JPH04171288A - Variable capacity vane pump - Google Patents

Abstract

PURPOSE:To prevent damage to a clutch pack which supplies discharge hydraulic pressure as line pressure, a brake, and a torque converter by forming a relief valve which drains discharge hydraulic pressure by the movement of a piston when discharge hydraulic pressure becomes higher than relief pressure to be set according to prescribed supply hydraulic pressure. CONSTITUTION:An electromagnetic valve 31 adjusts supply hydraulic pressure Ps, based on the result detected by a pressure sensor 32, and outputs control hydraulic pressure Pc. According to the control hydraulic pressure Pc, eccentric amounts of a cam ring 21 and a rotor 22 are changed to control discharge hydraulic pressure Pa. A relief valve 41 introduces supply hydraulic pressure Ps through a passage 44 and introduces discharge hydraulic pressure Pa in the hydraulic pressure passage 30 through a passage 45, and faces them each other through a piston 42. When a force applied to the piston 42 by discharge hydraulic pressure Pa introduced in the relief valve 41 becomes higher than the force applied to the piston 42 by supply hydraulic pressure Ps and a spring 43, the piston 42 moves in the right direction shown in the figure, and discharge hydraulic pressure Pa is drained from a passage 46 to an oil pan T through ports 41a and 41b.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a variable displacement vane pump, and particularly to a variable displacement vane pump that supplies hydraulic pressure to a hydraulic circuit such as an automatic transmission of a vehicle.

(Prior Art) As a conventional variable capacity vane pump, for example, there is U.S. Pat.
Shown as shown.

In FIG. 4, a rotor 2 housed in a freely eccentric cam ring l is provided with a plurality of vanes 3 that can appear and retract in radial directions, and the vanes 3 are in sliding contact with the inner peripheral surface of the cam ring 1. A working chamber 4 defined by the cam ring 1 and the rotor 2 is divided into a plurality of chambers. According to the rotation of the rotor 2, hydraulic oil is sucked into the working chamber 4 from the suction hole 1a, and hydraulic oil having a predetermined discharge oil pressure is discharged from the discharge hole 1b. The cam ring 1 is biased by a spring 5 in a direction perpendicular to the axis, and is biased by a control piston 6 in a direction opposite to the direction in which the spring 5 is biased. The amount of eccentricity is changed, and the amount of eccentricity is maintained at a predetermined value by the spring 5.

The control piston 6 operates in accordance with the control oil pressure pc to displace the cam ring 1.
is supplied from a controlled hydraulic pressure supply means 7 consisting of a solenoid valve. The control oil pressure supply means 7 adjusts the supply pressure Ps according to the control signal from the electric control means 8 to provide the control oil pressure P.
Generate c.

The electric control means 8 includes a pressure sensor 9 that detects the discharge oil pressure of hydraulic oil discharged from the working chamber 4, a throttle opening detection sensor 10, a vehicle speed detection sensor 11, and an oil temperature detection sensor 1.
2, and sends a control signal to the control oil pressure supply means 7 so that the discharge oil pressure detected by the pressure sensor 9 approaches the target working oil pressure value calculated from the detection results from the other sensors 10, 11, and 12. Output. In addition, the supply oil pressure Ps
The control oil pressure Pc is always maintained at a constant pressure to ensure stability.

(Problem to be Solved by the Invention) However, in such a conventional variable displacement vane pump, the control hydraulic pressure Pc for controlling the operation of the control piston 6 is generated by the control hydraulic pressure supply means 7 consisting of a solenoid valve. , when the electronic circuit of the electric control means 8 or the like breaks down due to disconnection of the solenoid terminal of the control hydraulic pressure supply means 7 or an error in the detection of each sensor 9 to 12, the hydraulic pressure acting on the control piston 6 becomes zero. , and the vane pump is driven at maximum eccentricity. As a result, the discharge pressure of the hydraulic oil becomes excessive, and excessive stress is applied to, for example, clutch packs, brakes, or torque converter parts that supply this discharged hydraulic pressure as line pressure, so it is important to prevent damage to these parts. From my point of view, it was insufficient. In addition, in variable capacity vane pumps for conventional automatic transmission units (hereinafter referred to as A/T units) other than those previously filed by the present applicant as mentioned above, hydraulic oil pressure is generally controlled by a regulator valve. Since the system was controlled, there was no need to consider failure of the electronic circuit, and a simple small-flow ball-type relief valve was installed to prevent the hydraulic pressure in the pump body from becoming abnormally high in relation to the hydraulic pressure control valve. It was just that.

Therefore, the present invention controls the solenoid valve, for example, by draining the discharge hydraulic pressure by the relief valve when the discharge hydraulic pressure becomes higher than the relief pressure set according to a predetermined supply hydraulic pressure supplied to the solenoid valve. Even if the electronic circuit for the
The objective is to prevent damage to clutch packs, brakes, or torque converter components that supply this discharged hydraulic pressure as line pressure.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a suction hole for sucking hydraulic oil, a discharge hole for discharging hydraulic oil, a cam ring whose eccentricity can be freely changed, and a suction hole. and a rotor that defines, together with a cam ring, a working chamber that can communicate with the discharge hole; A plurality of vanes divided into chambers, a pressure sensor that detects the discharge hydraulic pressure of hydraulic oil discharged from the working chamber through the discharge hole,
A variable capacity vane pump that includes a solenoid valve that regulates a predetermined supply hydraulic pressure based on the detection result of a pressure sensor and outputs a control hydraulic pressure, and that changes the amount of eccentricity of a cam ring according to the control hydraulic pressure output from the solenoid valve, The predetermined supply hydraulic pressure and discharge hydraulic pressure are introduced and made to face each other via a piston, and when the discharge hydraulic pressure becomes larger than a relief pressure set according to the predetermined supply hydraulic pressure, the discharge hydraulic pressure is drained by moving the piston. The invention is characterized in that a relief valve is provided, and the discharge hydraulic pressure is drained into the vicinity of the suction port of the suction hole by the relief valve. A variable hydraulic pressure output means is connected and outputs a hydraulic pressure corresponding to the selected range of the automatic transmission of the vehicle as the supplied hydraulic pressure, and the output hydraulic pressure in a range other than the forward range is smaller than the output hydraulic pressure in the reverse range. A further feature is that the variable hydraulic pressure output means outputs hydraulic pressure so that the relief pressure in the reverse range is higher than the relief pressure in the forward range.

(Function) In the present invention, for example, when the electronic circuit that controls the operation of the solenoid valve malfunctions and the vane pump continues to be driven in the maximum eccentric state, and the discharge pressure of hydraulic oil becomes excessive, that is, the discharge When the oil pressure becomes greater than the relief pressure set according to the predetermined supply oil pressure, the relief valve drains the delivery oil pressure. Therefore, the delivery oil pressure is prevented from becoming excessive, and for example, This prevents damage to components supplied as line pressure, such as clutch punctures and brake or torque converter components.

Furthermore, when the discharge hydraulic pressure is drained near the suction port of the suction hole, negative pressure is prevented from forming near the suction port of the suction hole when the pump rotates at high speed and the discharge amount is high, and cavitation is prevented. Therefore, the durability of the pump is improved.

Furthermore, if a variable hydraulic output means is provided so that the relief pressure in the reverse range is higher than the relief pressure in the forward range, for example, the maximum pressure of the clutch pack that acts only in the drive range is reduced, and the clutch pack's maximum pressure is reduced. It becomes possible to reduce the weight and size.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a diagram showing a first embodiment of a variable displacement vane pump according to the present invention, and is an example applied to a pump that supplies hydraulic pressure to a hydraulic circuit of a vehicle.

First, the configuration will be explained.

In FIG. 1, 21 is a cam ring installed in the pump cover C, and the pump housing has a suction hole 21a for sucking in hydraulic oil and a discharge hole 21b for discharging it. Further, a rotor 22 is housed within the cam ring 21, and the rotor 22 is connected to an input shaft 23 connected to a drive source (not shown). cam ring 21
is eccentric by a predetermined amount with respect to the rotor 22, and the working chamber 24, which can communicate with the suction hole 21a and the discharge hole 21b, is connected to the cam ring 2.
It is defined together with 1.

Further, a plurality of vanes 25 are fitted into the rotor 22 so as to be able to move in and out in the radial direction of the rotor 22, and the vanes 25 are in sliding contact with the inner circumferential surface of the cam ring 21 to divide the working chamber 24 into a plurality of chambers. Divide into. When the volume of each chamber in the working chamber 24 increases or decreases sequentially due to the rotation of the rotor 22, hydraulic oil is sucked into the working chamber 24 from the oil pan T through the suction hole 21a, and discharge oil pressure is discharged from the working chamber 24 through the discharge hole 21b. Hydraulic oil having Pa is discharged. The discharge oil pressure Pa is supplied as a line oil pressure to a hydraulic circuit such as an A/T unit of the vehicle via a hydraulic passage 30, and the discharge oil pressure of the hydraulic oil is detected by a pressure sensor 32.

On the other hand, the cam ring 21 is supported by a support member 26 fixed to the pump cover C so as to be swingable in the direction perpendicular to the axis (vertical direction in FIG. 1) in which the amount of eccentricity with respect to the rotor 22 changes. A spring 27 interposed between the cam rings 21 is biased upward in the figure to keep the eccentricity constant. 28 is a control piston that defines a control chamber 29 between it and the pump cover C, and the control piston 28 is connected to the cam ring 21.
is engaged in. The control piston 28 receives the control hydraulic pressure Pc supplied to the control chamber 29 and swings downward in the figure around the fulcrum 2B'a held by the pump cover 〇, urging the cam ring 21 in the opposite direction to the spring 27. The discharge oil pressure Pa is controlled by changing the amount of eccentricity between the cam ring 21 and the rotor 22 in accordance with the control oil pressure Pc. The control hydraulic pressure Pc is introduced from the solenoid valve 31, and the solenoid valve 31 regulates the supply hydraulic pressure Ps based on the detection result of the pressure sensor 32 and outputs the control hydraulic pressure Pc. In detail, the operation of the solenoid valve 31 is controlled by the pressure sensor 3.
The control unit 33 is configured to include a microcomputer, etc., and executes the hydraulic control program stored inside, and outputs the output signal P of the pressure sensor 32.
A throttle opening signal TVO from a throttle sensor 34 that detects the opening of a throttle valve (not shown); a vehicle speed signal V from a vehicle speed sensor 35 that detects the speed of the vehicle; a signal from an oil temperature sensor 36 that detects the temperature of hydraulic oil. Based on To, the speed change command signal, etc., the ratio of energization time for each predetermined minute time, that is, the duty ratio is calculated, and a voltage pulse corresponding to the duty ratio is output to the solenoid valve 31.

Then, in the solenoid valve 3, the solenoid coil 31a is excited by this voltage pulse, and the ball 31b is separated from the passage 31d against the biasing force of the return spring 31c, and the supply hydraulic pressure Ps flowing into the passage 31d is transferred to the passage 31e and the passage. 31f to a feedback passage 37 communicating with the control chamber 29. In addition, the solenoid valve 31
When the solenoid coil 31a is not excited, the return spring 31c urges the ball valve 31b in the valve closing direction to cut off communication between the passage 31d and the passages 31e and 31f. On the other hand, an orifice 38 is provided on the feedback passage 37, and the solenoid valve 31 supplies the control oil pressure Pc to the control chamber 29 according to the duty ratio through the orifice 38. Note that 39 is a feedback accumulator piston that absorbs pulsations that occur in the feed bank oil pressure (control oil pressure Pc) in the feed bank passage 37 during gear changes and the like.

Here, 41 is a relief valve, and the relief valve 41 has a piston 42 and a spring 43. The relief valve 41 introduces the supply hydraulic pressure Ps through the passage 44 and the discharge hydraulic pressure Pa of the hydraulic passage 30 through the passage 45, and these hydraulic pressures are made to oppose each other via the piston 42. That is, the discharge oil pressure Pa and the supply oil pressure Ps act on the piston 42 as opposing pressures. Discharge oil pressure Pa introduced into the relief valve 41
When the force acting on the piston 42 of the spring 43 becomes larger than the supply oil pressure Ps and the force acting on the piston 42 of the spring 43, the piston 42 moves to the right in FIG. 4
Drained from 6 to oil pan T. On the other hand, passage 44
can communicate with the hydraulic passage 30 and the leak port 48 via the pilot valve 47. The pilot valve 47 has a piston 49 and a spring 50. The piston 49 is pushed to the right in FIG. 1 by the supplied hydraulic pressure Ps, and is pushed to the left in the drawing by the spring 50. When the piston 49 moves to the right, communication between the passage 44 and the hydraulic passage 30 is cut off, and the port 48 is brought into communication, so that the pressure in the passage 44 is reduced.

On the other hand, when the piston 47 moves to the left, the passage 44 and the hydraulic passage 30 are communicated with each other, and the communication with the port 48 is cut off, so that the pressure in the passage 44 increases. Therefore, the supply oil pressure Ps introduced into the relief valve 41 via the passage 44 is regulated to a constant oil pressure that is uniquely determined by the spring load of the spring 50. That is, the timing of draining by the relief valve 41 described above is such that the discharge oil pressure Pa introduced into the relief valve 41 is set according to the supply oil pressure Ps, that is, greater than the relief pressure set by the supply oil pressure Ps and the spring load of the spring 43. This relief pressure is determined by the spring load of the spring 50, and is determined by the maximum oil pressure in the control range by the control unit 33, from 0 to 4 kg.
/cm". With this setting, there is no drain from the relief valve 41 during normal use, and the pump discharge amount and driving torque can be minimized.

In this embodiment, the control hydraulic pressure Pc is applied to the cam ring 21 via the control piston 28, but by directly sealing the cam ring 21 and the casing, the control hydraulic pressure Pc is applied directly to the cam ring 21. You can also do this.

According to the above configuration, the discharge oil pressure Pa is equal to the supply oil pressure P.
Since the relief valve 41 is provided to drain the discharge hydraulic pressure Pa when the relief pressure becomes larger than the relief pressure set according to When a failure occurs and the hydraulic pressure in the feedback passage 37 is turned off, the vane pump is driven in the maximum eccentric state and the discharge hydraulic pressure Pa of the hydraulic oil becomes excessive, that is, the discharge hydraulic pressure Pa is thicker than the above-mentioned relief pressure ( When this happens, the relief valve 41 can drain the discharge oil pressure Pa.

Therefore, it is possible to prevent the discharge oil pressure Pa from becoming excessive, and it is possible to prevent damage to components to which this discharge oil pressure Pa is supplied as line pressure, such as the treadmill, brakes, or torque converter components.

In addition, since the supply oil pressure Pa supplied to the solenoid valve 31 is constantly regulated to a constant pressure by the pilot valve 47, a highly accurate control oil pressure Pc can be supplied to the control chamber 29, and the amount of eccentricity of the pump can be increased. Can be controlled with precision.

Furthermore, as the oil pressure supplied to the relief valve 41 to set the relief pressure, the supply oil pressure PS, which is constantly regulated by the pilot valve 47 as described above, is used, improving the accuracy of setting the relief pressure. can do. As a result, the pressure resistance of the clutch etc. can also be set low.

Furthermore, since the hydraulic pressure opposite to the discharge hydraulic pressure Pa is the supply hydraulic pressure Ps that is constantly regulated, the spring 4
The space of 3 can be reduced, and miniaturization can be achieved.

Furthermore, by providing the relief valve 41,
A large flow rate can be drained in a small space.

FIG. 2 is a diagram showing a second embodiment of the variable displacement vane pump according to the present invention. In this second embodiment, a pilot valve 51 is used instead of the pilot valve 47 in FIG.
has been established. In FIG. 2, the same members as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted.

In FIG. 2, the pilot valve 51 is connected to the hydraulic passage 30.
In addition to the passage 44, it is connected to a manual valve 52 and a reverse valve 53. Here, when the A/T is switched to the reverse range (R), the reverse hydraulic pressure Pr is transferred from the manual valve 52 to the reverse valve 53.
is supplied. This reverse oil pressure Pr causes the piston 54 of the reverse valve 53 to move to the right in FIG.
Stop the oil supply by s. In the forward range, the piston 54 of the reverse valve 53 moves to the left due to the biasing force of the spring 55, and the piston 54 of the reverse valve 53 moves to the left.
Ensure oil supply to a. On the other hand, pilot valve 5
The supply hydraulic pressure Ps is always introduced into the port 1) 51b.

Therefore, in the reverse range, the supply hydraulic pressure Ps is introduced only from the port 51b, and in the forward range, the supply hydraulic pressure Ps is introduced from the port 51a.
The supply hydraulic pressure PS is introduced from both the hydraulic pressure and the hydraulic pressure 51b. In other words, the pilot valve 5 is
The rightward force due to the supply oil pressure Ps acting on the piston 56 of No. 1 is smaller than the force in the forward range. In addition, the pilot valve 51 is connected to the piston 56 depending on the range.
The valve 47 functions in the same manner as the pilot valve 47 described above, except that the force pressing the valve in the rightward direction changes, and regulates the supply hydraulic pressure Ps. Therefore, the supply oil pressure Ps supplied to the relief valve 41 in the forward range can be adjusted to be lower than the oil pressure in the reverse range, and the relief pressure in the forward range is set lower than the relief pressure in the reverse range. be able to. That is, the pilot valve 51, the manual valve 52, and the reverse valve 53 are connected to the relief valve 41, and constitute a variable hydraulic pressure output means that outputs a hydraulic pressure corresponding to the selected range of the automatic transmission of the vehicle as a supplied hydraulic pressure, and the variable hydraulic pressure The output means outputs hydraulic pressure so that the output hydraulic pressure in the forward range is smaller than the output hydraulic pressure in the reverse range, and the relief pressure in the reverse range is made higher than the relief pressure in the forward range.

According to the second embodiment described above, since the relief pressure in the reverse range is set higher than the release pressure in the forward range, in addition to the effect of the first embodiment, the drive range (D) It is possible to reduce the maximum pressure of the clutch pack that acts solely on the clutch pack, and as a result, the clutch pack can be made lighter and smaller.

FIG. 3 is a diagram showing a third embodiment of the variable displacement vane pump according to the present invention, and in this third embodiment, a passage 61 is provided in place of the passage 46 in FIG. In addition, the third
In the figures, the same members as those of the first embodiment shown in FIG. 1 are given the same reference numerals, and their explanations will be omitted.

In FIG. 3, the passage 61 does not introduce the drained hydraulic oil into the oil pan T, but instead connects the suction hole 21 of the cam ring 21.
It is provided so as to lead directly to the vicinity of the suction port of (a). That is, the discharge oil pressure Pa is drained by the relief valve 41 to the vicinity of the suction port of the suction hole 21a of the cam ring 21.

According to the third embodiment, since the relief valve 41 drains the discharge hydraulic pressure Pa near the suction port of the suction hole 21a, the pressure near the suction port of the suction hole 21a is Negative pressure can be prevented, cavitation can be prevented and cavitation noise can be reduced, and the durability of the pump itself can be improved.

Moreover, by having the above-described configuration, it becomes possible to incorporate the relief valve 41 into the pump body,
The control valve can be downsized.

It should be noted that also in the above-mentioned second embodiment shown in FIG.
As in the third embodiment shown in the figure, the discharge hydraulic pressure may be drained near the suction port of the suction hole 21a by the relief valve 41.

(Effects) According to the present invention, when the discharge hydraulic pressure becomes higher than the relief pressure set according to the predetermined supply hydraulic pressure, the discharge hydraulic pressure is drained by the relief valve, so that, for example, the operation of the solenoid valve is controlled. When the electronic circuit malfunctions and the vane pump is driven at maximum eccentricity and the discharge pressure of the hydraulic oil becomes excessively high, that is, when the discharge hydraulic pressure becomes greater than the above-mentioned relief pressure, the relief valve drains the discharge hydraulic pressure. be able to. Therefore, it is possible to prevent the discharge hydraulic pressure from becoming excessively high, and it is possible to prevent damage to components such as clutch packs, brakes, or torque converter components to which this discharge hydraulic pressure is supplied as line pressure.

In addition, if the relief valve is used to drain the discharge hydraulic pressure near the suction port of the cam ring's suction hole, this will prevent negative pressure from forming near the suction port of the suction hole when the pump is running at high speeds and has a high discharge amount. This can prevent cavitation and reduce cavitation noise, improving the durability of the pump itself.Also, the relief valve can be built into the pump body.

In addition, if the relief pressure in the reverse range is made higher than the relief pressure in the forward range, for example, the maximum pressure of the clutch pack that acts only in the drive range (D) can be reduced, and as a result, the clutch pack can be made lighter and smaller.

[Brief explanation of the drawing]

FIG. 1 is a schematic overall view of a first embodiment of a variable capacity vane pump according to the present invention, FIG. 2 is a schematic overall view of a second embodiment of a variable capacity vane pump according to the present invention, and FIG. 3 is a schematic overall view of a second embodiment of a variable capacity vane pump according to the present invention. FIG. 4 is a schematic overall view of a third embodiment of a variable capacity vane pump, and FIG. 4 is a general schematic view of a conventional variable capacity vane pump. 21...Cam ring, 21a...Suction hole, 21b...Discharge hole, 22...Rotor, 24...Working chamber, 25. ... Vane, 31 ... Solenoid valve, 32 ... Pressure sensor, 41 ... Relief valve, 42 ... Piston,

Claims (3)

[Claims] (1) A suction hole that sucks in hydraulic oil, a discharge hole that discharges hydraulic oil, a cam ring whose eccentricity can be freely changed, and a rotor that, together with the cam ring, defines a working chamber that can communicate with the suction hole and the discharge hole. , a plurality of vanes that are fitted into the rotor so as to be able to appear and retract in the radial direction of the rotor, and that slide into contact with the inner circumferential surface of the cam ring to divide the working chamber into a plurality of chambers;
It is equipped with a pressure sensor that detects the discharge hydraulic pressure of the hydraulic oil discharged from the working chamber through the discharge hole, and a solenoid valve that adjusts the predetermined supply hydraulic pressure based on the detection result of the pressure sensor and outputs the control hydraulic pressure. In a variable capacity vane pump that changes the amount of eccentricity of a cam ring according to an output control oil pressure, the predetermined supply oil pressure and discharge oil pressure are introduced and made to face each other via a piston, and the discharge oil pressure is adjusted according to the predetermined supply oil pressure. A variable capacity vane pump characterized by being provided with a relief valve that drains discharge hydraulic pressure by moving a piston when the relief pressure becomes higher than a set relief pressure. (2) The variable displacement vane pump according to claim 1, wherein the discharge hydraulic pressure is drained near the suction port of the suction hole by a relief valve. (3) A variable hydraulic pressure output means is provided which is connected to the relief valve and outputs a hydraulic pressure corresponding to the selected range of the automatic transmission of the vehicle as the supplied hydraulic pressure, so that the output hydraulic pressure in the forward range is higher than the output hydraulic pressure in the reverse range. to become smaller,
3. The variable displacement vane pump according to claim 1, wherein the variable hydraulic pressure output means outputs hydraulic pressure so that the relief pressure in the reverse range is higher than the relief pressure in the forward range.