WO2018216418A1

WO2018216418A1 - Variable displacement oil pump

Info

Publication number: WO2018216418A1
Application number: PCT/JP2018/016653
Authority: WO
Inventors: 卓志松任; 川合　正浩; 篤史池田
Original assignee: Ntn株式会社
Priority date: 2017-05-22
Filing date: 2018-04-24
Publication date: 2018-11-29
Also published as: JP2018193974A

Abstract

A variable displacement oil pump 1 is provided with: a rotary shaft 2; pump bodies 3; axial cylinders 3a; pistons 5; a swash plate 6 that applies axial displacement corresponding to a tilt angle with respect to the rotary shaft 2 to each of the pistons 5; and an angle changing mechanism A for changing the tilt angle of the swash plate 6 with respect to the rotary shaft 2, wherein the angle changing mechanism A is formed of an assembly of mechanical components that are integrally rotatable with the rotary shaft 2, and is provided with an axial displacement part B that is continuously displaceable to a prescribed position on one side in the axial direction when the rotational speed of the rotary shaft 2 exceeds a prescribed value, and the tilt angle of the swash plate 6 becomes larger as the axial displacement part B is displaced to one side in the axial direction.

Description

Variable capacity oil pump

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 an oil intake amount and a discharge amount (pump flow rate) increase or decrease according to a 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 rotation range, it is desirable to employ a variable displacement oil pump that can keep the oil discharge amount constant in a rotation range higher than the medium speed rotation range of the engine.

For example, Patent Document 1 below describes a so-called swash plate type variable displacement oil pump capable of adjusting (controlling) the oil discharge amount in accordance with the tilt angle of the swash plate with respect to the rotating shaft. The tilt angle of the swash plate in the oil pump of Patent Document 1 includes a control cylinder having a control piston coupled to the swash plate and a linear displacement sensor for detecting the displacement amount of the control piston, and is detected by the linear displacement sensor. This is controlled by a controller (control unit) that feeds back a displacement amount to control the supply of pressure oil to the control cylinder.

JP 2009-197709 A

In the oil pump of Patent Document 1, the control cylinder constituting the control unit is constituted by a large hydraulic cylinder, and this control cylinder is a cylinder barrel (pump main body) that rotates together with a rotating shaft connected to a drive source. The pump body is disposed in parallel with the pump body including the swash plate and the valve plate, and is bolted to the casing of the pump body. In this case, since the oil pump is increased in size as a whole, the oil pump cannot be used for applications where the entire apparatus including the oil pump is required to be compact, and there is a problem that the target of use is limited.

Further, in the oil pump disclosed in Patent Document 1, a complicated hydraulic circuit or the like is required to control the displacement amount (tilt angle of the swash plate) of the control piston, resulting in an increase in cost of the pump. There is also.

In view of the above circumstances, the main object of the present invention is to provide a variable displacement oil pump that is compact and versatile at low cost.

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 comprises an assembly of possible mechanical parts, and is equipped with an axial displacement portion that can be continuously displaced to a predetermined position on one side in the axial direction when the rotational speed of the rotating shaft exceeds a predetermined value. With displacement to one side Wherein the tilt angle of the plate is increased.

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 Since it changes by the axial direction displacement part which consists of an assembly of the machine parts which can rotate integrally, control circuits, such as a hydraulic circuit and an electric circuit for controlling (adjusting) the tilt angle of a swash plate, can be abbreviate | omitted. 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.

The axial displacement portion capable of exhibiting the above function can be constituted by a centrifugal weight that can be displaced radially outward by a centrifugal force acting in accordance with the rotation of the rotary shaft. At this time, if the variable angle mechanism is provided with a guide member that is fitted to the outer periphery of the pump body and moves the centrifugal weight to one side in the axial direction as the centrifugal weight is displaced radially outward, the guide The centrifugal weight and thus the axial displacement portion can be appropriately displaced to one axial direction by the member (the guide surface thereof).

The axial direction displacement portion may further include a cage that holds centrifugal weights arranged at a plurality of locations in the circumferential direction at predetermined intervals in the circumferential direction. 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 arranged 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 rotary shaft is connected 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 displacement oil pump that is lightweight, compact, and versatile.

3 is a longitudinal sectional view of a variable capacity oil pump according to an embodiment of the present invention, and is a sectional view taken along line XX in 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. It is a top view of the holder | retainer holding a centrifugal weight. FIG. 4B is a cross-sectional view taken along line YY in FIG. 4A. 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 shows 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.

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

In each axial cylinder 3a, a hollow shaft-like piston 5 is disposed 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 cover 31 and the pump body 3 and is fitted around the outer periphery of the rotary shaft 2 (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 2a of the rotating shaft 2 and the large-diameter outer peripheral surface 3d of the pump body 3, the pump body 3 is biased to the other side in the axial direction (the other end surface of the pump body 3 is one end surface of the valve plate 4). A compression coil spring 15 is provided. 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 disposed 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 rotary 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 is disposed on the other axial side of the swash plate 6 (extension portion 6c thereof). A guide member 12 and an axial displacement portion B, and an urging means 20 disposed on one side of the swash plate 6 in the axial direction.

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 the bottomed cylindrical elastic body accommodating member 22 disposed on the inner periphery of the urging means accommodating section 32a and one end opening of 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 between the elastic body housing member 22 and the lid member 33 in an axially compressed state. 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 urging force that the urging means 20 should apply to the swash plate 6. Can be adjusted, for example, by adjusting the axial fixed position of the lid member 33 with respect to the casing 32. By the biasing means 20 having the above configuration, the tilt angle of the swash plate 6 with respect to the rotating shaft 2 is maintained at the initial angle θ ₁ until the rotational speed of the rotating shaft 2 exceeds a predetermined value (for example, 5000 rpm). .

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 the radial direction due to the centrifugal force acting when the rotational speed of the rotary shaft 2 exceeds a predetermined value (for example, 5000 rpm). A cylindrical roller having a mass displaceable on the outside (and one side in the axial direction) is used.

As shown in FIGS. 4A and 4B, the cage 8 has a ring shape 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. A pocket portion 8c for individually holding the centrifugal weight 7 is defined between the

column portions

8b, 8b adjacent in the circumferential direction. 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 (the elastic body housing member 22) 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 other end of the vibration damping means 23 for restricting the minute vibrations in the axial direction of the axial displacement portion B is fixed.

The vibration damping means 23 is accommodated and held in a cylindrical vibration 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. It comprises a compression coil spring 25 as an elastic body interposed between the housing member 24 and the lid member 34 in an axially compressed state, and the other end of the elastic body housing member 24 is the second protrusion of the displacement transmitting member 10. It is fitted and fixed in a recess 10b1 provided in the portion 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 rotating shaft 2 is less than a predetermined value (5000 rpm), the centrifugal force 7 acting on the centrifugal weight 7 disposed on the outer periphery of the pump body 3 is small, so the centrifugal weight 7 is radially outward (and one axial direction). 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 rotary shaft 2 and the pump body 3 (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 valve plate). 4) and the amount of oil discharged outside the oil pump 1 through the discharge port 4b and the discharge hole 31b of the cover 31 do not change.

However, as the number of rotations of the rotating shaft 2 increases, the number of oil suctions and discharges executed 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 in the axial direction is axially moved. It slides continuously on one side, 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 rotating shaft 2 increases, the axial stroke amount of the piston 5 decreases, so that the pump flow rate during one rotation of the rotating shaft 2 decreases. . 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 2 is changed by an axial displacement portion B made up of an assembly of mechanical parts fitted to the outer periphery of the pump body 3 so as to be able to rotate integrally with the pump body 3, so that a hydraulic circuit or an electric circuit for controlling the tilt angle of the swash plate 6 The control circuit (control system) 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 control unit 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. With respect to this point, in the present embodiment, the casing 30 that constitutes the stationary side of the oil pump 1 is provided with damping means 23 that regulates the deflection of the axial displacement portion B, and the end of the damping means 23 is connected to the shaft. Since it is fixed to the directional displacement portion B, it is possible to prevent as much as possible the behavior of the axial displacement portion B and hence the swash plate 6 from becoming unstable. 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. By adopting the mechanical damping means 23 provided with the compression coil spring 25 as an elastic body, 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. it can. 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.

As mentioned above, although the variable displacement oil pump 1 which concerns on one Embodiment of this invention was demonstrated, embodiment of this invention is not restricted 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. The equivalent meanings 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 5a Head 5b Piston shoe 6 Swash plate 7 Centrifugal weight 8 Cage 8a Annular part 8c Pocket 9 Needle roller bearing 10 Displacement transmission member 12 Guide member 12a Guide surface 20 Biasing means 23 Damping means 30 Housing 31 Cover 32 Casing A Deflection mechanism B Axial displacement part θ ₁ Initial angle θ ₂ Maximum tilt angle

Claims

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 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, and imparting axial displacements to the respective pistons in accordance with the tilt angles with respect to the rotating shafts In a variable capacity oil pump comprising a swash plate, and a variable angle mechanism that changes a tilt angle of the swash plate with respect to the rotating 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. A variable displacement oil pump comprising a directional displacement portion, wherein a tilt angle of the swash plate is increased as the axial displacement portion is displaced in one axial direction.
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,
2. The variable displacement oil pump according to claim 1, wherein the variable angle mechanism includes a guide member that guides and moves the centrifugal weight toward one axial side as the centrifugal weight is displaced radially outward.
The variable displacement oil pump according to claim 2, wherein the axial direction displacement portion further includes a cage that holds the centrifugal weights arranged at a plurality of locations in the circumferential direction at predetermined intervals in the circumferential direction.
The angling mechanism is further provided with an urging means 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 4, wherein the rotational drive source is an engine.
The variable displacement oil pump according to any one of claims 1 to 4, wherein the rotational drive source includes an electric motor.
The variable capacity oil pump according to any one of claims 1 to 6, which is used for adjusting a groove width of a pulley constituting the CVT.