

  Since the second high pressure passage 22 that guides hydraulic oil downstream of the throttle to the back pressure chamber 24 on the back side of the spool 20 is formed in direct communication with the high pressure chamber 14, the length of the second high pressure passage 22 can be shortened. it can. Therefore, the pressure loss of the hydraulic oil in the second high-pressure passage 22 can be reduced, and the controllability of the flow control valve 102 is improved. Further, when the second high pressure passage 22 is processed, the high pressure chamber 14 and the back pressure chamber 23 can be processed to directly communicate with each other, and the second high pressure passage 22 can have a simple structure.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The vane pump according to the present invention can be applied to a hydraulic power supply source such as a power steering device or a transmission for a vehicle.

1 Drive shaft 2 Rotor 4 Cam ring 7 Pump chamber 10c Assembly hole 14 High-pressure chamber 20 Spool 21 First high-pressure passage 22 Second high-pressure passage 23 Pressure chamber 24 Back pressure chamber 26 Discharge port 27 Return port 31 Bend portion 100 Vane pump 101 Pump cartridge 102 Flow control valve

Claims (4)

A vane pump including a flow rate control valve for controlling a flow rate of a working fluid supplied from a high pressure chamber to a hydraulic device,
The flow rate control valve includes a spool that moves according to the differential pressure across the throttle and returns the working fluid discharged from the high pressure chamber to the pump suction side,
A first high-pressure passage that communicates directly with the high-pressure chamber and guides the hydraulic oil discharged from the high-pressure chamber to a pressure chamber defined on the front end side of the spool;
A second high-pressure passage that is directly connected to the high-pressure chamber and that guides hydraulic oil discharged from the high-pressure chamber to a back pressure chamber defined on the back side of the spool;
A vane pump comprising:   The vane pump according to claim 1, wherein the second high-pressure passage has at least one bent portion.   The second high-pressure passage is formed by connecting a plurality of passages with a predetermined angle, and the upstream passage has a larger diameter than the downstream passage. Vane pump.   The vane pump according to any one of claims 1 to 3, wherein the vane pump is used as a hydraulic pressure supply source of a continuously variable transmission.

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