CN114658590A - A motor and engineering vehicle with variable speed function - Google Patents

Abstract

The invention discloses a motor with speed change function, which comprises a motor rear cover, wherein a hydraulic oil inlet channel and a hydraulic oil outlet channel are arranged in a motor rear cover, a valve core is arranged in the hydraulic oil inlet channel and the hydraulic oil outlet channel, a plurality of channel adjusting grooves are arranged on the inner wall of the adjusting channel, a plurality of valve core adjusting grooves are arranged on the periphery of the valve core, the channel adjusting grooves are communicated with a rotor assembly, the hydraulic oil inlet channel and the hydraulic oil outlet channel, the movement of the valve core controls the disconnection or communication of the channel adjusting grooves and the valve core adjusting grooves, a driving device is arranged on one side of the adjusting channel and used for pushing the valve core to move, an oil supplementing valve core is arranged in the valve core, after the valve core moves, the oil supplementing valve core is used for communicating the first adjusting groove, the second adjusting groove and the third adjusting groove or communicating the second adjusting groove, the third adjusting groove and the fourth adjusting groove, the hydraulic oil in the first adjusting groove or the fourth adjusting groove is supplemented to the second adjusting groove and the third adjusting groove, thereby reducing motor vibration.

Description

A motor and engineering vehicle with variable speed function

technical field

The invention relates to the field of motors, in particular to a motor with a variable speed function and an engineering vehicle.

Background technique

In mines, tunnels and coal mines, heavy-duty transport vehicles are used. The heavy-duty transport vehicles are equipped with hydraulic motors that power them. The hydraulic motors drive the wheels of the transport vehicles to make the vehicles travel. During the traveling of heavy vehicles, according to the complexity of different road conditions, especially in mines, tunnels, and tunnel construction sites, in order to ensure safety, drivers need to accurately control the speed of the vehicle to increase or decrease slowly at any time, so as to achieve safe loading and safe driving. purpose, while taking into account the economic requirements.

One way of the traditional low-speed and high-torque hydraulic motor is to halve the displacement of the hydraulic motor by separately configuring the hydraulic adjustment valve on the hydraulic motor to achieve the purpose of increasing the motor speed. The speed of the hydraulic motor is multiplied, that is to say, the external oil When the source flow is constant, when the motor displacement is reduced to half of the original, the vehicle speed is twice the original at this time. A spool is set in the hydraulic adjustment valve, and the number of channels is changed by the movement of the hydraulic control spool, so as to control the hydraulic pressure to realize the speed change.

The disadvantage of the prior art is that after the motor is shifted, the delivery of hydraulic oil in part of the pipeline is cut off, the hydraulic oil in the cut off pipeline is insufficient, and the hydraulic oil is still affected by the movement of the rotor plunger, where the plunger is located. The change in the volume of the plunger hole results in a vacuum in the line, which causes vibration of the motor.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a motor and an engineering vehicle with a shifting function that can reduce motor vibration during shifting.

The technical solution adopted by the present invention to solve the above technical problems is a motor with a variable speed function, which includes a motor front cover, a motor rear cover, a stator and a rotor assembly connected with the wheel shaft. A plurality of plunger assemblies that move radially are characterized in that a hydraulic oil inlet channel and a hydraulic oil discharge channel are arranged in the rear cover of the motor, and a distribution shaft is also arranged in the rear cover of the motor, and a distribution shaft is arranged in the distribution shaft. Adjustment channel, a valve core is arranged in the adjustment channel, a plurality of channel adjustment grooves are arranged on the inner wall of the adjustment channel, and a plurality of valve core adjustment grooves are arranged around the outer periphery of the valve core, and the channel adjustment groove is connected to the rotor assembly, the hydraulic oil inlet channel and the The hydraulic oil discharge channel, the movement of the valve core controls the disconnection or connection between the channel adjustment groove and the valve core adjustment groove. A drive device is provided on one side of the adjustment channel, and the drive device is used to push the valve core to move. The internal measurement of the valve core Set by the oil charge valve core, after the valve core moves, the oil charge valve core is used to communicate with the first adjustment groove, the second adjustment groove and the third adjustment groove, or to communicate with the second adjustment groove, the third adjustment groove and the fourth adjustment groove Adjustment slot. The hydraulic oil in the first adjusting groove or the fourth adjusting groove is supplemented in the direction of the second adjusting groove and the third adjusting groove.

A further preferred solution of the present invention is: the oil supplement valve core includes a valve body, the valve body can move left and right in the valve cavity, the valve body includes two oil supplement channel components, and the oil supplement channel components include two longitudinal pipes and a Horizontal pipeline, the horizontal pipeline is arranged in the middle of the vertical pipeline, the horizontal pipeline and the vertical pipeline form an I-shaped structure, the outer end of the horizontal pipeline is connected with the valve cavity, and the two oil supply channel components are symmetrically arranged on both sides of the valve body; When the valve core is on the left side, it communicates with the first adjustment groove, the second adjustment groove and the third adjustment groove, and when the oil supply valve core is on the right side, it communicates with the second adjustment groove, the third adjustment groove and the fourth adjustment groove.

A further preferred solution of the present invention is that: the upper port and the lower port of the longitudinal pipe near the outer side are provided with a channel extending to the outer side to the valve cavity.

A further preferred solution of the present invention is as follows: the valve core is provided with two valve core adjustment grooves, and the two valve core adjustment grooves and the sidewall of the valve core are respectively connected to four groups of valve core channels, and the four groups of valve core channels correspond to four groups of valve core channels. a vertical pipe.

A further preferred solution of the present invention is: the four groups of valve core channels are respectively the first group valve core channel, the second group valve core channel, the third group valve core channel and the fourth group valve core channel, and the two valve core channels are respectively The adjustment grooves are respectively the first valve core adjustment groove and the second valve core adjustment groove. The first group of valve core channels is connected to the first valve core adjustment groove, the second group of valve core channels is connected to the side wall of the valve core, and the third group of valve core channels is connected to the side wall of the valve core. The channel communicates with the second valve core adjustment groove, and the fourth group of valve core channels communicates with the side wall of the valve core.

A further preferred solution of the present invention is: when the oil supply valve core is located on the right side, there is a communication gap between the inner longitudinal pipeline of the right fuel supply channel assembly and the third group of valve core channels.

A further preferred solution of the present invention is: the drive device includes an electromagnet and a return spring, the valve core is made of magnetic material, the electromagnet is arranged on one side of the valve core, the return spring is arranged between the electromagnet and the valve core, and the electromagnetic Under the dual action of iron and return spring, the spool is pushed to move.

A further preferred solution of the present invention is: the channel adjustment groove includes a first adjustment groove, a second adjustment groove, a third adjustment groove and a fourth adjustment groove, the hydraulic oil inlet channel is connected to the fourth adjustment groove, and the hydraulic oil discharge channel is connected to the fourth adjustment groove. The first adjustment slot; in the normal state, the first adjustment slot is connected with the second adjustment slot, the third adjustment slot is connected with the fourth adjustment slot, the second adjustment slot is disconnected from the third adjustment slot, and the first adjustment slot The pipelines corresponding to the second, third and fourth adjustment grooves all circulate high pressure hydraulic pressure; after the valve core moves, the first adjustment groove and the second adjustment groove are disconnected, and the third adjustment groove and the fourth adjustment groove are disconnected. When the groove is disconnected, there is no high-pressure hydraulic oil in the pipelines corresponding to the second adjustment groove and the third adjustment groove. A reduction in the amount of management results in an increase in the rotational speed of the motor.

A further preferred solution of the present invention is that: the valve core adjusting groove is a circular groove surrounding the outside of the valve core.

A further preferred solution of the present invention is: the two sides of the valve core adjustment groove are the valve core side walls, the valve core side wall is provided with a buffer groove, and the buffer groove is connected with the valve core adjustment groove on one side Pass.

A further preferred solution of the present invention is as follows: there are two valve core adjustment grooves and four buffer grooves, which are respectively arranged on both sides of the valve core adjustment groove.

According to the present invention, one side of the adjustment channel of the present invention is provided with a driving device, and the driving device is used to push the valve core to move. An adjustment groove, a second adjustment groove and a third adjustment groove, or used to communicate with the second adjustment groove, the third adjustment groove and the fourth adjustment groove. After the spool moves, the hydraulic oil in the second adjustment groove, the third adjustment groove and the corresponding pipeline is cut off. The oil replenishes hydraulic oil to the second adjustment tank and the third adjustment tank to slow down the vibration of the motor.

Description of drawings

Figure 1 is a schematic diagram of the structure of the motor entering oil from the right side of the hydraulic oil into the channel and in a constant speed state;

Figure 2 is a schematic structural diagram of the motor entering oil from the right hydraulic oil into the channel and in a variable speed state;

Figure 3 is a schematic diagram of the structure of the motor entering oil from the hydraulic oil entry channel on the left side and in a state of constant speed;

Figure 4 is a schematic structural diagram of the motor entering oil from the hydraulic oil on the left side into the channel and in a variable speed state;

Fig. 5 is the enlarged view of A place in Fig. 1;

Fig. 6 is the enlarged view of B place in Fig. 2;

Figure 7 is a schematic diagram of the channel adjustment groove and the corresponding pipeline;

FIG. 8 is a schematic structural diagram of an oil charge valve core;

FIG. 9 is a perspective view of the valve core.

Detailed ways

The present invention will be further described in detail below with reference to the embodiments of the accompanying drawings.

As shown in Figures 1 to 9, a motor with variable speed function includes a motor front cover 1, a motor rear cover 2, a stator 3 and a rotor assembly 31 connected to the wheel shaft 4, and the motor front cover 1 is arranged on the left side , the motor rear cover 2 is arranged on the right side, the rotor assembly 31 is arranged in the cavity formed by the motor front cover 1 and the motor rear cover 2, and a plurality of radially movable plungers are arranged on the periphery of the rotor assembly 31 Component 5, the high-pressure hydraulic oil pushes the plunger component 5 to move the piston, and the stator 3 does not move, so that the rotor assembly drives the wheel shaft 4 to rotate, and the rear cover 2 of the motor is provided with a hydraulic oil inlet channel 6 and a hydraulic oil outlet channel 7, As shown in FIGS. 3 and 4 , the functions of the hydraulic oil inlet channel 6 and the hydraulic oil outlet channel 7 can be reversed. The motor rear cover 2 is also provided with a distribution shaft 8, an adjustment channel 9 is arranged in the distribution shaft 8, a valve core 10 is arranged in the adjustment channel 9, and a plurality of channel adjustment grooves 12 are arranged on the inner wall of the adjustment channel 9. A plurality of valve core adjustment grooves 11 are arranged around the outer circumference. The channel adjustment groove 12 and the valve core adjustment groove 11 cooperate with each other to control the quantity of high-pressure hydraulic oil in the pipeline corresponding to the channel adjustment groove 12. The channel adjustment groove 12 communicates with the rotor assembly 31 , The hydraulic oil enters the channel 6 and the hydraulic oil discharge channel 7. The high-pressure hydraulic oil first enters from the hydraulic oil inlet channel 6, passes into the distribution shaft 8, and then enters the rotor assembly 31. The high-pressure hydraulic oil in the rotor assembly 31 After the work is completed, it becomes low-pressure hydraulic oil, and the low-pressure hydraulic oil passes into the distribution shaft 8 again, and finally flows out from the hydraulic oil discharge channel 7 . The movement of the valve core 10 controls the disconnection or connection of the channel adjustment groove 12 and the valve core adjustment groove 11. The valve core 10 is made of magnetic material, and one side of the valve core 10 is provided with an electromagnet 13, and the circuit controls the energization and connection of the electromagnet 13. When power is off, a return spring 14 is arranged between the electromagnet 13 and the valve core 10 , and the valve core 10 is pushed to move under the double action of the electromagnet 13 and the return spring 14 . In the normal speed state, the electromagnet 13 is energized to generate suction to attract the valve core 10 to the right side, and the return spring 14 is compressed between the electromagnet 13 and the valve core 10; when a speed change is required, the electromagnet 13 is powered off, and the return spring 14 pushes The valve core 10 moves to the left, and the movement of the valve core 10 changes the quantity of the high-pressure hydraulic oil circulating in the channel adjustment groove 12, thereby controlling the change of the motor speed.

As shown in Figures 5 and 6, the channel adjustment grooves 12 are sequentially from left to right: a first adjustment groove 21, a second adjustment groove 22, a third adjustment groove 23 and a fourth adjustment groove 24, and the hydraulic oil enters the channel 6 to connect The fourth adjustment groove 24, the hydraulic oil discharge channel 7 is connected to the first adjustment groove 21; in the normal state, the first adjustment groove 21 and the second adjustment groove 22 are connected, and the third adjustment groove 23 and the fourth adjustment groove 24 are connected. , the second adjustment groove 22 and the third adjustment groove 23 are disconnected, and the pipelines corresponding to the first adjustment groove 21 , the second adjustment groove 22 , the third adjustment groove 23 and the fourth adjustment groove 24 all circulate high pressure hydraulic pressure. Specifically, the high-pressure hydraulic oil enters the fourth adjustment groove 24 from the hydraulic oil inlet channel 6 and its own two-way oil inlet channel. And discharged from the hydraulic oil discharge channel 7, the hydraulic oil in the fourth adjustment groove 24 passes into the third adjustment groove 23, the hydraulic oil in the third adjustment groove 23 passes into the oil inlet four-way channel, and the hydraulic pressure in the oil inlet four-way channel After passing through the rotor assembly 31, the oil enters the second adjustment groove 22 and enters the first adjustment groove 21, and finally flows out from the hydraulic oil discharge channel 7, realizing the work of the six-way high-pressure hydraulic oil; after the valve core 10 moves, the first adjustment groove 21 and the second adjustment groove 22 are disconnected, the third adjustment groove 23 and the fourth adjustment groove 24 are disconnected, the pipeline corresponding to the second adjustment groove 22 and the third adjustment groove 23 no longer has high pressure hydraulic oil, and the first adjustment The pipelines corresponding to the groove 21 and the fourth adjustment groove 24 are continuously supplied with high-pressure hydraulic oil, leaving only two high-pressure hydraulic oil to work on the rotor assembly 31, changing from six to two, and a line through which a unit amount of hydraulic oil can pass. decrease, resulting in an increase in the rotational speed of the motor. The valve core adjusting groove 11 is an annular groove surrounding the outside of the valve core 10 . The two sides of the valve core adjustment groove 11 are the valve core side walls 15, and the valve core side wall 15 is provided with a buffer groove 16, and the buffer groove 16 is communicated with the valve core adjustment groove 11 on one side, The contact surface between the buffer groove 16 and the high-pressure hydraulic oil is small, and the initial force generated by it is small, and with the contact of the four adjustment grooves, the force generated is greatly increased due to the large contact surface, which plays a role in providing better performance. A small initial force is provided before a strong force, so that the movement of the valve core 10 is smoother. There are two valve core adjustment grooves 11 , four buffer grooves 16 and are respectively disposed on both sides of the valve core adjustment groove 11 , and the buffer grooves 16 provide buffering effects in all directions.

After the spool 10 moves, the hydraulic oil in the second adjustment groove 22, the third adjustment groove 23 and the corresponding pipeline is cut off, but at this time, the second adjustment groove 22 and the third adjustment groove 23 and the hydraulic oil in the corresponding pipeline are cut off. The hydraulic oil is still affected by the movement of the rotor plunger, and the change in the volume of the plunger hole where the plunger is located causes vacuuming of the second adjusting groove 22, the third adjusting groove 23 and the corresponding pipeline, causing the motor to vibrate. In order to slow down the vibration of the motor, it is necessary to supply hydraulic oil to the second adjusting groove 22, the third adjusting groove 23 and the corresponding pipelines. In the present invention, the hydraulic oil in the first adjusting groove 21 is used to supply the second adjusting groove 22 and the third adjusting groove 23 and the corresponding pipelines. The specific solution is: because the hydraulic oil inlet channel 6 and the hydraulic oil outlet channel 7 are structures that can be reversed, so that other structures and functions can be reversed. As shown in Figures 1 and 2, when the hydraulic oil enters the channel 6 on the right side, the internal measurement of the valve core 10 is set by the oil charge valve core 30, the electromagnet 13 is powered off, and after the valve core 10 moves to the left, the oil charge valve The core 30 is located on the left side, and the oil-filling valve core 30 is used to communicate with the first adjustment groove 21 , the second adjustment groove 22 and the third adjustment groove 23 , so that the hydraulic oil in the first adjustment groove 21 enters the second adjustment groove 22 and the third adjustment groove 23 . in the third adjustment groove 23 . As shown in Figures 3 and 4, when the hydraulic oil enters the channel 6 on the left side, the internal measurement of the valve core 10 is set by the oil supply valve core 30, the electromagnet 13 is powered off, and after the valve core 10 moves to the left, the fuel supply valve The core 30 is located on the right side, and the oil charge valve core 30 communicates with the second adjustment groove 22, the third adjustment groove 23 and the fourth adjustment groove 24, so that the hydraulic oil in the fourth adjustment groove 24 enters the second adjustment groove 22 and the third adjustment groove 24. Adjustment groove 23. The fuel supply valve core 30 includes a valve body 17, which can move left and right in the valve cavity 18. The valve body 17 includes two left and right fuel supply channel assemblies, and the fuel supply channel assembly includes two longitudinal pipes 19 and one transverse pipe 20. , the transverse pipe 20 is arranged in the middle of the longitudinal pipe 19. The transverse pipe 20 and the longitudinal pipe 19 form an I-shaped structure. Both sides; when the oil charge valve core 30 is on the left side, it communicates with the first adjustment groove 21, the second adjustment groove 22 and the third adjustment groove 23, and when the oil charge valve core 30 is on the right side, it communicates with the second adjustment groove 22, the third adjustment groove 22 and the third adjustment groove 23. Adjustment groove 23 and fourth adjustment groove 24 . The upper and lower ports of the longitudinal duct 19 near the outer side are provided with passages 25 extending outwardly to the valve chamber 18 . The valve core 10 is provided with two valve core adjustment grooves 11 . The two valve core adjustment grooves 11 and the side walls of the valve core 10 are respectively connected to four groups of valve core passages, and the four sets of valve core passages correspond to four longitudinal pipes 19 . The four groups of valve core passages are respectively the first set of valve core passages 41 , the second set of valve core passages 42 , the third set of valve core passages 43 and the fourth set of valve core passages 44 , and the two valve core adjustment grooves 11 are respectively the first set of valve core passages 41 . The valve core adjustment groove 51 and the second valve core adjustment groove 52, the first set of valve core passages 41 are connected to the first valve core adjustment groove 51, the second set of valve core passages 42 are connected to the side wall of the valve core 10, and the third set of valve cores The channel 43 communicates with the second valve core adjustment groove 52 , and the fourth set of valve core channels 44 communicates with the side wall of the valve core 10 . When the fuel supply spool 30 is located on the left side, and when the fuel supply valve core 30 is located on the right side, there is a communication gap between the inner longitudinal pipe 19 of the right fuel supply channel assembly and the third group of valve core channels 43 . Due to the structural limitation inside the valve core, the solution of supplying oil with small holes such as the communication gap can also provide sufficient hydraulic oil to the second adjusting groove 22 and the third adjusting groove 23 .

An engineering vehicle includes a motor with a magnetoelectric induction speed change function according to the above technical features. An oil replenishing valve core is arranged in the speed change structure, which can effectively reduce the vibration of the motor.

A motor with a variable speed function provided by the present invention has been introduced in detail above. In this paper, specific examples are used to illustrate the principles and implementations of the present invention. The descriptions of the above embodiments are only used to help understand the present invention and its core ideas. . It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (12)

1. A motor with speed change function comprises a motor front cover, a motor rear cover, a stator and a rotor assembly connected with a wheel shaft, wherein a plurality of plunger assemblies capable of moving in the radial direction are arranged on the periphery of the rotor assembly, and the motor rear cover is internally provided with a hydraulic oil inlet channel and a hydraulic oil outlet channel, a flow distribution shaft is also arranged in the motor rear cover, a regulating channel is arranged in the flow distribution shaft, a valve core is arranged in the regulating channel, a plurality of channel regulating grooves are arranged on the inner wall of the regulating channel, a plurality of valve core regulating grooves are arranged on the periphery of the valve core, the channel regulating grooves are communicated with the rotor assembly, the hydraulic oil inlet channel and the hydraulic oil outlet channel, the movement of the valve core controls the disconnection or the communication of the channel regulating grooves and the valve core regulating grooves, a driving device is arranged on one side of the regulating channel and used for pushing the valve core to move, an oil supplementing valve core is arranged on the inner side of the valve core, after the valve core moves, the oil supplementing valve core is used for communicating the first adjusting groove, the second adjusting groove and the third adjusting groove or communicating the second adjusting groove, the third adjusting groove and the fourth adjusting groove, and hydraulic oil in the first adjusting groove or the fourth adjusting groove is supplemented towards the second adjusting groove and the third adjusting groove.

2. The motor with variable speed function of claim 1, wherein the oil compensating valve core comprises a valve body, the valve body can move left and right in the valve cavity, the valve body comprises two oil compensating passage assemblies, the oil compensating passage assemblies comprise two longitudinal pipelines and a transverse pipeline, the transverse pipeline is arranged in the middle of the longitudinal pipeline, the transverse pipeline and the longitudinal pipeline form an I-shaped structure, the outer ends of the transverse pipelines are communicated with the valve cavity, and the two oil compensating passage assemblies are symmetrically arranged on two sides of the valve body; when the oil supplementing valve core is arranged on the left side, the first adjusting groove, the second adjusting groove and the third adjusting groove are communicated, and when the oil supplementing valve core is arranged on the right side, the second adjusting groove, the third adjusting groove and the fourth adjusting groove are communicated.

3. The motor with variable speed function as claimed in claim 2, wherein the upper and lower ports of the longitudinal duct near the outside are provided with passages extending to the outside to the valve chamber.

4. The motor with variable speed function according to claim 2, wherein the valve core is provided with two valve core adjusting grooves, the two valve core adjusting grooves and the side walls of the valve core are respectively communicated with four groups of valve core passages, and the four groups of valve core passages correspond to four longitudinal pipelines.

5. The motor with variable speed function of claim 4, wherein the four sets of spool passages are a first set of spool passage, a second set of spool passage, a third set of spool passage and a fourth set of spool passage, the two spool adjustment grooves are a first spool adjustment groove and a second spool adjustment groove, the first set of spool passage communicates with the first spool adjustment groove, the second set of spool passage communicates with the side wall of the spool, the third set of spool passage communicates with the second spool adjustment groove, and the fourth set of spool passage communicates with the side wall of the spool.

6. The motor with variable speed of claim 7, wherein when the oil compensating valve core is located at the right side, a communicating gap is formed between the longitudinal channel at the inner side of the right oil compensating channel assembly and the third set of valve core channels.

7. The motor with variable speed of claim 1, wherein the driving means comprises an electromagnet and a return spring, the valve core is made of magnetic material, the electromagnet is disposed on one side of the valve core, the return spring is disposed between the electromagnet and the valve core, and the valve core is driven to move by the dual action of the electromagnet and the return spring.

8. The motor with variable speed function of claim 1, wherein the passage regulating grooves comprise a first regulating groove, a second regulating groove, a third regulating groove and a fourth regulating groove, the hydraulic oil inlet passage is connected with the fourth regulating groove, and the hydraulic oil outlet passage is connected with the first regulating groove; when the hydraulic oil cylinder is in a normal state, the first adjusting groove is communicated with the second adjusting groove, the third adjusting groove is communicated with the fourth adjusting groove, the second adjusting groove is disconnected with the third adjusting groove, and high-pressure hydraulic pressure flows through pipelines corresponding to the first adjusting groove, the second adjusting groove, the third adjusting groove and the fourth adjusting groove; after the valve core moves, the first adjusting groove and the second adjusting groove are disconnected, the third adjusting groove and the fourth adjusting groove are disconnected, high-pressure hydraulic oil is not arranged in pipelines corresponding to the second adjusting groove and the third adjusting groove any more, high-pressure hydraulic oil is continuously filled in the pipelines corresponding to the first adjusting groove and the fourth adjusting groove, and the number of hydraulic oil management can be reduced to increase the rotating speed of the motor.

9. The motor with variable speed as claimed in claim 1, wherein the valve core adjustment groove is a circular groove surrounding the outside of the valve core.

10. The motor with variable speed function of claim 3, wherein the two sides of the valve core adjusting groove are valve core side walls, the valve core side walls are provided with buffer grooves, and the buffer grooves are communicated with the valve core adjusting groove on one side.

11. The motor with variable speed function according to claim 4, wherein the number of the spool adjustment grooves is two, and the number of the buffer grooves is four and is respectively disposed at both sides of the spool adjustment groove.

12. A work vehicle, characterized by comprising a motor with a speed change function according to any one of claims 1 to 11.

Images