JPH0884Y2 - Bearing preload adjusting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a preload adjusting device for a bearing, such as a spindle of a machine tool, which requires precision and rigidity.

2. Description of the Related Art Conventionally, as a preload adjusting mechanism for a bearing of a main shaft of a machine tool, a two-stage switching system for high speed and low speed or a low position-constant pressure switching system has been used.

Problems to be Solved by the Invention In the two-stage switching system, it is impossible to obtain an optimum preload in the entire rotational speed range because it is impossible to make an adjustment in the middle of the process and the gap at the time of preload switching is large and fine adjustment is not possible. In addition, the constant position-constant pressure switching method has a problem in that the thrust rigidity is low in one direction when the preload is constant.

The present invention has been made in view of the above problems of the prior art, and the purpose thereof is to change the preload steplessly to obtain the optimum preload in the entire region and maintain the bearing rigidity. It is intended to provide a preload adjusting device for a bearing.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention has a rotary shaft on the front side.
A high temperature oil passage formed in the circumferential direction of the housing member that supports and supports the rear bearing, a low temperature oil passage, a temperature sensor provided in the housing, and a high temperature oil passage in the high temperature oil passage. And the heating oil feeding means for feeding the low temperature oil to the low temperature oil passage, and the heating oil feeding means or the cooling oil feeding means for comparing and determining the set target temperature and the measured temperature of the housing. A control means for controlling the oil means is included, and the housing is expanded and contracted based on the measured temperature of the temperature sensor.

Action The NC device stores in advance several target temperatures that define the length of the bearing housing that provides the proper bearing preload corresponding to the machining conditions, and the measured values are output from the temperature sensor of the bearing housing in the operating state, Is compared with the target temperature, and if it is low, high temperature oil flows from the heating device, and if it is high, low temperature oil flows from the cooling device to the high temperature oil passage or the low temperature oil passage of the bearing housing. If necessary, high and low temperature oils are made to flow at the same time so as to reach the target temperature.

Embodiment An explanation will be given below based on FIG. 1 and FIG.

The main shaft 1 is a double cylinder with a front bearing 2 having inner rings fixed in the axial direction and a bearing sleeve 4, 5 having outer rings fixed by a rear bearing 3, and a bearing housing inner cylinder 6 and a bearing housing outer part. The bearing housing is rotatably supported by the cylinder 7, and the bearing housing is mounted on the headstock 8.

At the boundary surface between the bearing housing inner cylinder 6 and the bearing housing outer cylinder 7, a plurality of threads are provided on the outer periphery between the front bearing 2 and the rear bearing 3 with annular grooves a1, a2 to a5 at substantially equal intervals and b1, b1 between them. b2-b5
Has been cut. The annular groove may be a double spiral groove. Further, annular grooves c1 and c2 are formed between the bearing sleeves 4 and 5 and the bearing housing inner cylinder 6. A temperature sensor 9 is embedded in the center of both bearings. Bearing housing Outer cylinder 7 has front bearing 2 and rear bearing 3
The annular grooves c3, c4, c5 are cut at the position.

The cooling device M1 for lowering the oil temperature is provided with a cooling unit including a refrigerator 22a, a condenser 23a, a fan 24a, an evaporator 25a, and a high pressure protection switch 26a above the oil tank 21a. Further, a dual hydraulic pump 27a is provided to send out oil from the oil tank 21a. A temperature sensor 28a is provided in the oil tank 21a.

The cooling device M3 having such a structure and having the room temperature sensor 29
Is another set. Same parts with same number b
Attached.

The heating device M2 that raises the oil temperature is equipped with a heater above the oil tank 41.
42, a double hydraulic pump 43 is provided so that the heated oil in the oil tank is sent out. A temperature sensor 44 for detecting the oil temperature of the oil tank is provided.

The heated oil in the oil tank 41 of the heating device M2 is connected to one side of the dual hydraulic pump 43, the pipe 51, the 4-port electromagnetic switching valve 52, and the bearing housing inner cylinder 6 which is connected from the pipe 53 to the flow passage 54.
Are sent to the respective annular grooves a1 to a5. A high-temperature oil passage is formed from the annular groove a5 through the pipeline 55, the electromagnetic switching valve 52, and the dual hydraulic pump 43, and is heated by the heater 42 and returned to the oil tank 41.

The cooled oil in the hydraulic tank 21a of the cooling device M1 is supplied to one side of the dual hydraulic pump 27a, the pipeline 61, the 4-port electromagnetic switching valve 62, the pipeline.
It is sent from 63 to the annular grooves b1 to b5 connected by the flow path 64. Pipe line 65, electromagnetic switching valve 62, double hydraulic pump from annular groove b5
A low temperature oil flow path is formed which returns to the oil tank 21a cooled by the evaporator 25a of the cooling unit via the other of the 27a.

The oil in the cooled oil tank 21b of the cooling device M3 is pipe 72, annular groove c1, passage 73, annular groove c3, passage 74, annular groove c4, passage 75, annular groove c5, passage 76, annular. A room temperature oil passage is formed, which is cooled by the evaporator 25b of the cooling unit and returned to the oil tank 21b through the groove c2, the passage 77, and the dual hydraulic pump 27b.

Each temperature sensor 9, 28a, 28b, 29, 44 is connected to a connection device (not shown).

In the apparatus thus configured, the machine is operated and the cooling devices M1 and M3 and the heating device M2 are also operated.

Since the cooling device M3 sends the room temperature oil to the room temperature oil flow path, the output of the room temperature sensor 29 and the output of the temperature sensor 28b of the oil tank 21b are input to the control device and are constantly compared with each other so that the room temperature oil is related to other devices. Instead, the cooling unit is independently controlled to be turned on and off. Oil that has been made to be the same as room temperature has an annular groove c
Front bearing sleeve 4, rear bearing sleeve 5 with oil sent to c2
Particularly acts to cool the bearing, and suppresses the adverse effects of abnormal temperature rise of the bearing. Further, the oil sent to the annular grooves c3, c4; c5 acts to prevent thermal displacement of the spindle head.

The cooling device M1 that sends the cooling oil to the low temperature oil passage is the oil tank 21a.
The output of the temperature sensor 28a of is input to the control device and cooled in advance to the target temperature corresponding to the condition from among several target temperatures of the oil tank that are set and input in advance corresponding to the processing and operating conditions. The part is turned on and off.

The heating device M2 that sends high-temperature oil to the high-temperature oil flow path inputs the output of the temperature sensor 44 of the oil tank 41 to the control device and pre-processes it.
The heater 42 is on / off controlled according to the target temperature corresponding to the condition from among several target temperatures of the oil tank which are set and input corresponding to the operating condition. Then, the control device inputs and stores the target temperature of the bearing housing corresponding to the processing conditions, and commands the set temperature appropriately thereto. Further, the target temperatures of the cooling device M1 and the heating device M2 are changed depending on the processing conditions, and the set temperature of the command may become the set temperature of idling. Therefore, the set temperature is commanded as appropriate to the target temperature.

The operation of the cooling device M1 and the heating device M2 and the supply control of the high temperature oil and the low temperature oil are executed according to the flowchart of FIG. When starting execution, the solenoid operated directional control valves 52, 62 do not have to be set at particular positions because they remain in the previous operating state.

In step S1, it is determined whether or not the measured temperature exceeds a target temperature determined according to the processing conditions. If YES, the measured temperature is too high and the bearing housing needs to be cooled, so in step S2, the electromagnetic switching valve 52 is positioned at the position II and the high temperature oil flow passage is closed. In step S3, the electromagnetic switching valve 62 is set to the I position so that the cooled oil in the oil tank 21a is transferred from the pipe lines 61 and 63 to the annular groove b of the bearing housing inner cylinder 6.
It is circulated to 1 to b5 and returned to the cooling device M1 from the pipe 65 through the electromagnetic switching valve 62, cooled by the evaporator 25a and returned to the tank 21a. The bearing housing inner cylinder 6 is cooled and contracted by the circulation of the cold and hot oil, and the distance between the outer rings of the bearings 2 and 3 is shortened to prevent the preload from unnecessarily increasing. When the power is turned off, the internal oil temperature gradually decreases and it takes time to raise the oil temperature next time.Therefore, in step S4, the target temperature is set to the idling of the control device so that the oil temperature of the tank 41a of the heating device M2 is not lowered too much. Switch to the set temperature of and keep the oil temperature in a certain state.
In step S5, the target temperature of the tank 21a of the cooling device M1 is switched to the command set temperature corresponding to the processing conditions. In step S6, the cooling of the oil is continued, and the cooling oil is supplied to the low temperature oil passage of the bearing housing and the temperature sensor 9 of the bearing housing is used.
Continue sending until the actual temperature measured by is the set temperature of the command.

If NO in step S1, the solenoid valve 62 in the low temperature oil flow path is closed at the II position in step S7. In step S8, the solenoid valve 52 is set to the I position to open the high temperature oil flow passage and send the heating oil from the flow passage 53 to the annular grooves a1 to a5. Step
In S9, the target temperature of the tank 21a of the cooling device M1 is switched to the command set temperature. In step S10, heating device M2
The target temperature of the tank 41 is switched to the set temperature for idling. In step S11, the heating of the oil is continued and the heated oil is continuously sent to the high temperature oil passage of the bearing housing until the actually measured temperature of the bearing housing 6 reaches the set temperature of the command.

Effects Since the present invention is configured as described above, the present invention has the following effects.

Since the temperature of the bearing housing is measured and controlled so as to reach the target temperature that meets the processing conditions, the constant position preload of the bearing can be adjusted steplessly, and even in an ultra-high speed rotating machine, an appropriate constant can be set over the entire rotation range. Position preload can be applied.

[Brief description of drawings]

FIG. 1 is a block diagram of the control flow path of the present invention, and FIG. 2 is a control flow chart. 1 ... Main shaft, 2 ... Front bearing, 3 ... Rear bearing, 4 ... Front bearing sleeve, 5 ... Rear bearing sleeve, 6 ... Bearing housing inner cylinder, 7 ... Bearing housing outer cylinder, a1 to a5 , b1 ~ b5,
c1 to c5 …… annular groove, 52,62 …… solenoid switching valve, M1, M3 …… cooling device, M2 …… heating device

Claims (1)

[Scope of utility model registration request] 1. A high temperature oil flow passage formed in a circumferential direction of a housing member for bearing a front and rear bearings of a rotary shaft in a bearing manner, a low temperature oil flow passage, and a temperature sensor provided in the housing. And a comparison of the set target temperature and the actually measured temperature of the housing with the heating oil feeding means for flowing the high temperature oil into the high temperature oil passage, the cooling oil feeding means for feeding the low temperature oil into the low temperature oil passage A preload adjusting device for a bearing, comprising: a control means for controlling the heating oil feeding means or the cooling oil feeding means, and expanding and contracting the housing based on a temperature measured by a temperature sensor.