CN216742546U - Displacement pump type retarder - Google Patents

Abstract

The application relates to vehicle auxiliary braking, in particular to a displacement pump type retarder. The volume pump type retarder comprises a liquid storage tank, a volume pump type retarding mechanism, a control pump and an unloading valve; a working cavity is formed in the displacement pump type retarding mechanism, a working part is arranged in the working cavity, and the working cavity is divided into a first area and a second area by the running area of the working part; the unloading valve can be connected between the first area and the second area in an on-off mode, the unloading valve is provided with a first control port, and the control pump is communicated between the liquid storage tank and the first control port; when the pressure of the first control port is reduced to a first pressure threshold value, the unloading valve is switched to a state of communicating the first zone with the second zone. The volume pump type retarder can enable the no-load resistance of the volume pump type retarding mechanism, and further reduce energy loss.

Description

Displacement pump type retarder

Technical Field

The application relates to vehicle auxiliary braking, in particular to a displacement pump type retarder.

Background

The retarder is used as an auxiliary braking component of the vehicle, reduces the load of the braking system of the original vehicle by acting on the transmission system of the original vehicle, enables the vehicle to decelerate uniformly, improves the reliability of the braking system of the vehicle, prolongs the service life of the braking system, and is an important component for ensuring the safety performance of the vehicle, particularly ensuring the safe running of the vehicle in a certain speed range.

When braking is completed and the speed range of the automobile meets the requirement, the retarder usually idles and continues to perform auxiliary braking, so that energy loss is caused, and the running economy of the retarder and the whole automobile is reduced.

SUMMERY OF THE UTILITY MODEL

The application aims to provide a displacement pump type retarder, which solves the technical problem that the energy loss is caused by the fact that the retarder in the prior art is continuously braked in an idle load state to a certain extent.

The application provides a displacement pump type retarder which comprises a liquid storage tank, a displacement pump type retarder mechanism, a control pump and an unloading valve;

a working cavity is formed in the displacement pump type retarding mechanism, a working part is arranged in the working cavity, and the working cavity is divided into a first area and a second area by the running area of the working part;

the unloading valve can be connected between the first area and the second area in an on-off mode, the unloading valve is provided with a first control port, and the control pump is communicated between the liquid storage tank and the first control port;

when the pressure of the first control port is reduced to a first pressure threshold, the unloading valve is switched to a state of communicating the first zone with the second zone.

In any one of the above technical solutions, further, the volume pump retarder further includes a liquid inlet check valve, the volume pump retarder has a liquid inlet communicated with the first region, the liquid inlet check valve is connected between the liquid inlet and the liquid storage tank in a break-make manner, and the liquid inlet check valve only allows liquid media to flow unidirectionally from the liquid storage tank to the liquid inlet in an open state.

In any of the above technical solutions, further, the liquid inlet check valve has a second control port, and the second control port is communicated with the control pump;

when the pressure of the second control port is reduced to a second pressure threshold value, the liquid inlet one-way valve is switched to a state that the liquid inlet is cut off from the liquid storage tank.

In any of the above technical solutions, further, the control pump is a single-acting vane pump.

In any of the above technical solutions, further, the displacement pump type retarder further includes a liquid injection pipeline, and the control pump is communicated with the first area through the liquid injection pipeline;

and a liquid spraying hole is formed at the communication position of the liquid spraying pipeline and the first area, and the spraying direction of the liquid spraying hole faces the first area.

In any of the above technical solutions, further, the number of the liquid ejecting holes is one or more.

In any of the above technical solutions, further, the displacement pump type retarder further includes a liquid return pipeline, the displacement pump type retarder is provided with a liquid discharge port communicated with the first area, and the liquid return pipeline is communicated between the liquid storage tank and the liquid discharge port.

In any of the above technical solutions, further, the positive displacement pump retarder further includes an intake valve, and the intake valve is connected to the first area in a switchable manner to control switching between the first area and the atmosphere.

In any of the above solutions, further, the first pressure threshold is greater than the second pressure threshold;

the pumping pressure range of the control pump includes a first pumping pressure that is less than the second pressure threshold.

In any of the above solutions, further, the pumping pressure range of the control pump includes a second pumping pressure, and the second pumping pressure is greater than the first pressure threshold.

Compared with the prior art, the beneficial effects of this application do:

the application provides a displacement pump formula retarber includes liquid reserve tank, displacement pump formula retarding mechanism, control pump and unloading valve. After the loading is finished, the pumping pressure of the control pump is regulated to be lower than a first pressure threshold value, so that the pressure of a first control port of the unloading valve is reduced to be lower than the first pressure threshold value, the unloading valve is switched to a state of communicating a first area and a second area of the displacement pump type speed reducing mechanism, the pressure difference between the first area and the second area is eliminated, the pressure cannot be built in a working cavity, namely, the no-load resistance of the displacement pump type speed reducing mechanism is obviously reduced, the purpose of reducing energy loss is further achieved, the power utilization efficiency of a transmission system for carrying out auxiliary braking through the displacement pump type speed reducing mechanism is improved, and the displacement pump type speed reducing mechanism is simple in structure, accurate and efficient to control, and is favorable for carrying out pressure relief operation on the displacement pump type speed reducing mechanism timely and reliably.

Drawings

In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic diagram of a first state of a positive displacement pump retarder provided in an embodiment of the present application;

fig. 2 is a schematic diagram of a second state of the positive displacement pump retarder provided in the embodiment of the present application;

FIG. 3 is a schematic diagram of a third state of the positive displacement pump retarder according to the embodiment of the present disclosure;

fig. 4 is a partial schematic view of a volumetric pump retarder provided in an embodiment of the present application.

Reference numerals:

1-a positive displacement pump retarder; 10-a positive displacement pump type retarding mechanism; 100-liquid inlet; 101-an air inlet; 102-a drain port; 106-first zone; 107-second zone; 11-oil supply line; 12-a liquid return line; 13-liquid spraying pipeline; 14-an intake valve; 15-an unloading valve; 17-controlling the pump; 170-flow regulating valve; 171-single-acting leaf; 18-a first safety valve; 19-a first filter cartridge; 20-a second filter element; 21-a second safety valve; 22-a third safety valve; 23-a heat exchanger; 24-a first pressure detecting member; 25-a second pressure detecting means; 26-temperature detection means; 27-a liquid storage tank; 28-liquid inlet one-way valve; 29-flow limiting valve.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

Example one

Referring to fig. 1 to 4, an embodiment of the present application provides a control method of a displacement pump retarder for controlling, particularly, unloading, the displacement pump retarder 10.

The displacement pump type retarding mechanism 10 is made by adopting the displacement pump principle, so that the liquid medium is sucked and discharged by utilizing the periodic change of the working volume, and in the process of sucking and discharging the liquid medium, the working cavity establishes pressure difference to consume the kinetic energy of a transmission system of a vehicle so as to achieve the aim of auxiliary braking. For example, a reciprocating pump retarder, a mixed flow pump retarder or a rotor pump retarder may be included.

Specifically, the displacement pump type retarder mechanism 10 includes a retarder cylinder, a working chamber formed inside the retarder cylinder, and a working member disposed in the working chamber, wherein an operating region of the working member divides the working chamber into a first region 106 and a second region 107, and the retarder cylinder is formed with a liquid inlet 100 and a liquid outlet 102, so that a liquid medium flows into the first region 106 through the liquid inlet 100, can flow into the second region 107 under the action of the working member, and is discharged from the second region 107 through the liquid outlet 102.

In an alternative of this embodiment, the control method of the displacement pump type speed reducing mechanism includes the steps of:

step S300, determining that the displacement pump type retarding mechanism 10 needs to be unloaded;

in step S310, the first block 106 and the second block 107 of the displacement pump type speed reducing mechanism 10 are switched from the disconnected state to the connected state.

In step S300, after the traveling system of the vehicle has returned to normal traveling in general, the braking action needs to be canceled, and therefore the relief of the displacement pump retarder 10 is required.

In step S310, the state in which the displacement pump type speed reducing mechanism 10 performs the assist braking is defined as the loaded state, and in the loaded state, the first zone 106 and the second zone 107 of the displacement pump type speed reducing mechanism 10 are in the state of being separated from each other in the region other than the working chamber, so that a pressure difference exists between the first zone 106 and the second zone 107, and the pressure can be built up in the working chamber.

When the displacement pump type speed reducing mechanism 10 needs to be unloaded, the first area 106 and the second area 107 of the displacement pump type speed reducing mechanism 10 are communicated at positions outside the working chamber, so that the first area 106 and the second area 107 are switched to be communicated at positions outside the working chamber, and oil liquid in the second area 107 can flow to the first area 106 until the pressure difference between the first area 106 and the second area 107 is eliminated, so that the pressure in the working chamber cannot be built, namely, the unloading is realized.

In an alternative of this embodiment, the control method of the displacement pump type speed reducing mechanism includes the steps of:

step S400, determining that the displacement pump type retarding mechanism needs to be unloaded;

step S410, switching the first region 106 of the displacement pump type speed reducing mechanism 10 from a state of being communicated with the liquid medium source to a state of being disconnected;

step S420, switching the first zone 106 and the second zone 107 of the displacement pump type speed reducing mechanism 10 from a disconnected state to a connected state;

in step S410, in the loaded state, the first region 106 of the positive displacement pumping retarder mechanism 10 is in communication with a source of liquid medium, such that the positive displacement pumping retarder mechanism 10 draws liquid medium from the source of liquid medium, providing a basis for the operation of the positive displacement pumping retarder mechanism 10.

In order to keep the pressure balance between the first land 106 and the second land 107 in the unloaded state by continuously supplying the liquid medium to the displacement pump type speed reducing mechanism 10, it is necessary to cut off the communication between the first land 106 of the displacement pump type speed reducing mechanism 10 and the liquid medium source, and to ensure the stability of the unloaded state.

It is to be emphasized that the status switching operation in step S410 is not later than the status switching operation in step S420, and alternatively, the two status switching operations mentioned in step S410 and step S420 may be performed synchronously.

The control method of the displacement pump type retarding mechanism comprises the following steps:

step S500, determining that the displacement pump type retarding mechanism needs to be unloaded;

step S510, switching the first area 106 and the second area 107 of the displacement pump type speed reducing mechanism 10 from a disconnected state to a connected state, and switching the first area 106 and the liquid medium source of the displacement pump type speed reducing mechanism 10 from a connected state to a disconnected state;

in step S520, the liquid inlet of the displacement pump type speed reducing mechanism 10 is connected to the atmosphere, and the first region 106 of the displacement pump type speed reducing mechanism 10 is replenished with the liquid medium in a dot-like liquid spraying manner.

In step S520, if the liquid medium stays in the working chamber for a long time in the unloaded state, the temperature of the liquid medium in the working chamber rises due to the effect of the long-term idling of the displacement pump type speed reducing mechanism 10, and therefore, it is necessary to discharge the liquid medium in time and continuously lubricate the internal structure of the displacement pump type speed reducing mechanism 10 to prevent the occurrence of high temperature failure.

Therefore, the first region 106 of the displacement pump type speed reducing mechanism 10 is communicated with the atmosphere, so that the displacement pump type speed reducing mechanism 10 can be evacuated, and the oil in the working chamber can be discharged.

Further, the first region 106 of the displacement pump type retarder 10 is replenished with the liquid medium in the form of a dot-like spray, so that when the replenished oil reaches a certain amount, the liquid medium in the working chamber can be discharged out of the displacement pump type retarder 10, and circulates between the communication passage between the first region 106 and the second region 107 and the working chamber, so as to achieve the effect of continuously lubricating the displacement pump type retarder 10.

Example two

Referring to fig. 1 to 4, an embodiment of the present application provides a volumetric pump retarder 1, including a liquid storage tank 27, a volumetric pump retarder 10, a control pump 17, an unloading valve 15, and a liquid inlet check valve 28. In fig. 1 to 3, a circulation path of the liquid medium is shown by a thick solid line.

Hereinafter, the above-described components of the displacement pump type speed bump mechanism 10 will be described in detail.

In an alternative embodiment, the principle of the displacement pump retarder mechanism 10 operating on the displacement pump principle has been described in detail above, and therefore will not be described in detail here.

In this embodiment, as shown in fig. 1, the volumetric pump retarder 1 further includes an oil supply line 11 and a liquid return line 12 communicated with the reservoir 27. One end of the oil supply pipeline 11 is communicated with the liquid storage tank 27, the other end of the oil supply pipeline 11 is communicated with the liquid inlet 100 of the displacement pump type retarding mechanism 10, one end of the liquid return pipeline 12 is communicated with the liquid storage tank 27, and the other end of the liquid return pipeline 12 is communicated with the liquid outlet 102 of the displacement pump type retarding mechanism 10, so that the displacement pump type retarder 1 can absorb oil from the liquid storage tank 27 through the oil supply pipeline 11 and return oil to the liquid storage tank 27 through the liquid return pipeline 12 in the loading process to form circulation.

In this embodiment, the return line 12 is provided with a flow restriction valve 29 in order to facilitate the working chamber of the displacement pump retarder 10 to build up a stable pressure in the loaded state.

In the present embodiment, in order to facilitate understanding of the pressure and temperature of the liquid medium in the liquid return line 12, the first pressure detecting member 24 and the first temperature detecting member 26 are provided in a portion of the liquid return line 12 between the restrictor valve 29 and the liquid discharge port 102.

In this embodiment, the liquid return line 12 is provided with a heat exchanger 23 at a position downstream of the flow restriction valve 29 in order to lower the temperature of the liquid medium flowing back to the reservoir 27 to ensure that the liquid medium is not excessively heated when it is sucked away again. Further, to avoid flooding the heat exchanger 23, the heat exchanger 23 is connected in parallel with a third relief valve 22.

Optionally, the heat exchanger 23 is a plate heat exchanger.

In this embodiment, in order to prevent impurities from being mixed in the liquid medium flowing back into the heat exchanger 23 and to protect the cleanliness of the environment in the heat exchanger 23 and the liquid storage tank 27, the liquid return line 12 is provided with a first filter element 19 at a position between the heat exchanger 23 and the flow restriction valve 29. Further, in order to avoid flooding the first filter element 19, the first filter element 19 is connected in parallel with a second relief valve 21. Further, in order to prevent impurities from being mixed in the liquid medium flowing back into the liquid storage tank 27 and to protect the cleanliness of the environment in the liquid storage tank 27, the liquid return line 12 is provided with a second filter element 20 at a position between the heat exchanger 23 and the liquid storage tank 27.

In this embodiment, in order to avoid overflow at the control pump 17, the control pump 17 is connected in parallel with the first safety valve 18, and in order to facilitate understanding of the pressure of the control pump 17, a second pressure detecting member 25 is disposed between the first safety valve 18 and the liquid inlet 100.

In an alternative of this embodiment, after the loading state is finished, the vehicle starts to run normally, and if the displacement pump type retarder 10 does not stop pumping oil, the braking force is continuously applied to the drive shaft of the running system, which provides resistance to the normal running of the running system, resulting in energy loss.

Therefore, in order to reduce the energy loss during the normal running of the vehicle, the unloading valve 15 is connected between the first and second ranges 106 and 107 of the displacement pump type speed reducing mechanism 10 in an on-off manner, that is, the unloading valve 15 has two states, namely, a first state in which the unloading valve 15 can directly connect the first and second ranges 106 and 107 and a second state in which the unloading valve 15 can block the first and second ranges 106 and 107.

The unloading valve 15 has a first control port, the state switching of the unloading valve 15 is determined by the pressure of the first control port, and the control pump 17 is communicated between the first control port and the reservoir 27, so that the pressure of the first control port of the unloading valve 15 is controlled by the control pump 17, and further the state switching of the unloading valve 15 is determined by the pumping pressure of the control pump 17.

When the control pump 17 is in the pumping state and the pumping pressure of the control pump 17 is kept above the first predetermined pressure, the pressure of the first control port of the unloading valve 15 is also kept above the first predetermined pressure under the action of the control pump 17, so that the unloading valve 15 is switched to and kept in the second state, the first zone 106 and the second zone 107 are cut off, a pressure difference is formed between the first zone 106 and the second zone 107, the pumping condition is met, the pressure in the working chamber can be established, and the displacement pump type speed reducing mechanism 10 is kept in the loading state.

When the pumping pressure of the control pump 17 is reduced below a first predetermined pressure or even in a closed state, the first control port pressure of the unloading valve 15 is reduced below the first predetermined pressure under the action of the control pump 17, so that the unloading valve 15 is switched to and maintained in the first state, the liquid inlet 100 is communicated with the liquid outlet 102, the first zone 106 is communicated with the second zone 107, a pressure difference cannot be formed between the first zone 106 and the second zone 107, pressure cannot be built in the working chamber, and the displacement pump type speed reducing mechanism 10 is switched to the unloading state.

That is, the control pump 17 and the unloading valve 15 cooperate with each other, so that the displacement pump type speed reducing mechanism 10 can be automatically unloaded after the loading is finished, thereby achieving the purpose of energy saving.

Optionally, the unloading valve 15 is an overflow valve, and the first pressure threshold is a set pressure of the overflow valve.

It should be emphasized that one or more sets of the first section 106 and the second section 107 may be formed in the working chamber, instead of being limited to only one set of the first section 106 and the second section 107, and in the case that multiple sets of the first section 106 and the second section 107 are formed in the working chamber, each set of the first section 106 and the second section 107 is separately controlled to be unloaded by one unloading valve 15, or each set of the first section 106 and the second section 107 shares one unloading valve 15 to be controlled to be unloaded.

The unloading valve 15 is directly installed between the first zone 106 and the second zone 107, instead of directly installed between the liquid inlet 100 and the liquid outlet 102, so that the unloading path can be effectively shortened, the unloading reaction speed can be increased, and the loss can be reduced.

It will be appreciated that, for other reasons, it is also possible to employ an unloader valve directly between the inlet port 100 and the outlet port 102, thereby indirectly controlling the on-off relationship between the first zone 106 and the second zone 107 by controlling the on-off relationship between the inlet port 100 and the outlet port 102.

In the alternative of this embodiment, the volumetric pump retarder 1 further includes a liquid inlet check valve 28, the liquid inlet check valve 28 can be connected between the liquid inlet 100 and the liquid storage tank 27 in an on-off manner, that is, the liquid inlet check valve 28 has two states, the two states are respectively a third state and a fourth state, in the third state, the liquid inlet check valve 28 is opened, the liquid inlet 100 is communicated with the liquid storage tank 27, and only the liquid medium is allowed to flow from the liquid storage tank 27 to the liquid inlet 100 in a one-way manner, in the fourth state, the liquid inlet check valve 28 is closed, and the liquid inlet 100 is cut off from the liquid storage tank 27.

Specifically, the liquid inlet check valve 28 is provided in the oil supply line 11, and the on/off of the oil supply line 11 is controlled by switching the state of the liquid inlet check valve 28. Thereby switching the inlet check valve 28 to the third state when the positive displacement pump retarder mechanism 10 needs to be in the loaded state.

When the positive displacement pump type speed reducing mechanism 10 is in the unloading state, the liquid inlet check valve 28 is switched to the fourth state, so that the liquid medium in the liquid storage tank 27 can be prevented from flowing back to the working cavity through the liquid inlet 100 under the action of gravity, circulation caused by the liquid medium flowing back to the first region 106 can be avoided when the unloading valve 15 is opened, and accordingly resistance caused by the circulation can be avoided accidentally, and the stability of the unloading state can be ensured by switching the liquid inlet check valve 28 to the fourth state no later than when the unloading valve 15 is switched to the first state.

In this embodiment, in order to facilitate switching the state of the liquid inlet check valve 28, the liquid inlet check valve 28 has a second control port, the state switching of the liquid inlet check valve 28 is determined by the second control port, and when the pressure of the second control port is reduced to a second pressure threshold, the liquid inlet check valve 28 is switched to a fourth state, that is, the liquid inlet 100 is disconnected from the liquid storage tank 27. The second control port is communicated with the control pump 17, the pressure of the second control port is determined by the pumping pressure of the control pump 17, that is, the state switching of the liquid inlet check valve 28 is determined by the pumping pressure of the control pump 17, and when the pumping pressure of the control pump 17 is reduced to a second pressure threshold value, the liquid inlet check valve 28 cuts off the liquid inlet 100 from the liquid storage tank 27.

In an alternative of this embodiment, after the unloading state continues for a period of time, because the liquid medium is retained in the working chamber, under the influence of the continuous idle rotation of the displacement pump type speed reducing mechanism 10, the temperature of the liquid medium in the working chamber rises, and if the liquid medium cannot be discharged in time or participate in circulation, the temperature in the working chamber is too high, and thus the problem of lubrication failure occurs.

The positive displacement pump retarder 1 further comprises a liquid injection line 13, and the liquid injection line 13 is communicated between the control pump 17 and the first area 106, so that the control pump 17 can supplement the liquid medium to the first area 106 through the liquid injection line 13.

The liquid spraying pipe 13 is connected to the liquid inlet 100 to form a liquid spraying hole, the liquid spraying hole is located between the first area 106 and the liquid inlet check valve 28, the spraying direction of the liquid spraying hole is toward the first area 106, so that in an unloading state, under the pumping action of the control pump 17, the liquid medium can be supplemented into the first area 106, and further under the pressure action of the supplemented liquid medium, the liquid medium in the working chamber circulates, specifically, when the total oil amount in the working chamber is small, as shown in fig. 2, a small circulation can be formed between the displacement pump type speed reducing mechanism 10 and the unloading valve 15, and when the total oil amount in the working chamber is large, as shown in fig. 3, on the basis of the small circulation, a large circulation can be formed between the liquid storage tank 27, the oil supply pipe 11, the air inlet pipe, the displacement pump type speed reducing mechanism 10 and the liquid return pipe 12.

Thereby on the one hand make liquid medium dispel the heat in the course of circulating, cool off through heat exchanger 23 even, on the other hand can also make liquid medium lubricate whole positive displacement pump retarder 1 in the course of circulating.

In this embodiment, the number of the liquid injection holes is one or more, for example, two or three, and the specific number may be determined by comprehensively considering the amount of injected oil and the diameter of the oil injection hole, so that on the premise of ensuring that the lubrication effect is achieved, it is avoided that the flow rate of the liquid medium is too large and the braking resistance generated in the process of circulating lubrication is too large, that is, the pump 17 is controlled to operate at a small pump amount.

In this embodiment, the positive displacement retarder 1 further comprises an air inlet valve 14, and the air inlet valve 14 is openably connected to the first zone 106 to control the opening and closing between the first zone 106 and the atmosphere.

Therefore, when the displacement pump type speed reducing mechanism 10 needs to be unloaded, the air inlet valve 14 is switched to the open state, and the first area 106 is communicated with the atmosphere, so that the displacement pump type speed reducing mechanism 10 generates a suction phenomenon in the rotating process, pressure cannot be built in the working cavity, and excessive braking resistance of the displacement pump type speed reducing mechanism 10 is avoided.

Conversely, in the loaded state, the inlet valve 14 is switched to the open state, the first zone 106 being sealed from the atmosphere, so that pressure can build up inside the working chamber.

Optionally, the intake valve 14 is a two-position two-way solenoid on-off valve.

Alternatively, the positive displacement retarder 1 is formed with an inlet port 101 communicating with the first zone 106, and the inlet valve 14 is mounted in the inlet port 101.

In this embodiment, the first pressure threshold is greater than the second pressure threshold, and the range of pumping pressures for controlling the pump 17 includes the second pumping pressure, which is greater than the first pressure threshold. Therefore, when the volume pump type speed reducing mechanism 10 needs to be loaded, the pumping pressure of the control pump 17 is adjusted to the second pumping pressure, the air inlet valve 14 is disconnected, the liquid inlet check valve 28 communicates the liquid inlet 100 with the liquid storage tank 27, the unloading valve 15 cuts off the first region 106 from the second region 107, so that the volume pump type speed reducing mechanism 10 can suck oil through the oil supply pipeline 11, pressure is built in the working cavity, and oil is returned to the liquid storage tank 27 through the liquid return pipeline 12, that is, the volume pump type speed reducing mechanism 10 starts to operate in a loaded state.

In this embodiment, the first pressure threshold is greater than the second pressure threshold, and the range of pumping pressures for controlling the pump 17 includes the first pumping pressure, which is less than the second pressure threshold. Therefore, when the displacement pump type speed reducing mechanism 10 needs to be unloaded, the pumping pressure of the control pump 17 is adjusted to the first pumping pressure, the air inlet valve 14 is opened, the liquid inlet check valve 28 cuts off the liquid inlet 100 from the liquid storage tank 27, the unloading valve 15 connects the first region 106 with the second region 107, and the control pump 17 starts to perform point-like liquid injection to the first region 106, so that a sufficient pressure difference cannot be established in the working chamber of the displacement pump type speed reducing mechanism 10, that is, the displacement pump type speed reducing mechanism 10 starts to operate in an unloading state and can be lubricated.

In an alternative of this embodiment, the control pump 17 is a variable displacement pump, in particular a single-acting vane pump. Specifically, the single-acting vane pump includes a single-acting vane 171 and a flow regulating valve 170, and the flow regulating valve 170 is connected between a control port and an outlet of the single-acting vane 171, so that the pumping flow rate and the pumping pressure of the single-acting vane pump can be adjusted.

The control pump 17 is set to be a single-acting vane pump, so that the output flow rate of the control pump is uniform compared with a gear pump, the operation is stable, the noise is low, the working pressure is high, the volume efficiency is high, the flow rate adjustment is easy to realize, the structure is compact, the outline size is small, and the flow rate is large.

It will be appreciated that other variable displacement pumps, such as an internal meshing gerotor or gear type, may be used as the control pump 17.

Alternatively, the liquid medium may be a high viscosity oil medium or a magnetorheological fluid medium.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention. Moreover, those skilled in the art will appreciate that although some embodiments described herein include some features included in other embodiments, not others, combinations of features of different embodiments are meant to be within the scope of the utility model and form different embodiments. For example, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the utility model and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Claims (10)

1. A kind of displacement pump type retarder, characterized by, including liquid reserve tank, displacement pump type retarding mechanism, control pump and relief valve;

a working cavity is formed in the displacement pump type retarding mechanism, a working part is arranged in the working cavity, and the working cavity is divided into a first area and a second area by the running area of the working part;

the unloading valve can be connected between the first area and the second area in an on-off mode, the unloading valve is provided with a first control port, and the control pump is communicated between the liquid storage tank and the first control port;

when the pressure of the first control port is reduced to a first pressure threshold value, the unloading valve is switched to a state that the first zone is communicated with the second zone.

2. The positive displacement pump type retarder of claim 1, further comprising a liquid inlet check valve, wherein the positive displacement pump type retarder is provided with a liquid inlet communicated with the first area, the liquid inlet check valve is connected between the liquid inlet and the liquid storage tank in a switching manner, and the liquid inlet check valve only allows the liquid medium to flow from the liquid storage tank to the liquid inlet in a one-way manner in an opening state.

3. A positive displacement pump retarder according to claim 2, wherein the inlet check valve has a second control port, the second control port being in communication with the control pump;

when the pressure of the second control port is reduced to a second pressure threshold value, the liquid inlet one-way valve is switched to a state that the liquid inlet is cut off from the liquid storage tank.

4. A positive-displacement retarder according to claim 3, characterised in that the control pump is a single-acting vane pump.

5. A positive-displacement pump retarder according to claim 3, further comprising a liquid injection line through which the control pump communicates with the first zone;

and a liquid spraying hole is formed at the communication position of the liquid spraying pipeline and the first area, and the spraying direction of the liquid spraying hole faces the first area.

6. A positive-displacement pump retarder according to claim 5, wherein the number of liquid injection holes is one or more.

7. The positive displacement pump retarder of claim 3, further comprising a liquid return pipeline, wherein the positive displacement pump retarder is provided with a liquid discharge port communicated with the first region, and the liquid return pipeline is communicated between the liquid storage tank and the liquid discharge port.

8. A positive-displacement retarder according to claim 3, further comprising an inlet valve, which is openably connected to the first zone to control the opening and closing between the first zone and the atmosphere.

9. A positive-displacement pump retarder according to claim 3, wherein the first pressure threshold is greater than the second pressure threshold;

the range of pumping pressures of the control pump includes a first pumping pressure that is less than the second pressure threshold.

10. The positive displacement pump retarder of claim 9, wherein the range of pumping pressures of the control pump includes a second pumping pressure, the second pumping pressure being greater than the first pressure threshold.

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