JP2018193975A - Variable displacement oil pump - Google Patents

Abstract

To provide a variable displacement oil pump which is light and compact, and can precisely carry out flow rate control, at a low cost.SOLUTION: A variable displacement oil pump 1 includes: pistons 5 which are disposed in axial direction cylinders 3a provided on a pump body 3 integrally rotating with a rotary shaft 2; a swash plate 6 which is disposed so as to tilt to the rotary shaft 2, and applies axial direction displacement according to a tilting angle to the rotary shaft 2 to each piton 5; and a change angle mechanism A chancing the tilting angle of the swash plate 6 to the rotary shaft 2. The change angle mechanism A is made from an assembly of machine components capable of integrally rotating with the rotary shaft 2, and has an axial direction displacement portion B which can displace continuously to a predetermined position on one side in the axial direction when a number of rotations of the rotary shaft 2 exceeds a predetermined value. The tilting angle of the swash plate 6 becomes larger with the displacement of the axial direction displacement portion B to the one side in the axial direction, and in a casing 30 of the pump 1, vibration control means 23 for regulating vibrations when the axial direction displacement portion B displaces in the axial direction is provided.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a variable displacement oil pump, and more particularly to a so-called swash plate type variable displacement oil pump in which the amount of oil sucked and discharged (pump flow rate) increases or decreases according to the tilt angle of a swash plate with respect to a rotating shaft.

  For example, a vane pump or a trochoid pump that sucks and discharges oil by widely rotating a rotor using the rotation of an engine is widely used as an oil pump incorporated in a vehicle's continuously variable transmission (CVT). . However, in these pumps, since the pump flow rate increases as the engine speed increases, the oil discharge amount becomes excessive particularly in the engine speed range above the medium speed engine speed range. Excessive pump power may cause engine power loss, which may contribute to a reduction in automobile fuel consumption. In order to reduce the loss of pump power in the high engine speed range, it is desirable to employ a variable capacity oil pump that can adjust the pump flow rate even in the engine speed range above the medium speed range.

For example, Patent Document 1 below describes a so-called swash plate type variable displacement oil pump in which the pump flow rate increases or decreases in accordance with the tilt angle of the swash plate with respect to the rotating shaft. The tilt angle of the swash plate in this oil pump includes a control cylinder having a control piston connected to the swash plate and a linear displacement sensor for detecting the displacement amount of the control piston, and the displacement amount detected by the linear displacement sensor. Is controlled by a controller (control unit) that controls the supply of pressure oil to the control cylinder. According to this configuration, the following effects can be enjoyed.
(1) Since a mechanical mechanism for detecting the displacement amount of the control piston is not required, the oil pump can be made compact.
(2) Since the displacement amount of the control piston is detected in a non-contact manner by the linear displacement sensor, the durability of the pump is reduced due to variations in detection accuracy and aging of the detection accuracy (unstabilized pump flow control). Can be prevented.

JP 2009-197709 A

  However, in the oil pump of Patent Document 1, the control cylinder constituting the control unit is a large hydraulic cylinder, and this control cylinder includes a cylinder barrel (pump main body), a swash plate, Since the pump body is arranged in parallel with the pump main body provided with a valve plate or the like and is bolted to the casing of the pump main body, it is difficult to say that the entire oil pump is sufficiently light and compact. Therefore, it cannot be used for applications where the entire equipment including the oil pump is required to be lightweight and compact, and there is a problem that the object of use is limited.

  Further, in the oil pump of Patent Document 1, a complicated hydraulic circuit or the like is required to control the displacement amount of the control piston (tilt angle of the swash plate, and hence the pump flow rate). There is also a problem of being invited.

  In view of the above circumstances, an object of the present invention is to provide a low-cost variable displacement oil pump that is lightweight, compact, versatile, and capable of accurately controlling the pump flow rate.

  The present invention devised to achieve the above object includes a rotating shaft coupled to a rotational drive source, a pump body fitted to the outer periphery of the rotating shaft so as to be integrally rotatable with the rotating shaft, and a periphery of the pump body. Axial cylinders provided at a plurality of locations separated in the direction, pistons arranged so as to be able to reciprocate in the respective axial cylinders, and arranged so as to be tiltable with respect to the rotating shafts, with tilt angles with respect to the rotating shafts. In a variable displacement oil pump including a swash plate that imparts a corresponding axial displacement to each piston and a variable angle mechanism that changes a tilt angle of the swash plate with respect to the rotary shaft, the variable angle mechanism rotates integrally with the rotary shaft. It consists of an assembly of possible mechanical parts, and has an axial displacement part that can be displaced continuously to a predetermined position on one side in the axial direction when the rotational speed of the rotating shaft exceeds a predetermined value, and the tilt angle of the swash plate The axial displacement part is displaced to one axial direction Grows as to that, the housing of the variable displacement oil pump, characterized in that the damping means for restricting the deflection of the axial displacement portion.

  According to such a configuration, the axial displacement amount of the piston when the rotary shaft is driven to rotate, that is, the tilt angle of the swash plate that affects the oil intake amount and oil discharge amount (pump flow rate) of the pump is Control circuit such as hydraulic circuit and electric circuit for controlling (adjusting) the tilt angle of the swash plate is omitted because it changes with the axial displacement of the axial displacement part consisting of an assembly of mechanical parts that can rotate integrally. can do. As a result, it is possible to realize a simple and compact variable angle mechanism while having the same function as the controller of the oil pump disclosed in Patent Document 1, thereby reducing the weight, size and cost of the oil pump. Can be realized.

  Further, in the oil pump according to the present invention, the tilt angle of the swash plate that affects the pump flow rate changes with the axial displacement of the axial displacement portion, and thus the behavior of the axial displacement portion (particularly the axial displacement portion). In order to be able to stably exhibit the desired pumping capacity. With regard to this point, in the present invention, the casing constituting the stationary side of the oil pump is provided with damping means for restricting the deflection of the axial displacement portion, so that the behavior of the axial displacement portion, and thus the posture of the swash plate, is improved. It becomes possible to prevent destabilization as much as possible. Thereby, the pump flow rate can be accurately controlled.

  From the above, according to the present invention, it is possible to provide a low-cost variable displacement oil pump that is lightweight, compact and versatile, and that can accurately control the pump flow rate.

  In the oil pump according to the present invention, as described above, since the mechanical variable angle mechanism that omits the hydraulic circuit and the electric circuit is employed, it is preferable to employ the mechanical damping means as the damping means. . Such a vibration damping means can be constituted by, for example, a member provided with an elastic body that can be expanded and contracted in the axial direction within a vibration damping means housing provided in the housing. As the elastic body, for example, a compression coil spring can be employed.

  The damping means accommodating portion can be provided in a partial region in the circumferential direction of the housing. In this case, a compact elastic body, and hence vibration damping means can be employed, which is advantageous in realizing a lightweight and compact oil pump.

  An axial direction displacement part can be comprised by what has a centrifugal weight which can be displaced to the radial direction outer side with the centrifugal force which acts with rotation of a rotating shaft. At this time, if the variable angle mechanism is provided with a guide member that guides and moves the centrifugal weight to the one side in the axial direction as the centrifugal weight is displaced radially outward, the centrifugal weight is guided by the guide member (the guide surface thereof). As a result, the axial direction displacement portion can be appropriately displaced in one axial direction.

  An axial direction displacement part shall further have a holder | retainer which hold | maintains the centrifugal weight arrange | positioned in the circumferential direction several places at the circumferential direction predetermined space | interval. If such a cage is provided, it is possible to transmit the displacement amount of the centrifugal weight in one axial direction to the swash plate via the cage, so that the transmission of the displacement amount to the swash plate is improved. improves.

  The variable angle mechanism may be further provided with a biasing means that is disposed on one side in the axial direction from the swash plate and biases a part of the circumferential direction of the swash plate toward the other side in the axial direction.

  The rotational drive source to which the rotational shaft is coupled can include an engine (automobile engine) or an electric motor. Note that “including an electric motor” is a concept including a case where the motor is composed of only an electric motor and a case where the motor is composed of an electric motor and a reduction gear connected to the output side thereof.

  The variable displacement oil pump according to the present invention can be used, for example, as an oil pump for adjusting the groove width of a pulley (for pulley pressing) constituting a CVT (continuously variable transmission), and also for power assist oil for power steering. It can be used as a pump.

  As described above, according to the present invention, it is possible to provide a low-cost variable-capacity oil pump that is lightweight, compact, versatile, and that can accurately control the pump flow rate.

It is a longitudinal cross-sectional view of the variable capacity oil pump which concerns on one Embodiment of this invention, and is XX arrow sectional drawing of FIG. It is a left view of the variable capacity oil pump shown in FIG. It is a disassembled perspective view of the internal components of a variable capacity oil pump. (A) A figure is a top view of the holder | retainer holding a centrifugal weight, (b) A figure is a YY arrow directional cross-sectional view of (a) figure. It is a longitudinal cross-sectional view of the variable capacity oil pump in the state in which the rotation speed of the rotating shaft exceeds a predetermined value. It is a longitudinal cross-sectional view of the variable capacity oil pump which concerns on other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, “one side in the axial direction” and “the other side in the axial direction” are the right side and the left side, respectively, of FIG.

  FIG. 1 is a longitudinal sectional view of a variable capacity oil pump 1 according to an embodiment of the present invention. The oil pump 1 is a so-called axial piston type swash plate type oil pump, and includes a rotating shaft 2, a pump body 3, a valve plate 4, a swash plate 6, a variable angle mechanism A, and the like. Is housed in a housing 30 constituting the.

  The housing 30 includes a cylindrical casing 32 and a cover 31 that closes an opening (other end) on the other axial side of the casing 32. The cover 31 and the casing 32 are fastening members such as bolts (not shown). Are combined and integrated. The casing 32 has cylindrical urging means accommodating portions 32a and damped means accommodating portions 32b that accommodate urging means 20 and vibration damping means 23 described later, respectively. It is provided at a position where the circumferential phase is different by 180 ° from the accommodating portion 32a.

  The rotating shaft 2 is connected to a rotational drive source (not shown) having a maximum rotational speed of about 10,000 rpm (here, an automobile engine) so as to be able to transmit torque, and is supported by bearings 13 and 14 disposed at two positions spaced apart in the axial direction. The body 30 is rotatably supported. The bearings 13 and 14 are both rolling bearings. In this embodiment, a needle roller bearing is used as the bearing 13 and a ball bearing (deep groove ball bearing) is used as the bearing 14. The outer ring of the bearing 13 is fixed to the cover 31, and the outer ring of the bearing 14 is fixed to the casing 32.

  The rotational torque of the engine as the rotational drive source is transmitted to the rotary shaft 2 via a gear 16 that is fixed in the vicinity of one end (one end) of the rotary shaft 2 on the one axial side. The inner ring of the bearing 14 formed of a ball bearing is engaged with a shoulder surface 2c provided on the rotary shaft 2 in the axial direction, and the gear 16 is mounted on the outer periphery of the rotary shaft 2 and is axially connected to the inner ring of the bearing 14. Are positioned in the axial direction by being clamped from both sides in the axial direction by the cylindrical intermediate member 17 engaged in the above-described manner and the retaining member 18 fixed to the outer periphery of one end of the rotary shaft 2.

  The pump body 3 is fixed to the outer periphery of the rotary shaft 2 so as to be integrally rotatable with the rotary shaft 2. In this embodiment, the spline 2b formed on the outer peripheral surface 2a of the rotary shaft 2 and the spline fitting that fits the spline formed on the inner peripheral surface (small-diameter inner peripheral surface 3c) of the pump body 3 are used. 2 and the pump body 3 can rotate together.

  The pump body 3 has axial cylinders 3a formed at a plurality of locations (9 locations in the present embodiment, see the number of pistons 5 shown in FIG. 3) spaced apart in the circumferential direction. One end of each axial cylinder 3a opens to one end surface of the pump body 3, and the other end of each axial cylinder 3a passes through an axial through hole 3b formed on an extension line of each axial cylinder 3a. Opened to the other end surface of the pump body 3.

  A hollow shaft-like piston 5 is disposed in each axial cylinder 3a so as to be able to reciprocate. A spherical head 5 a is integrally provided at one end of each piston 5, and the head 5 a can swing with respect to a piston shoe 5 b slidably in contact with the inclined surface 6 a of the swash plate 6. It is mated.

  The valve plate 4 has a disc shape and is fitted between the outer periphery of the rotary shaft 2 in a state of being disposed between the cover 31 and the pump body 3 (see JIS B 0401-1; the same applies hereinafter). As shown in FIGS. 2 and 3, the valve plate 4 is provided with an arcuate suction port 4a and a discharge port 4b that are open at both end faces thereof. The suction port 4a communicates with an oil suction hole 31a provided in the cover 31 and an axial cylinder 3a provided in the pump body 3, and the discharge port 4b is axially connected to the oil discharge hole 31b provided in the cover 31. The cylinder 3a is communicated.

  Between the outer peripheral surface 2 a of the rotating shaft 2 and the large-diameter inner peripheral surface 3 d of the pump body 3, the pump body 3 is urged to the other side in the axial direction (the other end surface of the pump body 3 is connected to the valve plate 4. A compression coil spring 15 is provided for pressing against the end face. By providing such a compression coil spring 15, the valve plate 4 is sandwiched between the pump body 3 and the cover 31 so as to be slidable with respect to the pump body 3.

  The swash plate 6 is arranged on one side of the pump body 3 in the axial direction, and is fitted on the outer periphery of the rotary shaft 2 so as to be tiltable (angular displacement) with respect to the rotary shaft 2 (housing 30). As shown in FIGS. 2 and 3, swash plate support portions 6 e and 6 e are provided at two positions spaced apart in the circumferential direction of the swash plate 6, and the swash plate 6 has the swash plate support portion 6 e attached to the casing 32. It is supported by the casing 32 so as to be tiltable with respect to the rotating shaft 2 by fitting into a support hole (not shown) provided. Further, the swash plate 6 is integrally provided with an extension portion 6c extending outward in the radial direction and interposed between an urging means 20 and an axial displacement portion B described later. In this embodiment, the shoe plate 6b is fixed to the swash plate 6, and the other end surface of the shoe plate 6b is a slope 6a in which the piston shoe 5b is slidably contacted. However, the shoe plate 6b may be omitted. .

  The variable angle mechanism A is for changing the inclination angle of the swash plate 6 with respect to the rotation shaft 2 (inclination angle of the inclined surface 6a), and the guide member 12 and the shaft arranged on the other side in the axial direction of the swash plate 6 The direction displacement part B and the biasing means 20 arrange | positioned at the axial direction one side of the swash plate 6 are provided.

  The urging means 20 urges the extension 6 c of the swash plate 6 toward the other side in the axial direction, and is accommodated and held in a cylindrical urging means accommodating portion 32 a provided in the casing 32.

The urging means 20 closes one end opening of the bottomed cylindrical elastic body accommodating member 22 disposed on the inner periphery of the urging means accommodating section 32a and the elastic body accommodating member 22 (the urging means accommodating section 32a). A bottomed cylindrical lid member 33 and a compression coil spring 21 as an elastic body interposed in an axially compressed state between the elastic body housing member 22 and the lid member 33 are provided. A convex portion 22 a is provided at the other end of the elastic body accommodating member 22, and this convex portion 22 a is in contact with one end surface 6 e of the extension portion 6 c of the swash plate 6. The elastic body accommodating member 22 is disposed on the inner periphery of the urging means accommodating portion 32 a so as to be slidable in the axial direction with respect to the casing 32, and the axial direction that the urging means 20 should apply to the swash plate 6. The urging force can be adjusted by adjusting the axial fixed position of the lid member 33 with respect to the casing 32, for example. By the urging means 20 having the above configuration, the tilt angle of the swash plate 6 with respect to the rotating shaft 2 becomes the initial angle θ ₁ until the rotational speed of the rotating shaft 2 exceeds a predetermined value (for example, 5000 rpm, the same applies hereinafter). Retained.

  The guide member 12 and the axial displacement portion B constituting the variable angle mechanism A are disposed between the cover 31 of the housing 30 and the swash plate 6. The axial displacement portion B is composed of an assembly of mechanical parts (a plurality of parts) that can rotate integrally with the rotary shaft 2. Here, the axial displacement portion B is fitted to the outer periphery of the pump body 3 together with the guide member 12 and is arranged inside the housing 30. Has been.

  The guide member 12 is formed in a bowl shape with a metal material, and is fixed to the outer peripheral surface of the pump body 3. As a fixing method of the guide member 12 with respect to the pump body 3, it can select suitably as long as it can control that both move relatively to an axial direction, For example, press injection and key fitting can be employ | adopted. The guide member 12 is provided with a guide surface 12a having a substantially arc-shaped cross section for guiding the radial movement and the axial movement of the centrifugal weight 7 held in a pocket portion 8c of the cage 8 described later at predetermined intervals in the circumferential direction. It has been.

  The axial direction displacement part B is arrange | positioned in the several places (12 places in this embodiment. Refer FIG. 3) spaced apart in the circumferential direction, and it has a diameter between the outer peripheral surface of the pump body 3, and the inner peripheral surface of the casing 32. A centrifugal weight 7 interposed so as to be displaceable in the axial direction and the axial direction, and a cage 8 holding the centrifugal weight 7 are provided. In the present embodiment, the centrifugal weight 7 is a cylindrical roller formed of a metal material in a columnar shape, and can be displaced radially outward by a centrifugal force that acts when the rotational speed of the rotary shaft 2 exceeds a predetermined value. Cylindrical rollers with an appropriate mass are used.

  As shown in FIGS. 4 (a) and 4 (b), the retainer 8 is a ring integrally including an annular portion 8a having a substantially L-shaped cross section and a plurality of column portions 8b arranged at predetermined intervals in the circumferential direction. The pocket part 8c which comprises the shape and hold | maintains the centrifugal weight 7 separately between the pillar parts 8b and 8b adjacent in the circumferential direction is defined. By providing such a cage 8, the plurality of centrifugal weights 7 are held at predetermined intervals in the circumferential direction. The cage 8 is fitted to the outer peripheral surface of the pump body 3 so as to be slidable along the outer peripheral surface of the pump body 3.

  The axial displacement portion B of the present embodiment is disposed adjacent to one side in the axial direction of the needle roller bearing 9 and the needle roller bearing 9 as a thrust bearing disposed adjacent to one side in the axial direction of the cage 8. A ring-shaped displacement transmission member 10 is further provided, and the needle roller bearing 9 is sandwiched between the cage 8 (the annular portion 8a thereof) and the displacement transmission member 10 from both sides in the axial direction. The needle roller bearing 9 and the displacement transmission member 10 are fitted to the outer periphery of the pump body 3 so as to be slidable in the axial direction.

  As shown also in FIG. 3, at the outer peripheral portion of the displacement transmitting member 10, a first protrusion 10a having one end face disposed close to the other end face 6d of the extension 6c of the swash plate 6, and the first protrusion 10a. Is integrally formed with the second protrusion 10b provided at a position where the phase in the circumferential direction is different by 180 °. A recess 10a1 is provided on one end surface of the first protrusion 10a. One end of the recess 10a1 is in contact with the other end surface 6d of the extension 6c of the swash plate 6, and the extension 6c of the swash plate 6 is pivoted. A pressurizing member 11 capable of pressurizing is attached to one side in the direction. Accordingly, the extension 6c of the swash plate 6 is sandwiched between the pressing member 11 and the biasing means 20 from both sides in the axial direction.

  As shown in FIG. 1, a concave portion 10b1 is formed on one end surface of the second protrusion 10b. The concave portion 10b1 has a deflection of the axial displacement portion B (specifically, when the rotary shaft 2 is driven to rotate). The end of the other side in the axial direction of the vibration damping means 23 for restricting the minute vibration in the axial direction of the axial displacement portion B is fixed.

  The damping means 23 is accommodated and held in a cylindrical damping means accommodating portion 32 b provided in the casing 32. The vibration damping means 23 includes a stepped cylindrical elastic body accommodating member 24 disposed on the inner periphery of the vibration damping means accommodating portion 32b, a lid member 34 that closes one end opening of the elastic body accommodating member 24, and an elastic body accommodation. A compression coil spring 25 as an elastic body interposed between the member 24 and the lid member 34 in an axially compressed state, and the other end of the elastic body housing member 24 is a second protrusion of the displacement transmitting member 10 It is fitted and fixed in a recess 10b1 provided in 10b. The elastic body accommodating member 24 is disposed on the inner periphery of the vibration damping means accommodating portion 32b so as to be slidable in the axial direction with respect to the casing 32. By providing the vibration damping means 23 in the above-described manner, the displacement transmission member 10 is prevented from rotating with respect to the rotating shaft 2.

  The operation mode of the oil pump 1 of the present embodiment having the above configuration will be described below.

First, when the rotary shaft 2 is driven to rotate by receiving power from a rotary drive source (not shown), the pump body 3 fitted to the outer periphery of the rotary shaft 2 rotates integrally with the rotary shaft 2. When the rotational speed of the rotary shaft 2 is less than a predetermined value (5000 rpm), the centrifugal weight 7 is not displaced radially outward because the centrifugal force acting on the centrifugal weight 7 arranged on the outer periphery of the pump body 3 is small. As shown in FIG. 1, the contact state between the centrifugal weight 7 and the outer peripheral surface of the pump body 3 is maintained. Therefore, the tilt angle of the swash plate 6 with respect to the rotating shaft 2 does not change from the initial angle θ ₁ shown in FIG. 1, and the axial stroke amount of the piston 5 disposed in the axial cylinder 3a of the pump body 3 also changes. do not do. Accordingly, the pump flow rate during one rotation of the rotating shaft 2 (the amount of oil sucked into the oil pump 1 through the suction hole 31a of the cover 31 and the suction port 4a of the valve plate 4 and the discharge port of the valve plate 4). 4b and the amount of oil discharged to the outside of the oil pump 1 through the discharge hole 31b of the cover 31 does not change.

  However, as the number of rotations of the rotating shaft 2 increases, the number of oil suctions and discharges performed per unit time increases, so the pump flow rate per unit time increases. For this reason, the pump flow rate of the oil pump 1 continuously increases until the rotational speed of the rotary shaft 2 reaches a predetermined value.

On the other hand, when the rotational speed of the rotating shaft 2 exceeds a predetermined value and centrifugal force capable of displacing the centrifugal weights 7 revolving radially outward of the pump body 3 acts on the centrifugal weights 7, The centrifugal weight 7 is displaced radially outward and axially one side so as to be guided by the guide surface 12a of the guide member 12, and the annular portion 8a of the cage 8 is pressurized toward the axially one side. Accordingly, the axial displacement portion B (the cage 8, the needle roller bearing 9, the displacement transmission member 10 and the pressure member 11) fitted to the outer periphery of the pump body 3 so as to be slidable is on one side in the axial direction. The swash plate 6 is slid continuously, and a pressing force corresponding to the sliding movement amount (displacement amount to one axial direction side) of the axial displacement portion B is applied to the extension portion 6c of the swash plate 6. As a result, the swash plate 6 is gradually displaced in the direction in which the tilt angle with respect to the rotation shaft 2 increases, and the swash plate 6 takes the maximum tilt angle θ ₂ (see FIG. 5).

Here, the amount of displacement of the axial displacement portion B in one axial direction (specifically, the amount of displacement possible from the origin position of the axial displacement portion B to one axial direction. In this embodiment, the centrifugal weight 7 is The state in contact with the outer peripheral surface of the pump body 3 is the origin position of the axial displacement portion B.) That is, the maximum displacement angle θ ₂ of the swash plate 6 does not exceed 90 °. To be adjusted. The amount of displacement of the axial displacement portion B in the one axial direction can be adjusted by the mass of the centrifugal weight 7 or the urging force of the urging means 20.

As described above, as the tilt angle of the swash plate 6 with respect to the rotation shaft 2 increases, the axial stroke amount of the piston 5 disposed in the axial cylinder 3a of the pump body 3 decreases. The pump flow rate is reduced while the shaft 2 is rotated once. For this reason, as shown in FIG. 5, when the swash plate 6 has the maximum tilt angle θ ₂ , the pump flow rate during the rotation of the rotating shaft 2 is minimized.

  As described above, in the oil pump 1 according to the present invention, the axial stroke of the piston 5 when the rotary shaft 2 is driven to rotate, that is, the tilt angle of the swash plate 6 that determines the pump flow rate is The hydraulic pressure for controlling the tilt angle of the swash plate 6 changes with the axial displacement of the axial displacement portion B formed of an assembly of mechanical parts fitted to the outer periphery of the pump body 3 so as to rotate integrally with the pump body 3. A control circuit (control system) such as a circuit or an electric circuit can be omitted. Thus, a simple and compact variable angle mechanism A (mechanical variable angle mechanism A) can be realized while having the same function as the controller of the oil pump of Patent Document 1.

  In particular, in the present embodiment, when the rotational speed of the rotary shaft 2 exceeds a predetermined value, the axial displacement portion B is moved to one side in the axial direction by centrifugal force acting on the plurality of centrifugal weights 7 arranged on the outer periphery of the pump body 3. Therefore, the variable angle mechanism A can be greatly simplified. The axial displacement portion B is provided with a cage 8 that holds a plurality of centrifugal weights 7 arranged in the circumferential direction at a predetermined interval in the circumferential direction, and the amount of displacement of the centrifugal weight 7 in one axial direction is the cage. 8 is transmitted to the swash plate 6 via 8, the transmission of displacement to the swash plate 6 is improved, and the tilt angle of the swash plate 6 can be controlled with high accuracy.

  Further, in the oil pump 1 according to the present invention, since the tilt angle of the swash plate 6 that affects the pump flow rate changes with the axial displacement of the axial displacement portion B, the behavior of the axial displacement portion B (particularly, Stabilizing the behavior of the axial displacement portion B when the rotational speed of the rotary shaft 2 exceeds a predetermined value and the axial displacement portion B is displaced to one axial direction stably exhibits the desired pumping capacity. It is important to make it possible (to accurately control the pump flow rate). With regard to this point, in the present invention, the casing 30 that constitutes the stationary side of the oil pump 1 is provided with a damping means 23 that regulates the deflection of the axial displacement portion B, and an end portion (axial direction) of the damping means 23 is provided. Since the other end portion) is fixed to the axial displacement portion B, it is possible to prevent the behavior of the axial displacement portion B and thus the swash plate 6 from becoming unstable as much as possible. Therefore, the pump flow rate can be accurately controlled.

  In the oil pump 1 according to the present invention, as described above, in addition to the adoption of the mechanical variable angle mechanism A in which the hydraulic circuit and the electric circuit are omitted, the oil pump 1 can be expanded and contracted in the axial direction within the vibration damping means accommodating portion 32b. It is a mechanical vibration damping means 23 provided with a compression coil spring 25 as an elastic body, and is a small size housed in a vibration damping means accommodating portion 32b provided in a circumferential partial region of the casing 30 (casing 32). By adopting the vibration damping means 23, it is possible to realize the mechanical oil pump 1 that can control the pump flow rate with high accuracy while being simple and compact. The vibration damping means 23 exhibits a function of preventing the axial displacement portion B from swinging as much as possible when the rotary shaft 2 is rotationally driven (particularly when the axial displacement portion B is displaced in the axial direction). Therefore, as the compression coil spring 25 constituting the vibration damping means 23, a smaller one (having a smaller spring constant) than the compression coil spring 21 constituting the biasing means 20 is used as shown in the drawing. All you need is enough.

  As described above, according to the present invention, it is possible to provide a variable displacement oil pump 1 (mechanical variable displacement oil pump 1) that is lightweight, compact, versatile, and capable of accurately controlling the oil flow rate at a low cost. Can do.

  Since the variable displacement oil pump 1 according to the present invention has the advantages as described above, it can be preferably applied as, for example, an oil pump for adjusting the groove width of a pulley constituting a continuously variable transmission (CVT) of an automobile. it can. This is because the oil pump incorporated in the automobile is preferably as light and compact as possible in order to improve the fuel efficiency of the automobile.

  The variable displacement oil pump 1 according to one embodiment of the present invention has been described above, but the embodiment of the present invention is not limited to this.

  For example, in the embodiment described above, an automobile engine is exemplified as a rotational drive source for rotationally driving the rotary shaft 2, but an electric motor may be adopted as the rotational drive source instead of the automobile engine. Is possible. FIG. 6 shows a rotary drive source 40 having an electric motor 41 and a speed reducer 42 connected to the output side of the electric motor 41. The rotary shaft 2 is connected to the output side of the speed reducer 42 so that torque can be transmitted. 1 is an example of a variable capacity oil pump 1. As the speed reducer 42, for example, a planetary gear speed reducer or a planetary roller speed reducer that is compact and can easily change the speed reduction ratio can be preferably used. The oil pump 1 of this embodiment is substantially the same as the oil pump 1 shown in FIG. 1 and the like except that the rotary shaft 2 having a shape different from the rotary shaft 2 adopted in the oil pump 1 shown in FIG. In general, they have the same configuration and the same operational effects.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Variable capacity oil pump 2 Rotating shaft 3 Pump body 3a Axial cylinder 4 Valve plate 5 Piston 6 Swash plate 7 Centrifugal weight 8 Cage 9 Needle roller bearing 10 Displacement transmission member 12 Guide member 12a Guide surface 20 Biasing means 23 Control Vibration means 25 Compression coil spring (elastic body)
30 Housing 31 Cover 32 Casing 32a Biasing means accommodating portion 32b Damping means accommodating portion A Deflection mechanism B Axial displacement portion θ ₁ Initial angle θ ₂ Maximum tilt angle

Claims (9)

A rotary shaft connected to a rotary drive source, a pump body fitted to the outer periphery of the rotary shaft so as to be rotatable integrally with the rotary shaft, and axial directions provided at a plurality of locations spaced in the circumferential direction of the pump body Cylinders, pistons arranged to be reciprocable in the respective axial cylinders, and arranged to be tiltable with respect to the rotating shafts, and axial displacements corresponding to the tilt angles with respect to the rotating shafts are applied to the pistons. In a variable capacity oil pump comprising: a swash plate to be applied; and a variable angle mechanism that changes a tilt angle of the swash plate with respect to the rotation shaft.
The variable angle mechanism is an assembly of mechanical parts that can rotate integrally with the rotary shaft, and can be continuously displaced to a predetermined position on one side in the axial direction when the rotational speed of the rotary shaft exceeds a predetermined value. Having a directional displacement part,
The tilt angle of the swash plate increases as the axial displacement portion is displaced in one axial direction,
The variable displacement oil pump according to claim 1, wherein a vibration damping means for restricting the deflection of the axial displacement portion is provided in a casing of the variable displacement oil pump.   2. The variable displacement oil pump according to claim 1, wherein the vibration damping means includes an elastic body that can be expanded and contracted in an axial direction within a vibration damping means housing provided in the housing.   The variable displacement oil pump according to claim 2, wherein the vibration damping means accommodating portion is provided in a partial region in the circumferential direction of the casing. The axial direction displacement portion has a centrifugal weight that can be displaced radially outward by a centrifugal force acting with rotation of the rotation shaft,
The variable angle mechanism according to any one of claims 1 to 3, wherein the variable angle mechanism includes a guide member that guides and moves the centrifugal weight to one axial side as the centrifugal weight is displaced radially outward. Capacity oil pump.   5. The variable displacement oil pump according to claim 4, wherein the axial displacement portion further includes a cage that holds the centrifugal weights disposed at a plurality of locations in the circumferential direction at predetermined intervals in the circumferential direction.   6. The variable angle mechanism according to claim 1, further comprising an urging unit that is arranged on one side in the axial direction from the swash plate and urges a part of the circumferential direction of the swash plate toward the other side in the axial direction. A variable displacement oil pump according to claim 1.   The variable displacement oil pump according to any one of claims 1 to 6, wherein the rotational drive source is an engine.   The variable displacement oil pump according to any one of claims 1 to 6, wherein the rotational drive source includes an electric motor.   The variable capacity oil pump according to any one of claims 1 to 8, which is used for adjusting a groove width of a pulley constituting the CVT.

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