JPH0348379B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a variable flow pump variable device, for example, a variable flow pump variable device that supplies hydraulic fluid to a hydraulic circuit of an automatic transmission of a vehicle.

(Prior art) As a variable device for a conventional variable flow pump, there are the following: Nissan Automatic Transacrylic (RN4FO2A type, RL4FO2A type) Maintenance Instruction Manual (February 1980, published by Nissan Motor Co., Ltd.) Nos. 29 and 30.
There is something written on the page. The variable device of this variable flow pump has a cam ring that can rotate around a rotational fulcrum at one end of the cam ring, and the discharge flow rate can be varied by rotating the cam ring and making it eccentric to the rotor. There is. The rotation of the cam ring is
It is controlled by the balance between springs provided opposite to each other at the other ends and the feedback hydraulic pressure from the pressure regulating valve. Feedback oil pressure is introduced through a pressure regulating valve, and when the oil flow rate required for the hydraulic circuit decreases and line pressure rises, the pressure regulating valve increases the feedback oil pressure.
By reducing the eccentricity of the cam ring, the discharge flow rate of the pump is reduced and the line pressure is restored to its original level.

However, in the case of such a variable device for a conventional variable flow pump, the pump discharge flow rate is uniformly determined based only on changes in line pressure due to changes in the oil flow rate required for the hydraulic circuit, regardless of the high or low temperature of the hydraulic oil. Because the structure was such that it changed to
When the temperature of the hydraulic oil becomes extremely low and the viscosity of the oil increases, the resistance in the oil passage increases, making it impossible to prevent delays in clutch engagement during startup or lever select engagement during gear changes, which can cause problems in the vehicle. There was a problem that the startability and drivability of the engine were affected.

(Purpose of the Invention) Therefore, the present invention improves the startability and drivability of a vehicle by preventing clutch engagement delays at startup and engagement delays after lever selection during gear shifting when the hydraulic oil temperature is extremely low. The purpose is to

(Structure of the Invention) A variable device for a variable flow rate pump according to the present invention is arranged such that the variable flow rate pump changes the discharge flow rate by rotating the cam ring, and the elastic means that abuts the rotating end of the cam ring are opposed to each other. It is equipped with a piston provided on a rod that abuts the rotating end of the cam ring, and an oil chamber that slidably accommodates the piston and introduces feedback hydraulic pressure that acts on the piston, and includes a plurality of sets of the piston and oil chamber. A valve is provided in series between the pressure regulating valve and at least one of the plurality of oil chambers so that when the viscosity of the hydraulic oil increases, feedback hydraulic pressure is introduced into the at least one oil chamber with respect to the other oil chambers. The structure is such that a pressure conversion element is provided to slow down the pressure.

(Operation of the invention) Since the viscosity of the oil is low in steady use conditions where the temperature of the hydraulic oil is relatively high, feedback oil pressure is smoothly introduced into all the multiple oil chambers, and when the feedback oil pressure becomes high, the piston is immediately moved. This allows the pump discharge flow rate to be quickly reduced. When the temperature of the hydraulic oil becomes extremely low and the viscosity of the oil increases, feedback oil pressure cannot be smoothly introduced into some of the multiple oil chambers, and even if the feedback oil chamber becomes high, the piston will not move immediately. Therefore, the pump discharge flow rate does not decrease rapidly, so the pump discharge flow rate remains at a high level at the beginning of the change in the feedback oil pressure. Therefore, the line pressure is maintained higher than when the hydraulic oil temperature is relatively high, and even if the viscosity of the hydraulic oil increases and the resistance in the oil passage increases, the large line pressure allows the oil to flow quickly. It is possible to prevent a delay in clutch engagement during startup, a delay in engagement after lever selection during gear shifting, etc.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is a diagram showing a variable flow rate pump variable device according to a first embodiment of the present invention.

In FIG. 1, 1 is a variable flow pump;
The discharge flow rate of the variable flow rate pump 1 can be reduced by pushing down a protrusion 2 fixed to the rotating end of a cam ring rotatably supported by a stationary member (not shown). A return spring (elastic means) 3 is interposed between the lower surface of the protrusion 2 in the figure and the stationary member, and when the return spring 3 is fully extended, the variable flow rate pump 1 has the highest discharge flow rate. in a state. One end of a piston rod 4 is in contact with the upper surface of the protrusion 2 in the figure, and two pistons 6 and 7 having different diameters are fixed in series to the other end of the piston rod 4. There is. The first piston 6 and the second piston 7 are slidably housed in a stepped cylinder 8 fixed to a stationary member.
A first oil chamber 10 is provided above the first piston 6 in the stepped cylinder 8 in the figure, and a second oil chamber 11 is provided between the first piston 6 and the second piston 7 in the stepped cylinder 8. is defined. The first piston 6 and the first
An oil-tight seal 14 is interposed between the oil chamber 10 and the sliding surface 10a. Since the diameter of the second piston 7 is larger than that of the first piston 6, the hydraulic area of the second piston 7 affected by the second oil chamber 11 is larger than the area of hydraulic action of the first piston 6 caused by the first oil chamber 10. The first oil chamber 10 of the stepped cylinder 8 communicates with the pressure regulating valve 12 via an oil passage 13, and the second
The oil chamber 11 also communicates with the pressure regulating valve 12 via an oil passage 15, and feeds back hydraulic pressure from the pressure regulating valve 12 to the first oil chamber 10 and the second oil chamber 11 through oil passages 13 and 15. It is now ready for implementation. A choke-type throttle valve (flow path resistance element) 16 is provided in the oil passage 13 near the first oil chamber 10 . This choke-type throttle valve 16 allows the introduction of feedback hydraulic pressure into the first oil sac 10 (at least one of the plurality of oil sacs) to the second oil sac 11 (another oil sac) when the viscosity of the hydraulic oil increases. It is a pressure conversion element that slows down the pressure. Projection 2, return spring 3, piston rod 4, first piston 6, second
Piton 7, stepped cylinder 8, first oil chamber 10, second
The oil chamber 11, the pressure regulating valve 12, the oil passages 13 and 15, the seal 14, and the choke valve 16 constitute a variable device 25 of the variable flow rate pump 1. The pressure regulating valve 12 is connected to an oil passage 17 through which oil discharged from the variable flow pump 1 passes through oil passages 18 and 20, and the oil discharged from the variable flow pump 1 is supplied to a hydraulic circuit (not shown). Oil pressure (line pressure)
It has the function of regulating pressure.

Next, the effect will be explained. When the oil flow rate required for the hydraulic circuit decreases and the line pressure increases, the pressure regulating valve 12 increases the feedback oil pressure sent to the stepped cylinder 8 and sends it to the first oil chamber 1 via oil passages 13 and 15.
0, high feedback oil pressure is introduced into the second oil chamber 11. At this time, the hydraulic pressure in the first oil chamber 10 and the second oil chamber 11 acts on the first piston 6 and the second piston 7, causing the first piston 6 and the second piston 7 to move downward in the figure, and the piston rod 4 to protrude. Rotating the cam ring of the variable flow pump 1 via the section 2,
By reducing the discharge flow rate of the variable flow rate pump 1, the line pressure is returned to an appropriate original value. in this case,
In a steady state of use where the temperature of the hydraulic oil is relatively high, the viscosity of the oil is low, so feedback oil pressure is smoothly introduced into the first oil chamber 10 and the second oil chamber 11, and the first piston 6 and the second piston 7 is immediately moved to quickly reduce the discharge flow rate of the variable flow rate pump 1. However, when the temperature of the hydraulic oil becomes extremely low and the viscosity of the oil increases, the oil passage 13
The oil is subjected to flow path resistance by the choke-type throttle valve 16, and the feedback hydraulic pressure is not smoothly introduced into the first oil chamber 10. As a result, the oil pressure in the first oil chamber 10 becomes a negative pressure. For this reason, the first piston 6 and the second piston 7 are driven only by the feedback hydraulic pressure introduced into the second oil chamber 11, and therefore cannot sufficiently overcome the pressing force of the return spring 3 on the opposite side of the protrusion 2. Since the first piston 6 and the second piston 7 do not move immediately and the discharge flow rate of the variable flow pump 1 does not decrease rapidly, the discharge flow rate of the variable flow pump 1 remains high at the beginning of the change in the feedback oil pressure. As a result, the line pressure is maintained higher than when the hydraulic oil temperature is relatively high, and even if the viscosity of the hydraulic oil increases and the resistance in the oil passage increases, the large line pressure allows the oil to flow quickly. , it is possible to prevent delays in clutch engagement during startup and engagement delays after lever selection during gear shifting. The line pressure, which was initially high as described above, is caused by the pistons 6 and 7 stroking very slowly for a sufficient period of time, during which time the oil temperature also rises and the discharge flow rate of the variable flow pump 1 decreases. Then, the line pressure shifts to the normal operating state.

FIG. 2 is a diagram showing a second embodiment. Said first
In the embodiment, an oil passage 13 was connected to the first oil chamber 10, whereas in this second embodiment, such an oil passage 13 is not provided, and instead, the first oil chamber 10 is connected to the oil passage 13.
and the second oil chamber 11 are formed between the first piston 6 and the sliding surface 10a of the first oil chamber 10.
It is connected by In other words, this interval 21
is formed between the sliding surfaces of one of the two sets of piston and oil chamber as a pressure conversion element (flow path resistance element) of the present invention. Projection 2, return spring 3, piston rod 4, first piston 6, second piston 7, stepped cylinder 8, first oil chamber 10,
The second oil chamber 11, the pressure regulating valve 12, the oil passage 15, and the gap 21 are connected to the variable device 35 of the variable flow rate pump 1.
Configure. In this second embodiment, the feedback hydraulic pressure introduced from the oil passage 15 to the second oil chamber 11 is introduced into the first oil chamber 10 through the gap 21, so that the temperature of the hydraulic oil is increased. When the hydraulic pressure is relatively high, the feedback hydraulic pressure is smoothly introduced into the first oil chamber 10, but when the hydraulic oil temperature becomes extremely low and the viscosity of the oil increases, it is subjected to flow path resistance due to the gap 21, and the feedback hydraulic pressure is reduced. The introduction into the first oil chamber 10 is delayed. Therefore, the first piston 6 and the second piston 7 do not move immediately and the discharge flow rate of the variable flow pump 1 does not decrease rapidly, so the discharge flow rate of the variable flow pump 1 remains high at the beginning of the change in the feedback oil pressure. Become. According to the second embodiment, the oil passage 13, seal 14, and choke-type throttle valve 16 as in the first embodiment are not required, and the overall structure of the device is simplified, the number of parts is reduced, and costs are reduced. can.

FIG. 3 is a diagram showing a third embodiment. Said second
In the embodiment, the first oil chamber 10 and the second oil chamber 11 were communicated through the gap 21, whereas in the third embodiment, the first piston 6 and the sliding surface 10a of the first oil chamber 10 communicated with each other through the gap 21. As in the first embodiment, a seal 14 is interposed between the first piston 6 and the first piston 6. resistance element)
The first oil chamber 10 and the second oil chamber 11 are communicated with each other. Projection 2, return spring 3, piston rod 4, first piston 6, throttle hole 6a, second
The piston 7, stepped cylinder 8, first oil chamber 10, second oil chamber 11, pressure regulating valve 12, seal 14, and oil passage 15 are part of the variable device 45 of the variable flow pump 1.
Configure. In this third embodiment, the feedback hydraulic pressure introduced from the oil passage 15 to the second oil chamber 11 is introduced into the first oil chamber 10 through the throttle hole 6a, and the hydraulic oil temperature is When the hydraulic pressure is relatively high, the feedback hydraulic pressure is smoothly introduced into the first oil chamber 10, but when the temperature of the hydraulic oil becomes extremely low and the viscosity of the oil increases, the pressure in the throttle hole 6a increases.
As a result, introduction of the feedback hydraulic pressure into the first oil chamber 10 is delayed. For this reason, the first
Since the piston 6 and the second piston 7 do not move immediately and the discharge flow rate of the variable flow pump 1 does not decrease rapidly, the discharge flow rate of the variable flow pump 1 remains high at the beginning of the change in the feedback oil pressure. According to this third embodiment, compared to the first embodiment, the oil passage 13 and the choke-type throttle valve 16 are not required.
The structure of the entire device can be simplified, the number of parts can be reduced, and costs can be reduced, and the first piston 6 is located in the first oil chamber 10 compared to the second embodiment.
The sliding surface 1 moves irregularly between the sliding surface 10a of the
It is possible to prevent Oa from being worn out or galled.

In addition, in the above embodiment, two pistons and two oil chambers each were used, but a larger number (three or more) of each may be used, in which case,
The above-mentioned pressure conversion element may be provided between the pressure regulating valve 12 and at least one oil chamber among the plurality of oil chambers. Furthermore, in the embodiment described above, when the oil temperature is low, the feedback oil pressure in the first oil chamber is set to be lower than the feedback oil pressure in the second oil chamber, but the feedback pressure may be reversed. In connection with this, in the embodiment described above, the first
Although the piston is provided above the second piston having a larger diameter in the drawing, this may also be reversed. Further, in the above embodiments, a flow path resistance element is used as a pressure conversion element, but other means of elements may be used as long as they can easily convert pressure. Furthermore, in the above embodiment, a chiyoke type throttle valve was used; however,
Orifice type throttle valves or other throttle valves may also be used.

(Effects of the Invention) As explained above, according to the present invention, a plurality of pistons are provided in series in a rod that variably operates the discharge flow rate of a variable flow rate pump, and at least one of the plurality of oil chambers housing these pistons is A pressure conversion element is provided between the oil chamber and the pressure regulating valve to slow the introduction of feedback hydraulic pressure into the at least one oil chamber relative to other oil chambers when the viscosity of the hydraulic oil increases, and the rod is moved. is slowed down when the viscosity of the hydraulic oil increases, so even when the temperature of the hydraulic oil is extremely low, it prevents a delay in clutch engagement at startup and a delay in engagement after lever selection during gear shifting, and improves vehicle performance. Startability and drivability can be improved. Furthermore, in the second embodiment, the structure of the entire device can be simplified, the number of parts can be reduced, and costs can be reduced. Further, in the third embodiment, the structure of the entire device can be simplified, the number of parts can be reduced, and costs can be reduced, and wear and galling during sliding of the piston can also be prevented. In addition, by actively reducing the aperture area, it can also function as a damper for countermeasures against hydraulic vibration. Furthermore, when there is a delay in engine response, such as in a turbo engine, by reducing the cross-sectional area of the throttle to allow more movement of the piston, it is possible to generate line pressure that matches the engine torque response.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a variable device for a variable flow pump according to a first embodiment of the present invention, FIG. 2 is an overall configuration diagram of a variable device for a variable flow pump according to a second embodiment, and FIG. FIG. 7 is an overall configuration diagram of a variable device of a variable flow rate pump according to a third embodiment. DESCRIPTION OF SYMBOLS 1... Variable flow rate pump, 2... Projection part (rotating end of cam ring), 3... Return spring (elastic means), 4... Piston rod, 6... First
Piston, 6a... Throttle hole (pressure conversion element, flow path resistance element), 7... Second piston, 10... First
Oil chamber, 10a...Oil chamber sliding surface, 11...Second oil chamber, 12...Pressure regulating valve, 16...Cyoke type throttle valve (pressure conversion element, flow path resistance element), 21...
Gap (pressure conversion element, flow path resistance element), 25, 3
5, 45... Variable flow rate pump variable device.

Claims (1)

[Scope of Claims] 1. In a variable flow pump that changes the discharge flow rate by rotating the cam ring, an elastic means that contacts the rotating end of the cam ring and a rod that contacts the rotating end of the cam ring so as to face each other. In a variable flow rate pump variable device comprising a piston and an oil chamber that slidably accommodates the piston and introduces feedback oil pressure from a pressure regulating valve that causes the piston to act as a piston, the piston and the oil chamber are A plurality of sets are provided in series, and between the pressure regulating valve and at least one of the plurality of oil chambers,
1. A variable device for a variable flow rate pump, characterized in that a pressure conversion element is provided that slows down the introduction of feedback hydraulic pressure into the at least one oil chamber relative to other oil chambers when the viscosity of hydraulic oil increases. 2. The variable flow pump variable device according to claim 1, wherein the plurality of sets of pistons and oil chambers include two pistons and two oil chambers that house both pistons. 3. The pressure conversion element according to claim 2, wherein the pressure conversion element is a flow resistance element provided in an oil passage that introduces hydraulic pressure into one of the two oil chambers. Variable device for variable flow pump. 4. The variable flow rate pump variable device according to claim 3, wherein the flow path resistance element is a throttle valve provided in the oil path. 5. The two pistons housed in the two oil chambers have different hydraulic action areas,
Claims characterized in that the flow path resistance element is a gap formed between a sliding surface of one of the two pistons and the oil chamber so as to communicate the two oil chambers. 4. The variable flow rate pump variable device according to item 3. 6. The two pistons housed in the two oil chambers have different hydraulic action areas,
Claim 3, wherein the flow path resistance element is a throttle hole formed in a piston housed in one of the two oil chambers and communicating the two oil chambers. Variable device for variable flow pump.