JP5335940B2 - Variable displacement pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement pump reducing power loss by setting pump discharge pressure close to necessary hydraulic pressure. <P>SOLUTION: This pump is provided with a pump structure body discharging lubricating oil introduced to a plurality of pump chambers 13 from a suction port 7 by being driven and rotated by a crankshaft to an inside of an engine and a variable valve device from a discharge port 8 with receiving volume change of the pump chamber. Volume of the pump chamber is changed by oscillating a cam ring 5 by discharging pressure supplied in a control fluid chamber 16. Inside and outside two first and second coil springs 20, 21 urging the cam ring so as to increase the volume of the pump chamber are provided in parallel. Both springs are set in such a manner that the spring constant thereof increases as oscillation quantity of the cam ring in the direction reducing volume change quantity of the pump chamber increases. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a variable displacement pump that supplies lubricating oil to, for example, sliding parts of an internal combustion engine for automobiles, a variable valve mechanism that controls the operating characteristics of an engine valve, and the like.

  As this type of conventional variable displacement pump, a vane type pump described in Patent Document 1 below is known.

  In brief, suction ports and discharge ports are provided on both sides of the pump housing, and a drive shaft through which a rotational force is transmitted from the crankshaft of the internal combustion engine is disposed through substantially the center. Inside the pump housing, a rotor coupled to the drive shaft and holding a plurality of vanes on the outer peripheral side so as to be able to advance and retreat in a substantially radial direction, and an inner peripheral surface provided on the outer peripheral side of the rotor so as to be able to swing eccentrically. In addition, a cam ring in which the tip of each vane is in sliding contact is accommodated.

  The cam ring swings in the direction in which the amount of eccentricity decreases around the pivot pin in accordance with the pump discharge pressure introduced into the control oil chamber separated by a seal member on the outer periphery, and is integrated with the outer periphery. It swings in a direction in which the amount of eccentricity is increased by the spring force of a single coil spring that presses the lever portion.

  That is, in the initial state, the cam ring is biased in the direction in which the amount of eccentricity is maximized by the spring force of the coil spring to increase the discharge pressure, and when the hydraulic pressure in the control oil chamber exceeds a predetermined value, the cam ring is moved to the coil. The discharge pressure is decreased by swinging in a direction in which the amount of eccentricity is reduced against the spring force of the spring. As a result, an excessive increase in the discharge pressure from the suction port to the discharge port via each hydraulic oil chamber is suppressed to prevent power loss.

Japanese Patent Laid-Open No. 05-79469 (FIG. 1 etc.)

  However, in the conventional variable displacement pump, although the pump discharge pressure can be increased or decreased depending on the eccentric amount of the cam ring, the actual control discharge pressure becomes larger than the required discharge pressure. Loss cannot be reduced sufficiently.

The present invention has been devised in view of the actual situation of each of the conventional variable displacement pumps, and is a variable motion that controls the operating characteristics of an engine valve by lubrication or oil pressure to each sliding portion of an internal combustion engine for automobiles. A variable displacement pump that supplies oil as an operating source of a valve mechanism, and is rotated by the internal combustion engine, and a rotor having a plurality of slots formed outward, and can be freely advanced and retracted into the respective slots. By accommodating a plurality of slidingly held vanes and the rotor on the inner periphery, a plurality of hydraulic oil chambers are formed by the rotor and the plurality of vanes, and the amount of eccentricity with respect to the rotor is increased by swinging. A cam ring to be changed, a restricting portion for restricting the maximum eccentric amount of the cam ring, and constantly biasing the cam ring in a direction in which the eccentric amount of the cam ring with respect to the rotor is maximized. When the swinging amount of the first spring member and the cam ring is less than a predetermined value, the cam ring is not biased by being held in a state where a set load is applied, and when the swinging amount of the cam ring exceeds a predetermined value, A second spring member that biases the cam ring in a direction in which the amount of eccentricity of the cam ring increases, a control oil chamber that moves in a direction in which the amount of eccentricity of the cam ring decreases according to the introduced hydraulic pressure,
With
When the rotor rotates, oil sucked into the hydraulic oil chamber is discharged to each sliding portion of the automobile internal combustion engine and the variable valve mechanism.

  According to the present invention, the actual control discharge pressure can be brought close to the required discharge pressure by the urging means having a unique configuration, so that the power loss can be sufficiently reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a first embodiment of a variable displacement pump according to the present invention, partially cut away. It is a disassembled perspective view of a present Example. It is a front view which shows the pump housing provided to a present Example. It is operation | movement explanatory drawing of a present Example. It is operation | movement explanatory drawing of a present Example. FIG. 5 is a characteristic diagram showing a relationship between discharge hydraulic pressure and engine speed. It is a characteristic view which shows the relationship between the discharge hydraulic pressure and engine speed in a present Example. It is a characteristic view which shows the relationship between the spring displacement of a 1st, 2nd coil spring and a spring set load in a present Example. It is a front view which shows a 2nd example partially in section. It is an operation explanatory view of the 2nd example similarly. It is an operation explanatory view of the 2nd example similarly. It is a characteristic view which shows the relationship between the spring displacement of a 1st, 2nd coil spring and a spring set load in a present Example. It is a front view which shows a 3rd example partially in section. A is an exploded front view showing the first and second plungers used in this embodiment, and B is a cross-sectional view thereof. It is operation | movement explanatory drawing of the Example. It is operation | movement explanatory drawing of the Example. It is a front view which shows a 4th example partially in section. It is operation | movement explanatory drawing of the Example. It is operation | movement explanatory drawing of the Example. It is a characteristic view which shows the relationship between the discharge hydraulic pressure and engine speed in a present Example. It is a characteristic view which shows the relationship between the spring displacement of a 1st, 2nd coil spring and a spring set load in a present Example. It is a front view showing a fifth example with a partial cross section. It is a front view showing a sixth example with a partial cross section. It is a front view showing a seventh example with a partial cross section. It is procedure explanatory drawing which forms each curved surface part of the accommodation recessed part in a present Example. It is procedure explanatory drawing which similarly forms each curved-surface site | part. It is a front view of the adjustment ring provided for a present Example. It is action | operation explanatory drawing of the pump discharge hydraulic pressure which acts on the said adjustment ring. It is operation | movement explanatory drawing of the Example. It is operation | movement explanatory drawing of the Example. It is a longitudinal cross-sectional view which shows 8th Example. It is operation | movement explanatory drawing of the Example. It is operation | movement explanatory drawing of the Example.

Hereinafter, embodiments of a variable displacement pump according to the present invention will be described in detail with reference to the drawings. In this embodiment, the lubricating oil of an internal combustion engine for automobiles is applied to an oil pump that supplies a valve timing control device, which is a variable valve operating device that controls the opening / closing timing of an engine sliding portion and an engine valve, respectively. Is shown.
[First embodiment]
The variable displacement pump in the first embodiment is applied to a vane type, and is provided at the front end portion of a cylinder block of an internal combustion engine. As shown in FIG. 1 and FIG. A closed cylindrical pump housing 1 that is closed, a drive shaft 3 that is driven to rotate by the crankshaft of the engine through almost the center of the pump housing 1, and is rotatably accommodated in the pump housing 1. A rotor 4 having a substantially E-shaped cross section coupled to the drive shaft 3 at the center, a cam ring 5 which is a movable member swingably disposed on the outer peripheral side of the rotor 4, A pair of small diameter vane rings 6 and 6 slidably disposed on both side surfaces on the peripheral side is provided.

  The pump housing 1 is integrally formed of an aluminum alloy material, and as shown in FIG. 3, the concave bottom surface 1a slides on one side of the cam ring 5, so that accuracy such as flatness and surface roughness can be obtained. Highly machined and the sliding range is formed by machining. At a predetermined position on the inner peripheral surface of the pump housing 1, a substantially circular groove-shaped receiving seat 1b serving as a pivot point of the cam ring 5 is formed, and substantially opposed to the receiving seat 1b across the center of the housing. A seal slidable contact surface 1c is formed at a position on which a seal member 14 (to be described later) of the cam ring 5 is slidably contacted. The seal sliding contact surface 1c has an arcuate surface formed by a radius centered on the receiving seat 1b.

  Since the receiving seat 1b and the seal sliding contact surface 1c are formed in a small R-shaped curved surface, only the portion is processed with a relatively small tool to shorten the processing time. Further, when processing the receiving seat 1b and the seal sliding contact surface 1c, a substantially heart-shaped minute recess 1d and an elongated minute recess 1e are formed as processing marks on the bottom surface 1a side, and the minute recesses 1d, 1e The presence does not hinder the swinging of the cam ring 5.

  The bottom surface 1a of the pump housing 1 is formed with a substantially crescent shaped suction port 7 on the left side on the seal sliding contact portion 1c side, and a substantially crescent shaped discharge port on the right half on the receiving seat 1b side. 8 are formed substantially opposite to each other.

  As shown in FIG. 3, the suction port 7 communicates with a suction port 7a for sucking lubricating oil in an oil pan (not shown), while the discharge port 8 passes through the oil main gallery from the discharge port 8a. Are connected to each sliding portion and the variable valve operating device. Further, on the outer peripheral side of the bearing hole 1f of the drive shaft 3 formed in the center of the bottom surface 1a, three oil reservoirs 9 for temporarily storing the lubricating oil discharged from the discharge port 8 are equally spaced in the circumferential direction. From here, the lubricating oil is supplied to the bearing hole 1 f through the bearing oil supply groove 10, and the lubricating oil is supplied to both side surfaces of the rotor 4 and side surfaces of the vane 11 to be described later. It comes to secure.

  In this embodiment, the cover 2 has a flat inner surface, but it is also possible to form a suction port, a discharge port, and an oil reservoir in the same manner as the bottom surface 1a. The cover 2 is attached to the housing body by a plurality of bolts B.

  The drive shaft 3 is configured such that the rotor 4 is rotated clockwise in FIG. 1 by the rotational force transmitted from the crankshaft. The left half in the drawing is the suction stroke, and the right half is the discharge process. .

  As shown in FIGS. 1 and 2, the rotor 4 has vanes 11 slidably held in a plurality of slots 4a formed radially outward from the inner center side. A back pressure chamber 12 having a substantially circular cross section for introducing the discharge hydraulic pressure discharged to the discharge port 8 is formed at the inner base end of 4a.

  Each vane 11 has a base end that is in sliding contact with the outer peripheral surface of the vane ring 6, and each distal end is slidably in contact with the inner peripheral surface of the cam ring 5. Further, a plurality of pump chambers 13 which are hydraulic fluid chambers are liquid-tight between the vanes 11 and the inner peripheral surface of the cam ring 5, the inner peripheral surface of the rotor 4, the bottom surface 1a of the pump housing 1, and the inner end surface of the cover 2. Are separated. Each vane ring 6 pushes each vane 11 radially outward.

  The cam ring 5 is integrally formed in a substantially cylindrical shape by a sintered metal that is easy to process, and is a substantially arc-shaped pivot portion that fits into the receiving groove 1b and serves as an eccentric swing fulcrum at a predetermined position on the outer peripheral surface 5a is integrally provided along the axial direction, and a seal member 14 that is slidably in contact with the seal slidable contact surface 1c at the time of eccentric swing is provided at a position substantially opposite to the pivot portion 5a.

  The seal member 14 is formed in an elongated shape along the axial direction of the cam ring 5 by, for example, a low wear synthetic resin material, and is fixed in a holding groove 5b in which the outer peripheral surface of the cam ring 5 is cut out in an arc shape. The rubber elastic member 15 is pressed forward by the elastic force of the rubber elastic member 15, that is, against the seal sliding contact surface 1c. Thereby, the good fluid-tightness of the control oil chamber 16 mentioned later is always ensured.

  A substantially crescent-shaped control oil chamber 16 is defined between the outer peripheral surface of the cam ring 5 and the inner peripheral surface of the pivot portion 5 a and the seal member 14 and the pump housing 1, and the front end of the cam ring 5. On the surface, an introduction passage 16a for introducing the discharge hydraulic pressure discharged from the discharge port 8 into the control oil chamber 16 is formed. The control oil chamber 16 moves in a concentric direction by reducing the amount of eccentricity with respect to the rotor 4 by swinging the cam ring 5 counterclockwise with the pivot portion 5a as a fulcrum by the discharge hydraulic pressure introduced from the introduction passage 16a. It is supposed to let you. The introduction passage 16a can be formed not in the front end face of the cam ring 5 but through the peripheral wall.

  The cam ring 5 is integrally provided with an arm 17 projecting radially outward at a position on the outer surface opposite to the pivot portion 5a. The arm 17 has a lower surface 17a on the distal end side formed in an arcuate curved surface shape.

  The pump housing 1, the drive shaft 3 and the rotor 4, the cam ring 5, the suction port 7, the discharge port 8, the vane 11, and the like constitute a pump structure.

  On the other hand, an urging means for constantly urging the cam ring 5 in the direction of the maximum eccentric amount via the arm 17 is provided at a portion opposite to the pivot portion 5 a of the pump housing 1.

  This urging means is arranged in parallel with a cylinder body 18 having a cylindrical shape made of an aluminum alloy and provided integrally with the pump housing 1, a plug 19 for closing the lower end opening of the cylinder body 18, and the cylinder body 18. Between the inner first coil spring 20 and the outer second coil spring 21, which are inner and outer double compression spring members housed and disposed between the tip of the first coil spring 20 and the lower surface 17 a of the arm 17. A first plunger 22 that is a pressing member disposed on the front end of the second coil spring 21 and a contact member that is slidably guided on the inner peripheral surface 18 a of the cylinder body 18. 2 plungers 23 mainly.

  The cylinder body 18 is gradually formed in a three-stage reduced diameter structure as the inner peripheral surface 18a goes upward from the lower end opening side, and the plug 19 is formed on the inner peripheral surface of the large lower end opening. A female screw 24a to which a male screw formed on the outer periphery is screwed is formed, and an annular shape in which the outer peripheral edge of the second plunger 23 abuts on a boundary portion between the middle diameter portion and the small diameter portion located on the upper portion thereof. A stopper protrusion 24b is formed. Further, the cylinder body 18 has the upper surface of the arm 17 in contact with the lower surface 18c of the upper end wall 18b when the arm 17 is rotated clockwise in the figure by the spring force of the first and second coil springs 21 and 21. Thus, the maximum eccentric position of the cam ring 5 is regulated.

  The plug 19 includes a substantially disk-shaped lid portion 19a on the bottom side, and a cylindrical portion 19b that stands integrally with the upper surface of the lid portion 19a and faces the inside of the cylinder body 18 from the lower end opening. The male screw 19c is formed on the outer periphery of the portion 19b so that the screwing amount of the male screw 19c and the female screw 24a can be adjusted, and the upper surface of the outer peripheral portion of the lid portion 19a is the upper surface of the cylinder body 18. The screwing is restricted to the maximum at the position in contact with the hole edge of the lower end opening.

  The first coil spring 20 has a coil diameter smaller than that of the second coil spring 21 and is disposed on the inner side, and its axial length is longer than that of the second coil spring 21. The lower end portion 20a is elastically contacted with the upper surface of the lid portion 19a, and the upper end portion 20b is elastically contacted with the lower surface of the plunger 22, so that a predetermined spring set load W1 is set. This spring set load W1 is a load at which the cam ring 5 starts to move when the hydraulic pressure is the required hydraulic pressure P1 of the variable valve operating apparatus.

  The first plunger 22 is formed in a solid columnar shape, and its flat upper surface is always in contact with the lower surface 17a of the arm 17, and a small-diameter columnar projection 22b is formed at the center of the lower surface. It is provided integrally. The protrusion 22b has an upper end 20b which is one end of the first coil spring 20 fitted and held, and the axial length L of the projection 22b is the upper portion of the second plunger 23 which will be described later. The wall 23a is extended to a position penetrating the spring insertion hole 23c, thereby preventing the first coil spring 20 from being collapsed or twisted during compression / extension deformation, thereby ensuring smooth deformation at all times. Yes. The first plunger 22 can be formed in a hollow shape in order to reduce the weight.

  The second coil spring 21 has a lower end portion 21a elastically contacting the upper surface of the lid portion 19a, and an upper end portion 21b elastically contacting the outer peripheral portion of the lower surface of the upper wall of the second plunger 23. The load is set to W2. The inner diameter of the second coil spring 21 is set to such a size that the outer peripheral surface does not hit the inner peripheral surface and can be freely compressed and expanded even when the first coil spring 20 is compressed and deformed. Yes. The predetermined set load W2 is a load at which the cam ring 5 starts to move when the hydraulic pressure is the required hydraulic pressure P2 during the maximum rotation of the crankshaft.

  Further, the winding directions of the first coil spring 20 and the second coil spring 21 are opposite to each other. Therefore, when the both 20 and 21 are compressed / expanded and deformed as described above, they do not mesh with each other, and a smooth deformation can be obtained at all times.

  The second plunger 23 is formed of a ferrous metal material in a cylindrical shape with a closed cylindrical cross section, and has a circular upper wall 23a and a cylindrical portion that hangs down from an outer peripheral lower end edge of the upper wall 23a. 23b, and a spring insertion hole 23c through which the second coil spring 21 is inserted is formed in the center of the upper wall 23a. The spring insertion hole 23c has a diameter that does not hit the outer peripheral surface of the first coil spring 20 even when the first coil spring 20 is compressed and is smaller than the outer diameter of the first plunger 22. Has been. Therefore, when the first plunger 22 is pushed down by the arm 17 of the cam ring 5 and lowered to a predetermined position, the outer peripheral portion of the lower surface 22a of the first plunger 22 comes into contact with the outer peripheral portion of the upper wall 23a.

  Further, the second plunger 23 moves up and down while being slidably guided in the inside diameter portion of the cylinder body inner peripheral surface 18a, and the maximum outer edge of the second plunger 23 comes into contact with the stopper projection 24b. The upward movement position is regulated.

  An adjustment member such as a spacer having a different thickness is appropriately interposed between the lid portion 19a of the plug 19 and the lower end opening edge of the cylinder body 18 to adjust the screwing amount. 1. The spring force of the second coil springs 21 and 21 can be freely changed.

  Then, the volume change of each pump chamber 13 is changed according to the amount of eccentricity of the cam ring 5 that changes depending on the relative pressure between each spring force of the first and second coil springs 21 and 21 and the discharge hydraulic pressure in the control oil chamber 16. As a result, the discharge hydraulic pressure discharged from the suction port 7 through the pump chambers 13 to the discharge port 8 changes.

  The cam ring 5, the vane rings 6 and 6, the control oil chamber 16, the biasing means, and the like constitute a variable mechanism.

  Hereinafter, the operation of the present embodiment will be described. Prior to this, the relationship between the hydraulic pressure controlled by the conventional variable displacement pump and the hydraulic pressure required for the engine sliding portion and the valve timing control device will be described with reference to FIG.

  The hydraulic pressure required for the internal combustion engine is mainly determined by the hydraulic pressure required for lubricating the bearing portion of the crankshaft, and this tends to increase with the engine speed, as indicated by the broken line C in FIG. In order to satisfy the required hydraulic pressure in all the engine rotation ranges, the hydraulic pressure at which the cam ring starts moving is set to the required hydraulic pressure P2 at the maximum rotation. As a result, the relationship between the engine speed and the control hydraulic pressure rises from the low speed range as shown by the solid line a in FIG. 6, and the hydraulic pressure tends to increase as the speed increases.

  In addition, when the variable valve device is used as a measure for improving fuel efficiency or exhaust emission, the oil pressure of the oil pump is used as an operating source of the device, so that the operating responsiveness of the device is improved. The high hydraulic pressure P1 shown by the broken line in FIG. Therefore, the hydraulic pressure required for the entire internal combustion engine is sufficient with the characteristics of the whole broken line connecting the broken lines b and c.

  However, in the conventional variable displacement pump, the cam ring is only urged in the direction of the maximum eccentric amount by a single coil spring having a constant spring set load. As described above, the oil pressure becomes high in line with the increase in the engine speed indicated by the solid line a in FIG. 6, that is, the oil pressure becomes higher than necessary in the hatched portion in FIG. 6, and the power loss is sufficiently suppressed. Can not.

  On the other hand, in this embodiment, as shown in FIG. 7, first, the pump discharge pressure does not reach P1 from the start of the internal combustion engine to the low rotation range, so the arm 17 of the cam ring 5 is the first. The coil spring 20 is pressed against the lower surface 18c of the cylinder body upper end wall 18b by the spring force, and is in an operation stop state (see FIG. 1). At this time, the eccentric amount of the cam ring 5 is the largest, the pump capacity is maximized, and the discharge hydraulic pressure rises more rapidly than the conventional one as the engine speed increases, and the characteristic shown in (a) on the solid line in FIG. .

Subsequently, when the discharge hydraulic pressure further increases as the engine speed increases and reaches P1 in FIG. 7, the hydraulic pressure introduced into the control oil chamber 16 increases, and the cam ring 5 acts on the arm 17. The spring 20 starts to compress and deform and swings eccentrically counterclockwise with the pivot portion 5a as a fulcrum. As a result, the pump capacity is reduced, and the discharge hydraulic pressure rise characteristic is also reduced as shown in FIG. Then, as shown in FIG. 4, the cam ring 5 swings counterclockwise until the lower surface 22a of the first plunger 22 contacts the outer peripheral portion of the upper wall 23a of the second plunger 23. In the state shown in FIG. The first plunger 22 is in contact with the second plunger 23. From this point of time, in addition to the set load W1 of the first coil spring 20, the set load W2 of the second coil spring 21 is applied. Until it reaches P2 (hydraulic pressure P2 in the control oil chamber 16) and overcomes the set load W2, the cam ring 5 cannot swing and is held. Therefore, the discharge hydraulic pressure rises as shown in FIG. 7C as the engine speed rises. However, since the eccentric amount of the cam ring 5 decreases and the pump capacity decreases, It does not have a sudden rise characteristic as shown.

  When the engine speed further increases and the discharge hydraulic pressure becomes equal to or higher than P2, the cam ring 5 is first against the spring force of the set load W2 of the second coil spring 21 via the arm 17, as shown in FIG. The second coil springs 21 and 21 are swung while being compressed and deformed. As the cam ring 5 swings, the pump capacity further decreases and the increase in the discharge hydraulic pressure becomes smaller, and reaches the maximum rotation speed while maintaining the characteristic state shown in FIG.

  FIG. 8 shows the relationship between the displacement of each coil spring 20, 21 or the swing angle of the cam ring 5 and the spring set loads W1, W2. That is, in the initial state from the start of the internal combustion engine to the low rotation, since the spring force of the set load W1 of the first coil spring 20 is applied, it cannot be displaced until the set load W1 is exceeded. When the set load W1 is exceeded, the first coil spring 20 is compressed and displaced, and the load increases. This inclination becomes the spring constant.

  In the position shown in FIG. 4, the set load W2 of the second coil spring 21 becomes discontinuously large, but when the discharge hydraulic pressure exceeds the set load W2, the first and second coil springs 21 and 21 are again compressed and displaced. As the load increases, the number of acting coil springs is two, so the spring constant increases and the slope changes.

  As described above, when the engine speed increases and the discharge hydraulic pressure reaches P1, the cam ring 5 starts to move and suppresses the increase of the discharge hydraulic pressure. However, when the cam ring 5 reaches a predetermined movement amount, the second time is reached. Since the spring force of the coil spring 21 is applied and the spring constant increases, and the spring loads W1 and W2 increase discontinuously, the swing of the cam ring 5 starts again after the discharge hydraulic pressure rises to P2. . That is, the stepwise spring load of the first and second coil springs 20 and 21 acts and the spring characteristic becomes a non-linear state, so that the cam ring 5 has a unique swinging change.

  As described above, in this embodiment, the non-linear characteristic of the spring force of the two coil springs 20 and 21 changes the characteristic of the discharge hydraulic pressure as shown in FIGS. 7A to 7D, and the control hydraulic pressure (solid line) ) Can be made sufficiently close to the required hydraulic pressure (dashed line). As a result, power loss due to unnecessary increase in hydraulic pressure can be sufficiently reduced.

  Further, in this embodiment, since the first and second coil springs 20 and 21 are used, each spring set load can be arbitrarily set according to the change of the discharge hydraulic pressure, which is optimal for the discharge hydraulic pressure. It becomes possible to set the spring force.

  In addition, since the first and second plungers 22 and 23 are provided on the distal end sides of the coil springs 20 and 21, the assembly work is facilitated, and the coil springs 20 and 21 are smooth without being twisted. Can be compressed and expanded. In addition, when the movement amount of each plunger 22 and 23 and the rocking | fluctuation amount of the arm 17 are small, the upper end part 20b of the 1st coil spring 20 may contact | abut directly on the lower surface 17a of the arm 17 without interposing a plunger. Is possible.

  Further, since the lower surface 17a of the arm 17 is formed in an arcuate curved surface, the change of the contact angle and the contact point with the upper surface of the first plunger 22 can be reduced by the swinging of the cam ring 5, thereby It becomes possible to stabilize the displacement of the one coil spring 20. The same effect can be obtained even if the upper surface of the first plunger 22 is formed in an arcuate curved surface shape.

In this embodiment, the lubricating oil discharged from the discharge port through the discharge port 8 is used as an operating source of the valve timing control device in addition to the engine sliding portion. As described above, FIG. The initial discharge hydraulic pressure (region (a)) described in the above section has a good rise, so that, for example, immediately after the engine is started, the responsiveness of the relative rotation phase between the timing sprocket and camshaft to the retarded side or advanced side Can be improved. Further, the variable valve operating device is not limited to the valve timing control device, and is applied to a variable lift mechanism that uses hydraulic pressure as an operating source, for example, the operating angle of the engine valve and the lift amount are variable. Is possible.
[Second Embodiment]
9 to 11 show the second embodiment, and the basic structure of the pump structure and the like is the same as that of the first embodiment, but the configuration of the biasing means, particularly the coil spring, is different.

  That is, the urging means includes an upper first coil spring 25 and a lower second coil spring 26 accommodated in series in the axial direction inside the cylinder body 18, and a tip portion of the first coil spring 25. The cylinder body 18 is interposed between a first plunger 27 disposed between the lower surface 17a of the arm 17 and a lower end portion of the first coil spring 25 and an upper end portion of the second coil spring 26. The second plunger 23 is slidably guided on the inner peripheral surface 18a.

  The first coil spring 25 has a relatively short coil length, and is set to the same spring set load W1 as the first coil spring 20 of the first embodiment.

  The first plunger 27 is formed in a substantially disk shape, and the upper surface thereof is in contact with the arc-shaped curved lower surface 17a of the arm 17, and the upper end portion of the first coil spring 25 is press-fitted into the center of the lower surface. A substantially columnar protrusion 27a is integrally provided. The protrusion 27a ensures straight advanceability when the first coil spring 25 is displaced, and suppresses twisting and falling.

  The second coil spring 26 is formed so that its coil diameter is slightly larger than that of the first coil spring 25, and is set to the same spring set load W2 as the second coil spring 21 of the first embodiment.

  The second plunger 28 is formed in a substantially H-shaped vertical cross section, and has a disk-like base portion 28a at the center, a cylindrical first protruding portion 28b erected on the outer peripheral upper end edge of the base portion 28a, and a base portion 28a. And a cylindrical second projecting portion 28c which is suspended from the lower end edge of the outer periphery of the outer periphery.

  The base portion 28a is elastically sandwiched between the lower ends of the first coil spring 25 and the lower surface of the base portion 28a, while the upper end portion of the second coil spring 26 is elastically contacted with the lower surface thereof. It is in the state that was done. In addition, the upper end edge of the outer peripheral portion of the base portion 28a comes into contact with a stopper protrusion 24b formed on the inner peripheral surface 18a of the cylinder body 18, thereby restricting the maximum extension displacement of the second coil spring 26. ing.

  The first projecting portion 28b is formed so that its axial length H is slightly longer than half the length of the first coil spring 25 in the arrangement state, and its inner peripheral surface is the lower end of the first coil spring 25. The inner diameter is set so as not to disturb the compression / extension displacement while holding the portion. The first protrusion 28b is slidably guided to the inner peripheral surface of the stopper protrusion 24b of the cylinder body 18 at the outer peripheral surface.

  The second projecting portion 28c has an axial length that is substantially the same as that of the first projecting portion 28b, and the inner peripheral surface holds the upper end of the second coil spring 26 while compressing the second projecting portion 28c.・ It is set to an inner diameter that does not hinder extension deformation. The outer peripheral surface of the second projecting portion 28c is also slidably guided to the inner peripheral surface 18a of the medium diameter portion of the cylinder body 18.

  Therefore, according to this embodiment, the operation is almost the same as that of the first embodiment. First, since the pump discharge pressure does not reach P1 from the start of the internal combustion engine to the low rotation range, the arm 17 of the cam ring 5 is The spring force of the first coil spring 25 is pressed against the lower surface 18c of the cylinder body upper end wall 18b, and the operation is stopped (see FIG. 9). At this time, the eccentric amount of the cam ring 5 is the largest, the pump capacity is maximized, the discharge hydraulic pressure rises rapidly with the increase in the engine speed, and the characteristics shown in FIG.

Subsequently, when the discharge hydraulic pressure further increases as the engine speed increases and reaches P1, the hydraulic pressure introduced into the control oil chamber 16 increases, and the cam ring 5 causes the first coil spring 25 acting on the arm 17 to move. It begins to compressively deform and eccentrically swings counterclockwise with the pivot portion 5a as a fulcrum. As a result, the pump capacity is reduced, and the discharge hydraulic pressure rise characteristic is also reduced as shown in FIG. Then, as shown in FIG. 10, the cam ring 5 swings counterclockwise until the outer peripheral portion of the lower surface of the first plunger 27 comes into contact with the upper end edge of the first protruding portion 28b of the second plunger 28. In the state shown, the first plunger 27 is in contact with the first protrusion 28b. However, since the second coil spring 26 is provided with a spring set load W2, the discharge hydraulic pressure is P2 (in the control oil chamber 16). Until the hydraulic pressure P2) overcomes the set load W2, the cam ring 5 cannot be swung and is held. As described above, when the first plunger 27 comes into contact with the second plunger 28, the first coil spring 25 is not further compressed and deformed.

  Accordingly, the discharge hydraulic pressure has a rising characteristic as shown in FIG. 7C as the engine speed rises. However, since the eccentric amount of the cam ring 5 is reduced and the pump capacity is reduced, FIG. It does not have a steep rise characteristic as shown in.

  When the engine speed further increases and the discharge hydraulic pressure becomes equal to or higher than P2, the cam ring 5 has a second resistance against the spring force of the set load W2 of the second coil spring 26 via the arm 17, as shown in FIG. The coil spring 26 swings while being compressed and deformed. As the cam ring 5 swings, the pump capacity further decreases and the increase in the discharge hydraulic pressure becomes smaller, and reaches the maximum rotation speed while maintaining the characteristic state shown in FIG.

  FIG. 12 shows the relationship between the displacement of the coil springs 25 and 26 or the swing angle of the cam ring 5 and the spring set loads W1 and W2. That is, in the initial state from the start of the internal combustion engine to low rotation, since the spring force of the set load W1 of the first coil spring 25 is applied, it cannot be displaced until the set load W1 is exceeded. When the set load W1 is exceeded, the first coil spring 20 is compressed and displaced, and the load increases. This inclination becomes the spring constant.

  From the position shown in FIG. 10, the set load W2 of the second coil spring 26 acts and increases discontinuously. However, when the discharge hydraulic pressure exceeds the set load W2, the second coil spring 26 is compressed and displaced. Although the load increases, the spring member that compresses and deforms is the second coil spring 26, which is different from the first embodiment. Since the spring constant after the set load W2 is determined only by the second coil spring 26, it is possible to set the spring constant in the same manner, and it is optional to increase or decrease it. Since the spring constants of the first and second coil springs 25 and 26 are set to be the same, the spring load characteristic as shown in FIG. 12 is obtained.

  Therefore, as described above, the second embodiment can provide the same effects as those of the first embodiment. In particular, the first and second coil springs 25 are provided by the projections 28b and 28c of the second plunger 28. , 26 are held in the projections 28b, 28c to ensure an upright posture, and the coil springs 25, 26 are tilted or twisted. And the like can be sufficiently prevented.

[Third embodiment]
FIGS. 13 to 16 show the third embodiment, which is also the same as the first embodiment in the basic structure of the pump structure, but the arrangement of the coil springs of the urging means and the configuration of the plunger are the same. It is different.

  In other words, the second coil spring 30 having a small diameter is arranged in parallel inside the first coil spring 29 having a relatively large diameter, and the first coil spring 29 is in contact with the lower surface 17a of the arm 17 at the upper end portion thereof. A plunger 31 is provided, and a second plunger 32 is accommodated in the first plunger 31 so as to be movable up and down.

  The first coil spring 29 has an upper end elastically contacted with the outer periphery of the lower surface of the first plunger 31, and a lower end elastically contacted with the upper surface of the lid portion 19 a of the plug 19 and a predetermined spring set load. W1 is set.

  As shown in FIGS. 14A and 14B, the first plunger 31 is formed in a columnar shape having a step diameter, and the flat upper surface of the upper large-diameter portion 31 a is the lower surface of the arm 17 by the spring force of the first coil spring 29. While being always in elastic contact with 17a, an insertion hole 31c is formed in the lower small-diameter portion 31b in the axial direction from the lower surface side to the inner upper direction. A pair of left and right moving slits 31d and 31d are formed in the vertical direction on both sides of the insertion hole 31c of the small diameter portion 31b. The small-diameter portion 31b has an upper end portion of the second coil spring 30 resiliently supported on the outer peripheral portion of the lower surface, and a protrusion 31e that holds the upper end portion of the second coil spring 30 while positioning it at the center of the lower surface. Is provided.

  The second plunger 32 is integrally formed of a synthetic resin material, is located on the lower end side, and has a disk-like support portion 32a that elastically holds the lower end portion of the second coil spring 30 on the outer peripheral portion of the upper surface. A small-diameter projection 32b that is formed at the center of the upper surface of the support portion 32a and holds the inner peripheral edge of the lower end of the second coil spring 30, and is erected at the center of the upper surface of the projection 32b so as to pass through the insertion hole 31c. A pair of slidable stem portions 32c and 32c is provided. The stem portions 32d and 32d are formed so that the distal end sides can bend and deform inward and outward, and the outer surfaces of the distal end portions engage with the slits 31d and 31d and are slidably guided in the vertical direction. The parts 32d and 32d are provided integrally.

  As described above, the lower end of the second coil spring 30 is held by the upper surface of the support portion 32a, and the upper end of the second coil spring 30 is held by the lower surface of the first plunger 31. And a predetermined spring set load W2 is set.

  Further, as shown in FIG. 13, when the second plunger 32 is separated from the first plunger 31 by the spring force of the second coil spring 30, the lower surface of the support portion 32a is the upper surface of the plug lid portion 19a. Is separated by a predetermined distance S.

  Hereinafter, the operation of the present embodiment will be described. It is basically the same as the first and second embodiments, and the discharge hydraulic pressure characteristics are substantially the same as those in FIG. That is, when the discharge hydraulic pressure rises as the engine speed increases and reaches P1 in FIG. 7, the hydraulic pressure introduced into the control oil chamber 16 increases and the cam ring 5 acts on the arm 17 in the first coil spring 29. Begins to be compressed and deformed, and eccentrically swings counterclockwise with the pivot portion 5a as a fulcrum. As a result, the pump capacity is reduced, and the rise characteristic of the discharge hydraulic pressure is also reduced as shown in the region (a) of FIG. As shown in FIG. 15, the lower surface of the second plunger 32 is in contact with the upper surface of the plug lid portion 19 a, but the second coil spring 30 is not yet compressed and deformed and the spring set load W <b> 2 is applied. Therefore, the cam ring 5 cannot be swung until the discharge hydraulic pressure P2 (the hydraulic pressure P2 in the control oil chamber 16) overcomes the set load W2.

  Accordingly, the discharge hydraulic pressure has a rising characteristic as shown in FIG. 7C as the engine speed rises. However, since the eccentric amount of the cam ring 5 is reduced and the pump capacity is reduced, FIG. It does not have a steep rise characteristic as shown in.

  When the engine speed further rises and the discharge hydraulic pressure becomes P2 or more, the cam ring 5 has springs with set loads W1, W2 of the first and second coil springs 29, 30 via the arm 17, as shown in FIG. The coil springs 20 and 30 swing while compressing and deforming against the force. As the cam ring 5 swings, the pump capacity further decreases and the increase in the discharge hydraulic pressure becomes smaller, and reaches the maximum rotation speed while maintaining the characteristic state shown in FIG. The relationship between the displacements of the coil springs 29 and 30 and the swing angle of the cam ring 5 and the spring set load in this embodiment has the characteristics shown in FIG. 8 as in the first embodiment.

Therefore, in this embodiment, the same effects as those of the above embodiments can be obtained. In particular, the small diameter portion 31b of the first plunger 31 is formed relatively long in the axial direction, and the first coil spring 29 is provided on the outer peripheral side thereof. Since the inner peripheral edge is held, the first coil spring 29 can be effectively prevented from falling or twisting during compression / extension displacement. In addition, the second coil spring 30 also has a shape in which the inner peripheral edges of both end portions are held by the protrusions 31e and 32b, and can prevent inadvertent collapse and twist in displacement.
[Fourth embodiment]
17 to 19 show a fourth embodiment, which also differs from the above embodiments in the configuration of the biasing means.

  The first coil spring 33 and the second coil spring 34 are arranged in parallel with the inner and outer layers, and the outer large first coil spring 33 has an upper end on the upper side of the plunger 35 as in the third embodiment. The lower end portion of the large diameter portion 35a is held on the upper surface of the plug lid portion 19a.

  The inner small second coil spring 34 has a lower end in contact with the upper surface of the plug lid portion 19a, but the upper end is in a free state in the installed state, and the plunger 35 moves downward by a predetermined amount or more. Then, it comes into contact with the lower surface of the plunger 35.

  That is, the plunger 35 is composed of an upper cylindrical large-diameter portion 35 a and a cylindrical small-diameter portion 35 b integrally provided at the center of the lower surface of the large-diameter portion 35 a, and an upper end portion of the first coil spring 33. However, the inner peripheral edge of the upper end portion of the first coil spring 33 is slidably held on the outer peripheral surface of the small diameter portion 35b. Further, the entire axial length of the large diameter portion 35a and the small diameter portion 35b is set to a predetermined length L1.

  The second coil spring 34 is positioned and held by press-fitting the inner peripheral edge of the lower end portion 34a into the outer peripheral surface of the projection 36 projecting from the center of the upper surface of the plug lid portion 19a, and the cam ring 5 shown in FIG. In the maximum eccentric state, the upper end portion 34b is separated from the lower surface of the small diameter portion 35b by a predetermined distance S1 and is in a free length state.

  The spring set load W1 of the first coil spring 33 is set in the same manner as in the first embodiment, but no spring load is applied to the second coil spring 34. Moreover, each coil winding direction is the reverse direction.

  Therefore, according to this embodiment, the characteristic of the discharge hydraulic pressure is as shown in FIG.

  That is, when the discharge hydraulic pressure increases as the engine speed increases and reaches P1 in FIG. 20, the hydraulic pressure introduced into the control oil chamber 16 increases and the cam ring 5 acts on the arm 17 in the first coil spring 33. Begins to be compressed and deformed, and eccentrically swings counterclockwise with the pivot portion 5a as a fulcrum. As a result, the pump capacity is reduced, so that the discharge hydraulic pressure rise characteristic is also reduced as shown in FIG. As shown in FIG. 18, the outer peripheral portion of the lower surface of the small diameter portion 35 b of the plunger 35 contacts the upper surface of the second coil spring 34, but no spring set load is applied to the second coil spring 34. Therefore, the spring constant is increased as much as the number of coil springs is increased to two. Further, the engine speed increases, and the cam ring 5 continues to oscillate due to the increase in hydraulic pressure. However, the increase in the spring constant makes it less likely to oscillate than the region (A) in FIG. The hydraulic pressure rises in the state of region (c) in FIG. 20, and reaches the maximum rotation while the hydraulic pressure increase margin is slightly larger than in region (b) of FIG.

  The relationship between the displacement of the coil springs 33 and 34 and the swing angle of the cam ring 5 and the spring set load of the present embodiment is as shown in FIG. 21 after the compression deformation of the first coil spring 33. When the compression deformation starts, it has a step-up characteristic.

Therefore, in this embodiment, the same operational effects as those of the respective embodiments can be obtained, and the second coil spring 34 is press-fitted and held in advance in the protrusion 36, so that the assembling property is excellent. Become.
[Fifth embodiment]
FIG. 22 shows a fifth embodiment, which is different from the above embodiments in that the coil spring 37 and the plunger 38 of the urging means are each constituted by a single unit. The coil spring 37 is formed by a coil spring of unequal pitch, and the lower end portion 37a is elastically contacted with the upper surface of the plug lid portion 19a, while the upper end portion 37b is elastically contacted with the outer peripheral portion of the lower surface of the plunger 38. The spring constant is set to increase with compressive displacement.

  The plunger 38 is formed in a substantially cylindrical shape as in the fourth embodiment, and an upper end portion 37a of the coil spring 37 is press-fitted into the center of the lower surface to hold the coil spring 37 in a suspended state. 38a is provided integrally. Other configurations are the same as those in the above embodiments.

  Therefore, this embodiment basically has the same operation as that of the fourth embodiment, and the characteristics of the discharge hydraulic pressure are almost the same as those in FIG.

  That is, when the discharge hydraulic pressure increases as the engine speed increases and reaches P2 in FIG. 20, the hydraulic pressure introduced into the control oil chamber 16 increases, and the cam ring 5 compresses the coil spring 37 acting on the arm 17. Only when it begins to deform, it swings eccentrically counterclockwise with the pivot portion 5a as a fulcrum. As a result, the pump capacity is reduced, so that the increase in the discharge hydraulic pressure is also reduced as shown in the region (a) of FIG. Further, the cam ring 5 continues to oscillate as the engine speed increases and the discharge hydraulic pressure increases. However, the spring constant increases due to the compression deformation of the spring, so that it is less likely to oscillate than the region (A) in FIG. In the state of FIG. 20C, the hydraulic pressure rises to the maximum rotation while the hydraulic pressure increase margin is slightly larger than that in the region A of FIG.

Therefore, this embodiment can obtain the same effects as the above-described embodiments, and in particular, since the coil spring 37 and the plunger 38 are single, the manufacturing cost can be reduced compared to the other embodiments. In addition, the size of the apparatus in the radial direction can be made sufficiently small.
[Sixth embodiment]
FIG. 23 shows a sixth embodiment in which the coil spring 39 is tapered so that the diameter gradually increases from the small diameter upper end 39a to the lower end 39b. The portion 39a is elastically contacted with the outer peripheral portion of the lower surface of the plunger 40 and is press-fitted into a protrusion 40a integrally formed at the center of the lower surface of the plunger 40, while the lower end portion 39b is elastically contacted with the upper surface of the plug lid portion 19a. ing. Further, the coil spring 39 is configured to increase as the spring set load is compressed and displaced due to the taper-shaped characteristic. Other configurations are the same as those of the first embodiment.

Therefore, this embodiment can reduce the manufacturing cost and reduce the size of the apparatus in the radial direction as in the fifth embodiment.
[Seventh embodiment]
FIG. 22 shows a seventh embodiment, which is applied to a trochoid pump as a variable displacement pump. The biasing means is the same as the structure of the first embodiment.

  Specifically, this trochoid pump has a pump housing 41 whose one end opening is closed by a cover (not shown) and a substantially central portion of the pump housing 41 to transmit a rotational force from the crankshaft of the engine. A drive shaft 43, an inner rotor 44 and an outer rotor 45 rotatably accommodated in an accommodating recess 42 formed in the pump housing 41, an inner rotor 44 and an outer rotor 45 that are rotatably accommodated in the accommodating recess 42, and And an adjustment ring 46 that rotatably supports the outer peripheral surface of the outer rotor 45 on the peripheral surface.

  The pump housing 41 is integrally formed of an aluminum alloy material. An insertion hole for rotatably supporting the drive shaft 43 is formed at a substantially central position, and the housing recess 42 having a substantially elliptical shape is formed therein. Is formed. Further, the cover is fixed to the front end portion by six bolts, and an adjustment mechanism 47 for urging the adjustment ring 46 in the clockwise direction in the drawing is provided on the right side in FIG.

  The drive shaft 43 is driven to rotate in the direction of the arrow (clockwise) in the figure by receiving a rotational drive force from the crankshaft via a pulley (not shown) provided at one end.

  The inner rotor 44 has a central portion coupled to the drive shaft 43, and six outer teeth 4a formed with a trochoid curve on the outer periphery. The center of the outer rotor 45 is decentered by a predetermined amount e from the center of the inner rotor 44, and seven inner teeth 45a formed by a trochoid curve meshing with the outer teeth 44a are formed on the inner periphery. . Accordingly, a pump chamber 50 is formed in a space surrounded by the tooth tip contact and the tooth bottom of each rotor 44, 45, and the volume of the pump chamber 50 changes as the rotors 44, 45 rotate. Yes.

  Further, a substantially arc-shaped suction chamber 48 is provided at a lower position in FIG. 1 of the pump housing 41, while a discharge chamber 49 is provided at an upper position opposite to the suction chamber 48. Are provided with a suction port 48a and a discharge port 49a communicating with the suction chamber 48 and the discharge chamber 49, respectively. The suction port 48a communicates with the inside of an oil pan provided at the lower end of the engine body and a strainer through a suction passage (not shown) connected to the suction port, while the discharge port 49a is connected to the discharge port. It is connected to the oil gallery of the engine through a discharge passage outside the figure.

  A first seal land portion 51a is formed at a position where the volume of the pump chamber 50 is substantially maximized at the opposite end positions of the suction chamber 48 and the discharge chamber 49 of the pump housing 41, and Second seal land portions 51b are respectively formed in the portions that are the smallest on the opposite side. In the present embodiment, the first seal land portion 51a on the maximum volume side is formed in substantially the same shape as the shape of the pump chamber 50 having the maximum volume.

  The accommodating recess 42 has an angular position of approximately 120 ° in the circumferential direction of the inner peripheral surface thereof, that is, a first curved surface portion 42a substantially corresponding to the maximum volume portion of the pump chamber 50, and a circular shape from the first curved surface portion 42a. Second and third curved surface portions 42b and 42c located at approximately 120 ° in the circumferential direction are each formed by a trochoid curve.

  If the formation procedure of the first to third curved surface portions 42a to 42c is specifically described based on FIGS. 25 and 26, a radius R having an arbitrary length from the center O of the inner rotor 4 is set. A base circle α having a radius 2R / 3 is drawn with respect to the radius R, a virtual rolling circle β having a radius R / 3 rolling on the base circle α is set, and the center O of the base circle α and the virtual circle are set. A line connecting the centers O ′ of the rolling circle β is defined as a reference line J. The reference line J is set so as to pass through the center of the first seal land portion 51a. The discharge chamber 49 and the discharge port 49a are located at the upper position, and the suction chamber 48 and the suction port are located at the lower position. 48a is located.

  On the extended line of the reference line J, a fixed point corresponding to the distance of the eccentric amount e in the radial direction of the outer rotor 45 with respect to the inner rotor 44 from the center O ′ of the virtual rolling circle β in the direction opposite to the center O of the base circle α. Set E.

  A curve represented by the locus of the fixed points E and E ′ when the virtual rolling circle β is rolled without sliding on the base circle α is a trochoidal curve γ.

  When the virtual rolling circle β rolls without slipping to the position θ on the base circle α, the rolling circle β rotates by 2θ, so that the fixed point E has rotated by 3θ with respect to the reference line J.

This can be rewritten as shown in FIG. That is, a point E separated from the center O of the inner rotor 44 by an eccentric amount e is taken, a point T is taken at a position extended by a radius R, and a reference is made in a direction connecting the center point O, the point E and the point T with a straight line. Take line J. From the point E ′ where the point E is rotated by 3θ around the center point O, the locus of the point T ′ with the inclination distance R by θ with respect to the reference line J becomes the trochoid curve γ. Therefore, when the point T is rotated to the point T ′ by the angle θ, the point E is rotated to the point E ′ by the angle 3θ.
That is, when the adjustment ring 46 is rotated by an angle θ, the center X of the adjustment ring 46 is rotated by 3θ.

  A trochoid curve-shaped creation curve created by a circle with a radius r centered on the point T ′ on the trochoid curve γ is separated by γ ′, in other words, a radius length r outward from the point T ′ on the normal line. The curved surface portions 42a to 42c of the accommodating recess 42 are formed as wall surfaces as a curve γ ′ on the trochoid curve represented by the locus of the points.

  In addition, a stopper surface 52 bent in a substantially inverted L shape is continuously formed at a position on the pump rotation direction side of one curved surface portion 42c located on the discharge chamber 49 side.

  On the other hand, as shown in FIG. 27, in the adjustment ring 46, a ring body 46a is formed in a substantially annular shape, and an outer peripheral surface of the outer rotor 45 is supported by an inner peripheral surface 48b of the ring main body 46a so as to be freely slidable. In addition, three slidable contact parts 53 to 55 whose front end surfaces are in slidable contact with the respective curved surface parts 42 a to 42 c of the housing recess 42 are integrally protruded radially outward on the outer periphery.

  The first to third sliding contact portions 53 to 55 are provided at approximately 120 ° in the circumferential direction of the ring main body 46a corresponding to the first to third curved surface portions 42a to 42c, and the center of the inner peripheral surface 46b. Respective tip surfaces 53a to 55a are formed in a semicircular shape having a radius r with the distance from X to R as the center.

  That is, the length of the first sliding contact portion 53 to the distal end surface 53a is set such that the center Ta is set at a distance of the radius Ra from the center X of the inner peripheral surface 46b, and a half of the radius ra from the center Ta. The center Tb is set at a distance from the center X to the radius Rb, and the length from the center X to the tip surface 54a of the second sliding contact portion 54 is a semicircular arc shape having a radius rb. Is formed. Further, the length from the center X to the radius Rc is set as the length of the third sliding contact portion 55 to the distal end surface 21a, and the length is formed in a semicircular arc shape having a radius rc from the center Tc. Yes.

  The first sliding contact portion 53 located on the pump chamber 50 side having the maximum volume is formed with the maximum protrusion amount of the radius Ra, and the second sliding contact portion 54 located on the suction side is a medium radius Rb. The third sliding contact portions 55 that are formed in the protruding amount and are located on the discharge side are formed at the minimum protruding amount with the radius Rc.

  Therefore, the pressure receiving area for the pump hydraulic pressure discharged from the discharge port 14 is larger on the one side surface 53 b of the first sliding contact portion 54 than on the one side surface 54 b of the third sliding contact portion 55.

  Further, when the adjustment ring 46 is rotated in the clockwise direction in FIG. 24 on the side in the rotational direction of the third sliding contact portion 55, the side surface abuts against the stopper surface 52 of the pump housing 41. The restriction protrusion 56 that restricts the rotational movement described above is provided integrally with the ring body 46a.

  In addition, the circumferential range of the first curved surface portion 42a of the accommodating recess 42 described above is set to a predetermined angle (θ−θ1, θ + θ2) in both directions centered on the θ = 0 °, using the e, Ra, and ra. ) And the circumferential range of the second curved surface portion 42b is set from θ = 120 ° to a predetermined angle in both directions counterclockwise using the e, Rb, rb, and further, the third curved surface portion The circumferential range of 42c is set to a predetermined angle in both directions from θ = −120 ° using the e, Rc, and rc.

  Thereby, the front end surfaces 53a to 55a of the respective sliding contact portions 53 to 55 can be brought into sliding contact with the respective curved surface portions 42a to 42c through a minute clearance.

  In addition, an arc-shaped contact portion 57 that rotates the adjustment ring 46 counterclockwise by a plunger, which will be described later, of the adjustment mechanism 47 contacts the position of the second sliding contact portion 54 on the rotation direction side of the adjustment ring 46. Are provided integrally.

  As shown in FIG. 24, the adjusting mechanism 47 includes a cylindrical cylinder body 58 projecting in an inclined manner from the side of the pump housing 41, a plug 59 for closing the open end of the cylinder body 58, and a cylinder body. 58, an inner first coil spring 60 and an outer second coil spring 61, which are inner and outer double compression spring members housed and arranged in parallel inside 58, and a front end portion and a contact portion 57 of the first coil spring 60. And a second plunger that is a contact member that is disposed on the distal end side of the second coil spring 61 and that is slidably guided to the inner peripheral surface of the cylinder body 58. 63.

  The specific configurations of the cylinder body 58 and the plug 59, the first coil spring 60, the second coil spring 61, the first plunger 62, and the second plunger 63 are the same as those in the first embodiment. A specific description is omitted, and only the main configuration will be described.

  The first coil spring 60 is set to a predetermined spring set load W1, and this spring set load W1 is counterclockwise in FIG. 24 when the adjustment ring 46 is at the required oil pressure P1 of the variable valve operating device. It is a load that rotates in the direction.

  The first plunger 62 is formed in a solid columnar shape, and its flat upper surface is always in contact with the contact portion 57, and the tip of the first coil spring 60 is at the center of the lower surface. A protrusion 62a for press-fitting is integrally provided.

  The second coil spring 61 is elastically contacted with the inner surface of the lid portion 59a at the rear end, and elastically contacted with the outer peripheral portion of the lower surface of the upper wall of the second plunger 63, with a predetermined set load. W2 is set. The predetermined set load W2 is a load at which the adjustment ring 46 starts to move when the hydraulic pressure is the required hydraulic pressure P2 during the maximum rotation of the crankshaft.

  Further, the winding directions of the first coil spring 60 and the second coil spring 61 are opposite to each other. Therefore, the both 60 and 61 are not engaged with each other during the compression / extension deformation, and a smooth deformation can be obtained at all times.

  The second plunger 63 is composed of a circular upper wall and a cylindrical portion that hangs down from the outer peripheral lower end edge of the upper wall, and the second coil spring is inserted into an insertion hole formed through the center of the upper wall. 61 is inserted, and the inner diameter thereof is set to a size that does not hinder the compression and deformation of the first coil spring 61.

  The first sliding contact portion 53 of the adjustment ring 46 is positioned on the reference line J by the spring force of the first coil spring 60, and the center X of the ring inner peripheral surface 46b is also on the reference line J. The center is also on the reference line J. That is, the eccentric direction of the outer rotor 45 with respect to the inner rotor 44 is an angle θ = 0 ° in the reference line J direction, and the first seal land portion 51a is also on the reference line J. Accordingly, the positions of the first seal land portion 51a and the maximum volume pump chamber 50 are set to coincide with each other so that the pump discharge amount is maximized.

  Hereinafter, the relationship between the pump discharge pressure and the rotation operation of the adjusting ring 46 in this embodiment will be described with reference to FIGS.

  The space surrounded by the contact points Q1, Q2 between the tip surfaces 53a, 55a of the first and third sliding contact portions 53, 55 of the adjustment ring 46 and the first and third curved surface portions 42a, 42c of the receiving recess 42 is discharged. Since it communicates with the port 49a, the pump discharge pressure acts on the upper outer peripheral portion of the adjustment ring 46 located in the space in the figure, and this pump discharge pressure is a straight line connecting the contact points Q1, Q2. The surface pressure P (arrow) acts vertically, and acts as a resultant force F at the center of the contact points Q1, Q2. Since the center X of the adjustment ring 46 is the same as the center point E of the outer rotor 45, the adjustment ring 46 is displaced from the center O of the inner rotor 4 by the amount of eccentricity e. It acts as a force for rotating counterclockwise in the figure with respect to the center O of the rotor 44.

  At this time, the lengths of the first and third sliding contact portions 53 and 55 of the adjustment ring 46 are (Ra + ra)> (Rc + rc), and the first sliding portion 53 is longer. Since the acting position is away from the center O of the inner rotor 44, a larger counterclockwise rotational force is applied to the adjustment ring 46. Furthermore, as shown in FIG. 24, the pressure receiving area is larger on the one side surface 53 b of the first sliding contact portion 53 than on the one side surface 55 b of the third sliding contact portion 55, so that it is counterclockwise with respect to the adjustment ring 46. This increases the rotational force.

  Thus, the magnitude of the rotational force generated by the pump discharge pressure acting on the adjustment ring 46 can be controlled by making the values of R + r of the three sliding contact portions 53 to 55 different.

  Next, the operation during engine operation (pump operation) will be described.

  First, after the engine is started (after the pump is started), as the drive shaft 43 rotates, the inner rotor 44 and the outer rotor 45 rotate while meshing with the inner and outer teeth 44a and 45a. The pump expands on the chamber 48 side, contracts on the discharge chamber 49 side after passing through the first seal land portion 51a, and changes its volume to perform a pump action.

  Then, when the pump discharge pressure before the pump start or immediately after the start is zero or extremely low, the adjustment ring 46 has the first plunger 62 by the spring force of the first coil spring 60 of the adjustment mechanism 47 as shown in FIG. Since it presses and urges the contact portion 57, it is urged to rotate clockwise. In this state, the restricting protrusion 56 abuts against the stopper surface 52 to restrict further clockwise rotation of the adjustment ring 46.

  In this state, the eccentric direction of the outer rotor 45 with respect to the inner rotor 44 via the adjustment ring 46 coincides with the first seal land portion 51a in the reference line J direction, so the suction chamber 48 side to the discharge chamber 49 side. The volume of the pump chamber 50 is maximum and passes through the first seal land portion 51a, while the volume of the pump chamber 50 from the discharge chamber 49 side to the suction chamber 48 side is minimum and passes through the second seal land portion 51b. Therefore, the pump discharge amount is maximized. For this reason, at the time of low pump rotation, the pump discharge pressure has a characteristic of rapidly rising as shown in FIG.

  Subsequently, when the pump discharge pressure rises as the pump rotation speed increases, the pump discharge pressure acts on the adjustment ring 46 from the discharge port 49a as described above, and the adjustment ring 46 is shown in FIG. Rotating counterclockwise at an angle of, for example, about 15 ° against the spring force of the first coil spring 60 through the sliding contact portions 53 to 55 while leaving the stopper surface 52. When the first coil spring 60 is compressed and deformed and the first plunger 62 comes into contact with the second plunger 63, the adjustment ring 46 is balanced with the pump discharge pressure by the spring load W2 of the second coil spring 61. The rotation is stopped at the selected position.

  As described above, the center point X of the inner circumferential surface 46a, that is, the center point E of the outer rotor 45 rotates about the center point O of the inner rotor 44 with respect to the rotation angle θ of the adjustment ring 46. In the state, the eccentric direction is 45 °. Therefore, the volume of the pump chamber 50 that passes through the first seal land portion 51a is slightly reduced, while the volume of the pump chamber 50 that passes through the second seal land portion 51b is slightly increased, so that the discharge chamber 49 from the suction chamber 48 side. The amount of oil flowing to the side decreases, that is, the pump discharge amount decreases, and the pump discharge pressure rises gently but is suppressed from suddenly rising, as shown in FIGS. .

  Further, the adjustment ring 46 smoothly slides and rotates with respect to the curved surface portions 42a to 42c because the tip surfaces 53a to 55a of the sliding contact portions 53 to 55 are respectively formed in arcuate surfaces.

  Further, when the pump rotational speed is increased, the pump discharge pressure acting on the adjustment ring 46 is further increased. Therefore, as shown in FIG. 30, the adjustment ring 46 is now equipped with the first and second coil springs 60, 61. Rotate further counterclockwise against both set loads W1 and W2 to an angle of about 30 °. For this reason, the center point E of the outer rotor 45 has moved by approximately 90 °, and the eccentric direction with respect to the inner rotor 44 is approximately 90 ° angular position. For this reason, the pump chamber 50 has a volume when passing the first seal land portion 51 a from the suction chamber 48 to the discharge chamber 49 and a volume when passing the second seal land portion 51 b from the discharge chamber 49 to the suction chamber 48. Are substantially equal and the pump discharge is minimized.

  In this way, by rotating the adjustment ring 46 with the pump discharge pressure, the eccentric direction of the inner rotor 44 and the outer rotor 45 can be made variable with respect to the pump housing 41, thereby making the pump discharge amount variable and unnecessary fluid work. Can be reduced. As a result, the power loss as shown in FIG. 7 can be reduced as in the first to third embodiments.

  Furthermore, the adjustment ring 46 rotates against the spring force of the coil springs 60 and 61 of the adjustment mechanism 47 in accordance with the pump discharge pressure. Therefore, when the predetermined discharge pressure is exceeded, the pump capacity is reduced and wasted. It is possible to sufficiently suppress the increase in friction by increasing the hydraulic pressure.

  Since the three slidable contact portions 53 to 55 are provided at intervals of approximately 120 ° in the circumferential direction of the adjustment ring 46, the adjustment ring 46 has three curved surface portions 42 a to 42 c of the pump housing 41 at three points. Since the rotational movement is performed while being in sliding contact, a stable rotational movement can be obtained.

  Moreover, since the pressure receiving areas of the first slidable contact portion 53 and the third slidable contact portion 55 in the rotation direction of the adjustment ring 46 are made different, the pump discharge pressure is efficiently converted to the rotational force of the adjustment ring 46 by a free magnification. Can be converted. As a result, the spring set loads W1, W2 of the coil springs 60, 61 of the adjustment mechanism 47 can be freely set.

It is also possible to form a low friction material on the surfaces of the curved surface portions 42a to 42c or the front end surfaces 53a to 55a of the sliding contact portions 53 to 55, thereby improving the sealing performance and adjusting ring 46. You can get a smoother rotation.
[Eighth embodiment]
FIG. 31 shows an eighth embodiment, which is applied to an external gear pump as a variable displacement pump. This embodiment also has the same basic structure as the urging means. Note that the basic structure of the circumscribed pump is general.

  That is, a pump housing 71 whose both end openings are closed by bars 71a and 71b, a drive shaft 72 that passes through substantially the upper end of the pump housing 71 in the axial direction and is driven to rotate by the crankshaft of the engine, and the pump A drive gear 73 rotatably accommodated in the housing 71 and coupled to the drive shaft 72; and a driven gear 75 rotatably accommodated on the lower inside of the pump housing 71 via a support shaft 74. I have.

  The drive gear 73 has a plurality of teeth 73a formed on the outer periphery and is restricted from moving in the axial direction.

  In the driven gear 75, a plurality of teeth 75a formed on the outer periphery mesh with the teeth 73a of the drive gear 73, and suction and discharge pumping operations are performed by the rotation of the teeth 73a and 75a. It is like that. The driven gear 75 is slidable in the front-rear direction via a pressure receiving member 76 coupled to the front end portion of the support shaft 74 and a first plunger 77 coupled to the rear end portion. It slides in the right direction in the figure by the pump discharge hydraulic pressure supplied to the control oil chamber 82 formed between the front end side cover 71a and the front end surface of the pressure receiving member 76. That is, the pump discharge amount is changed according to the meshing width of the tooth portions 73a and 75a. Further, on the rear end side of the driven gear 75, an urging means is provided to urge the driven gear 75 to the maximum front position so as to obtain a maximum discharge amount (maximum discharge hydraulic pressure).

  This urging means is provided integrally with the pump housing 71 made of an aluminum alloy material, and the cylinder body 78 whose rear end opening is closed by the rear end side cover 71 b and the cylinder body 78 are accommodated in parallel. An inner first coil spring 79 and an outer second coil spring 80, which are inner and outer double compression spring members, the first plunger 77, and the tip end side of the second coil spring 80, are arranged on the cylinder side. The second plunger 81 is slidably guided on the inner peripheral surface 78a of the body 78.

  The first coil spring 79 is formed so that its coil diameter is smaller than that of the second coil spring 21 and arranged on the inner side, and its axial length is longer than that of the second coil spring 80. The front end 79a is in elastic contact with the rear end surface of the first plunger 77, the other end 79b is in elastic contact with the inner surface of the rear end side cover 71b, and the set load is set to W1. This spring set load W1 is a load at which the driven gear 75 starts moving rightward in the figure when the hydraulic pressure is the required hydraulic pressure P1 of the variable valve operating apparatus.

  The first coil spring 79 is held by press-fitting and fitting a front end 79 a into a cylindrical projection 77 a integrally provided at substantially the center of the rear end surface of the first plunger 77.

  The second coil spring 80 has a rear end portion 80b elastically contacting the inner surface of the cover 71b, and a front end portion 80a elastically contacting the outer peripheral portion of the lower surface of the upper wall of the second plunger 81. The load is set to W2. The predetermined set load W2 is a load at which the driven gear 75 starts to move when the hydraulic pressure is the required hydraulic pressure P2 during the maximum rotation of the crankshaft.

  The second plunger 81 slides left and right while being slidably guided on the inner peripheral surface 78a of the cylinder body 78. The maximum leftward movement of the second plunger 81 is such that the outer peripheral edge of the end wall 81a is the front end of the inner peripheral surface 78a. The stopper protrusion 78b formed on the side is abutted and regulated.

  Therefore, this embodiment also has the same effect as each of the embodiments described above. Briefly, the discharge hydraulic pressure in the control oil chamber 82 increases as the pump rotation (engine rotation) increases from the low rotation range. When P1 in FIG. 7 is reached, the hydraulic pressure introduced into the control oil chamber 16 increases, and the driven gear 75 starts to compress and deform the first coil spring 79, and the driven gear 75 moves to the right. As a result, the pump capacity is reduced, and the discharge hydraulic pressure rise characteristic is also reduced as shown in FIG. Then, as shown in FIG. 32, the driven gear 75 moves rightward until the first plunger 77 contacts the outer peripheral portion of the end wall 81 a of the second plunger 81.

  In the state shown in FIG. 32, the first plunger 77 is in contact with the second plunger 81. From this point of time, the set load W2 of the second coil spring 80 is added to the set load W1 of the first coil spring 79. Since the applied hydraulic pressure reaches P2 (the hydraulic pressure P2 in the control oil chamber 16) and overcomes the set load W2, the driven gear 75 cannot move rightward and is held. Accordingly, the discharge hydraulic pressure rises as shown in FIG. 7C as the engine speed rises. However, since the meshing width of the driven gear 75 is reduced and the pump capacity is reduced, FIG. It does not have a sudden rise characteristic as shown.

  When the engine speed further increases and the discharge hydraulic pressure becomes equal to or higher than P2, the driven gear 75 resists the spring force of the set load W2 of the second coil spring 80, as shown in FIG. It moves further to the right while compressing and deforming both springs 79 and 80. As the driven gear 75 moves, the pump capacity is further reduced and the increase in the discharge hydraulic pressure is reduced, and the maximum rotational speed is reached while maintaining the state of the characteristic shown in FIG.

  Therefore, the pump discharge hydraulic pressure characteristics are as shown in FIGS. 7A to 7D, and the control hydraulic pressure (solid line) can be sufficiently close to the required hydraulic pressure (broken line). Power loss due to unnecessary increase in hydraulic pressure can be sufficiently reduced.

  As described above, according to each embodiment of the present invention, power loss due to unnecessary increase in hydraulic pressure can be sufficiently reduced.

  In the first embodiment and the like, since the first and second coil springs are used, each spring set load can be arbitrarily set according to the change in the discharge hydraulic pressure, which is optimal for the discharge hydraulic pressure. It becomes possible to set the spring force.

  Since the first and second plungers are provided at the tip of each coil spring, the assembling work is facilitated and each coil spring can be smoothly displaced without being twisted. Therefore, when the movement amount of each plunger or the swinging amount of the arm is small, the upper end of the first coil spring can be brought into direct contact with the lower surface of the arm.

  Furthermore, since the lower surface of the arm is formed in an arcuate curved surface, the change of the contact angle and the contact point with the upper surface of the first plunger can be reduced by swinging the cam ring. Displacement can be stabilized.

  Moreover, when each coil spring is arrange | positioned in series, it becomes possible to make the magnitude | size of the radial direction of an apparatus small enough.

  Further, in the second embodiment and the like, the protrusions that hold the end portions of the coil springs in the fitted state are provided on the outer peripheral portions of the upper end portion and the lower end portion of the plunger, so that the coil springs fall or twist during displacement. Can be prevented.

  Further, the lubricating oil discharged from the discharge port through the discharge port is used as an operation source of the valve timing control device in addition to the engine sliding portion, but since the initial discharge hydraulic pressure rises well, Immediately after the engine is started, for example, the operation responsiveness to the retard side or the advance side of the relative rotation phase between the timing sprocket and the cam shaft is improved.

  Since the coil winding directions of the first coil spring and the second coil spring are formed opposite to each other, it is possible to prevent the meshing of both at the time of compression / extension displacement.

  The present invention is not limited to the configuration of the above embodiment, and can be applied to, for example, hydraulic equipment other than the internal combustion engine.

DESCRIPTION OF SYMBOLS 1 ... Pump housing 3 ... Drive shaft 4 ... Rotor 5 ... Cam ring 6 ... Vane ring 7 ... Suction port 8 ... Discharge port 11 ... Vane 13 ... Pump chamber 16 ... Control oil chamber 17 ... Arm 17a ... Lower surface 18 ... Cylinder body 18a ... Inner peripheral surface 19 ... Plug 20 ... First coil spring 21 ... Second coil spring 22 ... First plunger 22b ... Projection 23 ... Second plunger 23a ... Upper wall 23b ... Cylindrical part

Claims (4)

A variable displacement pump that supplies oil as an operating source of a variable valve mechanism that controls the operating characteristics of an engine valve by lubrication or hydraulic pressure to each sliding portion of an automobile internal combustion engine,
A rotor that is rotationally driven by the internal combustion engine and has a plurality of slots formed outward;
A plurality of vanes slidably held in the respective slots so as to freely advance and retract;
By accommodating the rotor on the inner periphery, a plurality of hydraulic oil chambers are formed by the rotor and the plurality of vanes, and a cam ring that changes the amount of eccentricity with respect to the rotor by swinging;
A restricting portion for restricting the maximum eccentricity of the cam ring;
A first spring member that constantly urges the cam ring in a direction in which the amount of eccentricity of the cam ring with respect to the rotor is maximized;
When the swing amount of the cam ring is less than a predetermined value, the cam ring is not biased while being held in a set load, and when the swing amount of the cam ring exceeds a predetermined value, the eccentric amount of the cam ring with respect to the rotor is large. A second spring member for urging the cam ring in the direction of
A control oil chamber that moves in a direction in which the amount of eccentricity of the cam ring decreases according to the hydraulic pressure introduced;
With
A variable displacement pump characterized in that the oil sucked into the hydraulic oil chamber by the rotation of the rotor is discharged to each sliding portion of the automobile internal combustion engine and the variable valve mechanism. The variable displacement pump according to claim 1, wherein
The first spring member and the second spring member are constituted by coil springs, and the other coil spring is arranged inside one coil spring so that the two coil springs have different lengths in the arranged state. A variable displacement pump characterized by the above. The variable displacement pump according to claim 2,
The variable displacement pump, wherein the first spring member and the second spring member are formed so that their coil winding directions are opposite to each other. A variable displacement pump that supplies oil as an operating source of a variable valve mechanism that controls the operating characteristics of an engine valve by lubrication or hydraulic pressure to each sliding portion of an automobile internal combustion engine,
A pump structure that discharges the lubricating oil introduced into the plurality of hydraulic oil chambers from the suction portion by the internal combustion engine by a volume change of the hydraulic oil chambers and discharged from the discharge portion;
A variable mechanism that changes the volume of the hydraulic oil chamber that opens to the discharge part by moving a movable member using the discharge hydraulic pressure of the lubricating oil;
Urging means for urging the movable member so that the volume change amount of the hydraulic oil chamber is increased;
With
A set load is applied to the two coil springs constituting the urging means ,
The first coil spring disposed on the movable member side always urges the movable member, and the second coil spring disposed away from the movable member moves the movable member when the movable member moves more than a predetermined amount. A variable displacement pump characterized in that it is energized.

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