Combined control system of hydraulic cylinder and hydraulic motor

Abstract

The utility model provides a combined control system of a hydraulic cylinder and a hydraulic motor, which relates to the technical field of excavator hydraulic systems and comprises the hydraulic cylinder, a first oil way, a second oil way, a first overflow oil way, a first overflow valve, a second overflow oil way and a second overflow valve. One end of the first oil way communicates with a rod cavity of the hydraulic cylinder; one end of the second oil way is communicated with a rodless cavity of the hydraulic cylinder; one end of the first overflow oil way communicates with the first oil way, and the other end communicates with the second oil way; the first overflow valve is arranged on the first overflow oil way and used for enabling hydraulic oil in the rod cavity of the hydraulic cylinder to overflow from the first overflow oil way when the working pressure of the rod cavity of the hydraulic cylinder is too large. One end of the second overflow oil way is communicated with the second oil way; the second overflow valve is arranged on the second overflow oil way and used for enabling hydraulic oil in the rodless cavity of the hydraulic cylinder to overflow from the second overflow oil way when the working pressure of the rodless cavity of the hydraulic cylinder is too large. A hydraulic loop and hydraulic elements are simplified, the manufacturing cost and the failure rate are reduced, and maintenance is convenient.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic system technology for excavators, and in particular to a combined control system for a hydraulic cylinder and a hydraulic motor. Background Technology

[0002] Currently, excavators typically transmit power through a hydraulic system to control the head changer and perform various actions. The excavator hydraulic system is a combination of various hydraulic components organically connected by pipelines according to the transmission requirements of the head changer and other mechanisms.

[0003] Hydraulic cylinders and hydraulic motors are the actuators of an excavator's hydraulic system. Their function is to convert the pressure energy of the hydraulic oil within the system into mechanical energy, driving the excavator head changer to perform various actions such as linear reciprocating motion or rotary motion. However, because the working pressure of the hydraulic cylinder is much lower than that of the hydraulic motor, separate hydraulic circuits or multi-stage overflow circuits are usually required to control the working pressure of the hydraulic cylinder and hydraulic motor individually. This results in a complex and chaotic hydraulic circuit and components within the narrow space of the excavator head changer, leading to an extremely high failure rate, difficult maintenance, and high manufacturing costs. Utility Model Content

[0004] The purpose of this utility model is to provide a combined control system for a hydraulic cylinder and a hydraulic motor to solve at least one of the aforementioned technical problems in the prior art.

[0005] To solve the above-mentioned technical problems, this utility model provides a combined control system for a hydraulic cylinder and a hydraulic motor, comprising: a hydraulic cylinder, a first oil circuit, a second oil circuit, a first overflow oil circuit, a first overflow valve, a second overflow oil circuit, and a second overflow valve;

[0006] One end of the first oil circuit is connected to the rod chamber of the hydraulic cylinder, and is used to supply oil to the rod chamber of the hydraulic cylinder or to discharge hydraulic oil from the rod chamber of the hydraulic cylinder;

[0007] One end of the second oil circuit is connected to the rodless chamber of the hydraulic cylinder, and is used for discharging hydraulic oil from the rodless chamber of the hydraulic cylinder or supplying oil to the rodless chamber of the hydraulic cylinder;

[0008] One end of the first overflow oil circuit is connected to the first oil circuit, and the other end is connected to the second oil circuit;

[0009] The first overflow valve is installed in the first overflow oil circuit and is used to overflow the hydraulic oil in the rod chamber of the hydraulic cylinder from the first overflow oil circuit when the working pressure of the rod chamber of the hydraulic cylinder is too high, thereby controlling the working pressure of the hydraulic cylinder when oil is supplied from the first oil circuit to the rod chamber of the hydraulic cylinder and maintaining the working pressure of the hydraulic cylinder stable.

[0010] One end of the second overflow oil circuit is connected to the second oil circuit;

[0011] The second overflow valve is installed in the second overflow oil circuit and is used to allow the hydraulic oil in the rodless chamber of the hydraulic cylinder to overflow from the second overflow oil circuit when the working pressure of the rodless chamber of the hydraulic cylinder is too high. This controls the working pressure of the hydraulic cylinder when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder, and maintains the working pressure of the hydraulic cylinder stable.

[0012] This application simplifies the hydraulic circuit and hydraulic components within the narrow space of the excavator head changing device by setting up a first overflow oil circuit and a second overflow oil circuit, respectively, and controls the working pressure of the hydraulic cylinder when supplying oil to the rod chamber and rodless chamber of the hydraulic cylinder, thereby reducing the cost and failure rate and facilitating maintenance.

[0013] Furthermore, both the first relief valve and the second relief valve are pilot-operated relief valves.

[0014] Furthermore, the one-way valve is installed in the first overflow oil circuit. The inlet of the one-way valve is connected to the drain port of the first overflow valve, and the outlet of the one-way valve is connected to the second oil circuit. This is used to prevent hydraulic oil from flowing from the first overflow oil circuit to the drain port of the first overflow valve when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder. This avoids hydraulic oil impacting the drain port of the first overflow valve, which could damage the drain port of the first overflow valve and extend the service life of the first overflow valve.

[0015] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes: a first one-way throttle valve and a second one-way throttle valve;

[0016] The first one-way throttle valve and the second one-way throttle valve are connected in series in the first oil circuit, located between the other end of the first oil circuit and one end of the first overflow oil circuit, and arranged in opposite directions;

[0017] The first one-way throttle valve is used to control the flow rate of the first oil circuit when the hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder, and the first one-way throttle valve does not have a throttling effect when the hydraulic oil in the rod chamber of the hydraulic cylinder flows back from the first oil circuit.

[0018] The second one-way throttle valve is used to control the flow rate of the first oil circuit when the hydraulic oil in the rod chamber of the hydraulic cylinder flows back from the first oil circuit, and the second one-way throttle valve does not have a throttling effect when the hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder.

[0019] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes a first hydraulically controlled check valve. The first hydraulically controlled check valve is disposed in the first oil circuit. The oil outlet of the first hydraulically controlled check valve is connected to the rod chamber of the hydraulic cylinder and the first overflow oil circuit, respectively. The control oil port of the first hydraulically controlled check valve is connected to the second oil circuit. It is used to prevent hydraulic oil from flowing back from the first oil circuit when oil is supplied from the first oil circuit to the rod chamber of the hydraulic cylinder, and does not have a check function when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder.

[0020] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes a return oil tank for recovering hydraulic oil, preventing hydraulic oil discharge from polluting the environment, and maintaining the pressure balance of the combined control system of the hydraulic cylinder and the hydraulic motor.

[0021] The other end of the first oil circuit (i.e., the end not connected to the rod chamber of the hydraulic cylinder) and the other end of the second oil circuit (i.e., the end not connected to the rodless chamber of the hydraulic cylinder) can be selectively connected to the hydraulic oil source and the return oil tank, respectively.

[0022] Furthermore, the other end of the second overflow oil circuit is connected to the return oil tank or the other end of the first oil circuit (i.e., the end not connected to the rod chamber of the hydraulic cylinder).

[0023] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes: the hydraulic motor and a third oil circuit;

[0024] The hydraulic motor is installed on the third oil circuit. One end of the third oil circuit is connected to the other end of the first oil circuit (i.e., the end that is not connected to the rod chamber of the hydraulic cylinder), and the other end is connected to the return oil tank. It is used to supply oil to the hydraulic motor and to allow the hydraulic oil in the hydraulic motor to flow from the third oil circuit into the return oil tank.

[0025] The oil inlet of the hydraulic motor is connected to the other end of the first oil circuit (i.e., the end not connected to the rod chamber of the hydraulic cylinder), and the oil return port of the hydraulic motor is connected to the oil return tank, which is used for the transmission of the excavator head changing device.

[0026] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes a first drain oil circuit. The housing of the hydraulic motor is provided with a drain port. One end of the first drain oil circuit is connected to the drain port of the hydraulic motor, and the other end is connected to the second oil circuit. It is used to drain the hydraulic oil in the housing of the hydraulic motor when oil is supplied to the hydraulic motor from the third oil circuit.

[0027] Furthermore, a third check valve is provided on the first drain oil line. The inlet of the third check valve is connected to the drain port of the hydraulic motor, and the outlet of the third check valve is connected to the second oil line. This is used to prevent hydraulic oil from flowing from the first drain oil line to the drain port of the hydraulic motor when oil is supplied from the second oil line to the rodless chamber of the hydraulic cylinder.

[0028] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes a second drain oil circuit. One end of the second drain oil circuit is connected to the drain port of the hydraulic motor, and the other end is connected to the third oil circuit. It is connected between the return oil port of the hydraulic motor and the return oil tank, and is used to drain the hydraulic oil in the hydraulic motor housing when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder.

[0029] Furthermore, a fourth check valve is provided on the second drain oil line. The inlet of the fourth check valve is connected to the drain port of the hydraulic motor, and the outlet of the fourth check valve is connected to the third oil line. This is used to prevent hydraulic oil from flowing from the second drain oil line to the drain port of the hydraulic motor when the hydraulic oil in the hydraulic motor flows from the third oil line into the return oil tank.

[0030] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes a chain lubrication oil circuit. One end of the chain lubrication oil circuit is connected to the drain port of the hydraulic motor, and the other end is a chain lubrication oil port, which is used for the discharge of hydraulic oil in the hydraulic motor housing, and then the chain is lubricated by the hydraulic oil discharged from the chain lubrication oil port.

[0031] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes a back pressure check valve and a second hydraulically controlled check valve;

[0032] The back pressure check valve is installed on the third oil circuit. The oil inlet of the back pressure check valve is connected to the oil return port of the hydraulic motor and the second drain oil circuit, respectively. The oil outlet of the back pressure check valve is connected to the oil return tank. It is used to generate a pressure signal when the hydraulic oil passes through the back pressure check valve.

[0033] The second hydraulic control check valve is installed in the chain lubrication oil circuit. The oil inlet of the second hydraulic control check valve is connected to the chain lubrication oil port, the oil outlet of the second hydraulic control check valve is connected to the drain port of the hydraulic motor, and the control oil port of the second hydraulic control check valve is connected to the oil inlet of the back pressure check valve, for controlling the opening and closing of the chain lubrication oil circuit.

[0034] Furthermore, a third throttle valve is also provided on the chain lubrication oil circuit, which is used to control the flow rate of the chain lubrication oil circuit when the hydraulic oil in the hydraulic motor housing leaks out from the chain lubrication oil circuit, thereby controlling the flow rate of the first drain oil circuit or the second drain oil circuit.

[0035] By adopting the above technical solution, this utility model has the following beneficial effects:

[0036] This utility model provides a combined control system for a hydraulic cylinder and a hydraulic motor. By setting up a first overflow oil circuit and a second overflow oil circuit, and installing a first overflow valve and a second overflow valve on the first overflow oil circuit and the second overflow oil circuit respectively, the working pressure of the hydraulic cylinder is controlled by the first overflow valve and the second overflow valve respectively when supplying oil to the rod chamber and rodless chamber of the hydraulic cylinder. This simplifies the hydraulic circuit and hydraulic components set in the narrow space inside the excavator head changing device, reduces the cost and failure rate, and facilitates maintenance. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 Hydraulic schematic diagram of the combined control system of hydraulic cylinder and hydraulic motor provided for embodiments of this utility model;

[0039] Figure 2 A hydraulic schematic diagram of a combined control system for a hydraulic cylinder and a hydraulic motor provided for another embodiment of the present invention;

[0040] Figure 3 A hydraulic schematic diagram of a combined control system for a hydraulic cylinder and a hydraulic motor, provided in another embodiment of this utility model.

[0041] Figure label:

[0042] 1-First one-way throttle valve; 2-Second one-way throttle valve; 3-First hydraulically controlled one-way valve; 4-First relief valve; 5-One-way valve; 6-Hydraulic cylinder; 7-Hydraulic motor; 8-Back pressure one-way valve; 9-Second hydraulically controlled one-way valve; 10-Third throttle valve; 11-Chain lubrication port; 12-Fourth one-way valve; 13-Third one-way valve; 14-Second relief valve. Detailed Implementation

[0043] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0044] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] The present invention will be further explained below with reference to specific embodiments.

[0047] It should also be noted that the specific embodiments or implementation methods described below are a series of optimized settings listed by this utility model to further explain the specific utility model content, and these settings can be combined or used in conjunction with each other.

[0048] Example 1

[0049] like Figure 1As shown, this embodiment provides a combined control system for a hydraulic cylinder and a hydraulic motor, including: a hydraulic cylinder 6, a first oil circuit, a second oil circuit, a first overflow oil circuit, a first overflow valve 4, a second overflow oil circuit, and a second overflow valve 14; one end of the first oil circuit is connected to the rod chamber of the hydraulic cylinder 6, and is used to supply oil to the rod chamber of the hydraulic cylinder 6 or to discharge hydraulic oil from the rod chamber of the hydraulic cylinder 6; one end of the second oil circuit is connected to the rodless chamber of the hydraulic cylinder 6, and is used to discharge hydraulic oil from the rodless chamber of the hydraulic cylinder 6 or to supply oil to the rodless chamber of the hydraulic cylinder 6; one end of the first overflow oil circuit is connected to the first oil circuit, and the other end is connected to the second oil circuit; the first overflow valve 4 is disposed on the first overflow oil circuit. The second overflow valve 14 is configured to allow hydraulic oil in the rod chamber of the hydraulic cylinder 6 to overflow from the first overflow oil passage when the working pressure in the rod chamber of the hydraulic cylinder 6 is too high, thereby controlling the working pressure of the hydraulic cylinder 6 and maintaining its stability when oil is supplied from the first oil passage to the rod chamber of the hydraulic cylinder 6; one end of the second overflow oil passage is connected to the second oil passage; the second overflow valve 14 is provided on the second overflow oil passage and is used to allow hydraulic oil in the rodless chamber of the hydraulic cylinder 6 to overflow from the second overflow oil passage when the working pressure in the rodless chamber of the hydraulic cylinder 6 is too high, thereby controlling the working pressure of the hydraulic cylinder 6 and maintaining its stability when oil is supplied from the second oil passage to the rodless chamber of the hydraulic cylinder 6.

[0050] This application simplifies the hydraulic circuit and hydraulic components within the narrow space of the excavator head changing device by setting up a first overflow oil circuit and a second overflow oil circuit, respectively, and by setting up a first overflow valve 4 and a second overflow valve 14 on the first overflow oil circuit and the second overflow valve 14, respectively, to control the working pressure of the hydraulic cylinder 6 when supplying oil to the rod chamber and rodless chamber of the hydraulic cylinder 6, thereby reducing the cost and failure rate and facilitating maintenance.

[0051] Based on the above technical solution, and further preferably, both the first relief valve 4 and the second relief valve 14 are pilot-operated relief valves; the oil supply pressure of the combined control system of the hydraulic cylinder and the hydraulic motor is usually the working pressure of the hydraulic motor 7. When the working pressure of the hydraulic cylinder 6 exceeds the maximum working pressure of the hydraulic cylinder 6, the hydraulic oil in the rod chamber of the hydraulic cylinder 6 overflows from the first relief oil circuit, or the hydraulic oil in the rodless chamber of the hydraulic cylinder 6 overflows from the second relief oil circuit; the pilot-operated relief valve has high precision and can accurately set the relief pressure, thereby precisely controlling the working pressure of the hydraulic cylinder 6.

[0052] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor further includes: a first one-way throttle valve 1 and a second one-way throttle valve 2; the first one-way throttle valve 1 and the second one-way throttle valve 2 are connected in series in the first oil circuit, located between the other end of the first oil circuit and one end of the first overflow oil circuit, and arranged in opposite directions; the first one-way throttle valve 1 is used to control the flow rate of the first oil circuit when the hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder 6, and the first one-way throttle valve 1 does not have a throttling effect when the hydraulic oil in the rod chamber of the hydraulic cylinder 6 flows back from the first oil circuit; the second one-way throttle valve 2 is used to control the flow rate of the first oil circuit when the hydraulic oil in the rod chamber of the hydraulic cylinder 6 flows back from the first oil circuit, and the second one-way throttle valve 2 does not have a throttling effect when the hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder 6.

[0053] More preferably, the first one-way throttle valve 1 is composed of a first one-way valve and a first throttle valve connected in parallel; the first one-way valve is used to prevent hydraulic oil from flowing from the first oil circuit to the rod chamber of the hydraulic cylinder 6 through the first one-way valve when oil is supplied from the first oil circuit to the rod chamber of the hydraulic cylinder 6, and when hydraulic oil in the rod chamber of the hydraulic cylinder 6 is discharged, hydraulic oil flows back from the first oil circuit through the first one-way valve; the first throttle valve is used to control the flow rate of the first oil circuit when hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder 6 through the first throttle valve, and when hydraulic oil in the rod chamber of the hydraulic cylinder 6 flows back from the first oil circuit, the first throttle valve does not have a throttling effect.

[0054] More preferably, the second one-way throttle valve 2 is composed of a second one-way valve and a second throttle valve connected in parallel; the second one-way valve is used to prevent hydraulic oil from flowing back from the first oil circuit through the second one-way valve when the hydraulic oil in the rod chamber of the hydraulic cylinder 6 is discharged, and when the hydraulic oil is supplied from the first oil circuit to the rod chamber of the hydraulic cylinder 6, the hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder 6 through the second one-way valve; the second throttle valve is used to control the flow rate of the first oil circuit when the hydraulic oil in the rod chamber of the hydraulic cylinder 6 flows back from the first oil circuit through the second throttle valve, and when the hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder 6, the second throttle valve does not have a throttling effect.

[0055] In this embodiment, the combined control system of the hydraulic cylinder and the hydraulic motor further includes a first hydraulically controlled check valve 3. The first hydraulically controlled check valve 3 is disposed in the first oil circuit. The oil outlet of the first hydraulically controlled check valve 3 is connected to the rod chamber of the hydraulic cylinder 6 and the first overflow oil circuit, respectively. The control oil port of the first hydraulically controlled check valve 3 is connected to the second oil circuit. It is used to prevent hydraulic oil from flowing back from the first oil circuit when oil is supplied from the first oil circuit to the rod chamber of the hydraulic cylinder 6, and does not have a check function when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder 6.

[0056] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes a return oil tank T for recovering hydraulic oil, preventing hydraulic oil discharge from polluting the environment, and maintaining the pressure balance of the combined control system of the hydraulic cylinder and the hydraulic motor; the other end of the first oil circuit (i.e., port A) and the other end of the second oil circuit (i.e., port B) can be selectively connected to the hydraulic oil source and the return oil tank T, respectively.

[0057] When the other end of the first oil circuit (i.e., port A) is connected to the hydraulic oil source, and the other end of the second oil circuit (i.e., port B) is connected to the return oil tank T, the hydraulic oil source supplies oil from the first oil circuit to the rod chamber of the hydraulic cylinder 6, and the hydraulic oil in the rodless chamber of the hydraulic cylinder 6 flows into the return oil tank T from the second oil circuit, causing the push rod of the hydraulic cylinder 6 to retract; when the other end of the second oil circuit (i.e., port B) is connected to the hydraulic oil source, and the other end of the first oil circuit (i.e., port A) is connected to the return oil tank T, the hydraulic oil source supplies oil from the second oil circuit to the rodless chamber of the hydraulic cylinder 6, and the hydraulic oil in the rod chamber of the hydraulic cylinder 6 flows into the return oil tank T from the first oil circuit, causing the push rod of the hydraulic cylinder 6 to extend.

[0058] In this embodiment, the other end of the second overflow oil circuit is connected to the return oil tank T. When the working pressure of the rodless chamber of the hydraulic cylinder 6 is too high, the hydraulic oil in the rodless chamber of the hydraulic cylinder 6 overflows from the second overflow oil circuit and flows into the return oil tank T from the second overflow oil circuit.

[0059] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor further includes: a hydraulic motor 7 and a third oil circuit; the hydraulic motor 7 is disposed on the third oil circuit, one end of the third oil circuit is connected to the other end of the first oil circuit (i.e., oil port A), and the other end is connected to the return oil tank T, for supplying oil to the hydraulic motor 7, and for the hydraulic oil in the hydraulic motor 7 to flow from the third oil circuit into the return oil tank T; the oil inlet of the hydraulic motor 7 is connected to the other end of the first oil circuit (i.e., oil port A), and the oil return port of the hydraulic motor 7 is connected to the return oil tank T, for the transmission of the excavator head changing device.

[0060] More preferably, the combined control system of the hydraulic cylinder and the hydraulic motor further includes a first drain oil circuit. The housing of the hydraulic motor 7 is provided with a drain port. One end of the first drain oil circuit is connected to the drain port of the hydraulic motor 7, and the other end is connected to the second oil circuit. It is used to drain the hydraulic oil in the housing of the hydraulic motor 7 when oil is supplied to the hydraulic motor 7 from the third oil circuit.

[0061] In this embodiment, a third check valve 13 is provided on the first drain oil line. The oil inlet of the third check valve 13 is connected to the oil drain port of the hydraulic motor 7, and the oil outlet of the third check valve 13 is connected to the second oil line. It is used to prevent hydraulic oil from flowing from the first drain oil line to the oil drain port of the hydraulic motor 7 when oil is supplied from the second oil line to the rodless chamber of the hydraulic cylinder 6.

[0062] More preferably, the combined control system of the hydraulic cylinder and the hydraulic motor further includes a second drain oil circuit. One end of the second drain oil circuit is connected to the drain port of the hydraulic motor 7, and the other end is connected to the third oil circuit. It is connected between the return oil port of the hydraulic motor 7 and the return oil tank T, and is used to drain the hydraulic oil in the housing of the hydraulic motor 7 when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder 6.

[0063] In this embodiment, a fourth check valve 12 is provided on the second drain oil line. The inlet of the fourth check valve 12 is connected to the drain port of the hydraulic motor 7, and the outlet of the fourth check valve 12 is connected to the third oil line. It is used to prevent hydraulic oil from flowing from the second drain oil line to the drain port of the hydraulic motor 7 when the hydraulic oil in the hydraulic motor 7 flows from the third oil line into the return oil tank T.

[0064] When hydraulic oil is supplied from the third oil circuit to the hydraulic motor 7, the hydraulic oil in the hydraulic motor 7 flows from the third oil circuit into the return oil tank T. The hydraulic oil in the housing of the hydraulic motor 7 is discharged from the first drain oil circuit through the third check valve 13 and flows into the return oil tank T from the second oil circuit. When oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder 6, the pressure in the second oil circuit is greater than the pressure at the drain port of the hydraulic motor 7. The hydraulic oil in the housing of the hydraulic motor 7 cannot be discharged from the first drain oil circuit. The hydraulic oil in the housing of the hydraulic motor 7 is discharged from the second drain oil circuit through the fourth check valve 12 and flows into the return oil tank T from the third oil circuit.

[0065] Furthermore, the combined control system of the hydraulic cylinder and the hydraulic motor also includes a chain lubrication oil circuit. One end of the chain lubrication oil circuit is connected to the drain port of the hydraulic motor 7, and the other end is a chain lubrication oil port 11, which is used for the discharge of hydraulic oil in the housing of the hydraulic motor 7, and then the chain is lubricated by the hydraulic oil discharged from the chain lubrication oil port 11.

[0066] More preferably, the combined control system of the hydraulic cylinder and the hydraulic motor further includes a back pressure check valve 8 and a second hydraulically controlled check valve 9; the back pressure check valve 8 is disposed on the third oil circuit, the inlet of the back pressure check valve 8 is connected to the return port of the hydraulic motor 7 and the second drain oil circuit respectively, and the outlet of the back pressure check valve 8 is connected to the return oil tank T, for generating a pressure signal when the hydraulic oil passes through the back pressure check valve 8; the second hydraulically controlled check valve 9 is disposed on the chain lubrication oil circuit, the inlet of the second hydraulically controlled check valve 9 is connected to the chain lubrication oil port 11, the outlet of the second hydraulically controlled check valve 9 is connected to the drain port of the hydraulic motor 7, and the control port of the second hydraulically controlled check valve 9 is connected to the inlet of the back pressure check valve 8, for controlling the opening and closing of the chain lubrication oil circuit.

[0067] When hydraulic oil flows from the third oil circuit into the return oil tank T through the back pressure check valve 8, the back pressure check valve 8 opens, generating a pressure signal. The control port of the second hydraulic control check valve 9 receives the pressure signal, and the outlet of the second hydraulic control check valve 9 is connected to the inlet of the second hydraulic control check valve 9. The hydraulic oil in the housing of the hydraulic motor 7 flows from the drain port of the hydraulic motor 7 into the chain lubrication oil circuit and is discharged from the chain lubrication oil port 11 to lubricate the chain. When the back pressure check valve 8 is closed, the control port of the second hydraulic control check valve 9 does not receive a pressure signal, and the second hydraulic control check valve 9 prevents the hydraulic oil in the housing of the hydraulic motor 7 from flowing from the chain lubrication oil circuit to the chain lubrication oil port 11.

[0068] Furthermore, a third throttle valve 10 is provided on the chain lubrication oil circuit to control the flow rate of the chain lubrication oil circuit when the hydraulic oil in the housing of the hydraulic motor 7 leaks out from the chain lubrication oil circuit, thereby controlling the flow rate of the first drain oil circuit or the second drain oil circuit.

[0069] This invention simplifies the hydraulic circuit and components within the narrow space of the excavator head changing device by setting up a first overflow oil circuit and a second overflow oil circuit, respectively, and controls the working pressure of the hydraulic cylinder 6 when supplying oil to the rod chamber and rodless chamber of the hydraulic cylinder 6, respectively. This reduces the cost and failure rate, and facilitates maintenance.

[0070] Example 2

[0071] This embodiment is basically the same as embodiment 1, except that:

[0072] like Figure 2 As shown, this embodiment provides a combined control system for a hydraulic cylinder and a hydraulic motor. The other end of the second overflow oil circuit is connected to the other end of the first oil circuit (i.e., oil port A). When the working pressure of the rodless chamber of the hydraulic cylinder 6 is too high, the hydraulic oil in the rodless chamber of the hydraulic cylinder 6 overflows from the second overflow oil circuit and flows into the return oil tank T from the first oil circuit.

[0073] Example 3

[0074] This embodiment is basically the same as embodiment 1, except that:

[0075] like Figure 3 As shown in the figure, this embodiment provides a combined control system for a hydraulic cylinder and a hydraulic motor. The one-way valve 5 is installed in the first overflow oil circuit. The oil inlet of the one-way valve 5 is connected to the oil outlet of the first overflow valve 4, and the oil outlet of the one-way valve 5 is connected to the second oil circuit. It is used to prevent hydraulic oil from flowing from the first overflow oil circuit to the oil outlet of the first overflow valve 4 when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder 6. This avoids the hydraulic oil impacting the oil outlet of the first overflow valve 4, which could damage the oil outlet of the first overflow valve 4, and extends the service life of the first overflow valve 4.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A combined control system for a hydraulic cylinder and a hydraulic motor, characterized in that, include: Hydraulic cylinder, first oil circuit, second oil circuit, first relief oil circuit, first relief valve, second relief oil circuit and second relief valve; One end of the first oil circuit is connected to the rod chamber of the hydraulic cylinder, and is used to supply oil to the rod chamber of the hydraulic cylinder or to discharge hydraulic oil from the rod chamber of the hydraulic cylinder; One end of the second oil circuit is connected to the rodless chamber of the hydraulic cylinder, and is used for discharging hydraulic oil from the rodless chamber of the hydraulic cylinder or supplying oil to the rodless chamber of the hydraulic cylinder; One end of the first overflow oil circuit is connected to the first oil circuit, and the other end is connected to the second oil circuit; The first overflow valve is installed in the first overflow oil circuit and is used to allow the hydraulic oil in the rod chamber of the hydraulic cylinder to overflow from the first overflow oil circuit when the working pressure in the rod chamber of the hydraulic cylinder is too high. One end of the second overflow oil circuit is connected to the second oil circuit; The second overflow valve is installed in the second overflow oil circuit and is used to allow hydraulic oil in the rodless chamber of the hydraulic cylinder to overflow from the second overflow oil circuit when the working pressure of the rodless chamber of the hydraulic cylinder is too high.

2. The combined hydraulic cylinder and hydraulic motor control system of claim 1, wherein, Both the first relief valve and the second relief valve are pilot-operated relief valves.

3. The combined hydraulic cylinder and hydraulic motor control system of claim 1, wherein, It also includes a one-way valve, which is disposed in the first overflow oil circuit. The oil inlet of the one-way valve is connected to the oil drain port of the first overflow valve, and the oil outlet of the one-way valve is connected to the second oil circuit. It is used to prevent hydraulic oil from flowing from the first overflow oil circuit to the oil drain port of the first overflow valve when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder.

4. The combined hydraulic cylinder and hydraulic motor control system of claim 1, wherein, Also includes: First one-way throttle valve and second one-way throttle valve; The first one-way throttle valve and the second one-way throttle valve are connected in series in the first oil circuit, located between the other end of the first oil circuit and one end of the first overflow oil circuit, and arranged in opposite directions; The first one-way throttle valve is used to control the flow rate of the first oil circuit when the hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder, and the first one-way throttle valve does not have a throttling effect when the hydraulic oil in the rod chamber of the hydraulic cylinder flows back from the first oil circuit. The second one-way throttle valve is used to control the flow rate of the first oil circuit when the hydraulic oil in the rod chamber of the hydraulic cylinder flows back from the first oil circuit, and the second one-way throttle valve does not have a throttling effect when the hydraulic oil flows from the first oil circuit to the rod chamber of the hydraulic cylinder.

5. The combined hydraulic cylinder and hydraulic motor control system of claim 1, wherein, It also includes a first hydraulically controlled check valve, which is disposed in the first oil circuit. The oil outlet of the first hydraulically controlled check valve is connected to the rod chamber of the hydraulic cylinder and the first overflow oil circuit, respectively. The control oil port of the first hydraulically controlled check valve is connected to the second oil circuit. It is used to prevent hydraulic oil from flowing back from the first oil circuit when oil is supplied from the first oil circuit to the rod chamber of the hydraulic cylinder, and does not have a check function when oil is supplied from the second oil circuit to the rodless chamber of the hydraulic cylinder.

6. The combined hydraulic cylinder and hydraulic motor control system of claim 1, wherein, It also includes the return oil tank, hydraulic motor, and third oil circuit; The return oil tank is used for the recovery of hydraulic oil, preventing hydraulic oil from being discharged and polluting the environment, and maintaining the pressure balance of the joint control system of the hydraulic cylinder and the hydraulic motor. The other end of the first oil circuit and the other end of the second oil circuit can be selectively connected to the hydraulic oil source and the return oil tank, respectively; The hydraulic motor is installed on the third oil circuit. One end of the third oil circuit is connected to the other end of the first oil circuit, and the other end is connected to the return oil tank. It is used to supply oil to the hydraulic motor and to allow the hydraulic oil in the hydraulic motor to flow from the third oil circuit into the return oil tank. The oil inlet of the hydraulic motor is connected to the other end of the first oil circuit, and the oil return port of the hydraulic motor is connected to the oil return tank, which is used for the transmission of the excavator head changing device.

7. The combined hydraulic cylinder and hydraulic motor control system of claim 6, wherein, It also includes a first oil drain circuit, and the housing of the hydraulic motor is provided with an oil drain port. One end of the first oil drain circuit is connected to the oil drain port of the hydraulic motor, and the other end is connected to the second oil circuit, which is used to drain the hydraulic oil in the housing of the hydraulic motor when oil is supplied to the hydraulic motor from the third oil circuit.

8. The combined hydraulic cylinder and hydraulic motor control system of claim 7, wherein, A third check valve is provided on the first drain oil line. The inlet of the third check valve is connected to the drain port of the hydraulic motor, and the outlet of the third check valve is connected to the second oil line. It is used to prevent hydraulic oil from flowing from the first drain oil line to the drain port of the hydraulic motor when oil is supplied from the second oil line to the rodless chamber of the hydraulic cylinder.

9. The combined hydraulic cylinder and hydraulic motor control system of claim 6, wherein, It also includes a second drain oil passage, one end of which is connected to the drain port of the hydraulic motor, and the other end is connected to the third oil passage. It is connected between the return port of the hydraulic motor and the return oil tank, and is used to drain the hydraulic oil in the hydraulic motor housing when oil is supplied from the second oil passage to the rodless chamber of the hydraulic cylinder.

10. The combined hydraulic cylinder and hydraulic motor control system of claim 9, wherein, A fourth check valve is provided on the second drain line. The inlet of the fourth check valve is connected to the drain port of the hydraulic motor, and the outlet of the fourth check valve is connected to the third oil line. This is used to prevent hydraulic oil from flowing from the second drain line to the drain port of the hydraulic motor when the hydraulic oil in the hydraulic motor flows from the third oil line into the return oil tank.

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