JP4527597B2 - Vane pump - Google Patents

Description

  The present invention relates to a vane pump used as a drive source for a power steering device of a vehicle, and more particularly to a variable displacement vane pump that controls a discharge flow rate by changing a capacity of a pump body.

  2. Description of the Related Art Conventionally, for example, as a drive source for a power steering device of a vehicle, a cam ring provided in a housing and a rotor disposed on the inner peripheral side thereof and driven to rotate are provided so as to be able to protrude and retract in the radial direction of the rotor. In addition, a vane pump that performs pump operation by changing the volume of a pump chamber formed in adjacent vanes of a plurality of vanes is used.

  The variable displacement vane pump controls the discharge flow rate of the pump by moving the cam ring eccentrically with respect to the rotor, thereby reducing the pump driving force and saving energy.

In such a vane pump, the profile of the cam ring is a perfect circle, or, for example, as described in Patent Document 1 below, in the suction section, the total flow rate of the vane back pressure chamber is always constant regardless of the progress of rotation. It was designed to be a profile.
JP 2004-23973 A

  In the vane pump as described above, the cam ring is deformed by the pressure applied to the inner and outer circumferences of the cam ring as the discharge pressure increases, and an appropriate cam profile cannot be maintained. For this reason, there is a problem that discharge characteristics change and abnormal noise is generated from the pump.

  In particular, in the variable displacement vane pump, since one suction region and one discharge region are provided, the span in which the pressure is applied in the same direction of the cam ring is large, and the pressure change on the outer peripheral side of the cam ring is large, so that the cam ring is deformed. Remarkably easy to appear.

  That is, during actual operation (as the discharge pressure increases), the cam ring is deformed by the pressure acting on the cam ring. Conventionally, however, the profile has been designed without considering the deformation of the cam ring. For this reason, there has been a problem that during actual operation, the cam design curve deviates greatly and pump pulsation, vibration and noise increase.

  The present invention has been made in view of the above points, and an object thereof is to provide a vane pump in which pump pulsation, vibration and noise are reduced.

The invention according to claim 1 for solving the above SL problem, a rotor which is driven to rotate is disposed in the housing, a vane which is provided retractably in the radially slots provided in the rotor , together with the swingably mounted within said housing a swing fulcrum disposed in the housing as a fulcrum, is formed in an annular shape, and the cam ring to form a plurality of pumping chambers with the rotor and the vanes on the inner peripheral side ,
A suction port that is provided on both sides of the cam ring in the axial direction and that opens to at least one side thereof in an area where the volume of the plurality of pump chambers increases; and a discharge port that opens in an area where the volume of the plurality of pump chambers decreases. And a sealing member provided on the outer peripheral side of the cam ring and separating the outer peripheral side space of the cam ring into a first fluid pressure chamber and a second fluid pressure chamber. In the vane pump that swings the cam ring by the hydraulic pressure guided to the pressure chamber and the second fluid pressure chamber, and changes the volume of the plurality of pump chambers,
The profile of the cam ring is a discharge region where the volumes of the plurality of pump chambers are reduced in a state where no hydraulic pressure is applied, and a profile closer to the first fluid pressure chamber than the swing fulcrum, and a discharge region The profile on the second fluid pressure chamber side of the swing fulcrum has a shape that bulges inward in the radial direction from the perfect circle, and swells more radially inward than the profile at the swing fulcrum. It is characterized by having a shape.

In the variable displacement vane pump configured as described above, since one suction region and one discharge region are provided, the span in the same direction of the cam ring is large and the pressure change on the outer peripheral side of the cam ring is also large. For this reason, when the pressure rises during actual operation, when the cam ring is deformed as if it is pushed from the high pressure side to the low pressure side due to the pressure difference between the inner and outer circumferences of the cam ring, It becomes a profile, and the effect of reducing pulsation, noise, and vibration can be further obtained.

  In the variable displacement vane pump configured as described above, since one suction region and one discharge region are provided, the span in the same direction of the cam ring is large and the pressure change on the outer peripheral side of the cam ring is also large. For this reason, when the pressure increases during actual operation, when the cam ring is deformed as if it was pushed from the high pressure side to the low pressure side due to the pressure difference between the inner and outer circumferences of the cam ring, It becomes a profile, and the effect of reducing pulsation, noise, and vibration can be further obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. 1 and 2 show an example of the basic configuration of a variable displacement vane pump. FIG. 1 shows a cross-sectional view of the main part of the pump cut perpendicular to the axis of the pump drive shaft. FIG. The cross section of the principal part cut | disconnected along the axis line is shown.

  In FIG. 2, reference numeral 20 denotes a pump housing of a variable displacement vane pump according to the present invention. The pump housing 20 is coupled to a housing main body 21 having a recess 21 a for accommodating the pump main body, and the housing main body 21. And a rear cover 22 that closes the recess 21a.

  A drive shaft 23 driven by the vehicle engine is rotatably supported on the pump housing 20, and a rotor 24 is coupled to the drive shaft 23 so as to be integrally rotatable. As shown in FIG. 1, the rotor 24 is formed with a plurality of vane slots 70 in the radial direction of the outer peripheral side, and the vanes 25 are accommodated in the slots 70 so as to be able to appear and retract.

  In FIG. 1, reference numeral 26 denotes a cam ring that constitutes a pump main body together with the rotor 24 and accommodates the rotor 24 on the inner peripheral side. The cam ring 26 has a substantially circular shape in which the tips of the vanes 25 are in sliding contact. An inner surface is provided. The profile of the cam ring 26 will be described in detail later.

  The cam ring 26 is supported by a pin 27 (first support point) so that a part of the outer periphery of the cam ring 26 (lower end in the figure) can swing freely in the pump housing 20. The amount of eccentricity with respect to 24 can be adjusted. In FIG. 1, O indicates the rotation center of the rotor 24 and the drive shaft 23, and O 'indicates the center of the cam ring 26. The center O' of the cam ring 26 is displaced in the left-right direction in FIG. To do.

  In this vane pump, since the cam ring 26 is normally eccentric with respect to the rotation center O, when the rotor 24 rotates while the tip of the vane 25 is in sliding contact with the inner peripheral surface of the cam ring 26, the adjacent vanes 25, 25 are arranged. The volume of the pump chamber formed in the cylinder is increased or decreased, thereby continuously operating the pump. When the eccentric amounts of the cam ring 26 and the rotor 24 change, the volume change rate of the pump chamber changes, and the pump capacity changes accordingly.

  Reference numeral 28 denotes a ring-shaped member that is fitted into the recess 21a of the pump housing 20 and forms a housing space for the cam ring 26 therein. Reference numeral 29 (see FIG. 2) denotes the ring-shaped member 28 and the recess 21a. It is the side plate accommodated in. The ring-shaped member 28 is formed of a hard material slightly wider than the three widths of the rotor 24, the vane 25, and the cam ring 26, and the inner peripheral surface thereof is substantially elliptical so as to allow the cam ring 26 to swing. It is formed in a shape. The ring-shaped member 28 is engaged with a pin 27 that is a swing center of the cam ring 26, and the pin 27 prevents rotation.

  A seal member 30 (FIG. 1) spring-biased radially inward is disposed at a position (position shifted by approximately 180 ° from the inner periphery) opposite to the position of the pin 27 on the inner peripheral surface of the ring-shaped member 28. The seal member 30 is in close contact with the outer peripheral surface of the cam ring 26 while allowing the cam ring 26 to be displaced (swinged).

  The seal member 30 divides the inner space of the ring-shaped member 28 together with the pin 27 into a first fluid pressure chamber 1 on the left side in FIG. 1 and a second fluid pressure chamber 2 on the right side in FIG. The pressure of the hydraulic oil introduced into the chambers 1 and 2 acts on the cam ring 26 from the opposite direction. When the cam ring 26 is displaced in the first fluid pressure chamber 1 direction to the maximum, the eccentric amount with respect to the rotor 24 is maximized. Conversely, when the cam ring 26 is displaced in the second fluid pressure chamber 2 direction to the maximum, the eccentric amount is minimized. become.

  The side plate 29 closes both sides of the ring-shaped member 28 together with the inner wall of the pump housing 20 (inner wall of the rear cover 22), and also slidably closes the side of the cam ring 26.

  On the other hand, a through hole 43 having a predetermined diameter is formed in a portion of the peripheral wall of the ring-shaped member 28 facing the second fluid pressure chamber 2, as shown in FIG. A bottomed cylindrical spring accommodating portion 44 is formed at a position continuous with the through hole 43, and an urging spring 45 is accommodated in the spring accommodating portion 44. The tip of the urging spring 45 protrudes into the second fluid pressure chamber 2 through the through-hole 43 and contacts the outer peripheral surface of the cam ring 26. The cam ring 26 is moved in the first fluid pressure chamber 1 direction (the amount of eccentricity is maximized). It is energizing in the direction.

  Incidentally, on the inner circumference of the ring-shaped member 28 on the first fluid pressure chamber 1 side, the suction area a (the upper half area in FIG. 1) and the discharge area b (the lower half area in FIG. 1). A raised portion 28a (second support point) that slightly protrudes toward the cam ring 26 is formed in the vicinity of the boundary.

  The raised portion 28a makes contact with the outer peripheral surface of the cam ring when the cam ring 26 is biased in the first fluid pressure chamber 1 direction (maximum eccentric direction), thereby reducing the space of the first fluid pressure chamber 1 as shown in the figure. Work to ensure.

  Further, as shown in FIG. 2, a recess that forms a low pressure chamber 33 and a high pressure chamber 34 is formed between the bottom surface of the recess 21 a of the pump housing 20 and the side plate 29. 34 is electrically connected to the suction area a and the discharge area b in the cam ring 26 through communication holes 35 and 36 formed in the side plate 29. The suction area a in the cam ring 26 is connected to the suction port 37, and the discharge area b is connected to the discharge port 38. The side plate 29 receives the pressure of the hydraulic fluid in the high pressure chamber 34 and presses the ring-shaped member 28 toward the rear cover 22.

  The pump housing 20 above the ring-shaped member 28 (on the seal member 30 side) is provided with a control valve 57 that controls the discharge flow rate of the hydraulic oil. The control valve 57 is formed with an upstream fluid chamber 61, an intermediate fluid chamber 62, and a downstream fluid chamber 63 that are separated by a valve body 58 having partition pieces 58a and 58b. A spring 64 biases the valve body 58 toward the upstream fluid chamber 61 side.

  The intermediate fluid chamber 62 is supplied with hydraulic oil from the tank 80. The hydraulic oil in the tank 80 is also supplied to the suction area a through the suction passage 81. Discharge hydraulic fluid is introduced into the upstream fluid chamber 61 via a discharge passage 82 communicating with the discharge region b (discharge port 38). An orifice 84 is inserted in a discharge passage 83 communicating with the discharge region (discharge port 38). The hydraulic oil on the downstream side of the orifice 84 is supplied to a hydraulic actuator (not shown) and to the downstream fluid chamber 63 of the control valve 57.

  Reference numeral 85 denotes a communication passage (return port) having one end opened near the boundary between the upstream fluid chamber 61 and the intermediate fluid chamber 62. Reference numeral 86 denotes a communication path having one end opened near the boundary between the intermediate fluid chamber 62 and the downstream fluid chamber 63. The hydraulic oil in the control valve 57 is introduced into the first fluid pressure chamber 1 through the hole 87 provided in the communication passage 85 and the ring-shaped member 28, and the communication passage 86 and the hole 88 provided in the member 28 are provided. It is configured so as to be introduced into the second fluid pressure chamber 2.

  1 and 2, the opening area of the orifice 84 is adjusted according to the displacement of the cam ring 26 in the axial direction of the urging spring 45, but the mechanism is not shown. .

  Next, the operation of the vane pump configured as described above will be described with reference to FIGS. FIG. 3 is a schematic view of the main configuration of FIGS. 1 and 2, and the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals. FIG. 4 is a characteristic diagram showing the relationship between the pump speed and the discharge flow rate.

  First, when starting the pump operation, as shown in FIG. 3A, the valve body 58 of the control valve 57 is urged toward the upstream fluid chamber 61 by the spring 64, and the cam ring 26 is urged by the urging spring 45. It is urged toward the raised portion 28a (maximum eccentric state). Accordingly, since the partition piece 58a of the valve body 58 is located on the upstream fluid chamber 61 side, the communication passage 85 communicates with the intermediate fluid chamber 62, and the first fluid pressure chamber 1 communicates with the intermediate fluid chamber 62 and the communication fluid from the tank 80. Tank pressure is introduced through the passage 85 and the hole 87.

  Further, since the partition piece 58b of the valve body 58 is located on the intermediate fluid chamber 62 side, the communication passage 86 communicates with the downstream fluid chamber 63, and the second fluid pressure chamber 2 has the downstream fluid chamber 63, the communication passage 86 and the hole. The downstream pressure of the orifice 84 is introduced via 88.

  In the maximum eccentric state of the cam ring 26 shown in FIG. 3A, the opening area of the orifice 84 is adjusted to the maximum opening area by an adjusting mechanism (not shown).

  When the drive shaft 23 is rotated by starting the engine, the rotor 24 rotates in the cam ring 26 in a state where the cam ring 26 is displaced to the maximum eccentric position. Thus, when the rotor 24 rotates, the pump operation is continuously performed in the cam ring 26, and the hydraulic oil sucked into the suction area a from the tank 80 and pressurized by the vane 25 is discharged from the discharge area b to the discharge passages 82 and 83. Is discharged. The hydraulic oil discharged to the discharge passage 82 is introduced into the upstream fluid chamber 61 of the control valve 57, and the hydraulic oil discharged to the discharge passage 83 passes through the orifice 84 and is supplied to a hydraulic actuator (not shown). On the other hand, it is introduced into the downstream fluid chamber 63 of the control valve 57.

  At this time, a differential pressure is generated before and after the orifice 84, and the differential pressure acts on the valve body 58 of the control valve 57. The valve body 58 is upstream of the fluid chamber by the spring 64 until the differential pressure reaches a set value. It is pressed to the 61 side. Therefore, the first fluid pressure chamber 1 and the second fluid pressure chamber 2 are maintained at substantially the same pressure, and the discharge flow rate is as in section A in FIG. 4 until the differential pressure across the orifice 84 becomes equal to or higher than the set pressure. It increases in proportion to the increase in the rotational speed of the rotor 24.

  When the rotational speed of the rotor 24 increases and the differential pressure across the orifice 84 becomes equal to or higher than the set pressure (that is, the pressure in the first fluid pressure chamber 1> the pressure in the second fluid pressure chamber 2), the valve body 58 of the control valve 57 is Due to the differential pressure, the fluid is displaced toward the downstream fluid chamber 63 as shown in FIG.

  Accordingly, the partition piece 58a of the valve body 58 is located on the intermediate fluid chamber 62 side, so that the communication passage 85 communicates with the upstream fluid chamber 61, and the first fluid pressure chamber 1 includes the discharge passage 82, the upstream fluid chamber. 61, the orifice upstream pressure is introduced through the communication passage 85 and the hole 87.

  Further, since the partition piece 58 b of the valve body 58 is located on the downstream fluid chamber 63 side, the communication path 86 communicates with the intermediate fluid chamber 62, and the tank pressure is applied to the second fluid pressure chamber 2 via the intermediate fluid chamber 62. be introduced.

  Then, the cam ring 26 is displaced toward the second fluid pressure chamber 2 as shown in FIG. 3B by the pressure of the first fluid pressure chamber 1, and the amount of eccentricity with respect to the rotor 24 decreases. Then, the opening area of the orifice 84 is reduced by an adjustment mechanism (not shown) according to the displacement, and as a result, the vane pump reduces the discharge flow rate contrary to the rotational speed of the rotor 24 as shown in section B of FIG. A so-called flow-down characteristic is exhibited, and an increase in the temperature of hydraulic oil and an increase in driving torque are prevented.

  The vane pump shown in FIGS. 1, 2 and 3 is a so-called total pressure type (high pressure type) as a cam ring drive system. However, the present invention is not limited to this and can be applied to a differential pressure type and low pressure type vane pump. It is.

  FIG. 5 is a schematic diagram of the three drive systems of the cam ring, and the same parts as those in FIGS. The differential pressure type in FIG. 5A differs from the total pressure type in FIG. 5B in that a communication passage 91 connecting the downstream fluid chamber 63 and the hole 88 is provided instead of the communication passage 86. In addition, the low pressure type in FIG. 5C is different from the total pressure type in FIG. 5B in that the communication path 92 connecting the tank 80 and the second fluid pressure chamber 2 is used instead of the communication path 86 and the hole 88. Is in the point provided.

  In any driving method, the upstream pressure of the orifice 84 and the tank pressure are selectively introduced into the first fluid pressure chamber 1.

  In the second fluid pressure chamber 2, the downstream pressure of the orifice is always introduced in the differential pressure type of (a), and the downstream pressure of the orifice and the tank pressure are selectively introduced as described above in the total pressure type of (b). The low pressure type is configured so that the tank pressure is always introduced.

  Next, the profile of the cam ring of the present invention will be described. In the present invention, the cam ring is grasped by the cam ring deformed due to the pressure acting on the cam ring, and the cam shape is corrected in advance.

  6 and 7 show how the cam ring is deformed during the operation of the actual vane pump for the differential pressure type, the total pressure type, and the low pressure type cam ring, and the deformation shape and the deformation are corrected. It is a figure showing a design profile.

  6 and 7, the same parts as those in FIGS. 1 to 3 are denoted by the same reference numerals. Low, medium, and high in the drawings indicate pressures, and solid circles indicate shapes when the cam ring is a perfect circle. In the figure, the alternate long and short dash line shows the actual cam ring deformation shape during operation, and the broken line shows the profile of the cam ring of the present invention.

  6 shows a low rotation time (section A in FIG. 4), FIG. 7 shows a high rotation speed (section B in FIG. 4), and the broken lines in (a), (c), and (e) are simply pressures. The broken lines in (b), (d), and (f) indicate the shapes when the influence of surroundings other than the pressure is taken into consideration.

  First, at the time of differential pressure type low rotation, as shown in FIG. 5 (a), the cam ring 26 is in the maximum eccentric state, and a tank pressure is introduced into the first fluid pressure chamber 1, so that a low pressure is applied to the second fluid. Since the downstream pressure of the orifice 84 is introduced into the pressure chamber 2, an intermediate pressure is applied.

  For this reason, the cam ring in the suction region a and the region on the second fluid pressure chamber 2 side is deformed inward by the internal / external differential pressure biased from the outside to the inside, and is the discharge region b and the region on the second fluid pressure chamber 2 side. The cam ring is deformed to the outside by the internal / external differential pressure biased from the inside to the outside, and the cam ring in the discharge region b and the region on the first fluid pressure chamber 1 side is outside by the internal / external differential pressure biased from the inside to the outside. (Indicated by the alternate long and short dash line in the figure).

  Therefore, in this embodiment, as indicated by the broken line in the figure, the deformation due to the pressure is taken into consideration and the cam ring profile is provided with the deformation on the opposite side in advance.

  That is, the profile of the cam ring in the suction region a and the region on the second fluid pressure chamber 2 side is a shape 2a that protrudes outward from the perfect circle indicated by the solid line, and the discharge region b and the second fluid pressure chamber 2 side. The profile of the cam ring in the region is a shape 2b that protrudes inward from the perfect circle shown by the solid line, and the profile of the cam ring in the region on the discharge region b and the first fluid pressure chamber 1 side is from the perfect circle shown by the solid line The shape 1b is convex inward.

  As a result, when the cam ring is deformed due to the differential pressure inside and outside the cam ring during actual operation, an appropriate cam ring profile is obtained, and the suction and discharge characteristics of the pump are improved.

  Here, when considering various conditions other than the pressure in designing the profile of the cam ring, the ridge that contacts the vicinity of the pin 27 (first support point), which is the rocking fulcrum of the cam ring, and at the time of maximum eccentricity. Since the cam ring is hardly deformed near the portion 28a (second support point), there is no problem even if the profile of the cam ring near the first and second support points is substantially circular.

  In addition, even if the cam ring receives loads in different directions in adjacent areas, it does not cause a sudden reverse deformation at the boundary, and gradually changes from concave to convex or convex to concave shape. Similarly, the offset shape smoothly changes the unevenness.

Therefore, at the time of differential pressure type low rotation, as shown in FIG. 6 (b), the profile of the suction region a and the region on the first fluid pressure chamber 1 side is set to the inner side of the solid circle as in the shape 1b. The shape is a convex shape 1a ′ (provided that the profile of the region near the second fluid pressure chamber 2 of 1a ′ has a shape 1a ₂ ′ that protrudes outward from the perfect circle).

Further, in FIG. 6A, since the shape change of the unevenness is severe at the boundary between the shape 2a and the shape 2b, as shown in FIG. 6B, the discharge region b and the second fluid pressure chamber 2 side, The profile of the region close to the first fluid pressure chamber 1 is a shape 2b ₁ ′ that protrudes inward from the perfect circle, and the profile of the region near the suction region a on the second fluid pressure chamber 2 side in the discharge region b. The shape 2ba ′ is convex outward from the perfect circle.

  Next, at the time of low rotation of the total pressure type, as shown in FIG. 5B, the cam ring 26 is in the maximum eccentric state, and since the tank pressure is introduced into the first fluid pressure chamber 1, a low pressure is applied. Since the downstream pressure of the orifice 84 is introduced into the fluid pressure chamber 2, an intermediate pressure is applied.

  Thus, since the pressure applied to each part is the same as that at the time of the differential pressure type low rotation, the deformed shape (dashed line) at the time of actual operation is the same as FIG. 6A as shown in FIG. 6C. Therefore, the profile of the cam ring according to the present invention (broken line shape) is also designed to be the same as that of FIGS. 6A and 6B, as shown in FIGS. Also, the operations and effects in FIGS. 6C and 6D are the same as those in FIGS.

  Next, at the time of the low pressure type low rotation of FIG. 6E, the cam ring 26 is in the maximum eccentric state as shown in FIG. 5C, and the tank pressure is introduced into the first fluid pressure chamber 1. A low pressure is applied, and a low pressure is applied to the second fluid pressure chamber 2 because the tank pressure is introduced.

  For this reason, the cam ring in the discharge region b and the region on the first fluid pressure chamber 1 side is deformed to the outside by the internal / external differential pressure biased from the inside to the outside, and the discharge region b and the region on the second fluid pressure chamber 2 side The cam ring is deformed to the outside by an internal / external differential pressure biased from the inside to the outside (one-dot chain lines in the drawing).

  Therefore, in this embodiment, as indicated by the broken line in the figure, the deformation due to the pressure is taken into consideration and the cam ring profile is provided with the deformation on the opposite side in advance.

  That is, the profile of the cam ring in the discharge region b and the region on the first fluid pressure chamber 1 side is a shape 1b that protrudes inward from the perfect circle indicated by the solid line, and the discharge region b and the second fluid pressure chamber 2 side The profile of the cam ring in this area is a shape 2b that protrudes inward from the perfect circle indicated by the solid line.

  As a result, when the cam ring is deformed by the differential pressure inside and outside the cam ring during actual operation, an appropriate cam ring profile is obtained, and the discharge characteristics of the pump are improved.

Further, in consideration of the influence of the surroundings, as shown in FIG. 6 (f), the profile of the region near the second fluid pressure chamber 2 on the first fluid pressure chamber 1 side, as shown in FIG. The profile 1a ₂ ″ is convex outward, and the profile of the suction region a and the region near the discharge region b on the first fluid pressure chamber 1 side is the shape 1 ab ″ convex inward from the perfect circle. In addition, the profile of the region near the first fluid pressure chamber 1 on the second fluid pressure chamber 2 side in the suction region a is a shape 2a ₁ ″ that protrudes outward from the perfect circle, and the suction region a and the second fluid pressure chamber 2 side. The profile of the region near the discharge region b on the fluid pressure chamber 2 side is assumed to be a shape 2ab ″ that protrudes inward from the perfect circle.

  Next, at the time of differential pressure type high rotation in FIG. 7A, the differential pressure across the orifice 84 in FIG. 5A increases and the valve body 58 of the control valve 57 is displaced, so that the partition piece 58a becomes an intermediate fluid. Located on the chamber 62 side, an orifice upstream pressure is introduced into the first fluid pressure chamber 1 and a high pressure is applied. In addition, the downstream pressure of the orifice 84 is introduced into the second fluid pressure chamber 2 and an intermediate pressure is applied. Therefore, the cam ring in the suction region a and the region on the first fluid pressure chamber 1 side is deformed inward by the internal / external differential pressure biased from the outside to the inside, and the suction region a and the region on the second fluid pressure chamber 2 side The cam ring is deformed inward by an internal / external differential pressure biased from the outside to the inside, and the cam ring in the discharge region b and the region on the first fluid pressure chamber 1 side is deformed by the internal / external differential pressure biased from the inside to the outside. (Indicated by the alternate long and short dash line in the figure).

  Therefore, in this embodiment, as indicated by the broken line in the figure, the deformation due to the pressure is taken into consideration and the cam ring profile is provided with the deformation on the opposite side in advance.

  That is, the profile of the cam ring in the suction region a and the region on the first fluid pressure chamber 1 side is a shape 1a that protrudes outward from the perfect circle indicated by the solid line, and in the suction region a and on the second fluid pressure chamber 2 side. The profile of the cam ring in the region is a shape 2a that protrudes outward from the perfect circle indicated by the solid line, and the profile of the cam ring in the region on the discharge region b and the second fluid pressure chamber 2 side is from the true circle indicated by the solid line The shape 2b is convex inward.

  As a result, when the cam ring is deformed due to the differential pressure inside and outside the cam ring during actual operation, an appropriate cam ring profile is obtained, and the suction and discharge characteristics of the pump are improved.

Further, in FIG. 7A, irregularities are formed at the boundary between the perfect circle shape of the discharge region b and the region on the first fluid pressure chamber 1 side and the shape 1a of the suction region a and the region on the first fluid pressure chamber 1 side. Since the shape change is severe, as shown in FIG. 7B, the profile of the region near the suction region a on the first fluid pressure chamber 1 side in the discharge region b is a shape that protrudes outward from the perfect circle. The profile of the region near the second fluid pressure chamber 2 on the first fluid pressure chamber 1 side in the discharge region b is defined as a shape 1b ₂ that protrudes inward from the perfect circle.

  Next, in the total pressure type of FIG. 7C, since the differential pressure across the orifice 84 of FIG. 5B increases and the valve body 58 of the control valve 57 is displaced, the partition piece 58a is moved to the intermediate fluid chamber 62 side. In the first fluid pressure chamber 1, the orifice upstream pressure is introduced and a high pressure is applied. Further, since the partition piece 58b is located on the downstream fluid chamber 63 side, a tank pressure is introduced into the second fluid pressure chamber 2 and a low pressure is applied.

  For this reason, the cam ring in the suction region a and the region on the first fluid pressure chamber 1 side is deformed inward by the internal / external differential pressure biased from the outside to the inside, and is the discharge region b and the region on the second fluid pressure chamber 2 side. The cam ring is deformed to the outside by an internal / external differential pressure biased from the inside to the outside (one-dot chain lines in the drawing).

  Therefore, in this embodiment, as indicated by the broken line in the figure, the deformation due to the pressure is taken into consideration and the cam ring profile is provided with the deformation on the opposite side.

  That is, the profile of the cam ring in the suction area a and the area on the first fluid pressure chamber 1 side is a shape 1a that protrudes outward from the perfect circle indicated by the solid line, and is in the discharge area b and on the first fluid pressure chamber 1 side. The profile of the cam ring in the region is a shape 1b that protrudes inward from the perfect circle indicated by the solid line, and the profile of the cam ring in the region on the discharge region b and the second fluid pressure chamber 2 side is from the true circle indicated by the solid line The shape 2b is convex inward.

  As a result, when the cam ring is deformed due to the differential pressure inside and outside the cam ring during actual operation, an appropriate cam ring profile is obtained, and the suction and discharge characteristics of the pump are improved.

In FIG. 7C, the shape of the unevenness changes at the boundary between the shapes 1a and 1b and at the boundary between the shape 2b and the region of the suction area a and the perfect circular shape on the second fluid pressure chamber 2 side. Since it is intense, as shown in FIG. 7 (d), the profile of the region near the second fluid pressure chamber 2 on the first fluid pressure chamber 1 side in the suction region a is convex outward from the perfect circle. 1a ₂ ″, the profile of the suction region a and the region near the discharge region b on the first fluid pressure chamber 1 side is a shape 1ab ″ that protrudes inward from the perfect circle, and the suction region a and the second The profile of the region near the first fluid pressure chamber 1 on the fluid pressure chamber 2 side is a shape 2a ₁ ″ protruding outward from the perfect circle, and the discharge in the suction region a and on the second fluid pressure chamber 2 side The profile of the region near the region b is a shape 2ab ″ that is convex inward from the perfect circle.

  Next, at the time of the low pressure type high rotation of FIG. 7 (e), the differential pressure across the orifice 84 of FIG. 5 (c) increases and the valve body 58 of the control valve 57 is displaced. Located on the fluid chamber 62 side, an orifice upstream pressure is introduced into the first fluid pressure chamber 1 to apply an intermediate pressure. The tank pressure is introduced into the second fluid pressure chamber 2 so that a low pressure is applied. Since the pressure applied to each part is the same as that at the time of the high pressure of the total pressure type, the deformed shape (the one-dot chain line) at the time of actual operation is the same as FIG. 7 (c) as shown in FIG. 7 (e). Therefore, the profile of the cam ring according to the present invention (broken line shape) is also designed to be the same as that of FIGS. 7C and 7D, as shown in FIGS. Also, since the operations and effects in FIGS. 7E and 7F are the same as those in FIGS. 7C and 7D described above, description thereof will be omitted.

  FIG. 8 shows the relationship between the pump rotation speed and the pump pulsation level when the cam ring having the profile of the present invention is applied. 8 (a) shows a low load, FIG. 8 (b) shows a medium load, and FIG. 8 (c) shows a high load. In either case, the characteristics of the conventional pump indicated by the solid line are shown. It can be seen that the characteristics of the pump according to the present invention indicated by broken lines are better.

  In addition, the present invention is not limited to the variable displacement vane pump, and when applied to a vane pump that employs a fixed cam ring, similarly to the above, it has a profile that is given in advance a deformation opposite to the deformation during actual operation. As a result, the same actions and effects as described above can be obtained.

Further, technical ideas other than the claims that can be grasped from the above embodiment will be described together with the effects thereof.
(A) The vane pump according to claim 2 is provided in an orifice provided in a discharge passage communicating with the discharge port, a switching valve for guiding a differential pressure across the orifice, and the second fluid pressure chamber. Urging means for urging the cam ring from the second fluid pressure chamber side to the first fluid pressure chamber side, and the switching valve transmits a pressure guided to the first fluid pressure chamber to the orifice. The upstream side pressure and the atmospheric pressure are switched, the downstream side pressure of the orifice is guided to the second fluid pressure chamber, and the profile of the cam ring in the suction region and the second fluid pressure chamber region And the profile in the suction region and in the region of the first fluid pressure chamber are each configured in a shape that bulges outwardly from the circular shape.

  With this configuration, in the maximum eccentric state of the cam ring, the first fluid pressure chamber side has a low pressure and the second fluid pressure chamber side has a high pressure. Further, since the cam ring is urged toward the first fluid pressure chamber by the urging means, the stability of the cam ring is good.

  Further, when the cam ring is deformed by the internal / external differential pressure of the cam ring urging from the cam ring outer side (second fluid pressure chamber side) to the inner side (suction region side) in the suction region and the second fluid pressure chamber region, It becomes a profile of a cam ring, and the suction characteristics of the pump can be improved.

Further, at the time of high pump rotation, the pressure on the first fluid pressure chamber side becomes higher than the pressure on the second fluid pressure chamber side and the suction region. For this reason, the cam ring is deformed by the differential pressure inside and outside the cam ring that urges from the cam ring outer side (first fluid pressure chamber side) to the inner side (suction region side) in the suction region and the first fluid pressure chamber region at the time of high pump rotation. As a result, an appropriate cam ring profile is obtained, and the suction characteristics of the pump can be improved.
(B) In the vane pump according to the item (a), the profile in the discharge region of the cam ring and the region of the first fluid pressure chamber and the profile in the fluid pressure of the discharge region and the second fluid pressure chamber are circular. Further, each is formed in a shape that bulges toward the inner peripheral side.

  In this configuration, when the pump is rotating at a low speed, the pressure on the first fluid pressure chamber side becomes lower than the pressure in the discharge region. For this reason, the cam ring is deformed by the differential pressure inside and outside the cam ring that urges from the cam ring inner side (discharge region side) to the outer side (first fluid pressure chamber side) in the discharge region and in the first fluid pressure chamber region during low pump rotation. As a result, an appropriate cam ring profile is obtained, and the discharge characteristics of the pump can be improved.

Further, the pressure in the discharge region is higher than the pressure in the second fluid pressure chamber at both low and high rotations. For this reason, when the cam ring is deformed by the differential pressure inside and outside the cam ring that is biased from the cam ring inner side (discharge region side) to the outer side (second fluid pressure chamber side) in the discharge region and the second fluid pressure chamber region, It becomes a profile of a cam ring, and the discharge characteristic of the pump can be improved.
(C) The vane pump according to claim 2 is provided in an orifice provided in a discharge passage communicating with the discharge port, a switching valve for guiding a differential pressure across the orifice, and the second fluid pressure chamber. Urging means for urging the cam ring from the second fluid pressure chamber side to the first fluid pressure chamber side, and the switching valve transmits a pressure guided to the first fluid pressure chamber to the orifice. The upstream pressure and the atmospheric pressure are switched, and the pressure guided to the second fluid pressure chamber is configured to switch between the downstream pressure of the orifice and the atmospheric pressure, and in the suction region and the second of the cam ring. The profile in the region of the fluid pressure chamber and the profile in the region of the suction region and the first fluid pressure chamber are each configured to have a shape that bulges outward from the circle.

  With this configuration, in the maximum eccentric state of the cam ring, the first fluid pressure chamber side has a low pressure and the second fluid pressure chamber side has a high pressure. Further, since the cam ring is urged toward the first fluid pressure chamber by the urging means, the stability of the cam ring is good.

  Further, when the cam ring moves in a direction in which the eccentric amount decreases, atmospheric pressure is gradually introduced into the second fluid pressure chamber, so that the cam ring has good responsiveness.

  When the pump is rotating at a low speed, the pressure on the second fluid pressure chamber side becomes higher than the pressure in the suction region. For this reason, the cam ring is deformed by the differential pressure inside and outside the cam ring that urges from the cam ring outer side (second fluid pressure chamber side) to the inner side (suction region side) in the suction region and the second fluid pressure chamber region at the time of low pump rotation. As a result, an appropriate cam ring profile is obtained, and the discharge characteristics of the pump can be improved.

When the pump is rotating at a high speed, the pressure on the first fluid pressure chamber side becomes higher than the pressure in the suction region. For this reason, the cam ring is deformed by the differential pressure inside and outside the cam ring that urges from the cam ring outer side (first fluid pressure chamber side) to the inner side (suction region side) in the suction region and the first fluid pressure chamber region at the time of high pump rotation. As a result, an appropriate cam ring profile is obtained, and the suction characteristics of the pump can be improved.
(D) In the vane pump according to (C), the cam ring has a profile in the discharge region and the first fluid pressure chamber, and a profile in the discharge region and the fluid pressure in the second fluid pressure chamber. Each is configured to swell in a convex shape toward the inner peripheral side rather than a circle.

  In this configuration, the pressure in the discharge region is higher than the pressure on the first fluid pressure chamber side during low pump rotation. For this reason, the cam ring is deformed by the differential pressure inside and outside the cam ring that urges from the cam ring inner side (discharge region side) to the outer side (first fluid pressure chamber side) in the discharge region and in the first fluid pressure chamber region during low pump rotation. As a result, an appropriate cam ring profile is obtained, and the discharge characteristics of the pump can be improved.

Further, when the pump is rotating at high speed, the pressure in the discharge region becomes higher than the pressure on the second fluid pressure chamber side. For this reason, the cam ring is deformed by the differential pressure inside and outside the cam ring that urges from the cam ring inner side (discharge region side) to the outer side (second fluid pressure chamber side) in the discharge region and the second fluid pressure chamber region at the time of high pump rotation. As a result, an appropriate cam ring profile is obtained, and the discharge characteristics of the pump can be improved.
(E) The vane pump according to claim 2 is provided in an orifice provided in a discharge passage communicating with the discharge port, a switching valve for guiding a differential pressure across the orifice, and the second fluid pressure chamber. Urging means for urging the cam ring from the second fluid pressure chamber side to the first fluid pressure chamber side, and the switching valve transmits a pressure guided to the first fluid pressure chamber to the orifice The upstream side pressure and the atmospheric pressure are switched, the atmospheric pressure is guided to the second fluid pressure chamber, the profile of the cam ring in the discharge region and the region of the second fluid pressure chamber, and the discharge Each of the profiles in the region and the region of the first fluid pressure chamber is formed in a shape that bulges in a convex shape toward the inner peripheral side of the circle.

  According to this configuration, in the maximum eccentric state of the cam ring, since the entire circumference of the cam ring is at atmospheric pressure, no pressure leakage occurs between the first fluid pressure chamber and the second fluid pressure chamber, so that the pump efficiency is good.

  Further, the pressure in the discharge region is higher than the pressure in the second fluid pressure chamber at both low and high rotations. For this reason, when the cam ring is deformed by the differential pressure inside and outside the cam ring that is biased from the cam ring inner side (discharge region side) to the outer side (second fluid pressure chamber side) in the discharge region and the second fluid pressure chamber region, It becomes a profile of a cam ring, and the discharge characteristic of the pump can be improved.

Further, the pressure in the discharge region becomes higher than the pressure in the first fluid pressure chamber, particularly when the pump is rotating at a low speed. For this reason, when the cam ring is deformed by the cam ring inner / outer differential pressure biased from the cam ring inner side (discharge region side) to the outer side (first fluid pressure chamber side) in the discharge region and the first fluid pressure chamber region, It becomes a profile of a cam ring, and the discharge characteristic of the pump can be improved.
(F) In the vane pump according to the item (e), the profile of the cam ring in the suction region and the first fluid pressure chamber region is configured to bulge outwardly from a circle.

In this configuration, the pressure of the first fluid pressure chamber becomes higher than the pressure of the suction region during high pump rotation. For this reason, the cam ring is deformed by the differential pressure inside and outside the cam ring that urges from the cam ring outer side (first fluid pressure chamber side) to the inner side (suction region side) in the suction region and the first fluid pressure chamber region at the time of high pump rotation. As a result, an appropriate cam ring profile is obtained, and the suction characteristics of the pump can be improved.
(G) The vane pump according to claim 2 is a first support point that supports the swinging of the cam ring at a boundary point between the first fluid pressure chamber and the second fluid pressure chamber in the discharge region, A second support point on the first fluid pressure chamber side and supporting a cam ring in the vicinity of the boundary between the suction region and the discharge region, and the profile of the cam ring is set near the first support point and the second support point. A substantially circular shape is formed in the vicinity of the point.

  In this configuration, the cam ring profile hardly changes even if the pressure changes near the first support point and the second support point. Therefore, by adopting a circular shape, appropriate suction and discharge characteristics can be obtained. .

The principal part sectional drawing cut | disconnected orthogonally to the axis line of the pump drive shaft of the vane pump of one embodiment of this invention. The principal part sectional drawing cut | disconnected along the axis line of the pump drive shaft of the vane pump of one embodiment of this invention. The outline of the full pressure type vane pump of one embodiment of the present invention is expressed, (a) is a mimetic diagram at the time of low rotation, and (b) is a mimetic diagram at the time of high rotation. The characteristic view which shows the relationship between the pump speed and discharge flow volume in a variable displacement vane pump. The various cam ring drive systems of the vane pump to which this invention is applied are represented, (a) is a schematic diagram of a differential pressure type, (b) is a schematic diagram of a total pressure type, (c) is a schematic diagram of a low pressure type. The embodiment of the profile of the cam ring at the time of low rotation of the vane pump of the present invention is shown, (a), (c), (e) are profile explanatory views when only pressure is considered, (b), (d), (F) is a profile explanatory view when the influence of the surroundings is taken into consideration. The embodiment of the profile of the cam ring at the time of high rotation of the vane pump of the present invention is shown, (a), (c), (e) are profile explanatory views when only pressure is considered, (b), (d), (F) is a profile explanatory view when the influence of the surroundings is taken into consideration. The characteristic view which shows the relationship between a pump rotation speed and a pulsation level at the time of each load of low, middle, and high of the pump using the cam ring of this invention, and the conventional pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st fluid pressure chamber, 2 ... 2nd fluid pressure chamber, 20 ... Pump housing (housing), 21 ... Housing main body, 22 ... Rear cover (clamping member), 23 ... Drive shaft, 24 ... Rotor, 25 ... Vane, 26 ... Cam ring, 27 ... Pin (first support point), 28 ... Ring-shaped member, 28a ... Raised portion (second support point), 29 ... Side plate (clamping member), 30 ... Seal member, 33 ... Low pressure chamber, 34 ... High pressure chamber, 37 ... Suction port, 38 ... Discharge port, 45 ... Biasing spring, 57 ... Control valve, 58 ... Valve body, 61 ... Upstream fluid chamber, 62 ... Intermediate fluid chamber, 63 ... Downstream fluid chamber 64, spring, 80, tank, 81, suction passage, 82, 83, discharge passage, 84, orifice, 85, 86, communication passage, 87, 88, hole, a, suction region, b, discharge region.

Claims (1)

A rotor disposed in the housing and driven to rotate;
A vane provided in a slot provided in the rotor so as to be able to appear and disappear in a radial direction;
A cam ring with swingably mounted within said housing a swing fulcrum disposed in the housing as a fulcrum, is formed in an annular shape to form a plurality of pumping chambers with the rotor and the vanes on the inner peripheral side,
A suction port provided on both sides in the axial direction of the cam ring and opening on at least one side thereof in a region where the volumes of the plurality of pump chambers increase; and a discharge port opening in a region where the volumes of the plurality of pump chambers decrease. A clamping member comprising:
A seal member provided on the outer peripheral side of the cam ring, and separating the outer peripheral side space of the cam ring into a first fluid pressure chamber and a second fluid pressure chamber;
In the vane pump that swings the cam ring by the hydraulic pressure guided to the first fluid pressure chamber and the second fluid pressure chamber, and changes the volume of the plurality of pump chambers,
The profile of the cam ring is a discharge region in which the volumes of the plurality of pump chambers are reduced in a state where no hydraulic pressure is applied, a profile on the first fluid pressure chamber side with respect to the swing fulcrum, and a discharge region. The profile on the second fluid pressure chamber side of the swing fulcrum has a shape that bulges inward in the radial direction from the perfect circle, and swells more radially inward than the profile at the swing fulcrum. A vane pump characterized by having a shape .

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