DE112018002268T5 - Traction motor switching valve, traction motor and construction machine - Google Patents

Abstract

The present disclosure relates to the technical field of construction machines, in particular a traction motor switching valve, a traction motor and a construction machine. The traction motor switching valve as defined in the present disclosure includes a valve core, a first working oil opening, a second working oil opening, a third working oil opening, an external pilot oil opening, and a return oil opening, the valve core being from a low speed to a high speed and from switches from high speed to low speed with two different predetermined values, and both input pressure values of the engine after switching do not meet the switching limit conditions, which effectively prevents the traction motor from repeatedly switching between high and low speeds, and vibration of the construction machine under heavy load conditions reduced.

Description

RELEVANT REGISTRATIONS

The disclosure is based on that filed on December 1, 2017 Chinese application with application no. 201711246964.4 and claims their priority. The disclosure of this Chinese application is incorporated herein as a whole.

TECHNICAL AREA

The present disclosure relates to the technical field of construction machinery and, more particularly, to a traction motor switching valve, a traction motor and a construction machine.

STATE OF THE ART

Traction motors are used in construction machines such as Excavators often used to drive the construction machine to drive. A traction motor usually includes a motor and a swash plate control mechanism, the swash plate control mechanism adjusting a rotational speed of an output shaft of the motor by controlling the swash plate angle of the motor so that the traction motor has a two-speed switching function at a high speed and a low speed. In the low speed mode, the output speed of the traction motor is lower, but its displacement is larger, and a larger torque can be output under the same input power; while in the high speed mode, the output speed of the traction motor is higher, but its displacement is less and a smaller torque can be output under the same input power.

When excavators and other construction machinery are operating under heavy load conditions, e.g. on ramps or muddy mud or with a towing attachment etc., the traction motor often has to provide a higher drive torque, i.e. the traction motor must operate in a low speed mode so that the traction motor provides greater torque to prevent the phenomenon that no drive or weak drive occurs; when the driving resistance becomes lower, the driving motor must switch from the low speed mode to the high speed mode to improve the driving efficiency. Therefore, the traction motor must be able to switch between the high speed mode and the low speed mode.

In order to control the traction motor so that it automatically switches from the high speed mode to the low speed mode under heavy load conditions, the traction motor is usually equipped with a traction motor switching valve. By controlling whether high-pressure oil is supplied to the swash plate control mechanism, the traction motor switching valve controls whether the traction motor switches from the high speed mode to the low speed mode, thereby realizing the automatic switching function of the driving motor.

SUMMARY OF THE INVENTION

However, the inventor has found that the prior art traction motor shift valve generally determines whether the high pressure oil is supplied to the swash plate control mechanism to control the shift by detecting whether the actual pressure of the engine is in a high speed state exceeds a certain predetermined value. Since the maximum power provided by the prime mover (internal combustion engine) of the construction machine is a constant value, the output torque of the traction motor is proportional to the working pressure and the displacement, so under the same working conditions, after the motor has moved from high speed to has switched low speed, the pressure of the engine inlet opening will be lower than the pressure before switching, namely lower than the predetermined value, at which time the switching valve will automatically switch back to high speed mode, causing the traction motor to repeat under heavy load conditions switches between high speed and low speed, causing the construction machine to vibrate under heavy load conditions, which not only affects the life and safety of the switching valve itself, the drive motor and the construction machine as a whole, but also reduces the comfort of the product.

A technical problem to be solved by the present disclosure is thus to prevent the traction motor from repeatedly switching between the high speed and the low speed in order to reduce the vibration of the construction machine under heavy load conditions.

• der Ventileinsatz dafür ausgelegt ist, sich von der ersten Arbeitsposition in die zweite Arbeitsposition zu bewegen, wenn ein Öldruck der Rückführölöffnung niedriger ist als ein erster vorgegebener Wert P_C1, und der Ventileinsatz dafür ausgelegt ist, sich von der zweiten Arbeitsposition in die erste Arbeitsposition zu bewegen, wenn der Öldruck der Rückführölöffnung höher ist als ein zweiter vorgegebener Wert P_C2, wobei der erste vorgegebene Wert P_C1 nicht gleich dem zweiten vorgegebenen Wert P_C2 ist; und
• ein Öldruck der Rückführölöffnung ein erster Arbeitswert P_C3 ist, nachdem sich der Ventileinsatz von der ersten Arbeitsposition in die zweite Arbeitsposition bewegt hat, und ein Öldruck der Rückführölöffnung ein zweiter Arbeitswert P_C4 ist, nachdem der Ventileinsatz von der zweiten Arbeitsposition in die erste Arbeitsposition umgeschaltet hat, wobei die Beziehung zwischen dem ersten Arbeitswert P_C3 und dem zweiten vorgegebenen Wert P_C2 wie folgt lautet: P_C3<K₁P_C2, K₁≤1, und wobei die Beziehung zwischen dem zweiten Arbeitswert P_C4 und dem ersten vorgegebenen Wert P_C1 wie folgt lautet: P_C4>K₂P_C1, K₂≥1.

To solve the above-mentioned technical problem, a first aspect of the present disclosure provides a traction motor switching valve comprising a valve core, a first working oil opening, a second working oil opening, a third working oil opening, an external control opening and a return oil opening, the valve insert having a first working position and has a second working position; in the the first working position, the first working oil opening is blocked, and the second working oil opening is in communication with the third working opening; in the second working position, the first working oil opening is in communication with the third working oil opening, and the second working oil opening is blocked off; the first working oil port is for communication with an oil well, the second working oil port is for communication with an oil tank, and the third working oil port is for communication with a swash plate control mechanism of a traction motor; the external control oil port serves to direct the oil to act on a first axial end of the valve insert and allow the valve insert to tend to move from the first working position to the second working position, and the return oil opening serves to reduce the working pressure returning a motor of the traction motor to a second axial end of the valve core and allowing the valve core to generate a tendency to move from the second working position to the first working position; and the traction motor switching valve is designed such that:

• the valve core is designed to move from the first working position to the second working position when an oil pressure of the return oil opening is lower than a first predetermined value P _C1 , and the valve core is designed to move from the second working position to the first working position move when the oil pressure of the return oil port is higher than a second predetermined value P _C2 , the first predetermined value P _C1 not being equal to the second predetermined value P _C2 ; and
• an oil pressure of the return oil opening is a first working value P _C3 after the valve insert has moved from the first working position to the second working position, and an oil pressure of the return oil opening is a second working value P _C4 after the valve insert has switched from the second working position to the first working position , the relationship between the first work value P _C3 and the second predetermined value P _{C2 being} as follows: P _C3 <K ₁ P _C2 , K ₁ ≤1, and the relationship between the second work value P _C4 and the first predetermined value P _{C1 is} as follows: P _C4 > K ₂ P _C1 , K ₂ ≥1.

In some embodiments, the traction motor switch valve further includes a first chamber, a second chamber, and a third chamber, the first chamber in communication with the external control oil port, the third chamber in communication with the return oil port, the second chamber in communication with the third working oil port and is configured to switch to alternately communicate with the second working oil port and the first working oil port during the process of moving the valve core from the first working position to the second working position, and an effective pressure area of the second chamber is less than that the third chamber.

und der zweite Arbeitswert P_C4 wie folgt lautet: $P_{C4}=\frac{V_2}{V_1}{P}_{C2},$

wobei Px ein Öldruck der externen Steuerölöffnung ist, A₁, A₂ und A₃ jeweils effektive Druckwirkflächen der ersten Kammer, der zweiten Kammer und der dritten Kammer sind, F₁ und F₂ jeweils Wirkkräfte der Feder sind, die auf den Ventileinsatz in der ersten Arbeitsposition und in der zweiten Arbeitsposition ausgeübt werden, und V₁ und V₂ jeweils Verdrängungen des Motors in der ersten Arbeitsposition und in der zweiten Arbeitsposition sind.In some embodiments, the traction motor switch valve further includes a spring, the spring being disposed at the second axial end of the valve insert and exerting an active force on the valve insert that enables the valve insert to tend to move from the second working position to the first working position generate, where the first predetermined value P _{C1 is} as follows: P _C1 = (Px × A ₁ -F ₁ ) / A ₃ , the second predetermined value P _{C2 is} as follows: P _C2 = (Px × A ₁ -F ₂ ) / (A ₃ - A ₂ ), the first labor value P _{C3 is} as follows: $P_{C3}=\frac{V_1}{V_2}{\mathrm{<figure-callout\; id="1"\; label="P\; C"\; filenames="DE112018002268T5\_0016.png,DE112018002268T5\_0017.png"\; state="\{\{state\}\}">P\; </figure-callout>}}_C.$

and the second labor value P _{C4 is} as follows: ${\mathrm{<figure-callout\; id="4"\; label="P\; C"\; filenames="DE112018002268T5\_0016.png"\; state="\{\{state\}\}">P\; </figure-callout>}}_C=\frac{V_2}{V_1}{P}_{C2}.$

where Px is an oil pressure of the external control oil opening, A ₁ , A ₂ and A _{3 are} each effective pressure active surfaces of the first chamber, the second chamber and the third chamber, F ₁ and F _{2 are} each active forces of the spring, which act on the valve insert in the first working position and in the second working position, and V ₁ and V ₂ are displacements of the motor in the first working position and in the second working position, respectively.

In some embodiments, the second chamber and the third chamber are arranged on the valve insert and positioned at the first axial end and at the second axial end of the valve insert, respectively.

In some embodiments, a first piston chamber and a second piston chamber are provided at the first axial end and at the second axial end of the valve insert, respectively; a first piston is disposed in the first piston chamber and a second piston is disposed in the second piston chamber; the second chamber is positioned between the first piston and an inner wall of the first piston chamber, and the third chamber is positioned between the second piston and an inner wall of the second piston chamber.

In some embodiments, a first passage is disposed on the valve insert and the second chamber is in communication with one of the first working oil port and the second working oil port through the first port; and / or a second passage is arranged on the valve insert, and the third chamber is in communication with the return oil opening via the second passage.

In some embodiments, the traction motor switching valve comprises a first plug part, which is arranged at the second axial end of the valve insert; a spring of the traction motor switching valve is designed to rest between the first plug part and the second axial end of the valve insert and to exert an active force on the valve insert that enables the valve insert to generate the tendency of movement from the second working position to the first working position ,

In some embodiments, a spring receiving chamber is on the surface of the first connector part, i.e. adjacent to the valve core, and the spring is disposed in the spring receiving chamber.

In some embodiments, a first through hole is disposed on the first connector part, and the first through hole is in communication with the spring receiving chamber.

In some embodiments, a mounting groove is on the surface of the first connector part, i.e. away from the valve core.

In some embodiments, a throat portion is located at the first axial end of the valve insert.

In some embodiments, a depression is disposed on a peripheral surface of the throat portion.

A second aspect of the present disclosure provides a traction motor comprising a motor and a swash plate control mechanism that is drivingly connected to a swash plate of the motor, further comprising the traction motor switching valve of the present disclosure, the traction motor switching valve being disposed within a jacket of the motor.

In some embodiments, a second through hole is disposed on the jacket, the valve insert of the traction motor switching valve is arranged in the second through hole, and the first working oil opening, the second working oil opening, the third working oil opening, the external control opening and the return oil opening of the traction motor switching valve are all arranged on the inner wall of the jacket.

A third aspect of the present disclosure further provides a construction machine comprising the traction motor of the present disclosure.

Based on the improvement of the traction motor switching valve, the valve insert of the traction switching valve is designed to switch from a low speed to a high speed and from a high speed to a low speed with two different predefined values, and the input pressure values of the motor after Shifting is both designed to fail to meet the shifting boundary conditions, so the present disclosure effectively prevents the traction motor from repeatedly switching between high and low speeds and reduces vibration of the construction machine under heavy load conditions.

Other features and advantages of the present disclosure will become apparent from the detailed description of the exemplary embodiment of the present disclosure with reference to the following accompanying drawings.

list of figures

• 1 stellt ein Diagramm des hydraulischen Prinzips eines Fahrmotorsystems gemäß einer Ausführungsform der vorliegenden Offenbarung dar.
• 2 stellt eine Querschnittansicht dar, die den Ventileinsatz des Fahrmotor-Schaltventils von 1 in einer ersten Arbeitsposition zeigt.
• 3 stellt eine Querschnittansicht dar, die den Ventileinsatz des Fahrmotor-Schaltventils, wie in 1 dargestellt, in einer zweiten Arbeitsposition zeigt.
• 4 stellt eine schematische Ansicht dar, welche den Aufbau des Ventileinsatzes von 2 und 3 zeigt.

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions of the prior art, the drawings to be used in the embodiments or the description of the prior art are briefly described below. Obviously, the drawings in the following description are only some of certain embodiments of the present disclosure. It is possible for a person skilled in the art to obtain other drawings based on the drawings without any creative activity.

• 1 FIG. 13 illustrates a diagram of the hydraulic principle of a traction motor system according to an embodiment of the present disclosure.
• 2 FIG. 12 is a cross-sectional view showing the valve core of the traction motor switching valve of FIG 1 shows in a first working position.
• 3 FIG. 13 is a cross-sectional view showing the valve insert of the traction motor switching valve as in FIG 1 shown in a second working position.
• 4 is a schematic view showing the structure of the valve insert of 2 and 3 shows.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solutions of the embodiments of the present disclosure will now be clearly and fully described in further detail in connection with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments represent only a part and not the entirety of the embodiments of the present disclosure The following description of the at least one exemplary embodiment is provided for illustration only and is in no way intended to limit the present disclosure and its application or use. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without any creative activity fall within the scope of the present disclosure. Techniques, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, however, if appropriate, the techniques, methods, and devices should be considered as part of the specification as approved.

In describing the present disclosure, it is believed that the alignment or positional relationship provided by alignment words such as e.g. "Front, rear, up, down, left, right", "side, upright, vertical, horizontal" and "up, down" is generally based on the orientation or positional relationship shown in the drawings, which is only the more convenient Description of the present disclosure and the simplified description is used. In the absence of statements to the contrary, these alignment words are not intended to indicate or imply that the device or component referred to must have a specific orientation or must be constructed or operated in a specific orientation, so this cannot limit the scope of the present disclosure be understood; the alignment words "inside and outside" refer to the inside and outside of the outline of each component itself.

In describing the present disclosure, it is believed that the use of the words "first", "second" and the like to define the components only serves to facilitate the distinction between the corresponding components. Unless otherwise stated, the above words have no specific connotation and thus cannot be interpreted as limiting the scope of the present disclosure.

• der Ventileinsatz 1 dafür ausgelegt ist, sich von der ersten Arbeitsposition in die zweite Arbeitsposition zu bewegen, wenn ein Öldruck der Rückführölöffnung C niedriger ist als ein erster vorgegebener Wert P_C1, und der Ventileinsatz 1 dafür ausgelegt ist, sich von der zweiten Arbeitsposition in die erste Arbeitsposition zu bewegen, wenn ein Öldruck der Rückführölöffnung C höher ist als ein zweiter vorgegebener Wert P_C2, wobei der erste vorgegebene Wert P_C1 nicht gleich dem zweiten vorgegebenen Wert P_C2 ist; und
• ein Öldruck der Rückführölöffnung C ein erster Arbeitswert P_C3 ist, nachdem sich der Ventileinsatz 1 von der ersten Arbeitsposition in die zweite Arbeitsposition bewegt hat, und ein Öldruck der Rückführölöffnung C ein zweiter Arbeitswert P_C4 ist, nachdem der Ventileinsatz 1 von der zweiten Arbeitsposition in die erste Arbeitsposition umgeschaltet hat, wobei die Beziehung zwischen dem ersten Arbeitswert P_C3 und dem zweiten vorgegebenen Wert P_C2 wie folgt lautet: P_C3<K₁P_C2, K₁≤1, und wobei die Beziehung zwischen dem zweiten Arbeitswert P_C4 und dem ersten vorgegebenen Wert P_C1 wie folgt lautet: P_C4>K₂P_C1, K₂≥1.

1-4 show an embodiment of the present disclosure. With reference to 1-4 includes a traction motor switching valve 100 valve insert as provided by the present disclosure 1 , a first working oil opening Y , a second working oil opening L , a third working oil opening Z , an external control opening X and a return oil port C , the valve core 1 has a first working position and a second working position, the first working oil opening in the first working position Y is blocked off and the second working oil opening L in communication with the third working oil opening Z stands, and wherein in the second working position, the first working oil opening Y in communication with the third working oil opening Z stands and the second working oil opening L is cordoned off; the first working oil opening Y is used for communication with an oil well, the second working oil opening L is used for communication with an oil tank, and the third working oil opening Z is used to communicate with a swashplate control mechanism 500 the traction motor; the external control oil opening X serves to direct the control oil to a first axial end of the valve insert 1 act and it the valve core 1 to allow a tendency of movement from the first working position to the second working position to be generated, and the return oil opening C serves the actual working pressure of an engine 400 of the traction motor to a second axial end of the valve insert 1 attributed and it to the valve core 1 enable a tendency to move from the second working position to the first working position; and the traction motor switching valve 100 is designed in such a way that:

• the valve insert 1 is designed to move from the first working position to the second working position when an oil pressure of the return oil opening C is lower than a first predetermined value P _C1 , and the valve insert 1 is configured to move from the second working position to the first working position when an oil pressure of the return oil port C is higher than a second predetermined value P _C2 , the first predetermined value P _C1 not being equal to the second predetermined value P _C2 ; and
• an oil pressure of the return oil opening C a first work value P _C3 is after the valve insert 1 has moved from the first working position to the second working position, and an oil pressure of the return oil opening C a second work value P _C4 is after the valve insert 1 has switched from the second working position to the first working position, the relationship between the first working value P _C3 and the second predetermined value P _{C2 being} as follows: P _C3 <K ₁ P _C2 , K ₁ ≤1, and the relationship between the second work value P _C4 and the first predetermined value P _{C1 is} as follows: P _C4 > K ₂ P _C1 , K ₂ ≥1.

In the present disclosure, P _C1 and P _C2 are critical engine pressure values, respectively 400 , if that Driving motor switching valve 100 controls the traction motor to switch from a low speed to a high speed and from a high speed to a low speed; P _C3 and P _C4 are actual engine input _{pressure values} , respectively 400 when the traction motor switching valve 100 controls the traction motor to switch from a low speed to a high speed and from a high speed to a low speed; and K ₁ and K ₂ are safety factors for the traction motor to be stable at a high speed each after switching from a low speed to a high speed and stable at a low speed after switching from a high speed to a low speed his.

By means of an improvement in a traction motor switching valve 100 the present disclosure enables valve insert 1 of the traction motor switching valve 100 to switch from a low speed to a high speed and from a high speed to a low speed with two different predetermined values, and it enables the input pressure values of the engine 400 after shifting does not meet the shift limit conditions, so the present disclosure can effectively prevent the traction motor from repeatedly switching between high and low speeds, and reduce the vibration of the construction machine under heavy load conditions, which is beneficial for the life of the traction motor shift valve 100 to extend a driving motor and a construction machine, improve driving safety and increase comfort when using. In the present disclosure, preferably K ₁ <1 and / or K ₂ > 1, in this way, when after switching from a low speed to a high speed and / or from a high speed to a low speed, stabilization at Speed has occurred, the traction motor's safety factor is higher, so that the traction motor is more reliably prevented from repeatedly switching between high and low speeds, and the vibration of the construction machine is reduced more effectively under heavy load conditions, which is more favorable for the life of the traction motor switching valve 100 , to extend the driving motor and the construction machine, to improve driving safety and to increase comfort during use.

As a version of the traction motor switching valve 100 In the present disclosure, the traction motor switching valve 100 also a first chamber 1a , a second chamber 1b and a third chamber 1c comprise, the first chamber 1a in communication with the external control oil opening X stands, the third chamber 1c in communication with the return oil port C stands, the second chamber 1b in communication with the third working oil opening Z stands and switches to during the process of moving the valve core 1 from the first working position to the second working position alternating with the second working oil opening L and the first working oil opening Y to communicate, and being an effective pressure area of the second chamber 1b is smaller than that of the third chamber 1c ,

To allow the valve core 1 of the traction motor switching valve 100 controls the traction motor to switch from a low speed to a high speed and from a high speed to a low speed with two different predetermined values, respectively, and to enable both input pressure values of the motor 400 after switching does not meet the switching limit conditions, only the effective pressure effective surfaces of the first chamber therefore have to be present in the present disclosure 1a , the second chamber 1b and the third chamber 1c be set, which is of simple structure, low cost and high reliability. This is combined with the in 1-4 illustrated embodiment illustrated in more detail.

The present disclosure is made in connection with 1-4 described in more detail. For ease of understanding, the structure and operating principle of a traction motor system are first referred to in FIG 1 described.

As in 1 shown, a traction motor system comprises a traction motor, a traction motor switching valve 100 , a pressure selection valve 300 and a balance valve 200 etc., and the traction motor includes a motor 400 and a swash plate control mechanism 500 etc.

The swash plate control mechanism 500 in drive connection with the swashplate of the motor 400 serves to change the swivel angle of the swash plate by driving the swash plate to a swivel movement. As in 1 can be seen is the swashplate control mechanism 500 This embodiment specifically a hydraulic cylinder, the rod of which is connected to a swash plate. This drives when the rodless chamber of the swash plate control mechanism 500 is oiled, the swash plate control mechanism 500 the swashplate to pivot to a position with a smaller angle, which enables the traction motor to switch to the low speed mode; when the oil in the rodless chamber of the swash plate control mechanism 500 Flows back to the oil tank, the swash plate control mechanism drives 500 the swashplate to pivot to a larger angle position, which enables the traction motor to switch to the high speed mode.

The motor 400 is through the compensating valve 200 with oil holes A and B connected. If one from the oil hole A and the oil hole B the engine 400 When oil is supplied, the engine oil drain flows 400 through the other from the oil hole A and the oil hole B off, causing the engine 400 is driven to rotate clockwise or counterclockwise.

The traction motor switching valve 100 is used to control the rodless chamber of the swash plate control mechanism 500 to be switched to alternately communicate with one of an oil well and the oil tank, so that the switching of the traction motor between a high speed mode and a low speed mode can be controlled by controlling whether the rodless chamber of the swash plate control mechanism 500 Oil is supplied. As in 1 shown, the traction motor switching valve is in the embodiment 100 in communication with the rodless chamber of the swash plate control mechanism 500 , and through the pressure selection valve 300 it is in communication with the compensating valve 200 , In particular is the pressure selection valve 300 a shuttle valve; the first working oil opening Y of the traction motor switching valve 100 is in communication with the outlet of the pressure selection valve 300 , and the two inlets of the pressure selection valve 300 are through the compensating valve 200 each with the oil opening A and the oil hole B connected; the second working oil opening L of the traction motor switching valve 100 is in communication with the oil tank; and the third working oil opening Z of the traction motor switching valve 100 is in communication with the rodless chamber of the swash plate control mechanism 500 ,

Due to the arrangement of the pressure selection valve 300 can the first working oil opening Y always in communication with the larger of the oil hole A and the oil hole B stand. Because the greater pressure value of the oil opening A and the oil hole B an oil source pressure and meanwhile an input pressure or an actual working pressure of the engine 400 is the first working oil opening Y always in communication with the oil well, and the pressure value P _{Y of} the first working oil opening Y is actually equal to the actual working pressure value of the engine 400 ,

To the traction motor switching valve 100 to enable the rodless chamber of the swash plate control mechanism 500 control to be switched to alternately communicate with one of the oil well and the oil tank points as in 1 shown, the traction motor switching valve 100 a first working position (the left position in 1 ) and a second working position (the right position in 1 ) on. How from 1 can be seen, the first working oil opening is in the first working position Y cordoned off, and the second working oil port L is in communication with the third working oil opening Z , in this way the rodless chamber of the swash plate control mechanism 500 through the traction motor switching valve 100 communicated with the oil tank so that the pressure of the rodless chamber of the swash plate control mechanism 500 is reduced, and the cylinder rod of the swash plate control mechanism 500 is retracted under the reaction force of the swash plate, thereby driving the swash plate from the vertical direction to the horizontal direction in 1 to pivot, which increases the swivel angle of the swash plate to a maximum, reducing the speed of the output shaft of the motor 400 to a minimum, and which further enables the traction motor to operate in the low speed mode; the first working oil opening is in the second working position Y in communication with the third working oil port Z, and the second working oil port L is locked, in this way the rodless chamber of the swash plate control mechanism 500 through the traction motor switching valve 100 communicated with the oil well, and high pressure oil flows through the traction motor switching valve 100 into the rodless chamber of the swash plate control mechanism 500 , causing the cylinder rod of the swash plate control mechanism 500 is pressed to extend outward, the swash plate is driven to move in the vertical direction 1 to pivot, the swivel angle of the swash plate is reduced to a minimum and the speed of the output shaft of the motor 400 is increased to a maximum, and which also enables the traction motor to operate in high speed mode. It can be seen that the first working position and the second working position of the valve insert 1 each correspond to a low-speed mode (a low-speed working state, which is also referred to as the first working state) and a high-speed mode (a high-speed working state, which is also referred to as the second working state) of the traction motor.

It also includes how out 1 can be seen, the traction motor switching valve 100 an external control oil port X and a return oil port C , The external control oil opening X serves as a pilot control oil port for directing oil to the traction motor switching valve 100 , so that the traction motor switching valve 100 is controlled to switch from the first working position to the second working position. The return oil opening C serves to return the working pressure of the engine 400 of the traction motor to the valve insert 1 to the traction motor switching valve 100 to facilitate, depending on the actual driving load of the engine 400 to switch between the first working position and the second working position, whereby the traction motor is more precisely controlled to complete the switching depending on the actual needs. As described above, as it presses the first oil opening Y and the return oil port C actually the actual working pressure of the engine 400 is the pressure P _{Y of} the first working oil opening Y equal to the pressure Pc of the return oil opening C ,

In the prior art, there is only one critical condition for the traction motor switching valve for controlling the switching of the traction motor, ie the working pressure of the motor reaches a predetermined value, namely the pressure Pc of the return oil opening C is equal to a predetermined value, which means that the prior art traction motor switching valve accomplishes the control of switching from high speed to low speed and from low speed to high speed depending on the same predetermined value. The problem is as follows: since the maximum input power of the traction motor is a constant value and the output torque of the traction motor is proportional to the working pressure and displacement, the pressure of the motor inlet port after switching from the high speed to the low speed is lower than the predetermined value, at this time, the critical condition for switching from the low speed to the high speed is satisfied, whereby the drive motor switching valve controls the drive motor to automatically switch back to the high speed mode, but after the switch back to the high speed, the pressure of the Motor input opening will rise to the predetermined value and the critical condition for switching from high speed to low speed is now fulfilled, so that the traction motor switching valve controls the traction motor to automatically return to the low mode low speed. This process is repeated so that the traction motor is not kept in the desired low speed mode, but repeatedly switches between the high and low speeds, causing the construction machine to vibrate under heavy load conditions, which not only increases the life and safety of the switching valve itself, of the traction motor and the whole construction machine, but also reduces the comfort of the product.

In this embodiment, in order to solve the problem that the traction motor repeatedly switches between the high and the low speed, the following is with reference to FIG 2-4 the structure of the traction motor switching valve is described in detail 100 improved.

As in 2-3 shown, is a traction motor switching valve in this embodiment 100 in a coat 5 of the motor 400 arranged and comprises a valve insert 1 , a first piston 21 , a second piston 22 , a first plug part 31 , a second connector part 32 , a feather 4 , a first working oil opening Y , a second working oil opening L, a third working oil opening Z, an external control oil opening X , a first chamber 1a , a second chamber 1b and a third chamber 1c ; in addition, the traction motor switching valve includes 100 no valve body, but uses the jacket 5 as the valve body, and the valve insert 1 of the traction motor switching valve 100 is right inside the coat 5 arranged during the first working oil opening Y , the second working oil opening L , the third working oil opening Z , the external control oil opening X and the traction motor shift valve return oil port 100 all on the inside wall of the mantle 5 are arranged. Due to the arrangement of the traction motor switching valve 100 inside the mantle 5 are the traction motor switching valve 100 and the engine 400 integrated into a single structure so that the structure is more compact and the space taken up is reduced. By using the coat 5 as a valve body, it is not necessary to separately provide a special valve body in order to use the valve 1 and the oil openings of the traction motor switching valve 100 record, which further simplifies the structure, saves costs and simplifies maintenance. In particular, it's like 3 can be seen to the arrangement of the valve insert 1 in the coat 5 to facilitate, in the embodiment, a second through hole 51 on the coat 5 arranged, the valve core 1 in the second through hole 51 is arranged. Because the second through hole 51 to accommodate the valve insert 1 not only is processing easier, but also disassembly and assembly of the valve insert 1 facilitated. The second through hole 51 can on the back cover of the jacket 5 (ie the rear cover of the engine). The valve insert 1 is moved to toggle between the first working position (the right position in 2-3 ) and the second working position (the left position in 2-3 ) of the traction motor switching valve 100 to accomplish the on / off state of the first working oil opening Y , the second working oil opening L and the third working oil opening Z of the traction motor switching valve 100 to control. As in 3 shown, in the embodiment has the valve insert 1 a first axial end (ie a right end in the figure) and a second axial end (ie a left end in the figure), and as in FIG 4 shown are the first axial end and the second axial end of the valve insert 1 each with a first piston chamber 1f and a second piston chamber 1g Mistake. The effective pressure area of the first piston chamber 1f is smaller than that of the second piston chamber 1g , It is not difficult to understand that the first axial end and the second axial end are not on the two axial end surfaces of the valve insert herein 1 are limited, but can each include a section.

How through 2 and 3 shown, are the first piston in this embodiment 21 and the second piston 22 each in the first piston chamber 1f and the second piston chamber 1g , Freely sliding sealing strips are between the first piston 21 and an inner wall of the first piston chamber 1f as well as between the second piston 22 and an inner wall of the second piston chamber 1g educated. During the process of moving the valve core 1 The first piston moves from the first working position to the second working position 21 relative to the first piston chamber 1f extended, and the second piston 22 becomes relative to the second piston chamber 1g retracted during the process of moving the valve core 1 the first piston from the second working position to the first working position 21 relative to the first piston chamber 1 is retracted and the second piston 22 relative to the second piston chamber 1g is extended. Based on the above arrangements, as from 2 and 3 can be seen sealing chambers, each as a chamber 1b and third chamber 1c be referred to between the first piston 21 and an inner wall of the first piston chamber 1f and between the second piston 22 and an inner wall of the second piston chamber 1g educated. That is, in the embodiment, the second chamber 1b and the third chamber 1c on the valve insert 1 arranged and each at the first axial end and at the second axial end of the valve insert 1 positioned. The effective pressure area of the second chamber 1b is that of the first piston chamber 1f , the effective pressure effective area of the third chamber 1c is that of the second piston chamber 1g , and the effective pressure effective area of the first piston chamber 1f is smaller than that of the second piston chamber 1g , thus the effective pressure effective area of the second chamber 1b smaller than that of the third chamber 1c ,

In addition, as in 2 and 3 shown in the embodiment, the second chamber 1b and the third chamber 1c designed to communicate with all oil ports so that the third chamber 1c in communication with the return oil port C stands; the second chamber 1b is in communication with the third working oil opening Z and communicates during the process of moving the valve core 1 from the first working position to the second working position in succession with the second working oil opening L and the first working oil opening Y , ie the second chamber 1b communicates with the third working oil opening Z and the second working oil opening L when the valve core 1 is in the first working position (as in 2 shown), and the second chamber 1b communicates with the third opening Z and the first working oil opening Y when the valve core 1 is in the second working position (as in 3 ) Shown.

To it the second chamber 1b to facilitate with the second working oil opening L or the first working oil opening Y to communicate is like in 4 shown, in the embodiment a first passage 1d on the valve insert 1 arranged, the second chamber 1b through the first passage 1d with one from the first working oil opening Y and the second working oil opening L is brought into communication. As in 2 shown, the second chamber is in the first working position 1b about the first passage 1d in communication with the second working oil opening L ; and as in 3 shown, the second chamber is in the second working position 1b about the first passage 1d in communication with the first working oil opening Y , Similarly, it is the third chamber 1c to facilitate with the return oil port C to communicate in this embodiment as in 4 shown a second passage 1e on the valve insert 1 arranged, the third chamber 1c through the second passage 1e with the return oil opening C is brought into communication. In particular, is out 4 can be seen that both the second chamber 1b as well as the third chamber 1c along the axial direction of the valve insert 1 extend and that both the first passage 1d as well as the second passage 1e along the radial direction of the valve insert 1 extend so that the arrangement of the two chambers and the two channels on the valve insert 1 makes more sense and is more compact and processing is more practical.

Furthermore, as in 4 shown, in this embodiment, a constriction section at the first axial end of the valve insert 1 arranged. This way it is when the valve insert 1 must be dismantled, for the worker or the dismantling tool easy to get into the second through hole 51 to extend to force on the valve core 1 exercise so the valve core 1 easier from the second through hole 51 can be taken what the disassembly of the valve core 1 facilitated. It is also over 4 evident that further a deepening 15 is arranged on a circumferential surface of the constriction section. Because the deepening 15 Providing more convenience in exerting force on the throat section becomes the difficulty in disassembling the valve core 1 through the deepening 15 further decreased.

In addition, as in 2 and 3 shown, in the embodiment, the first connector part 31 and the second connector part 32 in each case at the second axial end and at the first axial end of the valve insert 1 arranged, the first plug part 31 and the second connector part 32 both with the coat 5 are connected and separately on the second axial end side of the valve insert 1 and the first axial end side of the valve insert 1 are arranged around the second axial end side of the valve insert 1 seal and the first axial end side of the valve insert 1 seal.

How from 2 and 3 can be seen is the first connector part 31 into the second through hole 51 screwed and at the second axial end of the valve insert 1 positioned around the second axial end of the valve core 1 seal. Specifically, the outer peripheral surface of the first connector part 31 fully threaded, and the inner wall of the corresponding portion of the second through hole 51 is also provided with screw threads, so that the first connector part 31 by the interaction of the screw threads in the second through hole 51 can be screwed.

Furthermore, as in 2 and 3 shown, also a mounting groove 31b on the surface of the first connector part 31 away from the valve core 1 intended. The mounting groove 31b is arranged to disassemble and assemble the first connector part 31 easier, which protrudes more when the first connector part 31 in the coat 5 is screwed. Because of the mounting groove 31b the tool can be inserted into the mounting groove 31b be inserted when the first connector part 31 disassembled or assembled, and then the first connector part 31 to the inside of the second through hole 51 of the coat 5 or to the outside of the second through hole 51 screwed to the disassembly and assembly of the first connector part 31 to achieve what is more practical and leads to greater efficiency in disassembly and assembly.

In addition, the first connector part 31 in the embodiment also designed for a spring 4 to support. The feather 4 lies between the first connector part 31 and the second axial end of the valve insert 1 to the valve core 1 to force a tendency to move from the second working position to the first working position. In particular, the arrangement of the spring 4 to facilitate, as in 2 and 3 shown, a spring receiving chamber in this embodiment 31c on the surface of the first connector part 31 , ie adjacent to the valve insert 1 , arranged, the spring 4 in the spring receiving chamber 31c is arranged and between the bottom wall of the spring receiving chamber 31c and the second axial end of the valve insert 1 rests in this way is the spring 4 designed for the valve core 1 to exert an active force that it the valve insert 1 allows you to move back from the second working position to the first working position. Furthermore, according to the combination of 2-4 a feather seat 16 at the second axial end of the valve insert 1 provided the spring 4 on the spring seat 16 is deferred to the valve core 1 to be connected, and a shaft shoulder is on the adjacent section between the spring seat 16 and the valve insert 1 provided the spring 4 rests on the shaft shoulder so that the spring 4 can be compressed or stretched to change the elastic force that occurs during the process of movement of the valve core 1 between the first working position and the second working position on the valve insert 1 is exercised. However, it is easy to understand that there is a spring chamber between the spring seat 16 , the first connector part 31 and the inner wall of the second through hole 51 is formed.

Furthermore, as in 2 and 3 shown, in this embodiment, a first through hole 31a on the first connector part 31 arranged, the first through hole 31a in communication with the spring receiving chamber 31c stands. This not only facilitates disassembly, but also oil return. In particular, the first through hole extends 31a along the axial direction of the valve insert 1 , so that the spring receiving chamber 31c through the first through hole 31a of shorter length can communicate with the outside. Thus, the structure is simpler and the oil return is more practical.

As in 2 and 3 shown, is the second connector part in the embodiment 32 into the second through hole 51 screwed and at the first axial end of the valve insert 1 arranged around the first axial end of the valve insert 1 seal. Specifically, the entire outer peripheral surface of the second connector part 32 provided with screw threads, and the inner wall of the corresponding portion of the second through hole 52 is also provided with screw threads, so that the second connector part 32 in cooperation with the screw threads in the second through hole 51 can be screwed.

As can be seen, the first connector part is in the embodiment 31 and the second connector part 32 on opposite sides in the axial direction of the second through hole 51 screwed. The screw connection creates the sealing effect of the first connector part 31 and the second connector part 32 improved. In addition, as in 2 and 3 shown, in this embodiment, the first chamber 1a between the first axial end of the valve insert 1 and the second connector part 32 positioned. In particular, the first chamber is located 1a between the first axial end of the valve insert 1 , the second connector part 32 , the first piston 21 and the inner wall of the second through hole 51 , The first chamber 1a is in communication with the external control oil opening X , so that through the external control oil opening X imported control oil into the first chamber 1a enters and onto the first axial end of the valve insert 1 acts on what it is the valve core 1 allows to generate a tendency of movement from the first working position to the second working position, thereby reducing the valve core 1 is facilitated under the control of the external control oil opening X to switch from the first working position to the second working position. To further improve the sealing effect, as in 2 shown, a sealing ring 6 between the second connector part 32 and the coat 5 arranged, the sealing ring 6 a tighter seal for the first chamber 1a can achieve. In summary, the first chamber is in the embodiment 1a between the first axial end of the valve insert 1 and the second connector part 32 positioned and in communication with the external control oil opening X ; the second chamber 1b and the third chamber 1c are on the valve insert 1 positioned and at the first axial end and at the second axial end of the valve insert 1 positioned, the third chamber 1c in communication with the return oil port C stands and the second chamber 1b in communication with the third working oil opening Z stands and during the process of moving the valve core 1 from the first working position to the second working position in succession with the second working oil opening L and the first working oil opening Y communicated.

In particular is off 2-4 evident that the valve insert 1 comprises four sealing sections along the axial direction, namely in each case a first sealing section 11 , a second sealing section 12 , a third section 13 and a fourth sealing section 14 , which are distributed in series from the first axial end to the second axial end, the four sealing portions slidingly close to the inner wall of the second through hole 51 are arranged. There is a narrowed section between adjacent sealing sections. This way, during the movement of the valve core 1 the communication relationship between the first chamber between the first working position and the second working position 1a , the second chamber 1b , the third chamber 1c and all oil openings through the four sealing sections of the valve insert 1 controlled.

As in 2 is shown when the valve insert 1 in the first working position (the position on the far right in the figure), the inner wall surface of the second through hole 51 between the first chamber 1a and the second working oil opening L through the first sealing section 11 sealed so that the first chamber 1a from the second working oil opening L is insulated, ensuring that the first chamber 1a only with the external control oil opening X is brought into communication; meanwhile, the inner wall surface of the second through hole 51 between the second chamber 1b and the first working oil opening Y through the second sealing section 12 sealed, and the throat portion between the first sealing portion 11 and the second sealing section 12 keeps distance from the inner wall surface of the second through hole 51 between the second chamber 1b and the second working oil opening L , causing the second chamber 1b with the second working oil opening L is brought into communication and from the first working oil opening Y is isolated; the inner wall surface of the second through hole 51 between the first working oil opening Y and the third chamber 1c is through the third sealing section 13 sealed, the constriction section between the third sealing section 13 and the fourth sealing section 14 keeps distance from the inner wall surface of the second through hole 51 between the third chamber 1c and the return oil port C , and the inner wall surface of the second through hole 51 between the return oil opening C and the spring chamber is through the fourth sealing section 14 sealed, creating the third chamber 1c both from the first working oil opening Y as well as the spring chamber is isolated and only with the return oil opening C is brought into communication.

As in 3 is shown when the valve insert 1 in the second working position (the leftmost position in the figure), the inner wall surface of the second through hole 51 between the first chamber 1a and the second working oil port L still through the first sealing portion 11 sealed, creating the first chamber 1a from the second working oil opening L is isolated and the first chamber 1a only with the external control oil opening X is in communication; in contrast, the inner wall surface of the second through hole 51 between the second chamber 1b and the second working oil opening L through the first sealing section 11 sealed, and the throat portion between the first sealing portion 11 and the second sealing section 12 keeps distance from the inner wall surface of the second through hole 51 between the second chamber 1b and the first working oil opening Y so the second chamber 1b is switched to in communication with the first working oil opening Y to stand, but from the second working oil opening L to be isolated; although the third sealing section 13 and the fourth sealing section 14 moving to the left, the throat section stops between the third sealing section 13 and the fourth sealing section 14 still distance from the inner wall surface of the second through hole 51 between the third chamber 1c and the return oil port C , meanwhile, the inner wall surface of the second through hole 51 between the first working oil opening Y and the third chamber 1c still through the third sealing section 13 sealed, and the inner wall surface of the second through hole 51 between the return oil opening C and the spring chamber is still through the fourth sealing section 14 sealed, creating the third chamber 1c still from both the first working oil opening Y as well as the spring chamber is isolated and only with the return oil opening C is in communication.

It can be seen that in this embodiment, when the valve core 1 is in the first working position, the first chamber 1a in communication with the external control oil opening X stands; the second chamber 1b is in communication with the second working oil opening L and the third working oil opening Z , however, is from the first working oil opening Y isolated, and the third chamber 1c is in communication with the return oil opening C ; and when the valve core 1 is in the second working position, the first chamber 1a in communication with the external control oil opening X , the second chamber 1b is in communication with the first working oil opening Y and the third working oil opening Z , however, is from the second working oil opening L isolated, and the third chamber 1c is in communication with the return oil opening C ,

The principle and the limit conditions for the control of the circuit by the traction motor switching valve are now described below 100 in the embodiment with reference to FIG 2 and 3 described.

First, for the sake of simplicity of description, the pressures of the first working oil opening Y , the second working oil opening L , the third working oil opening Z , the external control oil opening X and the return oil port C each defined as P _Y , P _L , P _Z , P _X and P _C , the effective pressure effective areas of the chamber 1a , the second chamber 1b and the third chamber 1c are defined as A ₁ , A ₂ and A ₃ , respectively, the forces exerted by the spring in the first working position and in the second working position 4 on the valve insert 1 exercised are defined as F ₁ and F ₂ , respectively, and the displacements of the motor 400 in the first working position and in the second working position are defined as V ₁ and V ₂ , respectively. Because the second working oil opening L in communication with the oil tank, it can be assumed that P _L = 0. Moreover, as mentioned above, the pressures of the first working oil port Y and the return oil port C actually the actual working pressures of the engine 400 , therefore: P _Y = P _C.

Based on what has been said above, as in 2 shown and mentioned above when the valve core 1 is in the first working position, the first chamber 1a in communication with the external control oil opening X , the second chamber 1b is in communication with the second working oil opening L and the third working oil opening Z , the third chamber 1c is in communication with the return oil opening C , and the elastic force of the spring 4 is F ₁ , this is under the condition that the influence of hydraulic force and friction on the sliding of the valve core 1 in the second through hole 51 the force equalization equation of the valve insert is ignored 1 received at this time as follows: $$Px\times A_1+P_L\times A_2=P_C\times A_3+{\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="DE112018002268T5\_0016.png,DE112018002268T5\_0017.png"\; state="\{\{state\}\}">F</figure-callout>}}_1$$

Since P _L = 0, it can be deduced that under the effect of the control pressure Px the external control oil opening X to the valve core 1 pushing from the first working position to the second working position, or in other words to switch the traction motor from the low speed mode to the high speed mode, the pressure P _C (the actual working pressure of the motor 400 ) of the return oil opening C Should: $$P_C<\left(Px\times A_1-F_1\right)/A_3$$

It is also known that under the effect of the control pressure px the external control oil opening X the boundary condition (as a boundary condition 1 to switch the drive motor from the low speed mode to the high speed mode should: $${\mathrm{<figure-callout\; id="1"\; label="P\; C"\; filenames="DE112018002268T5\_0016.png,DE112018002268T5\_0017.png"\; state="\{\{state\}\}">P\; </figure-callout>}}_C=\left(Px\times A_1-F_1\right)/A_3$$

P _C1 is referred to as the first predetermined value. This way, when the pressure of the return oil port C the valve insert is lower than the first predetermined value P _C1 1 moved from the first working position to the second working position.

As in 3 shown and mentioned above, when the valve insert 1 in the second working position, the first chamber 1a in communication with the external control oil opening X , the second chamber 1b is in communication with the first working oil opening Y and the third working oil opening Z, the third chamber 1c is in communication with the return oil port C, and the elastic force of the spring 4 is F ₂ , therefore, under the condition that the influence of the hydraulic force and the Friction on the sliding of the valve insert 1 in the second through hole 51 the force equalization equation of the valve insert is ignored 1 received at this time as follows: $$Px\times A_1+P_Y\times A_2=P_C\times A_3+F_2$$

Since P _Y = P _C , the following can be deduced: To enable the valve core to move from the second working position to the first working position, that is, to allow the traction motor to move from the high speed mode to the low speed mode the pressure Pc (the actual working pressure of the engine 400 ) of the return oil opening C Do the following: $$P_C>\left(Px\times A_1-F_2\right)/\left(A_3-A_2\right)$$

It is also known that the boundary condition (as a boundary condition 2 to switch the drive motor from the high-speed mode to the low-speed mode should: $$P_{C2}=\left(Px\times A_1-F_2\right)/\left(A_3-A_2\right)$$

P _C2 is referred to as the second predetermined value. When the pressure of the return oil opening C is higher than a first predetermined value P _C2 , the valve insert moves 1 in this way from the second working position to the first working position.

In order to avoid the repeated switching caused by the switching based on the same predetermined value, the first predetermined value and the second predetermined value in the embodiment are set to be unequal, whereby based on the formula (3) and the formula (6) the corresponding relationship between the areas A ₁ , A ₂ and A _{3 of} the three chambers is achieved.

Furthermore, in the embodiment, based on the displacement of the traction motor in the high speed mode and the low speed mode, the areas A ₁ , A ₂ and A _{3 of} the three chambers are further configured to the working pressure values of the engine 400 after switching to control such that the working pressure value of the engine 400 after switching from low speed mode to high speed mode, the limit condition 2 not met, causing the engine 400 as expected is kept stable in high speed mode, and the working pressure value of the engine 400 after switching from high speed mode to low speed mode, the limit condition 1 not met, causing the engine 400 kept stable in the low speed mode as expected, which more effectively prevents the phenomenon of repeated switching between the high speed and the low speed.

For the sake of simplicity of description, the oil pressure of the return oil port C (ie the working pressure of the engine 400 ) after the movement of the valve insert 1 from the first working position to the second working position (ie the switching of the traction motor from the low speed to the high speed) is defined as the first working value P _C3 , and the oil pressure of the return oil opening C (ie the working pressure of the engine 400 ) after the movement of the valve insert 1 from the second working position to the first working position (ie switching the traction motor from low speed to high speed) is defined as the second working value P _C4 .

To allow the working pressure value of the engine 400 after switching from low speed to high speed not the limit condition 2 fulfills, which makes it easier to control the motor so that it is stabilized in the high-speed mode, therefore, in the embodiment, the first work value P _C3 fulfills the following boundary condition (as a boundary condition 3 designated): $$P_{C3}<K_1{P}_{C2}.{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="DE112018002268T5\_0016.png,DE112018002268T5\_0017.png"\; state="\{\{state\}\}">K</figure-callout>}}_1<1$$

The maximum input power of the engine 400 is a constant value, and the output torque T , the repression V and the inlet port pressure P (ie the working pressure) of the engine 400 satisfy the following: T = K × V × P, where K is a proportionality factor, hence the output torque T of the motor 400 proportional to the displacement V of the motor 400 and inlet pressure P (ie, the actual working pressure) so that when the working pressure of the engine switching from low speed to high speed is P _C1 , the working pressures P _C3 and P _C1 after switching satisfy P _C3 × V ₂ = P _C1 × V ₁ , and it can also be derived that the first work value P _{C3 is} as follows: $$P_{C3}=\frac{V_1}{V_2}{\mathrm{<figure-callout\; id="1"\; label="P\; C"\; filenames="DE112018002268T5\_0016.png,DE112018002268T5\_0017.png"\; state="\{\{state\}\}">P\; </figure-callout>}}_C$$

Furthermore, based on the formula (7), the formula (8) and the formula (3), the corresponding relationship between the areas A ₁ , A ₂ and A _{3 of} the three chambers is determined.

To allow the actual working pressure of the engine 400 the limit condition after switching from high speed to low speed 1 not met, and in order to facilitate that the motor is controlled to be stabilized in the low speed mode, moreover, similarly, in this embodiment, the second work value P _C4 satisfies the following boundary condition (as a boundary condition 3 designated): $${\mathrm{<figure-callout\; id="4"\; label="P\; C"\; filenames="DE112018002268T5\_0016.png"\; state="\{\{state\}\}">P\; </figure-callout>}}_C>K_2{\mathrm{<figure-callout\; id="1"\; label="P\; C"\; filenames="DE112018002268T5\_0016.png,DE112018002268T5\_0017.png"\; state="\{\{state\}\}">P\; </figure-callout>}}_C.K_2>1$$

When the working pressure of the engine switching from the low speed to the high speed is P _C2 , the working pressures P _C4 and P _C2 after the switching satisfy: P _C4 × V ₁ = P _C2 × V ₂ , and it can also be derived that the first labor value P _{C4 is} as follows: $${\mathrm{<figure-callout\; id="4"\; label="P\; C"\; filenames="DE112018002268T5\_0016.png"\; state="\{\{state\}\}">P\; </figure-callout>}}_C=\frac{V_2}{V_1}{P}_{C2}$$

Furthermore, based on the formula (10), the formula (9) and the formula (6), the corresponding relationship between the areas A ₁ , A ₂ and A _{3 of} the three chambers is determined.

From the above description it can be seen that the relationship between the effective pressure effective areas A ₁ , A ₂ and A _{3 of} the first chamber 1a , the second chamber 1b and the third chamber 1c based on the boundary condition 1 , the boundary condition 2 , the boundary condition 3 and the boundary condition 4 can be determined. In other words, the traction motor switching valve is due to the conception of the effective pressure effective areas A ₁ , A ₂ and A ₃ 100 Designed to be kept stable in a desired speed mode after shifting and not to shift repeatedly so that the entire machine vibrates.

Therefore, according to the boundary condition 1 , the boundary condition 2 , the boundary condition 3 and the boundary condition 4 the traction motor effectively prevented from repeatedly switching between high and low speeds by the effective pressure effective area A _{1 of} the first chamber 1a , the effective pressure effective area A _{2 of} the second chamber 1b and the effective pressure effective area A _{3 of} the third chamber 1c of the traction motor switching valve 100 be conceived and checked as in 2-4 is shown. After completing the design, the operation of the traction motor switching valve can begin 100 Be the following:

If the actual working pressure of the traction motor is greater than P _C1 , the external control oil can use the valve 1 do not push left and the traction motor can only operate in low speed mode; if the actual working pressure of the traction motor is lower than P _C1 , the external control oil pushes the valve core 1 to the left, and if the valve core is switched to the second working position (the traction motor is switched to high speed mode) after it has reached the far left, the traction motor pressure will decrease due to the restriction of the limit condition 3 be lower than K ₁ P _C2 , and since the boundary condition 2 in this case, the traction motor can operate stably in the high speed mode; if the actual working pressure of the traction motor is higher than P _C2 , the valve core becomes 1 moved to the right by the interaction of spring force and all closed chambers, and due to the limitation of the boundary condition 4 the pressure of the traction motor will be higher than K ₂ P _C1 when the traction motor switches to the low speed mode, and since the limit condition 1 in this case, the traction motor can operate stably in the low speed mode.

As can be seen, in the embodiment, by the traction motor switching valve 100 with the first chamber 1a , the second chamber 1b and the third chamber 1c is provided and by the pressure active areas A ₁ , A ₂ and A _{3 of} the first chamber 1a , the second chamber 1b and the third chamber 1c are designed accordingly, the traction motor is kept stable in the corresponding switched-on working mode without frequently switching, thereby effectively solving the problem of vibration of the whole machine, which is beneficial for the life of the traction motor switching valve 100 , to extend the traction motor and even the construction machine and to improve the safety of the construction machine. Furthermore, since no additional control elements and detection elements are necessary, the overall structure is relatively simple, the control is practical, the control accuracy and the operational reliability are relatively high, while the cost is relatively low.

Although it is possible in other embodiments, not shown, the second chamber 1b and the third chamber 1c not in the valve insert 1 to be arranged, for example between the valve insert 1 and the coat 5 or between the valve insert 1 and a specified valve body, the procedure brings the second chamber 1b and the third chamber 1c in the embodiment on the valve insert 1 to be arranged, advantages in that the structure of the traction motor switching valve 100 is relatively simple and compact, the design of the oil path is relatively practical, and, as long as the structure of the valve insert is mainly 1 is designed accordingly, the risk of repeated switching between high and low Speeds are reduced in a simple and practical manner.

Although the diameter of the in 4 shown four sealing sections of the valve insert 1 same, it is further understood that this is not a limitation of the present disclosure, for example, the various sealing portions of the valve insert 1 be designed to have different diameters, or it is also feasible to have some auxiliary holes in the housing 5 to arrange, and the like.

Based on the traction motor switching valve 100 In the present disclosure, the present disclosure also provides a traction motor and a construction machine. The drive motor includes a motor 400 and a swash plate control mechanism 500 with a swashplate of the engine 400 is connected, and it further includes a traction motor switching valve 100 of the present disclosure. The traction motor switching valve 100 is inside the coat 5 of the motor 400 arranged. The construction machine includes the traction motor of the present disclosure, which may be a crawler machine such as an excavator, for example.

The above is only an exemplary embodiment of the present disclosure and is not intended to limit the present disclosure. All changes, equivalent substitutions, improvements, and the like that are made within the spirit and principles of the present disclosure are intended to be included within the scope of the present disclosure.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• CN 201711246964 [0001]

Claims (15)

Travel motor switching valve (100), comprising a valve insert (1), a first working oil opening (Y), a second working oil opening (L), a third working oil opening (Z), an external control opening (X) and a return oil opening (C), the Valve insert (1) has a first working position and a second working position; wherein in the first working position the first working oil opening (Y) is blocked off and the second working oil opening (L) is in communication with the third working opening (Z); wherein in the second working position the first working oil opening (Y) is in communication with the third working oil opening (Z) and the second working oil opening (L) is blocked off; wherein the first working oil port (Y) is for communicating with an oil source, the second working oil port (L) is for communicating with an oil tank, and the third working oil port (Z) is for communicating with a swash plate control mechanism (500) of a traction motor; the external pilot oil port (X) being used to direct the oil to act on a first axial end of the valve insert (1) and to allow the valve insert (1) to tend to move from the first working position to the second working position and the return oil port (C) serves to return the working pressure of a motor (400) of the traction motor to a second axial end of the valve insert (1) and to allow the valve insert (1) to move from the second working position to generate in the first working position; and wherein the traction motor switching valve (100) is designed such that: the valve insert (1) is designed to move from the first working position to the second working position when an oil pressure of the return oil opening (C) is lower than a first predetermined one Value P _C1 , and the valve insert (1) is designed to move from the second working position to the first working position when the oil pressure of the return oil opening (C) is higher than a second predetermined value P _C2 , the first predetermined value P _{C1 is} not equal to the second predetermined value P _C2 ; and an oil pressure of the return oil port (C) is a first work value P _C3 after the valve core (1) has moved from the first work position to the second work position, and an oil pressure of the return oil port (C) is a second work value P _C4 after the Valve insert (1) has switched from the second working position to the first working position, the relationship between the first working value P _C3 and the second predetermined value P _{C2 being} as follows: P _C3 <K ₁ P _C2 , K ₁ ≤1, and wherein the relationship between the second work value P _C4 and the first predetermined value P _{C1 is} as follows: P _C4 > K ₂ P _C1 , K ₂ ≥1. Traction motor switching valve (100) Claim 1 , further comprising a first chamber (1a), a second chamber (1b) and a third chamber (1c), the first chamber (1a) being in communication with the external control oil opening (X), the third chamber (1c) in communication with the return oil opening (C), the second chamber (1b) is in communication with the third working oil opening (Z) and is designed to switch over during the process of moving the valve insert (1) from the first working position to the second working position to communicate alternately with the second working oil opening (L) and the first working oil opening (Y), and an effective pressure effective area of the second chamber (1b) is smaller than that of the third chamber (1c). Traction motor switching valve (100) Claim 2 , further comprising a spring (4), the spring (4) being arranged at the second axial end of the valve insert (1) and exerting an active force on the valve insert (1) which enables the valve insert (1) to have a tendency to move from the second working position to the first working position, the first predetermined value P _{C1 being} as follows: P _C1 = (Px × A ₁ -F ₁ ) / A ₃ , the second predetermined value P _{C2 being} as follows: P _C2 = (Px × A ₁ - F ₂ ) / (A ₃ - A ₂ ), where the first labor value P _{C3 is} as follows: $P_{C3}=\frac{V_1}{V_2}{P}_{C1}.$

P _C3 and where the second labor value P _{C4 is} as follows: $P_{C4}=\frac{V_2}{V_1}{P}_{C2}.$

P _C4 where Px is an oil pressure of the external control oil opening (X), A ₁ , A ₂ and A ₃ are effective pressure active surfaces of the first chamber (1a), the second chamber (1b) and the third chamber (1c), F ₁ and F _{2 are} each active forces of the spring (4) which are exerted on the valve insert (1) in the first working position and in the second working position, and V ₁ and V ₂ respectively displacements of the motor (400) in the first working position and in the second working position. Traction motor switching valve (100) Claim 2 , wherein the second chamber (1b) and the third chamber (1c) are arranged on the valve insert (1) and are respectively positioned at the first axial end and at the second axial end of the valve insert (1). Traction motor switching valve (100) Claim 4 , wherein a first piston chamber (1f) and a second piston chamber (1g) are respectively provided at the first axial end and at the second axial end of the valve insert (1); a first piston (21) being arranged in the first piston chamber (1f) and a second piston (22) being arranged in the second piston chamber (Ig); wherein the second chamber (1b) is positioned between the first piston (21) and an inner wall of the first piston chamber (1f) and the third chamber (1c) is positioned between the second piston (22) and an inner wall of the second piston chamber (Ig) , Traction motor switching valve (100) Claim 4 , wherein a first passage (1d) is arranged on the valve insert (1) and the second chamber (1b) is in communication via the first passage (1d) with one of the first working oil opening (Y) and the second working oil opening (L); and / or wherein a second passage (1e) is arranged on the valve insert (1) and the third chamber (1c) is in communication with the return oil opening (C) via the second passage (1e). Traction motor switching valve (100) Claim 1 , further comprising a first plug part (31) which is arranged at the second axial end of the valve insert (1); wherein a spring (4) of the traction motor switching valve (100) is designed to rest between the first plug part (31) and the second axial end of the valve insert (1) and to exert an active force on the valve insert (1) that is appropriate for the valve insert (1) enables the tendency of movement from the second working position to the first working position to be generated. Traction motor switching valve (100) Claim 7 , wherein a spring receiving chamber (31c) is provided on the surface of the first plug part (31), ie adjacent to the valve insert (1), and wherein the spring (4) is arranged in the spring receiving chamber (31c). Traction motor switching valve (100) Claim 8 , wherein a first through hole (31a) is arranged on the first plug part (31), and wherein the first through hole (31a) is in communication with the spring receiving chamber (31c). Traction motor switching valve (100) Claim 7 , wherein a fastening groove (31b) is arranged on the surface of the first plug part (31), ie away from the valve insert (1). Traction motor switching valve (100) Claim 1 , wherein a narrowing section is arranged at the first axial end of the valve insert (1). Traction motor switching valve (100) Claim 11 , wherein a recess (15) is arranged on a circumferential surface of the constriction section. A traction motor comprising a motor (400) and a swash plate control mechanism (500) drivingly connected to a swash plate of the motor (400), further comprising the traction motor switching valve (100) Claim 1 , wherein the traction motor switching valve (100) is arranged within a casing (5) of the motor (400). Traction motor after Claim 13 , wherein a second through hole (51) is arranged on the casing (5), the valve insert (1) of the traction motor switching valve (100) is arranged in the second through hole (51) and the first working oil opening (Y), the second working oil opening (L ), the third working oil opening (Z), the external control opening (X) and the return oil opening (C) of the traction motor switching valve (100) are all arranged on the inner wall of the casing (5). Construction machine, including the traction motor Claim 13 ,

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