JP2655662B2 - Variable displacement pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable displacement pump provided in an automatic transmission of an automobile or the like, and particularly to a measure for controlling a discharge amount.

(Prior Art) In general, in an automatic transmission for an automobile, a variable displacement vane pump is provided at an end of an input shaft so as to supply oil to a transmission mechanism.

As disclosed in Japanese Patent Application Laid-Open No. 59-58185, this variable displacement vane pump has a swing ring that can swing freely by a pivot pin in a housing in which an oil inflow path and an oil outflow path are formed. A rotor is provided eccentrically from the center of the ring, and a plurality of vanes are slidably mounted on the rotor in the radial direction. The pump chamber is urged in the protruding direction so as to contact the inner peripheral surface, and a pump chamber is defined and formed between the swing ring and the rotor by the vanes.

Then, the rotor is eccentrically rotated by the rotation of the engine, and the number of pump chambers is increased or decreased to allow oil to flow into the pump chamber from the inflow path, and to increase the pressure to flow out from the outflow path.
Further, the swing ring is held at a fixed position by a spring interposed between the housing and the housing. In this fixed position state, the oil discharge amount increases as the rotor speed, that is, the engine speed increases. On the other hand, when the rotational speed reaches a predetermined number of revolutions, pressure oil is supplied to a control pressure chamber formed between the outer peripheral surface of the oscillating ring and the inner peripheral surface of the housing, and the ring oscillates to reduce the amount of eccentricity. And the rate of increase or decrease of each of the pump chambers is reduced to keep the oil discharge amount constant.

(Problem to be Solved by the Invention) In the variable displacement vane pump described above, the theoretical discharge amount Qth per one rotation of the engine (one rotation of the rotor) is as shown in the following equation: Qth = 2 · Be (πD−Z · t) cc / min… B: rotor width (cm) e: eccentricity (cm) D: inner diameter of swing ring (cm) Z: number of vanes t: vane width (cm) The actual discharge amount Qreal is the theoretical discharge The quantity Qth is multiplied by the engine speed N to obtain Qreal = Qth · N = 2B · e (πD−Z · t) · Ncc / min. Accordingly, as shown in FIG.
l increases with an increase in the engine speed N. When the engine speed N becomes, for example, 2000 rpm or more, the eccentricity e gradually decreases, the theoretical discharge amount Qth decreases, and the engine speed N decreases. And the actual discharge amount Qreal becomes constant.

On the other hand, the drive torque Tth of the variable displacement vane pump
Is as shown in the following equation: Tth = P · Qth / 2π (kg · cm)... P: pressure As shown in FIG. 8 T1, it decreases as the theoretical discharge amount Qth and the eccentric amount e1 decrease. Will do.

In this variable displacement vane pump, the oil supplied to the transmission mechanism rises in temperature and is supplied to an oil cooler to cool it.In the high engine speed range, the temperature rises particularly sharply, so a large amount of oil is supplied to the oil cooler. It is necessary to supply and cool down.Also, a predetermined amount of cooling is required even in a low engine speed range, and it is necessary to consider lubricity and the like.Therefore, it is necessary to secure constant actual discharge amount Qreal and pressure. is there. Therefore, as shown in FIG. 7 Q1, in the low engine speed region, the actual actual discharge amount Qreal is increased by increasing the rotational speed while the target actual discharge amount Qreal required in the high engine speed region is increased. At A, the actual discharge amount Qreal is set to be constant. Therefore,
Conventionally, since the actual discharge amount Qreal is controlled in two steps of increasing and decreasing Q11 and a fixed range Q12, when the target value A is determined, for example, when the engine speed N is 6500 rpm and the actual discharge amount Qreal is
If it is set to be 40 / min, the fixed area Q12 will be determined.

However, in the middle rotation range of the engine, the actual discharge amount Qreal does not need to reach the target value A, and the engine can be sufficiently cooled with the actual discharge amount Qreal smaller than the target value A. Therefore, for example, there is a problem that the discharge oil is wasted in the low / medium rotation range where the engine speed is 4000 rpm or less, and the drive torque Tth is lost as shown in the equation, and the fuel consumption is reduced. There is a problem that the efficiency is deteriorated and the noise is large because the actual discharge amount Qreal is large. In particular, the low / medium rotation range is a normal range, which has been a factor in reducing fuel efficiency.

The present invention has been made in view of the above point, and by controlling the actual discharge amount of oil in three stages of an initial increase / decrease, a middle period constant region, and a late period increase / decrease, the engine is operated in a low / medium rotation region of the engine. It is an object of the present invention to reduce the actual discharge amount of the fuel cell, improve fuel efficiency and reduce noise.

(Means for Solving the Problems) In order to achieve the above object, the present invention takes the following measures:
First, the discharge amount is increased along with the increase in the rotation speed of the drive shaft until the rotation speed of the drive shaft reaches the predetermined first rotation speed. The discharge amount is kept constant at less than the second rotation speed greater than one rotation speed, and
When the rotation speed of the drive shaft is equal to or higher than the second rotation speed, a control means is provided for controlling the discharge amount to increase again with the increase in the rotation speed.

(Operation) With the above configuration, in the present invention, for example, the drive shaft is rotated by the engine to discharge oil, and the discharged oil is supplied to the transmission mechanism of the automatic transmission. Then, after the drive shaft is started, the discharge amount increases with an increase in the number of revolutions, and is equal to or more than the first number of revolutions, for example, 1250 rp in engine revolutions.
When it becomes more than m, it is controlled to be constant. Thereafter, when the engine speed becomes equal to or more than the second rotation speed, for example, 4000 rpm or more, the discharge amount increases again as the rotation speed increases.

Therefore, the discharge amount in the middle rotation region can be reduced while the discharge amount in the low rotation region and the high rotation region of the drive shaft is sufficiently ensured, so that useless discharge amount can be prevented.

Further, since the discharge amount is reduced, loss of the driving torque can be prevented, and the fuel efficiency can be improved.

Furthermore, since the discharge amount is reduced, noise can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 4, reference numeral 1 denotes an automatic transmission of the engine, which is configured such that a transmission mechanism 12 is provided on an input shaft 11 which is a drive shaft, and the transmission mechanism 12 is provided at an end of the input shaft 11. A variable displacement vane pump 2, which is a variable displacement pump for supplying oil to the pump, is attached.

As shown in FIGS. 1 to 3, the variable displacement vane pump 2 has a housing 3 in which a swing ring 4, a rotor 5, a plurality of (seven in the drawings) vanes 6, and the like are housed. The housing 3 is formed by fixing a cover-side second housing 32 to a passage-side first housing 31. The first housing 31 has a concave portion 31a formed at the center thereof, and an inflow passage 33 and an outflow passage 434 for oil having one end opened in the concave portion 31a.
The upper surface opening 1a is closed by the second housing 32. The end of the input shaft 11 is inserted into a bearing portion 32a formed at the center of the second housing 32.

The oscillating ring 4 is formed in a substantially annular shape,
A semicircular pin hole formed in the outer peripheral surface of the ring 4 and a semicircular pin hole formed in the side surface of the concave portion 31a of the first housing 31 facing the pin hole. The pivoting ring 4 is provided so as to be pivotable about the pivoting pin 41 in the directions of X ₁ and X _{2 in} FIG. Further, on the outer peripheral surface of the oscillating ring 4, a control pressure chamber 71 and a pressing surface 72 of a spring 72, which constitute an oil discharge amount control unit 7 described later, are formed. The control pressure chamber 71 and the pressing surface 72a are formed on both sides of a ring center line Y passing through the center of the pivot pin 41, and the control pressure chamber 71 is formed between the outer peripheral surface of the swing ring 4 and the first housing 31. Are formed by two sealing members 71a and 71b between the side surfaces of the recess 31a. The spring 72 is inserted and arranged in a mounting hole 31b formed by the first housing 31, and is interposed between the bottom surface of the mounting hole 31b and the pressing surface 72a of the swing ring 4 so that the ring 4 biasing the in Figure 1 X ₁ direction.

The rotor 5 is provided within the swing ring 4 with the first and second rotors.
The oscillating ring 4 is housed in a space formed by the housings 31 and 32 and is formed substantially in the shape of a donut plate. The oscillating ring 4 is rotatably disposed at a center O ₂ eccentric with respect to a ring center O ₁ . . Further, the rotor 5 is supported by being fitted through a metal 51a to a boss portion 31c having a central hole 51 protruding substantially at the center of the concave portion 31a of the first housing 31, and is supported by the second housing 32. The input shaft 11 is connected to the fitted input shaft 11. The rotation of the input shaft 11 causes the rotor 5 to partially contact the inner peripheral surface of the oscillating ring 4 so that
It is configured to rotate eccentrically in the direction of FIG. X3. The rotor 5 has a vane insertion groove 52 formed in the outer peripheral surface in the radial direction, and a circumferential groove 53 formed in one side surface (the upper surface in FIG. 3). The plurality of (seven in the drawing) vane insertion grooves 5 are formed at equal intervals in the circumferential direction.

The vane 6 is slidably housed in the insertion groove 52 of the rotor 5, and is provided so as to be able to protrude and retract from the outer peripheral surface of the rotor 5. A ring-shaped backup spring 54 is provided in the circumferential groove 53 of the rotor 5. The inner end of the vane 6 contacts the backup spring 54 and is urged by the spring 54 in a protruding direction from the rotor 15. The tip is formed so as to be in contact with the inner peripheral surface of the swing ring 4. The space formed between the inner peripheral surface of the oscillating ring 4 and the outer peripheral surface of the rotor 5 corresponds to each of the vanes.
The pump chambers 8, 8,... Are formed by being divided into a plurality of pump chambers 8, 6,..., And the inner ends of the inflow path 33 and the outflow path 34 are opened so as to communicate with the respective pump chambers 8. I have.

Further, a flow control valve 73 constituting a part of the control means 7 is provided in the middle of the outflow passage 34, as shown in FIGS. The flow control valve 73 is configured such that a spool 73b and a valve spring 73c are housed in a valve passage 73a formed in the middle of the outflow passage. The suction side and the discharge side of the outflow passage 34 communicate with each other through an inner hole 73d of the spool 73b.When the oil discharge amount increases and the differential pressure between the inside and outside of the spool 73b increases, the spool 73b It moves against the spring force of the spring 73c, and as shown in FIG. 6, the inner hole 73d communicates with the control passage 73f and the drain passage 73g via the small hole 73e of the spool 73b. The control passage 73f is connected to the first housing 3
When the rotation speed of the rotor 5, that is, the engine rotation speed becomes equal to or higher than a predetermined first rotation speed, for example, 1250 rpm or more as shown in FIG. A part of the pressure oil flowing out of the pump chamber 8 is guided to the control pressure chamber 71, and the swing ring 4 is
Of the oil discharge amount (actual discharge amount
Qreal) is constantly controlled.

Further, the first housing 31 is provided with a stopper 74 of the swing ring 4 which is the most characteristic of the present invention. The stopper 74 constitutes a part of the control means 7, so as to restrict the swinging of Figure 1 X ₂ direction in the swing ring 4. Further, the stopper 74 is formed of a round bar and has a spring mounting hole of the first housing 31.
A base end is fixed to the bottom surface of the mounting hole 31b and inserted into the spring 72. The distal end of the stopper 74 is configured to abut on the spring pressing chamber 72a of the swing ring 4, and the second engine speed (rotation speed of the rotor 5) is higher than the first rotation speed M1.
More than the rotation speed, for example, 4000 rpm as shown in FIG.
As described above, the swing ring 4 comes into contact with the stopper 74 to restrict the swing of the swing ring 4, so that the oil discharge amount (actual discharge amount Qreal) increases again.

Next, the operation and effect of the variable displacement vane pump 2 will be described.

First, the input shaft 11 rotates by the rotation of the engine, the rotor 5 will rotate in Fig. 1 X ₃ direction, each vane 6 tip moves in sliding contact with the inner peripheral surface of the swinging ring 4, The pump chamber 8 is increased or decreased by the eccentric rotation of the rotor 5. On the other hand, the oscillating ring 4 is urged in the X1 direction in FIG. ₁ by a spring 72, and oil flows into the pump chamber 8 from the inflow passage 33, and becomes high-pressure oil by contraction of the pump chamber 8. It is discharged from the outflow path 34 and supplied to the transmission mechanism 12. Then, when the engine speed is low, for example, as shown in FIG. 7 M1, at 1250 rpm or less, the spool 73d of the flow control valve 73 has a low discharge oil pressure.
Since it does not move and the small hole 73e is closed, the control pressure chamber 71
Will not be supplied with pressure oil. Therefore, the swinging ring 4 is held in position in which the most moved in the direction X ₁ by the spring force of the spring 72, the eccentricity e of the ring center O ₁ and the rotor center O ₂ is the largest. Then, since the rotor 5 rotates without moving the swing ring 4, the oil discharge amount increases with an increase in the engine speed N based on the above equation (see FIG. 7, Q21).

Subsequently, when the engine speed N becomes 1250 rpm (M
1) The differential pressure between the inside and outside of the spool 73b in the flow control valve 73 increases, and the spool 73b
It moves against the spring force of 3c, and as shown in FIG.
e is opened and the pressure oil flows through the control passage 73f to the control pressure chamber.
Flow into 71. The inflow of the pressure oil, the swinging ring 4 will be rotated about the pivot pin 41 in FIG. 1 X ₂ direction against the spring force of the spring 72. By this rotation, the eccentricity e between the ring center O1 and the rotor center O2 decreases, the rate of increase and decrease of the pump chamber 8 decreases, and the theoretical discharge amount Qt
h decreases based on the above equation. The eccentricity e decreases as the engine speed N increases, as shown in FIG. 8 e2, so that the oil discharge amount (actual discharge amount Qrea
l) is kept constant at, for example, 25 / min, and the initial increase area Q
From 21 will move to the mid-term fixed range Q22.

Next, when the oil discharge amount is kept constant and the engine speed N reaches 4000 rpm (M2), the swing ring 4 comes into contact with the stopper 74, and the rotation of the ring 4 is restricted, so that eccentricity is caused. Since the amount e is kept constant again, the theoretical discharge amount Qth becomes constant, and the oil discharge amount increases again with an increase in the engine speed N, and becomes the late increase region Q23.
The oil discharge amount is, for example, the engine speed N
The target value A of 40 / min is reached at 6500 rpm.

Accordingly, the actual oil discharge amount Qreal is controlled in three stages as shown in FIG. 7 Q2, and a predetermined amount necessary for cooling or the like is secured in the low rotation range and the high rotation range of the engine, and at the same time, the engine In the middle rotation range, the amount of wasteful oil discharge can be reduced.

Since the theoretical oil discharge amount Qth can be reduced early (see M1 in FIG. 7), the driving torque Tth
As shown in FIG. 8 T2, the torque loss can be reduced and the torque loss can be reduced, so that the fuel efficiency can be improved. In particular, the low / medium engine speed range, that is, the initial increase range Q of the actual oil discharge amount Qreal
The constant region 21 and the intermediate constant region Q22 are regular regions. Since torque loss in the regular region can be prevented, the fuel efficiency can be further improved. Further, since the oil discharge amount can be reduced, noise can be reduced.

In the above embodiment, the stopper 74 is
Although the stopper 74 is formed in a cylindrical shape, the stopper 74 may be inserted outside the spring 72.

As another stopper 74 ', as shown by a chain line in FIG. 2, an outwardly concave arc portion 74'a is formed on the side surface of the concave portion 31a in the first housing 31, and a roller or a ball is formed on the arc portion 74'a. May be provided.
Then, the swing ring 4 comes into contact with the stopper 74 'to regulate the swing.

The control means 7 is not limited to the stoppers 74 and 74 ', but may be any as long as it can control the actual discharge amount Qreal in three stages as described above.

Further, although the above embodiment has described the variable displacement vane pump 2, the present invention may be applied to other variable displacement pumps.

Furthermore, the variable displacement pump is an automatic transmission,
Of course, it may be applied to various devices.

(Effect of the Invention) As described above, according to the variable displacement pump of the present invention,
In order to control the discharge amount to increase until the rotation speed of the drive shaft reaches a predetermined first rotation speed, and then to keep it constant, and to increase the discharge amount again when the second rotation speed becomes higher than the first rotation speed. Since it is possible to reduce the fixed amount of the discharge amount as compared with the conventional case, it is necessary to reduce the discharge amount in the middle rotation region while sufficiently securing the discharge amount in the low rotation region and the high rotation region of the drive shaft. And waste of the discharge amount can be prevented.

Further, since the discharge amount is reduced, loss of the driving torque can be prevented, and the fuel efficiency can be improved.

Furthermore, noise can be reduced by reducing the discharge amount.

[Brief description of the drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a plan view of a variable displacement vane pump in which a second housing is omitted, FIG. 2 is an enlarged plan view of the essential parts, and FIG. 3 is FIG. It is sectional drawing in a line. FIG. 4 is a partial cross-sectional side view of the automatic transmission, and FIGS. 5 and 6 are cross-sectional views of the flow control valve when the spool is in a fixed position and when it is moved. FIG. 7 is a characteristic diagram of the actual discharge amount with respect to the rotational speed, and FIG. 8 is a characteristic diagram of the drive torque and the eccentric amount with respect to the rotational speed. 1 .... automatic transmission, 2 .... variable displacement vane pump,
3 ... housing, 4 ... swing ring, 5 ... rotor,
6 Vane, 7 Control means, 11 Input shaft (drive shaft), 71 Control pressure chamber, 72 Spring, 74, 74 '
…… Stopper.

Claims (1)

(57) [Claims] The discharge amount is increased in accordance with an increase in the number of revolutions of the drive shaft until the number of revolutions of the drive shaft reaches a predetermined first number of revolutions. The discharge amount is controlled to be constant below the second rotation speed greater than the first rotation speed, and the discharge amount is increased again as the rotation speed of the drive shaft becomes higher than the second rotation speed. A variable displacement pump characterized by comprising control means for controlling the displacement.